Research On Attitude Control Thruster And Attitude Tracking Control Of Kinetic Kill Vehicle

Kinetic kill vehicle(KKV) has the advantage of tremendous momentum generated by its high-speed flight. Through independent detection, guidance and control destroy the incoming target with collision directly. In order to search target, its attitude often need adjust with wide range, when the interceptor goes into the terminal guidance stage.After located the target, attitude angle tracked angle of line of sight(LOS) with different interception strategies to achieve Zero Effort Miss(ZEM) as precise goal.Therefore, the attitude control system is critical to KKV for successful hit. As the research object,for improving performance of attitude control system of KKV, a novel solid attitude control thuster with wall attachment theory is designed. Relative research about attitude control theories and guidance law were done with considering specific issues.For achieving "Three-axis Stabilized", the form of attitude control thrusters(ACT) layout has been analyzed. According to the analysis comparative conclusions, a scheme of attitude control thruster has been determined with wall attachment theory. Its mathematical models were derived. Variation of jet angle, attachment point, collision angle,etc via structural parameters and control flow was discussed. Numerical methods had been used to analyse its dynamic switching process. According to the pressure flow characteristics of ACT, designed range of structural parameters of the actuator was obtained. Finally, the design flow chart and structural of ACT was completed.ACT consisted by electromagnetic actuator, control gas chamber and working gas chamber, its mathematical models were derived. Lots research details of ACT was discussed, Including dynamic characteristics of electromagnetic actuator by coil resistance, driving voltage, reset spring stiffness; Dynamic characteristics of jet deflection by gas flow; Influence of thrust output by the mass of ball. On the basis of research, a conclusion, delay of electromagnetic actuator was the most important factor of ACT’s delay was obtained.Due to the dynamic characteristics of electromagnetic actuator affect the response speed and control precision of attitude control system directly. An optimization algorithm of driving control amount based on the pulse width modulation(PWM) was designed for switching fast. Through the establishment of system transfer function, the influence of armature rotation angle by control input was analyzed. Designed methods of duty ratio and carrier cycle for PWM control scheme was derived, when the structural parameters was determined. Armature vibration amplitude determined by controlled amount of DC component and fundamental wave was proved. Finally, the amount of control optimization algorithm for improving the dynamic characteristics of ACT effectively was verified with the simulation and experiments.Aiming at the problem of exo-atmospheric KKV attitude tracking with the characters of constant thrust, nonlinearity, strong couplings and parameter uncertainties, a novel sliding mode controller is designed which based on adaptive backstepping theory. The attitude coupling mode is established which considers about interaction between three channels and control torque in control loop. The actual control laws and virtual control laws are derived based on the design procedures of sliding mode control and backstepping control, respectively. An adaptive method is introduced to estimate and compensate the model couplings and uncertainties, which improves the accuracy of altitude control. The pulse control laws which could use to attitude control directly, are calculated form the continuous laws with PWPF modulation. For improving accuracy, a novel controller with EDO is designed, which is currently estimating and dynamically compensating to the uncertains.The simulation results show that attitude tracking still satisfies requirements with parameters and disturbance uncertainties.Aiming at the problem of exoatmospheric KKV guidance law design for intercepting targets, a novel missile sliding mode guidance law with disturbance observer was derived base on collision course. According to steering angle of attack of missile, the direction of velocity of missile points at the collision point. KKV can intercept the target with lower overload, faster speed via disturbance observer, which is currently estimating and dynamically compensating to target acceleration. Moreover, comparison to the two interception strategies were obtained with interception trajectories, capture zones and velocity range. Another strategy is the sliding mode guidance law based on finite time convergence which aims to steer the line of sight rate close to zero. The results show that the validities of the proposed sliding mode guidance law based on collision course in application for kinetic kill vehicle.