Study On Route-tracking Controlling Strategy Of Auto-Guided Vehicle

Automatic Guided Vehicle (AGV) is an automatic transportation vehicle without driver, and with a certain amount of weight it can travel between the departure and the destination. It covers the technologies of Optics, Electronics, Acoustics and Computer Science and other advanced theories and technologies in the current scientific and technical fields, and it is one of the offshoots of mobile robot. Tracking control is the key technique among the researches of the AGV, it is very important to design a control system that has the following characteristics: small tracking error, quick dynamic response, adaptability to complicated circumstances and robustness and so on.AGV kinematics model is founded based on AGV's structure features and relative motion relations with lane. By analyzing the static feature and dynamic feature of driving system, driving system identify is finished and the transfer function is obtained, finally the state space model is founded. The analysis results of control system show that it is controllability, absorbability and critical steady, so it can become closed loop steady by means of the pole configuration.With the theory of engineering design method, a PD-Controller is serried in the first-channel of the control system, and the optimal parameters are obtained. Simulation results show that the designed controller can improve the steady and the characteristics of the control system, such as quick dynamic response, adaptability to complicated circumstances and robustness and so on. But the controller cannot have small tracking error to meet the high precision requirement.In order to resolve the shortage, the thesis chooses the linear quadratic form optimal controller design scheme by applying linear state feedback control of the modern optimal control theory. With the analysis of the step response diagram and poles diagram, the optimal state feedback array is obtained and finish designing of optimal controller of AGV. Simulation results show that the designed controller can realize accurate and stable navigation control and it has the well steady-state characteristic and adaptability and can meet requirement of AGV's tracking control in small deviation. However, it has the shortage of slow adjusting when the vehicle is in the big deviation condition. In order to resolve the shortage, the thesis researches on fuzzy controllerbelow. It makes the linear function of lateral difference and orientation difference as one input and makes its change ratio as another input to design fuzzy controller with two inputs and one output. Simulation results shows that the fuzzy controller can make system converging quickly in big deviation conditions but the control effect is worse in small deviation conditions because the control rules cannot consider all conditions.In order to resolve the shortage of singer controller, the thesis chooses threshold switch method to carry out the multiple controllers in tracking controlling of AGV. The fusion makes two controllers not only working in good performance but also having the little shake when switching.