Left-Right Wheel Drive Force Distribution Control for Initial Turning Response
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Solution Overview
Problem
Conventional left-right wheel drive force distribution control systems exhibit poor initial turning response due to a small drive force difference between non-main drive wheels during the initial stage of a turn in small lateral acceleration regions, leading to slow rise in lateral acceleration and vehicle turning behaviors.
Innovation Solution
A vehicle left-right drive force distribution control apparatus with a controller that increases the target drive force difference between left and right wheels by a gain factor during the initial stage of a turn, ensuring a larger drive force difference as the vehicle starts turning, thereby enhancing the initial turning response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If only a smaller drive force difference is imposed between left and right non-main drive wheels when lateral acceleration is smaller, then high-speed stability is improved, but initial turning response deteriorates
Solution Approach 1:
The patent applies dynamics by making the drive force difference control adaptive to the vehicle's operating state. The controller dynamically adjusts the drive force difference between left and right non-main drive wheels based on detected lateral acceleration and steering angle, transitioning from a smaller drive force difference at low lateral acceleration to a larger drive force difference at high lateral acceleration, thereby resolving the contradiction between initial turning response and high-speed stability
Solution Approach 2:
The patent changes the control parameter (drive force difference) based on the operating condition (lateral acceleration). By detecting lateral acceleration and steering angle, the controller adjusts the drive force difference magnitude, implementing a parameter change strategy that improves initial turning response while maintaining high-speed stability through conditional control
2Force
If a larger drive force difference is imposed between left and right non-main drive wheels when lateral acceleration is larger, then cornering force is secured, but initial turning response remains poor
Solution Approach 1:
The patent applies preliminary action by detecting the steering angle and identifying when the vehicle enters the initial stage of turning. The controller proactively increases the drive force difference at the onset of turning (when lateral acceleration is still small) to improve initial turning response, before the vehicle reaches the high lateral acceleration phase where cornering force becomes the priority
3Speed
If the drive force difference is increased during initial stage of turn, then initial turning response is improved, but control complexity increases
Solution Approach 1:
The patent implements feedback control by continuously detecting lateral acceleration and steering angle, comparing these values against threshold criteria, and adjusting the drive force difference accordingly. The controller uses feedback from the vehicle's actual turning state to determine when to apply increased drive force difference, improving initial turning response through a systematic feedback mechanism rather than complex open-loop control
Data Source
AI summary
A rear wheel drive force difference setting gain is multiplied by a basic left-right rear wheel drive force difference steady-state control computation value for achieving a vehicle turning behavior steadily requested by a driver in order to calculate a final left-right rear wheel drive force difference steady-state control amount. The final left-right rear wheel drive force difference steady-state control amount is added to a left-right rear wheel drive force difference transient control amount to obtain left-right rear wheel rear wheel drive force difference. This difference is multiplied by feedback control coefficient to obtain a final rear wheel drive force difference. During an initial stage of turning in which a lateral acceleration is smaller than a turn initial stage determining value, the rear wheel drive force difference setting gain is set to A, which is larger than 1 and increases as the lateral acceleration decreases. As a result, the final rear wheel drive force difference is increased during the initial stage of turning and an initial turning response can be improved.