Integral Sliding Mode Control Algorithm Research Articles

An Attitude Adaptive Integral Sliding Mode Control Algorithm with Disturbance Observer for Microsatellites to Track High-Speed Moving Targets

Gaze tracking of high-speed moving targets is a novel application mode for low Earth orbit microsatellites. In this mode, small satellites are equipped with high-resolution, narrow-field-of-view video cameras for stable gaze-tracking imaging of high-speed moving targets. This paper proposes a high-precision attitude adaptive integral sliding mode control method with a feedforward compensation disturbance observer to enhance the capability of a microsatellite attitude control system for gaze tracking of high-speed moving targets. Specifically, first, we present the attitude control system model for microsatellites and the calculation method for the desired attitude of target tracking based on image feedback. Then, an adaptive integral sliding mode attitude control algorithm with a feedforward compensation disturbance observer, which meets the requirements of high-precision tracking control, is designed. The developed algorithm utilizes the disturbance observer to observe the friction torque of the flywheel and compensates for it through feedforward control. It also employs the adaptive integral sliding mode control algorithm to reduce the impact of uncertain disturbances, decrease the steady-state error of the system, and enhance attitude control precision. Simulation experiments demonstrated that the designed disturbance observer can successfully observe the frictional disturbance torque of the flywheel. The attitude Euler angle control precision for high-speed moving target tracking reached 0.03°, and the angular velocity control precision reached 0.005°/s, validating the effectiveness of the proposed approach.

Proposed Feedback-Linearized Integral Sliding Mode Control for an Electro-Hydraulic Servo Material Testing Machine

High-precision tracking of an electro-hydraulic servo material testing machine’s force control system was achieved using a proposed integral sliding mode control method based on feedback linearization to improve the machine’s force control performance and anti-interference ability. First, the electro-hydraulic servo system’s nonlinear mathematical model was established, and its input–output linearization was realized using differential geometry theory. Second, integral sliding mode control was introduced into the controller and the feedback-linearized integral sliding mode controller was designed. The controller’s stability was proven based on the Lyapunov stability principle. Finally, a simulation model of the electro-hydraulic servo material testing machine’s force control system was established using AMESim/Simulink software. The designed controller was simulated and verified, and the control effects of the system’s different amplitudes and frequency signals were analyzed. The results showed that the feedback-linearized integral sliding mode control algorithm could effectively improve the system’s force tracking accuracy and parameter adaptability, yielding better robustness and a better control effect.

Coordinated control of AFS and DYC for electric vehicles with mechanical elastic electric wheels considering the roll effects and uncertain parameters

In order to improve the lateral stability of in-wheel motors electric vehicles (IMEV) equipped with mechanical elastic electric wheels (MEEW) under extreme conditions, this paper proposes an integral sliding mode control (ISMC) algorithm based on the coordination of active front steering (AFS) and direct yaw moment control (DYC) considering the roll effects and the uncertainty of tire cornering stiffness. Firstly, the AFS control algorithm based on adaptive integral terminal sliding mode is proposed, which uses radial-basis-function neural network (RBFNN) to adaptively approximate the integrated nonlinear unknown disturbance. Secondly, considering the roll effects and uncertain cornering stiffness, a mismatched uncertain system for integrated control of AFS and DYC is established. An integral sliding mode control algorithm based on linear matrix inequality (LMI) is designed, and the asymptotic stability of sliding mode dynamics is proved. Further, a constraint optimization algorithm is used to distribute the additional yaw moment. Then, a coordinated control strategy based on the elliptical stable region of the phase plane and the rollover index is designed to activate the integrated controller of AFS and DYC at the right time. Finally, the effectiveness of the control algorithm is verified by high-fidelity CarSim-Matlab simulations. The results show that the proposed controller can effectively and robustly ensure the vehicle lateral stability under extreme conditions.

