Adaptive Dynamic Sliding Mode Control Research Articles

Adaptive Dynamic Boundary Sliding Mode Control for Robotic Manipulators under Varying Disturbances

This paper introduces an Adaptive Dynamic Bounded Sliding Mode Control (ADBSMC) method that incorporates a disturbance observer to enhance the response characteristics of the robot manipulator while eliminating the reliance on a priori knowledge. The proposed method utilizes nonlinear sliding mode manifolds and fast-terminal-type convergence laws to address errors and parameter uncertainties inherent in the nonlinear system models. The adaptive law is designed to cover all boundary conditions based on the model’s state. It can dynamically determine upper and lower bounds without requiring prior knowledge. Consequently, the ADBSMC control method amalgamates the benefits of adaptive law and fast terminal sliding mode, leading to significant enhancements in control performance compared with traditional sliding mode control (SMC), exhibiting robustness against uncertain disturbances. To mitigate external disturbances, a system-adapted disturbance observer is devised, facilitating real-time monitoring and compensation for system disturbances. The stability of ADBSMC is demonstrated through the Lyapunov method. Simulation and experimental results validate the effectiveness and superiority of the ADBSMC control scheme, showcasing its potential for practical applications.

Observer-based adaptive dynamic sliding mode control for automatic clutch position tracking

The automatic clutch’s precise and stable position tracking is critical in automated manual transmission, significantly influencing vehicle performance. Clutch position control is challenging due to directly unmeasurable clutch output position, nonlinear characteristics, parameter uncertainties, and external disturbance of the automatic clutch system. This paper proposes an observer-based adaptive dynamic sliding mode control strategy to overcome these obstacles to the clutch position tracking process. The extended state observer (ESO) introduced in the designed strategy handles total disturbance, including nonlinearities and uncertainties for feedback control and total compensation. A sigmoid tracking differentiator arranges the transient process and smooth approach signal for the reference input and its differential signal. An adaptive dynamic sliding mode controller acts as the primary feedback control to realize fast and precise position tracking of the automatic clutch system based on the signal from ESO. Simulation and hardware-in-loop (HIL) experimental tests verify the effectiveness and advantage of the proposed control strategy for the clutch position tracking performance in the face of parameter perturbation and external disturbance, for example, the root mean square value of static tracking error of the designed strategy is 14.9% and 24.7% lower than that of ESO-based sliding mode control and robust sliding mode control strategy in the HIL test, respectively.

Finite-Time Adaptive Extended State Observer-Based Dynamic Sliding Mode Control for Hybrid Robots

This brief investigates the finite-time adaptive extended state observer (ESO) based dynamic sliding mode control (SMC) for the hybrid robot subject to uncertain problem, e.g., modeling error, joint friction, external disturbance and so on. A barrier function-based adaptive law is defined to adjust the switching gain of SMC system with unknown upper bound of the disturbance. Such an adaptive law-based control method ensures the finite-time convergence of the sliding variable to an adjustable vicinity of zero and realizes chattering reduction of SMC. Then, for estimating and compensating system uncertainties, the time-varying gain ESO (TESO) is designed without the condition of the disturbance change rate tending to zero. A system error-based adaptive law is designed to adjust the observer bandwidth gain, which can reduce the peaking value. Such a TESO reduces the burden of SMC and further weakens the chattering of SMC, so as to improve the control system robustness. The finite-time Lyapunov stability of the sliding variable and the boundness of the TESO error have been proved theoretically. The practical effectiveness is illustrated in simulations and experiments with the prototype of hybrid robot.

