Remote control system

Abstract

To enable disturbance compensation by separating a delay disturbance and a loss disturbance, in a remote control system via a communication network.SOLUTION: The present disclosure provides a remote control device including a measurement data receiving unit that receives measurement data measured by a control object from the control object, a delay measurement unit that measures a delay time of the measurement data received by the measurement data receiving unit, a delay disturbance calculation unit that calculates a delay disturbance included in the measurement data received by the measurement data receiving unit based on the delay time, a loss disturbance calculation unit that calculates a loss disturbance included in the measurement data received by the measurement data receiving unit, and a disturbance compensation unit that compensates for the delay disturbance and the loss disturbance in the measurement data using the delay disturbance and the loss disturbance.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to techniques for compensating for delays and information loss in remote control systems. [Background technology]

[0002] In remote feedback control of actuators such as motors via a communication network, communication delays and information loss adversely affect the stability and performance of the system. Techniques for compensating for communication delays have been proposed, including a Smith predictor using a constant communication delay model, an adaptive Smith predictor using an adaptive communication delay model based on round-trip time (RTT) measurements, and a communication disturbance observer (CDOB) that does not require a communication delay model. It has been suggested that a CDOB, in particular, can estimate and compensate for communication delays and information loss collectively as communication disturbances (see, for example, Non-Patent Documents 1 and 2). Furthermore, the placement of a controlled object model has also been studied as a method for configuring a CDOB for remote control via an unstable communication network where delay variations and information loss exist (see, for example, Non-Patent Document 3).

[0003] Conventional CDOB estimates and compensates for the effects of communication delays and information loss in communication networks collectively as disturbances on the system without distinguishing between them. However, conventional CDOB has the problem of being unable to separately estimate and compensate for delay disturbances and loss disturbances. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Ryogo Kubo and Kenji Natori, “Dependable networked motion control using communication disturbance observer,” Proceedings of the 27th International Technical Conference on Circuits / Systems, Computers and Communications (ITC-CSCC), D-T1-05, pp. 1-4, July 2012. [Non-patent document 2] Ryusuke Imai and Ryogo Kubo, “Experimental validation of communication disturbance observer for networked control systems with information losses,” IEICE Communications Express, vol. 5, no. 4, pp. 102-107, April 2016. [Non-patent document 3] T. Hyodo and K. Ohnishi, "Planning Method of Plant Model in Communication Disturbance Observer Considering Unstable Communication Networks," IEEJ Transactions on Systems Engineering, Vol. 135, No. 3, pp. 192-198, March 2015. Summary of the Invention [Problem to be solved by the invention]

[0005] The impact on system stability and performance differs between communication delays and information loss in a communication network. For this reason, it is desirable to compensate separately for system disturbances caused by communication delays (delay disturbances) and system disturbances caused by information loss (loss disturbances).

[0006] The present disclosure has been made in consideration of such problems, and an object of the present disclosure is to enable disturbance compensation by separating delay disturbance and loss disturbance in a remote control system via a communication network. [Means for solving the problem]

[0007] The remote control system of the present disclosure includes the remote control device of the present disclosure and a controlled object that receives the control data transmitted from the remote control device and operates in accordance with the control data.

[0008] The remote control device of the present disclosure includes: a measurement data receiving unit that receives measurement data measured by a control object from the control object; a delay measurement unit that measures a delay time of the measurement data received by the measurement data receiving unit; a delay disturbance calculation unit that calculates a delay disturbance included in the measurement data received by the measurement data receiving unit based on the delay time; a loss disturbance calculation unit that calculates a loss disturbance included in the measurement data received by the measurement data receiving unit; a disturbance compensation unit that compensates for delay disturbances and loss disturbances in the measurement data using the delay disturbances and the loss disturbances; a control unit that generates control data for controlling the controlled object based on the measurement data compensated for by the disturbance compensation unit; a control data transmission unit that transmits the control data generated by the control unit to the control target; Equipped with.

