Host-Side Model Feedback for Robot Trajectory Tracking

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Solution Overview

Problem

Conventional control systems for trajectory tracking in robots face challenges in achieving effective trajectory tracking capability due to response delays and varying trajectory properties, requiring user-adjusted delay times to correct position commands, which increases the user's adjustment load.

Innovation Solution

A control system configuration with a host-side control device that models the drive-side feedback system, allowing for correction of operation command signals using feedback from the drive-side feedback system and control target, thereby enhancing trajectory tracking capability without the need for user-adjusted delay times.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a position model is used to estimate future position and correct position command, then trajectory tracking capability is improved, but user adjustment load increases due to requiring delay time adjustment

Engineering Contradiction:
Improvetrajectory tracking precisionVSAvoiduser adjustment load
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The control system performs self-adjustment by automatically determining the delay time based on the transfer function of the control target. The correction amount calculation unit computes the delay time τ by analyzing the system's frequency characteristics, eliminating the need for manual user adjustment while maintaining optimal trajectory tracking precision.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system uses feedback from the control target's actual response to automatically determine the optimal delay time. By measuring the transfer function and analyzing the frequency characteristics, the system self-adjusts the delay parameter to match the actual system behavior, resolving the contradiction between precision and ease of operation.

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If delay time is adjusted to improve trajectory tracking, then tracking precision is improved, but system complexity increases

Engineering Contradiction:
Improvetrajectory tracking precisionVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system automatically determines the delay time through self-diagnosis of its own transfer function characteristics. This self-service approach eliminates the need for external manual adjustment mechanisms, keeping the system structure simple while achieving precise trajectory tracking through automated parameter determination.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If feed-forward control is used to eliminate response delay, then trajectory tracking capability is improved, but adaptability to trajectory property changes deteriorates

Engineering Contradiction:
Improvetrajectory tracking capabilityVSAvoidadaptability to trajectory property changes
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The system dynamically adapts to changing trajectory properties by continuously determining the delay time based on the actual transfer function. When trajectory properties change (e.g., from linear to arc movement), the system recalculates the optimal delay parameter, maintaining high tracking precision across different motion types without requiring manual reconfiguration.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3598248B1Control system
Publication Date: 2022.04.06 OMRON CORP
  • EP3598248B1 patent drawingFigure 1
  • EP3598248B1 patent drawingFigure 2
  • EP3598248B1 patent drawingFigure 3

AI summary

A control system provided with a drive-side control device and a host-side control device, wherein: the drive-side control device has a drive-side control structure, which includes a drive-side feedback system and a drive-side control model unit and which is configured so as to enable model tracking control in accordance with a control model provided to the drive-side control model unit; and the host-side control device has a host-side control structure, which includes a host-side control model unit in which the drive-side feedback system and a control subject are modeled, and which is configured so that a host-side corrective signal based on the deviation between the output of the host-side control model unit and an operation command signal is fed back to the input side of the host-side control model unit, and a corrected command signal generated on the basis of the fed-back host-side corrective signal and the operation command signal is inputted to the host-side control model unit. The corrected command signal is furthermore inputted to the drive-side control structure. This configuration produces an effective trajectory following capability in the control subject while minimizing the adjustment burden on a user.