Title of Invention: MAINTENANCE PLANNING SYSTEM AND MAINTENANCE PLANNING METHOD
Technical Field
[0001 ] The present invention relates to a system for creating a maintenance plan for a
mechanical product that involves remote monitoring.
Background Art
[0002] In risk-based maintenance (RBM), a risk in case of an occurrence of an
anomaly and a probability of the occurrence are determined for each part of equipment
in a plant or the like, and an optimal maintenance plan is created based on a risk
calculated by multiplying individual risks.
Patent Literature 1 proposes a technique in risk-based maintenance in which a prediction is made as to when damage will occur in equipment or performance degradation will occur in the equipment, and a result of the prediction is treated as a cost to determine an appropriate maintenance time.
[0003] In some types of mechanical equipment, such as an elevator, remote monitoring is implemented to detect an occurrence of an anomaly based on information from a sensor or the like in the machine.
Patent Literature 2 proposes a technique in remote monitoring in which pieces of information collected from various sensors are aggregated, and an anomaly occurrence time is calculated based on the amount of change in the Mahalanobis distance. Citation List

Patent Literature
[0004] Patent Literature 1: JP 2003-303243 A Patent Literature 2: JP 2013-113775 A Summary of Invention Technical Problem
[0005] In providing maintenance service to the owner of a device, a downtime criterion is applied. Specifically, the downtime criterion may be applied when maintenance service is provided for a device that rarely stops operation even if sufficient maintenance quality is not secured, such as an elevator.
However, the downtime criterion does not appropriately reflect the requirements of the owner, so that it is difficult to improve the efficiency of a maintenance plan while maintaining customer satisfaction. [0006] It is an object of the present invention to allow a maintenance plan to be created depending on a tolerable risk specified by an administrator (including an owner).
Solution to Problem [0007] A maintenance planning system according to the present invention includes:
a display unit to display an adjustment screen that includes a risk graph representing a time series of risk values, a tolerance mark representing a tolerance value, an expiration mark representing an expiration date on which a risk value reaches the tolerance value, and a change interface for changing the tolerance value;
an acceptance unit to accept a specified tolerance value specified through the change interface;
an adjustment unit to calculate a new expiration date based on the specified tolerance value and the time series of risk values; and

a planning unit to determine a maintenance work date based on the new expiration date. Advantageous Effects of Invention
[0008] According to the present invention, a maintenance plan can be created depending on a tolerable risk specified by an administrator (including an owner). Brief Description of Drawings
[0009] Fig. 1 is a configuration diagram of a maintenance planning system 100 in a first embodiment;
Fig. 2 is a configuration diagram of a maintenance planning apparatus 200 in the first embodiment;
Fig. 3 is a configuration diagram of a management terminal 300 in the first embodiment;
Fig. 4 is a diagram describing maintenance plan data 120 in the first embodiment;
Fig. 5 is a flowchart of a maintenance planning method in the first embodiment;
Fig. 6 is a diagram illustrating an adjustment screen 130 in the first embodiment;
Fig. 7 is a diagram illustrating workings of the adjustment screen 130 in the first embodiment;
Fig. 8 is a diagram describing a maintenance work date in the first embodiment;
Fig. 9 is a diagram describing a maintenance work date in the first embodiment;
Fig. 10 is a diagram describing a maintenance work date in the first

embodiment;
Fig. 11 is a configuration diagram of the maintenance planning apparatus 200 in a second embodiment;
Fig. 12 is a flowchart of the maintenance planning method in the second
> embodiment;
Fig. 13 is a flowchart of the maintenance planning method in the second embodiment;
Fig. 14 is a diagram illustrating a restriction screen 140 in the second
embodiment;
) Fig. 15 is a diagram describing a maintenance work date in the second
embodiment;
Fig. 16 is a diagram describing a maintenance work date in the second embodiment;
Fig. 17 is a configuration diagram of the maintenance planning apparatus 200 5 in a third embodiment;
Fig. 18 is a configuration diagram of the maintenance planning apparatus 200 in a fourth embodiment;
Fig. 19 is a flowchart of an event handling method in the fourth embodiment;
Fig. 20 is a hardware configuration diagram of the maintenance planning ) apparatus 200 in the embodiments; and
Fig. 21 is a hardware configuration diagram of the management terminal 300 in the embodiments. Description of Embodiments [0010] In the embodiments and drawings, the same elements or corresponding
> elements are denoted by the same reference sign. Description of elements denoted by

the same reference sign will be suitably omitted or simplified. Arrows in the drawings mainly indicate flows of data or flows of processing. [0011] First Embodiment
A maintenance planning system 100 will be described with reference to Figs. 1 to 10. [0012] *** Description of Configuration ***
A configuration of the maintenance planning system 100 will be described with reference to Fig. 1.
The maintenance planning system 100 is a system for creating a maintenance plan for a monitoring target 110.
[0013] The maintenance planning system 100 includes the monitoring target 110, a maintenance planning apparatus 200, and a management terminal 300.
The monitoring target 110, the maintenance planning apparatus 200, and the management terminal 300 communicate with one another via a network 101. [0014] The monitoring target 110 is a device to be remotely monitored and has various sensors 111. For example, the monitoring target 110 is an elevator or an escalator.
The maintenance planning apparatus 200 creates a maintenance plan for the monitoring target 110.
The management terminal 300 is used to manage the maintenance plan. [0015] A configuration of the maintenance planning apparatus 200 will be described with reference to Fig. 2.
The maintenance planning apparatus 200 is a computer that includes hardware such as a processor 201, a memory 202, an auxiliary storage device 203, and a communication device 204. These hardware components are connected with one another via signal lines.

[0016] The processor 201 is an integrated circuit (IC) that performs arithmetic processing and controls the other hardware components. For example, the processor 201 is a central processing unit (CPU), a digital signal processor (DSP), or a graphics processing unit (GPU).
The memory 202 is a volatile storage device. The memory 202 is also referred to as a main storage device or a main memory. For example, the memory 202 is a random access memory (RAM). Data stored in the memory 202 is stored in the auxiliary storage device 203 as needed.
The auxiliary storage device 203 is a non-volatile storage device. For example, the auxiliary storage device 203 is a read-only memory (ROM), a hard disk drive (HDD), or a flash memory. Data stored in the auxiliary storage device 203 is loaded into the memory 202 as needed.
The communication device 204 is a receiver and a transmitter. For example, the communication device 204 is a communication chip or a network interface card (NIC).
[0017] The maintenance planning apparatus 200 includes elements such as a screen unit 211, an adjustment unit 212, and a planning unit 213. These elements are realized by software.
[0018] The auxiliary storage device 203 stores a maintenance planning program for causing a computer to function as the screen unit 211, the adjustment unit 212, the planning unit 213, a storage unit 291, and a communication unit 292. The maintenance planning program is loaded into the memory 202 and executed by the processor 201.
Furthermore, the auxiliary storage device 203 stores an operating system (OS). At least part of the OS is loaded into the memory 202 and executed by the processor

