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This paper presents an Adaptive Variable Structure Control (AVSC) methodology to autonomously control an UAV platform known as the Vectored Thrust Aerial Vehicle (VTAV). The proposed control algorithm eliminates chattering present in Sliding Mode Control (SMC), and improves the settling time of the VTAV system by driving the error states in a parabolic trajectory towards the origin of error space...
This paper introduces a class of fixed-time stable dynamical systems with settling time as a explicit parameter, namely the inverse the gain. Those systems are defined as predefined-timed stable dynamical systems. Continuous and discontinuous are cases are presented. A detailed Lyapunov characterization of this class of systems is also shown. Finally, the application to the design of a class of first...
Sliding mode control (SMC) is one of the few controller design methodologies that can be applied to highly nonlinear and uncertain systems. In most mechanical applications, a smoothed version of SMC that we call “sliding control” is employed to keep the system trajectories close to but not necessarily on a stable differential/difference manifold. In this paper, we propose an extension to the sliding...
Most of the controllers design are based on a process model. Generally, the processes are nonlinear, of high order and thus the number of tuning parameters for the controller are in proportion to the model order. Mobile robot models are nonlinear and complex, and the use of traditional procedures to design the SMC would result in a really extensive and probably inefficient expression. For that reason,...
This paper proposes a control algorithm to solve multiple quadrotor formation problem in a leader-follower configuration. A combination of sliding mode control (SMC) and linear quadratic regulator (LQR) are used for trajectory tracking control of a single robot. Position control, which acts as the outer loop is controlled by LQR for providing the reference attitude angles for the inner loop. SMC used...
In this paper two types of sliding mode control (SMC): normal sliding mode control (normal-SMC) and Quasi sliding mode control (Quasi-SMC) are used in controlling single-link rotational base flexible manipulator for three different payloads. The dynamic equations of the system are done by using Lumped parameter method. Quasi-SMC is used for chattering elimination which is present in the case of normal-SMC...
This paper presents a comparative study of two control approaches; fuzzy proportional derivative control (PD) and sliding mode control (SMC) for a two degree of freedom (2-DOF) robot manipulator. It presents the implementation of both model based and model free based control. SimMechanics is used for modelling of the robot which requires a little knowledge regarding the dynamics of the system. A robust...
A comparative analysis on chattering based on Sliding Mode Controller (SMC) techniques for a single link flexible manipulator is presented in this paper. The proposed controller techniques include i) normal-SMC ii) Quasi-SMC iii) Asymptotic-SMC. These controllers are used in controlling the tip position as well as the tip deflection of the system. Lyapunov stability theory is used to achieve the stability...
Robot-assisted therapy has become an important technology used to restore and reinforce the motor functions of the patients with neuromuscular disorders. In this paper, we proposed an upper-limb exoskeleton intended to assist the rehabilitation training of shoulder, elbow and wrist. The proposed therapeutic exoskeleton has an anthropomorphic structure able to match the upper-limb anatomy and enable...
A new family of continuous higher order sliding mode algorithm (CHOSMA) for arbitrary relative degree system via continuous control signal is proposed. The convergence conditions for the third order-CHOSMA algorithm is formulated based on homogeneous Lyapunov function. The formula for algorithm of arbitrary order is also suggested. The simulation results are confirmed the efficiency of the proposed...
In this paper we have applied two types of control on two coupled water tanks, where the dynamic model is nonlinear system. The first control is the sliding mode with linear surface, the advantages of this type of control is the discontinuity behavior which can be applied to variable structure systems (VSS) and its good robustness against the injected disturbances, and/or the noise, and finally unaffected...
This paper presents a nonlinear control based on sliding mode control (SMC) for the position and the attitude tracking control of a small coaxial-rotor UAV subjected to uncertainties and aerodynamic disturbances. The dynamical motion equations are obtained through the Newton-Euler formalism. Firstly, the dynamical model is divided into a fully actuated subsystem and an underactuated subsystem. Secondly,...
In this paper, trajectory tracking for nonholonomic mobile robots is addressed. Two strategies are proposed: the first is based on Lyapunov stability theory, while the second adopts sliding mode control. The main difference between the two proposed strategies is that the time required for the error to converge towards zero is not a constraint in the first strategy while it is limited in the second...
In this paper, we discuss event-triggering scheme with sliding mode control where sensors are distributed over network. Here, a decentralized event-triggering mechanism is proposed where event is observed at each sensor nodes with local information for possible triggering and control update is done whenever a centralized event is triggered. In order to achieve this, the states are sampled at any one...
In this paper, a hexapod robot that consists of its body and six legs is considered. The leg mechanism is a 1-UP&2-UPS (U-universal joint, P-prismatic joint and S-spherical joint) parallel mechanism with three degree-of-freedoms (DOFs). A comparative investigation of tracking control methods in the hexapod robot with parallel legs is presented. The methods include standard PID control, position-velocity...
The paper is devoted to the design of robust control algorithms for mechanical systems. Mechanical systems have a special form of mathematical models which allows application of the modified method of aggregation of the state variables. In the paper control algorithms for robust control design are derived and their use is shown in the example.
In this paper, the problem of motion control for small autonomous underwater vehicle (SAUV) is addressed. Firstly, for the position detection problem of SAUV underwater sailing, the dead reckoning method based on Doppler Velocity Log (DVL), compass and depth gauge is proposed. Then, aiming at the problem of controller designing for SAUV trajectory tracking, the segmented control strategy combining...
In this paper, the problem of designing sliding mode controls (SMCs) for uncertain time-delay systems is considered. We extend the linear matrix inequality (LMI) approach of Choi [5] to include such systems. Based on the LMI-based method of Choi [5], we get sufficient conditions for the existence of linear sliding surfaces in terms of LMIs, which define convex solution sets, and we show that linear...
In this paper a digital variable structure control algorithm, directly derived from a continuous one, previously presented by the authors, is considered. The proposed algorithm is able to perform the second order sliding mode control of a large class of uncertain second order nonlinear SISO systems. The discretization effects of the control law on the system behaviour are analyzed, and the sufficient...
In this note, the tracking trajectory problem for a wheeled mobile base has been solved using the robot dynamical model. The proposed solution is based on sliding mode control. The asymptotic vanishing of the tracking errors has been theoretically proved, and simulation results have been reported, showing the effectiveness of the proposed control law.
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