Structural Design And Control Of Tactile Flange

With the rapid development of many disciplines such as computer science,control theory and sensing technology,the degree of automation of mechanical processing manufacturing has been rapidly improved.More and more industrial robots are beginning to be used in environmental tasks that are in contact with the environment.The position control is difficult to achieve the required job quality,and it is necessary to add force control functions to the robot.In this paper,the application of robot in grinding process is studied from the perspective of contact force measurement and its control method and the design of special end effector.A one-dimensional constant force device,namely tactile flange,is designed.A contact force control system is designed using a position-based impedance control strategy to achieve constant contact force during grinding by controlling the end position of the tactile flange.The main research work includes:Analyze the grinding process and its forces to determine the control objectives.Analyze the grinding operation process of the haptic flange,determine the transmission scheme,design the mechanical structure,calculate the parameters according to the structure and operation requirements and select the main components.Based on the tactile flange designed in this paper,four methods for measuring contact force are proposed.A double-flange compression-torque coupling sensor is designed,which can be installed between the DC motor for grinding and the support frame for the measurement of contact force and grinding torque.For the problem that the strain of the sensor elastomer is small at full scale,three improvement schemes are proposed,and the effects are calculated and analyzed.Finally,the plexiglass is selected to design the elastomer.The distribution pattern of the strain gauge is determined according to the measurement principle of the tensile force and the torque,and the circuit system of the sensor is designed.The control strategy of the tactile flange in contact with the environment is studied.The two implementation methods of impedance control are compared and analyzed.The impedance model when the end of the tactile flange in contact with the environment is established,and the position-based impedance control system is designed.The steady-state error of impedance control is analyzed.The impedance model was established by Simulink to simulate the influence of impedance parameters on the control performance.The tactile flange control experimental platform is built.Since the force sensor has a long custom cycle,the normal contact force during grinding is indirectly obtained by collecting the output torque of the servo motor.Design control program flow chart,complete the preparation and debugging of control software,and realize the grinding control of the tactile flange.Since the output torque of the servo motor is affected by its own current,the contact force between the end and the workpiece cannot be stably and accurately reflected,so that the abrasive tool generates periodic vibration when the abrasive tool comes into contact with the workpiece.The torque and axial force collected by the force sensor can be used for force feedback later,so as to avoid the oscillation problem of the servo motor output torque and achieve better experimental results.