Excavator Motion Planning And Contour Control Base On Velocity Field

Excavator is a kind of multi-functional construction machinery with a wide range of uses,and has become an important tool for the country’s modernization.However,with the continuous improvement of construction work quality and construction efficiency requirements,traditional manually operated excavators are difficult to meet the increasing requirements,and the automation and intelligent operation of excavators have become a research hotspot.In this paper,aiming at two typical working conditions of land leveling and brush slope,the velocity field theory is adopted to design the contour controller,which can improve the contour accuracy of the bucket while realizing the automatic operation of the excavator.The research content of this article on the motion planning of excavator working device includes the following four aspects.First,according to the robot theory,combined with the excavator’s geometric structure parameters,the kinematics model of the excavator working device is established;Solve the mutual conversion relationship between the four working spaces of the working device by D-H methods and geometric methods,and the bucket tooth tip and the velocity mapping relationship of the driving space;lay the theoretical foundation for the subsequent motion planning and motion control simulation.Secondly,according to the velocity field motion planning theory and design principle,design the contour controller of the operation area;use the velocity vector method to plan the air movement,and make a smooth transition between the velocity vector of the air movement and the velocity vector of the operation area.The simulation results show the moving velocity of the working device is stable and without impact,and can reduce the influence of the starting position on the contour accuracy.Thirdly,modeling the hydraulic system of the excavator working device,using the relationship between speed and displacement,and adopting the PD controller to design the position tracking control of the hydraulic system can meet the requirements of motion planning instructions;by adding coefficients to dynamically adjust the size of the planning velocity vector,The optimal solution of the coefficients is solved by iterative method to realize the flow matching of the pump valve,reduce the influence of flow saturation on the coordinated motion of multiple joints,and effectively improve the contour control accuracy of the bucket.Finally,build an excavator experimental platform,and use Open GL and MFC to develop computer software to collect experimental data;experimentally verify the kinematic model and joint motion control of the excavator’s working device.The simulation results show that the motion planning algorithm implemented in this paper based on the velocity field can ensure the smooth and stable movement of the excavator working device,and meet the requirements of the excavator’s automatic operation,smooth movement process and contour accuracy under the conditions of land leveling and brushing.It is of great significance to improve the contour accuracy of construction and realize the automatic operation of excavators.