EPS Wheel Alignment Apparatus for Sensor Synchronization
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Solution Overview
Problem
Conventional wheel alignment methods for vehicles with electro-mechanical power steering (EPS) systems face challenges in synchronizing steering angle and torque sensors during alignment, leading to potential power steering assistance issues and the need for post-alignment sensor re-synchronization.
Innovation Solution
A method and apparatus that allows for adjusting the toe of front wheels without locking the steering wheel, using a level position determination based on the thrust angle, and re-adjusting the toe when the steering wheel moves beyond a predetermined angle, ensuring the EPS sensors remain unsynchronized during alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the steering wheel is locked at a level position during toe adjustment, then the alignment measurement precision is improved, but the EPS sensors become loaded and require post-alignment re-synchronization
Solution Approach 1:
The system performs preliminary leveling of the steering wheel using the EPS system before toe adjustment begins. This preliminary action establishes a known reference state for the EPS sensors, allowing subsequent toe adjustments to be made without locking the steering wheel, thereby avoiding the need for post-alignment re-synchronization while maintaining measurement precision
Solution Approach 2:
The system changes the operational parameters of the EPS system by disabling power assist during alignment operations. This parameter change allows the steering wheel to be adjusted without loading the EPS sensors, eliminating the need for re-synchronization while maintaining alignment precision through alternative measurement methods
2Stability of the object's composition
If the steering wheel is held in place using a steering wheel holder, then the alignment stability is improved, but the torque sensor cannot respond to rack movement creating a delta between sensors
Solution Approach 1:
The system performs preliminary leveling of the steering wheel using the EPS system before toe adjustment begins. This preliminary action establishes a known reference state for the EPS sensors, allowing subsequent toe adjustments to be made without locking the steering wheel, thereby avoiding the need for post-alignment re-synchronization while maintaining measurement precision
Solution Approach 2:
Instead of statically holding the steering wheel in place with a holder, the system dynamically levels the steering wheel using the EPS system and continuously monitors its position. This dynamic approach allows the steering wheel to move freely during adjustment while maintaining sensor synchronization through active control
3Ease of operation
If conventional alignment procedures are used with EPS systems, then the alignment process is simplified, but the EPS system interprets sensor delta as torque assist requests causing vehicle pull
Solution Approach 1:
The system performs preliminary leveling of the steering wheel using the EPS system before toe adjustment begins. This preliminary action establishes a known reference state for the EPS sensors, allowing subsequent toe adjustments to be made without locking the steering wheel, thereby avoiding the need for post-alignment re-synchronization while maintaining measurement precision
Solution Approach 2:
The system extracts or removes the steering wheel holder from the alignment process entirely. By eliminating this mechanical constraint, the system allows the EPS system to actively manage steering wheel position, preventing the creation of sensor deltas that would otherwise be interpreted as torque assist requests
Data Source
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AI summary
A method and apparatus are provided for aligning the wheels of a vehicle equipped with an electro-mechanical power steering system having a steering angle sensor, a torque sensor, and a torsion bar linking the steering angle sensor and the torque sensor. Embodiments include moving a steering wheel of the vehicle to a level position such that there is substantially no torque applied to the torsion bar; adjusting the toe of a first one of the front wheels of the vehicle after the steering wheel is moved to the level position; and moving the steering wheel substantially back to the level position, then re-adjusting the toe of the first one of the front wheels, when the steering wheel has moved more than a predetermined angle from the level position while adjusting the toe of the first one of the front wheels.