Vehicle Control System for Turning Radius Reduction
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Solution Overview
Problem
Existing vehicle control systems face challenges in reducing the turning circle in off-road conditions due to understeer and low surface friction, often resulting in increased noise, vibration, and harshness (NVH) and potential surface damage, as they either apply full brake force or transition abruptly between no and maximum braking.
Innovation Solution
A vehicle control system that applies negative torque to the inside trailing wheel when the steering angle exceeds a predetermined threshold, adjusting the torque based on driver demand and vehicle speed, and compensates with positive drive torque to maintain vehicle composure and reduce speed decrease, while limiting negative torque according to surface friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If full brake pressure is applied to the inside rear wheel to reduce turning circle, then the vehicle turning radius is reduced, but noise, vibration, and harshness increase and surface damage may occur
Solution Approach 1:
The brake control system dynamically adjusts brake pressure based on real-time monitoring of wheel slip conditions, steering angle, and vehicle speed. Instead of applying fixed full brake pressure, the system modulates brake force to maintain optimal turning assistance while preventing wheel lockup and reducing NVH and surface damage.
Solution Approach 2:
The system implements a feedback control mechanism where wheel speed sensors continuously monitor wheel rotation, and the controller adjusts brake pressure in response to detected wheel slip conditions. This closed-loop control ensures brake force is optimized to assist turning without exceeding surface friction limits that cause damage or excessive vibration.
2Speed
If full brake pressure is applied to reduce turning circle, then the vehicle responds more aggressively to steering input, but wheel lockup and loss of control may occur
Solution Approach 1:
The system dynamically modulates brake pressure based on real-time wheel slip detection and vehicle operating conditions. Brake force is adjusted continuously to maintain optimal slip conditions that provide aggressive turning response while preventing complete wheel lockup and loss of control.
Solution Approach 2:
The control system changes brake pressure parameters dynamically based on steering angle, vehicle speed, and wheel slip conditions. By adjusting brake force magnitude and duration according to real-time parameters, the system achieves aggressive response when needed while maintaining wheel rotation and control.
3Force
If maximum braking force is applied to the inside wheel, then turning assistance is maximized, but driver control and vehicle composure are degraded
Solution Approach 1:
The system applies partial brake force to the inside wheel rather than maximum braking, providing just enough turning assistance to reduce turning radius while maintaining driver control. The brake force is calibrated to be excessive enough to help turning but not so excessive as to compromise vehicle composure or driver intent.
Solution Approach 2:
The control system continuously monitors steering angle, vehicle speed, and wheel slip to adjust brake force magnitude. This feedback ensures brake assistance is proportional to turning needs and surface conditions, providing smooth driver-controlled turning without abrupt force application that would degrade vehicle composure.
4Reliability
If brake force is increased to prevent understeer on low friction surfaces, then turning performance improves, but energy loss and reduced vehicle speed increase
Solution Approach 1:
The system dynamically adjusts brake force application duration and magnitude based on vehicle speed and turning angle. Brake force is applied only when and where needed to prevent understeer, minimizing energy loss from braking while maintaining turning performance on low friction surfaces.
Solution Approach 2:
The control system applies brake force in periodic pulses or modulated cycles rather than continuous application, allowing the vehicle to maintain momentum between brake applications. This periodic braking provides turning assistance when needed while minimizing overall energy loss and speed reduction.
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
The system intuitively reduces the vehicle's turning radius, maintains composure during cornering, and reduces driver workload by minimizing speed decrease, all while preventing excessive wheel slip and surface damage.
Implementation Method 1
full brake pressure is applied to an inside rear wheel in order to induce turning of the vehicle
Implementation Method 2
the amount of negative torque being arranged to increase with increasing steering angle beyond the predetermined steering angle
Data Source
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AI summary
The present invention relates to a control system for a motor vehicle comprising means for receiving a signal indicative of a steering angle of a vehicle; and means for causing application of negative torque to one or more wheels of a vehicle to slow a wheel. The system is configured to perform a turn-assist operation in which the system causes application of negative torque to at least a first wheel of a vehicle being an inside trailing wheel when a steering angle exceeds a predetermined steering angle thereby to promote turning of a vehicle, the amount of negative torque being arranged to increase with increasing steering angle beyond the predetermined steering angle.