Robot Drive Device Disturbance Control

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Solution Overview

Problem

Existing robot drive systems face instability in position control and torque control due to high variation in input torque and frequency when the robot arm contacts or collides with objects, limiting the use of control parameters.

Innovation Solution

A robot drive device with a motor drive circuit, a control instruction value generation unit, and a correction processing unit that applies a position control method to low-frequency disturbance components and a virtual spring constant control method to high-frequency disturbance components, thereby correcting the position target value and virtual spring constant in synchronized cycles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the virtual spring constant is set to be relatively high to ensure position control precision, then position control precision is improved, but vibration occurs and target position variation becomes difficult

Engineering Contradiction:

Improveposition control precisionVSAvoidvibration

Core Design Contradiction:

Measurement precisionVSStability of the object's composition

Solution Approach 1:

The patent segments the disturbance components into low-frequency and high-frequency parts, applying different control methods to each segment. The position control method is applied to low-frequency disturbances while the virtual spring constant control method is applied to high-frequency disturbances, allowing the system to achieve both precision and stability without vibration

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent dynamically adjusts the control parameters (position target value and virtual spring constant) based on the frequency characteristics of disturbances. The correction processing unit modifies these parameters in real-time during cyclic processes, enabling the system to adapt to varying disturbance conditions and maintain optimal performance

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If the virtual spring constant is set to a high value to improve position control precision, then position control precision is improved, but the control parameters become limited and cannot be varied sufficiently

Engineering Contradiction:

Improveposition control precisionVSAvoidcontrol parameter flexibility

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic adjustment of control parameters through the correction processing unit that operates in synchronized cycles with the control instruction value generation unit. This allows the virtual spring constant and position target value to be varied sufficiently based on actual disturbance conditions while maintaining position control precision

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the control parameters (position target value and virtual spring constant) based on the frequency characteristics of disturbances. By detecting whether disturbances are low-frequency or high-frequency and adjusting parameters accordingly, the system achieves both precision and adaptability

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If position control method is applied to all disturbances, then position control precision is improved, but high-frequency disturbances cannot be effectively suppressed

Engineering Contradiction:

Improveposition control precisionVSAvoidhigh-frequency disturbance

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent segments disturbances by frequency and applies specialized control methods to each segment. The position control method handles low-frequency disturbances while the virtual spring constant control method specifically addresses high-frequency disturbances, effectively suppressing harmful high-frequency effects while maintaining precision

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The correction processing unit acts as an intermediary that detects disturbance frequency characteristics and selects the appropriate control method. This intermediary component enables the system to respond appropriately to different types of disturbances, preventing high-frequency vibration while maintaining position control precision

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20250033198A1Robot drive device, robot drive method, non-transitory storage medium

Publication Date: 2025.01.30 TOYOTA JIDOSHA KK

AI summary

A device includes: a motor drive configured to increase and decrease a drive current according to a control instruction value and to output a position present value corresponding to a rotational angle of a motor, the drive current being provided to the motor attached to a joint of a robot; a control instruction value generation unit configured to generate the control instruction value; and a correction processing unit configured to output a corrected position target value and a corrected virtual spring constant to the control instruction value generation unit in cycles synchronized with cyclic processes of the control instruction value generation unit. The correction processing unit is configured to perform a correction process in which a position control method is applied to a low-frequency disturbance component, among disturbances provided to the motor, and in which a virtual spring constant control method is applied to a high-frequency disturbance component.