Steering Wheel Rotation Curbing with Backup Power-Off Locking
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Solution Overview
Problem
Existing steer-by-wire steering systems require continuous power supply for the steering lock device, leading to unnecessary power consumption when the vehicle is turned off, and there is a risk of the driver contacting the steering wheel during ignition off states.
Innovation Solution
A steering system with a separate power supply for the rotation curbing unit, using a backup power source to maintain operation during power-off periods, ensuring the steering wheel is locked and reducing power consumption by disconnecting the primary power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the steering lock device operates continuously after ignition off to curb steering wheel rotation, then the angle difference between steering wheel and turning wheels is reduced, but electric power from the first power supply is consumed unnecessarily
Solution Approach 1:
The power supply system is segmented into two independent power sources: the first power supply for normal vehicle operation and the second power supply (backup battery) specifically for the rotation curbing unit during power-off periods. This segmentation allows the steering lock function to operate independently without consuming the primary power supply, resolving the contradiction between reliability and energy consumption.
Solution Approach 2:
The second power supply acts as an intermediary power source that bridges the gap between ignition off state and next ignition on state. It provides the necessary electric power to the rotation curbing unit during this period, enabling the steering wheel to be secured without drawing power from the first power supply, thus eliminating unnecessary power consumption while maintaining safety functionality.
2Loss of energy
If the first power supply is disconnected during power-off state to save energy, then power consumption is reduced, but the steering lock device cannot operate to curb steering wheel rotation
Solution Approach 1:
The second power supply is pre-charged during normal vehicle operation (when the first power supply is active) to store sufficient electric energy. This preliminary energy accumulation ensures that when the first power supply is disconnected during power-off state, the rotation curbing unit can still operate reliably using the pre-stored energy, thus preventing both energy loss and maintaining steering wheel securing capability.
Solution Approach 2:
The second power supply serves as a cushioning power source that compensates for the disconnection of the first power supply during power-off periods. By having this backup power source ready in advance, the system ensures continuous operation of the rotation curbing unit without interruption, maintaining steering safety while preventing unnecessary energy consumption from the primary power supply.
Data Source
AI summary
A steering system is configured such that electric power is supplied to a steering actuator and a turning actuator from a first power supply when a power state of a vehicle is an on state and supply of the electric power from the first power supply is cut off when the power state is an off state. The steering system includes a rotation curbing unit configured to operate such that rotation of the steering wheel is curbed in at least a part of a first power-off period from when the power state becomes an off state until when the power state becomes the on state next, as an operating period, and a second power supply configured to supply, to the rotation curbing unit, the electric power required for operation of the rotation curbing unit in the operating period, the second power supply being different from the first power supply.