The Research On Robotic Belt Grinding Of Blade With Combination Of Active And Passive Compliant Force Control Technology

In the trend of transformation and upgrading of industry and the development of intelligent manufacturing,the industrial robotic grinding and polishing for complex surface parts,especially the aero-engine blades,has attracted widespread attention.Some research results and industrial applications have emerged in recent years,and it can replace human labor largely and improve the product surface accuracy and quality consistency.One of the key factors affecting the surface precision and consistency is the precision and uniformity of grinding force control method.At present,there are some research results focused on the robotic active and passive compliant force control,but lack of combination of the two force control methods.In this paper,a method combining the active and passive compliance control strategy,based on the active control of the six-dimensional force sensor and the passive compliance control of one-dimensional pressure sensor,was proposed to improve the surface accuracy and quality.The main contents and innovations of this paper are as follows:(1)Research on collision impact of robot based on impedance control theory.Firstly,an improved scheme for the traditional grinding and polishing machine is proposed,based on the analysis of the impedance control model and the dynamic model of polishing machine.It can effectively inhibit the instant contact vibration of robot transitioning from free to constrained space with combination of active and passive compliant force control method.Then,A series of comparative experiments were done to verify the effectiveness of the improved scheme and the force control method proposed in this paper.(2)Research on methods to improve accuracy and stability of robotic impedance control.According to the relationship between contact force and the movement of robot center point(position or speed),a Kalman filter information fusion method is proposed.It synthesizes signals from six-dimensional force sensor(ATI)and one-dimensional pressure sensor(SSM500N)which can improve the measurement accuracy and stability of normal grinding force _nF during grinding.Thereby the accuracy and stability of impedance control is improved.The validity of the method proposed above is verified by Matlab simulation and experiments.(3)Through several grinding experiments with different force control methods,including robot position control(without force control),active force control,passive compliant control and the combination of active and passive compliant force control.It is verified that the combination of the active and passive compliant force control methods proposed in this paper can improve the grinding and polishing quality in the grinding process of robotic belts grinding system.