Flexible-joint Robots

دسترسی آزاد مقاله

1 - Computer-based Regressor-free Adaptive Control versus Direct Adaptive Fuzzy Control of the Robotic System
Mahmood Nadali Abolghasem Nadali Maryam Nadali

A comprehensive comparison between regressor-free control and direct adaptive fuzzy control of flexible-joint robots is addressed in this paper. In the proposed regressor-free controller, two critical practical situations are considered: the fact that robot actuators ha چکیده کامل

A comprehensive comparison between regressor-free control and direct adaptive fuzzy control of flexible-joint robots is addressed in this paper. In the proposed regressor-free controller, two critical practical situations are considered: the fact that robot actuators have limited voltages, and limitation on the number of measurement devices. However, in the article "decentralized direct adaptive fuzzy control for flexible-joint robots," these limitations have been neglected. It should be noted that a few solutions for the voltage-bounded robust tracking control of flexible joint robots have been proposed. In this paper; we contribute to this subject by presenting a new form of voltage-based controllers. The closed-loop control system stability is proved, and uniformly boundedness of the joint position errors is guaranteed. As a second contribution of this paper, we present a robust adaptive control scheme without the need for computation of the regressor matrix with the same result on the closed-loop system stability. Experimental results of the proposed controller and the decentralized direct adaptive fuzzy controller are produced using MATLAB/SIMULINK external mode control on a single-link flexible-joint electrically driven robot. Experimental and analytical results demonstrate the high performance of the proposed control scheme. پرونده مقاله

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2 - Stability of Robust Lyapunov Based Control of Flexible-Joint Robots Using Voltage Control Strategy Revisited
Ali Deylami

Many advanced robot applications such as assembly and manufacturing require mechanical interaction of the robot manipulator with the environment. Any back-stepping based control strategy proposed for position control of electrical flexible joint robots requires a conver چکیده کامل

Many advanced robot applications such as assembly and manufacturing require mechanical interaction of the robot manipulator with the environment. Any back-stepping based control strategy proposed for position control of electrical flexible joint robots requires a convergence of internal signals to its desired value called a fictitious control signal. This problem is complicated and time-consuming, whereas a 5th-order nonlinear differential equation describes each joint of the robot. The best idea is to focus on the convergence of main signals while the other signals in the system remain bounded. With this in mind, this paper present a robust Lyapunov-based controller for the flexible joint electrically driven robot (FJER) considering input nonlinearities associated with actuator constraints. It also finds uncertainties associated with robot dynamics. The proposed approach is based on a third-order model instead of a fifth-order model of the robotic system. The stability is guaranteed in the presence of both structured and unstructured uncertainties. The actuator/link position errors asymptotically converge to zero while the other signals are bounded. Simulation results on a 2-DOF electrical robot manipulator effectively verify the efficiency of the proposed strategy. پرونده مقاله

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3 - Robust Fractional-order Control of Flexible-Joint Electrically Driven Robots
Payam Kheirkhahan

This paper presents a novel robust fractional PIλ controller design for flexible joint electrically driven robots. Because of using voltage control strategy, the proposed approach is free of problems arising from torque control strategy in the design and implemen چکیده کامل

This paper presents a novel robust fractional PIλ controller design for flexible joint electrically driven robots. Because of using voltage control strategy, the proposed approach is free of problems arising from torque control strategy in the design and implementation. In fact, the motor's current includes the effects of nonlinearities and coupling in the robot manipulator. Therefore, cancellation of motor current by feedback linearization in voltage control strategy can cancel the highly nonlinear dynamics of manipulators. Thus, it can guarantee robustness of control system to both structured and unstructured uncertainties associated with robot dynamics. As a result, the proposed control is simple, fast response and superior to torque control approaches. The control method is verified by stability analysis. Simulations on a two-link actuated flexible-joint robot show the effectiveness of the proposed control approach. Compared with ordinary controller, the fractional type shows a better tracking performance. پرونده مقاله

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4 - Integer-order Versus Fractional-order Adaptive Fuzzy Control of Electrically Driven Robots with Elastic Joints
Asghar Kebreyaeezade

Real-time robust adaptive fuzzy fractional-order control of electrically driven flexible-joint robots has been addressed in this paper. Two important practical situations have been considered: the fact that robot actuators have limited voltage, and the fact that current چکیده کامل

Real-time robust adaptive fuzzy fractional-order control of electrically driven flexible-joint robots has been addressed in this paper. Two important practical situations have been considered: the fact that robot actuators have limited voltage, and the fact that current signals are contaminated with noise. Through of a novel voltage-based fractional order control for an integer-order dynamical system and based on a Lyapunov's functions analysis, it is shown that the overall closed-loop system is robust, BIBO stable and the joint position tracking error is uniformly bounded. The satisfactory performance in lower energy consumption of the proposed fractional control scheme is verified in comparison with a standard integer-order controller by experimental results. پرونده مقاله

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5 - Robust Fractional Order Control of Under-actuated Electromechanical System
Mohammad Goodarzi

This paper presents a robust fractional order controller for flexible-joint electrically driven robots under imperfect transformation of control space. The proposed approach is free from manipulator dynamics, thus free from problems associated with torque control strate چکیده کامل

This paper presents a robust fractional order controller for flexible-joint electrically driven robots under imperfect transformation of control space. The proposed approach is free from manipulator dynamics, thus free from problems associated with torque control strategy in the design and implementation. As a result, the proposed controller is simple, fast response and superior to the torque control approaches. It can guarantee robustness of control system to both structured and unstructured uncertainties associated with robot dynamics. The control method is verified by stability analysis. Simulation results on a two-link actuated flexible-joint robot show the effectiveness of the proposed control approach. پرونده مقاله

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