Control device and control method

Abstract

To prevent deterioration of operability due to communication delays.SOLUTION: A control device includes: a feedback control unit that receives a control target and outputs a control command to a control object so as to reduce a deviation between the control target and a control state of the control object; and a correction unit that corrects the control command output from the feedback control unit to accelerate the response of the control object to changes in the control target.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a control device and a control method. [Background technology]

[0002] In recent years, technological development of next-generation mobile communication systems is expanding from mobile applications to industrial applications. Three features are proposed for next-generation mobile communication systems: ultra-high speed and large capacity, multiple simultaneous connections, and ultra-reliable low latency. Low latency is particularly important for realizing remote motion control of IoT (Internet of Things) terminals.

[0003] However, in general wireless transmission and reception, the greater the number of communication devices between the apparatus to be controlled and the device operated by the person, the greater the delay in network communication. For this reason, for example, Patent Document 1 proposes a control system that compensates for communication delays using a Smith predictor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-9740 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology of Patent Document 1 requires that an accurate delay time be given to the Smith predictor before transmission, so it is not easy for companies that do not have accurate prediction technology to use it. In addition, a large communication delay deteriorates operability for the operator, but the technology of Patent Document 1 does not mention improving operability.

[0006] Therefore, an object of the present invention is to suppress deterioration of operability due to communication delays. [Means for solving the problem]

[0007] In order to solve the above problem, a control device according to one embodiment of the present invention includes a feedback control unit that receives a control target and outputs a control command to the control object so as to reduce the deviation between the control target and a control state of the control object, and a correction unit that corrects the control command output from the feedback control unit to accelerate the response of the control object to changes in the control target.

[0008] According to such a control device, the correction section accelerates the response of the controlled object, so that communication delays appear smaller and deterioration of operability is suppressed. In the control device, it is preferable that the correction unit corrects the control command using feedforward control. The correction unit may adopt, for example, model predictive control, but when the correction unit uses feedforward control, it has a high affinity with feedback control and can smoothly accelerate the response of the controlled object.

[0009] In the control device, the correction unit may include a trajectory correction unit that corrects the trajectory represented by the control target, and a feedforward control unit that performs feedforward control based on the corrected trajectory. By correcting the trajectory of the control target by the trajectory correction unit, appropriate feedforward control can be easily obtained.

[0010] It is further preferable that the control device further comprises a delay measurement unit that measures a communication delay in the control target input via a communication network, and the correction unit accelerates the reaction of the control target to an extent that compensates for the measured communication delay. By providing the delay measurement unit, it becomes possible to quickly respond even when a large fluctuation in communication delay occurs or when the location of the operating side that sends the control target is changed between a remote location and a nearby location. In the control device, the correction unit may accelerate a response of the controlled object when the measured communication delay exceeds a predetermined threshold.

[0011] In order to solve the above problem, a control method according to one embodiment of the present invention includes a feedback control step in which a control target is input and a control command is output to the control target so as to reduce a deviation between the control target and a control state of the control target, and a correction step in which the control command output in the feedback control step is corrected to accelerate a response of the control target to a change in the control target.

[0012] According to such a control method, the reaction of the controlled object is accelerated in the correction step, so that the communication delay appears smaller and deterioration of operability is suppressed. Effect of the Invention

[0013] According to the present invention, it is possible to suppress deterioration of operability due to communication delays. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram showing a remote control system to which an embodiment of the present invention is applied. [Diagram 2] FIG. 2 is a diagram showing a comparative example for the remote control system shown in FIG. [Diagram 3] 1 is a graph showing an example of the effect of communication delay; [Figure 4] FIG. 2 is a diagram showing a configuration of a remote device according to the present embodiment. [Diagram 5] FIG. 2 is a diagram illustrating a configuration of a position control unit. [Figure 6] FIG. 13 is a diagram illustrating an example of trajectory correction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, in order to avoid the following description becoming unnecessarily redundant and to facilitate understanding by those skilled in the art, more detailed description than necessary may be omitted. For example, detailed description of already well-known matters and duplicated description of substantially the same configuration may be omitted. In addition, elements shown in the previously described figures may be appropriately referenced in the description of the later figures.

