Digital servo control of hydraulic actuator: stepper motion problem

The purpose of this paper is to develop an approach to improve the tracking characteristics of a single axis shaking table actuation system, which is used in active structural control system. Firstly, the process of constructing analytical model of servo-hydraulic actuation system is presented. The proposed model, in the form of the total shaking table transfer function, accounts for the specific physical characteristics of the single axis shaking table. Due to low natural frequency and small hydraulic actuator damping, the single axis shaking table cannot meet the experimental requirement Therefore, three states feedback and three state feed-forward control algorithm based on pole-assignment principle is applied to extend the acceleration bandwidth. Lastly, the shaking table experiments are tested and the experimental results indicate that the controller is effective and reliable.

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Hydraulic pan-tilt servo control system based on hydraulic actuator model

2017 Chinese Automation Congress (CAC) ◽

10.1109/cac.2017.8243398 ◽

2017 ◽

Author(s):

Kaihao Zhang ◽

Xuewen Rong ◽

Kun Yang ◽

Yibin Li ◽

Hui Chai

Keyword(s):

Control System ◽

Servo Control ◽

Hydraulic Actuator ◽

Servo Control System

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A Semi-Active Damper Design for Use in a Terrain Adaptive Ankle Prosthesis

Volume 7: Dynamic Systems and Control; Mechatronics and Intelligent Machines, Parts A and B ◽

10.1115/imece2011-65533 ◽

2011 ◽

Cited By ~ 3

Author(s):

Andrew LaPre` ◽

Frank Sup

Keyword(s):

Control Valve ◽

Servo Control ◽

Heel Strike ◽

Hydraulic Actuator ◽

Dynamic Damping ◽

Human Ankle ◽

Performance Specifications ◽

Damper Design ◽

Active Damper ◽

The Mathematical Model

State-of-the-art commercial ankle prostheses enable amputees to walk on level ground replicating the passive biomechanics of able-bodied persons reasonably well. However, when navigating uneven terrains (such as slopes and stairs) these devices do not allow the ankle to adjust to the ground at each step in order to maintain stable contact. At these instances, the probability of falling is greatly increased. In contrast, the natural ankle adapts passively (i.e. no net positive power is required) just after heel strike allowing the foot to conform to the ground. This paper focuses on developing a continuously variable damper that can be paired with a carbon fiber foot in order to replicate the passive adaption dynamics of the human ankle. Presented in this paper are the performance specifications, the mathematical model, and the resulting device design for the semi-active damping system. The design consists of a hydraulic actuator, coupled to a servo control valve which modulates the damping. The system is designed to replicate the dynamic damping range of an able-bodied ankle joint by achieving flow rates as high as 2.0 liters per minute at 1.0 MPa, and operate at up to 20 MPa.

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Intelligent supervision of servo control

IEE Proceedings D Control Theory and Applications ◽

10.1049/ip-d.1993.0053 ◽

1993 ◽

Vol 140 (6) ◽

pp. 405 ◽

Cited By ~ 6

Author(s):

M.H. Perng ◽

H.H. Chang

Keyword(s):

Servo Control

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Control of Vibrations due to Moving Loads on Suspension Bridges

Nonlinear Analysis Modelling and Control ◽

10.15388/na.2006.11.3.14749 ◽

2006 ◽

Vol 11 (3) ◽

pp. 293-318 ◽

Cited By ~ 4

Author(s):

M. Zribi ◽

N. B. Almutairi ◽

M. Abdel-Rohman

Keyword(s):

Bridge Deck ◽

Suspension Bridge ◽

Lyapunov Theory ◽

Dynamic Responses ◽

Suspension Bridges ◽

Control Force ◽

Moving Loads ◽

Hydraulic Actuator ◽

Long Span ◽

Suspended Cables

The flexibility and low damping of the long span suspended cables in suspension bridges makes them prone to vibrations due to wind and moving loads which affect the dynamic responses of the suspended cables and the bridge deck. This paper investigates the control of vibrations of a suspension bridge due to a vertical load moving on the bridge deck with a constant speed. A vertical cable between the bridge deck and the suspended cables is used to install a hydraulic actuator able to generate an active control force on the bridge deck. Two control schemes are proposed to generate the control force needed to reduce the vertical vibrations in the suspended cables and in the bridge deck. The proposed controllers, whose design is based on Lyapunov theory, guarantee the asymptotic stability of the system. The MATLAB software is used to simulate the performance of the controlled system. The simulation results indicate that the proposed controllers work well. In addition, the performance of the system with the proposed controllers is compared to the performance of the system controlled with a velocity feedback controller.

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