Research On Guidance And Control Technologies For Cost-effective All-strapdown Miniature Missiles

In order to meet the urgent practical needs of hitting low-value,lightly armored targets and effectively reducing the collateral damage of warheads in low-intensity military operations such as local conflicts and anti-terrorism operations,the development of cost-effective all-strapdown miniature missiles is a significant trend for precision-guided weapons.Taking the cost-effective all-strapdown miniature missile as the research object and considering practical problems existing in the all-strapdown guidance scheme,such as the heavy dependence of the guidance law on inertial guidance information,the field-ofview(FOV)constraint of strapdown seeker to ensure target locking,the severe coupling between guidance and control loops,as well as disturbance-prone attitude dynamics characteristics,etc.,the related guidance and control technologies are deeply studied in this thesis.The main contents and achievements of this research are summarized as follows:The tangent-type barrier Lyapunov function(tan-BLF)based look angle constrained guidance law and the logarithmic-type barrier Lyapunov function(log-BLF)based adaptive look angle constrained guidance law are proposed.Aiming at the FOV constraint of strapdown seeker,the component of the missile-target closing velocity perpendicular to the instantaneous missile-target line-of-sight(LOS)is modeled as a constrained system state from the perspective of the guidance system design,thus formulating a nonlinear system control problem.For this nonlinear system control problem with partial states constrained,based on the barrier Lyapunov function(BLF)control method,the tan-BLF based look angle constrained guidance law and the log-BLF based adaptive look angle constrained guidance law are proposed,respectively.The stability of the entire closed-loop system and the boundedness of the constrained state are rigorously proved,thus guaranteeing the FOV constraint not to be violated.The enhanced extended state observer(EESO)based robust acceleration autopilot design method is proposed.This thesis firstly argues that what should be truly observed and compensated for in the disturbance rejection based control(DRBC)may be the “unfavorable disturbance”.A reference model,which describes the expected steady state of the controlled system,is presented to differentiate the “unfavorable disturbance”from all disturbances and uncertainties imposed on the controlled system,and a novel observer named EESO is proposed to estimate this generalized disturbance.On the other hand,this thesis gives a rigorous proof of equivalent input disturbance(EID),which answers a longstanding question of whether the EID exists or not in the DRBC.Introducing the concept of EID further enables the proposed method to handle multiple mismatched disturbances,and the intractable mismatched disturbance compensation gain is greatly reduced to “-1”.In view of the disturbance-prone attitude dynamics characteristics,according to this method,an EESO based robust acceleration autopilot is designed.The closed-loop numerical simulations of the guidance and control systems are carried out.According to the proposed tan-and log-BLF based look angle constrained guidance laws,as well as the EESO based robust acceleration autopilot design method,the guidance and control systems are designed for a longitudinal all-strapdown miniature missile model.Assuming the missile is guided to hit ground stationary,nonmaneuvering moving and maneuvering moving targets,unbiased closed-loop numerical simulation and Monte-Carlo experiment in the presence of uncertainties in atmospheric parameters,body structure parameters and aerodynamics coefficients,as well as gust disturbance are both implemented to test the performance of designed guidance and control systems.A refined integrated guidance and control(IGC)design model with body LOS(BLOS)angle as constrained state and considering actuator saturation is built.Different from IGC models that are commonly used,this novel model first takes both the gravity and varying missile velocity into account,cancels the angle-of-attack information that is used for constructing feedback system in previous studies despite it is unmeasured in practice,and introduces the overloads with respect to the body coordinate system,which can be measured by on-board accelerometer directly and precisely,to replace commonlyused simplified linear aerodynamic force model,so as to accurately model all forces on the missile body except the gravity.Aforementioned refinement makes the IGC model no longer limited to the unpowered flight section where the aerodynamic force of missiles changes smoothly,and will also contribute to improving final hit accuracy of the IGC law designed based on the proposed refined IGC model.The integral-type barrier Lyapunov function(int-BLF)based BLOS angle constrained IGC law and output to input saturation transformation(OIST)based BLOS angle constrained IGC law are proposed.Based on the pure tracking guidance law and parallel approaching guidance law,the proposed two BLOS angle constrained IGC laws effectively address the severe coupling between the guidance and control loops and,are capable of guiding the missile to accurately hit the intended target without acquiring inertial guidance information.In addition,the designs based on the BLF and the OIST technique theoretically guarantee the boundedness of BLOS angle,thus satisfying the FOV constraint within full flight trajectory.Moreover,introducing the Nussbaum function enables the proposed two BLOS angle constrained IGC laws to avoid the occurrence of actuator saturation problem effectively,and smooth and filter the control input command at the same time,thus eliminating the high frequency chattering caused by the sign function used in the IGC design.This thesis systematically investigates the guidance and control technologies of costeffective all-strapdown miniature missiles.The results of research provide certain theoretical and technical support and engineering technology reserve for the all-strapdown miniature missile guidance and control system design,and also possesses great reference value and research significance for the design method of missile look angle constrained guidance law,robust attitude control law and IGC law.