Robot Joint Resonance Testing on Normal Motion Trajectories
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Solution Overview
Problem
Existing methods for detecting transmission failures in robot arms, such as tooth skipping in reduction gears, often require stopping non-target joints, altering the robot's motion, or driving at varying speeds to find resonance, leading to inefficiencies and potential collisions with peripheral equipment.
Innovation Solution
An examination method that generates motion data causing the target joint to resonate while maintaining the original trajectory, using an output shaft encoder to detect resonance amplitude and compare it with reference values, allowing safe and efficient detection of transmission failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If joints other than the examination target are stopped to detect transmission failure, then measurement precision is improved, but productivity deteriorates and collision risk increases
Solution Approach 1:
The patent applies dynamics by maintaining the robot arm in motion during examination rather than stopping it. The control unit continues to output trajectory data that causes the robot arm to move along its normal production trajectory, allowing transmission failure detection without interrupting the examination target joint's motion. This dynamic approach resolves the contradiction by enabling accurate measurement while maintaining productivity.
Solution Approach 2:
The patent makes the examination method universally applicable to the robot's normal production trajectory. By using the existing production trajectory data and continuing normal motion control, the examination process becomes multi-functional - it both produces work and detects transmission failures simultaneously. This eliminates the need to stop other joints or alter the trajectory, resolving the contradiction between measurement precision and productivity.
2Object-affected harmful factors
If the robot trajectory is altered to avoid peripheral equipment during examination, then collision risk is reduced, but productivity deteriorates and examination complexity increases
Solution Approach 1:
The patent applies self-service by using the robot's own normal production trajectory for the examination process. The control unit utilizes the existing trajectory data that the robot already follows during production, eliminating the need to create separate examination trajectories or alter the robot's path. This self-service approach resolves the contradiction by maintaining simplicity while avoiding collisions through proper trajectory selection.
Solution Approach 2:
The patent applies preliminary action by pre-selecting an appropriate production trajectory that avoids peripheral equipment before the examination begins. The control unit chooses trajectory data that naturally keeps the robot arm away from obstacles, so no additional collision avoidance maneuvers are needed during the examination. This preliminary selection resolves the contradiction by simplifying the examination procedure while maintaining safety.
3Measurement precision
If joints are stopped for transmission examination, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The patent applies continuity of useful action by maintaining the robot arm's motion throughout the examination process. The control unit continues to output trajectory data that drives the robot arm along its production trajectory, ensuring continuous useful action rather than interrupting motion. This resolves the contradiction by enabling accurate transmission state detection without time loss from stopping and subsequent restoration.
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
Enables safe and efficient detection of transmission failures by resonating the joint on its normal production path, reducing the risk of collisions and shortening examination time, while maintaining the robot's operational safety and accuracy.
Implementation Method 1
generating examination motion data for driving a joint as an examination target under a driving speed that causes the examination target joint to resonate
Data Source
AI summary
A method for examining a robot apparatus which includes a driving source configured to drive a joint, the position and orientation of which are controlled based on trajectory data determined in advance for a normal motion. The examination method includes generating examination motion data for driving a joint as an examination target under a driving speed that causes the examination target joint to resonate and causing the examination target joint to pass through a path based on the trajectory data. A resonance amplitude of the joint is acquired based on the examination motion data.