Variable Admittance Control Strategy for the Control Stability of Power Assist Robot according to Load Weight

Abstract: An islanding detection and based control strategy is created in this exploration to accomplish the steady and independent activity of microgrids using the neural network based Virtual Synchronous Generator (VSG) idea during unplanned grid reconfigurations . Maybe of utilizing a design-orientedmethodology, this paper gives a rigorous and extensive hypothetical investigation and reaches a concise conclusion that is easy to execute and successful even in complex situations. Based on the results of the mutation sequence and voltage wavering, a neural network based islanding identification calculation is proposed, which requires less constraint strategy. The proposed neural network approach outperforms the thefrequency measured passive detection method in terms of detection speed and reliability. Broad recreations affirm the reasonableness of the proposed islanding location and control methodology. Additionally, think about the results of the reproductions for the PI regulator, fluffy organizations, and neural organizations. Keywords: Virtual Synchronous Generator, Islanding detection, Islanding operation, Droop control, Stability, Microgrids.

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Development of Mechanical-Impedance-Varying Mechanism in Admittance Control

Journal of Robotics and Mechatronics ◽

10.20965/jrm.2018.p0863 ◽

2018 ◽

Vol 30 (6) ◽

pp. 863-872

Author(s):

Toru Tsumugiwa ◽

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Miho Yura ◽

Atsushi Kamiyoshi ◽

Ryuichi Yokogawa

Keyword(s):

Motion Control ◽

Control Strategy ◽

Impedance Control ◽

Mechanical Impedance ◽

Force Sensor ◽

Robot Motion ◽

Admittance Control ◽

Input Force ◽

Mechanical Variable ◽

Impedance Parameters

There have been numerous studies on the physical human-robot cooperative task system with impedance/admittance control in robot motion control. However, the problem of stability persists, wherein the control system becomes unstable when the robot comes into contact with a highly stiff environment. A variable impedance control strategy was proposed to circumvent this stability problem. However, a number of studies on variable impedance control are based on the variation of a parameter in the robot motion control software, and a mechanical variable impedance control has not been proposed. The purpose of this research is to propose a mechanical variable impedance control strategy using a mechanical device based on the lever principle. The proposed mechanism can adjust the magnitude of the input force to the force sensor by changing the position of application of the operating force on the beam. Adjusting the magnitude of the input force to the force sensor is equivalent to varying the impedance parameters of the robot; therefore, it is feasible to achieve mechanical variable impedance control using the proposed mechanism. In this study, the gain adjustment characteristics of the proposed mechanism were evaluated. The experimental results demonstrated that the operator can vary the impedance parameters of the robot by mechanically adjusting the input force to the force sensor and operating the robot using the proposed mechanism.

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Virtual Coupling Based Control Methodology for Lower Extremity Exoskeleton

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.556-562.2365 ◽

2014 ◽

Vol 556-562 ◽

pp. 2365-2369 ◽

Cited By ~ 1

Author(s):

Jin Xiang Cui ◽

Yan He Zhu ◽

Ben Zhou Xu

Keyword(s):

Lower Extremity ◽

Control Strategy ◽

Degrees Of Freedom ◽

Virtual Prototype ◽

Contact Forces ◽

Admittance Control ◽

Collaborative Simulation ◽

Virtual Coupling ◽

Control Methodology ◽

Positional Control

As one of the most important examples of human-orientated system, the exoskeleton can improve the strength and endurance of the wearer. The exoskeleton has multi-degrees of freedom. As a result, a stable controller for the exoskeleton is difficult to design. The adoption of a purely positional control strategy may lead to large contact forces. Hence, an admittance control strategy is devised aimed at limiting both internal and contact forces. To verify the rationality and feasibility of the control strategy, we introduce a method utilizing virtual prototype and collaborative simulation.

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