[0016] <Remote control system> FIG. 1 is a diagram showing a remote control system 1 to which one embodiment of the present invention is applied. The remote control system 1 includes an operating side device 10, a communication network 20, and a remote side device 30.

[0017] The operating side device 10 outputs a control target value for operating the remote side device 30. The operating side device 10 includes, for example, a controller 11 that calculates a control target value based on a program or the like, and an operation device 12 that receives an operation by an operator and outputs a control target value corresponding to the operation. Specific shapes of the operation device 12 include, for example, a joystick 12a and a steering wheel 12b. The operating side device 10 may be a composite device in which the operation device 12 and the controller 11 are combined.

[0018] The operating side device 10 outputs a control target value for at least one of the position, angle, force, and torque in the remote side device 30. The position, angle, force, and torque are control amounts required for practical purposes such as the operation of the remote side device 30, and are suitable as control targets. In the following, a representative example will be described in which the control target value of angle is adopted.

[0019] The communication network 20 is, for example, a network such as 5G or LPWA (Low Power Wide Area), and transmits a control target value (target angle) output by the operating side device 10 to the remote side device 30. The remote device 30 is a device that operates according to a control target value. The remote device 30 includes, for example, a laboratory device 31 and a heavy machine 32, as well as a transport robot, a surgical robot, a machine tool, an XY table, and the like.

[0020] The remote device 30 has an actuator, such as a motor or a hydraulic device, and a mechanical part driven by the actuator. A control unit is incorporated in the actuator of the remote device 30, which receives a control target value for an angle and realizes the angle indicated by the control target value. The control unit corresponds to one embodiment of the control device of the present invention, and the mechanical part corresponds to an object to be controlled by the control device. The configuration of the control unit will be described in detail later.

[0021] In the remote device 30, the angle, torque, and the like generated in the mechanism as a result of the actuator drive are detected by a sensor or calculated as state quantities representing the control state. The detected or calculated state quantities are used for control by a position control unit incorporated in the actuator, and are also returned to the operating side via the communication network 20 as monitor values ​​of the remote device 30.

[0022] When operating the remote device 30 in the remote operation system 1, a communication delay occurs for the outbound path of the communication network 20, and when monitoring the control state of the remote device 30, a communication delay occurs for the return path of the communication network 20.

[0023] <Comparative Example> FIG. 2 is a diagram showing a comparative example to the remote control system 1 shown in FIG. The remote side of the comparative example is provided with a position control unit 40 and a mechanism unit 36. The position control unit 40 controls an actuator (not shown), and the mechanism unit 36 ​​is driven by the actuator. The controlled object in the comparative example is the mechanism unit 36, and as an example, the output angle θ of the mechanism unit 36 ​​is controlled. The characteristic of the mechanism unit 36 ​​is, for example, 1 / (Js 2 +Bs), where J is the inertia of the mechanical part 36 and B is the viscous friction of the mechanical part 36. Furthermore, the position control unit 40 performs control based on a control model C(s).

[0024] In the comparative example, the target angle θ ** is sent to the remote side via the communication network 20. A communication delay 22 occurs in the communication network 20, and the target value θ **is the target value θ delayed by the delay time td2 as shown in the following equation (1). * It reaches the remote side as

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[0025] The position control unit 40 receives a target angle θ * and the monitored value of the output angle θ in the mechanical part 36 are input, and the position control part 40 performs feedback control to reduce the difference, thereby reducing the output torque T * The output torque T generated by the actuator is controlled. * A disturbance torque Td is added to

[0026] The mechanical part 36 is driven by the torque to which the disturbance torque Td is added, and the mechanical part 36 outputs an angle θ. The output angle θ of the mechanical part 36 is monitored by a sensor or the like, and the monitored value is fed back to the position control part 40. The monitor value of the output angle θ is sent to the operating side via the communication network 20. A return communication delay 21 occurs in the communication network 20, and the monitor value of the output angle θ arrives at the operating side with a delay of a delay time td1.

