# Constant Force Control of Centrifugal Pump Housing Robot Grinding Based on Pneumatic Servo System
###### Abstract
[17] proposed a new selective force control method based on machining allowance considering area division and developed an adaptive impedance controller based on a neural network on-line compensation algorithm (AICNN), which was used to improve the robot grinding accuracy of complex curved blades. [PERSON] et al. [18] proposed a grinding force control method for light robots based on the model predictive controller, which used seven force or torque sensors to improve the force control sensitivity. [PERSON] et al. [19] proposed that robot grinding would become a key solution for the processing of complex parts, towards intellectualization. In recent years, the contact force in the robot working process has always been a research hotspot. [PERSON] et al. [20] used the hybrid force or motion control method to study the movement trajectory and force changes of the robot based on the dynamic motion primitives (DMP) framework. [PERSON] et al. [21] studied the vibration suppression method of force control for the grinding of large thin-walled shells. [PERSON] et al. [22] proposed an adaptive neural network control scheme to study the force control stability of a rigid manipulator with input saturation, full order state constraints, and unmodeled dynamics. In order to eliminate grinding marks, [PERSON] et al. [23] used the active force control method composed of the force or position of a six-dimensional force torque sensor and a PI or PD controller, and used the passive force control method of the PID controller of a one-dimensional force sensor to improve the accuracy and efficiency of force control. [PERSON] et al. [24] proposed a novel motion-force control strategy under the framework of a projected current neural network (RNN), which is used to study the accurate position-force control of a manipulator with redundant degrees of freedom (DOF). [PERSON] et al. [25] used the methods of the explicit force control based on position and tilting polishing tool with elastic sponge plate to control the polishing force. [PERSON] et al. [26] proposed a method to calculate the driving torque of the robot joint based on the form-shaping motion of the robot, so as to realize the control of cutting force. [PERSON] et al. [27] constructed the impedance dynamics of a robot using the Maxwell model of plastic deformation. [PERSON] et al. [28] used the hybrid force or position controller of ANFIS \(-\) PD + I (AFSPD + I) to effectively control the unknown dynamics of a robot with external interference. [PERSON] et al. [29] designed a force observer based on the dynamics of the centroid joint, which was used to discuss the estimation of the contact force at the end effector of a space robot. To achieve the ability of robot grinding to adapt to unknown environments, many scholars have studied the constant contact force control from different angles. In the production and processing of centrifugal pumps, the grinding and polishing of the centrifugal pump is a key process in the manufacturing process, the cost of which accounts for 30% of the total cost. Robot grinding and polishing is an effective way to reduce costs and improve efficiency. In order to ensure the consistency and uniformity of the surface effect after the grinding and polishing of the centrifugal pump, the contact force should be controlled as a constant force and the direction s should be parallel to the normal direction of the contact surface. Active compliance control is a way to accurately transfer force to the control system. Through the adjustment of the control algorithm, error compensation for position and force can be carried out, respectively, which can respond to the change in force in real time and track the desired contact force [30; 31; 32]. A core problem in the process of grinding and polishing is the control of the force, which is easily disturbed and can change suddenly.