[0009] The remote control method of the present disclosure includes: a measurement data receiving unit receiving measurement data measured at a control object from the control object; a delay measurement unit that measures a delay time of the measurement data received by the measurement data receiving unit; a delay disturbance calculation unit calculates a delay disturbance included in the measurement data received by the measurement data receiving unit based on the delay time; a loss disturbance calculation unit that calculates a loss disturbance included in the measurement data received by the measurement data receiving unit; a disturbance compensation unit that compensates for delay disturbances and loss disturbances in the measurement data using the delay disturbances and the loss disturbances; a control unit generating control data for controlling the controlled object based on the measurement data compensated for by the disturbance compensation unit; A control data transmission unit transmits the control data generated by the control unit to the control target.

[0010] The program of the present disclosure is a program for causing a computer to execute each procedure included in the remote control method of the present disclosure.

[0011] The remote control device of the present disclosure may include a model unit that estimates the controlled object without considering a delay time included in the measurement data, and a delay model unit that estimates the controlled object while considering a delay time included in the measurement data. The delay disturbance calculation unit may calculate the delay disturbance included in the measurement data by comparing the state of the controlled object obtained by the model unit and the state of the controlled object obtained by the delay model unit.

[0012] The loss disturbance calculation unit may calculate the loss disturbance included in the measurement data by comparing an estimated value of the measurement data obtained by the delay model unit with the measurement data received by the receiving unit.

[0013] The delay measurement unit may measure the round-trip delay time by calculating the difference between the transmission time recorded in a packet to be transmitted to the control target and the reception time of the packet returned from the control target.

[0014] The delay measurement unit may measure the delay time by calculating a difference between a transmission time of the measurement data at the control target and a reception time of the measurement data at the measurement data receiving unit.

[0015] The above disclosures can be combined as much as possible. [Effects of the Invention]

[0016] According to the present disclosure, the delay disturbance and loss disturbance contained in the measurement data are calculated individually and used to compensate for the delay disturbance and loss disturbance in the measurement data, thereby enabling the delay disturbance and loss disturbance to be separated and disturbance compensation to be performed in a remote control system via a communication network. [Brief explanation of the drawings]

[0017] [Figure 1] 1 shows an example of the configuration of a remote control system. [Figure 2] 1 shows an example of a functional unit included in a remote control device. [Figure 3] 1 shows an example of a functional unit provided in a control target. [Figure 4] 1 shows an example of a functional unit included in a remote control device. [Figure 5] 1 shows an example of a functional unit included in a remote control device. [Figure 6] 1 illustrates an example embodiment of a remote control method according to the present disclosure. [Figure 7] 1 shows an example of a functional unit included in a remote control device. [Figure 8] 1 shows an example of a functional unit included in a remote control device. [Figure 9] 1 shows an example of a functional unit included in a remote control device. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below. These implementation examples are merely illustrative, and the present disclosure can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art. Note that components with the same reference numerals in this specification and drawings indicate the same components.

[0019] 1 shows an example of the configuration of a remote control system. The remote control system is configured by connecting a remote control device 92 and a controlled object 91 via a communication network 93. The controlled object 91 receives control data transmitted from the remote control device 92 and operates in accordance with the control data.

[0020] The communication network 93 between the remote control device 92 and the control target 91 may be a wired network or a wireless network as long as it is a network that allows information exchange. For example, it is conceivable to use a wireless LAN (Local Area Network) or a mobile communication network such as 5G.

[0021] The remote control device 92 is a digital computer such as a computer (including a server, personal computer, or microcomputer), and has a communication interface. The controlled object 91 can be any system having a sensor and an actuator, but for example, in a mechanical system such as a robot, an electric motor can be used as the actuator and an angle encoder can be used as the sensor. The controlled object 91 is equipped with a communication interface and a digital computer. Below, an example will be explained in which the remote control device 92 controls the angle of a motor provided in the controlled object 91.

[0022] A sensor on the control object 91 side, for example, an encoder for controlling the angle of a motor, transmits motor angle information as measurement data to a remote control device 92 at regular intervals via a communication network 93. The remote control device 92 then transmits the input value to the actuator, for example, the motor, as control data to the control object 91 at regular intervals via the communication network so that the received response signal converges to a target value. In addition to transmission delays, communication delays occur on the communication network 93 due to buffering delays and processing delays in the routers and switches that are relayed, and packet loss (information loss) due to buffer overflow may also occur. These communication delays and information loss are known to have a negative impact on the stability and performance of feedback control systems.

