DESC:TECHNICAL FIELD
[0001] The present invention relates generally to an apparatus for wave shaping of velocity commands for servo drives.

BACKGROUND
[0002] Typically, servo drives follow an input from a user control or a position feedback loop. A user normally provides commands to the servo systems using a rate command, which is generated using a transducer, such as a potentiometer mounted on a handle to generate the rate command proportional to an output of the transducer.

[0003] For example, Figure 1 illustrates a schematic diagram (100) depicting an input output relation of a linear potentiometer. In Figure 1(a), a voltage divider is shown with a transfer function of VOUT = VIN(RB/RPOT), where RPOT = RA + RB, and RA and RB represent the resistances from VIN to a wiper, and from the wiper to ground, respectively. Stepping the wiper from the bottom of the pot to the top with VIN at a constant 5V level, generates a linear transfer function. This is shown in the linear-response plot as shown in Figure 1(b), which represents VOUT versus tap position data.

[0004] US4587510A titled “Analog Joystick Controller” discloses a handle shaft engageable with two yokes rotatably movable respectively about two perpendicular axes in response to tilting of the handle shaft. The yokes are respectively coupled to the wipers of two potentiometers, the resistance portions of which are fixedly connected to adjusting means and manually movable for zero adjustments. The potentiometer used is a linear wire wound resistor whose resistance varies linearly based on a wiper angle. The varying resistance produces a proportional voltage and generates an analog velocity command. This, however, becomes difficult to provide a command to the servo drive at lower speeds due to variation in holding the control handle and noise.

[0005] This difficulty is overcome by using a non-linear variation in the resistance, based on the wiper angle. By using this method, the winding is done in non-linear manner, so that the variation in resistance is lower near zero angle and exponential increasing at the maximum angle of deflection. Figure 2 illustrates a schematic diagram (200) depicting an input output relation of a cosine potentiometer. In Figure 2(a), if the position of a potentiometer changes, an input output relation is also changed. In other words, when the potentiometer rotates, the potentiometer needs some voltage to generate inputs, such as speed commands. Figure 2(b) represents an output of the cosine potentiometer which represents voltage versus rotation.

[0006] Further, US4420808A titled “Multi-Axis Force Stick, Self-Trimmed Aircraft Flight Control System” introduces signal conditioning that provides a dead band to avoid integrating minute, inadvertent force signal outputs, and Vernier sensitivity at low forces with high gain at high forces.

[0007] US5347204A titled “Position Dependent Rate Dampening in any Active Hand Controller” discloses that hardware as well as software implementations can provide dependent dampening to the sticks such that when the wiper is located about a null, a higher rate of dampening is provided than when the wiper is located outside the null, where a lower rate of dampening is provided. The dual or triple slope control is used to get better low speed control and smoothness. Figure 3 illustrates a graphical representation (300) depicting an input output relationship of dual and triple wave shaped control handle.

[0008] Figure 4 illustrates a block diagram depicting a control handle (400), which includes linear or non-linear potentiometer. The existing servo systems includes sensing elements in a control handle (400) for a rate command, where it has two standard potentiometers with analog input. These potentiometers are coupled mechanically to the palm grips and an output of which is an electrical signal proportional to the angle of tilt. The rate of movement of the servo systems/ drives is determined by the rate output of the control handle (400). There is a need for slow speed movement during tracking of a target or maximum speed movement during acquiring a new target is essential for servo systems. To incorporate this, performance of the cosine potentiometer/ custom defined sensors is built which are complex and costly.

[0009] Hence, there is a need of an apparatus for wave shaping of velocity commands for servo drives, which solves the above defined problems.

SUMMARY
[0010] This summary is provided to introduce concepts related to an apparatus and method for wave shaping of a velocity command. This summary is neither intended to identify essential features of the present invention nor is it intended for use in determining or limiting the scope of the present invention.

[0011] For example, various embodiments herein may include one or more apparatuses and methods for wave shaping of a velocity command are provided. In one of the embodiments, a method for wave shaping of a velocity command includes a step of sensing, by a plurality of sensors, movement of at least one drive. The method includes a step of identifying, by the sensors, position of the drive based on the sensed movement of the drive. The method includes a step of generating, by a control unit, a plurality of wave shape velocity commands based on the identified position. The method includes a step of mapping, by a mapping unit, the position with the velocity commands, and generating mapped data. The method includes a step of selecting, by a selection module, at least one wave shape velocity command based on the mapped data.

[0012] In another embodiment, an apparatus includes a plurality of sensors, a control unit, a mapping unit, and a selection module. The plurality of sensors is configured to sense movement of at least one drive, and identify position of the drive. The control unit is configured to generate a plurality of wave shape velocity commands based on the identified position. The mapping unit is configured to map the position with the velocity commands, and generate mapped data. The selection module is configured to select at least one wave shape velocity command based on the mapped data.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
[0013] The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference like features and modules.

