TECHNICAL FIELD [0001] The invention relates to a mobile object control apparatus and a mobile object control method for controlling mobile objects, and in particular relates to a computer-readable recording medium on which a program for realizing the apparatus and method is recorded. 10 BACKGROUND ART [0002] A conveyance system that uses an automated guided vehicle (AGV) improves the work efficiency, the production efficiency, and the like, and thus is introduced in various factories. In addition, automated guided vehicles are also introduced in various logistic facilities to realize work 15 efficiency, prompt delivery, and the like. [0003] Moreover, in conveyance systems, it is necessary to avoid a collision between automated guided vehicles at an intersection at which routes that are set for the respective automated guided vehicles in advance intersect, in order to secure safety. [0004] In view of this, as a related technique, Patent Document 1 discloses an information 20 processing apparatus that causes an automated guided vehicle to make a detour and suppresses a decrease in the moving efficiency of the automated guided vehicle, in order to avoid a collision at an intersection. Moreover, Patent Document 2 discloses a system for safely moving a plurality of automated guided vehicles in an efficient manner without a deadlock being caused by interference between automated guided vehicles. 25 LIST OF RELATED ART DOCUMENTS PATENT DOCUMENT [0005] Patent Document 1: Japanese Patent Laid-Open Publication No. 2018-129028 Patent Document 2: Japanese Patent Laid-Open Publication No. 2006-113687 30 SUMMARY OF INVENTION TECHNICAL PROBLEMS [0006] However, regarding automated guided vehicles in Patent Documents 1 and 2, when a 3 plurality of automated guided vehicles enter an intersection at the same time, the automated guided vehicles repeatedly decelerate, stop, start, and accelerate, and thus the loads of the drive motors provided in the automated guided vehicles increase. That is to say, when an automated guided vehicle repeatedly starts from a stop state or stops from an operating state, the current flowing to 5 the drive motor thereof increases. [0007] This is because, when the number of revolutions of the drive motor decreases (nearly a stopped state), the torque increases, and thus the current flowing to the drive motor increases. Therefore, when the current flowing to the drive motor increases, the amount of heat generation of the drive motor increases, and the lubricant of the drive motor deteriorates, thus shortening the 10 lifespan of the drive motor. [0008] An example object of the invention is to provide a mobile object control apparatus, a mobile object control method, and a computer-readable recording medium for performing control so as to extend the lifespan of a mobile object capable of avoiding collisions. 15 SOLUTION TO THE PROBLEMS [0009] In order to achieve the example object described above, a mobile object control apparatus according to an example aspect of the invention includes: an estimation unit configured to estimate whether or not a target first mobile object and a second mobile object that is highly likely to collide with the first mobile object will collide with 20 each other at an intersection; a calculation unit configured to calculate, if it is estimated that the first mobile object and the second mobile object will collide with each other at the intersection, a speed of the first mobile object and a speed of the second mobile object at which a collision at the intersection is avoidable, based on a collision avoidance condition set in advance; and 25 a selection unit configured to select the speed of the first mobile object and the speed of the second mobile object calculated by the calculation unit, based on surrounding temperatures of drive motors of the first mobile object and the second mobile object, or carrying capacities of the first mobile object and the second mobile object, or both the surrounding temperatures and the carrying capacities. 30 [0010] Also, in order to achieve the example object described above, a mobile object according to an example aspect of the invention includes: an estimation unit configured to estimate whether or not a target first mobile object and a second mobile object that is highly likely to collide with the first mobile object will collide with 4 each other at an intersection; a calculation unit configured to calculate a speed of the first mobile object and a speed of the second mobile object at which a collision at the intersection is avoidable, based on a collision avoidance condition set in advance, if it is estimated that the first mobile object and the second 5 mobile object will collide at the intersection; a selection unit configured to select the speed of the first mobile object and the speed of the second mobile object calculated by the calculation unit, based on surrounding temperatures of drive motors of the first mobile object and the second mobile object, or carrying capacities of the first mobile object and the second mobile object, or both the surrounding temperatures and the 10 carrying capacities. [0011] Also, in order to achieve the example object described above, a system that performs moving control of a mobile object according to an example aspect of the invention includes: an estimation unit configured to estimate whether or not a target first mobile object and a second mobile object that is highly likely to collide with the first mobile object will collide with 15 each other at an intersection; a calculation unit configured to calculate, if it is estimated that the first mobile object and the second mobile object will collide with each other at the intersection, a speed of the first mobile object and a speed of the second mobile object at which a collision at the intersection is avoidable, based on a collision avoidance condition set in advance; and 20 a selection unit configured to select the speed of the first mobile object and the speed of the second mobile object calculated by the calculation unit, based on surrounding temperatures of drive motors of the first mobile object and the second mobile object, or carrying capacities of the first mobile object and the second mobile object, or both the surrounding temperatures and the carrying capacities. 