Vehicle Attitude Controller Pitch-Roll Coupling Control
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Solution Overview
Problem
Existing vehicle attitude controllers focus primarily on reducing roll rate, leading to poor transient turning feel and ride quality, especially when tires are in a non-linear region, resulting in reduced cornering power and increased roll steer, which degrades stability and ride quality.
Innovation Solution
A vehicle attitude controller that dynamically adjusts damping forces to improve roll feeling by controlling pitch rate in accordance with roll rate, using sensors and actuators to generate pitch moments and suppress roll, while switching control rates based on vehicle motion to maintain stability in critical regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If control is continued in the non-linear region to improve roll feeling, then pitch-roll coupling is enhanced, but critical performance is lowered due to increased transient roll angle and reduced cornering power
Solution Approach 1:
The controller dynamically switches between two control modes based on tire operating conditions: in the linear region, pitch rate is controlled in accordance with roll rate to improve roll feeling; in the non-linear region, the control mode switches to prioritize stability by limiting transient roll angle. This dynamic adaptation resolves the contradiction by adjusting control strategy according to real-time vehicle conditions.
Solution Approach 2:
The controller changes the control parameters (control rate between pitch control and roll suppression) based on the determined vehicle motion region. When tires are in the linear region, higher control rate is applied for pitch-roll coupling; when in the non-linear region, control rate is adjusted to prioritize stability, thereby resolving the contradiction between roll feeling and critical performance.
2Stability of the object's composition
If damping-force characteristic is switched to hard side to improve steering stability, then steering stability is improved, but load fluctuation is increased which degrades ride quality
Solution Approach 1:
The controller applies different damping-force characteristics to different wheels based on local conditions. When tires are in the non-linear region, the controller selectively adjusts damping forces to suppress roll while maintaining ride quality, rather than uniformly switching all dampers to hard characteristic. This localized control resolves the contradiction between steering stability and ride quality.
Solution Approach 2:
The damping-force characteristic is dynamically adjusted based on the determined vehicle motion region and real-time vehicle state. The controller switches between soft and hard damping characteristics according to whether tires are in linear or non-linear regions, resolving the contradiction by adapting the damping property to current operating conditions rather than using a fixed hard characteristic.
3Ease of operation
If pitch rate is controlled in accordance with roll rate to improve roll feeling, then transient turning feel is improved, but control complexity increases
Solution Approach 1:
The control system is segmented into distinct functional modules: a determining unit that identifies vehicle motion region, a first control unit that implements pitch-roll coupling control, and a second control unit that implements stability-oriented control. This segmentation resolves the contradiction by organizing complex control logic into manageable, modular components with clear division of responsibilities.
Solution Approach 2:
The controller uses feedback from sensors to determine vehicle motion region and tire operating conditions, then adjusts control strategy accordingly. The feedback mechanism enables the system to automatically select appropriate control mode (pitch-roll coupling or stability priority) based on real-time conditions, resolving the contradiction without requiring complex manual intervention or overly complicated control algorithms.
Data Source
AI summary
A vehicle attitude controller capable of improving turning operability, steering stability, and ride quality of a vehicle. In a normal-operation region, a pitch control unit for calculating a target pitch rate in accordance with a roll rate performs control in priority to a roll suppression section. In this case, a target damping force calculated in the pitch control unit is weighed to control a damping-force characteristic of the dampers so that a pitch rate becomes equal to the target pitch rate. In a critical region in which a road-surface gripping state of the vehicle tires is bad, the roll suppression section performs control in priority to the pitch control unit so as to weigh a target damping force calculated in the roll suppression section. As a result, the damping-force characteristic of the dampers is controlled so as to increase the amount of roll suppression control.