Industrial Robot Arm Pose Adjustment by Single-Freedom Force Guidance

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Solution Overview

Problem

Current methods for manually guiding the pose of industrial robot manipulator arms are complex and difficult for operators to handle and program, lacking efficiency in translating manual forces into precise movements.

Innovation Solution

A method that detects the guiding force applied by an operator and determines the freedom of a reference coordinate system with the greatest force direction component, allowing force-controlled activation of the robot's drives to adjust the manipulator arm only in that selected freedom, with parameterized rigidity that reduces when the minimum force is exceeded, enabling smooth and controlled movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If force-controlled activation allows movement in multiple freedoms, then operator flexibility is improved, but control precision and safety deteriorate due to unintended movements

Engineering Contradiction:
Improveoperator flexibilityVSAvoidcontrol precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent segments the six-degree-of-freedom movement space into multiple selectable freedom directions. The controller allows the operator to select which specific freedom (e.g., linear X, linear Y, linear Z, rotational A, rotational B, rotational C) is active for manual guidance at any given time. This segmentation enables precise control by limiting movement to only the selected freedom while blocking others, thus maintaining both operator flexibility and control precision.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If rigidity is reduced for easy manual adjustment, then ease of operation is improved, but stability and safety deteriorate due to unintended collisions

Engineering Contradiction:
Improveease of manual adjustmentVSAvoidsafety
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent implements dynamic rigidity control where the robot manipulator's rigidity is adjusted in real-time based on operational requirements. During manually guided adjustment, the system reduces rigidity in the selected freedom to allow easy operator manipulation, while maintaining high rigidity in non-selected freedoms to prevent unintended movements and collisions. This dynamic adaptation resolves the contradiction between ease of operation and safety.

Inventive Principle:
Principle #15Dynamics

3Extent of automation

If force control is applied in all directions, then comprehensive control is improved, but system complexity increases making it difficult to program

Engineering Contradiction:
Improvecomprehensive controlVSAvoidprogramming complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The patent applies partial action by activating force control only in the specifically selected freedom direction rather than in all six degrees of freedom simultaneously. The controller receives operator input and applies force control exclusively to the chosen freedom (e.g., only linear X movement), while other freedoms remain blocked or controlled through simpler mechanisms. This partial activation significantly reduces programming complexity while maintaining comprehensive control capability when needed.

Inventive Principle:
Principle #16Partial or excessive action

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

Simplifies the handling and programming of industrial robots by allowing precise, force-controlled adjustments of the manipulator arm's pose, enhancing operator control and safety by limiting movement to the selected freedom, reducing the risk of unintended collisions.

Implementation Method 1

force-controlled activation of the drives of the industrial robot in such a way that an adjustment of a predetermined, with reference point connected to the manipulator arm by moving the manipulator arm during a manually guided adjustment of the pose of the manipulator arm only in the selected freedom

Methodology Applied
Scientific EffectForce control: Force

Implementation Method 2

one before reaching the predetermined one Minimum force parameterized rigidity is maintained during the application of the guide force and the rigidity is only reduced when the guide force is reduced again after the specified minimum force has been reached and/or exceeded

Methodology Applied
Scientific EffectRigidity control: Elasticity

Data Source

PatentEP2851162B1Method for manually handled adjustment of the pose of an industrial robot manipulator arm of an industrial robot and associated industrial robot
Publication Date: 2021.03.31 KUKA DEUT GMBH
  • EP2851162B1 patent drawingFigure 1
  • EP2851162B1 patent drawingFigure 2
  • EP2851162B1 patent drawingFigure 3

AI summary

The invention relates to a method for manually adjusting the pose of a manipulator arm (2) of an industrial robot (1), comprising the steps: - detecting (S4) a guiding force applied to the manipulator arm (2) by an operator of the industrial robot (1), - determining (S5) the freedom of a reference coordinate system (R, RW, RB, RZ, RP) in whose direction the guiding force has its largest force direction component, as a selected freedom, - force-controlled actuation (S6) of the drives of the industrial robot (1) such that an adjustment of a predetermined reference point (P) connected to the manipulator arm by moving the manipulator arm (2) during a manually guided adjustment of the pose of the manipulator arm (2) only takes place in the selected freedom.