Research On Trajectory Tracking And Obstacle Avoidance Method Of Mobile Manipulator In Complex Environment

Benefit from the rapid development of science and technology,the technology related to robotics industry has also been greatly improved,so the application of robots in production life is increasingly widespread.Fixed-base robotic arms are difficult to meet the requirements of more intelligent work in certain scenarios,and movable robotic arms have higher flexibility,so their research and application values are more prominent.For example,in the traditional construction industry,due to the complex working environment,the application of robots is restricted and still relies heavily on human labor.This paper addresses the application of mobile robotic arms in similar complex environments such as construction spraying,and completes the research on the trajectory tracking and obstacle avoidance methods for mobile robotic arms through kinematic modeling and redundancy-based path planning of mobile robotic arms.In this paper,the kinematic modeling of the adopted six-degree-of-freedom robotic arm was firstly carried out,and its linkage coordinate system was established and verified using the modified D-H parameter method.The kinematic analysis of the differential wheeled mobile robot is carried out,followed by the kinematic modeling of the mobile robotic arm formed by the combination of the two,and the kinematic relationship between the end-effector of the mobile robotic arm and the two systems is determined.By solving the pseudo-inverse zero-space joint velocity solution for the mobile robot arm redundancy degree and performing simulation verification,it is initially confirmed that the mobile robot arm constructed in this paper can track different work tasks simultaneously.For the multitask coordination problem of the mobile robot arm,a multitask priority algorithm is introduced to coordinate the different tasks performed by robot.A continuous iterative projection multitask priority method is used to solve the robot joint speed discontinuity problem of the original algorithm during task switching,and the superiority of the used method is verified through the simulation experiments of multitask switching for the robot arm.The mobile robotic arm path planning method is studied in this paper,and an improved velocity potential field-based mobile robotic arm path planning algorithm is proposed to address the problem that the original artificial potential field method cannot be applied to three-dimensional space and its defects.New attraction and repulsion velocity functions are defined to enable the algorithm to be applied to three-dimensional space,and multiple types of obstacles can be avoided.A robot action range detection method and a new temporary target point selection strategy are designed for the local minima and target unreachability problems in the original potential field method.Simulation verification of the robotic arm path planning process is carried out to confirm the effectiveness of the above method.Finally,with the fusion of improved task priority and velocity potential field control methods,simulation and experiments of the mobile robotic arm for simultaneous tracking and obstacle avoidance of the spraying trajectory were carried out,verifying the stability of the spraying work when the mobile manipulator is avoiding ground obstacles and obstacles in the robotic arm workspace,respectively.The results show that the mobile robotic arm performs well under the fusion method designed in this paper,and can continuously and stably perform the established work tasks while avoiding obstacles in the complex environment.