201.
That is, the processor 201 executes the maintenance planning program while executing the OS.
Data obtained by executing the maintenance planning program is stored in a storage device such as the memory 202, the auxiliary storage device 203, a register in the processor 201, or a cache memory in the processor 201.
[0019] The memory 202 functions as the storage unit 291. However, another storage device may function as the storage unit 291 in place of the memory 202 or together with the memory 202.
The communication device 204 functions as the communication unit 292. [0020] The maintenance planning apparatus 200 may include a plurality of processors as an alternative to the processor 201. The plurality of processors share the roles of the processor 201.
[0021 ] The maintenance planning program can be computer-readably recorded (stored) in a non-volatile recording medium such as an optical disc or a flash memory. [0022] A configuration of the management terminal 300 will be described with reference to Fig. 3.
The management terminal 300 is a computer that includes hardware such as a processor 301, a memory 302, and an auxiliary storage device 303, a communication device 304, and an input/output interface 305. These hardware components are connected to one another via signal lines.
[0023] The processor 301 is an IC that performs arithmetic processing and controls the other hardware components. For example, the processor 301 is a CPU, a DSP, or a GPU.
The memory 302 is a volatile storage device. The memory 302 is also

referred to as a main storage device or a main memory. For example, the memory 302 is a RAM. Data stored in the memory 302 is stored in the auxiliary storage device 303 as needed.
The auxiliary storage device 303 is a non-volatile storage device. For example, the auxiliary storage device 303 is a ROM, an HDD, or a flash memory. Data stored in the auxiliary storage device 303 is loaded into the memory 302 as needed.
The communication device 304 is a receiver or a transmitter. For example, the communication device 304 is a communication chip or a NIC.
The input/output interface 305 is a port to which an input device and an output device are connected. For example, the input/output interface 305 is a USB terminal, the input device is a keyboard and a mouse, and the output device is a display. USB is an abbreviation for Universal Serial Bus.
[0024] The management terminal 300 includes a control unit 311 that controls a storage unit 391, a communication unit 392, a display unit 393, and an acceptance unit 394. The control unit 311 is realized by software.
[0025] The auxiliary storage device 303 stores a management program for causing a computer to function as the control unit 311, the storage unit 391, the communication unit 392, the display unit 393, and the acceptance unit 394. The management program is loaded into the memory 302 and executed by the processor 301.
Furthermore, the auxiliary storage device 303 stores an OS. At least part of the OS is loaded into the memory 302 and executed by the processor 301.
That is, the processor 301 executes the management program while executing the OS.
Data obtained by executing the management program is stored in a storage

device such as the memory 302, the auxiliary storage device 303, a register in the processor 301, or a cache memory in the processor 301.
[0026] The memory 302 functions as the storage unit 391. However, another storage device may function as the storage unit 391 in place of the memory 302 or together with the memory 302.
The communication device 304 functions as the communication unit 392.
The input/output interface 305 functions as the display unit 393 and the acceptance unit 394.
[0027] The management terminal 300 may include a plurality of processors as an alternative to the processor 301. The plurality of processors share the roles of the processor 301.
[0028] The management program can be computer-readably recorded (stored) in a non-volatile recording medium such as an optical disc or a flash memory. [0029] Maintenance plan data 120 will be described with reference to Fig. 4.
The maintenance plan data 120 indicates a maintenance plan for the monitoring target 110.
Specifically, the maintenance plan data 120 indicates a visit schedule and a maintenance work schedule. [0030] The visit schedule is a schedule of visit dates.
The visit dates are the dates on which a mechanic visits a target facility.
The target facility is the facility that has the monitoring target 110.
Dashed triangles indicate regular visit dates. [0031] The maintenance work schedule is a schedule of maintenance work dates.
The maintenance work dates are the dates on which the mechanic performs maintenance work on the monitoring target 110.

Solid triangles indicate the maintenance work dates. [0032] The maintenance work dates are determined based on a time series of risk values of the monitoring target 110.
Specifically, a visit date before a risk value (total) reaches a tolerance value is 5 determined as the maintenance work date.
The tolerance value is the value determined as a maximum tolerable risk value. [0033] The risk value (total) is the sum of individual risk values. For example, the risk value (total) is the sum of a risk value A and a risk value B.
The risk value A is the risk value of a failure risk A.
0 The risk value B is the risk value of a failure risk B.
The risk value is the value representing a degree of the failure risk. The failure risk increases as the risk value increases. The failure risk increases as time passes.
[0034] The time series of each type of risk values and initial maintenance plan data 5 120 are obtained by an existing method in risk-based maintenance (RBM).
For example, the time series of each type of risk values and the initial maintenance plan data 120 are obtained by the method disclosed in Patent Literature 1. [0035] *** Description of Operation ***
Operation of the maintenance planning system 100 (operation of the 0 maintenance planning apparatus 200 in particular) corresponds to a maintenance
planning method. The procedure of the maintenance planning method corresponds to
the procedure of the maintenance planning program.
[0036] The maintenance planning method will be described with reference to Fig. 5.
In the description of the maintenance planning method, the risk value signifies 5 the risk value (total).

The initial maintenance plan data 120 is stored in the storage unit 291 of the maintenance planning apparatus 200. Furthermore, the time series of risk values and an initial tolerance value are stored in the storage unit 291 of the maintenance planning apparatus 200.
[0037] In step SI 10, the display unit 393 displays an adjustment screen 130 on the display. [0038] The adjustment screen 130 will be described with reference to Fig. 6.
The adjustment screen 130 has a risk graph 131, a tolerance mark 132, an expiration mark 133, and a change interface 134.
[0039] The risk graph 131 represents the time series of risk values of the monitoring target 110.
Specifically, the risk graph 131 is a line graph representing the time series of risk values. The vertical axis indicates the risk value and the horizontal axis indicates time.
A solid-line portion of the risk graph 131 represents the time series of actual values. The actual values are past risk values.
A dotted-line portion of the risk graph 131 represents the time series of predicted values. The predicted values are future risk values. [0040] The tolerance mark 132 represents the tolerance value. Specifically, the tolerance mark 132 is a straight line.
The expiration mark 133 represents an expiration date. The expiration date is the date on which the risk value reaches the tolerance value. In other words, the expiration date is the date corresponding to the risk value that is the same value as the tolerance value. Specifically, the expiration mark 133 is an arrow pointing to the expiration date.