25 [0012] Also, in order to achieve the example object described above, a mobile object control method according to an example aspect of the invention includes: an estimation step of estimating whether or not a target first mobile object and a second mobile object that is highly likely to collide with the first mobile object will collide with each other at an intersection; 30 a calculation step of calculating, if it is estimated that the first mobile object and the second mobile object will collide with each other at the intersection, a speed of the first mobile object and a speed of the second mobile object at which a collision at the intersection is avoidable, based on a collision avoidance condition set in advance; and 5 a selection step of selecting the speed of the first mobile object and the speed of the second mobile object calculated by the calculation step, based on surrounding temperatures of drive motors of the first mobile object and the second mobile object, or carrying capacities of the first mobile object and the second mobile object, or both the surrounding temperatures and the carrying 5 capacities. [0013] Furthermore, in order to achieve the example object described above, a computerreadable recording medium according to an example aspect of the invention includes a program recorded on the computer-readable recording medium, the program including instructions that cause the computer to carry out: 10 an estimation step of estimating whether or not a target first mobile object and a second mobile object that is highly likely to collide with the first mobile object will collide with each other at an intersection; a calculation step of calculating, if it is estimated that the first mobile object and the second mobile object will collide with each other at the intersection, a speed of the first mobile 15 object and a speed of the second mobile object at which a collision at the intersection is avoidable, based on a collision avoidance condition set in advance; and a selection step of selecting the speed of the first mobile object and the speed of the second mobile object calculated by the calculation step, based on surrounding temperatures of drive motors of the first mobile object and the second mobile object, or carrying capacities of the first 20 mobile object and the second mobile object, or both the surrounding temperatures and the carrying capacities. ADVANTAGEOUS EFFECTS OF THE INVENTION [0014] As described above, according to the invention, it is possible to extend the lifespan of a 25 mobile object capable of avoiding collisions. BRIEF DESCRIPTION OF THE DRAWINGS [0015] FIG. 1 is a diagram for describing an example of the mobile object control apparatus according to the first example embodiment. 30 FIG. 2 is a diagram for describing an example of a mobile object control apparatus-based system. FIG. 3 is a diagram for describing an example of a mobile object-based system. FIG. 4 shows information indicating an example of movement routes. 6 FIG. 5 shows information indicating an example of the data structure of the route information. FIG. 6 shows information indicating an example of the data structure of the mobile object setting information. FIG. 7 shows information indicating an 5 example of the data structure of the communication delay information. FIG. 8 shows information indicating an example of the data structure of the in-area mobile object information. FIG. 9 is a diagram for describing the collision avoidance condition. 10 FIG. 10 is a diagram showing an example of the data structure of the speed set selection information. FIG. 11 is a diagram for describing an exemplary operation of the mobile object control apparatus according to the first example embodiment. FIG. 12 is a diagram showing an example of the data structure of the speed set selection 15 information. FIG. 13 is a diagram for describing an exemplary operation of the mobile object control apparatus according to the second example embodiment. FIG. 14 is a diagram for showing an example of a computer that realizes the mobile object control apparatus. 20 EXAMPLE EMBODIMENT [0016] (First Example Embodiment) The following describes a first example embodiment of the invention with reference to the drawings. Note that, in the drawings to be described below, the same reference numerals are 25 given to constituent elements that have the same functions or corresponding functions, and a redundant description thereof may be omitted. [0017] [Apparatus configuration] First, the configuration of a mobile object control apparatus 10 according to the first example embodiment will be described with reference to FIG. 1. FIG. 1 is a diagram for describing 30 an example of the mobile object control apparatus according to the first example embodiment. [0018] The mobile object control apparatus 10 shown in FIG. 1 is an apparatus that can extend the lifespan of a mobile object capable of avoiding collision. In addition, as shown in FIG. 1, the mobile object control apparatus 10 includes an estimation unit 11, a calculation unit 12, and a 7 selection unit 19. [0019] Note that, hereinafter, for convenience purposes, a target mobile object 20 (first mobile object) may be referred to as a “mobile object A”, and a mobile object 20 that is highly likely to collide with the target mobile object 20 may be referred to as a “mobile object B” (second mobile 5 object). [0020] The estimation unit 11 estimates whether or not the target mobile object A and the mobile object B that is highly likely to collide with the mobile object A will collide with each other at an intersection. [0021] Specifically, the estimation unit 11 calculates a time at which the mobile object A will 10 arrive at an intersection (first arrival time) and a time at which the mobile object B that is highly likely to collide with the target mobile object A will arrive at the intersection (second arrival time), using position information indicating a position, speed information indicating a speed, intersection position