Active Shock Absorber Control for Roll and Pitch Near Grip Limit
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Solution Overview
Problem
Existing methods for controlling active shock absorbers in road vehicles do not effectively maximize performance when driving near the grip limit, particularly in conditions of high acceleration and cornering, leading to suboptimal dynamic behavior and reduced driving comfort.
Innovation Solution
A method that utilizes an electronic control unit to adjust the active shock absorbers by determining desired changes in the vehicle's center of gravity, roll angle, and pitch angle based on real-time acceleration and steering data, using a combination of accelerometers, gyroscopes, and GPS to calculate and implement target forces for each shock absorber, thereby optimizing grip and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active shock absorbers are controlled using existing methods, then basic suspension function is maintained, but vehicle performance is not maximized when driving near the grip limit
Solution Approach 1:
The control unit calculates desired changes in center of gravity position, roll angle, and pitch angle in advance based on measured acceleration and steering angle, before the vehicle actually reaches the grip limit condition. This preliminary calculation allows the active shock absorbers to be pre-positioned for optimal performance.
Solution Approach 2:
The system continuously measures actual acceleration and steering angle, compares them with target values, and uses this feedback to dynamically adjust the desired attitude changes and shock absorber forces in real-time, maximizing performance as driving conditions change.
2Reliability
If active shock absorbers make autonomous movements to react to road stresses, then dynamic performance and driving comfort are improved, but control precision near grip limit is insufficient
Solution Approach 1:
The system replaces simple reactive mechanical suspension with an electronically controlled active suspension system that uses sensors (accelerometers, gyroscopes), control units, and electronic actuators to precisely control shock absorber movements based on calculated desired attitudes rather than just mechanical road forces.
Solution Approach 2:
The control unit dynamically changes multiple parameters including desired center of gravity position, roll angle, pitch angle, and individual shock absorber forces based on measured acceleration and steering angle, allowing precise adaptation to varying driving conditions near the grip limit.
3Reliability
If the vehicle attitude is adjusted to maximize performance, then tire grip and stability are improved, but load transfer is increased
Solution Approach 1:
The active shock absorbers generate counteracting forces to offset the load transfer caused by vehicle attitude adjustments. When the vehicle pitches or rolls to optimize tire grip, the active suspension applies opposing forces to reduce the unwanted load transfer, thereby maintaining grip while reducing harmful force distribution.
Data Source
AI summary
Method to control active shock absorbers of a road vehicle. Each active shock absorber is part of a suspension connecting a frame to a hub of a wheel and is provided with an actuator. The control method comprises the steps of: determining a longitudinal acceleration and a transverse acceleration of the road vehicle; establishing a desired roll angle based on the transverse acceleration; and establishing a desired pitch angle based on the longitudinal acceleration.