[0041] The change interface 134 is the interface for changing the tolerance value.
Specifically, the change interface 134 is an increase button and a decrease button. The increase button is pressed to increase the tolerance value, and the decrease button is pressed to decrease the tolerance value. [0042] Referring back to Fig. 5, the procedure of step S110 will be described.
First, the screen unit 211 generates data of the adjustment screen 130.
The communication unit 292 transmits the data of the adjustment screen 130 to the management terminal 300.
The communication unit 392 receives the data of the adjustment screen 130 from the maintenance planning apparatus 200.
Then, the display unit 393 displays the adjustment screen 130 on the display, using the data of the adjustment screen 130.
[0043] The procedure for generating the data of the adjustment screen 130 will be described.
First, the screen unit 211 calculates an initial expiration date based on the time series of risk values and the initial tolerance value. The initial expiration date is the date corresponding to the risk value that is the same value as the initial tolerance value.
The screen unit 211 generates the risk graph 131 based on the time series of risk values, generates the tolerance mark 132 based on the initial tolerance value, and generates the expiration mark 133 based on the initial expiration date.
Then, the screen unit 211 generates the data of the adjustment screen 130. [0044] In step SI20, the acceptance unit 394 accepts a specified tolerance value.
The specified tolerance value is the tolerance value specified through the change interface 134 of the adjustment screen 130. [0045] The procedure of step S120 will be described.

First, an administrator specifies the tolerance value through the change interface 134 by operating the input device of the management terminal 300. Specifically, the administrator presses the increase button or the decrease button by operating the mouse.
The acceptance unit 394 accepts the specified tolerance value. [0046] In step SI30, the adjustment unit 212 calculates a new expiration date.
The new expiration date is the expiration date corresponding to the specified tolerance value. [0047] The procedure of step S130 will be described.
First, the communication unit 392 transmits the specified tolerance value to the maintenance planning apparatus 200.
The communication unit 292 receives the specified tolerance value from the management terminal 300. The storage unit 291 updates the stored tolerance value with the specified tolerance value.
Then, the adjustment unit 212 calculates the new expiration date based on the time series of risk values and the specified tolerance value. The new expiration date is the date on which the risk value reaches the specified tolerance value. In other words, the new expiration date is the date corresponding to the risk value that is the same value as the specified tolerance value. The storage unit 291 updates the stored expiration date with the new expiration date. [0048] In step S140, the screen unit 211 updates the adjustment screen 130.
Specifically, the screen unit 211 moves the tolerance mark 132 on the adjustment screen 130 based on the specified tolerance value, and moves the expiration mark 133 on the adjustment screen 130 based on the new expiration date. [0049] The workings of the adjustment screen 130 will be described with reference to

Fig. 7.
When the increase button, which is the change interface 134, is pressed, the tolerance mark 132 moves upward and the expiration mark 133 moves to the right.
When the decrease button, which is the change interface 134, is pressed, the tolerance mark 132 moves downward and the expiration mark 133 moves to the left. [0050] Referring back to Fig. 5, the procedure of step S140 will be described.
First, the screen unit 211 generates the risk graph 131 based on the time series of risk values, generates the tolerance mark 132 based on the specified tolerance value, and generates the expiration mark 133 based on the new expiration date.
The screen unit 211 generates updated data of the adjustment screen 130.
The communication unit 292 transmits the updated data of the adjustment screen 130 to the management terminal 300.
The communication unit 392 receives the updated data of the adjustment screen 130 from the maintenance planning apparatus 200.
Then, the display unit 393 displays the adjustment screen 130 on the display, using the updated data of the adjustment screen 130.
[0051 ] In step S150, the planning unit 213 determines the maintenance work date based on the new expiration date.
The planning unit 213 registers the maintenance work date in the maintenance plan data 120. [0052] The procedure of step S150 will be described.
First, the planning unit 213 selects the next visit date from the maintenance plan data 120.
The planning unit 213 compares the next visit date with the new expiration date.

If the next visit date is a date before the new expiration date, the planning unit 213 determines a visit date before the new expiration date as the maintenance work date. Specifically, the planning unit 213 selects a visit date immediately preceding the new expiration date from the maintenance plan data 120. The selected visit date is to be the maintenance work date. The planning unit 213 registers the maintenance work date in the maintenance plan data 120.
If the next visit date is a date after the new expiration date, the planning unit 213 determines an additional visit date before the new expiration date as the maintenance work date. Specifically, the planning unit 213 selects one of dates up to the new expiration date. The selected date is to be the additional visit date and the maintenance work date. The planning unit 213 registers the additional visit date in the maintenance plan data 120. The planning unit 213 also registers the maintenance work date in the maintenance plan data 120.
[0053] The determination of the maintenance work date will be described with reference to Figs. 8 to 10.
The current date is after the second visit date and before the third visit date. That is, the next visit date is the third visit date.
In Figs. 8 to 10, three tolerance values are indicated. The first tolerance value is a maximum tolerance value, the second tolerance value is an intermediate tolerance value, and the third tolerance value is a minimum tolerance value. [0054] In Fig. 8, it is assumed that the administrator specifies the first tolerance value.
In this case, the next visit date (the third visit date) is a date before the expiration date, and the visit date immediately preceding the expiration date is the fourth visit date. Therefore, the planning unit 213 determines the fourth visit date as the maintenance work date.

[0055] In Fig. 9, it is assumed that the administrator specifies the second tolerance value.
In this case, the next visit date (the third visit date) is a date before the expiration date, and the visit date immediately preceding the expiration date is the third visit date. Therefore, the planning unit 213 determines the third visit date as the maintenance work date.
[0056] In Fig. 10, it is assumed that the administrator specifies the third tolerance value.
In this case, the next visit date (the third visit date) is a date after the expiration date. Therefore, the planning unit 213 selects a date before the next visit date as an additional visit date, and determines the additional visit date as the maintenance work date. [0057] *** Supplementation of First Embodiment ***
A specific example of the monitoring target 110 is mechanical equipment.
The mechanical equipment is composed of various parts, and the deterioration of each part progresses depending on the number of uses or the passage of time. Therefore, maintenance work (inspection, adjustment, replacement of parts, etc.) is performed regularly in order to prevent an anomaly such as a service outage from occurring. [0058] A specific example of the mechanical equipment is an elevator.
There is implemented remote monitoring for the elevator. In remote monitoring, sensor information obtained by sensors 111 in the machine is gathered at a center. When an anomaly is detected by remote monitoring, a maintenance mechanic is dispatched to the site and performs repair work. [0059] A specific example of the monitoring target 110 or the facility that has the

