| The most commonly used transmission method is mechanical harmonic gear transmission for industrial robots.However,in the process of gear transmission,the flexible wheel will undergo periodic deformation,resulting in alternating stress,which can easily cause serious material fatigue damage.In contrast,the magnetic harmonic gear realizes the transmission of torque through the coupling effect between the magnetic fields.The input and output ends are non-contact transmission,which avoids mechanical wear,reduces the maintenance cost of the equipment,and enhances the reliability of the equipment.It can effectively avoid the inherent defects of the mechanical harmonic gear,and is likely to become the main realization form of the robot precision reducer in the future.Therefore,this paper studies some key properties of magnetic harmonic gears as follows:Firstly,the operation principle of magnetic harmonic gear is expounded.Combined with the mechanical structure and magnetic circuit structure of magnetic harmonic gear,to introduce the magnetic field modulation mechanism and working theory of magnetic harmonic gear.The cause of working torque and pulsating torque of magnetic harmonic gear is further introduced,and the key factors affecting pulsating torque are discussed.The torque transmission of the magnetic harmonic gear is mainly through the magnetic field,so it is necessary to analyze the magnetic field of the magnetic harmonic gear.For the magnetic field analysis of magnetic harmonic gears,the theoretical analysis method is used here.Firstly,the Laplace equation and Poisson equation of each region of magnetic harmonic gear are listed,and then the vector magnetic potential is solved according to its boundary conditions.Finally,the mathematical model of magnetic harmonic gear is obtained,and the validity of the mathematical model is proved by comparing with the results of Ansys software analysis.Secondly,aiming at the main performance of the magnetic harmonic gear,the magnetic field distribution of the magnetic harmonic gear is analyzed by the finite element software Ansys,and the optimal design parameters are obtained.In this paper,the performance of the type 14 mechanical harmonic gear specified in the national standard is taken as the reference object.By using the relevant electromagnetic theory and analogy method,the related performance,numerical calculation method,stability and integrated technology of servo motor and magnetic harmonic gear with the same space size are studied and compared.It is pointed out that the lack of torsional stiffness is the key factor restricting the application of magnetic harmonic gear in robot,and the research focus of magnetic harmonic gear servo control in robot in the future is clarified.Finally,taking the four-pole permanent magnet synchronous motor as an example,the magnetic gear composite motor is mathematically modeled,and then the magnetic gear is controlled and simulated by MATLAB/ Simulink simulation software to analyze the dynamic performance of the magnetic harmonic gear in the servo system.In order to obtain a more stable system,this paper introduces the theory of fuzzy PID control.The fuzzy control algorithm is superimposed on the double closed-loop speed control system of the magnetic gear composite motor.For purpose of achieving fuzzy control,firstly need to determine fuzzy variables and membership functions and create fuzzy rules.Then the Simulink is used for simulating and analyzing the speed control system of the magnetic harmonic gear composite motor.The results show that compared with the traditional PID control,the magnetic harmonic gear composite motor under fuzzy PID control has better dynamic performance. |
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