[0023] 2 and 3 show functional block diagrams of a remote control device 92 and a controlled object 91. The remote control device 92 is installed in a location physically separated from the controlled object 91, i.e., the motor, and the remote control device 92 is configured to control a target angle x cmd is input to the remote control device 92. The remote control device 92 includes a control unit 22, a control data transmission unit 23, and a measurement data reception unit 21.

[0024] The measurement data receiving unit 21 receives the motor angle response x res,r Receive the motor angle response x res,r is affected by communication delays and information loss in the communication network 93, and the motor angle response x transmitted from the controlled object 91 side res,r The information is delayed by the network delay, and if information loss occurs, the information does not exist. For example, the motor angle response x used by the control unit 22 at sampling time k (k is a positive integer) res,d [k] is the motor angle response x used one sampling time before when information loss occurs. res,d [k-1] can be used. The sampling period is set to be the same as the control period, for example.

[0025] The control unit 22 determines the target angle x cmd and motor angle response x res,d Based on the control data u ref For example, a PID (Proportional-Integral-Derivative) controller can be used as a general-purpose feedback controller to calculate the control data. The control data can be, for example, a reference voltage value or a reference current value to the motor. The control data transmission unit 23 receives the control data u ref U ref,s The control data u is transmitted to the control target 91. ref and u ref,s are the same value.

[0026] The controlled object 91 includes a control data receiving unit 11, a motor control unit 12, and a measurement data transmitting unit 13. The control data receiving unit 11 receives control data u ref,rThe motor control unit 12 drives the motor and measures the motor angle. The motor angle can be measured by any method, for example, an optical encoder can be used. The measurement cycle of the motor angle can be set arbitrarily, but can be set to the same cycle as the control cycle, for example. The measurement data transmission unit 13 receives the motor angle response x res x res.s to the remote control device 92.

[0027] Here, the control data u ref,r is affected by delays and information loss in the communication network, and the control data u transmitted from the remote control device 92 ref,s Therefore, the control data u actually input to the control object 91 at sampling time k (k is a positive integer) is ref,d When information loss occurs in [k], the motor control unit 12 uses the control data u used one sampling time before. ref,d [k-1] can be used. The sampling period is, for example, the same as the control period. The motor control unit 12 drives the motor and measures the motor angle at a constant period using an optical encoder or the like. For example, the measurement period of the motor angle is made to match the control period. The measurement data transmission unit 13 transmits the motor angle response x res x res,s The motor angle response x is transmitted to the remote control device 92. res and x res,s are the same value.

[0028] Hereinafter, a method for compensating for communication delays and information loss using CDOB will be described using the remote feedback control of a motor as an example. Figure 4 shows an example of the implementation of CDOB in a remote control device. CDOB 24 first calculates the motor angle response model x without using the communication network 93 using the controlled object model unit 41. m The controlled object model unit 41 may be a linear or nonlinear mathematical model that models the static and dynamic characteristics of the controlled object 91, or may be a simulation model or an algorithm.

[0029] CDOB24 is a motor angle response model x m and the motor angle response x actually received via the communication network 93 res,d The difference is calculated and filtered, and x cmp As a result, the communication disturbance output x cmp As for the filtering process, for example, when communication disturbance exists in the low frequency range, a low pass filter can be used to block noise in the high frequency range and perform disturbance compensation only in the low frequency range.

[0030] The disturbance compensation unit 26 calculates the output x of the CDOB 24. cmp The motor angle response x received by the measurement data receiving unit 21 is calculated using res,d For example, the disturbance compensation unit 26 compensates for the motor angle response x res,d Output to x cmp Add.

[0031] The CDOB 24 collectively estimates the delay disturbance caused by the communication delay on the communication network 93 and the loss disturbance caused by the information loss. res,d and output x cmp By adding the above, the delay disturbance and the loss disturbance can be offset. Therefore, when designing the remote control device 92, it is possible to reduce the influence of communication delays and information loss.

