Research On Trajectory Planning Of Parallel Pointing Mechanism Based On Improved B-spline Function

Parallel pointing mechanism refers to a mechanism that realizes the functions of aiming,positioning and tracking the target under a certain environment and load.Modern research puts forward requirements for parallel pointing mechanisms to achieve faster and smoother passage of the position points involved in the task of each drive joint under the constraints of the mechanism and movement,and these position points are planned as a trajectory,which is the trajectory The main task of planning.Its purpose is to improve the working efficiency and pointing accuracy of the pointing mechanism by planning the relationship between the track point and the time.However,traditional trajectory planning methods have problems such as large impact at the head and end points and cumbersome calculation process.Therefore,this paper focuses on the research of trajectory planning methods,taking 3-RRCPR parallel pointing mechanism as the research object,and designing a complete set of trajectory planning ideas.The main research contents are as follows:First,establish the linkage coordinate system for the parallel pointing mechanism,and establish the inverse kinematics equation of the mechanism according to the key parameters and position relationship of the mechanism,and obtain the corresponding relationship between the working space of the pointing mechanism and the joint space.On this basis,by using the concept of artificial potential field method,the end space of the pointing mechanism is replaced with the resultant potential field,a virtual simulation model of the resultant potential field is established,and the path planning algorithm of the pointing mechanism when completing the pointing task is designed.Aiming at the problems of unreachable targets and local minimums in general path planning algorithms,the traditional methods are improved to some extent,and the actual effects after optimization are analyzed by MATLAB.Secondly,through the comparative analysis of the seventh degree polynomial and the seventh degree B-spline function,an interpolation law suitable for this institution is obtained,and based on this characteristic,a hybrid interpolation of the fifth degree B-spline function and the seventh degree polynomial is proposed.method.Focusing on the problems of large impact at the beginning and end of the trajectory planning method through path points and cumbersome backcalculation process,select the trajectory planning method suitable for the organization.Then,based on the trajectory position points obtained by using the mixed difference,the objective function on time,impact,and energy consumption is established,and the NSGA-II is used to build an optimization model for the proposed new trajectory planning algorithm,set constraint parameters and perform multi-objective optimization,The Pareto frontier is obtained,and a set of optimal solutions are selected from multiple considerations,which proves the effectiveness of the multi-objective optimization results.Finally,software development and Adams simulation verification are carried out on the trajectory planning and multi-objective optimization of the pointing mechanism.Using the GUI module part of MATLAB,the virtual simulation software from inputting the value of the workspace node to obtaining the appropriate trajectory of the mechanism is designed to realize the overall trajectory planning of the mechanism.Subsequently,the Adams simulation experiment was conducted on the pointing mechanism and verified the effectiveness and feasibility of the new trajectory planning algorithm.