Extended dissipative analysis and taxiing control of fuzzy model based aircraft-on-ground systems via sliding mode approach

This paper is concerned with the sliding mode control for aircraft-on-ground during deceleration phases. Due to the strong coupling and nonlinearity of aircraft, a standard model has been formulated from the aircraft-on-ground dynamics. This standard model is then represented in a Takagi-Sugeno fuzzy system with input saturation due to the limited steering angle of the front wheel and rudder angle as well as the braking force. Furthermore, a (Q,S,R)−γ-dissipative analysis strategy is applied to attenuate the effect of the wind disturbance. Then, an integral-type fuzzy sliding surface is developed and sufficient conditions are obtained for the sliding mode dynamics to be asymptotically stable with extended dissipation. The adaptive dynamic sliding mode control law is designed, which has the ability to compensate the effects of input saturation and extra disturbance, and ensure the reachability of the sliding surface in finite time. Finally, the simulation results are presented to illustrate that the sliding mode control strategy proposed in this paper can effectively maintain the aircraft taxiing route in different runway environments.

Learning Control for Flexible Manipulators with Varying Loads: A Composite Method with Robust Adaptive Dynamic Programming and Robust Sliding Mode Control

This paper focuses on the learning-based motion control for flexible manipulators with varying loads via the singularly perturbed technique. Considering the two-timescale feature of the flexible manipulator, system dynamics are decomposed into fast and slow subsystems, and corresponding sub-controllers are designed with robust adaptive dynamic programming (RADP) and robust sliding mode control (RSMC) methods, respectively. In the proposed composite control framework, an RADP-based sub-controller is developed to realize the trajectory tracking and alleviate the parametric uncertainty utilizing rotating angles in the slow timescale, while an RSMC sub-controller is introduced to improve the vibration suppression in the fast timescale. Finally, the stability of the closed-loop system is guaranteed, and simulations are carried out to show the effectiveness of the proposed control algorithm.

Feedback Linearization Adaptive Dynamic Sliding Mode Control of Linear Synchronous Motor for CNC Machine Tools

Feedback Linearization Adaptive Dynamic Sliding Mode Control of Linear Synchronous Motor for CNC Machine Tools

Modelling, Simulation and Dynamic Sliding Mode Control of a MEMS Gyroscope.

An adaptive dynamic sliding mode control via a backstepping approach for a microelectro mechanical system (MEMS) vibratory z-axis gyroscope is presented in this paper. The time derivative of the control input of the dynamic sliding mode controller (DSMC) is treated as a new control variable for the augmented system which is composed of the original system and the integrator. This DSMC can transfer discontinuous terms to the first-order derivative of the control input, and effectively reduce the chattering. An adaptive dynamic sliding mode controller with the method of backstepping is derived to real-time estimate the angular velocity and the damping and stiffness coefficients and asymptotical stability of the designed systems can be guaranteed. Simulation examples are investigated to demonstrate the satisfactory performance of the proposed adaptive backstepping sliding mode control.

PID sliding surface-based adaptive dynamic second-order fault-tolerant sliding mode control design and experimental application to an electromechanical system

In this paper, an adaptive dynamic PID sliding surface-based second-order fault-tolerant sliding mode controller for speed control of an electromechanical system is proposed. The paper aims to show how to utilise the robust properties of second-order adaptive dynamic sliding mode control on the problem of structural damage fault. Structural damage fault is apparently studied less than faults of actuator and sensor. Because of this reason, this study focuses on the structural damage fault. In order to solve the chattering which is the main problem of first-order/ traditional SMC, second-order controller is designed. The Lyapunov theorem is used for affirming the design and stability of the closed-loop system. Experimental results show that the control system with the proposed controller is easily implemented. Also, the proposed fault-tolerant controller, concerning parametric uncertainties and disturbances, acquire suitable tracking performance and shows more robustness than the traditional SMC.