Robust trajectory tracking control scheme using transformed velocities for asymmetric underactuated marine vehicles

The paper addresses the issue of trajectory tracking control for underactuated underwater vehicles whose model is described by quasi-velocities resulting from the decomposition of the inertia matrix. The control algorithm takes into account unmodeled dynamics and external disturbances. It is shown that such mathematical models can be diagonalized and described by inertial quasi-velocities (IQV). The control scheme consists of a kinematic velocity controller and a dynamic adaptive integral sliding mode control algorithm. The paper extends the concept based on velocity transformation and backstepping methods to systems with a symmetric inertia matrix. A proof of the stability of a closed system in IQV space was carried out. The proposed approach was verified on two 3 DOF models of underwater vehicles with constraints due to the application of thruster force limitations.

Research on inertial reference units prescribed performance integral sliding mode angle control

In this paper, a prescribed performance integral sliding mode control (ISMC) algorithm is proposed to realize high precision and rapid response for an inertial reference unit (IRU). To ensure rapid response, a tracking differentiator (TD) is introduced to arrange a transition process for a desired signal. Tracking error is limited within two prescribed performance function (PPF) bounds to improve transient performance of the IRU. By a prescribed performance error transformation, an error transformation system is established to transform the original constrained system into an equivalent unconstrained one for the IRU. A prescribed performance integral sliding mode controller is designed for the error transformation system to ensure stead-state accuracy. Stability of the prescribed performance ISMC algorithm is proved by a Lyapunov method. Comparative experiments are given to verify effectiveness and robustness of the prescribed performance ISMC algorithm for the IRU.

Indirect neural-based finite-time integral sliding mode control for trajectory tracking guidance of Mars entry vehicle

This article presents an indirect neural-based finite-time integral sliding mode control algorithm for the reference trajectory tracking guidance of Mars entry vehicle under uncertainties. The proposed controller is developed as a combination of finite-time integral sliding mode controller and indirect neural identification. The finite-time integral sliding mode controller is designed by constructing a new type of finite-time integral sliding mode surface to prevent the singularity problem. Moreover, the neural network (NN) is combined with the finite-time integral sliding mode controller to identify the lumped uncertainty and attenuate the chattering phenomenon. Particularly, the concept of indirect neural identification is adopted and only a single adaptive parameter is required to be learned online. In this way, the proposed controller is not only strongly robust against aerodynamic and density uncertainties, but also computationally simple for onboard implementations. Stability argument indicates that the proposed controller can ensure the radial distance tracking error and its time differentiation regulate to the small residual sets around zero in finite time. Lastly, the effectiveness and excellent guidance performance of the proposed control algorithm are demonstrated through simulation studies on a Mars Science Laboratory-type (MSL-type) entry vehicle.

Coordinated control of working implements-vehicle body for terrain adaptation of a robotized hilly tractor

In order to improve driving safety and comfort in hilly terrain, at the same time to ensure the accuracy of sowing, spraying and harvesting, terrain adaptability is needed for hilly tractor. A robotic hilly tractor is designed. The original contribution of this study is the development of two types of terrain adaptive sliding mode control algorithms for attitude adjusting of the vehicle body and the working implement. The terrain-adaptive principle and control constraints of the vehicle body attitude adjusting and the inclination angles following of the working implement to the terrain are introduced. The dynamic model of the attitude adjusting and the terrain following are established. To eliminate destructive additional torque on the transmission system during attitude adjustment, a model reduced integral sliding mode control algorithm combined with feedforward control is proposed, which can ensure the precise synchronization of the left-right swing mechanism under time-varying nonlinear disturbances. A third-order sliding mode control algorithm with differential observation, which can realize the fast and non overshoot tracking of a third-order nonlinear working implement to the terrain change even if only one state variable can be measured. The validity of the above control algorithm is verified by simulation and field tests.