monitoring target 110 is a plant.
In order to create a rational maintenance plan for the plant, risks are calculated by multiplying a degree of impact and a frequency of occurrence on a per anomaly item basis. Then, risk-based maintenance (RBM) is implemented. In RBM, a maintenance cycle and maintenance details are determined depending on the risks. The degree of impact represents the impact when an anomaly occurs. Specifically, the degree of impact is obtained based on the impact on human life, a financial loss, the time required for handling, or the like. The frequency of occurrence represents a probability of occurrence of an anomaly. In standard RBM, the frequency of occurrence is obtained based on a failure occurrence record of the equipment model or knowledge of the designer.
[0060] Furthermore, with the progress in analysis techniques and simulation techniques, there is proposed a technique for predicting deterioration of a part due to use. Even when simulation is difficult, it is often possible to predict the number of uses or the duration of use time that causes an anomaly to occur by performing a durability test.
[0061 ] Note that the frequency of occurrence of failure increases depending on the deterioration of a part that causes a failure. Therefore, the frequency of occurrence of each failure at a specific timing can be estimated using estimation results obtained by the technique for predicting deterioration.
[0062] When maintenance work is performed, the conditions of parts are improved. As a result, the frequency of occurrence of anomaly is reduced for the parts for which maintenance work has been performed.
[0063] The degree of impact of each anomaly does not change even when the state of deterioration changes. Therefore, the risk at a specific timing can be calculated by

multiplying the frequency of occurrence and the degree of impact.
Note that by setting the degree of impact for a failure that leads to user injury to a significantly higher value than that for a standard failure, the deterioration of an important part is reflected more greatly in the risk.
5 [0064] The maintenance planning system 100 allows the administrator (including the owner of the monitoring target 110) to easily change the tolerance value, which is to be a criterion for performing maintenance work. The risk value of the monitoring target 110 is calculated using RBM.
First, when the monitoring target 110 is installed, the initial tolerance value (the
3 initial value of a tolerance level) is determined. Then, deterioration is predicted using results of an acceleration test, past failure record data, or the like. The time series of risk values is calculated based on prediction results, and the initial maintenance plan data 120 is generated based on the time series of risk values.
When the mechanic visits the site at regular intervals, maintenance work is
5 performed at regular visits shortly before the risk value exceeds the tolerance value. In addition, in order that the risk value does not exceed the tolerance value and the amount of work is minimized, a regular maintenance plan (an initial maintenance plan) is created. At this time, conditions such as manpower planning at the site where maintenance work is performed and dependencies of tasks are considered.
) [0065] After the operation of the monitoring target 110 is started, remote monitoring is performed using the sensors 111 provided in the monitoring target 110. Then, the deterioration status in each part of the monitoring target 110 is grasped.
Note that there are data obtained by deterioration estimation and data obtained by observation, and the data obtained by observation includes measurement variations.
) Therefore, by combining these two types of data using a method such as a Kalman filter,

it is possible to estimate deterioration more accurately. For portions that are not monitored remotely, the state may be estimated using inspection results at visits. [0066] If the differences between the deterioration statuses in all the parts and the deterioration statuses predicted at installation are within a certain range, the maintenance plan does not need to be modified. Therefore, the operation is continued without any modification.
If the difference exceeds the certain range, the maintenance plan is modified. [0067] As a first step of modification, the timing and details of performing regular maintenance are adjusted.
If the deterioration of the state progresses faster than predicted in advance, the maintenance plan is changed so the regular visit to deal with the state is advanced by one visit. If the risk value exceeds the tolerance value due to deterioration shortly before the date on which maintenance is to be performed, the schedule of maintenance work can also be shifted by a few days.
If the deterioration of the state progresses slower than predicted in advance, the maintenance plan can be changed so that the regular visit to deal with the state is delayed by one visit.
Furthermore, by optimizing the maintenance plan, taking into account the same constraints as the ones used in creating the initial maintenance plan, the details of regular maintenance can be finalized.
[0068] If the increase in the risk value cannot be contained within the tolerable range by the first step of modification, the maintenance plan is changed so that non-regular maintenance is performed. In particular, if there is not much time before the risk value reaches the tolerance value, the maintenance plan is changed so that emergency dispatch is carried out. In the emergency attendance, a mechanic rushes to the site to perform

maintenance work on the target portion. If there is sufficient time, the entire maintenance plan of the target machine can be optimized, before performing non-regular maintenance, on the assumption that a visit is to be made for performing non-regular maintenance. This allows maintenance work to be performed on the target portion together with maintenance work on other portions. [0069] Note that when the details of work at the next and subsequent visits are adjusted, the maintenance plan data 120 is updated and monitoring for changes in state is continued based on the updated data. By modifying the maintenance plan when it is found that the maintenance plan cannot cope with the risks, an optimal coping strategy can always be determined according to the maintenance planning system 100. [0070] As this system is operated, the accuracy of deterioration prediction is improved. Therefore, the initial maintenance plan itself may be reviewed over a long time span so that the effect of this improvement is reflected in the initial maintenance plan.
[0071] It is desirable to set the tolerance value of the risk in accordance with the requirements of the administrator.
For example, high-grade hotels require that noise and vibration be maintained at extremely low levels. Medical institutions require extremely short downtime.
In such cases, by setting the tolerance value lower than usual, optimal maintenance plans reflecting the requirements can be created. However, even when the tolerance value is adjusted as in these cases, it is not permissible to allow adjustment to a level that may cause a failure that affects the body of the user. [0072] The risk values are utilized when a maintenance service company creates a maintenance plan, and are also utilized effectively by being disclosed to the administrator in real time.

The maintenance planning system 100 includes the management terminal 300. The management terminal 300 may be provided at a center facility where the maintenance planning system 100 is operated, or may be installed at a remote place connected via the network 101.
The administrator can use the management terminal 300 to check that the maintenance service company is appropriately performing maintenance work while managing the risks of the machine. Furthermore, the administrator can change the tolerance value instantly, based on results of consideration of the appropriate tolerance value.
If the administrator changes the tolerance value, the maintenance plan is re-calculated using the current prediction of the risk value. If the risk value already exceeds the new tolerance value, or if the risk value is predicted to exceed the new tolerance value before the next regular visit, the maintenance planning system 100 makes a plan for non-regular maintenance. This makes it possible to quickly respond to the requirements of the administrator. [0073] *** Effects of First Embodiment ***
The maintenance planning system 100 provides the administrator with the adjustment screen 130, so that the administrator can make appropriate adjustments to the tolerance value. As a result, maintenance service desired by the administrator is provided. Therefore, customer satisfaction can be improved. [0074] *** Other Configuration ***
The maintenance planning system 100 (for example, the maintenance planning apparatus 200) may include a generation unit to generate the initial maintenance plan data 120. The generation unit predicts a time series of future risk values based on a time series of past risk values, and generates the maintenance plan data 120 based on the