[0014] Figure 1 illustrates a schematic diagram depicting input output relation of a linear potentiometer.

[0015] Figure 2 illustrates a schematic diagram depicting input output relation of a cosine potentiometer.

[0016] Figure 3 illustrates a graphical representation depicting input output relation of dual and triple wave shaped control handle.

[0017] Figure 4 illustrates a block diagram depicting an existing control handle.

[0018] Figure 5 illustrates a block diagram depicting an apparatus for wave shaping of a velocity command, according to an exemplary implementation of the present invention.

[0019] Figure 6 illustrates a block diagram depicting a programmable control handle, according to an exemplary implementation of the present invention.

[0020] Figure 7 illustrates a block diagram depicting a microcontroller printed circuit board (PCB), according to an exemplary implementation of the present invention.

[0021] Figure 8 illustrates a flowchart depicting a method for wave shaping of a velocity command, according to an exemplary implementation of the present invention.

[0022] It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative systems embodying the principles of the present invention. Similarly, it will be appreciated that any flowcharts, flow diagrams, and the like represent various processes which may be substantially represented in computer readable medium and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.

DETAILED DESCRIPTION
[0023] In the following description, for the purpose of explanation, specific details are set forth in order to provide an understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these details. One skilled in the art will recognize that embodiments of the present invention, some of which are described below, may be incorporated into a number of systems.

[0024] The various embodiments of the present invention provide an apparatus and method for wave shaping of a velocity command.

[0025] Furthermore, connections between components and/or modules within the figures are not intended to be limited to direct connections. Rather, these components and modules may be modified, re-formatted or otherwise changed by intermediary components and modules.
[0026] References in the present invention to “one embodiment” or “an embodiment” mean that a particular feature, structure, characteristic, or function described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.

[0027] In one of the embodiments, a method for wave shaping of a velocity command includes a step of sensing, by a plurality of sensors, movement of at least one drive. The method includes a step of identifying, by the sensors, position of the drive based on the sensed movement of the drive. The method includes a step of generating, by a control unit, a plurality of wave shape velocity commands based on the identified position. The method includes a step of mapping, by a mapping unit, the position with the velocity commands, and generating mapped data. The method includes a step of selecting, by a selection module, at least one wave shape velocity command based on the mapped data.

[0028] In another implementation, generating the velocity commands includes generating pre-defined wave shape or customized wave shape velocity commands.

[0029] In another implementation, the method includes moving the drive at one or more axes based on the velocity commands.

[0030] In another implementation, the method includes storing, in a database, the mapped data, and the pre-defined wave shape velocity commands.

[0031] In another implementation, selecting the velocity command includes selecting, by the selection module, at least one wave shape velocity command from the mapped data, dynamically.

[0032] In another implementation, the method includes converting, by a digital encoder, the received identified position to digital output.

[0033] In another implementation, the method includes generating, by a plurality of switches, fine low velocity commands for tracking control of the drives.

[0034] In another embodiment, an apparatus includes a plurality of sensors, a control unit, a mapping unit, and a selection module. The plurality of sensors is configured to sense movement of at least one drive, and identify position of the drive. The control unit is configured to generate a plurality of wave shape velocity commands based on the identified position. The mapping unit is configured to map the position with the velocity commands, and generate mapped data. The selection module is configured to select at least one wave shape velocity command based on the mapped data.

[0035] In another implementation, the control unit is configured to generate pre-defined wave shape or customized wave shape velocity commands.

[0036] In another implementation, the drive is configured to receive the velocity commands, and move at one or more axes based on the velocity commands.

[0037] In another implementation, the apparatus includes a database. The database includes one or more look up tables, which is configured to store the mapped data, and the pre-defined wave shape velocity commands.

[0038] In another implementation, the selection module is configured to dynamically select at least one wave shape velocity command from the mapped data.

[0039] In another implementation, the apparatus includes a digital encoder configured to convert the received identified position to digital output.

[0040] In another implementation, the drives are configured to receive the digital output by using the control unit.

[0041] In another implementation, the apparatus includes a plurality of switches. The switches are configured generate fine low velocity commands for tracking control of the drives.

[0042] In an embodiment, the present invention provides an apparatus which enables programmable wave shaping of velocity commands for servo drives and can be employed for multiple types of sensors and control interfaces.

[0043] In an embodiment, the apparatus provides the programmable wave shaping of velocity command for servo drives using linear potentiometer or encoders.

[0044] In an embodiment, the apparatus has a provision for selecting pre-defined wave shape or custom wave shape.

[0045] In an embodiment, the apparatus facilitates selection of wave shape by the user.

[0046] In an embodiment, the apparatus has a provision to provide Analog or Digital outputs.

[0047] In an embodiment, the apparatus can interface with standard sensors to eliminate the need for complex and costly wave shaped potentiometers.

