1. Introduction to aircraft simulation turntable control system
The flight simulation turntable is mainly composed of three parts: outer frame, middle frame and inner frame. Figure 1 shows a schematic diagram of a three-axis flight simulation turntable of a certain model. The middle frame and the inner frame are closed structure, and the outer frame adopts a tuning fork structure. The inner and outer three frames are driven by a servo motor for continuous rotation. A sensor such as a gyroscope and a seeker is mounted on the inner frame for sensing the flight attitude and angular motion of the aircraft, and the I/O signals of the sensor and the controller are taken out from the base through the conductive ring, thereby collecting signals of various postures. Converted into mechanical rotation of the turntable. The physical meanings of the outer and inner three boxes respectively indicate that the outer frame indicates that the aircraft deviates from the route, the middle frame indicates the aircraft's pitch, and the inner frame indicates that the aircraft is rolling. The three frames simultaneously perform the action to simulate the true attitude of the flight in three-dimensional space.
The driving part of the system is mainly driven by a servo motor for the outer frame, the middle frame and the inner frame, and the servo motors are controlled by the respective servo controllers for motor operation. The three frames are also equipped with an inductive synchronizer and a tachometer to monitor the rotational angular position and angular velocity of the simulated turntable.
The three inner and outer frames of the turntable are independent of each other in control, so the control system adopts the scheme shown in FIG. 2. The control scheme adopts a combination of a host computer and a lower computer. A computer is used as the upper computer to monitor and manage the servo control system in real time. The lower machine is used to directly control the actuators of the three channels. Because the physical structure of each channel control loop is the same, the control relationship between the three channels is a parallel relationship.
The operation panel of the upper computer is used to set the working state of the system, and the information about the working state is displayed on the upper computer. The upper computer transmits the set command to the lower computer, and the bus between the upper computer and the lower computer exchanges data. The lower computer can convert the output according to the collected feedback signal according to the programmed control algorithm algorithm, and then control the motor through the digital/analog output to realize the real-time control of the aircraft turntable.
3.1 current loop design
The use of current loop negative feedback allows the motor to have overload capability as well as limit the maximum current value, thus protecting the motor from quick start or braking.
3.2 speed loop design
The speed loop design is an indispensable part of the position control system to ensure the static accuracy of the speed loop. The system uses a speed measuring machine as a speed feedback component to form a speed feedback loop.
3,3 position ring design
The position loop control system of the system consists of: speed loop, PWM, torque motor and speed measuring machine. Since the position loop controller is a digital controller, it can be realized by a computer. When the control system is performing speed tracking control, there is only accurate position signal, but there is no accurate speed measuring component. Therefore, the speed signal can only be obtained by the position signal difference method, and then the position closed loop control is performed, and the accuracy of the position loop is adopted. Control the accuracy of the speed loop.
4 Conclusion
In this paper, the overall control scheme of the aircraft simulation turntable is introduced, and the mathematical model of the single-frame turntable is built. The design method of the turntable controller is introduced, and the stability and accuracy of the control scheme are analyzed. The simulation model of the control system is built by MATLAB simulation platform. The simulation input signal is simulated by the example, and the fixed frequency signal and position command are sent for the simulation model. The simulation results are analyzed. The effectiveness of the control scheme is proved by experimental results.
