Research On Intelligent Prosthetic Path Planning Method Based On RRT Algorithm

The intelligent prosthetic arm is an important research content in the field of robots.It has the characteristics of flexible movement,strong obstacle avoidance and easy control.The research on its path planning can solve problems which encountered in the fields of industrial production,medical care and people's daily life.Therefore,research on intelligent false arm obstacle avoidance path planning technology has important theoretical significance and practical application value.In this study,the seven-degree-of-freedom intelligent prosthetic arm developed by the research group is used as the object.And the path planning method based on Rapidly-Exploring Random Trees(RRT)algorithm is studied.Firstly,the kinematics analysis of the intelligent prosthetic arm is carried out.The coordinate structure of the intelligent prosthetic link is established by using the object pose description method in Cartesian coordinate system.The standard(Denavit-Hartenberg,D-H)modeling method is introduced to establish the pseudo-arm seven-degree-of-freedom motion,and obtain the seven-link homogeneous transformation matrix.Based on the kinematics model,the positive kinematics equation of the intelligent prosthetic arm is derived.According to its own configuration characteristics,the inverse kinematics solution is solved by the pose separation method.And the solution results are verified by the MATLAB Robotics Toolbox.Secondly,the intelligent prosthetic arm is studied based on RRT algorithm path planning aiming at the shortcomings of traditional RRT algorithm,such as strong randomness and low search efficiency.Because of these shortcomings,an improved path planning node expansion method is proposed by introducing the guiding factor on the basis of the original.Therefore the algorithm generation path is quickly extended from the initial position to the target point,thereby improving the path planning efficiency.According to the characteristics of the intelligent artificial arm structure,the cylindrical envelope method and the enveloping sphere method are used to simplify the artificial arm model to solve the collision detection problem between the false arm and the obstacle.The obstacles are avoided by using a preset collision detection method to avoid the defect of partial deadlock caused by over-booting,thereby improving the speed of obstacle avoidance.The two-point direct connection algorithm is used to smooth the obstacle avoidance path,shorten the length of the false arm motion trajectory,improve the smoothness of the trajectory and improve the calculation efficiency of the inverse solution.Finally,the software and hardware control platform are built.And the path planning simulation based on RRT algorithm is applied to the end position of the intelligent prosthetic arm in the three-dimensional environment using the MATLAB Robotics Toolbox.Using the Visual Studio 2013 software programming platform,the intelligent prosthetic path planning control program is programmed to control the prosthetic arm to plan a collision-free path from the initial point to the target point.The experiment verifies the correctness of the model and the rationality of the algorithm improvement.