Event-triggered finite-time formation control for second-order leader-following multi-agent systems with nonlinear term time delay

ABSTRACT Event-triggered finite-time formation control is considered for second-order leader-following multi-agent systems with nonlinear term time delay in this study. Collision avoidance radius is designed for a class of second-order nonlinear multiagent systems to avoid collisions between agents. Collision avoidance control is realised by detecting the flight radius. Control cost is economised, and communication volume is reduced by controlling key nodes and designing an event-triggered control strategy. The system can realise formation control in finite time by designing an FTC function. Some sufficient conditions for the formation of the second-order multi-agent system in finite time are obtained by using Lyapunov stability theory and analysis. The integral sliding mode control algorithm and finite-time stability theory are used to enhance the robustness of the system, and the upper bound of finite time is given. At the same time, the ability of the designed event-triggered function to avoid Zeno behaviour is proven. Finally, the feasibility of the results is verified through a numerical simulation.

Preliminary Research on Intelligent Baking Room Dehydration and Drying Technology for Rice Sterile Seeds

The quality of rice seed is very important for rice production. In the process of rice seed production, seed drying is an important link in the whole process of seed quality control, and the problems in mechanical drying are important factors affecting the quality of rice seed. It is easy to encounter rain weather when the sterile seeds are dried by natural air, which seriously affects the seed vigor. High-quality rice seed is an important guarantee to achieve high yield of rice, and seed germination rate is one of the factors directly affecting rice yield. The drying process has the greatest effect on the quality and germination rate of sterile rice seeds. Selecting reasonable drying technology is an important means to ensure the germination rate of sterile rice seeds. In this paper, the dewatering and drying technology of rice sterile line seeds in intelligent baking room was studied. An adaptive integral sliding mode control algorithm based on Smith prediction was proposed for intelligent baking room temperature. The lag in the system was compensated by Smith prediction; the uncertainty of the system model and the complex interference under variable operating conditions were overcome by the robustness of sliding mode control. And the chattering of the sliding mode was eliminated by the adaptive integral sliding mode surface. The seeds of three rice varieties were dried, the drying dehydration rate, seed germination rate, and seed vigor were measured, and the changes of seed moisture and temperature during drying were observed. The results showed that there was little difference in the seed vigor after drying and air dried, which proved that the dryer could be used to dry different kinds of male sterile seeds. Compared with air dried seeds, the germination rate and germination potential of all mechanically dried seeds have little difference, and the overall difference of germination index and vitality index is also small. This study solved the problem that the seeds of male sterile lines could not be dehydrated and dried in time of rainy weather, which is of great significance to improve seed quality and economic benefits.

Adaptive longitudinal control for multivehicle cooperative systems with actuator saturation under road bumps

AbstractIn this article, an adaptive longitudinal control strategy is proposed for a multivehicle cooperative system with actuator saturation. The multivehicle cooperative system is modeled as a longitudinal system. Uncertain disturbances caused by road bumps during vehicle driving are estimated by an adaptive extended state observer based on Silverman canonical transformation and pole placement. An adaptive integral sliding mode control algorithm is designed to accomplish adaptive longitudinal control and handle actuator saturation. With Lyapunov criterion, stability is presented for the multivehicle cooperative system with the adaptive longitudinal control strategy. Simulation results are given to show effectiveness of the adaptive extended state observer and the adaptive integral sliding mode control algorithm.

A new continuous integral sliding mode control algorithm for inverted pendulum and 2-DOF helicopter nonlinear systems: Theory and experiment

This paper introduces a new continuous integral sliding mode control algorithm, where the discontinuous function of the super-twisting control law is replaced with a continuous disturbance observer for the substantial chattering attenuation. In the present integral sliding mode control, the discontinuous function generates chattering that is undesirable for several real-time applications. The proposed control strategy decreases the amplitude of the controller gain compared to the existing integral sliding mode controls, and as a consequence of this, the attenuation of chattering is achieved to a great extent. The efficacy of the proposed control algorithm is validated successfully on the single-input single-output Inverted Pendulum and 2-DOF Helicopter nonlinear coupled multi-input multi-output systems. The simulation and experimental results demonstrate the successful application of the proposed control approach to follow reference inputs and acquire robustness and stabilization of the system in the presence of limited matched perturbations and nonlinearities.