time series of future risk values. For the prediction of risk values and the generation of
the maintenance plan data 120, an existing method in risk-based maintenance can be
used.
[0075] Second Embodiment
With respect to an embodiment in which when the next visit date is a date after the new expiration date, the operation of the monitoring target 110 is restricted instead of adding a visit date, differences from the first embodiment will be mainly described with reference to Figs. 11 to 16. [0076] * * * Description of Configuration * * *
The configuration of the maintenance planning system 100 is the same as the configuration in the first embodiment (see Fig. 1).
[0077] The configuration of the maintenance planning apparatus 200 will be described with reference to Fig. 11.
The maintenance planning apparatus 200 further includes a restriction unit 214 and a prediction unit 215.
The maintenance planning program further causes the computer to function as the restriction unit 214 and the prediction unit 215. [0078] *** Description of Operation ***
The maintenance planning method will be described with reference to Figs. 12 and 13.
In step S201 (see Fig. 12), the display unit 393 displays a restriction screen 140 on the display. [0079] The restriction screen 140 will be described with reference to Fig. 14.
The restriction screen 140 has a restriction interface 141.
The restriction interface 141 is the interface for specifying an operational

restriction for the monitoring target 110. The restriction interface 141 includes an interface for specifying a recommended operational restriction.
Specifically, the restriction interface 141 has checkboxes individually for different types of operational restrictions. [0080] Referring back to Fig. 12, the procedure of step S201 will be described.
First, the screen unit 211 generates data of the restriction screen 140.
The communication unit 292 transmits the data of the restriction screen 140 to the management terminal 300.
The communication unit 392 receives the data of the restriction screen 140 from the maintenance planning apparatus 200.
Then, the display unit 393 displays the restriction screen 140 on the display, using the data of the restriction screen 140.
[0081] In step S202, the acceptance unit 394 accepts a specified operational restriction.
The specified operational restriction is the operational restriction specified through the restriction interface 141 on the restriction screen 140. [0082] The procedure of step S202 will be described.
First, the administrator specifies an operational restriction through the restriction interface 141 by operating the input device of the management terminal 300. Specifically, the administrator selects the checkbox of one of the operational restrictions by operating the mouse.
Then, the acceptance unit 394 accepts the specified operational restriction. [0083] Furthermore, the communication unit 392 transmits a notification of the specified operational restriction to the maintenance planning apparatus 200.
The communication unit 292 receives the notification of the specified

operational restriction from the management terminal 300.
Then, the storage unit 291 stores the specified operational restriction. [0084] In step S211, the display unit 393 displays the adjustment screen 130 on the display.
Step S211 is the same as step SI 10 (see Fig. 5) in the first embodiment. [0085] In step S212, the acceptance unit 394 accepts the specified tolerance value.
Step S212 is the same as step SI20 (see Fig. 5) in the first embodiment. [0086] In step S213, the adjustment unit 212 calculates a new expiration date.
Step S213 is the same as step SI30 (see Fig. 5) in the first embodiment. [0087] In step S220, the restriction unit 214 selects the next visit date from the maintenance plan data 120.
Then, the restriction unit 214 compares the next visit date with the new expiration date.
If the next visit date is a date before the new expiration date, processing proceeds to step S221 and step S222.
If the next visit date is a date after the new expiration date, processing proceeds to step S231 (see Fig. 13). [0088] In step S221, the screen unit 211 updates the adjustment screen 130.
The updating method is the same as step SI40 (see Fig. 5) in the first embodiment.
[0089] In step S222, the planning unit 213 determines a visit date before the new expiration date as the maintenance work date. Specifically, the planning unit 213 selects a visit date immediately preceding the new expiration date from the maintenance plan data 120. The selected visit date is to be the maintenance work date.
Then, the planning unit 213 registers the maintenance work date in the

maintenance plan data 120.
[0090] In step S231 (see Fig. 13), the restriction unit 214 restricts the operation of the
monitoring target 110.
Specifically, the restriction unit 214 generates an operational instruction corresponding to the specified operational restriction. Then, the communication unit 292 transmits the generated operational instruction to the monitoring target 110. The monitoring target 110 receives the operational instruction and operates in accordance with the received operational instruction. In this way, the operation of the monitoring target 110 is restricted.
[0091] In step S232, the prediction unit 215 calculates a time series of risk values after the restriction.
The time series of risk values after the restriction is the time series of risk values after the operation of the monitoring target 110 is restricted.
Specifically, the prediction unit 215 calculates a time series of future risks of the monitoring target 110 based on the operation of the monitoring target 110 after the restriction and a time series of past risks of the monitoring target 110.
For the calculation of the time series of risk values, an existing calculation method in risk-based maintenance can be used.
[0092] In step S233, the adjustment unit 212 calculates an expiration date after the restriction.
The expiration date after the restriction is the expiration date corresponding to the specified tolerance value after the operation of the monitoring target 110 is restricted.
[0093] Specifically, the adjustment unit 212 calculates the expiration date after the restriction based on the specified tolerance value and the time series of risk values after

the restriction. The expiration date after the restriction is the date on which the risk value reaches the specified tolerance value. In other words, the expiration date after the restriction is the date corresponding to the risk value that is the same value as the specified tolerance value. The storage unit 291 updates the stored expiration date with the expiration date after the restriction. [0094] In step S234, the screen unit 211 updates the adjustment screen 130.
Specifically, the screen unit 211 moves the tolerance mark 132 on the adjustment screen 130 based on the specified tolerance value, and moves the expiration mark 133 on the adjustment screen 130 based on the expiration date after the restriction.
The procedure of step S234 is the same as the procedure of step SI40 (see Fig. 5) in the first embodiment.
[0095] In step S235, the planning unit 213 determines the maintenance work date based on the expiration date after the restriction.
Then, the planning unit 213 registers the maintenance work date in the maintenance plan data 120.
The procedure of step S235 is the same as the procedure of step SI50 (see Fig. 5) in the first embodiment.
[0096] The determination of the maintenance work date will be described with reference to Figs. 15 and 16.
The current date is after the second visit date and before the third visit date. That is, the next visit date is the third visit date.
[0097] In Fig. 15, the risk graph represents the time series of risk values before the operation of the monitoring target 110 is restricted.
The next visit date (the third visit date) is a date after the expiration date. Therefore, the operation of the monitoring target 110 is restricted.

