Research On Guidance Law Design With Multiple Constraints And Simulation

It is an important factor that the guidance law which is the key technology to guidancesystem affects the overall performance of the missile weapons. For the traditional guidedweapons, the main function of the guidance system is to generate the appropriate controlinstructions to make the miss distance to approach zero. However, with the rapid developmentof the missiles and targets, miss distance is not the only tactical and technical indicators. Forexample, in order to achieve the better combat effect, it is not only to get a minimum missdistance, but also to hope to hit the target under a certain terminal rendezvous angle whenattacking airports, command centers, large vessels and other important military value of thetarget; Again, when the missile use the direct collision to attack target, it requires to meetconstraints of the terminal rendezvous angle, attack angle, overload, engine working time, etc.Above of all, Considering the control system dynamics, this paper designs a multipleconstraints guidance law based on variable structure control theory which meets miss distance,terminal rendezvous angle. the performance of new guidance law has been verified by digitalsimulation in the end. The main contents of this paper include following sections:Firstly, the mathematical model of terminal guidance system should be constructed. Thecoordinate system and the conversion relationship between the coordinate system matrix areintroduced; then the missile and target motion model are built including the missile center ofmass dynamics and kinematics model and the target center of mass motion model. Relativemotion of parameters is raised, such as the angle of sight and line of sight angular rate. Whatwe do is to lay the groundwork for later study and simulation.Secondly, the miss distance and rendezvous angle constraint are defined.Terminalrendezvous angle constraint is converted to the line of sight angle constraints. The paper usesvariable structure control theory to select the summation of the terminal line of sight angleand sight angular rate as the sliding surface, apply adaptive reaching law, design guidance lawin the vertical plane and lateral plane respectively which satisfies miss distance,terminalrendezvous angle constrained.Typically, missile guidance and control systems are designed separately. In the guidancelaw design process, the missile control system dynamic characteristics are not consideredwhile using the dynamic control loop compensation to weaken the impact of the controlsystem. The paper which considers the dynamic characteristics of the control system is basedon the idea of guidance and control systems integration by analyzing the relative movement between missile and target, and then the dynamic characteristics of the control system isassumed to be first-order and second-order inertial delay part. The guidance law is designed toconsider the first-order and the second-order control system dynamics constraints, and meetthe constraints about the miss distance, terminal rendezvous angle.Finally，digital simulation analysis shows that the design of the guidance law has a goodguidance effect and can also meet the requirements of the above constraints in response tomobile targets.