Redundant Robot Teach Programming With Optimized Joint Resolution

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Solution Overview

Problem

Programming redundant industrial robots is complex and prone to errors due to unresolved redundancy, leading to unpredictable robot behavior and potential collisions during automatic execution of programmed motion sequences.

Innovation Solution

A method that involves manually adjusting the pose of a manipulator arm with redundant joints by recalculating joint position values to eliminate redundancy, allowing automatic adjustment of all joints based on optimized values, providing force feedback for manual adjustment of redundant joints to optimize static and kinetic properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If redundancy resolution is performed using mathematical algorithms during programming, then the robot can handle complex tasks with multiple degrees of freedom, but the programming process becomes complex and error-prone

Engineering Contradiction:
Improverobot's ability to handle complex tasksVSAvoidprogramming process complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The robot controller automatically resolves redundancy and calculates optimized joint positions without requiring complex mathematical algorithms from the programmer. The system serves itself by autonomously determining the optimal configuration based on predefined criteria, simplifying the programming process while maintaining adaptability

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system changes the parameter representation from complex mathematical redundancy resolution to simple teach position coordinates. By transforming the problem from joint space to task space, the programming becomes straightforward while the controller handles the complex calculations automatically

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the manipulator arm is manually adjusted to achieve desired pose, then programming becomes more intuitive, but the robot behavior during automatic execution becomes unpredictable due to unresolved redundancy

Engineering Contradiction:
Improveprogramming intuitivenessVSAvoidrobot behavior predictability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system performs preliminary resolution of redundancy by calculating optimized joint positions before automatic execution. During the teach phase, the controller pre-computes the joint configuration that will be used during execution, ensuring consistent and predictable behavior while maintaining manual adjustability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system provides feedback by displaying the calculated joint positions to the operator during manual adjustment. This allows the programmer to see the relationship between teach positions and joint configurations, ensuring predictability while maintaining intuitive programming

Inventive Principle:
Principle #23Feedback

3Device complexity

If redundant joints are fixed to eliminate redundancy, then the robot controller becomes simpler, but the robot loses adaptability for optimizing static and kinetic properties

Engineering Contradiction:
Improvecontroller complexityVSAvoidoptimization capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The system dynamically resolves redundancy based on the current task and configuration rather than fixing joint positions. The controller adaptively calculates optimized joint positions for each teach point, allowing the robot to optimize static and kinetic properties for different tasks while maintaining a relatively simple controller architecture

Inventive Principle:
Principle #15Dynamics

4Adaptability or versatility

If force feedback is provided for manual adjustment of redundant joints, then the operator can optimize kinetostatic properties, but the system complexity increases

Engineering Contradiction:
Improvekinetostatic optimizationVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system introduces force feedback as an intermediary between the operator and the redundant joints. This allows the operator to feel the effects of different joint configurations and make informed decisions about optimization, while the controller handles the complex calculations automatically, managing system complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2868445B1Method for programming sequences of movements of a redundant industrial robot and associated industrial robot
Publication Date: 2022.10.05 KUKA DEUT GMBH
  • EP2868445B1 patent drawingFigure 1
  • EP2868445B1 patent drawingFigure 2
  • EP2868445B1 patent drawingFigure 3

AI summary

The invention relates to a method for programming movement sequences of a redundant industrial robot (1) by manually adjusting the pose of a manipulator arm (1a) of the industrial robot (1), which has several successive links (5-12) connected by adjustable joints (4) comprising at least one redundant joint (4) which are adjustable and controlled by at least one robot controller (2) of the industrial robot (1), comprising the steps: - manually adjusting the link (5-12) of the manipulator arm (1a) to which a tool reference point (16) is assigned, from a first position and first orientation in space to a second position and/or second orientation in space,- Calculating the joint position values ​​of all joints (4) of the manipulator arm (1a) from the second position and second orientation of the tool reference point (16) of the manipulator arm (1a) by resolving the redundancy through the determination of an optimized joint position value of the at least one redundant joint (4), - automatically adjusting all joints (4) of the manipulator arm (1a) controlled by the robot controller (2) based on the calculated, optimized joint position values ​​during manually guided adjustment.