Robot Electromagnetic Brake Malfunction Detection
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Solution Overview
Problem
Existing malfunction detection methods for electromagnetic brakes in industrial robots are inadequate, as they often result in after-the-fact control, leading to unreliable prevention of arm drooping due to gravitational forces, and cannot reliably suppress inadvertent robot motions during detection.
Innovation Solution
A dual-relay system with a main relay and sub-relays, where the main relay is controlled to close for a specific period to detect sub-relay functionality, and both are managed to prevent unintended robot activation when malfunctions are detected, ensuring timely locking of the brakes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If malfunction detection is performed after robot activation, then the detection process is simple, but the brake locking action occurs too late to prevent arm drooping
Solution Approach 1:
The patent performs malfunction detection before robot activation by checking relay contact states in advance. The controller detects whether relay contacts are abnormally closed before the robot starts operating, and only activates the robot if no abnormalities are found. This preliminary detection ensures that if a relay malfunction occurs, it is detected before it can cause arm drooping, eliminating the time delay associated with post-activation detection.
2Reliability
If relay contacts are continuously monitored during operation, then malfunction detection reliability is improved, but robot motion suppression during detection becomes difficult
Solution Approach 1:
The patent performs malfunction detection periodically at specific moments - specifically before robot activation and after each work routine completion. During these detection periods, the robot is stopped and brake locks are activated to prevent inadvertent motion. By concentrating detection activities at these discrete periodic intervals rather than continuously monitoring during operation, the system achieves high detection reliability while ensuring robot motion suppression during detection phases.
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
This approach allows for reliable detection and prevention of arm drooping by ensuring the electromagnetic brakes are locked in a timely manner, effectively suppressing inadvertent robot motions during malfunction detection.
Implementation Method 1
an electromagnetic brake braking a motor with an excitation coil
Implementation Method 2
relays switching over between the current supply state (energized) and the current no-supply state (non-energized) of the brake
Data Source
AI summary
An apparatus is provided for detecting a malfunction occurring in an electromagnetic brake of a robot. In the apparatus, the main relay and the sub-relay are controlled to open the main contact and the sub-contact when the robot is activated. Detecting is then made whether or not the main contact is malfunctioning, by monitoring an energized state of the main contact. Activation of the robot is stopped when the main contact is malfunctioning and the main relay is controlled to close the main contact for a given period of time when that the main contact is operating normally. Detecting is further made as to whether or not the sub-contact is malfunctioning, by monitoring an energized state of the sub-contact The activation of the robot is stopped when the sub-contact is malfunctioning and the main relay is controlled to close the main contact when the sub-contact is operating normally.