Design And Research On Control System Of Planetary Sampling Robot

Although human science and technology are constantly improving,there are still many unknowns in the world waiting for us to explore.The universe and its celestial bodies carry too many questions waiting for us to answer.Planetary detectors are pioneers in the exploration of the universe by human beings,and the sampling manipulator is an important part of the planetary detectors.Its research is of great significance.For this reason,this paper is based on the sample robot arm prototype of the laboratory,and its trajectory planning and trajectory tracking control are mainly explored.The trajectory tracking control method of the research and analysis is not only limited to the sampling robot arm,but also applied to the more general industrial robot arm.And it is meaningful.Firstly,according to the proposed design requirements,the overall structure of the sampling robot arm is designed.The joint drive motor and reducer are selected and analyzed.The modular design concept is used to design the waist,shoulder and elbow joints.In the establishment of the mathematical model,the D-H coordinate model of the sampling manipulator and its corresponding D-H parameter table were established according to the classical Denavit-Hartenberg method,and then the positive and inverse kinematics of the manipulator were deduced and analyzed.Lagrange mechanical method was used to establish a simplified dynamic model of the manipulator arm that ignores the wrist joint,which laid a foundation for the study of trajectory tracking control in the later period.Then the trajectory planning method of the manipulator is explored.In the joint space,the three/five polynomial interpolations and the parabola straight line segment method are studied respectively.The corresponding position,velocity and acceleration curves are obtained by Matlab.Then the trajectory tracking control of the manipulator is studied.Firstly,an independent joint model of the manipulator is established.The coupling between the manipulators is regarded as an external disturbance.The PID control is used to simulate the position and velocity of the manipulator respectively.The analysis results show that this control method is effective for the set point control.Then a model-based control method-optimal control based on LQR was proposed.The control was deducted and the stability was analyzed.Simulink was used for simulation and a good trajectory tracking effect was obtained.After that,the trajectory tracking control of the sampling manipulator is explored using the advanced control strategy—sliding mode control.The simulation results show that although high trajectory tracking accuracy is achieved,there is a serious jitter phenomenon in the control torque,which will affect the motor and other components.Cause serious damage,A sliding mode control method based on feedback linearization is proposed for this purpose.The control is deducted and the stability analysis is performed.The simulation results show that the control method alleviates the severe jitter of the control output.Finally,based on the physical prototype of the sampled robotic arm,two motion controllers were used to build the trajectory planning experimental platform for the robotic arm.Based on the derived positive/inverse kinematics and trajectory planning algorithm,the corresponding upper computer software was written and the robotic arm was performed.Space linear and arc trajectory planning experiments were conducted to compare the advantages and disadvantages of the two controllers and to explore the possibility of low-cost control of the robotic arm.