Design and Performance of Nonlinear Control for an Electro-Hydraulic Actuator Considering a Wearable Robot

Song, Bomi; Lee, Dongyoung; Park, Sang Yong; Baek, Yoon Su

doi:10.3390/pr7060389

Cited by 18 publications

(13 citation statements)

References 20 publications

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“…An EHA system of enlarging the human knee joint capacity was studied in Refs. [22,23] which realized the EHA firstly used in the assisted single joint. The pump-controlled system indeed has the potential of being the power unit in robots.…”

Section: Introductionmentioning

confidence: 99%

One Novel Hydraulic Actuating System for the Lower-Body Exoskeleton

Sun

Ouyang

Mattila

et al. 2021

Chin. J. Mech. Eng.

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The hydraulic exoskeleton is one research hotspot in the field of robotics, which can take heavy load due to the high power density of the hydraulic system. However, the traditional hydraulic system is normally centralized, inefficient, and bulky during application, which limits its development in the exoskeleton. For improving the robot’s performance, its hydraulic actuating system should be optimized further. In this paper a novel hydraulic actuating system (HAS) based on electric-hydrostatic actuator is proposed, which is applied to hip and knee joints. Each HAS integrates an electric servo motor, a high-speed micro pump, a specific tank, and other components into a module. The specific parameters are obtained through relevant simulation according to human motion data and load requirements. The dynamic models of the HAS are built, and validated by the system identification. Experiments of trajectory tracking and human-exoskeleton interaction are carried out, which demonstrate the proposed HAS has the ability to be applied to the exoskeleton. Compared with the previous prototype, the total weight of the HAS in the robot is reduced by about 40%, and the power density is increased by almost 1.6 times.

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Section: Introductionmentioning

confidence: 99%

One Novel Hydraulic Actuating System for the Lower-Body Exoskeleton

Sun

Ouyang

Mattila

et al. 2021

Chin. J. Mech. Eng.

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“…Electro-hydraulic servo pump control technology plays a very important role in highprecision control fields, e.g., aircraft rudder surface control [1], robot joint drives [2], and wind power variable paddle control [3], and is a core technology in industrial development. The electro-hydraulic servo pump control system (EHSPCS) adopts the concept of volumetric speed regulation under the permanent magnet synchronous motor (PMSM) drive mechanism.…”

Section: Introductionmentioning

confidence: 99%

The Thermal Balance Temperature Field of the Electro-Hydraulic Servo Pump Control System

et al. 2021

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The electro-hydraulic servo pump control system (EHSPCS) is a high-performance control unit that integrates a permanent magnet synchronous motor (PMSM) and a closed hydraulic system (CHS). The design features of high integration and a high power-weight ratio lead to the poor heat dissipation capacity and high thermal balance temperature of the system. Excessive temperature will seriously affect the system’s performance and service life. Therefore, the thermal balance analysis method of the EHSPCS under different loads and different wind speeds was proposed in this paper. Firstly, the PMSM and CHS were taken as research objects to analyze the heating source of the system. The thermal power model was established, and the calculation was performed. The variation rule of the thermal power generated by each component with the load torque under the typical rotating speed was obtained. Secondly, the system’s temperature field thermal balance solution model was established. ANSYS and AMESim software were used to calculate the thermal balance points of the PMSM and CHS under different working conditions. The change rule of the thermal balance temperature field of the EHSPCS under different loads was analyzed with the conditions of the natural cooling and forced wind cooling of the PMSM. Finally, an experimental platform was built for experimental research, and the experimental temperature of the system under different loads and different wind speeds was measured. Through comparison and analysis with the simulation results, the correctness and feasibility of the thermal balance theoretical analysis method were verified. The research results will lay the foundation for thermal balance research on the EHSPCS, and have guiding significance for system design, component selection, and load matching.

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“…Similarly, references [15][16][17] researched nonlinear control, such as a robust adaptive fuzzy neural network control algorithm to design a PID controller for heading control of unmanned marine vehicles and a Non-Linear Dynamic Inversion Control to compare the primary differences between three multi-rotor platforms, and a closed-loop control system were implemented where applicable. Some other nonlinear control models were also established and proposed from different perspectives [18][19][20][21]. Be that as it may, all aforementioned references were researched thoroughly from different points of view and attained certain achievements with respects to water tank level control by using different control modes.…”

Section: Introductionmentioning

confidence: 99%

Inverse Tangent Functional Nonlinear Feedback Control and Its Application to Water Tank Level Control

Zhao

Zhang

2020

Processes

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This paper explores the significance and feasibility of addressing a notion that the system error of a nonlinear feedback control can be decorated by an inverse tangent function in order to attain a sound energy-efficient performance. The related mathematical model and relevant evaluation of this concept are further illustrated by demonstrating a case study about the control performance of water tank level. The rationale of robust control and theoretical algorithm of Lyapunov stability theorem are outlined to evaluate the effectiveness of nonlinear feedback with inverse tangent function in terms of improving robustness of PID (Proportional–Integral–Derivative) controller and energy-saving capability. By demonstrating five simulations of different scenarios, it ultimately proves that the modified robust PID controller by inverse tangent function meets the requirement of energy-saving capacity. Comparing with the routine PID control, the mean control input of controlling water tank level can be reduced up to 39.2% by using modified nonlinear feedback controller. This nonlinear feedback PID controller is energy efficient and concise for its convenient use, which is feasible to expand its utility to other applications.

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Design and Performance of Nonlinear Control for an Electro-Hydraulic Actuator Considering a Wearable Robot

Cited by 18 publications

References 20 publications

One Novel Hydraulic Actuating System for the Lower-Body Exoskeleton

One Novel Hydraulic Actuating System for the Lower-Body Exoskeleton

The Thermal Balance Temperature Field of the Electro-Hydraulic Servo Pump Control System

Inverse Tangent Functional Nonlinear Feedback Control and Its Application to Water Tank Level Control

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