Open Loop Control for Electromechanical Brake Sensor Failure
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Solution Overview
Problem
Electromechanical brakes may malfunction or fail to activate correctly if sensors in a closed loop control system provide faulty or absent feedback, leading to incorrect or incomplete braking.
Innovation Solution
Implementing an open loop motor control system that uses an electronic controller to determine sensor failures and generate control signals for a permanent magnet synchronous machine to create a stator magnetic field, ensuring the rotor operates correctly and maintains braking functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If closed loop control is used with sensor feedback, then braking precision and control accuracy are improved, but system reliability deteriorates when sensors fail
Solution Approach 1:
The system performs preliminary sensor health checking before closed-loop control is fully engaged. The electronic controller monitors sensor signals for plausibility and prepares fallback to open-loop control in advance, ensuring seamless transition and maintaining reliability even when sensors fail during operation.
Solution Approach 2:
The system dynamically changes control parameters by switching between closed-loop and open-loop control modes based on sensor operational status. When sensors are functioning, high-precision closed-loop control is used; when sensors fail, the system transitions to open-loop control with adjusted parameters to maintain acceptable braking performance.
2Reliability
If open loop control is implemented as a failsafe mechanism, then system reliability improves during sensor failure, but braking precision deteriorates
Solution Approach 1:
The open-loop control provides partial braking functionality rather than full precision control when sensors fail. This partial action ensures the braking system remains operational and reliable, accepting reduced precision as a necessary compromise to maintain safety and functionality during sensor failure conditions.
3Reliability
If continuous sensor monitoring is added to detect failures, then reliability improves, but device complexity increases
Solution Approach 1:
The electronic controller performs self-diagnosis by monitoring sensor signal plausibility and operational status using its existing processing capabilities. This self-service approach enables the system to detect sensor failures without requiring separate dedicated monitoring hardware, thereby improving reliability while minimizing additional system complexity.
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
Ensures the electromechanical brake operates reliably even when closed loop control fails by providing a failsafe mechanism that maintains braking performance through open loop control, preventing asynchronous rotor behavior and ensuring sufficient torque for braking.
Implementation Method 1
activating the permanent magnet synchronous machine using the generated control signal to generate a stator magnetic field to operate the rotor of the permanent magnet synchronous machine
Data Source
AI summary
Systems and methods for providing open loop motor control for an electromechanical brake when closed loop motor control fails. The method includes determining, with an electronic controller, whether a rotor position sensor or a current sensor is not operating correctly, generating, with the electronic controller, a generated control signal for controlling a permanent magnet synchronous machine, and activating, with the electronic controller, the permanent magnet synchronous machine using the generated control signal to generate a stator magnetic field to operate the rotor of the permanent magnet synchronous machine of the electromechanical brake.