Research On The Control Method Of All-attitude Inertial Stabilized Platform

In order to maintain the platform in a substantially fixed spatial orientation, severe demands need to be put forward on the control system of the platform stabilization loop. In this paper, the platform kinematics and dynamics model is established and a sliding mode controller is designed to improve the transient performance and steady-state accuracy of the all-attitude inertial stabilization platform control system. And a zoning control scheme of a frame angle trajectory is put forward to avoid gimble lock. The main research work and the main results were as follows:1. In view of the structure characteristics and working principle of the all-attitude gimbal inertial stabilization platform, kinematics equations of the gimble system and the dynamics equations of each loop platform were established. According to the working principle of single-degree-of-freedom integrating gyroscope, dynamic equations were established for the three gyroscopes output axes.2. The state observer for the all-attitude platform was studied. The Luenberger observer, the proportional integral observer, and the extended state observer applied to the inertial platform was studied. The combined observer, which combines the proportional integral observer and the extended state observer, was employed to obtain the value of ? ???x, ? ???x?, ?xp? and ?xp?? accurately.3. A nonlinear integral sliding mode control method was presented to improve the transient performance of the control system. The integral item of the sliding mode surface was employed to reduce the steady-state error of the system in this method, and the properties of the nonlinear function improved the transient performance. Compared with traditional sliding mode and linear integral sliding mode, the performance of the nonlinear integral sliding mode control is more superior.4. In the case of nonzero initial values, a global nonlinear integral sliding mode surface was designed on the basis of the nonlinear integral sliding mode control. The global nonlinear integral sliding mode control system is on the sliding mode surface at the initial time, weakens the effect of initial conditions on the transient performance, eliminates the reaching phase, and makes the whole process has strong robustness. This method can overcome the shortcoming of the robustness at the reaching phase.5. In view of the coupling problem between the three channels, coupling error sources of various channels were analysed. Ignoring the small impact on the system, a control loop with the consideration of global compensation was designed on the basis of the nonlinear integral sliding mode control.6. A zoning control scheme of a gimbal angle trajectory planning of the all-attitude inertial stabilization platform is presented. A rotation strategy of the all attitude platform mounted on a missile or a rocket was brief descriped. A zoning control scheme of a gimbal angle trajectory planning is presented. Zone division, parts of trajectory planning, and the control strategy of each zone were described in detail.