Integral vector field control for three-dimensional path following of autonomous underwater vehicle

A new control method for autonomous underwater vehicle (AUV) is developed to achieve three-dimensional (3D) path following under ocean current disturbances when AUV lacks lateral and vertical driving forces. To make the control system more convenient for practical application and reduce the energy consumption of AUV, the controller is designed with relative velocities. To avoid the singularity problem of curve path following, the Serret–Frenet frame is introduced as virtual target and the error model is defined. The adaptive law of the virtual target and an integral vector field (IVF) guidance law are designed in the kinematic controller. The back-stepping method and adaptive dynamical sliding mode control (BADSMC) technology are applied in the design of dynamic controller. The Lyapunov theory and nonlinear cascade system theory are applied to prove the closed-loop stability. Finally, the performances of the IVF + BADSMC and ILOS + PID algorithm are compared through simulation. Simulation results demonstrate that the proposed controller can realize the path following of AUV under disturbances of ocean current and can improve the following quality.

Extended state observer-based adaptive dynamic sliding mode control for power level of nuclear power plant

It is well known that nuclear energy is a clean, safe, and reliable energy resource. Nuclear power plant is one of the prominent applications of nuclear energy. In this paper, aiming at improving the control performance for power level of nuclear power plant, an extended state observer-based adaptive dynamic sliding mode control (ESO-ADSMC) scheme is proposed. The mathematical model of nuclear reactor is firstly constructed based on point-reactor kinetics equations. Then, an extended state observer is designed to estimate both unmeasured states and output disturbances in real time, and the asymptotic convergence of the observer error state space is analyzed according to Routh-Hurwitz and Lyapunov stability theory. Subsequently, an adaptive dynamic sliding mode control approach is proposed for power level control of nuclear power plants in the presence of output disturbances, which is a combination of sliding mode control and backstepping control to enhance disturbance rejection ability. In addition, the chattering phenomenon is eliminated due to the discontinuous sign function contained in the first derivative of actual control input. Finally, simulation studies are carried out to demonstrate the feasibility and effectiveness of the proposed control strategy compared with backstepping control method in terms of the accuracy and rapidity of the response of power level, and robustness against output disturbances.

Path Planning under Constraints and Path Following Control of Autonomous Underwater Vehicle with Dynamical Uncertainties and Wave Disturbances

The path planning and following control problems of autonomous underwater vehicle (AUV) in three-dimension (3D) are studied in this paper. In order to realize obstacle avoidance and path optimization, a path planning method based on particle swarm optimization (PSO) and cubic spline interpolation is developed. The curvature of the path obtained by this method is continuous, which can not only avoid obstacles but also meet the constraint of AUV’s minimum radius of rotation. In the design of kinematics controller, an optimal guidance scheme based on model predictive control (MPC) is proposed, which takes into account the wave disturbances. Adaptive dynamical sliding mode control (ADSMC) technology is used to design dynamic controller, which can effectively overcome the influence of model uncertainties. In order to ensure the stability of the system, the stability condition of MPC is designed, and the stability of the closed-loop system is analyzed by applying cascade system theory. The control strategy proposed in this paper is compared with the line-of-sight (LOS) guidance through simulation experiment. The simulation results demonstrate that the proposed control strategy can not only improve the quality of path following, but also reduce the disturbance of waves, and thus is more conducive to energy saving.

Design of an adaptive dynamic sliding mode control approach for robotic systems via uncertainty estimators with exponential convergence rate

In this work, an adaptive dynamic sliding mode control approach is proposed for robotic systems via uncertainty estimators with exponential convergence rate. The uncertainties are estimated using various uncertainty estimators such as the Fourier series expansion, Legendre polynomials and adaptive fuzzy systems. Also, for each uncertainty estimator, the approximation error is compensated. The adaptation laws are derived using a stability analysis. Moreover, the asymptotic convergence of the tracking error and the boundedness of all closed-loop signals are guaranteed. The novelty of this paper is proposing a positive exponential function for the convergence rate of the adaptation rules to prevent from initial high voltages originated from large initial tracking errors. Another novelty of this paper is presenting a robust control term for the truncation error that improves the accuracy of the control system. Analysis of simulations reveals the effectiveness of the proposed method in terms of fast disturbance rejection and negligible tracking error.