[0048] In an embodiment, the apparatus gives a smooth and precise control of servo drives at lower speed, better dynamic and tracking control.

[0049] Figure 5 illustrates a block diagram depicting an apparatus for wave shaping of a velocity command, according to an exemplary implementation of the present invention.

[0050] An apparatus for wave shaping of a velocity command (hereinafter referred to as “apparatus”) (500) includes a plurality of sensors (502a, … 502n), a control unit (504), a mapping unit (506), and a selection module (508).

[0051] The plurality of sensors (502) is configured to sense movement of at least one drive, and identify the position of the drive. In an embodiment, the sensors (502) are coupled with the drive to sense different parameters of the drive, such as position, speed, location, and the like. The sensors (502) include Azimuth sensor, Elevation Sensor, Altitude Sensor, optical sensors, proximity sensors, and the like.

[0052] In an embodiment, the apparatus (500) includes a digital encoder (514). The digital encoder (514) is configured to cooperate with the sensors (502). The digital encoder (514) is configured to convert the received identified position to digital output, and transmits again to the sensors (502). The sensors (502) then transmits the digital output to the control unit (504) for further processing.

[0053] The control unit (504) is configured to cooperate with the sensors (502) to receive the identified position of the drive. The control unit (504) is configured to generate a plurality of wave shape velocity commands based on the identified position. In an embodiment, the control unit (504) can be a micro-controller. In an embodiment, the control unit (504) is configured to generate pre-defined wave shape or customized wave shape velocity commands. In another embodiment, the drive is configured to receive the velocity commands, and move at one or more axes based on the velocity commands. In one embodiment, the drives are configured to receive the digital output by using the control unit.

[0054] In an embodiment, the apparatus (500) includes a plurality of switches (510). The switches (510) are configured to cooperate with the control unit (504), and generate fine low velocity commands for tracking control of the drives, when the drive is moving at one or more axes.

[0055] The mapping unit (506) is configured to cooperate with the control unit (504) and the sensors (502) to receive the velocity commands, and the identified position, respectively. The mapping unit (506) is configured to map the identified position with the velocity commands, and generate mapped data.

[0056] The selection module (508) is configured to cooperate with the mapping unit to receive the mapped data. The selection module (508) is configured to select at least one wave shape velocity command based on the mapped data. In an embodiment, the selection module (508) is configured to dynamically select at least one wave shape velocity command from the mapped data.

[0057] In an embodiment, the apparatus (500) includes a database (512). The database (512) includes one or more look up tables configured to store the mapped data, and the pre-defined wave shape velocity commands. In an embodiment, the database (512) can be implemented as, but is not limited to, an enterprise database, a remote database, a local database, and the like. In one embodiment, the database (512) may themselves be located either within the vicinity of each other or may be located at different geographic locations. In another embodiment, the database (512) can be implemented inside or outside the apparatus (512) and the database (512) can be implemented as a single database.

[0058] Figure 6 illustrates a block diagram depicting a programmable control handle, according to an exemplary implementation of the present invention.

[0059] In Figure 6, a programmable control handle (600) includes a control handling interface card (602), a CAN connector (J2) (604), and encoders. In an embodiment, the control handling interface card (602) can be a micro-controller printed circuit board (PCB). Figure 7 illustrates a block diagram depicting a micro-controller printed circuit board (PCB), according to an exemplary implementation of the present invention.

[0060] A micro-controller (504) is configured to read a linear position transducer (Analog or Digital) and generate a wave shaped velocity command to the servo drives. The linear position is mapped to the velocity command in a lookup table stored in a database (512) or a micro-controller memory (not shown in figure). In an embodiment, the database (512) can hold multiple lookup table with predefined wave shape. The wave shape can be dynamically selected from a predefined pattern or loaded from an external device. Further, the micro-controller (504) and the circuits are realized within an existing space available, as shown in Figure 6.

[0061] In Figure 7, the position sensors (502a, 502b) are interfaced to the control handling interface card (602), as shown in Figure 6. The control handling interface card (602) is a micro-controller card and connected through Analog / High speed Serial Peripheral Interface (SPI) interface, as shown in blocks (704a, 704b). The micro-controller (504) interfaces with an analog position transducer (606a) or a digital encoder (606b), as shown in Figure 6. This position is passed into an indexed look up table based on selection from an operator. The output from the lookup table is then transmitted through the Controller Area Network (CAN) connector (604), over a Controller Area Network (CAN) / RS 232 / RS 422 (706, 708, 710) and as an analog output to the servo drives.