[0098] In Fig. 16, the risk graph represents the time series of risk values after the operation of the monitoring target 110 is restricted. Since the operation of the monitoring target 110 is restricted, an increase in the risk value is reduced.
The next visit date (the third visit date) is a date before the expiration date, and the visit date immediately preceding the expiration date is the third visit date. Therefore, the planning unit 213 determines the third visit date as the maintenance work date. [0099] *** Supplementation of Second Embodiment ***
If it is difficult to keep an increase in the risk value below the tolerance value simply by modifying the details of work at the planned visit, the operation of the monitoring target 110 is partially restricted, instead of performing non-regular maintenance. In many of the parts, deterioration progresses depending on the number of uses. Therefore, by restricting the number of uses, deterioration can be prevented from progressing. The restriction unit 214 determines an operational restriction level so that the risk value on the next visit date is less than the tolerance value. If the risk value cannot be prevented from increasing only by an operational restriction, the planning unit 213 determines an additional visit date as the maintenance work date. [0100] The details of operational restrictions are determined in advance and registered in the storage unit 291. The details of the operational restrictions can be displayed on the display of the management terminal 300. Furthermore, the implementation status of the operational restrictions can be displayed on the display of the management terminal 300. The administrator can change the details of the operational restrictions on the restriction screen 140.
[0101] When the details of the operational restrictions are changed, the prediction unit 215 newly calculates a time series of risk values. If it is estimated that the risk value

exceeds the tolerance value, the planning unit 213 makes a plan for maintenance so that
non-regular maintenance is performed, as in when an operational restriction is not
implemented.
[0102] An operational restriction may apply to the entire device or may be limited to
the range directly related to a part in which deterioration has progressed.
For example, if deterioration has occurred in a specific landing door of the elevator, the number of uses of the elevator on that floor may be restricted.
If deterioration related to the drive mechanism of the elevator has occurred, the operating speed of the elevator car may be reduced, or the elevator car may be operated so that the number of passengers is limited by changing the setting of a capacity detection unit.
If deterioration has occurred in a landing door, the operating speed or starting acceleration of the door may be reduced when the door is opened and closed.
If deterioration has occurred in a portion of the hoistway, the speed of the elevator car may be reduced only when the elevator car passes the deteriorated portion. [0103] The administrator can select a recommended item (a recommended operational restriction). The recommended item is the item having a slight impact and is selected by reference to a normal use pattern.
[0104] A checking step may be provided before the selected operational restriction is applied. In the checking step, the display unit 393 displays results of the time series of risk values and the next maintenance work date after the restriction that are notified by the maintenance planning apparatus 200. After checking the display, the administrator determines the operational restriction to be applied. After the operational restriction to be applied is determined, the restriction unit 214 restricts the operation of the monitoring target 110.

[0105] When the operational restriction is applied, the restriction unit 214 may notify the user of the monitoring target 110 of the details of the applied operational restriction.
When the monitoring target 110 is the elevator, a message may be displayed on a display in the elevator car, or an email may be sent to an email address registered in advance, or a message may be displayed on a display for advertisement provided in the vicinity of the landing door. [0106] *** Effects of Second Embodiment ***
Even when the next visit date is a date after the new expiration date, one of the visit dates can be made to be the maintenance work date without adding a visit date. [0107] Third Embodiment
With respect to an embodiment in which a recommended operational restriction is suggested, differences from the first embodiment and the second embodiment will be mainly described with reference to Fig. 17. [0108] *** Description of Configuration ***
The configuration of the maintenance planning system 100 is the same as the configuration (see Fig. 1) in the first embodiment.
[0109] The configuration of the maintenance planning apparatus 200 will be described with reference to Fig. 17.
The maintenance planning apparatus 200 further includes a recommendation unit 216.
The maintenance planning program further causes the computer to function as the recommendation unit 216. [0110] *** Description of Operation ***
The recommendation unit 216 determines a recommended operational restriction in advance.

Specifically, the recommendation unit 216 determines the recommended operational restriction based on an operational history of the monitoring target 110.
The operational history of the monitoring target 110 is data indicating the past operational status of the monitoring target 110 and is stored in the storage unit 291 in advance.
[0111] When the administrator sets a permissible range of operational restrictions, it is difficult to clearly specify the permissible range.
Therefore, the recommendation unit 216 determines the recommended operational restriction based on the operational history of the monitoring target 110.
For example, when the monitoring target 110 is the elevator, the recommendation unit 216 finds out frequencies of use on a per time slot basis or on a per floor basis. Then, the recommendation unit 216 selects a time slot or a floor with a slight impact as a restriction target, and determines a use restriction or a speed restriction on the restriction target as the recommended operational restriction. The recommendation unit 216 may select a building whose intended use, number of floors, or the like is similar to that of the building having the elevator of the monitoring target 110, based on building data that indicates information on each building, and determine the recommended operational restriction based on evaluation data on the effects of operational restrictions on the elevator in the selected building. That is, the recommendation unit 216 may determine the recommended operational restriction based on the effects when operational restrictions have been previously applied in a similar building. [0112] *** Effects of Third Embodiment * * *
The recommended operational restriction is determined in the maintenance planning system 100. Therefore, the administrator can restrict the operation of the

monitoring target 110 appropriately by selecting the recommended operational restriction on the restriction screen 140. [0113] Fourth Embodiment
With respect to an embodiment in which a maintenance plan is changed appropriately when an event such as a large-scale disaster occurs, differences from the first embodiment will be mainly described with reference to Figs. 18 to 20. [0114] *** Description of Configuration ***
The configuration of the maintenance planning system 100 is the same as the configuration in the first embodiment (see Fig. 1).
[0115] The configuration of the maintenance planning apparatus 200 will be described with reference to Fig. 18.
The maintenance planning apparatus 200 further includes an event unit 217.
The maintenance planning program further causes the computer to function as the event unit 217. [0116] *** Description of Operation ***
An event handling method will be described with reference to Fig. 19.
The event handling method is part of the maintenance planning method. [0117] In step S410, the event unit 217 determines whether a specified event has occurred.
The specified event is the event that requires a change in the tolerance value, that is, the event that requires a change in the maintenance plan. Specifically, the specified event is a large-scale disaster. [0118] An occurrence of the specified event is detected by a person or a sensor.
When an occurrence of the specified event is detected, an occurrence notification is input to the maintenance planning apparatus 200.

When the occurrence notification is input to the maintenance planning apparatus 200, the event unit 217 determines that the specified event has occurred. [0119] If the specified event has occurred, processing proceeds to step S420.
If the specified event has not occurred, processing terminates. [0120] In step S420, the adjustment unit 212 calculates an event expiration date.
The event expiration date is the expiration date corresponding to an event tolerance value.
The event tolerance value is the tolerance value that is used when the specified event occurs.
[0121] Specifically, the setting range for the tolerance value is stored in the storage unit 291 in advance.
The adjustment unit 212 selects the upper limit tolerance value from the setting range, and calculates the event expiration date based on the upper limit tolerance value and the time series of risk values. The event expiration date is the date on which the risk value reaches the upper limit tolerance value. In other words, the event expiration date is the date corresponding to the risk value that is the same value as the upper limit tolerance value. The storage unit 291 updates the stored tolerance value with the upper limit tolerance value, and updates the stored expiration date with the event expiration date.
[0122] In step S430, the planning unit 213 determines a new maintenance work date based on the event expiration date.
Then, the planning unit 213 changes the maintenance work date registered in the maintenance plan data 120 to the new maintenance work date.
The procedure for determining the new maintenance work date is the same as the procedure for determining the maintenance work date in step SI50 (see Fig. 5) in

