Vehicle Turning Control Torque Adjustment
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Solution Overview
Problem
Existing vehicle turning control systems face challenges in generating appropriate yaw momentum due to limited traction or brake force capacity, leading to wheel slip and instability during turning maneuvers.
Innovation Solution
A turning control apparatus that calculates necessary and maximum yaw momentum values, adjusts driving torque between inside and outside wheels based on gripping capacity, and employs a torque adjustment limiting value to prevent wheel slip, using a system comprising a center differential, rear differential, and ECU with sensors and controllers to manage torque distribution and braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If driving torque is increased beyond the gripping capacity of the inside wheel to prevent over-steering, then the vehicle stability is improved, but the inside wheel slips and the degree of over-steering is increased
Solution Approach 1:
The patent dynamically adjusts the driving torque applied to each wheel based on real-time gripping capacity estimates. By changing the torque parameters within the gripping capacity limits rather than exceeding them, the system prevents wheel slip while maintaining vehicle stability during turning maneuvers.
Solution Approach 2:
The system continuously monitors wheel behavior and gripping capacity, using this feedback to adjust driving torque in real-time. This closed-loop control ensures that torque application remains within the gripping capacity of each wheel, preventing slip while achieving the desired turning control.
2Ease of operation
If driving torque difference between left and right wheels is varied to generate yaw momentum, then the turning control is improved, but the traction capacity is exceeded and wheel slip occurs
Solution Approach 1:
The patent calculates and adjusts driving torque parameters based on the estimated gripping capacity of each wheel. By varying torque within the available traction capacity rather than exceeding it, the system achieves improved turning control without causing wheel slip.
Solution Approach 2:
Instead of applying full torque difference needed for ideal turning control, the system applies a partial torque adjustment that remains within the gripping capacity limits. This prevents wheel slip while still achieving sufficient turning control through the available traction.
3Stability of the object's composition
If driving torque is adjusted to prevent over-steering, then the vehicle stability is improved, but the inside wheel gripping capacity is exceeded and wheel slip increases over-steering
Solution Approach 1:
The system dynamically adjusts the driving torque parameter applied to the inside wheel based on its estimated gripping capacity. By changing the torque to match the available capacity rather than exceeding it, the system maintains vehicle stability while preventing inside wheel slip that would worsen over-steering.
Solution Approach 2:
The system estimates the gripping capacity before applying driving torque and adjusts the torque accordingly to prevent wheel slip. This preliminary assessment and adjustment prevent the harmful effect of inside wheel slip before it can occur, maintaining stability during turning.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Improves vehicle turning ability and operatability by generating appropriate yaw momentum without exceeding wheel gripping capacities, thereby preventing wheel slip and enhancing stability during turns.
Implementation Method 1
the capacity of traction or brake force (i.e. adhesive friction between the wheel and the road surface) is limited
Data Source
AI summary
The turning control apparatus for a vehicle has a driving torque controlling mechanism adjusting driving torque of left and right wheels. The apparatus includes a maximum-yaw momentum value calculating means having means for estimating an outside-wheel gripping capacity, which is capacity of adhesive friction between the outside-wheel and a road surface, and an inside-wheel gripping capacity, which is capacity of adhesive friction between the inside-wheel and the road surface, and means for calculating a torque adjustment limiting value indicating an adjustment amount of driving torque by the driving torque controlling mechanism so that the adjustment amount does not exceed the gripping capacity. The maximum-yaw momentum value calculating means sets the maximum-yaw momentum value indicating possible yaw momentum, which is estimated if the driving torque is adjusted along with the torque-adjustment-limit value calculated by the torque adjustment limiting value calculating means.