scholarly journals A Lyapunov-Based Optimal Integral Finite-Time Tracking Control Approach for Asymmetric Nonholonomic Robotic Systems

Symmetry ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2367
Author(s):  
Khalid A. Alattas ◽  
Saleh Mobayen ◽  
Wudhichai Assawinchaichote ◽  
Jihad H. Asad ◽  
Jan Awrejcewicz ◽  
...  
Keyword(s):  
Optimal Control ◽  
Equilibrium Point ◽  
Sliding Mode ◽  
Design Procedure ◽  
Robotic Systems ◽  
Control Input ◽  
Control Lyapunov Function ◽  
Terminal Sliding Mode ◽  
Control Approach ◽  
Precise Control

This study suggests a control Lyapunov-based optimal integral terminal sliding mode control (ITSMC) technique for tracker design of asymmetric nonholonomic robotic systems in the existence of external disturbances. The design procedure is based on the control Lyapunov function (CLF) approach. Hence, the output tracking problem is solved by combining the ITSMC with optimal control. The CLF synthesizes a nonlinear optimal control input for the nominal system. Once the control system’s states lie far away from the operating point, it is activated to drive them toward the equilibrium point optimally. However, on the condition that the system perturbations are the main factor, the ITSMC would be designed to take over in the vicinity of the equilibrium point. Accordingly, the control goals, such as robustness and precise control, are warranted in the perturbed system. The usefulness of the suggested method is demonstrated with a wheeled mobile robot via a simulation study.

scholarly journals Adaptive Fast Non-Singular Terminal Sliding Mode Path Following Control for an Underactuated Unmanned Surface Vehicle with Uncertainties and Unknown Disturbances

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7454
Author(s):  
Yunsheng Fan ◽  
Bowen Liu ◽  
Guofeng Wang ◽  
Dongdong Mu
Keyword(s):  
Actuator Saturation ◽  
Sliding Mode ◽  
Path Following ◽  
Design Parameters ◽  
Real Time Control ◽  
Sideslip Angle ◽  
Terminal Sliding Mode ◽  
Unmanned Surface Vehicle ◽  
Control Approach ◽  
Unknown Disturbances

This paper focuses on an issue involving robust adaptive path following for the uncertain underactuated unmanned surface vehicle with time-varying large sideslips angle and actuator saturation. An improved line-of-sight guidance law based on a reduced-order extended state observer is proposed to address the large sideslip angle that occurs in practical navigation. Next, the finite-time disturbances observer is designed by considering the perturbations parameter of the model and the unknown disturbances of the external environment as the lumped disturbances. Then, an adaptive term is introduced into Fast Non-singular Terminal Sliding Mode Control to design the path following controllers. Finally, considering the saturation of actuator, an auxiliary dynamic system is introduced. By selecting the appropriate design parameters, all the signals of the whole path following a closed-loop system can be ultimately bounded. Real-time control of path following can be achieved by transferring data from shipborne sensors such as GPS, combined inertial guidance and anemoclinograph to the Fast Non-singular Terminal Sliding Mode controller. Two examples as comparisons were carried out to demonstrate the validity of the proposed control approach.

A Nonlinear Optimal Control Approach for the Vertical Take-off and Landing Aircraft

2021 ◽  
pp. 2150012
Author(s):  
G. Rigatos
Keyword(s):  
Optimal Control ◽  
Control Method ◽  
Nonlinear Optimal Control ◽  
The Body ◽  
Algebraic Riccati Equation ◽  
Control Input ◽  
Time Step ◽  
Control Approach ◽  
Vtol Aircraft ◽  
Optimal Control Approach

The paper proposes a nonlinear optimal control approach for the model of the vertical take-off and landing (VTOL) aircraft. This aerial drone receives as control input a directed thrust, as well as forces acting on its wing tips. The latter forces are not perpendicular to the body axis of the drone but are tilted by a small angle. The dynamic model of the VTOL undergoes approximate linearization with the use of Taylor series expansion around a temporary operating point which is recomputed at each iteration of the control method. For the approximately linearized model, an H-infinity feedback controller is designed. The linearization procedure relies on the computation of the Jacobian matrices of the state-space model of the VTOL aircraft. The proposed control method stands for the solution of the optimal control problem for the nonlinear and multivariable dynamics of the aerial drone, under model uncertainties and external perturbations. For the computation of the controller’s feedback gains, an algebraic Riccati equation is solved at each time-step of the control method. The new nonlinear optimal control approach achieves fast and accurate tracking for all state variables of the VTOL aircraft, under moderate variations of the control inputs. The stability properties of the control scheme are proven through Lyapunov analysis.

