A Milling Mechanics Model And Speed Controlling Of A Pneumatic Motor In A Disassembling Robot

In nuclear accident emergency responses,rescue robots with high-precision dismantling operation and irradiation resistance are required.Widely applicable electric milling and pneumatic milling solutions for milling and dismantling system in rescue robots with dismantling operation in high irradiation environments are proposed in this paper.An electric milling system and a pneumatic milling system are overall designed.A disassembling milling force model is established.Pneumatic milling speed control simulations and experiments are carried out.Main study results are shown as follows:(1)A milling system in a disassembling robot is overall designed.Its dismantling workflow for end-effectors in the system is developed.A solution is designed including a tool drive,a tool cooling and lubrication unit and an automatic tool loading and unloading unit and milling end-effector.(2)A prediction model for stainless steel disassembling milling force was developed using experimental empirical method.Using F and t method disassembling milling force equations and its coefficients are tested respectively.Test results show that experimental variables corresponding to the coefficients are independent and these coefficients have a significant linear relationship with the dismantling forces.And prediction equations have a high degree of confidence.The degree of confidence for milling combined forces that fit the equations is reaching94%.(3)A pneumatic milling system is designed and theoretically analyzed.Air compressors,air supply triplets,oil misters,exhaust throttle valves and air motors are selected.By studying internal structural parameters of the air motor and variations of the gas pressure equivalent in each chamber,differential equations of the gas pressure in each chamber are established.(4)A model about pneumatic milling speed is established using the equation about the relationship between air spindle flows and speeds and a mathematical model of controlled air flow.Output speeds are controlled by using a fuzzy PID controller.Control model simulation results show that fuzzy PID can effectively reduce the response time and overshoot for the speed model.And its speed controlling can be effectively realized even with the interference of alternating loads.(5)A pneumatic milling experimental platform is built to perform milling disassembly experiments on stainless steel based on different inlet pressures and disassembling depths.Experimental results show that the faster the spindle output speed is,the better the milling effect is,and under the same inlet pressure the deeper the milling depth is,the more obvious the phenomenon of pneumatic milling vibrations are.In order to measure inlet pressures and the output speeds which are brought into the speed model to obtain the required simulation parameters,the air spindle speed measurement platform are built.Research results in the thesis,which have been applied to a project on the National Key Research and Development Program,will be a foundation for the development of a complete dismantling robot machine.