Research On Variable Physical Damping Control Method Of Robot Joint Driver

At present,more and more robots enter people's lives and work,so the need for safety between robots and people,robots and the environment are getting higher and higher.It is the key to developing robotic joint drives with ontological flexibility to become flexible robots.At the same time,due to the safety,interactivity and energy efficiency of the flexible joint drive,the development of the robotic joint drive system with the flexibility of the body has attracted more and more attention.However,introducing flexibility in the joint drive system will increase the oscillation of the system and reduce the mechanical bandwidth of the system,making system control more complicated.With the support of the project "Research on the design and drive control of variable damper drive mechanism",this paper is devoted to the study of a physics-damped robot joint drive,which is used to model the dynamics,variable damping and vibration,and achieve damping and position coordination control.Firstly,in order to solve the problem that the introduction of elastic elements in the traditional joint drive makes the system difficult to control,this paper proposes a new type of Variable Viscous Damping Actuator(VVDA)based on hydraulics.The hydraulic drive unit in which the elastic drive SEA is placed in parallel can change the effective area of the orifice by adjusting the damping motor and the crank link,thereby realizing the physical viscous damping.Then based on the dynamic modeling of the traditional tandem elastic actuator SEA established by the Lagrangian method,the dynamics of the variable physical viscous damping compliant actuator is modeled and a simple dynamic simulation is carried out.The results show that changing the viscous damping of the VVDA system can effectively adjust system performance.The Variable Physical Viscous Damping Drive(VVDA)is designed to adjust the dynamic perfonnance of a compliant drive with hydraulic viscous damping.In this paper,through the analysis of the hydraulically variable physical viscous damping system,a variable damping control law that can suppress the vibration of the system by changing the viscous damping is designed.At the same time,a PID-based double closed-loop damping hole opening degree controller is designed for the damping system,so that any given viscous damping can be realized.Research shows that the hydraulically variable physical viscous damping system can effectively suppress the system vibration caused by the elastic components.The series of elastic elements are introduced into the drive to separate the input shaft from the output shaft,and only the input shaft is directly controlled by the motor,which has the characteristics of nonlinear under-actuation.Therefore,the trajectory tracking and damping/position joint control of hydraulically variable physical viscous damping actuators are studied.Firstly,a hierarchical back-control strategy is applied to the traditional PD controller to control the trajectory tracking of the main drive motor by using the system layering and back-stepping method.Finally,the joint is designed based on the requirements of safety and high precision tasks.Drive damping adjustment and position control cooperative control method.Finally,the simulation and experimental verification of the designed driver and control strategy can achieve the desired results.