Steer-By-Wire Power Switching During Main Supply Voltage Drop
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Solution Overview
Problem
Existing vehicle power supply systems with steer-by-wire steering devices face issues where the output-limited state during backup power supply is inadvertently canceled before the primary power source fully recovers, leading to potential operational failures.
Innovation Solution
A vehicle power supply system with a secondary power source and a control method that includes a power source control unit and steering control unit to manage the transition between primary and secondary power sources, ensuring the output-limited state is maintained until the primary power source fully recovers, using state detection and switching processes to manage power supply states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the output-limited state is canceled as soon as the first power source recovers from abnormality, then the steering system can return to normal operation quickly, but the output-limited state may be canceled prematurely before the power source fully recovers, leading to operational failures
Solution Approach 1:
The system performs preliminary verification of the first power source's recovery status before canceling the output-limited state. The power source control unit checks whether the first power source has fully recovered from abnormality before transitioning from the second state back to the first state, ensuring that the output-limited state is only canceled when recovery is complete and verified.
Solution Approach 2:
The power source control unit continuously monitors the state of the first power source and uses this feedback information to determine when to cancel the output-limited state. The state detection process detects the recovery of the first power source, and this detected information feeds back to the steering control unit to appropriately timing the cancellation of the output-limited state.
2Reliability
If the system uses a backup power source to maintain steering operation during primary power failure, then steering availability is improved, but the system complexity increases due to additional power source management requirements
Solution Approach 1:
The power source control unit acts as an intermediary between the first power source and the steering control unit. It manages the switching between power sources and the transition of operational states, simplifying the overall system architecture by centralizing power management functions in a dedicated control unit rather than distributing complexity across multiple components.
Data Source
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AI summary
A vehicle power supply system includes a power source control device (88) that executes a process of switching a connection state of a driving circuit (61a) to the main power source (45) and an auxiliary power source (81) including; a process of switching the connection state so as to transition to a backup state as a voltage decrease of the main power source (45) occurs, and a process of switching the connection state so as to transition to a normal state as the voltage decrease of the main power source (45) is resolved. After a voltage decrease of the main power source (45) occurs, a turning-side control device (60) of a steering control unit (1) sets an output-limited state for a turning-side motor (32). The output-limited state is canceled upon the power source control device (88) completing switching of the connection state so as to transition.