메카넘 휠을 이용한 전방향 주행형 AGV의 평행 주차 제어

Abstract

Automatic guided vehicle(AGV) is used mainly at narrow space industrial fields. In this environment, if the AGV is steered with idle wheel structure like a general car, the AGV has a lot of restrictions in space when its traveling path is changed. Therefore, to satisfy quick traveling with various and complex postures in narrow space, mechanism of the AGV traveling in the omni-directional direction flexibly is deeply needed. Mecanum wheel is used to implement the mechanism travelling omni-directionally. This thesis proposes PI controller to control velocities of an AGV while the AGV with four driving Mecanum wheels travels from its starting point to the place to finish parallel parking at parking space in narrow space. To do this work, first, an omni-directional mobile AGV is designed and manufactured. The AGV consists of body, driving part, sensors and control system. The driving part consists of four Mecanum wheels and four DC motor to drive them. Four ultrasonic sensors are installed on front, back, right and left sides of the AGV to detect the distance information in parking. The four ultrasonic sensors make the AGV keep the constant distance from wall. Second, kinematic modeling of the AGV is presented using pseudo inverse matrix and the dynamic modeling considering slip of the AGV with the omni-directional wheels are presented using Lagrange formula. Third, parallel parking algorithm of the omni-direction mobile AGV is presented and PI controller is presented based on the dynamic modeling integrating the kinematic modeling. A control system is developed based on PIC18F4431 to implement the design PI controller to control the velocity vector of the AGV. Finally, the simulation and experimental results are presented to prove the effectiveness and the applicability to the applicability to the practical fields of the proposed parking algorithm and the presented PI controller.