Robust Attitude Tracking Control Research Articles

Robust Attitude Tracking Control Based on Adaptive Dynamic Programming for Flexible Dumbbell-Shaped Spacecraft

Robust Attitude Tracking Control Based on Adaptive Dynamic Programming for Flexible Dumbbell-Shaped Spacecraft

Attitude maneuver planning and robust tracking control for flexible satellite

Abstract In this paper, we investigate the attitude manoeuver planning and tracking control of the flexible satellite equipped with a coilable mast. Due to its flexible beamlike structure, the coilable mast experiences bending and torsional modal vibrations in multi-direction. The complex nonlinear coupling and other external disturbances significantly impact the achievement of high-precision attitude control. To overcome these challenges, a robust attitude tracking controller is proposed for easy implementation by the Attitude Determination and Control System (ADCS). The controller consists of a disturbance compensator, feedforward controller and output feedback controller. The compensator, based on a Nonlinear Disturbance Observer (NDO), effectively compensates for the cluster disturbances caused by vibrations, environmental factors and parameter perturbations. The feedforward controller tracks the desired path in the nominal satellite model. Furthermore, the output feedback controller enables large-angle manoeuver control of the satellite and evaluates the suppression effect of the controlled output on the observation error of cluster disturbances used the ${L_2}$ -gain. Simulation results demonstrate that the proposed controller successfully achieves high-precision attitude tracking control during large-angle manoeuvering.

Robust attitude tracking control for a variable‐pitch quadrotor with uncertainties

SummaryVariable‐pitch quadrotors have demonstrated their capability to enhance control performance and overcome limitations compared to conventional fixed‐pitch quadrotors, while still facing challenges such as nonlinearity, couplings, uncertainties and so on. This article aims to address the robust attitude control problem of variable‐pitch quadrotors afflicted with parametric uncertainties and unpredictable external disturbances. Initially, a practical actuator allocation strategy for the motor‐propeller is proposed, followed by the development of a nonlinear robust attitude tracking controller capable of addressing all uncertainties. The effectiveness of the proposed controller in ensuring exponential stability of the closed‐loop system, thereby driving the attitude tracking error to a small range within a finite time, has been substantiated. To evaluate the control performance, a hardware‐in‐the‐loop testbed is constructed to conduct real‐time experiments. The experimental results from attitude control case, comparative case, and position control case demonstrate that the designed motor‐propeller allocation method and robust controller are effective in achieving a fast response and excellent control performance.

Three‐dimensional path following control of underactuated autonomous underwater vehicles with nonzero roll dynamics: A novel line‐of‐sight‐guided approach

AbstractMost existing path following control approaches for underactuated Autonomous underwater vehicles (AUVs) assumed that the roll angle can be passively stabilized at zero, and simplified the problem to the 5‐degree‐of‐freedom model. However, in practice, the roll motion suffers from undesirable oscillations induced by environmental disturbances, unbalanced propeller torque, etc. To preserve the stability of the system under nonzero roll dynamics, this paper proposes a novel line‐of‐sight‐ (LOS) guided path following control approach. Firstly, the spatial path following error dynamics model is derived to comprehensively reveal the negative effect of roll dynamics. Secondly, an improved LOS guidance law is designed to compensate for the nonzero roll angle. A salient feature is that the proposed guidance law can be applied to the underwater vehicle no matter it is underactuated in the roll motion or not. Thirdly, by assigning the guidance angles to the desired attitude angles, a robust attitude tracking controller is developed, in which the adaptive estimation technique is employed to handle the lumped uncertainties. The tanh‐based saturation function is incorporated such that the resultant control signals are inherently bounded. The closed‐loop path following and attitude tracking errors are proved to be globally asymptotically stable at the origin. Comparative simulation results are provided to substantiate the effectiveness and superiority of the proposed method.