[0027] The operator observes the state (output angle θ) of the remote side from the monitor value received via the communication network 20, but the state observable on the operating side is delayed by a delay time td1 compared to the remote side. In general, it is said that operability deteriorates when the delay time from operation to observation exceeds 200 [ms].

[0028] FIG. 3 is a graph showing an example of the effect of communication delay. The horizontal axis of FIG. 3 indicates time, and the vertical axis indicates angle. The feedback control by the position control unit 40 is designed so that the output angle follows the command, for example, in about 150 [ms] after the target angle value is input. Therefore, the target angle value θ **reaches position control unit 40 without delay, the output angle changes as shown by the response waveform indicated by the solid line in the graph.

[0029] On the other hand, if the delay time td2 in the outbound communication delay 22 is, for example, 50 [ms], the output target value θ ** The target value θ reached for * is delayed by 50 ms. As shown by the dotted line in the graph, the response waveform of the output angle is also shifted 50 ms to the right compared to the case without delay.

[0030] The response waveform of the output angle observed by the operator is a waveform that is further time-shifted to the right by about 50 [ms] due to the return communication delay 21. Therefore, if the communication delay time is large, the deviation of the output angle from the operation increases and exceeds 200 [ms], resulting in a deterioration of operability.

[0031] <Embodiment> In contrast to the comparative example described above, a control unit corresponding to one embodiment of a control device of the present invention performs control to suppress deterioration of operability. FIG. 4 is a diagram showing a configuration of the remote device 30 of this embodiment. The remote device 30 includes a mechanism 36 to be controlled, and a control unit 50 that controls the output angle of the mechanism 36. In this embodiment, the control unit 50 is described as being incorporated in an actuator (not shown), but the control unit 50 may be provided independently of the actuator.

[0032] The control unit 50 includes a delay measurement unit 33, a trajectory correction unit 34, and a position control unit 35. The delay measurement unit 33 measures the target value θ * The delay time td2 is measured by receiving the signal from the control unit 10 and measuring the delay time td2 in the communication delay 22. For example, the delay time td2 is measured by setting a target value θ **A method can be adopted in which a time stamp is added to the received target value θ * is input to the position control unit 35, and the trajectory correction unit 34 receives the target value θ * The measured delay time td2 is input.

[0033] When the delay time td2 exceeds a predetermined threshold, the trajectory correction unit 34 adjusts the target value θ * A corrected trajectory is calculated for the trajectory indicated by the * is input together with flag Ft to position control unit 35. Flag Ft indicates that delay time td2 has exceeded a threshold value and the trajectory has been corrected.

[0034] When the remote side device 30 is connected to the operating side device 10, for example, by direct wireless communication instead of the communication network 20, or when the operating side device 10 and the remote side device 30 are connected via a part of the communication network 20 with little delay, the delay time td2 is short and does not exceed the threshold value, so that the trajectory correction unit 34 does not perform trajectory correction.

[0035] The monitor value of the output angle θ is also input to the position control section 35, and the monitor value is also sent to the operating side via the communication network 20. FIG. 5 is a diagram showing the configuration of the position control unit 35. The position control unit 35 includes a feedback controller 37 and a feedforward controller 38 .

[0036] The feedback controller 37 receives the target angle value θ * and the monitored value of the output angle θ in the mechanism portion 36 are input, and the feedback controller 37 performs feedback control to reduce the difference, thereby reducing the output torque T * Control.

[0037] On the other hand, the feedforward controller 38 receives a corrected target value θm* When the flag Ft indicating that the trajectory has been corrected is input, the feedforward controller 38 calculates the corrected target value θm * The amount of feedforward compensation based on the above is calculated to correct the output from the feedback controller 37. The trajectory correction by the trajectory correction unit 34 and the feedforward controller 38 is performed based on the target value θ of the output angle θ by the feedback control of the feedback controller 37. * As a result, the reaction to the target object is accelerated. That is, the trajectory correction unit 34 and the feedforward controller 38 function together as a correction unit that accelerates the reaction of the target object.

