Study On Control Strategy Of Path Tracking For Vision-based Navigation Mobile Robots

With the background that mobile robots are being and will be further widely applied in different areas, it is necessary to research some key technologies of mobile robot. The dissertation puts its focus on some key problems of path tracking associated with vision-based navigation mobile robot.In robot vision-based navigation, the information obtained by image sensor is processed by image processing techniques such as RGB-HSV transform, image segmentation, LSR-based approximation to obtain the mathematic model of the path to be tracked by robot. For the accurate tracking operation, the kinematics and dynamics of the mobile robot are studied to establish its mathematic model. With the acquired path data the problem of path tracking is shifted to the problem of zero steady-state error control system.Aiming at zero steady-state error, several controller structures with observer feedback are analyzed to detect the drawbacks to be remedied. With a detailed study on the characteristics of the robot model, a new zero steady-state error control structure with a stabilizing compensator using dynamic output observer is proposed. The particle swarm algorithm has been used to deduce the condition number of the eigenvector matrix directly. In order to improve the disadvantages of the particle swarm algorithm, density regulation mechanism has been used to maintain the diversity of particles and the excellent particle database has been established to accelerate the search speed. Simulation results verified the improved robustness of the proposed structure in robot tracking operation even if the parameters of controlled object are changed largely.With the problem induced from the above study that some controlled system might be unable to meet the two sufficient conditions to implement dynamic output observer, the dissertation introduces a new concept called stable transmission zeroes compensator, and theoretically proved that by applying such a compensator the controlled system can realize dynamic output observer feedback control and achieve good robustness, although with two sufficient conditions unsatisfied. Stable transmission zeroes compensator has enhanced the theory of dynamic output observer furtherly. It is proved by experiments that the stable transmission zeroes compensator can realize the dynamic output observer even if the two sufficient conditions are unsatisfied.