| With the social development and the continuous progress of science and technology, robot has been engaged in the work of human as a right-hand man. A special type of mobile robot which consists of a sequence of hinged rigid vehicles running on the horizontal plane is studied in this dissertation. The robot is drived by a car-like tractor that pulls one or more trailers. The tractor can move and turn and the trailers follow the tractor passively. This kind of system is usually called tractor-trailer mobile robot (TTMR).An important application of mobile robot is to tansport goods. The tractor-trailer mobile robot as a type of service robot has its unique advantages in carriage of goods because it can change the number of the trailers. It increases efficiency and reduces cost. The tractor-trailer mobile robot has a widely application in automated factories, airports, railway stations, shipping terminals, the nuclear environment that labor-intensive and dangerous occasion. It can transfer materials, handle baggage, transport cargo and implement other tasks. Therefore it has broad application prospects.Path tracking of mobile robot is an important problem. The purpose of path tracking is to make TTMR travel along the given geometry and satisfy certain accuracy degree, TTMR will not deviate from planning path, avoiding colliding with obstacle in obstacle environment, so path tracking control of mobile robot is a real problem. Due to the presence of multi-body of TTMR, the problem of path tracking becomes particularly complex, especially the reverse tracking is control difficulty of TTMR, attracting wide attention at home and abroad researchers.TTMR is a typical under-actuated, non-holonomic and nonlinear control system, single robot is different from TTMR in theoretical analysis, system design, motion control and other aspects, it not only has axial angle constrains of body, but also it has steering angle constrains of tractor's steering mechanism, it is difficult to apply research results of single mobile robot to TTMR directly, this robot is rearch difficulty and rearch focus at home and abroad.This paper mainly completes the following areas on path tracking control problem of tractor-trailer mobile robot. Firstly, this paper analyses the kinematics of the tractor-trailer mobile robot. Numerical model is constructed and simulations are made to verify the correctness of the model of the kinematics. It provides a theoretical basis for the study of path tracking control of TTMR.Secondly, for the path tracking control problem of trailer-type mobile robot, this paper proposes a Controller based on fuzzy-LOS, The controller can make TTMR track polygonal path, and demonstrate a good dynamic performance and tracking accuracy.Thirdly, due to the highly nonlinear and non-holonomic of TTMR, a simple traditional PID controller is difficult to achieve the tracking task, this paper proposes a controller based on PID-LOS, The controller also can make TTMR track polygonal path, and demonstrate very good motion characteristics.Fourthly, in order to verify the effectiveness and feasibility of the proposed method, experiments of TTMR are made with the protype robot and achieved a good control effect.Finally, in order to achieve real-time monitoring of the TTMR, and improve the safety of the TTMR, a Man-machine interface for the TTMR is designed and realized with C++ in VS.NET 2003. |
