Control Research Of Trajectory Tracking Based On AS-R Moblie Robot

Generally speaking, the mobile robot,what we referred, is a kind of machine system which is used to complete the scheduled work. It can be put in a complex and unknown environment, and can get the environment information and its own state information by the sensor, and to complete a set of independent movement. Whether in developed countries, or developing countries, mobile robot began to act on the stage of history. It not only be used in industrial production,daily life, education and scientific research, but also be used in military and aviation. In recent years, a large number of scholars and researchers start to study the theory of environment modeling, path planning, orientation, navigation, obstacle avoidance, trajectory tracking and more information fusion about mobile robot, and have got great achievements.AS-R is a kind of indoor mobile robot,which is developed by Shanghai GRANDER company and applicable to teaching. AS a kind of innovative research platform, in a certain sense, it has a certain openness, and has a broad space to study.In this paper, AS-R is treated as the study object, and its related issue about trajectory tracking is studied.The following is the main part of this paper.(1) Building the kinematics model.After understanding the basic system of AS-R mobile robot,its dynamic system is regarded as the key of this paper,and then build a kinematics model to describe the relationship between speed and displacement.and write out the kinematics equations, the posture error equation and its differential equation.(2) The choice of control algorithm. In view of the outstanding advantages of sliding mode variable structure control,such as the request for the mathematics model of the controlled object is not tall and it’s not sensitive on the outside interference and parameters change, so it can be viewed as the main algorithm for the trajectory tracking control of the robot.(3) Design for the sliding mode controller.To the characteristic of the kinematics model:multiple input and non-linear,according to the Backstepping theory to design a reasonable switching function. Then, under the guidance of the trending law theory, design the control law for sliding mode controller. So, the mobile robot can achieve the tracking to some trajectory.(4) To the analysis and study for the chattering phenomena,which often appears in sliding mode control method, fuzzy control can be adopted to decrease chattering in this paper. The fuzzy sliding mode controller will be designed to adjust the trending parameters at real-time, so the trajectory tracking performance of the can be robot improved.Finally, achieve the simulation experiment for the conventional sliding mode and fuzzy sliding mode respectively. In the experiment,track the circle trajectory and sine trajectory respectively. The results show that sliding mode control can realize the tracking of robot to the scheduled trajectory.But when the fuzzy control is put in, the tracking performance has been improved,namely not only the tracking time can be shorten, but also the error from x axis, y axis and the direction angle can be reduced, and the chattering phenomena also can be restrained obviously.