Simulation Study On Trajectory Tracking Of Excavator

In recent years,the intelligentization and automation of excavators have gradually applied to more fields.Especially in infrastructure,water conservancy and hydropower,rescue and disaster relief are becoming increasingly prominent.However,the excavator working device system has the characteristics of multivariable and strong coupling.Therefore,the establishment of accurate system models and the realization of stable and fast trajectory tracking control are facing huge challenges.This article takes Swe85 excavator as the research object.Establish excavator kinematics and dynamics models.A trajectory planning analysis was carried out.A nonlinear PID controller is designed.Then research the excavator's fixed point digging operation.The trajectory tracking of the working device of the excavator under different load conditions is realized.The specific work is as follows:Firstly,analyze the kinematics of the excavator working device.First,the D-H method was used to establish the spatial coordinate model of the excavator working device.Then,according to the D-H parameters of each link,the posture relationship between each joint is obtained.Then through the homogeneous transformation matrix.The posture of the excavator working device relative to the excavator body is obtained,and the forward kinematics equation of the excavator working device is derived.Finally,the inverse kinematics equation of the excavator working device is obtained by analytical method.Secondly,dynamic analysis of excavator working device.The more general hydraulic cylinder transfer function model is given.At the same time,the other parts of the system are reasonably simplified.The control system models of boom,stick and bucket are obtained.Aiming at the selection of controller parameters.A parameter tuning method combining optimization function and NCD module is studied.The optimal parameter values are obtained.Completed the design of the working device control system.The simulation results show that the designed controller not only improves the speed,but also improves the stability of the system and has a good effect.Thirdly,the trajectory tracking of a single joint is studied.Input a single signal into the stick joint control system.The system's response performance to different signals is analyzed.The combined signal is then used to simulate the process of digging the stick.The performance of the stick trajectory tracking system is analyzed.On this basis,the trajectory planning analysis of the excavator's fixed-point digging operation is carried out.The inverse solution of the working device is obtained according to the digging trajectory of the tip of the tooth tip of the excavator bucket.The time-optimal joint angle and angular velocity trajectory are obtained.Finally,in the form of compound excavation,the trajectory tracking study of the shortest time for fixed-point pit excavation under no-load conditions is completed.Finally,the digging operation under no-load conditions does not accurately reflect the actual working conditions.The load increase during the simulation of digging operation was designed,and the load change curve was designed.At the same time,it optimizes the problem of slow system stability after adding load.A method to determine the value of PID following load changes is studied.Apply the shortest time digging trajectory to the actual digging process.It solves the transition problem from theoretical research to practical application.The performance parameters of the system are closer to the actual mining process.From the simulation results,it is found that the joint trajectory and the position of the tip of the bucket tooth tip can track the target trajectory quickly and stably.It can achieve high-precision excavator trajectory tracking requirements.