Research On Trajectory Algorithm And Control Based On 3-RRR Parallel Robot

With the development of domestic industry and economy,parallel robot technology has become increasingly mature.Compared with parallel robots,serial robot have lighter loads and have defects of accumulated errors.Parallel robots are widely used in production conditions such as sorting,assembly,and lathe of the production line due to their high-speed processing,no cumulative error,and heavy load.Domestic research on parallel robots is relatively late,and the overall technology is still unable to reach the world's top level.In order to narrow the gap between domestic parallel robots and foreign countries in the industrial field,it is particularly important to strengthen the research and development of the core technology of domestic parallel robots.Trajectory planning is the underlying algorithm of parallel robots,and the study of its principles and its realization on the control system is of positive significance for promoting the development of domestic parallel robots.This topic takes the 3-RRR planar parallel mechanism as the object to study it.The main contents of the thesis are as follows:(1)The establishment of kinematics and dynamics models.The degree of freedom,kinematics and dynamics models of the 3-RRR parallel robot are analyzed using theoretical knowledge such as screw theory,geometric rod length constraints,and Lagrangian equations.(2)Research on trajectory planning algorithm.The common trajectory planning algorithms are studied.On the basis,the cubic B-spline trajectory algorithm is designed in Cartesian space,and the arc and cubic quasi-uniform B-spline transition algorithm between adjacent curve segments are studied.In order to simplify the trajectory interpolation operation of the hardware system,an asymmetric five-stage S-shaped acceleration and deceleration algorithm is designed on the basis of the seven-segment S-shaped acceleration and deceleration curve.This algorithm reduces the computational complexity of the program and simplifies the speed planning strategy,Enhance the real-time nature of the algorithm.(3)Research on processing path planning algorithm.In order to reduce the time and energy consumption of robot processing,this paper proposes a mathematical model based on the weighted sum of angle changes in joint space based on trajectory planning and dynamic analysis.An improved ant colony algorithm with an elite strategy and an adaptive adjustment function of information volatilization factor is designed to optimize the processing path,which verifies the feasibility of the algorithm.(4)The design of the hardware platform of the 3-RRR parallel robot.Using DSP+CPLD as the hardware platform,a simple control system of the 3-RRR parallel robot is built,and the hardware circuit and programming are designed.Among them,the DSP module is responsible for the rough interpolation operation of trajectory planning,and the CPLD module is responsible for receiving the rough interpolation signal to complete the fine interpolation operation.(5)Experimental simulation verification.The GUI simulation program of 3-RRR parallel robot was written on MATLAB to simulate the trajectory algorithm,and the effectiveness of the asymmetric five-segment S-shaped acceleration and deceleration in achieving smooth trajectory speed and continuous acceleration was verified.Finally,hardware simulation experiments were carried out on the DSP and CPLD modules respectively,and the built 3-RRR parallel robot platform was tested by point to point displacement,which verified the effectiveness of the hardware platform scheme and lay the foundation for subsequent research.