Adaptive Robust Tracking Control for Near Space Vehicles with Multi-Source Disturbances and Input–Output Constraints

In this paper, considering the simultaneous influence of multi-source disturbances, system modeling uncertainties and input–output constraints, an adaptive robust attitude tracking control scheme is proposed for near space vehicles (NSVs) which is expressed as a stochastic nonlinear system. A multi-dimensional Taylor polynomial network (MTPN) is utilized to handle the system uncertainties, and the nonlinear disturbance observer (NDO) based on MTPN is designed to estimate the external disturbances. Furthermore, by constructing the auxiliary system to tackle the input saturation and introducing the Tan-type barrier Lyapunov function (TBLF) to solve the output constraint, the constrained control strategy can be obtained. Combining with backstepping control (BC) technique and stochastic control method, an adaptive robust stochastic control scheme is developed based on NDO, MTPN, and auxiliary system, and the closed-loop system stability in the sense of probability is analyzed based on stochastic Lyapunov stability theory. Finally, numerical simulations further demonstrate the feasibility of the proposed tracking control scheme.

Signum-Function-Based Multi-Input Multi-Output Adaptive Homogeneous Finite-Time Control for a Rigid-Body Attitude Tracking

This study is devoted to investigating the robust adaptive finite-time attitude tracking control problem for a rigid body subject to unknown uncertainties. Considering about the nonlinear attitude dynamics for a rigid body, a homogeneous sliding variable is designed by employing the signum-function technique. For the presented homogeneous sliding variable, a real sliding manifold, on which the singularity problem is avoided, could be achieved. Subsequently, a novel signum-function-based MIMO adaptive homogeneous finite-time control (SMAHFTC) algorithm is proposed. Finite-time convergence of the tracking errors to a region around the origin is rigorously proved through the Lyapunov approach. The control gains will not be overestimated, which implies that minimal control gains will be obtained by the adaptation law. Moreover, the controls’ signals are continuous for the SMAHFTC law. Then, by means of the proposed design method, an attitude tracking controller is designed for a rigid body described by the modified Rodrigues parameters’ (MRPs) representation. A comparison simulation is carried out to show the effectiveness and superiority of the proposed method.

Robust attitude tracking control of spacecraft under unified actuator dynamics

This paper investigates the attitude tracking control of spacecraft under unified actuator dynamics. The inertia uncertainties, external disturbances, and input saturation are also considered. A novel robust attitude tracking control scheme is proposed by incorporating a disturbance observer and an auxiliary dynamic system into the command filtered backstepping control design. The command filtered backstepping control can avoid the ‘explosion of complexity’ problem inherently existing in the traditional backstepping control. The disturbance observer is designed to estimate the mismatched compound disturbance induced by inertia uncertainties and external disturbances. The auxiliary dynamic system is conducted to tackle the effect of input saturation. The uniform ultimate boundedness of the overall closed-loop system is rigorously proved. The proposed controller can guarantee the attitude tracking errors converge to the arbitrary small neighbourhood of zero even subject to actuator dynamics. Numerical simulations and comparisons illustrate the effectiveness and advantages of the proposed control scheme.

Control robusto de la actitud para el seguimiento de trayectoria de un VANT

This paper proposes a robust attitude tracking control applied to Vertical Take-off and Landing Micro Aerial Vehicles (VANT) based on Active Disturbance Rejection Control (ADRC) approach. The proposed technique groups the endogenous and exogenous disturbances into a total disturbance, which is estimated online via extended state observer (ESO). Once the disturbance is determined, a quaternion-based controller is proposed, which compensates and relieves the disturbance actively. The control law is bounded; consequently, it takes into account the maximum capabilities of the actuators. The stability proof of the closed-loop (observer and control) is guaranteed in the ISS sense. The simulation results allow validating the theoretical features.

Disturbance Observer-Based Attitude Control for Spacecraft With Input MRS

This paper considers the problem of attitude tracking control for uncertain rigid spacecraft subject to control input magnitude and rate saturation (MRS). First, a smooth input MRS model is proposed. Then, a robust attitude tracking control scheme is designed based on the backstepping and finite-time disturbance observer techniques. Finally, the effectiveness of the control scheme derived here is illustrated by numerical simulations.

