Research On Sliding Mode Guidance Law For Intercepting Maneuvering Targets

Modern warfare modes are undergoing major changes.The performance of highly mobile targets continues to improve,and higher requirements are placed on the accuracy of missile guidance.It is particularly important to design a guidance law that can intercept maneuvering targets with high precision and robustness.In addition,to complete the damage target,the missile is usually required to intercept the target at the desired angle of attack.Therefore,this paper takes the interception of highly maneuverable targets with a single missile terminal guidance stage as the background.Aiming at the problem of the inaccurate acquisition of target maneuvering information,the main research method is sliding mode control.The main contents are as follows:After the missile interferes with the rotating target,the equation of motion in a two-dimensional plane is defined in the coordinate system.Use the relative distance of the projectile and the angle of sight to describe the relative motion relationship.At the same time,the problem of limiting the angle of attack has arisen out of mathematics.Based on analysis and assumptions,a guidance model considering the angle of attack constraint is established.The traditional sliding mode guidance law only guarantees asymptotic convergence.However,in most practical guidance applications,it is important to converge to the desired angle of attack within a limited time.These finite-time convergence guidance laws have singularities and the defects of treating unknown target acceleration as zero.In this paper,a non-singular terminal sliding mode control scheme is used to design the sliding surface to avoid the singularity of the end of the guidance.On this basis,an extended state observer is constructed to estimate the acceleration of the maneuvering target to improve the tracking performance of the desired cut-off angle.The simulation comparison verifies that the designed guidance law can intercept the target at the desired attack angle for different target maneuvers,and has strong anti-disturbance ability and high guidance accuracy.Consider the angle of attack in the process of intercepting a maneuvering target,and treat the target maneuvering information as unknown interference and an integral sliding mode control guidance law considering the observer is designed.First,design the linear integral sliding mode guidance law.To further improve the convergence characteristics of the induction system,a nonlinear integral sliding mode induction law has been proposed,which guarantees that the line-of-sight angular velocity converges to near zero in finite time and in line-of-sight.The angle is tracked to the desired line-of-sight angle in a finite amount of time.However,in order to ensure that the guidance system has good performance when dealing with the target acceleration,the switching gains of linear and nonlinear integral sliding mode guidance laws need to be selected to be greater than the target acceleration.It can cause chatter.A nonlinear advanced distortion observer is used to estimate the target acceleration.The predicted acceleration is used to cover the actual target acceleration.On this basis,a nonlinear law of continuous shear mode based on a nonlinear observer with extended distortion is proposed.After all,the model suggests that the proposed manual law could have a significant impact on missile targets.A non-singular fast terminal sliding mode guidance law with attack constraints is considered.The guidance law adopts double power approaching law and negative exponential factor attractor,which has a faster speed when approaching the sliding surface.For maneuvering targets,a finite-time observer is designed,through which the unknown acceleration of the target can be estimated,and it is helpful to compensate for the movement.Compared with other non-singular guidance laws,the sliding mode guidance law designed in this section performs well in all aspects.Using matlab for numerical simulation,the missile can still accurately strike the target even when the target is in the most complex maneuver.