Research On Position And Attitude Detection And Control Of Magnetic Levitation Magnetoresistive Spherical Joint

With the development of technology towards intelligence and lightweight,the compact structure,low noise,and high efficiency of magnetic suspension active joints have broad application prospects in intelligent robots,multi-axis linkage machine tools,aerospace,and new energy fields.In the closed-loop control study of magnetic suspension magnetic reluctance spherical joints,it is necessary to first conduct a dynamic analysis of the designed model based on the magnetic field force generated after power-on and the control current,and derive its motion equations to provide a foundation for closed-loop control.Secondly,real-time acquisition of current position,angular velocity,and acceleration information is required during the operation of magnetic suspension spherical joints,requiring the selection of suitable sensors and the design of new detection methods.Thirdly,suitable control strategies can be designed based on the characteristics and dynamic models of magnetic suspension spherical joints to achieve closed-loop control of their motion.Finally,the designed control strategy needs to be experimentally verified,and the analysis of the experimental results can further improve the control strategy,enhancing the accuracy and response speed of closed-loop control.The research process of this paper includes the following aspects:(1)This paper provides a detailed introduction to the structure and components of the magnetic levitation magnetic reluctance spherical joint under study,including their parameter dimensions and functions,and describes the operating principles once they are combined.A coordinate system is defined to describe the rotor’s spatial motion state for subsequent sensor signal acquisition and conversion.Suitable analytical algorithms are selected based on different detection methods and motion characteristics to solve the pose and obtain the rotor’s precise motion trajectory.(2)Based on the electromagnetic force generated on the rotor teeth due to the stator magnetic poles’ energization,the mathematical models for driving and controlling the two operating conditions of the rotor teeth are established with the equilibrium suspension balance of the magnetic attractive force acting on the equator pole as the research foundation.The two conditions are:1.Rotational motion after equator pole suspension is stabilized.2.Deflection motion after equator pole suspension is stabilized.The magnetic flux density passing through the rotor teeth is continuously changed by switching the energization phase sequence.Since the rotor teeth are highly symmetrical and arranged symmetrically in a single degree of freedom direction,differential control of the current size can achieve rotation-deflection control of the suspended rotor.The magnetic field simulation of the magnetic poles after changing the energization phase sequence is verified.(3)This paper studies the detection of the spherical joint’s motion pose in three-dimensional space,analyzing that the joint rotor’s motion information in six degrees of freedom is provided by three-axis acceleration and three-axis angular velocity.The conversion relationship between acceleration,angular velocity,position,and attitude is described in detail.A pose sensor is designed and selected to provide the detection signal required for the pose conversion,and wireless signal transmission to the computer is established.A display window that meets functional requirements is designed to provide relevant information for real-time monitoring of the rotor’s motion pose.(4)The closed-loop control of the magnetic levitation magnetic reluctance spherical joint is studied.Based on the joint’s working principle and mathematical model,the PID control simulation is conducted.In a single degree of freedom direction,the position feedback and the change of electromagnetic force are obtained by taking the difference between the given displacement and the input displacement.A experimental platform is established to conduct static and dynamic experiments under different operating conditions of the prototype,analyzing the existing errors and deficiencies during the process.This paper follows a research process that includes the study of the magnetic levitation magnetic reluctance spherical joint’s structure,material selection,mathematical model establishment,simulation analysis,detection method research,closed-loop control simulation,and prototype experiments for analyzing the joint’s motion pose under specific operating conditions.Experimental research shows that although there are still some shortcomings,the research approach’s rationality and feasibility are confirmed.