Vibration Suppression Trajectory Planning And Inversion Tracking Control Of Double-link Flexible Arm

With the rapid development of robotics industry technology,more and more fields have introduced robots to replace humans.Robot kinematics,dynamics,trajectory planning and control methods have become hot research issues in countries around the world.Flexible arms can meet more work requirements and can adapt to more complex work environments,so they are more used in the aerospace field and precision industrial robots.The flexible arm has a light mass and a large load,which can better complete space tasks.Flexibility will bring vibration,so the flexibility of the robotic arm cannot be ignored.In the space environment,the impact of gravity is very small and the damping is almost no damping.Once vibration occurs The deformation is difficult to stop by itself,which greatly affects the accuracy of the work and even causes safety problems.Therefore,it is necessary to analyze the vibration characteristics of the flexible arm and plan a reasonable trajectory and trajectory tracking research.The mechanical arm is composed of an arm and a joint.In order to better complete the task,a flexible structure needs to be introduced.Both the flexibility of the arm and the joint will cause vibration and deformation,which greatly affects the positioning accuracy.This paper takes the two-link flexible arm as the main research object,and aims to improve the vibration suppression effect and tracking ability.The simulation and theoretical analysis are combined to conduct kinematics,dynamics and vibration characteristics analysis,trajectory planning,control methods,etc.Research on the following aspects:(1)According to the needs of different work tasks,the flexible arm is mainly divided into three configurations.This paper uses the Lagrangian method to solve the dynamic models of the three configurations in detail.The analysis method and simulation are combined to analyze the vibration characteristics of the flexible arm in detail.First calculate by analytical method,and then change the stiffness coefficient of the flexible joint under the condition of applying variable driving force.Through simulation,it is found that as the flexible stiffness of the joint continues to increase,the difference between the joint angle and the arm angle becomes smaller and smaller,and the joint is more flexible.The impact is getting smaller and smaller.The Young's modulus of the material determines the flexibility of the boom.The larger the Young's modulus,the stronger the flexibility of the boom.The deformation at the midpoint of the boom is taken as the research object.Simulation shows that as the flexibility of the boom increases,the boom vibrates The deformation also increases accordingly.(2)According to the results of the vibration characteristics analysis,combined with the curve planning method,the vibration suppression of the flexible boom is studied.The first is to combine the advantages of the trapezoidal curve and the trigonometric function curve to construct a sine-trapezoidal basis function curve.The time parameter and peak value parameter can realize the adjustment of the basis function curve.Then improve on the basis of the polynomial interpolation function,combine the polynomial interpolation with the sine-trapezoidal basis function,use the coefficients in the polynomial as the coefficients of the basis function,and superimpose multiple groups of basis functions to obtain the peak value is not high and The smooth and continuous superposition curve is used as the angular acceleration planning curve of the flexible arm,and the vibration suppression effect is verified by simulation,and the simulation results are compared with the fifth-order polynomial planning simulation results under the same conditions.The simulation results show that the elastic vibration of the flexible boom is greatly reduced after the angular acceleration is planned,and compared with polynomial interpolation planning,the vibration suppression effect of the boom is better.This is more important for the research on the vibration suppression of the complex multi-link flexible boom system.Great value.(3)There are many control states in the flexible manipulator system,which is an under-actuated system.In view of this characteristic,in the trajectory tracking research,this paper chooses to adopt the inversion control strategy.Firstly,the two-link manipulator is derived from the dynamic model.The state equation of the system,the system contains 4 state variables,and then 4 intermediate virtual control variables are designed.According to the Lyapunov scalar function,the inverse control law is obtained and the stability is calculated.Take the two-link flexible arm as the research object for simulation research,impose external interference,and track two different types of curves,which are a smooth sine curve and a fast-changing polynomial curve.Observe the accuracy of trajectory tracking and speed tracking.And speed,the results show that after applying the inversion control strategy,the tracking accuracy and tracking speed of the two curves are better,indicating the effectiveness of the inversion control strategy for the flexible arm system.The research content of this paper can provide a certain theoretical basis and technical support for the dynamic modeling,vibration suppression planning,and tracking control of the flexible arm.It has important practical significance for the use and research of the flexible arm.