[0062] In an embodiment, the micro-controller (504) facilitates dynamic configuration of a lookup table from an external device over CAN network. The micro-controller (504) also has an interface with switches (510) to generate fine low velocity command for tracking control. The micro-controller (504) has interfaces with a grip switch to eliminate unintentional movement from the operator.
[0063] In an embodiment, the apparatus (500) uses a simple potentiometer or an encoder along with a micro-controller circuit to generate pre-defined/ user configurable wave shaped rate commands for use in servo drives. The output from the apparatus (500) can be configured for CAN/RS422/analog to meet the requirements. The apparatus (500) is developed as a cost effective replacement of a cosine potentiometer to generate command for servo drives.

[0064] Figure 8 illustrates a flowchart depicting a method for wave shaping of a velocity command, according to an exemplary implementation of the present invention.

[0065] The flowchart (800) starts at a step (802), sensing, by a plurality of sensors (502), movement of at least one drive. In an embodiment, a plurality of sensors (502) is configured to sense movement of at least one drive. At a step (804), identifying, by the sensors (502), position of the drive based on the sensed movement of the drive. In an embodiment, the sensors (502) are configured to identify position of the drive based on the sensed movement of the drive. At a step (806), generating, by a control unit (504), a plurality of wave shape velocity commands based on the identified position. In an embodiment, a control unit (504) is configured to generate a plurality of wave shape velocity commands based on the identified position. At a step (808), mapping, by a mapping unit (506), the position with the velocity commands, and generating mapped data. In an embodiment, a mapping unit (506) is configured to map the position with the velocity commands, and generate mapped data. At a step (810), selecting, by a selection module (508), at least one wave shape velocity command based on the mapped data. In an embodiment, a selection module (508) is configured to select at least one wave shape velocity command based on the mapped data.

[0066] It should be noted that the description merely illustrates the principles of the present invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present invention. Furthermore, all examples recited herein are principally intended expressly to be only for explanatory purposes to help the reader in understanding the principles of the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass equivalents thereof.
,CLAIMS:
1. A method for wave shaping of a velocity command, said method comprising:
sensing, by a plurality of sensors (502), movement of at least one drive;
identifying, by said sensors (502), position of said drive based on said sensed movement of said drive;
generating, by a control unit (504), a plurality of wave shape velocity commands based on said identified position;
mapping, by a mapping unit (506), said position with said velocity commands, and generating mapped data; and
selecting, by a selection module (508), at least one wave shape velocity command based on said mapped data.

2. The method as claimed in claim 1, wherein generating said velocity commands includes generating pre-defined wave shape or customized wave shape velocity commands.

3. The method as claimed in claim 2, wherein said method includes moving said drive at one or more axes based on said velocity commands.

4. The method as claimed in claim 1, wherein said method includes storing, in a database (512), said mapped data, and said pre-defined wave shape velocity commands.

5. The method as claimed in claim 1, wherein selecting said velocity command includes selecting, by said selection module (508), at least one wave shape velocity command from said mapped data, dynamically.

6. The method as claimed in claim 1, wherein said method includes converting, by a digital encoder (514), said received identified position to digital output.
7. The method as claimed in claim 1, wherein said method includes generating, by a plurality of switches (510), fine low velocity commands for tracking control of said drive.

8. An apparatus (500) for wave shaping of a velocity command, said apparatus (500) comprising:
a plurality of sensors (502) configured to sense movement of at least one drive, and identify position of said drive;
a control unit (504) configured to cooperate with said sensors (502), said control unit (504) configured to generate a plurality of wave shape velocity commands based on said identified position;
a mapping unit (506) configured to cooperate with said sensors (502) and said control unit (504), said mapping unit (506) is configured to map said position with said velocity commands, and generate mapped data; and
a selection module (508) configured to cooperate with said mapping unit (506), said selection module (508) configured to select at least one wave shape velocity command based on said mapped data.

9. The apparatus (500) as claimed in claim 8, wherein said control unit (504) is configured to generate pre-defined wave shape or customized wave shape velocity commands.

10. The apparatus (500) as claimed in claim 8, wherein said drive is configured to receive said velocity commands, and move at one or more axes based on said velocity commands.

11. The apparatus (500) as claimed in claim 1, wherein said apparatus (500) includes a database (512), said database (512) includes one or more look up tables configured to store said mapped data, and said pre-defined wave shape velocity commands.

12. The apparatus (500) as claimed in claim 8, wherein said selection module (508) is configured to dynamically select at least one wave shape velocity command from said mapped data.

13. The apparatus (500) as claimed in claim 8, wherein said apparatus (500) includes a digital encoder (514) configured to cooperate with said sensors (502), said digital encoder (514) is configured convert said received identified position to digital output.

14. The apparatus (500) as claimed in claim 8 or 13, wherein said drives are configured to receive said digital output by using said control unit (504).

15. The apparatus (500) as claimed in claim 8, wherein said apparatus (500) includes a plurality of switches (510), said switches (510) are configured to cooperate with said control unit (504), and generate fine low velocity commands for tracking control of said drives.