[0032] The conventional CDOB24 has the advantage of being able to estimate and compensate for delay disturbances and loss disturbances all at once without distinguishing between them. However, the causes of communication delays and information losses in communication networks93 are not necessarily the same, and the correlation between them cannot be said to be unique. Therefore, if it were possible to distinguish between delay disturbances and loss disturbances and then apply different filter processing to these disturbances, it would be effective in stabilizing control systems and improving their performance.

[0033] 5 shows a functional block diagram of a remote control device 92 according to the present disclosure. The CDOB 24 according to the present disclosure includes a controlled object model unit 41, a delay model unit 42, a delay measurement unit 43, a delay disturbance calculation unit 44, and a loss disturbance calculation unit 45. That is, the remote control device 92 according to the present disclosure includes a measurement data receiving unit 21, a delay measurement unit 43, a delay disturbance calculation unit 44, a loss disturbance calculation unit 45, a disturbance compensation unit 26, a control unit 22, and a control data transmission unit 23.

[0034] An embodiment of the remote control method of the present disclosure is shown in Figure 6. In the remote control method of the present disclosure, the remote control device 92 executes steps S11 to S16. In step S11, the measurement data receiving unit 21 receives measurement data measured by the control target 91 from the control target 91. In step S12, the delay measurement unit 43 measures the delay time of the measurement data received by the measurement data receiving unit 21. In step S13, the delay disturbance calculation unit 44 calculates the delay disturbance included in the measurement data received by the measurement data receiving unit 21 based on the delay time. In step S13, the loss disturbance calculation unit 45 calculates the loss disturbance included in the measurement data received by the measurement data receiving unit 21. In step S14, the disturbance compensator 26 compensates for the delay disturbance and the loss disturbance in the measurement data using the delay disturbance and the loss disturbance. In step S15, the control unit 22 generates control data for controlling the controlled object 91 based on the measurement data compensated for by the disturbance compensation unit . In step S16, the control data transmitting unit 23 transmits the control data generated by the control unit 22 to the controlled object 91.

[0035] The remote control device 92 of the present disclosure may include a controlled object model unit 41 and a delayed model unit 42. In this embodiment, the remote control device 92 calculates a delayed disturbance using the controlled object model unit 41, the delayed model unit 42, and the delayed disturbance calculation unit 44 in step S13.

[0036] Specifically, the controlled object model unit 41 estimates the controlled object 91 without considering the delay time included in the measurement data. The delay model unit 42 estimates the controlled object 91 with consideration of the delay time included in the measurement data. The delay disturbance calculation unit 44 calculates the delay disturbance included in the measurement data by comparing the states of the controlled object 91 obtained by the controlled object model unit 41 and the delay model unit 42.

[0037] Furthermore, in step S13, the loss disturbance calculation unit 45 calculates the loss disturbance contained in the measurement data by comparing the estimated value of the measurement data obtained by the delay model unit 42 with the measurement data received by the measurement data receiving unit 21. This makes it possible to calculate the loss disturbance from which the delay disturbance contained in the measurement data has been removed. This will be specifically described below with reference to FIG.

[0038] The controlled object model unit 41 is a motor angle response model x when not via the communication network 93. m The delay model unit 42 estimates the motor angle response model x when transmitted through the communication network 93 without information loss. m,d The calculation processing in the controlled object model unit 41 and the delayed model unit 42 can use, for example, a linear or nonlinear mathematical model that models the static characteristics and dynamic characteristics of the controlled object 91, and is not limited to a mathematical model, but may also be a simulation model or an algorithm.

[0039] The delay measurement unit 43 measures a communication delay that occurs when control data is transmitted from the remote control device 92 to the control target 91 and a communication delay time that occurs when measurement data is transmitted from the control target 91 to the remote control device 92. For example, the delay measurement unit 43 measures the RTT between the remote control device 92 and the control target 91 by calculating the difference between the transmission time recorded in a packet transmitted to the control target 91 and the reception time of the packet returned from the control target 91.

