Electromechanical Steering Emergency Disconnection Circuit
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Solution Overview
Problem
Existing electromechanical steering systems face challenges in reliably disconnecting the electric motor from the system in the event of a sudden failure of the main control unit, which can lead to the electric motor generating steering resistance torques, potentially blocking the vehicle's steering.
Innovation Solution
The proposed electromechanical steering system includes a circuit arrangement with a safety unit designed to disconnect the electric motor from the voltage supply unit. In the event of a main control unit failure, an auxiliary control unit, powered by an energy storage unit, actuates the safety unit to disconnect the electric motor, preventing resistance torques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the main control unit fails suddenly, then the electric motor may generate steering resistance torques that block steering, but adding complex protection circuits may increase device complexity
Solution Approach 1:
The control system is segmented into a main control unit and a separate auxiliary control unit. The auxiliary control unit is specifically responsible for monitoring main control unit status and executing emergency disconnection, separating the safety function from the main control functions. This segmentation allows the system to maintain simplicity while improving reliability through functional separation.
Solution Approach 2:
The auxiliary control unit acts as an intermediary between the main control unit and the disconnection mechanism. It monitors the main control unit's health status and intermediates the disconnection process by activating the disconnection mechanism when failures are detected, preventing direct harmful effects while maintaining system simplicity.
2Object-generated harmful factors
If the electric motor is electrically disconnected to prevent generator effect torques, then steering resistance is eliminated, but the disconnection mechanism itself adds device complexity
Solution Approach 1:
The harmful generator effect is eliminated by extracting the electric motor from the electrical circuit through the disconnection mechanism. This separates the motor from the voltage supply unit, preventing it from generating resistance torques while maintaining the simplicity of the overall system architecture.
Solution Approach 2:
The disconnection mechanism is prepared in advance and can be activated immediately upon detection of main control unit failure. The auxiliary control unit continuously monitors system status and can trigger the pre-positioned disconnection mechanism, eliminating harmful torques before they can affect steering operations.
3Reliability
If an auxiliary control unit with energy storage is added to ensure safe disconnection during main control unit failure, then steering safety is improved, but the system complexity increases
Solution Approach 1:
The auxiliary control unit is designed with multi-functionality, serving both as a monitor of the main control unit's health and as the executor of emergency disconnection. The energy storage unit serves dual purposes: powering the auxiliary control unit during normal operation and providing emergency power for disconnection when the main control unit fails. This multi-functionality reduces overall system complexity despite adding components.
Solution Approach 2:
The auxiliary control unit with energy storage is designed to autonomously detect main control unit failures and execute disconnection without external intervention. The energy storage unit automatically provides power when needed, and the auxiliary control unit self-manages the monitoring and execution functions, reducing the need for additional complex control logic.
Data Source
AI summary
An electromechanical steering system comprises a steering shaft, via which a steering command can be specified by a steering handle, and a steering actuator having an electric motor and having a circuit arrangement assigned to the electric motor, wherein the steering actuator is designed to use the electric motor to convert a specified steering command into a steering movement of steerable wheels of the motor vehicle, wherein the circuit arrangement comprises a connection unit for connecting to a voltage source of a motor vehicle as the main energy source, a voltage supply unit for providing voltages required for operation, a main control unit, a safety unit designed to disconnect the electric motor from the voltage supply unit, an energy storage unit and an auxiliary control unit, wherein the auxiliary control unit is designed to actuate the safety unit for disconnecting the electric motor from the voltage supply unit in the event of a malfunction of the main control unit by energy provided by the energy storage unit.