US-12625476-B2 - Control device

Abstract

A control device includes: a static compensator that calculates, on the basis of a static parameter, a static compensatory input; a dynamic compensator that calculates, on the basis of a dynamic parameter, a dynamic compensatory input; a subtractor that calculates an actual input by synthesizing the static compensatory input and the dynamic compensatory input; an ideal output calculator that calculates an ideal output responsive to a control input by using an input and output model defining an ideal input and output relation between a control input and a control output; and a parameter adjuster that adjusts the static parameter and the dynamic parameter to minimize a difference between the control output and the ideal output.

Inventors

• Shin WAKITANI
• Toru Yamamoto

Assignees

• HIROSHIMA UNIVERSITY
• KOBELCO CONSTRUCTION MACHINERY CO., LTD.

Dates

Publication Date

20260512

Application Date

20210929

Priority Date

20201120

Claims (2)

1. 1 . A control device that controls a controlled object, comprising: control circuitry configured to calculate a control input to eliminate an error between a target output and a control output which that is output from the controlled object; a static compensator circuit configured to calculate a static compensatory input to compensate for a fluctuation in static characteristics of the controlled object by multiplying the control input by a static gain; a dynamic compensator circuit configured to calculate, as a dynamic compensatory input a sum of a value obtained by multiplying the control output by a proportional gain and a value obtained by multiplying a differential value of the control output by a derivative gain to compensate for a fluctuation in dynamic characteristics of the controlled object; a synthesizer circuit configured to calculate, as an actual input, a value obtained by subtracting the dynamic compensatory input from the static compensatory input, and input the calculated actual input to the controlled object to control the controlled object; an ideal output calculator circuit configured to calculate an ideal output responsive to the control input by using an input and output model defining an ideal input and output relation between the control input and the control output; and a parameter adjuster circuit configured to adjust each of the static gain, the proportional gain, and the derivative gain by using recursive least squares to minimize a difference between the control output and the ideal output.
2. 2 . The control device according to claim 1 , wherein the controlled object includes a hydraulic system having a hydraulic pump; an electric motor that drives the hydraulic pump; and an actuator that comes into operation in response to hydraulic fluid supplied from the hydraulic pump, the hydraulic system outputting a state value of the actuator as the control output, and the synthesizer circuit is further configured to calculate an instructive value to the electric motor as the actual input.

Description

TECHNICAL FIELD The present invention relates to a control device that controls a controlled object. BACKGROUND ART A control device which controls a working machine, such as a hydraulic excavator, is demanded for a complicated control including an automatic operation. The control device demanded for the complicated control has a multi-layered control structure to activate a downstream control loop that directly controls a controlled object in accordance with an instruction from an upstream controller. However, a large fluctuation in input and output characteristics of the controlled object and a large fluctuation in input and output characteristics of the downstream control loop may impair appropriate operation of the upstream controller. Thus, the upstream controller fails to appropriately control the controlled object. Here, maintaining ideal input and output characteristics of the downstream loop succeeds in designing the upstream controller on the basis of the ideal input and output characteristics of the downstream control loop. Under the circumstances, a technology for suppressing a fluctuation in the input and output characteristics of the downstream control loop has been proposed. For instance, Non-patent Literature 1 discloses a control device including: an input and output model (Pm) indicating ideal input and output characteristics of a control input (u′) which is input from an upstream controller and a control output (y) which is output from a controlled object; a compensator (D) that generates a compensatory input (uc) for reducing a model error or difference between an ideal output (ym) of the input and output model (Pm) responsive to the control input (u′) and the control output (y); and a subtractor that calculates an actual input (u) to the controlled object by subtracting the compensatory input (uc) from the control input (u′). However, when the input and output characteristics of the controlled object largely fluctuate in the technology of Non-patent Literature 1, the compensator cannot sufficiently compensate the fluctuation. Hence, the upstream controller fails to appropriately control the controlled object. CITATION LIST Non-Patent Literature Non-patent Literature 1: Umei, Okajima, Matsunaga, and Asai (2014), “A design Method of Model Error Compensator for MIMO systems”, The Institute of Systems, Control and Information Engineers, Vol. 27, No. 2, PP. 67-72 SUMMARY OF INVENTION The present invention has been accomplished to solve the aforementioned drawbacks with an aim of providing a control device that achieves an appropriate control of a controlled object by using a controller in an initial design even when input and output characteristics of the controlled object largely fluctuate. A control device according to one aspect of the present invention is a control device that controls a controlled object. The control device includes: a controller that calculates a control input to eliminate an error between a target output and a control output which is output from the controlled object; a static compensator that calculates, on the basis of a static parameter and the control input, a static compensatory input to compensate a fluctuation in static characteristics of the controlled object; a dynamic compensator that calculates, on the basis of a dynamic parameter and the control output, a dynamic compensatory input to compensate a fluctuation in dynamic characteristics of the controlled object; a synthesizer that calculates an actual input by synthesizing the static compensatory input and the dynamic compensatory input, and inputs the calculated actual input to the controlled object; an ideal output calculator that calculates an ideal output responsive to the control input by using an input and output model defining an ideal input and output relation between the control input and the control output; and a parameter adjuster that adjusts each of the static parameter and the dynamic parameter to minimize a difference between the control output and the ideal output. This configuration achieves an appropriate control of the controlled object by using a controller in an initial design even when the input and output characteristics of the controlled object largely fluctuate. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a block diagram showing an example of a configuration of a control device according to an embodiment of the present invention. FIG. 2 is a flowchart showing an example of a process by the control device. FIG. 3 is a block diagram showing a feedback system constituting a control loop. FIG. 4 is a hydraulic circuit diagram of a hydraulic motor control system used as a controlled object. FIG. 5 includes graphs each showing a result of applying the control device to the hydraulic motor control system. FIG. 6 includes graphs respectively showing results of adjusting a static gain, a proportional gain, and a derivative gain. FIG. 7 includes enlarged graphs of the graphs in FIG. 6. DESCRIPTIO