Extended state observer-based finite-time guidance laws on account of thruster dynamics

2019 ◽  
Vol 233 (12) ◽  
pp. 4583-4597 ◽  
Author(s):  
Meijun Duan ◽  
Di Zhou ◽  
Dalin Cheng
Keyword(s):  
Finite Time ◽  
Sliding Mode ◽  
Angular Rate ◽  
State Observer ◽  
Extended State Observer ◽  
Line Of Sight ◽  
Switching Frequency ◽  
Extended State ◽  
Guidance Law ◽  
Guidance Laws

Guidance laws are designed for a near space interceptor with line-of-sight angle as input and on–off type thrust as output. The dynamics of thruster is viewed as a first-order lag with on–off working style and is integrated with the target–interceptor engagement dynamics to design bang-bang type sliding mode guidance laws. An extended state observer is designed to estimate the line-of-sight angular rate and the acceleration of target with the line-of-sight angle as a measurement. It is rigorously proved that the states of guidance system converge to a neighborhood of sliding mode in finite time and the line-of-sight angular rate converges to a neighborhood of the origin along the sliding mode in finite time under the designed guidance laws. Furthermore, in order to reduce the switching frequency of thruster, a sliding mode guidance law with hysteresis-band according to the sufficient condition for finite time convergence is proposed. Then, it is integrated with the bang-bang type sliding mode guidance law to yield a composite guidance law. Simulation results show that the extended state observer can effectively estimate the line-of-sight angular rate and the target acceleration, and the proposed sliding mode guidance laws have better performance than typical proportional guidance law.

scholarly journals Extended state observer-based integral line-of-sight guidance law for path following of underactuated unmanned surface vehicles with uncertainties and ocean currents

2021 ◽  
Vol 18 (3) ◽  
pp. 172988142110110
Author(s):  
Mingcong Li ◽  
Chen Guo ◽  
Haomiao Yu
Keyword(s):  
Sliding Mode ◽  
Path Following ◽  
State Observer ◽  
Extended State Observer ◽  
Ocean Currents ◽  
Line Of Sight ◽  
Extended State ◽  
Integral Sliding Mode ◽  
Unmanned Surface Vehicles ◽  
Guidance Law

This article focuses on the problem of path following for underactuated unmanned surface vehicles (USVs) considering model uncertainties and time-varying ocean currents. An extended state observer (ESO)-based integral line-of-sight (ILOS) with an integral sliding mode adaptive fuzzy control scheme is proposed as the main control framework. First, a novel ESO is employed to estimate the surge and sway velocities based on the kinetic model, which are difficult to measure directly. Then, the adaptive ILOS guidance law is proposed, in which the integral vector is incorporated into the adaptive method to estimate the current velocities. Meanwhile, an improved fuzzy algorithm is introduced to optimize the look-ahead distance. Second, the controller is extended to deal with the USV yaw and surge velocity signal tracking using the integral sliding mode technique. The uncertainties of the USV are approximated via the adaptive fuzzy method, and an auxiliary dynamic system is presented to solve the problem of actuator saturation. Then, it is proved that all of the error signals in the closed-loop control system are uniformly ultimately bounded. Finally, a comparative simulation substantiates the availability and superiority of the proposed method for ESO-based ILOS path following of USV.

Impact angle control based on integral sliding mode manifold and extended state observer

2018 ◽  
Vol 233 (6) ◽  
pp. 2131-2140
Author(s):  
Xiaojian Zhang ◽  
Mingyong Liu ◽  
Yang Li ◽  
Feihu Zhang
Keyword(s):  
Sliding Mode ◽  
Impact Angle ◽  
State Observer ◽  
Extended State Observer ◽  
Line Of Sight ◽  
Extended State ◽  
Integral Sliding Mode ◽  
Guidance Law ◽  
Switched Nonlinear System ◽  
The Impact

This paper discusses the issue of impact angle control over guidance in scenarios of an interceptor against the maneuvering targets. Inspired by switched nonlinear system, an integral sliding mode manifold is first developed. Then, the impact angle control over guidance is derived by using the integral sliding mode manifold with finite time control. To obtain precise guidance effect, the second-order of extended state observer is proposed in the case of unknown target acceleration. Finally, composited impact angle control over guidance based on extended state observer is developed. The stability analysis of the proposed guidance law is demonstrated by using Lyapunov function, and theoretical proof that the line-of-sight angle and line-of-sight angular rate can converge to the desired value in finite steps, respectively. Numerical simulation results are illustrated to validate the performance of the proposed guidance law.