Adaptive Dynamic Sliding Mode Control Laws for Attitude Stabilization of Flexible Spacecraft

In this paper, an adaptive dynamic sliding mode control technique is adopted to stabilize the attitude of flexible spacecraft with disturbance. The mathematical model of flexible spacecraft is constructed by the modified Rodrigues parameters. The adaptive control technique is applied to guarantee stabilization of flexible spacecraft with disturbance. By introducing a dynamic switching function, the chattering caused by sign function of the traditional sliding mode control law can be eliminated. Finally, by comparing with the adaptive control law proposed in [12], a numerical example is employed to illustrate the effectiveness of the designed control law.

Robust tracking control for vehicle electronic throttle using adaptive dynamic sliding mode and extended state observer

• The mathematical modelling of automotive engine electronic throttle (EET) system is obtained by considering the nominal model and parameter uncertainty component and all the system uncertainties are detailedly analyzed, then a modified extended state observer (ESO) is adopted to estimate the lumped uncertainty online. • An adaptive dynamic sliding mode (ADSM) feedback control scheme with ESO techniques is designed to achieve a robust closed-loop tracking performance. By adopting the ESO and designing the dynamic secondary sliding surface (DSSS), the chattering phenomenon of the conventional sliding mode can be significantly alleviated. • The additional dynamics introduced in the sliding mode can improve the system stability. A detailed theoretical stability analysis for the whole closed-loop EET control system is presented by innovatively combining the observer dynamics with the feedback control system. • The real-time experimental results from the DSP-based EET experimental platform are given with performance comparisons with other controllers, and both the excellent performance and robustness of the proposed control are achieved. • The robust adaptive dynamic sliding mode control scheme for EET systems will provide the automotive engineers with a good candidate of robust EET controller in practical applications. The proposed control technique can also be applied to other automotive systems for achieving excellent control performance. This article proposes an extended state observer (ESO)-based robust adaptive dynamic sliding mode (ADSM) tracking control for an automobile engine electronic throttle (EET) system. The newly developed control scheme exhibits the following three attractive characteristics. First, a modified ESO is adopted to estimate the lumped uncertainty online. Second, an ADSM feedback control is then designed to achieve a robust closed-loop tracking performance. Third, the switching gain is adaptively updated by the adaptive law to eliminate the need of the uncertainty information. The stability proof combining the observer with the feedback control is presented in detail. High tracking precision and robustness of the proposed control are verified by extensive experimental results with comparison of existing adaptive sliding mode control and conventional robust controllers.

Control of Z-Axis MEMS Gyroscope Using Adaptive Fractional Order Dynamic Sliding Mode Approach

This paper proposes a states feedback control method for Z-axis MEMS gyroscopes using fractional calculus and adaptive dynamic sliding mode control method. A new sliding mode control method is proposed to achieve trajectory tracking by adding a fractional order term in the conventional sliding manifold. The new proposed sliding surface contains integer order terms as well as fractional order terms and thus can provide an extra degree of freedom. Besides, in the presence of unknown system parameters, some adaptive laws containing the new designed sliding manifold are proposed to online tune controller parameters. All adaptive laws are derived in the stability framework and the stability of the control system is also guaranteed according to the Lyapunov stability theory and. Simulations results on a Z-axis vibrating gyroscope are provided to illustrate the effectiveness of the control method.

Adaptive dynamic sliding mode control for space manipulator with external disturbance

ABSTRACTIn this paper, a novel adaptive dynamic sliding mode control(ADSMC) methodology is developed for space manipulator control systems with external disturbance. The proposed ADSMC approach can make the systems stable and accurately track the desired signals in the presence of external disturbances. Firstly, the simplified dynamic model of the manipulator is introduced. Then, the proposed adaptive dynamic sliding mode(ADSM) controller is given, which is proved to be able to guarantee high tracking accuracy via effectively estimating the disturbance boundary. Finally, experimental results show that the dynamic sliding mode controller proposed in this paper can not only track the desired trajectory, but also present strong robustness for external disturbance, meanwhile effectively reduce the chattering phenomenon generated by switching between different sliding mode surfaces.

