Impact Angle Constraint Dual-Layer Adaptive Guidance Law With Actuator Faults

Abstract

To intercept maneuvering target considering impact angle constraint and actuator faults, a novel three-dimensional (3D) guidance law is proposed in this paper. To guarantee the interception, the multi-variable super-twisting-algorithm-like (STA-like) is adopted in the proposed guidance law, so as to drive the line-of-sight (LOS) angle to the desired value and its rate to zero in finite time in both pitch and azimuth directions. However, it is usually a difficult task for STA-like to select the proper design parameters, and the necessary disturbance gradient for STA-like is also not clearly known, owing to realistic actuator faults and the independence between missile and target. Moreover, the actuator faults in this paper are formulated as disturbances in the control scheme, and the necessary disturbance gradient for STA-like is not clearly known as well. To solve these problems, a multi-variable dual-layer adaptive scheme is employed to adjust the control gains and guarantees its precision. The theoretical analysis and numerical simulation results demonstrate the effectiveness of the proposed guidance law. The combination of STA-like and adaptive theory in the presented guidance law for the first time can guarantee the successful interception and can generate precise and robust control signal simultaneously with impact angle constraint and actuator faults consideration.

Multivariable Adaptive Super-Twisting Guidance Law Based on Barrier Function

“…Theorem 1. In consideration of the three-dimension missile-target engagement system with terminal angle constraint (5), the proposed adaptive multivariable super-twisting guidance law (29) with barrier function gains (25) can drive the sliding surface to converge to a small neighborhood around zero.…”

“…Additionally, super-twisting methods are applied in the area of guidance law design. Reference [29] designed an STA-like guidance law considering actuator faults based on the equivalent control value. References [30,31] designed adaptive STA guidance laws which could be convergent in finite time based on the increasing gains.…”

“…[32] proposed a modified adaptive STA guidance law considering seeker delays. However, these STA controllers have some disadvantages: the methods in [24][25][26]29,32] require the upper bounds of disturbances derivatives to select the filter constants; and the gains of methods in [27,28,30,31] keep increasing throughout the progress, and cannot follow disturbances when they are decreasing, which may lead to large output, or even instability.…”

Measurement Compensation for Time-Delay Seeker and Three-Dimensional Adaptive Guidance Law Design

“…There is a distinct disadvantage in that the gain will not decrease; as a consequence, the controller will not follow the disturbance when it is decreasing. To address this problem, reference [36] utilized an equivalent control strategy, as proposed in [33], and designed a STA-like guidance law with actuator faults constraint. Considering the target maneuvering as system disturbance, the guidance laws based on STA control have a smooth output without obtaining target maneuvering.…”

“…Considering the target maneuvering as system disturbance, the guidance laws based on STA control have a smooth output without obtaining target maneuvering. However, due to the linear error form between the adaptive gain and the disturbance [33,36], the convergence speed of the error is slow and results in slow, even false, adaptive gains.…”