| The friction generated by the relative motion of the components is an interference factor for robots’ controlling and positioning accurately and cannot be ignored,which poses a challenge for the guarantee robots’ motion accuracy and the improvement of work efficiency.Especially,during the high-speed work about the dulcimer service robot,which is oriented to the precise position control,it is necessary to consider the friction effect between the adjacent joints.Under the condition of considering friction,the identification of robot motion parameters and trajectory tracking control become the key points and difficulties of related research.To this end,for meeting the high-speed motion accuracy requirements of a class of service dulcimer robots,this thesis analyzed the question of robots’ motion and dynamic response.Meanwhile,by introducing viscous Coulomb friction,it completed the study of nonlinear dynamics modeling,motion parameter identification and trajectory tracking control of dulcimer robots,as follows:1.A class of dulcimer robot structural model and its nonlinear dynamics analysis model are constructed.During the construction process,the position coordinates of the code points on the plate are defined,and the structural parameters are determined according to the playing mode of the dulcimer;the forward and inverse kinematic problems are derived and solved by the improved D-H method and the inverse transformation method,and the correctness of the solutions is verified by Matlab.Considering the friction effect combined with Lagrange equation and Coulomb friction model,the nonlinear dynamics model is established.2.A co-simulation method based on Solidworks & Sim Mechanics is proposed,which used to optimize the robot solving process from 3D model to mathematical model.A 3D model of the robot is built in Solid Works and imported the model into Sim Mechanics platform,and build a controllable simulation system.The friction moment is introduced into the simulation model,and the simulation analysis of the joint angle and angular velocity is completed in two cases considering the friction effect or not.The effect of friction on the joint moment of the dulcimer robot is studied,the maximum relative error of which can reach 7.2%.3.A hybrid control algorithm combined traditional PID control theory and fuzzy PID control theory is developed,which significantly improves the motion control accuracy of the dulcimer robot.Based on Cartesian space,the trajectory planning scheme of the dulcimer robot is discussed,and the influence of different friction coefficients on the motion trajectory is analyzed.The tracking control accuracy is studied by using the established co-simulation method of Solidwork &Sim Mechanics dulcimer robot,and the angular difference of each joint trajectory tracking is kept within 0.08 rad.4.The co-simulation method is verified by the SCARA600 robot experimental platform.The modeling of the SCARA600 robot is completed.The corresponding simulation model is built based on the co-simulation platform.Compared the robot end-effector motion trajectory between the simulation and the experiment,the maximum path deviation does not exceed 3mm,which verified the feasibility and effectiveness of the co-simulation method.Using the dulcimer robot designed in this thesis,a section of the dulcimer tune Purple Bamboo Tune is selected for performance simulation.The PID and fuzzy PID hybrid control algorithm is brought into the simulation system.The simulation results meet the accuracy requirements of the actual dulcimer performance,which verify the rationality of the dulcimer robot model. |
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