Design And Research Of The Rate Control System Based On DSP For Turntable

The test turntable is very important equipment for testing and evaluating inertial navigation and guidance system. As the development of the testing technique, the demand of the precision and performance of the test turntable is increasing rapidly. Generally speaking, the precision of test equipment should be ten times than that of the tested instrument. Otherwise, it will be of nonsense. In this paper, the software and hardware of the rate system of turntable is designed and brought into effect based on the practical project, taking test turntable as the experiment platform. In the last chapter, the cancellation of periodic disturbances is studied.In the light of the high demand of the performance of rate control system of turntable, the overall structure of the control system is designed based on the PLL (phase–locked loop) technique which is used widely in communication system. The PLL in this paper consists of the phase detector, the controller, the torque motor and the feedback loop. The feedback pulse follows the phase of the command pulse to ensure the motor rotate as at the speed we need.In the section of the hardware design, DSP (the Digital Signal Processor) acts as the controller to complete the correction algorithm, and FPGA (Field Programmable Gate Arrays) complete the function of giving the command pulse, moving the phase of the pulse and detecting the phase of the command and the feedback pulse. This design makes full use of the characteristic of DSP and FPGA, and increases the operational speed and the integration level of the system it gives attention to both rapidity and flexibility. Moreover, it leaves some leeway to extend function.The correction algorithm is completed in the software of DSP. In order to make the debug procedure easier, the software of the control panel for the system is designed by VC++6.0 to setup the parameter of serial communication, and change the parameter of controller. A controller is also designed according to the performance of the rate system, and some experiments are carried out to verify the performance of the system. In order to canceling the influence of periodic disturbances to the rate smoothness of the system, an adapting algorithm of periodic disturbances cancellation which is based on internal model principle is studied. This method can cancel completely single-sinusoidal signal and multi-sinusoidal signal, and even time-varying sinusoidal signal. Furthermore the ripple phenomenon of the estimating frequency is studied when the estimated frequency of disturbances changes rapidly, and some solutions are put forward. Simulations demonstrate the performance of the algorithm, the ability of this algorithm to identify the frequency of periodic disturbances and to reject periodic disturbances with uncertain frequency.