the first embodiment.
[0123] * * * Supplementation of Fourth Embodiment * * *
When a large-scale disaster occurs, a large amount of emergency work such as
restoration work will ensue, so that shortage of personnel resources is expected.
5 Even when a large-scale disaster occurs, the administrator wishes to use the
equipment as much as possible.
Therefore, when a large-scale disaster occurs, the adjustment unit 212
automatically raises the tolerance value. However, the adjustment unit 212 makes the
raised tolerance value coincide with the upper limit of the tolerance value that can be 0 normally set. That is, the tolerance value is raised only when the tolerance value has
been set low.
As a result of this, maintenance work can be prevented from increasing while
giving priority to the handling of an emergency.
[0124] The raising of the tolerance value in an emergency is explicitly indicated to the 5 administrator in advance. For example, the display unit 393 displays a notification
screen indicating the applicable conditions and the range of change on the display.
[0125] Depending on the intended use of the monitoring target 110, priority
maintenance work is required even in an emergency. For example, a device in a
medical institution requires priority maintenance work even in an emergency.
0 For the monitoring target 110 like this, it can be arranged that the raising of the
tolerance value is precluded.
In addition, the amount by which the tolerance value is raised can be set to vary
depending on the scale of the disaster. For example, the tolerance value corresponding
to the scale of the disaster may be selected from a table in which disaster scales and 5 tolerance values are associated with each other.

In this way, even in the case of service in an emergency, appropriate service in line with the intention of the administrator can be provided by management based on the risk value and the tolerance value.
[0126] Furthermore, when a large-scale disaster occurs, more appropriate service can be performed by restricting the operation of the monitoring target 110 in accordance with an operational restriction to be applied upon occurrence of a disaster (an event operational restriction).
[0127] In addition, the display unit 393 can display, on the display, a setting screen for specifying the tolerance value and operational restriction to be applied in an emergency. The administrator can specify the tolerance value and operational restriction to be applied in an emergency on the setting screen in the same manner as when the tolerance value and operational restriction are specified in the normal state. [0128] *** Other Configuration ***
The fourth embodiment may be implemented in combination with the second embodiment or the third embodiment. That is, the maintenance planning apparatus 200 may include the restriction unit 214, the prediction unit 215, and the recommendation unit 216. [0129] * * * Supplementation of Embodiments * * *
The maintenance planning apparatus 200 finds out the frequency of occurrence of each failure mode, using information on the states of deterioration of the parts constituting the device grasped by remote monitoring. The maintenance planning system 100 calculates the risk value for each failure mode by multiplying the frequency of occurrence of each failure mode by the degree of impact obtained based on the impact of each failure mode at the time of occurrence, and obtains the sum of individual risk values.

The maintenance planning apparatus 200 compares a pre-set tolerable risk value with the current total risk value of the equipment. Then, the maintenance planning apparatus 200 modifies the maintenance work plan for the equipment at a stage when it is predicted that the tolerable risk value will be exceeded.
The management terminal 300 displays the actual value of the total risk value and a predicted time series change in the total risk value to the administrator (including the owner of the equipment). The administrator can perform an operation to change the tolerable risk value at the management terminal 300 based on the displayed total risk value.
The maintenance planning apparatus 200 detects that the operation has been performed, and modifies the maintenance work plan.
Basically, maintenance work is planned and performed based on the pre-set tolerance value. However, by arranging that the administrator changes the tolerance value depending on the situation, maintenance service can be provided at a level required by the administrator.
[0130] The maintenance planning apparatus 200 has a model of progress of deterioration in elements as time passes or the number of uses increases acquired by an acceleration test.
The maintenance planning apparatus 200 utilizes both the output of the deterioration progress model and information on results of remote monitoring when using results of estimation of the states of deterioration in the parts.
In the estimation of the states of deterioration in the parts, the states can be estimated with higher accuracy by integrating calculation results in the time-series model estimated by the acceleration test in advance with data from remote monitoring and data from inspections at visits.

[0131] When the total risk is estimated to exceed the tolerance value before the next scheduled visit, the maintenance planning apparatus 200 configures the machine remotely so that the operation (number of times or speed) of the device (as a whole or partially) is restricted (or reduced). The maintenance planning apparatus 200 also manages the details of the operational restrictions.
[0132] The management terminal 300 displays, to the administrator, the details of permissible operational restrictions and the details of an actually applied operational restriction. An operation to rewrite the details of the permissible operational restrictions can be performed at the management terminal 300.
The maintenance planning apparatus 200 detects that the operation has been performed, and modifies the maintenance work plan.
If a part is not likely to survive until the next scheduled regular maintenance due to sudden deterioration in the part, implementing an operational restriction can prevent the deterioration in the part from progressing and can prevent additional maintenance work from being performed. The types of operational restrictions to be permitted need to be set at the time of contract. The range of operational restrictions includes complete suspension. However, if an operational restriction is actually applied, there may be a great impact and prompt removal of the operational restriction may be desired. Therefore, the administrator is allowed to easily change the details of the operational restriction or remove the operational restriction. [0133] The maintenance planning apparatus 200 extracts conditions under which the number of times service is performed is small, based on operational history data on a per time slot basis or on a per target operation basis in the target device in the normal state. Then, the maintenance planning apparatus 200 selects the target and details of the operational restriction, and causes the management terminal 300 to display the

selected information as recommendation details.
[0134] When a predetermined serious event occurs, such as in a large-scale disaster, the maintenance planning apparatus 200 temporarily changes the tolerance value set for each piece of equipment to a higher value than normal.
When there is a high probability of shortage of maintenance resources, such as in a large-scale disaster, the amount of maintenance work can be prevented from increasing by changing the tolerable risk value of each machine. However, the maximum tolerable risk up to which a change can be made (the minimum at which the impact on the body of the user can be avoided) is not changed, and the tolerance value of a machine for which the tolerance value has been set low is raised within the range up to the maximum value.
[0135] When a predetermined serious event occurs, such as in a large-scale disaster, the maintenance planning apparatus 200 temporarily changes the details of the permissible operational restrictions set for each piece of equipment to a broader range than usual. [0136] This applies to the elevator or the escalator.
The maintenance planning apparatus 200 restricts the number of times the doors are opened and closed on a specific floor during a certain period of time to a certain number of times or less, and does not provide a service in response to a call in excess of that number of times. Alternatively, the maintenance planning apparatus 200 only assigns another machine in the same bank.
The maintenance planning apparatus 200 restricts the starting acceleration or operating speed at opening and closing of the doors on a specific floor or on all floors.
The maintenance planning apparatus 200 changes the value of a determination criterion in the device for which a determination is made as to whether or not running is

