A four-wheel independent steering-independent drive vehicle trajectory tracking method and system

Abstract

The invention provides a four-wheel independent steering-independent drive vehicle trajectory tracking method and system. The method includes: selecting a point on the target trajectory that satisfies both a look-ahead distance constraint and a radial distance constraint as a look-ahead point, wherein the radial distance constraint is the product of a radial distance coefficient and a lateral error, and the The lateral error is the shortest distance between the target track and the vehicle body reference point; according to the current positional relationship between the front detection point and the vehicle body, a circular arc trajectory passing through the front detection point and the vehicle body reference point is fitted and Calculate the radius of the arc track; calculate the angular velocity at the reference point of the vehicle body according to the set vehicle speed and the radius of the arc track; obtain the rotational speed control amount and rotation angle control amount of the wheel according to the angular velocity and linear velocity at the reference point of the vehicle body to control the vehicle Follow the target trajectory. The method and system of the invention improve the trajectory tracking accuracy, the error convergence speed and the smoothness of the vehicle body during the tracking process.

Description

technical field [0001] The invention relates to the technical field of vehicle automatic control, in particular to a four-wheel independent steering-independent drive vehicle trajectory tracking method and system. Background technique [0002] Vehicle trajectory tracking is to control the vehicle to quickly converge to the target trajectory and move along the target trajectory given a target trajectory. The current trajectory tracking algorithms can be roughly divided into three categories: model-based control algorithms, feedback error-based control algorithms, and geometric relationship-based control algorithms. Model-based control algorithms need to establish accurate vehicle kinematics and dynamics models, taking into account the impact of tire cornering force and slip rate on trajectory tracking performance. The control algorithm based on feedback error does not need to establish a system model, and the controlled system is regarded as a black box, and the controlled q...

AI Technical Summary

Problems solved by technology

When the lateral error is large, the vehicle body will have a large yaw rate, causing the vehicle body to swing in and out near the target trajectory, the error convergence time is long, and the trajectory tracking error is large in the initial stage

In addition, the traditional pure tracking method usually adopts a fixed look-ahead distance constraint, which cannot automatically adapt to the curvature change of the target trajectory, resulting in the phenomenon of "curve edge cutting" at the curve

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