Smooth second-order nonsingular terminal sliding mode control for reusable launch vehicles

2014 ◽  
Vol 7 (1) ◽  
pp. 95-110 ◽  
Author(s):  
Shaobo Ni ◽  
Jiayuan Shan
Keyword(s):  
Finite Time ◽  
Sliding Mode ◽  
Tracking Error ◽  
Second Order ◽  
Convergence Time ◽  
Control Input ◽  
Terminal Sliding Mode ◽  
Content Type ◽  
Nonsingular Terminal Sliding Mode ◽  
Attitude Tracking

Purpose – The purpose of this paper is to present a sliding mode attitude controller for reusable launch vehicle (RLV) which is nonlinear, coupling, and includes uncertain parameters and external disturbances. Design/methodology/approach – A smooth second-order nonsingular terminal sliding mode (NTSM) controller is proposed for RLV in reentry phase. First, a NTSM manifold is proposed for finite-time convergence. Then a smooth second sliding mode controller is designed to establish the sliding mode. An observer is utilized to estimate the lumped disturbance and the estimation result is used for feedforward compensation in the controller. Findings – It is mathematically proved that the proposed sliding mode technique makes the attitude tracking errors converge to zero in finite time and the convergence time is estimated. Simulations are made for RLV through the assumption that aerodynamic parameters and atmospheric density are perturbed. Simulation results demonstrate that the proposed control strategy is effective, leading to promising performance and robustness. Originality/value – By the proposed controller, the second-order sliding mode is established. The attitude tracking error converges to zero in a finite time. Meanwhile, the chattering is alleviated and a smooth control input is obtained.

scholarly journals Adaptive Fuzzy Integral Terminal Sliding Mode Control of a Nonholonomic Wheeled Mobile Robot

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Shuying Peng ◽  
Wuxi Shi
Keyword(s):  
Mobile Robot ◽  
Sliding Mode ◽  
Kinematic Model ◽  
Small Neighborhood ◽  
Wheeled Mobile Robot ◽  
Fuzzy Integral ◽  
Control Input ◽  
Parameter Uncertainties ◽  
Terminal Sliding Mode ◽  
Adaptive Fuzzy

In this paper, the trajectory tracking problem is investigated for a nonholonomic wheeled mobile robot with parameter uncertainties and external disturbances. In this strategy, combining the kinematic model with the dynamic model, the actuator voltage is employed as the control input, and the uncertainties are approximated by a fuzzy logic system. An auxiliary velocity controller is integrated with an adaptive fuzzy integral terminal sliding mode controller, and a robust controller is employed to compensate for the lumped errors. It is proved that all the signals in the closed system are bounded and the auxiliary velocity tracking errors can converge to a small neighborhood of the origin in finite time. As a result, the tracking position errors converge asymptotically to zeros with faster response than other existing controllers. Simulation results demonstrate the effectiveness of the proposed strategy.

scholarly journals Optimal Control Problem of Treatment for Obesity in a Closed Population

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
D. Aldila ◽  
N. Rarasati ◽  
N. Nuraini ◽  
E. Soewono
Keyword(s):  
Optimal Control ◽  
Equilibrium Point ◽  
Treatment Program ◽  
Transition Process ◽  
Human Interaction ◽  
Intervention Programs ◽  
Obese People ◽  
Control Approach ◽  
Overweight People ◽  
Disease Free

Variety of intervention programs for controlling the obesity epidemic has been done worldwide. However, it is still not yet available a scientific tool to measure the effectiveness of those programs. This is due to the difficulty in parameterizing the human interaction and transition process of obesity. A dynamical model for simulating the interaction between healthy people, overweight people, and obese people in a randomly mixed population is discussed in here. Two scenarios of intervention programs were implemented in the model, dietary program for overweight people with healthy life campaign and treatment program for obese people. Assuming all control rates are constant, disease free equilibrium point, endemic equilibrium point, and basic reproductive ratio (ℛ0) as the epidemic indicator were shown analytically. We find that the disease free equilibrium point is locally asymptotical stable if and only ifℛ0<1. From sensitivity analysis ofℛ0, we obtain that larger rate of dietary program and treatment program will reduceℛ0significantly. With control rates are continuous in time, an optimal control approach was applied into the model to find the best way to minimize the number of overweight and obese people. Some numerical analysis and simulations for optimal control of the intervention were shown to support the analytical results.