A finite-time-convergent composite guidance law with strong fault-tolerant performance

2018 ◽  
Vol 233 (9) ◽  
pp. 3120-3130 ◽  
Author(s):  
Feng Chen ◽  
Guangjun He ◽  
Qifang He
Keyword(s):  
Finite Time ◽  
Fault Tolerant ◽  
Sliding Mode ◽  
Angular Rate ◽  
Gain Coefficient ◽  
High Gain ◽  
Line Of Sight ◽  
Practical Implementation ◽  
Integral Sliding Mode ◽  
Guidance Law

To improve the performance of tracking and intercepting the low-altitude target, a nonlinear integral sliding mode guidance law is designed firstly, which can guarantee that the line-of-sight angle converges to a desired tracking angle and the line-of-sight angular rate converges to zero in finite time. Meanwhile, to solve the chattering problem caused by the high gain coefficient of the sign function in the guidance law, a sliding mode disturbance observer is designed to estimate the maneuvering acceleration of the target. Moreover, a composite nonlinear integral sliding mode guidance law is designed by introducing the estimated value of the acceleration, which can weaken the chattering phenomenon effectively. Finally, considering the magnitude loss fault of the guidance command that may occur in the practical implementation, a composite guidance law with strong fault-tolerant performance is designed by introducing a fault compensation command, which can effectively improve the reliability of the system.

scholarly journals Extended-State-Observer-Based Terminal Sliding Mode Tracking Control for Synchronous Fly-Around with Space Tumbling Target

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Zhijun Chen ◽  
Yong Zhao ◽  
Yuzhu Bai ◽  
Dechao Ran ◽  
Liang He
Keyword(s):  
Finite Time ◽  
Sliding Mode ◽  
Coupling Effect ◽  
External Disturbance ◽  
Fast Response ◽  
State Observer ◽  
Extended State Observer ◽  
Extended State ◽  
Terminal Sliding Mode ◽  
Tumbling Target

This paper presents a robust controller with an extended state observer to solve the Synchronous Fly-Around problem of a chaser spacecraft approaching a tumbling target in the presence of unknown uncertainty and bounded external disturbance. The rotational motion and time-varying docking trajectory of tumbling target are given in advance and referred as the desired tracking objective. Based on dual quaternion framework, a six-degree-of-freedom coupled relative motion between two spacecrafts is modeled, in which the coupling effect, model uncertainties, and external disturbances are considered. More specially, a novel nonsingular terminal sliding mode is designed to ensure the convergence to the desired trajectory in finite time. Based on the second-order sliding mode, an extended state observer is employed to the controller to compensate the closed-loop system. By theoretical analysis, it is proved that the modified extended-state-observer-based controller guarantees the finite-time stabilization. Numerical simulations are taken to show the effectiveness and superiority of the proposed control scheme. Finally, Synchronous Fly-Around maneuvers can be accomplished with fast response and high accuracy.

Application of Super Twisting Guidance Law Based on Extended State Observer

2013 ◽  
Vol 433-435 ◽  
pp. 1009-1014 ◽  
Author(s):  
Yang Chong ◽  
Ke Zhang
Keyword(s):  
Sliding Mode ◽  
External Disturbance ◽  
State Observer ◽  
Extended State Observer ◽  
Extended State ◽  
Maneuvering Target ◽  
Guidance Law ◽  
Target Acceleration ◽  
Twisting Algorithm ◽  
Miss Distance

In order to intercept high maneuvering target, a super twisting guidance law based on extended state observer (ESO) is proposed. The target acceleration can be defined as external disturbance which can be estimated in ESO and compensated in super twisting guidance law. The super twisting algorithm can effectively decrease the undesired charting which exists in normal sliding mode control. The simulation results which are verified via computer show that this guidance law has strong robustness, target acceleration can be estimated and compensated, and has good miss distance.

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