Robot Impedance Control for Contact-Evacuation Orientation Stability

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Solution Overview

Problem

Existing robot systems face issues with collision risks and excessive speed during evacuation when external forces are applied, leading to potential singular orientations or increased evacuation speeds, which can impede human work and safety.

Innovation Solution

A robot system equipped with servo motors, contact detection sensors, and impedance control units that adjust rigidity and viscosity parameters to manage external forces, allowing controlled orientation changes and preventing excessive movements by varying resistance to external forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the robot performs evacuation operation by moving in the direction where external force is decreased, then the robot can respond to human contact, but the robot may collide with obstacles or reach singular orientation

Engineering Contradiction:
Improverobot response to human contactVSAvoidcollision risk
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The robot dynamically adjusts its motion characteristics during evacuation based on real-time conditions. The control unit modifies movement speed, acceleration, and trajectory parameters to balance responsive evacuation with collision avoidance, transitioning from static safety protocols to adaptive dynamic control

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control unit continuously monitors external force magnitude, robot position, and environmental obstacles during evacuation. This feedback loop enables real-time adjustment of evacuation parameters, allowing the robot to respond appropriately to human contact while avoiding collisions with obstacles detected in the evacuation path

Inventive Principle:
Principle #23Feedback

2Reliability

If the robot is decelerated or stopped in response to human contact, then safety is improved, but the robot impedes human work by remaining in work areas

Engineering Contradiction:
ImprovesafetyVSAvoidhuman work efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The robot performs preliminary evacuation action immediately upon detecting human contact, proactively removing itself from the work area before it can impede human operations. This preliminary anti-action prevents the contradiction from manifesting by anticipating and avoiding the problematic state of remaining in the work area

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The robot dynamically transitions from a static stopped state to an active evacuation state, then to a controlled return state. This dynamic behavior allows the robot to prioritize safety during contact while subsequently restoring productivity by returning to work areas when safe to do so

Inventive Principle:
Principle #15Dynamics

3Reliability

If the robot evacuates continuously in response to excessive external force, then collision prevention is improved, but the robot may reach singular orientation or exceed maximum speed

Engineering Contradiction:
Improvecollision preventionVSAvoidrobot orientation stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The control unit implements periodic monitoring and adjustment of robot motion parameters during evacuation. By continuously evaluating external force magnitude and robot state at regular intervals, the system can modulate evacuation speed and direction changes to prevent singular orientations while maintaining collision prevention

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The robot employs dynamic motion control that adjusts acceleration, velocity, and trajectory based on real-time external force conditions. This dynamic approach allows smooth evacuation maneuvers that prevent singular orientations and exceed maximum speed only when necessary for collision avoidance

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system effectively prevents collisions and excessive speed by dynamically adjusting resistance to external forces, ensuring safe and efficient robot operations in human-work environments.

Implementation Method 1

contact detection sensors, and impedance control units that adjust rigidity and viscosity parameters to manage external forces

Methodology Applied
Scientific EffectForce detection: Force

Implementation Method 2

impedance control units that adjust rigidity and viscosity parameters to manage external forces

Methodology Applied
Scientific EffectRigidity adjustment: Elasticity

Implementation Method 3

impedance control units that adjust rigidity and viscosity parameters to manage external forces

Methodology Applied
Scientific EffectViscosity adjustment: Viscometer

Data Source

PatentEP4074473A1System, manufacturing method, controlling method, program, and recording medium
Publication Date: 2022.10.19 CANON KK
  • EP4074473A1 patent drawingFigure 1
  • EP4074473A1 patent drawingFigure 2
  • EP4074473A1 patent drawingFigure 3

AI summary

In a system including a robot (200) and a controller (300) controlling the robot (200), the controller (300) switches the robot (200) from a first state to a second state in which orientation change in accordance with external force applied to the robot (200) is more tolerated than the first state based on detection of contact of an object with the robot (200). The controller (300) switches the robot (200) from the second state to a third state in which the orientation change in accordance with the external force is more restricted than the second state after the orientation change in accordance with the external force applied to the robot (200) is started and while the external force is being applied to the robot (200).