Vehicle Motion Controller Roll Suppression via Understeering Inhibition
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Solution Overview
Problem
Existing vehicle motion control systems, such as those disclosed in JP-A-2001-219840, fail to effectively suppress roll angle and understeering in large-sized vehicles like trucks, as they often cause pitching phenomena and inadequate lateral sliding when attempting to control roll by increasing braking force on the turning-outside front wheel.
Innovation Solution
A vehicle motion control device that acquires vehicle speed, wheel speeds, lateral acceleration, and steering angle, and calculates steering angle lateral acceleration, determining if it's greater than a target value to set a rolling control mode, and inhibits the increase of wheel cylinder pressure if the calculated acceleration is less than the target, thereby preventing unnecessary understeering and roll angle increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If braking force is increased on the turning-outside front wheel to generate understeering for roll suppression, then rolling stability is improved, but pitching phenomenon occurs and lateral sliding does not occur properly in large-sized vehicles
Solution Approach 1:
The invention changes the control parameters by comparing steering angle lateral acceleration with target lateral acceleration to determine when understeering control should be active. This parameter-based control approach adjusts braking force application timing and magnitude to achieve roll suppression without causing pitching in large-sized vehicles.
Solution Approach 2:
The system uses feedback from lateral acceleration sensors and steering angle sensors to continuously monitor vehicle state and adjust understeering control accordingly. The control unit compares actual lateral acceleration with target values and modifies braking force on the turning-outside front wheel to maintain stability while avoiding harmful pitching effects.
Data Source
AI summary
If an actual lateral acceleration is equal to or greater than a target lateral acceleration Gth and at least one of a steering angle lateral acceleration Gys and a yaw-rate lateral acceleration Gyy is less than the target lateral acceleration Gth, the increase of the W/C pressure of the vehicle to be controlled is inhibited. Accordingly, it is possible to suppress the increase in the roll angle by actively generating the understeering to suppress rolling and to early suppress an increase in understeering if the increase in understeering is made to be unnecessary.