Vehicle Pitch Control During Stop Using Reverse Torque
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Solution Overview
Problem
End-of-stop suspension rebound, also known as head bob or head nod, causes discomfort in passengers and cargo due to sudden release of forward momentum and insufficient damping in vehicle suspensions during braking and stopping.
Innovation Solution
A vehicle control system with a pitch component and rebound component that determines forward pitch during braking, applies brake pressure to non-driven wheels, and applies reverse torque to driven wheels to limit suspension rebound, using feedback control and continuously controlled damping to maintain a downward force on the front suspension and cancel out rebound.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional braking is used to stop the vehicle, then braking distance is achieved, but suspension rebound causes passenger discomfort and cargo safety issues
Solution Approach 1:
The system applies preliminary anti-action by detecting forward pitch during braking and applying reverse torque to driven wheels before the suspension rebound can cause discomfort. The pitch control component monitors vehicle pitch and applies counteracting torque to prevent the harmful rebound effect, thereby improving passenger comfort while maintaining cargo safety through controlled suspension movement.
Solution Approach 2:
The system implements feedback control by continuously monitoring vehicle pitch angle and suspension movement, then adjusting the reverse torque applied to driven wheels accordingly. The pitch control component uses real-time pitch data to modulate brake pressure and torque application, creating a closed-loop control system that maintains optimal suspension damping throughout the braking process, thereby preventing both passenger discomfort and cargo displacement.
2Object-affected harmful factors
If brake pressure is applied to limit suspension rebound, then passenger comfort is improved, but braking distance may be affected
Solution Approach 1:
The system applies local quality by differentiating between driven and non-driven wheels in the braking process. Brake pressure is selectively applied to non-driven wheels while reverse torque is applied to driven wheels, creating localized control over different parts of the suspension system. This selective braking approach limits suspension rebound in the front suspension while maintaining effective braking performance through coordinated action on all wheels.
Solution Approach 2:
The system implements dynamics by continuously adjusting brake pressure and torque levels based on real-time vehicle pitch and suspension state. The pitch control component dynamically modulates the reverse torque applied to driven wheels and brake pressure on non-driven wheels throughout the braking process, adapting the control forces to match the evolving suspension rebound conditions, thereby maintaining both comfort and braking efficiency.
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
Reduces end-of-stop rebound rate without sacrificing braking distance, improving passenger comfort and cargo safety by maintaining a smooth ride, and can be implemented in existing vehicles through software updates, ensuring safety and satisfaction.
Implementation Method 1
A brake is applied to a wheel of the vehicle to reduce a suspension rebound rate
Data Source
AI summary
A system for vehicle pitch control during braking includes a pitch component and a rebound component. The pitch component is configured to determine that a vehicle has a forward pitch during braking. The rebound component is configured to, in response to the vehicle achieving a substantially zero forward velocity, apply brake pressure to one or more non-driven wheels using one or more brakes and apply reverse torque to one or more driven wheels using a motor or engine.