| Blade is the core part of many advanced strategic equipment,its surface quality directly determines the aerodynamic performance and service life of these strategic equipment.In order to improve the surface quality of the blade and optimize the surface performance,it is necessary to polish the blade after machining to reduce the surface roughness and meet the technological requirements.The existing artificial polishing has certain limitations,its excessive dependence on the skilled degree of workers,low efficiency,processing quality and surface consistency is difficult to ensure,but also because of the poor working environment to the workers body caused a great degree of damage.The robot with its own intelligent,efficient and other advantages,can overcome the limitations of manual polishing blade,complete the blade automation,intelligent polishing.Offline programming and force control algorithm involved in this paper are the key technologies to realize robot automation and intelligent blade polishing,which can effectively solve the problems of precision and compliance control in the process of robot blade polishing.The main research work of this paper is as follows:Firstly,the kinematic analysis and construction of Kawasaki RS20 N robot used in this paper were carried out,and the forward and inverse kinematics equations of the robot and the optimal inverse solution were obtained.Simulation and experimental verification were carried out with the help of MATLAB software and robot teaching device.It is found that the error between the results obtained and the experimental results is within 0.025 mm,which meets the requirement of positioning accuracy of 0.04 mm.The trajectory planning of linear and circular interpolation motion in Cartesian space trajectory planning is carried out based on the kinematic content.Secondly,the polishing force of the blades in the polishing process is analyzed and the prediction model is established.It is found through experiment that the force measuring element can be accurately measured by gravity compensation.The regression prediction model of polishing force was established based on orthogonal test,and the error was within 12%compared with the experimental results.Based on this,the coupling influence of process parameters on polishing force was obtained,and the influence of process parameters on the force was obtained.Then,the main power control strategy of the robot is studied,and fuzzy impedance control is proposed to solve the problems of poor trajectory tracking ability and force instability of traditional impedance control in the face of environmental changes and unknown environments.Using Simulink,a simulation platform is built to verify that fuzzy impedance control has lower overshoot,faster signal convergence time and better control effect compared with traditional impedance control.Finally,the polishing experiment of the wheel assisted by robot was carried out.The trajectory planning of the blade body was completed by the offline programming software Sprut CAM,and a reasonable compression amount was selected to polish the blade back by referring to the prediction model of polishing force.The surface roughness of the blade after polishing was detected to decrease from 1.3-2.2μm to 0.2-0.4μm,which was significantly lower than before polishing.The results show that the average surface roughness and standard deviation of the workpiece are reduced by 48% and 55% under the fuzzy impedance control,indicating that the polishing effect is better. |
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