P-Rob Six-Degree-of-Freedom Robot Manipulator Dynamics Modeling and Anti-Disturbance Control

In this paper, the problem of modeling and anti-disturbance control is studied for lightweight personal robotics (P-Robs) with a six-degree-of-freedom robot manipulator to solve the movement instability phenomenon caused by time-varying uncertain disturbances during the movement of the robot manipulator. The detailed dynamical equations of the P-Rob system are solved based on the Lagrange energy equation, and the actual dynamical model of the robot manipulator system is obtained. The disturbance observer is designed to estimate the disturbance effectively, and an integral sliding mode control algorithm is proposed to realize tracking control. Stability analysis of the system is carried out using the Lyapunov function. Finally, experiments are conducted on an actual P-Rob system model, and the experimental results show that the robot manipulator system tracks the desired trajectory effectively, which validates the effectiveness of the proposed control algorithm.

Multivariable finite-time composite control strategy based on immersion and invariance for quadrotor under mismatched disturbances

A novel multivariable finite-time composite integral sliding mode control algorithm with disturbance observer is investigated for a quadrotor unmanned aerial vehicle in the presence of mismatched and matched disturbances. A finite-time disturbance observer based on a multivariable supertwisting algorithm is designed as a stepping stone to estimate and cancel directly the mismatched and matched disturbances simultaneously. A composite adaptive law based on immersion and invariance theory, which introduces supervision factors and dynamic scaling factors, is proposed to compensate for the inaccuracy of modeling and the uncertainty of system parameters. Moreover, a novel integral sliding mode controller with a supertwisting term is designed by combining the composite adaptive law and the disturbance observer. The finite-time tracking of the time-varying trajectory is proven via Lyapunov-based stability analysis. Comparative simulation results illustrate the effectiveness and superiority of the proposed strategy.

Robust trajectory tracking control for an underactuated autonomous underwater vehicle based on bioinspired neurodynamics

This article investigates the three-dimensional trajectory tracking control problem for an underactuated autonomous underwater vehicle in the presence of parameter perturbations and external disturbances. An adaptive robust controller is proposed based on the velocity control strategy and adaptive integral sliding mode control algorithm. First, the desired velocities are developed using coordinate transformation and the backstepping method, which is the necessary velocities for autonomous underwater vehicle to track the time-varying desired trajectory. The bioinspired neurodynamics is used to smooth the desired velocities, which effectively avoids the jump problem of the velocity and simplifies the derivative calculation. Then, the dynamic control laws are designed based on the adaptive integral sliding mode control to drive the underactuated autonomous underwater vehicle to sail at the desired velocities. At the same time, the auxiliary control laws and the adaptive laws are introduced to eliminate the influence of parameter perturbations and external disturbances, respectively. The stability of the control system is guaranteed by the Lyapunov theorem, which shows that the system is asymptotically stable and all tracking errors are asymptotically convergent. At the end, numerical simulations are carried out to demonstrate the effectiveness and robustness of the proposed controller.

Design of permanent magnet synchronous motor speed loop controller based on sliding mode control algorithm

.The control performance of Permanent Magnet Synchronous Motor will be affected by the fluctuation or changes of mechanical parameters when PMSM is applied as driving motor in actual electric vehicle,and external disturbance would influence control robustness.To improve control dynamic quality and robustness of PMSM speed control system, a new second order integral sliding mode control algorithm is introduced into PMSM vector control.The simulation results show that, compared with the traditional PID control,the modified control scheme optimized has better control precision and dynamic response ability and perform better with a stronger robustness facing external disturbance,it can effectively solve the traditional sliding mode variable structure control chattering problems as well.