Chatter alleviation for a class of second-order under-actuated mechanical systems with matched and mismatched disturbances

2016 ◽  
Vol 23 (3) ◽  
pp. 458-468
Author(s):  
Jinjin Shi ◽  
Jinxiang Wang ◽  
Fangfa Fu
Keyword(s):  
Sliding Mode ◽  
Mechanical Systems ◽  
Design Procedure ◽  
Second Order ◽  
Control Input ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Sliding Surfaces ◽  
Low Pass ◽  
Mismatched Disturbances

The chattering phenomenon and a system with both matched and mismatched disturbances are the major difficulties in sliding mode control design. This paper presents an effective design procedure to alleviate these two difficulties for a class of second-order under-actuated mechanical systems. In the proposed design, new hierarchical sliding surfaces are designed and a modified disturbance observer is utilized to estimate the lumped disturbance which is a linear combination of the matched and mismatched disturbances. The chatter in control input is filtered out by an integrator, which acts as a low-pass filter. The asymptotic stabilities of the entire sliding surfaces are guaranteed. A design study considering lateral control of a vehicle with matched and mismatched disturbances demonstrates the effectiveness of the proposed design.

Adaptive non-singular terminal sliding mode controller: new design for full control of the quadrotor with external disturbances

2016 ◽  
Vol 39 (3) ◽  
pp. 371-383 ◽  
Author(s):  
Alireza Modirrousta ◽  
Mahdi Khodabandeh
Keyword(s):  
Position Control ◽  
Sliding Mode ◽  
Control Input ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Nonlinear Disturbance Observer ◽  
Tuning Method ◽  
Regular Control ◽  
Control Scheme ◽  
Sliding Mode Controllers

This paper proposes two different adaptive robust sliding mode controllers for attitude, altitude and position control of a quadrotor. Firstly, it proposes a backstepping non-singular terminal sliding mode control with an adaptive algorithm that is applied to the quadrotor for free chattering, finite time convergence and robust aims. In this control scheme instead of regular control input, the derivative of the control input is achieved from a non-singular terminal second-layer sliding surface. An adaptive tuning method is utilized to deal with the external disturbances whose upper bounds are not required to be known in advance in the inner loop. Secondly, a nonlinear disturbance observer based on the integral sliding mode with adaptive gains is proposed for position control, which is known as the outer loop. Stability and robustness of the proposed controller are proved by using the classical Lyapunov criterion. The simulation results demonstrate the validation of the proposed control scheme.

scholarly journals Profile-Tracking-Based Adaptive Guidance Law against Maneuvering Targets

2019 ◽  
Vol 2019 ◽  
pp. 1-17
Author(s):  
Jingshuai Huang ◽  
Hongbo Zhang ◽  
Guojian Tang ◽  
Weimin Bao
Keyword(s):  
Convergence Rate ◽  
Sliding Mode ◽  
Tracking Error ◽  
Small Neighborhood ◽  
Terminal Sliding Mode ◽  
Control Approach ◽  
Maneuvering Target ◽  
Guidance Law ◽  
Adaptive Guidance ◽  
The One

For the terminal guidance problem of a missile intercepting a maneuvering target, a profile-tracking-based adaptive guidance law is proposed with inherent continuity in this paper. To flexibly and quantitatively control the convergence rate of the line-of-sight rate, a standard tracking profile is designed where the convergence rate is analytically given. Then, a nonsingular fast terminal sliding-mode control approach is used to track the profile. By estimating the square of the upper bound of target maneuver, an adaptive term is constructed to compensate the maneuver. Therefore, no information of target acceleration is required in the derived law. Stability analysis shows that the tracking error can converge to a small neighborhood of zero in finite time. Furthermore, a guidance-command-conversion scheme is presented to convert the law into the one appropriate for endoatmospheric interceptions. Simulation results indicate that the proposed law is effective and outperforms existing guidance laws.

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