Master Arm Force Feedback for Realistic Remote Robot Operation

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Solution Overview

Problem

Existing remote control robot systems experience a gap in operational feel between the anticipated and actual forces received by the operator, particularly when handling heavy objects, leading to operational burden.

Innovation Solution

The system introduces an imaginary external force in the gravity direction independent of the slave arm's forces, compensated by a gravity compensating module, which adjusts the force magnitude through a setting value input, and applies it only when the operator grips the master arm, reducing the operational burden and aligning the felt and anticipated forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the gravity of the object held by the slave arm is completely canceled through the master arm, then the operational burden on the operator is reduced, but a gap arises between the anticipated feel and the received feel through the master arm

Engineering Contradiction:
Improveoperational burdenVSAvoidoperational feel gap
Core Design Contradiction:
Ease of operationVSLoss of information

Solution Approach 1:

The system applies an imaginary external force in the gravity direction that acts as a counterbalance to the canceled gravity, creating a simulated weight sensation. This imaginary force compensates for the complete gravity cancellation, providing the operator with an anticipated feel that matches the expected physical interaction, while the actual gravity cancellation continues to reduce operational burden.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The system independently adjusts the imaginary external force parameter separate from the actual gravity force. By changing this imaginary force parameter, the system can tune the operational feel to match operator expectations without affecting the actual gravity cancellation mechanism, thus resolving the contradiction between burden reduction and feel accuracy.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the master arm is driven based on force received by the slave arm minus the gravity force, then the operator senses only the reaction force, but the operational feel becomes unrealistic when handling heavy objects

Engineering Contradiction:
Improveforce feedback accuracyVSAvoidoperational realism
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The imaginary external force acts as an intermediary element between the actual reaction force and the operator's perception. It mediates the force feedback by adding a simulated gravity component that makes the operational feel realistic, while the underlying force calculation remains accurate by using the actual reaction force from the slave arm.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3626402B1Remote operation robot system
Publication Date: 2025.07.23 KAWASAKI JUKOGYO KK
  • EP3626402B1 patent drawingFigure 1
  • EP3626402B1 patent drawingFigure 2
  • EP3626402B1 patent drawing

AI summary

A remote control robot system includes a slave arm configured to perform a given work, a master arm having a motor configured to drive a joint, and configured to receive from an operator an operation to manipulate the slave arm, an instruction generating module configured to generate an instruction to apply to the master arm an imaginary external force in a given direction that is independent from a force received by the slave arm from the exterior, and a motor controller configured to supply, to the motor, drive current corresponding to the instruction sent from the instruction generating module.