information indicating the position of an intersection, and communication delay time information indicating a communication delay time, for each of the target mobile object A and the 15 mobile object B, and estimates whether or not the mobile object A and the mobile object B will collide with each other at the intersection. [0022] If it is estimated that the mobile object A and the mobile object B will collide at the intersection, the calculation unit 12 calculates a speed of the mobile object A and a speed of the mobile object B at which a collision at the intersection is avoidable, based on a collision avoidance 20 condition set in advance. [0023] Specifically, if it is estimated that the mobile object A and the mobile object B will collide at the intersection, the calculation unit 12 calculates a speed of the mobile object A and a speed of the mobile object B (a speed set 1) at which a collision at the intersection is avoidable, based on distance information indicating the path (for example, the distance) from the mobile object A to 25 the mobile object B by way of the intersection, braking distance information indicating the braking distance of the mobile object A, and a collision avoidance condition expressed using the speed information and the communication delay times of the mobile object A and the mobile object B (first calculation means). [0024] Moreover, if it is estimated that the mobile object A and the mobile object B will collide 30 at the intersection, the calculation unit 12 calculates a speed of the mobile object A and a speed of the mobile object B (a speed set 2) at which a collision at the intersection is avoidable, based on the distance information, braking distance information indicating the braking distance of the mobile object B, and a collision avoidance condition expressed using the speed information and 8 the communication delay times of the mobile object A and the mobile object B (second calculation means). [0025] Here, the path from the mobile object A to the mobile object B via the intersection is a length obtained by adding a path from the mobile object A to the intersection and a path from the 5 mobile object B to the intersection. [0026] The selection unit 19 selects the speed of the mobile object A and the speed of the mobile object B calculated by the calculation unit 12, based on one of or both the surrounding temperatures of the drive motors of the mobile object A and the mobile object B and the carrying capacities of the mobile object A and the mobile object B. That is to say, the selection unit 19 selects the speed 10 set 1 or the speed set 2. [0027] Specifically, if the surrounding temperature of the drive motor of the mobile object A or the mobile object B is higher than or equal to a threshold Th1 (first threshold) for determining a temperature set in advance, the selection unit 19 selects speeds calculated by the calculation unit 12, based on the magnitude relationship between the surrounding temperatures of the drive motors 15 of the mobile object A and the mobile object B. [0028] Moreover, if the surrounding temperatures of the drive motors of the mobile object A and the mobile object B are lower than the threshold Th1 (are not higher than or equal to the threshold Th1), the selection unit 19 selects speeds calculated by the calculation unit 12, based on the magnitude relationship between the carrying capacities of the mobile object A and the mobile 20 object B. [0029] In the first example embodiment, the speeds of mobile objects are changed to speeds that prioritize the lifespans thereof based on the surrounding temperatures of the drive motors of the mobile objects, and thus the lifespans of the mobile objects can be extended. [0030] Moreover, in the first example embodiment, the speeds of mobile objects are changed to 25 speeds that prioritize the carrying efficiencies thereof based on the carrying capacities of the mobile objects, and thus it is possible to suppress a decrease in the carrying efficiencies of the mobile objects. [0031] Furthermore, in the first example embodiment, even if communication delay occurs due to a decrease in the communication quality, the speeds of the mobile objects can be changed to 30 speeds that prioritize the lifespans thereof or speeds that prioritize the carrying efficiencies thereof in consideration of the communication delay times of the mobile objects, and thus it is possible to avoid a collision between the mobile objects. 9 [0032] [System configuration] FIG. 2 is a diagram for describing an example of a mobile object control apparatus-based system. A system 100a shown in FIG. 2 includes the mobile object control apparatus 10 and a plurality of mobile objects 20. The system 100a also includes a storage unit (not illustrated in FIG. 5 2). [0033] Note that the system may have a configuration in which a mobile object 20 is the main element, such as a system 100b shown in FIG. 3. FIG. 3 is a diagram for describing an example of a mobile object-based system. [0034] Note that the configuration of the system is not limited to those of the systems 100a and 10 100b, and a configuration other than those of the systems 100a and 100b may also be adopted. Note that the system will be described below using the system 100a in FIG. 2 for convenience purposes. [0035] The mobile object control apparatus 10 performs, on each of the mobile objects 20, control for moving the mobile object 20 to a target location. 15 [0036] The mobile object control apparatus 10 includes the estimation unit 11, the calculation unit 12, the selection unit 19, a communication unit 13, and an instruction unit 14. The estimation unit 11 includes a collision estimation unit 15 and an arrival time estimation unit 16. The calculation unit 12 includes a passage estimation unit 17 and a collision avoidance speed calculation unit 18. 20 [0037] Note that the mobile object control apparatus 10 is an information processing apparatus such as a server computer. [0038] Each mobile object 20 obtains, from the mobile object control apparatus 10, instruction information to be used for performing moving control of the mobile object 20, and moves to a target location based on the instruction information. 