[0038] In addition, if the delay time td2 is short and does not exceed the threshold, the flag Ft is not input to the feedforward controller 38, so that the eye position control unit 35 does not detect the target value θ * Therefore, only feedback control based on the above is performed. <Trajectory correction> The trajectory correction unit 34 generates the trajectories of the state variables θ, ω, and γ by solving the state equation shown in the following equation (2) with the boundary condition shown in the following equation (3). As a result, the corrected target value θm * is obtained.

[0039]

number

[0040]

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[0041] In solving the state equation of formula (2), the trajectory correction unit 34 is given an evaluation function shown in formula (4) below.

number

[0042] By setting three types of weights Q, R, and S in the evaluation function K, a corrective trajectory that accelerates the response of the output angle θ can be obtained. The trajectory correction is calculated for each sample period of communication. However, if the Riccatti matrix differential equation shown in equation (4) is calculated as is, the calculation time may not fit within the sample period, so the corrected trajectory may be calculated using, for example, an approximate polynomial.

[0043] Fig. 6 is a diagram showing an example of trajectory correction, in which the horizontal axis indicates time and the vertical axis indicates angle. In FIG. 6, similarly to FIG. 3, a response waveform without delay is indicated by a solid line, and a response waveform in a comparative example in which the delay time td2 is, for example, 50 [ms] is indicated by a dotted line. In contrast, when the delay time td2 is, for example, 50 [ms], the corrected target value θm * The response waveform shown by the dashed and dotted line is a waveform obtained when feedforward control is performed based on the target value θ * In this way, the time rise time for the input of the corrected target value θm * The reaction of the output angle θ is accelerated by the feedforward control using the above method, thereby suppressing the deterioration of operability due to communication delays.

[0044] If the response of the output angle θ is accelerated when there is no communication delay, the response becomes too sensitive, which in turn leads to deterioration of operability. For this reason, it is preferable that a delay measurement unit 33 is provided as shown in Fig. 4, and that the trajectory correction unit 34 and the feedforward controller 38 perform trajectory correction when the delay time td2 exceeds a predetermined threshold. Also, if the trajectory correction unit 34 and the feedforward controller 38 perform excessive trajectory correction, the response becomes too sensitive as well, so it is preferable that the trajectory correction unit 34 and the feedforward controller 38 accelerate the response of the controlled object to an extent that compensates for the measured communication delay.

[0045] Further, in the above description, an example has been shown in which correction is performed by feedforward control, but the correction unit according to the present invention may perform correction by, for example, model predictive control. [Explanation of symbols]

[0046] 1... remote control system, 10... operating side device, 11... controller, 12... operating device, 12a... joystick, 12b... steering, 20... communication network, 30: remote device; 31: laboratory device; 32: heavy machinery; 33: delay measurement unit; 34... trajectory correction unit, 35... position control unit, 36... mechanical part, 37... feedback controller, 38...Feedforward controller

Claims

1. a feedback control unit that receives a control target and outputs a control command to the controlled object so as to reduce a deviation between the control target and a control state of the controlled object; a correction unit that corrects the control command output from the feedback control unit to accelerate the response of the controlled object to a change in the control target; A control device comprising:

2. The control device according to claim 1 , wherein the correction unit corrects the control command by using feedforward control.

3. The control device according to claim 2 , wherein the correction unit includes a trajectory correction unit that corrects the trajectory represented by the control target, and a feedforward control unit that performs feedforward control based on the corrected trajectory.

4. The method further includes the step of: measuring a communication delay in the control target input via a communication network; The control device according to claim 1 , wherein the correction unit accelerates a response of the controlled object to an extent that compensates for the measured communication delay.

5. The control device according to claim 4 , wherein the correction unit accelerates a response of the controlled object when the measured communication delay exceeds a predetermined threshold.

6. a feedback control step of receiving a control target and outputting a control command to the controlled object so as to reduce a deviation between the control target and a control state of the controlled object; a correction step of correcting the control command outputted in the feedback control step to accelerate a response of the controlled object to a change in the control target; The control method includes:

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