[0040] Furthermore, when time synchronization is established with the control target 91 side, the delay measurement unit 43 may measure the return delay time by calculating the difference between the transmission time of the measurement data in the control target 91 and the reception time of the measurement data in the measurement data receiving unit 21, and may further measure the outbound delay time by calculating the difference between the return delay and the RTT. In this case, as shown in FIG. 7, the delay model unit 42 may include an outbound delay model unit 42F and a return delay model unit 42B. The outbound delay model unit 42F delays an input signal by the amount of the outbound delay from the remote control device 92 to the control target 91, and outputs the delayed signal. The return delay model unit 42B delays an input signal by the amount of the return delay from the control target 91 to the remote control device 92, and outputs the delayed signal. As a result, a motor angle response model x is obtained as a result of control data passing through the outbound delay, the control target 91, and the return delay in this order, just like in an actual communication network 93. m,d Therefore, it is desirable to configure the delay model unit 42 as shown in Fig. 7. Note that the method for measuring the delay is arbitrary.

[0041] The delay model unit 42 is a model that reproduces the delay including fluctuations in the communication network 93 and the controlled object 91, but there are cases where the delay measurement unit 43 can only measure the RTT. In such cases, the delay model unit 42 may have an RTT delay model unit 42R disposed before the controlled object model unit 41 as shown in Fig. 8, or may have an RTT delay model unit 42R disposed after the controlled object model unit 41 as shown in Fig. 9.

[0042] The delay disturbance calculation unit 44 estimates the delay disturbance. For example, the delay disturbance calculation unit 44 calculates the delay disturbance by calculating the motor angle response model x m and motor angle response model x m,d The difference between the motor angle response model x and the motor angle response model x is calculated, and then filtered by the first filter processing unit. m is a model that does not use the communication network 93, and the motor angle response model x m,d is a model in the case of a communication network 93 without information loss. Therefore, the first output x obtained by the delay disturbance calculation unit 44 is cmp,dis a delay disturbance that is an estimate of the communication delay on the communication network 93 in the angle dimension.

[0043] The loss disturbance calculation unit 45 estimates the loss disturbance. For example, the loss disturbance calculation unit 45 calculates the motor angle response model x m,d and motor angle response x res,d The difference between the motor angle response model x and the motor angle response model x is calculated, and then filtered by the second filter processing unit. m,d is the case when the communication network is free of information loss, and the motor angle response x res,d is a value actually received via the communication network. Therefore, the second output x obtained by the loss disturbance calculation unit 45 is cmp,l is a loss disturbance that estimates the information loss on the communication network 93 in the angle dimension.

[0044] The disturbance compensation unit 26 calculates the motor angle response x received by the measurement data receiving unit 21. res,d is compensated for by the disturbance calculated by CDOB24. For example, CDOB24 compensates for the first output x cmp,d and the second output x cmp,l The sum of these is calculated and the resulting output is x cmp The disturbance compensation unit 26 outputs the motor angle response x res,d Output to x cmp This gives the motor angle response x res,d The delayed disturbance and loss disturbance are compensated for in the motor angle response x res,d is input to the control unit 22. Therefore, the present disclosure makes it possible to reduce the influence of communication delays and information loss when designing the remote control device 92.

[0045] The first filter processing unit provided in the delay disturbance calculation unit 44 and the second filter processing unit provided in the loss disturbance calculation unit 45 use a low-pass filter that passes the corresponding low frequency range when the delay disturbance or loss disturbance exists in the low frequency range, and can block noise in the high frequency range and perform disturbance compensation only in the low frequency range.

[0046] In the present disclosure, the cutoff frequencies of the first filtering section and the second filtering section can be set to different values ​​depending on the frequency characteristics of the delay disturbance and the loss disturbance. Also, different types of filters can be used for the first filtering section and the second filtering section. For example, the first filtering section and the second filtering section can be arbitrarily selected from frequency filters such as a low-pass filter, a high-pass filter, a band-pass filter, and a band-stop filter.

[0047] As described above, the remote control device 92 measures the RTT of the communication network 93 between the remote control device 92 and the controlled object 91, and can estimate the delay disturbance and the loss disturbance separately using an adaptive communication delay model, thereby making it possible to perform different filter processing on the delay disturbance and the loss disturbance.