25 [0039] The mobile object 20 includes a communication unit 21, a sensor unit 22, a position estimation unit 23, a movement control unit 24, a movement unit 25, and a temperature sensor 28. The movement unit 25 includes a drive motor 26 and a battery 27. [0040] Note that the mobile object 20 may be an automated guided vehicle, an automatic traveling vehicle, an automated flight vehicle, an automated navigation vessel, a robot, or the like. 30 [0041] The storage unit stores various types of information such as route information, mobile object position information, mobile object setting information, communication delay time information, area information, in-area mobile object information, temperature information, remaining battery level information, and carrying capacity information. 10 [0042] Note that the storage unit may be provided inside or outside the mobile object control apparatus 10. A plurality of storage units may also be provided. [0043] The aforementioned information will be described. The route information is information related to routes on which the mobile objects 20 move. In addition, the route information is created by the user 5 in advance, and is stored in the storage unit. FIG. 4 shows information indicating an example of movement routes. FIG. 5 shows information indicating an example of the data structure of the route information. [0044] The example in FIG. 4 shows a coordinate system for expressing the positions (coordinates) of the mobile objects 20 in a factory/logistic facility, etc., movement routes R1 to 10 R13 (solid line arrows) on which the mobile objects 20 move, and obstacles (hatched ranges). [0045] Route information 51 shown in FIG. 5 includes route identification information “route ID” for identifying each route, route start point information “start point” indicating the coordinates of the start point of the route, route end point information “end point” indicating the coordinates of the end point of the route, pass point information “pass point” indicating coordinates through 15 which the mobile object 20 passes when the mobile object 20 travels from the start point to the end point (coordinates on which the mobile object 20 changes directions), route shape information “shape” indicating the shapes of the movement route, and intersection information “intersection” indicating the position of an intersection on the movement route, which are associated with each other. 20 [0046] Note that information indicating a site from which luggage is carried in, a destination to which luggage is carried, stand-by locations of the mobile objects 20, a charging location of the mobile objects 20, and the like (which are not illustrated in FIG. 4) may be added to the route information 51. [0047] The mobile object position information is information regarding the positions of the 25 mobile objects 20. In addition, the mobile object position information is generated by the mobile objects 20, and is stored in the storage unit. [0048] The mobile object position information is information that includes mobile object identification information for identifying each mobile object 20, position information indicating the position of the mobile object 20, and time-and-date information indicating time and date when 30 the information indicating the position was obtained, which are associated with each other. In addition, speed information indicating the speeds of the mobile objects 20 may be added to the mobile object position information. [0049] The position information is information indicating coordinates, for example. Note that the 11 position information may indicate the positions of the mobile objects 20 using absolute coordinates, relative coordinates, vectors, patches, or the like. [0050] As a method for obtaining the mobile object position information, the mobile object control apparatus 10 may perform polling every certain period of time, and obtain the mobile object position information from the mobile objects 20. 5 Alternatively, the mobile object control apparatus 10 may also obtain mobile object position information that is transmitted by the mobile objects 20 every certain period of time. Alternatively, a configuration may also be adopted in which tags or the like that include position information are installed on a wall, a floor, and the like at a predetermined interval (interval corresponding to coordinates), and every time a mobile object 20 10 passes over a tag, mobile object position information is transmitted to the mobile object control apparatus 10. [0051] The mobile object setting information is information regarding the positions of the mobile objects 20. In addition, the mobile object setting information is created by the user in advance, and is stored in the storage unit. FIG. 6 shows information indicating an example of the data structure 15 of the mobile object setting information. As shown in FIG. 6, mobile object setting information 61 includes mobile object identification information “mobile object ID” for identifying the mobile objects 20, setting speed information “setting speed” indicating moving speeds set for the respective mobile objects 20, and braking distance information “braking distance” indicating the braking distances of the mobile objects 20, which are associated with each other. 