Research On Guidance And Attitude Control Of High Lifting Reentry Vehicle

In this paper,a high lifting hypersonic gliding reentry vehicle is taken as the research object,and the paper mainly focus on the guidance and the attitude control of the vehicle.There are some difficulties of the guidance and attitude control designing as reentry process faces a complex environment and some hard constraints.In view of these problems,this paper mainly does the following work.First of all,this paper studies the predictor-corrector algorithm guidance method.Predictor-corrector algorithm is not affected by the initial value.However,it is difficult to deal with the hard constraints.According to the three-dimensional equations of motion of the gliding vehicle,this paper divides the reentry movement into the initial re-entry and gliding segments.The initial segment has little effect on the trajectory due to the low atmospheric density.As the atmospheric density rises,the so-called quasi-equilibrium glide condition will be satisfied.In the gliding phase,the predictor-corrector is formed by longitudinal and lateral guidance.Longitudinal guidance law makes the vehicle meet the downrange and the hard path constraints and the lateral guidance determines when to perform bank-angle reversals.Secondly,a trajectory tracking law is studied.Based on the idea of model predictive control,this paper constructs an optimal control problem in the moving horizon window,and alter it into a two-point boundary value problem by using the optimal control principle.Then the Gauss pseudospectral method is implement to the two-point boundary value problem.The proposed method can eliminate the initial error.Furthermore,when failures occur such as the rudder surface stuck,the aircraft's aerodynamic model will change,and the nominal reference trajectory will no longer be valid.Based on the above trajectory tracking method,this paper changes the trajectory planning problem into an optimization problem.The Gaussian pseudospectral method is used to solve the optimization problem,and the reference trajectory is obtained.Finally,this paper studies a passive fault-tolerant control method for controlling the attitude of reentry vehicles.The method is based on the idea of backstepping-control,and the attitude control system is divided into two steps to design.The first step is to design the desired angular velocity as the virtual control of the kinematics.The next is to tracking the desired angular velocity.The fault-tolerant control method does not need to know the information of the moment of inertia.