Robot Hand Admittance Control for Low-Force Direct Teaching

Solution Overview

Problem

Existing robots require operators to apply significant force during direct teaching, making it difficult to achieve precise motion control due to inertia and force requirements.

Innovation Solution

A robot equipped with a force sensor and a control device that performs admittance control, allowing the robot hand to move based on detected forces, thereby reducing the required force for precise motion teaching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If impedance control is used for direct teaching, then the robot arm can be controlled with force feedback, but the operator is required to apply relatively greater force and it becomes difficult to move the robot arm satisfactorily due to inertia

Engineering Contradiction:

Improveease of direct teaching operationVSAvoidforce required by operator

Core Design Contradiction:

Ease of operationVSForce

Solution Approach 1:

The patent inverts the control approach by switching from impedance control (motion input, force output) to admittance control (force input, motion output). This inversion allows the operator's applied force to directly determine the robot hand's position, eliminating the need to overcome robot arm inertia and reducing the force required for operation.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the control parameter relationship by using admittance control where the robot hand position is determined based on the force detected by the force sensor. This parameter change from motion-based control to force-based control enables precise motion teaching with reduced operator force.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If impedance control is used for direct teaching, then force feedback is provided to the operator, but it becomes difficult to achieve precise motion teaching due to the influence of robot arm inertia

Engineering Contradiction:

Improveprecision of motion teachingVSAvoidease of moving robot arm

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent inverts the control approach by switching from impedance control (motion input, force output) to admittance control (force input, motion output). This inversion allows the operator's applied force to directly determine the robot hand's position, eliminating the need to overcome robot arm inertia and reducing the force required for operation.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent uses force sensor feedback to detect the operator's applied force and determines the robot hand position based on this force input. This feedback mechanism enables precise motion teaching by directly translating operator intent into robot motion without the interference of system inertia.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12318925B2Robot and method of controlling the same

Publication Date: 2025.06.03 SINTOKOGIO LTD

AI summary

A robot includes a robot hand, a robot arm, a force sensor, and a control device. The control device performs admittance control to determine a position of the robot hand in accordance with a force detected by the force sensor, and provides, to the robot arm, an instruction to move the robot hand to the determined position. Further, the control device records, as teaching data, the instruction provided to the robot arm.