20 [0052] The speed of each mobile object 20 suitably set in advance, the maximum speed of the mobile object 20, the maximum speed in the specifications of the mobile object 20, the current speed, or the like may be used as the setting speed information. Also, from the viewpoint of the energetic efficiency, safety at the time of collision, and the like, the maximum allowable speed may also be used as the setting speed information. Furthermore, the maximum acceleration rate or 25 the like of the mobile object 20 may also be used. [0053] A braking distance differs according to a moving speed, and thus a braking distance that differs according to a setting speed may be set as the braking distance information. The braking distance information may have a configuration in which, for example, there are a plurality of stages in the setting speed, and a setting speed for each stage and a braking distance corresponding thereto 30 are associated with each other. In addition, the braking distance information may also be expressed as a percentage of a setting speed. [0054] The braking distance information may be expressed in 10 stages, namely 1 to 10 [%], 11 to 20 [%], …, and 91 to 100 [%] of the setting speed, for example. Furthermore, the braking 12 distance information may also be expressed as a function of the setting speed. As shown in FIG. 6, a value obtained by multiplying the square of a setting speed v by a coefficient (1/100×V2) may be used, for example. In FIG. 6, “km/h” represents “kilometer per hour”. [0055] Note that the mobile object setting information may also be information that includes information indicating the type of each 5 mobile object 20, setting speed information, and the braking distance information, which are associated with each other. [0056] Furthermore, if a mobile object 20 is an automated guided vehicle, the braking distance is affected by the brake performance thereof, friction with a floor surface, the loading capacity thereof, and the like, and thus the mobile object setting information may be generated through 10 experiments, simulation, or the like, in consideration of the influence from these. [0057] The communication delay information is information regarding communication delay times of the mobile objects 20. FIG. 7 shows information indicating an example of the data structure of the communication delay information. As shown in FIG. 7, communication delay information 71 includes identification information “mobile object ID” for identifying the mobile 15 objects 20, communication delay time information “communication delay time [s] for indicating communication delay times (transmission delay times)”, which are associated with each other. In FIG. 7, “s” represents “second”. [0058] The communication delay time information is information indicating a delay time in communication between the mobile object control apparatus 10 and each mobile object 20. 20 Specifically, the communication delay time information indicates a period of time (T1-T0) that has elapsed from a point in time T0 at which the mobile object 20 obtained the most recent mobile object position information to a point in time T1 at which the mobile object control apparatus 10 obtained the mobile object position information. In addition, the communication delay time information may be information for collectively managing several mobile objects 20 based on the 25 communication processing capability of each mobile object 20, a communication protocol to be used, an area in which the mobile object 20 is present, and the like. [0059] Here, if a communication delay time is shorter than a threshold Th0 set in advance (the communication quality has not been decreased), the mobile object control apparatus 10 can accurately detect the position of the mobile object 20. However, if a communication delay time is 30 longer than or equal to the threshold Th0 set in advance (the communication quality has decreased), the mobile object control apparatus 10 cannot accurately detect the position of the mobile object 20. [0060] Assume that, for example, a mobile object 20 moves in one direction at 1 [m] per second, 13 and the mobile object control apparatus 10 receives mobile object position information from the mobile object 20 with a communication delay time of 10 [seconds]. In that case, the mobile object 20 is ahead of the position (coordinates) indicated by the position information by 10 [m], and thus, when the communication quality is decreased, the position of the mobile object 20 deviates largely. Therefore, the likelihood of the 5 mobile objects 20 colliding with each other increases. [0061] The area information is information that is used for extracting a mobile object 20 that is other than the target mobile object 20 and is present near the target mobile object 20 at the present point in time. The area information is information indicating a range set in advance, is created by the user in advance, and is stored in the storage unit. 10 [0062] A range that is set within a certain distance centered on the position (coordinates) of the target mobile object 20, a range that is set to include the position (coordinates) of the target mobile object 20, or a floor of a factory/logistic facility, etc., may be set as the “range”, for example. [0063] The in-area mobile object information is information regarding position information of a mobile object 20 that is present in an area set based on the area information. FIG. 8 shows 15 information indicating an example of the data structure of the in-area mobile object information. [0064] As shown in FIG. 8, in in-area mobile object information 81, area identification information “area ID” for identifying an area corresponding to the target mobile object 20 (the mobile object A), mobile object identification information “mobile object ID” for identifying a mobile object 20 in the area, obtaining time-and-date information “obtaining time and date” 20 indicating time and date when position information of the mobile object 20 in the area was obtained, information “coordinate” indicating position information of the mobile object 20 in the area, and route identification information “route ID” for identifying a route corresponding to the mobile object 20 are associated with each other. Note that the route identification information is not necessary. The reason for providing 25 the route identification information is to make it easy to distinguish which direction to proceed when a mobile object reaches an intersection at which a plurality of movement routes intersect. [0065] The in-area mobile object information may be generated for a mobile object 20 using the area information as described above, or may also be generated in an area set in advance, in a factory/facility, for example. 