Research on the sliding mode control for underactuated surface vessels via parameter estimation

This brief proposes an adaptive sliding mode control law for an underactuated vessel via parameter estimation to follow a desired path. An adaptive continuous PI sliding mode scheme is devoted to enhancing the robustness of the control system and reducing the system oscillation in presence of unknown plant parameters and environmental disturbances. To address model uncertainties and unknown environmental disturbances, an adaptive parameters estimation and an upper bound estimation scheme are incorporated with the control scheme. In addition, a novel virtual control approach based on backstepping and adaptive dynamical sliding mode control is designed to relax the assumption of passive boundedness in sway motion. Under this kind of consideration, a certain nonlinear scheme is proposed to guarantee sway velocity uniformly ultimately bounded by Lyapunov direct method. Finally, numerical simulation results are given to demonstrate the effectiveness of the proposed method.

Speed tracking control of pneumatic motor servo systems using observation-based adaptive dynamic sliding-mode control

This study aims to develop an adaptive high-precision control system for controlling the speed of a vane-type air motor (VAM) pneumatic servo system. In practice, the rotor speed of a VAM depends on the input mass air flow, which can be controlled by the effective orifice area (EOA) of an electronic throttle valve (ETV). As the control variable of a second-order pneumatic system is the integral of the EOA, an observation-based adaptive dynamic sliding-mode control (ADSMC) system is proposed to derive the differential of the control variable, namely, the EOA control signal. In the ADSMC system, a proportional–integral–derivative fuzzy neural network (PIDFNN) observer is used to achieve an ideal dynamic sliding-mode control (DSMC), and a supervisor compensator is designed to eliminate the approximation error. As a result, the ADSMC incorporates the robustness of a DSMC and the online learning ability of a PIDFNN. To ensure the convergence of the tracking error, a Lyapunov-based analytical method is employed to obtain the adaptive algorithms required to tune the control parameters of the online ADSMC system. Finally, our experimental results demonstrate the precision and robustness of the ADSMC system for highly nonlinear and time-varying VAM pneumatic servo systems.

Control of the nuclear steam generators using adaptive dynamic sliding mode method based on the nonlinear model

The water level control problem of steam generators has been a main cause of unexpected shutdowns of nuclear power plants which must be considered for plant safety and availability. The control problem is challenging, especially at low power levels due to shrink and swell phenomena and flow measurement errors. Moreover, the dynamics of steam generator vary as the power level changes. Therefore, it is necessary to improve the water level control system of SG. In this paper, at the first a nonlinear model based on the fundamental conservation equations for mass, energy and momentum is presented for the nuclear steam generator which is validated with other computer programs and experimental results and then, an adaptive dynamic sliding mode control method is applied for the level control problem of U-tube steam generators based on the presented nonlinear model. The proposed method exhibits the desired dynamic properties during the entire output tracking process independent of perturbations. Simulation results are presented to demonstrate the effectiveness of the proposed controller in terms of performance, robustness and stability. Simulation results confirm the improvement in transient response obtained by using the proposed controller.

Dynamical sliding mode control for the trajectory tracking of underactuated unmanned underwater vehicles

This paper proposes a novel adaptive dynamical sliding mode control based methodology to design control algorithms for the trajectory tracking of underactuated unmanned underwater vehicles (UUVs). The main advantage of the approach is that the combination of backstepping and sliding mode control enhances the robustness of an UUV in the presence of systematical uncertainty and environmental disturbances. The position and attitude dynamical equations of an underactuated UUV are first represented and analyzed using coordinate transformation with the aid of backstepping technique. Subsequently, the output feedback problem is tackled by employing adaptive sliding mode control to estimate the systematical uncertain states required by the stable velocity tracking controller. The final controlled system can be proved to be globally asymptotically stable based on Lyapunov stability theory. Simulations performed on an underactuated UUV demonstrate the effectiveness of the proposed method.