Steering Motor Current Limiting to Prevent Rack End Contact
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Solution Overview
Problem
Existing steering control apparatuses for vehicles do not adequately address the issue of excessive drive current supply to the steering motor during full steering, which can lead to contact between the rack end and the steering rack and increased wear on the steering motor.
Innovation Solution
A system that limits the steering motor drive current based on a set rotation angle, which is updated depending on the deviation between the calculated and set turning angles, to prevent excessive current supply and maintain optimal steering performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the steering motor is continuously operated in a steering direction during full steering, then the turning wheels can reach the steerable limit turning angle, but excessive drive current is supplied to the steering motor causing contact between the rack end and the steering rack
Solution Approach 1:
The patent changes the control parameter from unrestricted drive current supply to limited drive current supply based on rotation angle detection. When the steering motor rotation angle reaches the set rotation angle (corresponding to set turning angle smaller than steerable limit), the drive current is limited to prevent excessive current supply and rack end contact, while still allowing normal steering operation within safe parameters.
Solution Approach 2:
The patent implements feedback control by detecting the rotation angle of the steering motor and using this information to control the drive current supply. The rotation angle detecting unit continuously monitors the steering motor position, and the drive current is adjusted based on whether the detected angle exceeds the set rotation angle, creating a closed-loop control system that prevents harmful effects.
2Reliability
If the drive current is limited to prevent rack end contact, then the steering motor lifespan is extended, but the turning wheels cannot reach the steerable limit turning angle
Solution Approach 1:
The patent applies partial action by setting the limit on drive current supply only when the rotation angle exceeds the set rotation angle. Normal steering operations within the set angle range are not restricted and can reach the steerable limit turning angle when needed. The limitation is applied partially - only during the specific condition of exceeding the safe rotation angle threshold.
Solution Approach 2:
The patent implements dynamic control where the drive current limitation is not fixed but adapts based on the detected rotation angle. When the angle is within the safe range, full current supply is permitted for optimal steering performance. When the angle exceeds the set threshold, the current is dynamically limited to protect the motor, creating a flexible system that balances performance and reliability.
3Adaptability or versatility
If the set rotation angle is updated based on deviation between calculated and set turning angles, then the system adapts to actual steering conditions, but the control system complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-setting the rotation angle corresponding to the set turning angle before actual steering operations. This predetermined reference value is stored in advance and used for comparison during operation, eliminating the need for complex real-time calculations and simplifying the control logic while maintaining adaptability.
Solution Approach 2:
The patent replaces complex mechanical adjustment mechanisms with electronic detection and control. Instead of using mechanical devices to physically adjust steering angles or limit positions, the system uses rotation angle detecting units and electronic control of drive current, substituting mechanical complexity with simpler electronic sensing and control circuitry.
Data Source
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AI summary
A steering control apparatus of a vehicle includes a steering motor (2) configured to output a steering torque for steering turning wheel, a steering motor angle sensor (16) configured to detect a rotation angle of the steering motor (2), a steering motor drive current supply unit configured to supply the steering motor (2) with a steering motor drive current for setting a turning angle of the turning wheel to an angle corresponding to an operation of a steering wheel, a set rotation angle storage unit configured to store beforehand a set rotation angle which is the rotation angle of the steering motor (2) and which corresponds to the set turning angle that is set to an angle smaller than a limit turning angle to which the turning wheel is steerable, and a current supply quantity limiting unit configured to limit a supply quantity of the steering motor drive current not to make the rotation angle detected by the steering motor angle sensor (16) greater than the set rotation angle stored beforehand in the set rotation angle storage unit.