[0048] (Other embodiments) The remote control device 92 of the present invention can also be realized by a computer and a program, and the program can be recorded on a recording medium or provided via a communication network. The program of the present disclosure is a program for causing a computer to realize each function of the remote control device 92 according to the present disclosure, and is a program for causing a computer to execute each procedure of the method executed by the remote control device 92 according to the present disclosure. [Explanation of symbols]

[0049] 11: Control data receiver 12: Motor control unit 13: Measurement data transmission unit 21: Measurement data receiving unit 22: Control unit 23: Control data transmission unit 24:CDOB 26: Disturbance compensation section 41: Control object model part 42: Delayed model part 43: Delay measurement unit 44: Delay disturbance calculation unit 45: Loss disturbance calculation section 91: Control target 92: Remote control device 93: Communication Network

Claims

1. a measurement data receiving unit that receives measurement data measured by a control object from the control object; a delay measurement unit that measures a delay time of the measurement data received by the measurement data receiving unit; a delay disturbance calculation unit that calculates a delay disturbance included in the measurement data received by the measurement data receiving unit based on the delay time; a loss disturbance calculation unit that calculates a loss disturbance included in the measurement data received by the measurement data receiving unit; a disturbance compensation unit that compensates for the delay disturbance and the loss disturbance in the measurement data using the delay disturbance and the loss disturbance; a control unit that generates control data for controlling the controlled object based on the measurement data compensated for by the disturbance compensation unit; a control data transmission unit that transmits the control data generated by the control unit to the control target; A remote control device comprising:

2. a model unit that estimates the controlled object without taking into account the delay time included in the measurement data; a delay model unit that estimates the control target taking into account the delay time included in the measurement data; and Equipped with the delay disturbance calculation unit calculates the delay disturbance included in the measurement data by comparing the state of the control object obtained by the model unit and the state of the control object obtained by the delayed model unit. The remote control device of claim 1 .

3. the loss disturbance calculation unit calculates the loss disturbance included in the measurement data by comparing the estimated value of the measurement data obtained by the delay model unit with the measurement data received by the measurement data receiving unit. The remote control device according to claim 2 .

4. The delay measurement unit measures a round-trip delay time by calculating a difference between a transmission time recorded in a packet to be transmitted to the control target and a reception time of the packet returned from the control target. The remote control device of claim 1 .

5. The delay measurement unit measures the delay time by calculating a difference between a transmission time of the measurement data at the control target and a reception time of the measurement data at the measurement data receiving unit. The remote control device of claim 1 .

6. A remote control device according to any one of claims 1 to 5; the controlled object that receives the control data transmitted from the remote control device and operates in accordance with the control data; A remote control system comprising:

7. a measurement data receiving unit receiving measurement data measured at a control object from the control object; a delay measurement unit that measures a delay time of the measurement data received by the measurement data receiving unit; a delay disturbance calculation unit calculates a delay disturbance included in the measurement data received by the measurement data receiving unit based on the delay time; a loss disturbance calculation unit that calculates a loss disturbance included in the measurement data received by the measurement data receiving unit; a disturbance compensation unit that compensates for the delay disturbance and the loss disturbance in the measurement data using the delay disturbance and the loss disturbance; a control unit generating control data for controlling the controlled object based on the measurement data compensated for by the disturbance compensation unit; a control data transmission unit that transmits the control data generated by the control unit to the control target; Remote control method.

8. a measurement data receiving unit receiving measurement data measured by a control object from the control object; a delay measurement unit measuring a delay time of the measurement data received by the measurement data receiving unit; a delay disturbance calculation unit calculating a delay disturbance included in the measurement data received by the measurement data receiving unit based on the delay time; a step in which a loss disturbance calculation unit calculates a loss disturbance included in the measurement data received by the measurement data receiving unit; a disturbance compensation unit compensating for the delay disturbance and the loss disturbance in the measurement data using the delay disturbance and the loss disturbance; a step in which a control unit generates control data for controlling the controlled object based on the measurement data compensated for by the disturbance compensation unit; a control data transmitting unit transmitting the control data generated by the control unit to the control target; A program that causes a computer to execute the following.

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