Vehicular Motion Control via Longitudinal Acceleration Adjustment
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Solution Overview
Problem
Existing vehicular motion control systems face challenges in maintaining traveling stability and reducing driver discomfort during turns, especially when the vehicle's lateral slip angle is large, as they require specialized systems like steer-by-wire and struggle to generate the expected yaw moment effectively.
Innovation Solution
A vehicular motion control device that includes a target trajectory acquisition unit and a speed control unit capable of adjusting longitudinal acceleration to follow a target trajectory by increasing or decreasing it when the vehicle deviates from the trajectory during turns, thereby changing the turning radius without relying on steer-by-wire systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If steering angle control is used to follow the target trajectory, then trajectory followability is improved, but the driver feels a sense of incongruity and traveling stability is compromised
Solution Approach 1:
The patent replaces the mechanical steering angle control system with a longitudinal acceleration control system. Instead of directly controlling the steering angle to follow the target trajectory, the system controls the longitudinal acceleration of the vehicle during turns, which indirectly adjusts the turning radius and achieves trajectory following while maintaining driver comfort and stability.
Solution Approach 2:
The patent changes the control parameter from steering angle to longitudinal acceleration. By controlling longitudinal acceleration during turning maneuvers, the system modifies the vehicle's turning radius dynamically, enabling trajectory followability improvement without the adverse effects of direct steering angle control on driver comfort and stability.
2Manufacturing precision
If steer-by-wire system is used to control actual tire steering angle independently, then trajectory followability is improved without changing steering angle, but device complexity increases
Solution Approach 1:
The patent replaces the complex steer-by-wire mechanical system with a simpler longitudinal acceleration control system. Instead of independently controlling the actual tire steering angle through a complex mechanical decoupling system, the patent uses longitudinal acceleration control to indirectly adjust the turning radius, achieving the same trajectory following effect with significantly reduced system complexity.
3Manufacturing precision
If longitudinal acceleration is increased during turning to decrease turning radius, then trajectory followability is improved, but traveling stability may be compromised when lateral slip angle is large
Solution Approach 1:
The patent implements a feedback control mechanism that monitors the vehicle's actual trajectory and turning state during maneuvers. Based on the detected deviation from the target trajectory and the current turning radius, the system dynamically adjusts the longitudinal acceleration to achieve the desired turning radius adjustment while maintaining traveling stability, even when lateral slip angle is large.
Data Source
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AI summary
Provided are a vehicular motion control device and method such that, even when a vehicle is turning, the target trajectory can be followed while maintaining traveling stability, with a reduced sense of incongruity felt by the driver. This vehicular motion control device is equipped with: a target trajectory acquisition unit 1a that acquires a target trajectory for a vehicle to travel; and a speed control unit 1ca that increases or decreases the longitudinal acceleration generated in the vehicle, the longitudinal acceleration being positive in the vehicle travel direction. If the vehicle deviates from the target trajectory during turning, the speed control unit 1ca performs longitudinal acceleration control to increase or decrease the longitudinal acceleration.