| The actuator is a kind of critical and executive component of the attitude and trajectory control of guided weapon,and its performance index directly determines the strike efficiency of the weapon system.With the development of the weapon system to the direction of all-electric,the electromechanical actuator is becoming increasingly widespread.During the service of advanced weapon systems such as intelligent artillery shells and electromagnetic guns,the actuator is required to have the ability to resist high overload,which brings great challenges to the reliability of mechanical transmission structure design and the stability of command tracking control in later period.The thesis focuses on the research of anti-high overload electric servo actuators,and the transmission system design,system modeling considering total factors,stable control strategy under high overload,and dynamic and static performance verification are studied.The main research contents and innovation of this thesis are as follows:(1)Aiming at the problem that the power,torque,speed and transmission ratio parameters of the servo motor of actuator are difficult to match and it is difficult to effectively exert the motor power in the full speed range.Therefore,a combined design method of the servo motor power and transmission chain reduction ratio considering the dynamic characteristics of the load is proposed.Also,the correlation criteria for multiple indicators incorperating torques-speeds behaviors of the motor and the dynamic characteristics of the reducer,are established.The matching correlation between the maximum efficiency point of the motor and the rated operating point of the actuator is obtained.The comprehensive index balance quantitative comprehensive analysis specification of actuator system is established.This research provides theoretical support for the high service performance of electromechanical actuator with high overload resistance.(2)Aiming at the problem of structural component failure of electric actuator under high overload impact,with impact resistance,service reliability,small and lightweight as the design objectives,on the basis of analyzing the dynamic evolution law of structure under impact load,a new type of antioverload deceleration transmission mechanism is designed by using triangular screw drive and combining with the fork combination.The actuator structure can avoid the damage caused by excessive bending moment of screw and shafting under high impact,and can adapt to the narrow space layout in the cabin.The finite element model of electric actuator transmission mechanism was established,the transient impact dynamic behavior of electric actuator under high impact environment was studied,and the three-step design specification of electric actuator with high overload resistance was established,including finite element modal analysis,experimental modal analysis and finite element transient impact.The effectiveness of the structural design method of electric actuator with anti-overload resistance was verified by air gun test and live shooting,and the transmission mechanism can withstand high overload impact in axial and transverse directions.It provides theoretical support for the iterative design of actuator.(3)Aiming at the problem that the disturbance characteristics of the actuator system are not clear,an accurate and comprehensive overall mathematical model of actuator was established,which considered the mathematical model of the brushless DC motor,the mathematical model of the drive,the elastic dynamics model of the screw chuck reducer,the gear pair reducer,the clearance equivalent model and the friction torque model.Based on this model,the dynamic characteristics of actuator system under high overload external disturbance and friction,clearance,i.e.,internal disturbances were analyzed.The research has shown that electric actuators experience shortterm spikes in displacement under vibration and shock,leading to sudden feedback changes in the servo system during steady state.Internal disturbances i.e.,friction and clearance in the servo transmission components lead to increased tracking delay and overshoot time in the motion process signal.It can provide a model basis for the suppression of internal and external disturbances in servo systems under high overload.(4)Aiming at the problem of instability induced by disturbance in the actuator system,based on the mixed sensitivity index and the Nyquist curve method,the PID parameter stability region construction method of actuator system was proposed.A special integrated control strategy of fuzzy control and PID control was designed to solve the disturbance problem under the interaction of nonlinear and time-varying characteristics such as friction,aerodynamic force and vibration noise of actuator system.The compound control quantity switching mechanism was used to suppress the internal and external disturbances.The conclusion shows that actuator has good stability and anti-disturbance.Aiming at the problems that the stability of actuator is difficult to be guaranteed after high overload impact and large range of damping changes,an active disturbance rejection controller including tracking differential,expanded state observer and nonlinear state error feedback was designed.The disturbance quantity under dynamic operation of actuator was estimated quantitatively by using the expanded state observer,and the effective compensation of various disturbances in actuator system was realized.The results show that the designed active disturbance rejection controller has good dynamic characteristics and disturbance rejection.(5)The hardware and software experimental platform of the overall performance test and control algorithm verification system is built.The platform can complete the testing of all the dynamic and static indicators,and can realize the system identification and control algorithm verification of the system model of the designed actuator system.The design and control method of the actuator proposed in this paper has been verified on this platform.The results show that the proposed anti-impact overload electric actuator.The design and control method can realize reliable operation and position servo closed-loop stability control under high overload and high impact conditions.The main indicators are as follows,sinusoidal instructions with an amplitude of 1.5° can achieve 25 Hz dynamic bandwidth;step instructions with a amplitude of 10° can overshoot less than 15%;rise time less than 40 ms,and maximum deflection Angle accuracy less than 0.2°.In this paper,a complete closed-loop research and design method of overload-resisting actuator,including power,control,drive,measurement and identification,is established.A standardized design specification of overload-resisting actuator is constructed.There are 133 figures,16 tables and 125 references. |
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