30 [0066] A configuration may also be adopted in which, for example, in generation of in-area mobile object information for a set area, when a mobile object 20 enters the set area, a sensor apparatus installed in the area detects the mobile object 20, generates in-area mobile object information, and transmits the generated in-area mobile object information to the mobile object 14 control apparatus 10. Alternatively, when entering the area, a mobile object 20 may reads and recognize information regarding the area from a tag installed at an entrance of the area, generate in-area mobile object information, and transmit the generated in-area mobile object information to the mobile object control apparatus 10. The tag may include a QR (Quick Response) code 5 (registered trademark), or the like. [0067] Moreover, a mobile object 20 may request the mobile object control apparatus 10 to transmit in-area mobile object information to the mobile object 20. Such a request may be made at a timing when the mobile object 20 enters an area that includes an intersection at which a collision can occur, a timing when a specific tag is read, or a timing when a certain task was 10 completed, or may be made periodically. [0068] The temperature information is information indicating the surrounding temperature of the drive motor 26 provided in each mobile object 20. [0069] The remaining battery level information is information indicating the residual amount of the battery 27 provided in the mobile object 20. 15 [0070] The carrying capacity information is information indicating the carrying capacity of the mobile object 20. The carrying capacity is expressed by the amount of luggage that can be loaded × speed ( = amount that can be carried per unit time × distance), for example. [0071] The mobile object control apparatus will be described. The communication unit 13 communicates with the communication unit 21 of each 20 mobile object 20. Specifically, the communication unit 13 transmits instruction information for controlling the mobile object 20, and the like to the mobile object 20. In addition, the communication unit 13 receives, from the mobile object 20, mobile object position information, temperature information, remaining battery level information, carrying capacity information, and the like. 25 [0072] The instruction unit 14 generates instruction information to be used for moving the mobile object 20 to a target location. The instruction information includes information for accelerating/decelerating the mobile object 20, for example. [0073] The estimation unit 11 estimates the mobile object B that is highly likely to collide with the target mobile object A at an intersection. That is to say, the estimation unit 11 estimates times 30 at which the mobile object A and the mobile object B will arrive at the intersection, and estimates whether or not the mobile object A and the mobile object B will collide at the intersection. [0074] The calculation unit 12 first estimates whether or not the mobile object A can pass through the intersection before the time at which the mobile object B will arrive at the intersection. Next, 15 if it is estimated that the mobile object A cannot pass through the intersection before the time, the calculation unit 12 calculates speeds of the mobile objects A and B (the speed set 1 or 2) in accordance with a collision avoidance condition in order to avoid a collision with the mobile object B. [0075] The collision avoidance condition is expressed 5 using, for example, distance information indicating the distance between mobile objects, namely the mobile object A and the mobile object B ( = “the sum of the path between the mobile object A and the intersection and the path between the mobile object B and the intersection” ), the braking distance of the mobile object A or B, and setting speed information and communication delay times of the mobile objects A and B. 10 [0076] The selection unit 19 selects one of the speed sets 1 and 2 based on one of or both the surrounding temperatures of the drive motors of the mobile object A and the mobile object B and the carrying capacities of the mobile object A and the mobile object B. [0077] Note that the estimation unit 11, the calculation unit 12, the selection unit 19, and the instruction unit 14 will be described later in detail. 15 [0078] A mobile object will be described. The communication unit 21 communicates with the communication unit 13 of the mobile object control apparatus 10. Specifically, the communication unit 21 transmits the mobile object position information, the temperature information, the remaining battery level information, the carrying capacity information, and the like to the mobile object control apparatus 10. In addition, 20 the communication unit 21 receives, from the mobile object control apparatus 10, instruction information to be used for performing movement control of the mobile object 20, and the like. [0079] The sensor unit 22 is a sensor that detects the state of the mobile object 20, a target object (for example, a tray and a shelf), a sign for assisting movement of the mobile object 20, and an obstacle and the like on an actual route, for example. Specifically, the sensor unit 22 includes one 25 or more of apparatuses such as a radar, an ultrasonic wave sensor, an image capturing apparatus, gyroscope, an encoder, and GPS (Global Positioning System). [0080] The position estimation unit 23 estimates the position of the mobile object 20 itself. Specifically, the position estimation unit 23 obtains measurement information indicating a measurement result of the sensor unit 22, estimates the position of the mobile object 20 itself based 30 on the obtained measurement information, and generates mobile object position information. [0081] The movement control unit 24 controls the movement unit 25 that is provided in the mobile object 20 and is used for moving the mobile object 20. Specifically, the movement control unit 24 controls the movement unit 25 using the above information and the like, and moves the 16 mobile object 20 to a target location. The movement control unit 24 controls a mechanism of the mobile object 20. [0082] The movement unit 25 is a device for moving the mobile object 20. Specifically, if the mobile object 20 is an automated guided vehicle, an electric automobile, or the like, the movement unit 25 is a means that is used for moving a vehicle, such as the 5 drive motor 26, wheels (or crawler), the battery 27, and the like. [0083] The number of revolutions of the drive motor 26 is controlled by the movement control unit 24 in accordance with an operation of the mobile object 20 (for example, start, moving speed, or stop). The drive motor 26 is supplied with power from the battery 27. 