Robust H∞ compensator with constraints for attitude manoeuvres of a quadrotor subject to unknown stochastic input delays

ABSTRACTThis paper addresses the robust compensator design problem for the attitude tracking of an indoor micro quadrotor subject to unknown stochastic input delays and input constraints. The attitude dynamics of the micro quadrotor is modelled as a nonlinear system with linear parametric uncertainties, unknown stochastic input delays, input constraints and disturbances. Based on the uncertain model and the Hanlanay's inequality, both robust attitude tracking controller and suboptimal robust controller with constraints are developed by constructing an appropriate Lyapunov–Krasvokii function and presenting standard linear matrix inequalities. The suggested controllers not only achieve the exponential stabilisation of attitude of the quadrotor but also guarantee the given performance. Finally, both numerical simulation and experimental results are provided to illustrate the effectiveness and merits of the proposed methods.

Two‐Layer Terminal Sliding Mode Attitude Control of Satellites Equipped with Reaction Wheels

AbstractThis paper addresses the global stability and robust attitude tracking problem of a near polar orbit satellite subject to unknown disturbances and uncertainties. It is assumed that the satellite is fully actuated by a set of reaction wheels (RW) as control actuators because of their relative simplicity, versatility and high accuracy. The terminal sliding mode control (TSMC) approach is utilized in a two‐level architecture to achieve control objectives. In the lower layer a detumbling‐like controller is designed which guarantees the finite‐time detumbling and tracking of the desired angular velocities and based on this result a robust attitude tracking controller is designed in the upper layer to achieve 3‐axis attitude tracking in the presence of unknown disturbances and bounded uncertainties. Robust stability and tracking properties of designed controllers are proved using the Lyapunov theory. Finally, a set of numerical simulation results are provided to illustrate the effectiveness and performance of the proposed control method.

Robust Attitude Tracking Control for Spacecraft with Quantized Torques

The problem of spacecraft attitude tracking with limited communication to actuators is addressed in this paper. A hysteresis quantizer is employed to quantize the signal of control torque. The hysteresis quantizer requires low communication rate and avoids control chattering. An indirect (nonregressor-based) robust adaptive control scheme is proposed to deal with the effects of quantization error and external disturbances. The proposed control scheme together with the quantizer ensures global boundedness of all the signals in the closed-loop system and enables the attitude tracking error to converge toward a residual.

A New Robust Controller Formulation for the Full–State Feedback Position Tracking of a Small–Scaled Unmanned Model Helicopter

This work focuses on the robust attitude tracking control problem for a small– scaled unmanned helicopter where the actual system inputs, namely the elevator servo input, the aileron servo input and the rudder servo input, are used in the controller formulation. The design process is divided into two parts. Initially the problem is transformed into a second order system with an uncertain non–symmetric input gain matrix by utilizing some reasonable simplifications for the rotor model under the hovering flight conditions. Then a novel robust control methodology is utilized via a matrix decomposition method. The stability of the overall system is ensured by Lyapunov type analysis where asymptotic position tracking is ensured. Numerical simulation results are presented to demonstrate the efficiency of the proposed method.

Robust output feedback attitude tracking control for rigid-flexible coupling spacecraft

This paper investigates the robust attitude tracking control problem for a rigid-flexible coupling spacecraft. First, the dynamic model for a rigid-flexible coupling spacecraft is established based on the first-order approximation method to fully reveal the coupling effect between rigid movement and flexible displacement when the spacecraft is in rapid maneuver. In the condition that flexible vibration measurements are not available, an robust output feedback controller which is independent of model is presented using Lyapunov method with considering state-independent disturbances. To resolve the chattering problem caused by the discontinuous sign function, a modified continuous output feedback controller is proposed by introducing functions with continuous property. Rigorous proof is achieved showing that the proposed control law ensures asymptotic stability and guarantees the attitude of a rigid-flexible spacecraft to track a time-varying reference attitude based on angle and angular velocity measurements only. Finally, simulations are carried out to verify the simplicity and effectiveness of the proposed control scheme.

Robust adaptive spacecraft attitude tracking control based on similar skew-symmetric structure

This paper addresses robust adaptive attitude tracking control for spacecrafts with unknown inertia parameters and bounded external disturbances. The similar skew-symmetric structure is chosen as the desired structure for the closed loop system when there exist no uncertainties. Based on this idea, a backstepping scheme is proposed to design the controller, and adaptive compensation and robust compensation are introduced to deal with the uncertainty of the inertia parameters and the external disturbances respectively. Theoretical analysis shows that fast response and high tracking precision can both be obtained by regulating the related parameters in the proposed controller. Simulation results are provided to demonstrate the effectiveness of the proposed attitude tracking control algorithm.

