Motor Controller Brake Delay Detection via Timer Threshold
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Solution Overview
Problem
Conventional methods for detecting brake failures in motors are inadequate as they rely on comparing load torque measurements, which can be affected by variations in gravity load torque, leading to inaccurate determinations of brake states and potential operational delays.
Innovation Solution
A motor controller with a rotation control unit, brake control unit, rotation-state detection unit, timer, and determination unit that measures the time taken for the brake to transition from a released to a locked state, allowing for the detection of brake operation delay abnormalities by comparing this time against a predetermined threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If load torque measurement method is used to detect brake failure, then brake state can be detected, but detection accuracy deteriorates due to gravity load torque variations
Solution Approach 1:
The invention extracts the gravity load torque component from the total load torque measurement by separately measuring load torque at multiple rotation speeds and calculating the gravitational component. This extracted gravity component is then subtracted from subsequent measurements to eliminate its interfering effect on brake state detection accuracy.
Solution Approach 2:
The invention changes the operating parameter (rotation speed) to multiple distinct values and measures load torque at each speed. By varying the rotation speed parameter and analyzing the relationship between speed and load torque, the system can separate the gravity component from the brake friction component, thereby improving measurement precision for brake detection.
2Reliability
If brake operation time is not monitored, then system complexity is reduced, but brake operation delay abnormality cannot be detected
Solution Approach 1:
The control unit is configured to output a brake operation command before the brake actually operates, and the timer starts counting from this command output. This preliminary timing action allows the system to measure the actual response time of the brake mechanism, enabling detection of operation delays without adding complex sensor systems.
Solution Approach 2:
The timer provides feedback on the actual time taken for brake operation by comparing the elapsed time since command output with predetermined time thresholds. This time feedback mechanism enables the system to detect abnormal brake operation delays and trigger appropriate error handling, improving reliability with minimal added complexity.
Data Source
AI summary
Provided is a motor controller including: a rotation control unit configured to control a rotation of a motor; a brake control unit configured to control an operation of a brake for holding a rotor with respect to a stator of the motor; a rotation-state detection unit configured to detect a rotation state of the motor; a timer configured to measure, in a released state where an operation of the brake is released by the brake control unit, a time from an outputting of a command to change over a state of the brake to a locked state to a detection of a predetermined change in a rotation state of the motor by the rotation-state detection unit; and a determination unit configured to determine that a brake operation delay abnormality is present when the time, measured by the timer, is equal to or more than a predetermined threshold.