10 [0084] The battery 27 is a secondary battery such as a lithium ion battery, a nickel/hydrogen battery, a nickel/cadmium battery, or a lead storage battery. Note that a primary battery may be used as the battery 27. The temperature sensor 28 measures the surrounding temperature of the drive motor 26. [0085] The estimation unit will be described in detail. 15 The collision estimation unit 15 estimates the mobile object B that is highly likely to collide with the target mobile object A at an intersection. [0086] Specifically, the collision estimation unit 15 first obtains mobile object position information from mobile objects 20. Next, the collision estimation unit 15 extracts a mobile object 20 that is present in an area corresponding to the target mobile object 20, using the mobile object 20 position information of the target mobile object 20 and the area information. The collision estimation unit 15 then generates in-area mobile object information related to the extracted mobile object 20, and stores the in-area mobile object information in the storage unit. [0087] Next, the collision estimation unit 15 extracts mobile objects 20 that cannot be detected by the sensor unit 22 of the target mobile object A (mobile objects 20 that are hidden), from the 25 mobile object 20 that is present in the area. [0088] Next, the collision estimation unit 15 refers to the route information, extracts a mobile object 20 that has not arrived at the same intersection the target mobile object A has not arrived at, from among the mobile objects 20 that could not be detected by the sensor unit 22 of the target mobile object A, and sets the extracted mobile object 20 as a collision estimation target. 30 [0089] Next, the collision estimation unit 15 refers to the communication delay information, and obtains communication delay time information corresponding to the mobile object 20 set as a collision estimation target. [0090] Next, if the communication delay time information is higher than or equal to the threshold 17 Th0 set in advance, the collision estimation unit 15 determines that that communication quality has decreased, and estimates that the selected mobile object 20 is the mobile object B that is highly likely to collide with the target mobile object A at the intersection. [0091] The average value, the median, the worst value, variations, or the like of transmission delay times at a predetermined time may be used 5 as communication delay time information. The threshold Th0 may be obtained through experiments, simulation, or the like. [0092] A decrease in the communication quality may be a case where a region of a position at which the mobile object B can be present (for example, a region that is occupied by the mobile object B when it is assumed that the mobile object B moves in all possible directions at the 10 maximum speed from a position thereof that was lastly obtained, during a period (present time - a time at which the position was obtained lastly + transmission delay time) ) has spread to a certain size (the length, the radium, the area, or the like of the region) or larger. [0093] Note that, when the communication quality recovers, and a mobile object 20 that is highly likely to collide with the target mobile object 20 can be detected by the sensor unit 22 of the target 15 mobile object 20, a collision is avoided using a conventional collision avoidance technique. Examples of the conventional collision avoidance technique include priority control that is realized on FIFO (First In First Out) basis at the intersection. [0094] When the mobile object B that is highly likely to collide with the target mobile object A is estimated, the arrival time estimation unit 16 refers to the mobile object setting information, and 20 estimates times at which the target mobile object A and the mobile object B that is highly likely to collide with the target mobile object A will arrive at the intersection. [0095] Specifically, the arrival time estimation unit 16 estimates a time at which the target mobile object A will arrive at the intersection, using the route information indicating a route corresponding to the target mobile object A, the position information indicating the position of the target mobile 25 object A, the intersection position information indicating the position of an intersection that is present on the route, and the speed information indicating the speed of the target mobile object A. [0096] Also, the arrival time estimation unit 16 estimates a time at which the mobile object B will arrive at the intersection, based on the route information indicating a route corresponding to the mobile object B that is highly likely to collide with the target mobile object A, the position 30 information indicating the position of the mobile object B, the intersection position information indicating the position of an intersection that is present on the route, and the setting speed information indicating the setting speed of the mobile object B. [0097] The calculation unit will be described in detail. 