Design of integral sliding mode control for DC-DC converters

The development and implementation of an integral sliding mode control algorithm for closed loop control of a DC-DC buck converter is presented in this paper. Integral sliding mode controller (ISMC) is formulated to tackle the variable switching frequency problem faced during load and supply variations in conventional sliding mode controlled buck converters. Variable switching frequency is undesirable as it leads to complications while designing filters for the system. ISMC aims to alleviate this problem through appropriate transformation of the sliding mode control lawmaking use of pulse width modulation scheme. The control algorithm is validated through detailed simulation studies in MATLAB/Simulink environment. Comprehensive comparative assessment of the converter control system using ISMC is carried out with conventional sliding mode control (SMC) scheme which reveals the fixed frequency functioning of ISMC under diverse operating conditions.

Adaptive Integral Sliding Mode Stabilization of Nonholonomic Drift-Free Systems

This article presents adaptive integral sliding mode control algorithm for the stabilization of nonholonomic drift-free systems. First the system is transformed, by using input transform, into a special structure containing a nominal part and some unknown terms which are computed adaptively. The transformed system is then stabilized using adaptive integral sliding mode control. The stabilizing controller for the transformed system is constructed that consists of the nominal control plus a compensator control. The compensator control and the adaptive laws are derived on the basis of Lyapunov stability theory. The proposed control algorithm is applied to three different nonholonomic drift-free systems: the unicycle model, the front wheel car model, and the mobile robot with trailer model. The controllability Lie algebra of the unicycle model contains Lie brackets of depth one, the model of a front wheel car contains Lie brackets of depths one and two, and the model of a mobile robot with trailer contains Lie brackets of depths one, two, and three. The effectiveness of the proposed control algorithm is verified through numerical simulations.

Permanent-magnet synchronous motor velocity control based on second-order integral sliding mode control algorithm

In this paper, a novel second-order integral sliding mode control (SOSMC) algorithm is proposed to accomplish velocity control of the permanent-magnet synchronous motor (PMSM) so that the performance can be improved. An integral manifold is utilized to reduce the static error during the sliding mode movement phase to improve the control precision, and a new SOSMC law is achieved by a Lyapunov function approach so the system convergence is guaranteed. The presented method can not only eliminate the system chattering problem successfully but also improve the performance of the PMSM control system. Meanwhile, in order to solve the problem of the windup phenomenon of the PMSM control system, an anti-windup control method is proposed in the PMSM control system. The simulation experimental results are given to indicate that the proposed method is effective and can improve the performance of the PMSM control system such as fast response, high robustness and speed tracking precision, etc.

Applying output feedback integral sliding mode controller to uncertain time-delay systems with mismatched disturbances

For time-delay systems with mismatched disturbances and uncertainties, this paper develops an integral sliding mode control algorithm using output information only to stabilize the systems. An integral sliding surface is comprised of output signals and an auxiliary full-order compensator. The proposed output feedback sliding mode controller can satisfy the reaching and sliding condition and maintain the system on the sliding surface from the initial moment. When two specific algebraic Ricca- ti inequalities have solutions, our method can guarantee the stability of the closed-loop system and sa- tisfy the property of robust disturbance attenuation. Moreover, the design parameters of controller and compensator can be simultaneously determined by solutions to the algebraic Riccati inequalities. Final- ly, two numerical examples illustrate the applicability of the proposed scheme.

Output feedback integral sliding mode controller of time‐delay systems with mismatch disturbances

AbstractFor uncertain time‐delay systems with mismatch disturbances, this paper presented an integral sliding mode control algorithm using output information only. An integral sliding surface is comprised of output signals and an auxiliary full‐order compensator. The designed output feedback sliding mode controller can locally satisfy the reaching and sliding condition and maintain the system on the sliding surface from the initial moment. Since the system is in the sliding mode and two specific algebraic Riccati inequalities are established, the proposed algorithm can guarantee the stability of the closed‐loop system and satisfy the property of disturbance attenuation. Moreover, the design parameters of the controller and compensator can be simultaneously determined by solutions to two algebraic Riccati inequalities. Finally, a numerical example illustrates the applicability of the proposed scheme.Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society