Research On Load Simulation And Loading Control Methods For Cockpit Over Electromechanical Actuator

A load simulator is a kind of ground-based,semi-physical simulation test equipment that is widely used in the aerospace field.With the development of aviation,the accuracy and response speed of the cockpit canopy maneuvering servo system have gradually improved,and the performance requirements of the load simulator are also increasing.In order to accurately test the performance of an aircraft cockpit cover electromechanical actuator,this paper takes the electric load simulator developed by the group as the research object and designs a new convergence-law sliding mode controller with inertia identification and disturbance compensation that can realize accurate control under the interference of excess torque,stiffness,inertia,and other factors and improve the anti-disturbance capability on the basis of simulating complex load performance.The main research contents are as follows:(1)Firstly,the structural components and operating principles of the electric load simulator and the cockpit cover electromechanical actuator are introduced;the coordinate transformation principle of the permanent magnet synchronous motor and the voltage space vector pulse width modulation technique are studied;the advantages and disadvantages of the magnetic field directional control and the direct torque control are compared and analyzed;and then the mathematical models of the electric load simulator and the cockpit cover electromechanical actuator are determined,respectively.(2)The effects of the permanent magnet synchronous motor body,excess torque,and mechanical structure parameters(stiffness and inertia)on the loading performance of the developed electric load simulator are analyzed,and a finite element model of the permanent magnet synchronous motor is established using COMSOL Multiphysics to study the effects of motor losses and torque pulsation on the motor performance.The effects of excess torque and mechanical structure parameters on the loading performance of the electric load simulator are characterized using logarithmic frequency characteristic curves.(3)In order to address the above-mentioned factors affecting the loading performance of the electric load simulator,a feedforward compensation method for the angular displacement of the electromechanical actuator of the cockpit cover is proposed to suppress the effect of the excess torque,the system stiffness is reasonably improved by introducing a precision speed stabilization buffer,the rotational inertia is identified online by using the model reference adaptive method,and a compensation method based on an exponentially convergent disturbance observer is proposed for the torque disturbance during loading.The compensation method based on the exponentially converging disturbance observer is proposed for the loading disturbance.A new convergent-law sliding-mode controller with inertia identification and disturbance compensation is designed to realize the accurate control of the electric load simulator,and the superiority of the designed controller over the PI controller is verified by simulation.(4)According to the load performance of the electromechanical actuator of the cockpit cover and the functional requirements and technical indexes of the electric load simulator developed by the group,an upper computer measurement and control system based on virtual instrumentation technology is designed,and the designed controller is integrated into the measurement and control system by Lab VIEW Math Script to complete the static and dynamic loading tests of the electromechanical actuator.The test results show that the load simulation accuracy of the electric load simulator meets the "double ten index" in both static and dynamic loading processes,which verifies the effectiveness of the designed controller.The controller designed in this paper can improve the loading performance of the developed electric load simulator and provide technical support for the development and improvement of the aero-mechanical actuator and the performance evaluation before the installation.