Five-Six Axis Mixing Control for Industrial Robot Rigidity

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Solution Overview

Problem

Industrial robots with serial mechanisms and six degrees of freedom suffer from reduced rigidity, leading to low machining precision under cutting forces and gravity, limiting their application in material processing.

Innovation Solution

A five-axis and six-axis mixing control method for industrial robots, where each joint shaft is connected by rods to form both five-axis and six-axis robots, with independent motion control channels to optimize joint movement and improve rigidity, utilizing D-H parameter lists and transformation matrices for kinematic solutions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a six-axis serial robot structure is adopted to increase degrees of freedom, then the robot's flexibility and work space are improved, but the rigidity of the end effector is reduced leading to low machining precision

Engineering Contradiction:
Improverobot flexibilityVSAvoidmachining precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent segments the robot control into two independent channels: a five-axis rigid channel for high-precision machining operations and a six-axis flexible channel for workpiece transport. This segmentation allows each channel to be optimized for its specific function, resolving the contradiction between flexibility and precision

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The robot system is designed with multi-functionality by enabling the same physical robot to operate in two distinct modes through channel switching: precision machining mode (five-axis) and flexible transport mode (six-axis), making the system adaptable to different operational requirements

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If the number of joint shafts is increased to six degrees of freedom, then the robot can perform more complex operations, but the rigidity is weakened due to the serial mechanism structure

Engineering Contradiction:
Improveoperation complexityVSAvoidrobot rigidity
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The system dynamically switches between five-axis and six-axis control modes based on operational requirements. The control system can activate only the necessary axes for each task, maintaining rigidity when fewer axes are needed while providing flexibility when all six axes are utilized

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If a serial mechanism with six joint shafts is used, then the robot achieves six degrees of freedom for versatile operations, but the end effector rigidity becomes the worst due to cumulative flexibility

Engineering Contradiction:
Improvedegrees of freedomVSAvoidend effector stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The control is segmented into two independent channels that can be selectively activated. The five-axis channel provides stable, rigid control for machining while the six-axis channel provides flexible positioning, allowing the system to maintain stability when high precision is required

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3175958B15-axis and 6-axis mixing control method for industrial robot and system thereof
Publication Date: 2019.06.26 KEDE NUMERICAL CONTROL CO LTD
  • EP3175958B1 patent drawingFigure 1
  • EP3175958B1 patent drawingFigure 2
  • EP3175958B1 patent drawingFigure 3

AI summary

A five-axis and six-axis mixing control method for industrial robot and a system thereof are disclosed. The mixing control method includes the following steps: installing an end effector on each end of the fifth joint shaft and the sixth joint shaft; the rods connected in series by the first, the second, the third, the fourth and the fifth joint shaft form a five-axis robot, and the rods connected in series by the first, the second, the third, the fourth, the fifth and the sixth joint shaft form a six-axis robot. Configuring the five-axis robot corresponding to the first channel, and the six-axis robot corresponding to the second channel; obtaining respectively the motion target position of each joint shaft of the five-axis and six-axis robot. According to the obtained motion target position of each joint shaft of the five-axis and six-axis robot, the first channel implemented to control the movement of each joint shaft of the five-axis robot, and the second channel is implemented to control the movement of each joint shaft of the six-axis robot. Therefore, the five-axis robot can be used to process the material, with reducing the flexibility of mechanical connection, reducing the vibration in the material processing process, performing workpiece transport by means of the 6-axis robot, and maintaining the flexibility of operation