Research On Control Algorithm Of Microgravity Simulating System

With the advancement of the space exploration project, space probe will play an increasingly important role. Before the launching of space probe, it's necessary that space probe should be tested on the ground. This work comes from an Aerospace Institute's project, is supported by Postdoctoral Science Foundation of China and Postdoctoral Fund of Heilongjiang Province. It focuses on the design of a control system to keep a constant tension in the cable which is connected with the space probe.The constant tension control system is one of the most important parts. It's expected to keep the tension-fluctuating of the cable to be in a small-size range when space probe is suffered from the disturbance of the pebble-ground. The design of constant tension control system is a typical servo system designing problem. In this paper, the features of several similar systems are summarized and analyzed. Then we propose the sachem of system structure and build the ideal model of the whole system to analyze.The actuating mechanism of this system is composed of torque motor, cable and buffing device. The parameters of the above have an influence on the system's performance index. In the paper, we build the model of torque motor and buffing device, and then we summarize the influence of its parameters on the system's performance index. We estimate the influence of the transverse and vertical frequency on the cable tension. In the fact, the moment of inertia of the gearing, motor and load is considerable. Besides the cable is flexible, in this paper, we analyze the transverse and vertical fundamental frequency and choose the best gear ratio. We analyze the reason of resonance then propose several methods to avoid this phenomenon.According to the power spectral density, we estimate the position disturbance from pebble-ground, and generate simulative pebble-ground position signal. And then we propose the coarse coupling solution and solve the problem of double-motor- cooperation. At last, we design the whole close-loop as a Single-loop system. After adjusting the parameters of the controller, we get a good control result.