Nonlinear Robust Attitude Tracking Control of a Table-Mount Experimental Helicopter Using Output Feedback

This paper proposes a robust attitude tracking controller for a table-mounted experimental helicopter that has three rotational degrees-of-freedom and only equips angular position sensors. The proposed controller can achieve output-feedback attitude tracking of the pitch and elevation channels of the helicopter. The experimental platform is subjected to model uncertainties, coupling effects, and equips with an independent active disturbance system, which have effectively examined the robustness of proposed controller. The control law includes a second-order auxiliary system to generate filtered error signals, and a discontinuous uncertainty and disturbance estimation (UDE) term to compensate the model uncertainties and external disturbances. A Lyapunov-based stability analysis shows the semiglobal asymptotic tracking ability of the proposed controller. The experimental results further demonstrate that the proposed method can achieve equivalent dynamic and static performance compared to other high-performance state-feedback methods, and even when the initial position is away from design point, it also gives more consistent responses than other linear methods.

Robust attitude tracking control of spacecraft under control input magnitude and rate saturations

SummaryThis paper investigates the problem of attitude tracking control of spacecraft subject to control input magnitude and rate saturations. The smooth hyperbolic tangent function is used to model the magnitude and rate saturations. As the system is non‐affine in the control input, an augmented plant is presented to facilitate the development of the control law. The backstepping technique, robust control and adaptive control approaches are applied to design the control law. The stability of the closed‐loop system is guaranteed by the Lyapunov method. Numerical simulations are presented to demonstrate the performance of the proposed controller. Copyright © 2015 John Wiley & Sons, Ltd.

Decentralized robust attitude tracking control for spacecraft networks under unknown inertia matrices

This article investigates the quaternion-based attitude tracking problem for spacecraft networks, where the interaction topology among spacecraft switches periodically and inertia matrices are totally unknown. The tracking error dynamics is modeled. A class of robust attitude coordination controller without introducing the information about external disturbances is proposed. Using the Lyapunov method and graph theory, it is proved that the controller can guarantee a group of spacecraft to track the time-varying reference attitude. Further, the tracking error can be adjusted by designers to satisfy different requirements of control accuracy. Finally, simulation results are presented to illustrate that the designed control law is successful in achieving high tracking performance, even in the presence of unknown external disturbance torque, unknown inertia matrices and switching interaction topology among spacecraft.

High accuracy robust attitude tracking control application on quadrotor UAV with the prescribed performance

In this paper, a high accuracy attitude tracking control is presented for a quadrotor unmanned aerial vehicle (UAV) under the model uncertainties and external unpredictable disturbances by using a robust feedback control method. First, the cascade attitude dynamics of a quadrotor UAV is derived with the lumped disturbances. Then, a backstepping adaptive modified robust integral of the sign of the error (RISE) control is designed to improve the robustness of the control system against the disturbances. For arriving high accuracy tracking under the disturbances, a prescribed performance control algorithm is employed in combination to hold the transient state performance where the convergence rate is faster than the prescribed value, and the maximum overshoot is less than the prescribed value. The stability analysis is carried out to prove that the presented controller could guarantee that the closed-loop system is asymptotically stable, and the tracking feedback errors can converge to an arbitrarily small value near zero. The superior performance of the proposed control method is illustrated in simulations against the nonlinear lumped disturbances, and the benefits of the proposed robust controller is corroborated by comparing with the existed controller.

Nonlinear disturbance observer based robust attitude tracking controller for quadrotor UAVs

This paper presents a robust attitude tracking controller for quadrotors based on the nonlinear disturbance observer, which has been developed recently. The structural condition on the input gain matrix, which is not easy to check, is removed by factorizing it into two parts and modifying the disturbance observer structure. A constructive design procedure is provided and it is shown that the proposed controller recovers the performance of the nominal closed-loop system in the whole time horizon under parameter uncertainties and disturbance torques. The results are validated through simulations and compared with the feedback linearization design.