Trajectory tracking control method of agv system

Abstract

The invention discloses a trajectory tracking control method of an AGV system, belonging to the technical field of automatic control, including establishing a vehicle body coordinate system, calculating eccentric steering wheel coordinate values ​​and eccentric values, defining application scenarios and task trajectories, and controlling an AGV vehicle body to track a given task Trajectory three steps. First, the trajectory tracking module of the AGV control device calculates the trajectory tracking deviation based on the given task trajectory and the current AGV pose data and gives the corrected motion command, and then the pose decoupling kinematics module of the control device converts the motion command into Steering angle and forward speed for each eccentric wheel. In this way, the servo motor of the eccentric steering wheel device can drive the AGV forward according to the solved steering angle and forward speed; it can not only change the forward direction without changing the posture of the car body, but also can rotate arbitrarily while advancing along the specified trajectory The attitude of the car body gives full play to the advantages of high flexibility and stability of the steering wheel structure AGV system.

Description

technical field [0001] The invention belongs to the technical field of automatic control, and in particular relates to an AGV system with multiple eccentric steering wheels and a trajectory tracking control method for AGV position and posture decoupling. Background technique [0002] AGV, or Automated Guided Vehicle, automatically moves items from one location to another through a preset program. It is an automated, informatized, and intelligent device. The structure of the AGV system currently on the market mainly includes a differential wheel structure, a Mecanum wheel structure, and a steering wheel structure. Among them, the structure of the differential wheel is simple, reliable and easy to control, but the attitude of the car body is coupled with the forward direction, and the center of rotation must be located on the axis of the two differential wheels, so the movement flexibility is poor; the structure of the mecanum wheel overcomes the structure of the differential ...

AI Technical Summary

Problems solved by technology

Among them, the structure of the differential wheel is simple, reliable and easy to control, but the attitude of the car body is coupled with the forward direction, and the center of rotation must be located on the axis of the two differential wheels, so the movement flexibility is poor; the structure of the mecanum wheel overcomes the structure of the differential wheel However, it also introduces disadvantages such as high cost and poor motion stability; common steering wheel structures include single steering wheel and double steering wheel, among which the single steering wheel structure is essentially the same as the differential wheel structure but is more compact in structure and is mostly used in forklift systems; The rudder wheel structure can realize the change of the forward direction without changing the attitude of the car body, which has the advantages of high flexibility and smooth motion, and the cost is lower than that of the Mecanum wheel structure

Theoretically, the multi-rudder wheel AGV system represented by double steering wheels can realize the arbitrary rotation of the car body attitude while advancing along the specified trajectory, but its motion control is relatively difficult, and there are no application cases in the domestic market at present.

In addition, in order to improve the high height and large volume of the traditional rudder wheel due to the fact that the driving wheel is located directly below the steering shaft, a new type of eccentric steering wheel with the driving wheel far away from the steering shaft began to appear, which also brought new difficulties to its motion control.

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