18 The passage estimation unit 17 estimates whether or not the target mobile object 20 can pass through the intersection before the time at which the mobile object 20 that is highly likely to collide with the target mobile object 20 will arrive at the intersection. [0098] If it is estimated that the target mobile object 20 cannot pass through the intersection before the time, the collision avoidance speed calculation 5 unit 18 calculates a speed Va of the mobile object A and a speed Vb of the mobile object B (the speed set 1) that satisfy a collision avoidance condition expressed by Formula 1. A description will be given with reference to FIG. 9. FIG. 9 is a diagram for describing the collision avoidance condition. [0099] 10 Formula 1 Dab > Ta × Va + Dsa + Tb × Vb Dab = Da + Db Da: path from the mobile object A to the intersection Db: path from the mobile object B to the intersection 15 Dab: path from the mobile object A to the mobile object B via the intersection Dsa: braking distance of the moving object A Ta: communication delay times of the moving object A Va: moving speeds of moving body A Tb: communication delay times of the moving object B 20 Vb: moving speeds of moving body B [0100] Specifically, the speed set 1 includes the speed Va for decreasing the current speed of the mobile object A and the current speed Vb of the mobile object B. [0101] Moreover, if it is estimated that the target mobile object 20 cannot pass through the intersection before the time, the collision avoidance speed calculation unit 18 calculates the speed 25 Va of the mobile object A and the speed Vb of the mobile object B (the speed set 2) that satisfy a collision avoidance condition expressed by Formula 2. Specifically, the speed set 2 includes the speed Vb for decreasing the current speed of the mobile object B and the current speed Va of the mobile object A. [0102] 30 Formula 2 Dab > Ta × Va + Tb × Vb + Dsb Dab = Da +Db Dsb: braking distance of the moving object B 19 [0103] Moreover, in calculation of Formula 1 and Formula 2 above, the safety may be further increased by multiplying the right side of the collision avoidance condition of each of Formula 1 and Formula 2 by a safety factor α (<1). Formula 3 expresses a collision avoidance condition obtained by multiplying the right side of Formula 1 by the safety factor α. In addition, Formula 4 expresses a collision avoidance condition obtained by multiplying 5 the right side of Formula 2 by the safety factor α. [0104] Formula 3 Dab > α (Ta × Va + Dsa + Tb × Vb) 10 α: safety factor [0105] Formula 4 Dab > α (Ta × Va + Tb × Vb + Dsb) [0106] The selection unit will be described in detail. 15 If the surrounding temperature of the drive motor of the mobile object A or the mobile object B is higher than or equal to the threshold Th1, the selection unit 19 selects a speed set that prioritizes the lifespan, based on the magnitude relationship between the surrounding temperatures of the drive motors of the mobile object A and the mobile object B. In addition, if the surrounding temperatures of drive motors of the mobile object A and the mobile object B are lower than the 20 threshold Th1 (are not higher than or equal to the threshold Th1), the selection unit 19 selects a speed set that prioritizes the carrying efficiency, based on the magnitude relationship between the carrying capacities of the mobile object A and the mobile object B. [0107] Specifically, the selection unit 19 first obtains temperature information of the mobile object A and temperature information of the mobile object B. Next, the selection unit 19 determines 25 whether or not a surrounding temperature Ha of the drive motor of the mobile object A or a surrounding temperature Hb of the drive motor of the mobile object B is higher than or equal to the threshold Th1 for temperature determination. [0108] Next, if the surrounding temperature Ha or Hb is higher than or equal to the threshold Th1, the selection unit 19 refers to speed set selection information 91 shown in FIG. 10, for 30 example, and obtains a speed set that prioritizes the lifespan. FIG. 10 is a diagram showing an example of the data structure of the speed set selection information. [0109] The threshold Th1 is a temperature at which the lubricant of the drive motor 26 deteriorates, for example, and may be obtained through experiments, simulation, or the like. 20 [0110] When the speed set selection information 91 in FIG. 10 is used, the selection unit 19 obtains the speed set 2 if the magnitude relationship between the surrounding temperatures is Ha>Hb, and obtains the speed set 1 if the magnitude relationship between the surrounding temperatures is HaHb, in order to decrease the speed of the mobile object B in which the temperature of the drive motor 26 is low. This prevents the mobile object A from being decelerated, and thus the number of revolutions of the drive motor 26 does not decrease, and the torque does 10 not increase, whereby a current can be suppressed. Therefore, it is possible to suppress an increase in the temperature of the drive motor 26 of the mobile object A. [0112] Moreover, the speed set 1 is selected if the magnitude relationship between the surrounding temperatures is HaCb, and obtains the speed set 1 if the magnitude relationship between the carrying capacities is CaCb, in order to decrease the speed of the mobile object B that has a low carrying capacity. This prevents the mobile object A from being decelerated, and thus it is possible to improve the carrying efficiency of the mobile object A that has a 5 high carrying capacity. [0118] Also, the speed set 1 is selected if the magnitude relationship between the carrying capacities is CaHb, and obtains the speed set 1 if the magnitude relationship between the surrounding temperatures 5 is HaHb, and obtains the speed set 1 if the magnitude relationship between the surrounding temperatures is HaCb, and obtains the speed set 1 if the magnitude relationship between the carrying capacities is CaSb, 25 and obtains the speed set 2 if the magnitude relationship between the remaining battery level is SaSb, in order to decrease the speed of the mobile object A in which the remaining 30 battery level is high. This prevents the mobile object B from being decelerated, and thus it is possible to suppress a drive current to the drive motor 26 of the mobile object B in which the remaining battery level is low, and thereby to suppress the consumption amount of the battery of the mobile object B. 29 [0172] Moreover, the speed set 2 is selected if the magnitude relationship between the remaining battery levels is SaHb, and obtains the speed set 1 if the magnitude relationship between the surrounding temperatures is HaCb, and obtains the speed set 1 if the magnitude relationship between the carrying capacities is CaSb, and obtains the speed set 2 if the magnitude relationship between the remaining battery levels is Sa