allowed, in all runs, in runs in a specific direction, or in services from a specific floor, based on the measurement setting value of a sensor for detecting the capacity in the car or the output of this sensor.
[0137] A hardware configuration of the maintenance planning apparatus 200 will be described with reference to Fig. 20.
The maintenance planning apparatus 200 includes processing circuitry 209.
The processing circuitry 209 is hardware that realizes the screen unit 211, the adjustment unit 212, the planning unit 213, the restriction unit 214, the prediction unit 215, the recommendation unit 216, the event unit 217, and the storage unit 291.
The processing circuitry 209 may be dedicated hardware, or may be the processor 201 that executes programs stored in the memory 202. [0138] When the processing circuitry 209 is dedicated hardware, the processing circuitry 209 is, for example, a single circuit, a composite circuit, a programmed processor, a parallel-programmed processor, an ASIC, an FPGA, or a combination of these.
ASIC is an abbreviation for Application Specific Integrated Circuit, and FPGA is an abbreviation for Field Programmable Gate Array.
The maintenance planning apparatus 200 may include a plurality of processing circuits as an alternative to the processing circuitry 209. The plurality of processing circuits share the roles of the processing circuitry 209.
[0139] In the maintenance planning apparatus 200, some of the functions may be realized by hardware, and the rest of the functions may be realized by software or firmware.
[0140] The processing circuitry 209 can thus be realized by hardware, software, firmware, or a combination of these.

[0141] A hardware configuration of the management terminal 300 will be described with reference to Fig. 21.
The management terminal 300 includes processing circuitry 309.
The processing circuitry 309 is hardware that realizes the control unit 311 and the storage unit 391.
The processing circuitry 309 may be dedicated hardware, or may be the processor 301 that executes programs stored in the memory 302. [0142] When the processing circuitry 309 is dedicated hardware, the processing circuitry 309 is, for example, a single circuit, a composite circuit, a programmed processor, a parallel-programmed processor, an ASIC, an FPGA, or a combination of these.
The management terminal 300 may include a plurality of processing circuits as an alternative to the processing circuitry 309. The plurality of processing circuits share the roles of the processing circuitry 309.
[0143] In the management terminal 300, some of the functions may be realized by hardware, and the rest of the functions may be realized by software or firmware. [0144] The processing circuitry 309 can thus be realized by hardware, software, firmware, or a combination of these.
[0145] The embodiments are examples of preferred embodiments and are not intended to limit the technical scope of the present invention. The embodiments may be implemented partially, or two or more of the embodiments may be implemented in combination. The procedures described using the flowcharts or the like may be suitably changed. Reference Signs List [0146] 100: maintenance planning system, 101: network, 110: monitoring target, 111:

sensors, 120: maintenance plan data, 130: adjustment screen, 131: risk graph, 132: tolerance mark, 133: expiration mark, 134: change interface, 140: restriction screen, 141: restriction interface, 200: maintenance planning apparatus, 201: processor, 202: memory, 203: auxiliary storage device, 204: communication device, 209: processing circuitry, 211: screen unit, 212: adjustment unit, 213: planning unit, 214: restriction unit, 215: prediction unit, 216: recommendation unit, 217: event unit, 291: storage unit, 292: communication unit, 300: management terminal, 301: processor, 302: memory, 303: auxiliary storage device, 304: communication device, 305: input/output interface, 309: processing circuitry, 311: control unit, 391: storage unit, 392: communication unit, 393: display unit, 394: acceptance unit

[Claim 1] A maintenance planning system comprising:
a display unit to display an adjustment screen that includes a risk graph representing a time series of risk values, a tolerance mark representing a tolerance value, an expiration mark representing an expiration date on which a risk value reaches the tolerance value, and a change interface for changing the tolerance value;
an acceptance unit to accept a specified tolerance value specified through the change interface;
an adjustment unit to calculate a new expiration date based on the specified tolerance value and the time series of risk values; and
a planning unit to determine a maintenance work date based on the new expiration date.
[Claim 2] The maintenance planning system according to claim 1, further comprising
a screen unit to move the tolerance mark on the adjustment screen based on the specified tolerance value, and move the expiration mark on the adjustment screen based on the new expiration date.
[Claim 3] The maintenance planning system according to claim 1 or claim 2,
wherein the risk graph is a line graph,
wherein the tolerance mark is a straight line, and
wherein the change interface is an increase button for raising the tolerance mark and a decrease button for lowering the tolerance mark.

[Claim 4] The maintenance planning system according to claim 1 or claim 2,
wherein the planning unit selects a next visit date from maintenance plan data that indicates a visit schedule, and determines a visit date before the new expiration date as the maintenance work date when the next visit date is a date before the new expiration date.
[Claim 5] The maintenance planning system according to claim 4,
wherein the planning unit determines an additional visit date before the new expiration date as the maintenance work date when the next visit date is a date after the new expiration date.
[Claim 6] The maintenance planning system according to claim 4, further comprising:
a restriction unit to restrict operation of a monitoring target when the next visit date is a date after the new expiration date; and
a prediction unit to calculate a time series of risk values after restriction when the next visit date is a date after the new expiration date,
wherein the adjustment unit calculates an expiration date after restriction based on the specified tolerance value and the time series of risk values after restriction, and
wherein the planning unit determines the maintenance work date based on the expiration date after restriction when the next visit date is a date after the new expiration date.
[Claim 7] The maintenance planning system according to claim 6,
wherein the display unit displays a restriction screen that includes a restriction interface for specifying an operational restriction on the monitoring target,

wherein the acceptance unit accepts a specified operational restriction specified through the restriction interface,
wherein the restriction unit restricts operation of the monitoring target in accordance with the specified operational restriction when the next visit date is a date after the new expiration date, and
wherein the prediction unit calculates the time series of risk values after restriction based on the specified operational restriction when the next visit date is a date after the new expiration date.
[Claim 8] The maintenance planning system according to claim 7,
wherein the restriction interface includes an interface for specifying a recommended operational restriction.
[Claim 9] The maintenance planning system according to claim 8, further comprising a recommendation unit to determine the recommended operational restriction based on an operational history indicating past operational status of the monitoring target.
[Claim 10] The maintenance planning system according to any one of claims 6 to 9, wherein the monitoring target is an elevator or an escalator.
[Claim 11] The maintenance planning system according to any one of claims 1 to 10,
further comprising
an event unit to determine whether or not a specified event has occurred, wherein the adjustment unit calculates an event expiration date based on an

event tolerance value and the time series of risk values when the specified event has occurred, and
wherein the planning unit changes the maintenance work date based on the event expiration date when the specified event has occurred.
[Claim 12] A maintenance planning method comprising:
displaying an adjustment screen that includes a risk graph representing a time series of risk values, a tolerance mark representing a tolerance value, an expiration mark representing an expiration date on which a risk value reaches the tolerance value, and a change interface for changing the tolerance value, by a display unit;
accepting a specified tolerance value specified through the change interface, by an acceptance unit;
calculating a new expiration date based on the specified tolerance value and the time series of risk values, by an adjustment unit; and
determining a maintenance work date based on the new expiration date, by a planning unit.