Robot Polishing System Based On Auto Disturbance Rejection Control

Robot constant force polishing control is widely used in industrial production.Constant force polishing mainly uses robot forward and inverse solution and force analysis for precise feedforward control.However,during the force control process,the robot will be affected by forces from multiple directions from the outside world.Interference causes fluctuations in the grinding force.Therefore,during the robot’s constant force grinding process,the following problems need to be solved:(1)Choose a suitable force sensor.The force sensor is used to sense external force fluctuations.It is necessary to select a suitable force sensor according to the force fluctuation range,frequency and accuracy requirements,and conduct test analysis to ensure the accuracy of the measurement during the robot polishing process.Sex.(2)Design the robot end grinding device.The grinding head in this experiment adopts a detachable diaphragm pneumatic grinding head.In order to ensure the grinding effect,the grinding time of the grinding head must be perpendicular to the normal line of the grinding plane.The Z-axis direction of the force sensor is coincident with the center line of the grinding head to ensure the stability of operation,and at the same time,the force sensor is compensated for gravity to improve the reliability of the data collection of the force sensor.(3)When the robot moves from the free space to the constrained space during the grinding process,at the moment when the end grinding head is in contact with the grinding workpiece,because the rigidity and actual position information of the grinding workpiece cannot be determined,the speed will be too high during the grinding contact.A certain impact force is generated due to fast and other reasons.To solve this problem,a smooth and flexible force can be used to complete the contact transition process,so as to achieve the purpose of alleviating the impact force.(4)In the polishing process,due to external interference and the uncertainty of the polishing environment,the data collected by the force sensor may be distorted or mixed with redundant disturbances.The controller composed of auto disturbance rejection and fuzzy control can be used to control the collected data.The force data is used to estimate the external disturbance and compensate for the redundant disturbance information.At the same time,fuzzy control is used to help improve the adaptability of the robot in polishing different objects by changing the impedance parameters.Through this method,a transition process can be added to reduce the force impact when the robot touches the polishing surface,and at the same time,the force following accuracy of the robot and the robustness of the constant force following process can be improved,and the force error can be controlled within 2N.On the other hand,in order to respond to changes in the polishing environment Or the force following the change of the grinding object,the impedance parameter in the impedance control can be adjusted according to the force error,which improves the adaptability of the robot to the external grinding environment.