The Dynamic Characteristics of an Electro-Hydraulic Servovalve

1976 ◽  
Vol 98 (4) ◽  
pp. 395-406 ◽  
Author(s):  
D. J. Martin ◽  
C. R. Burrows
Keyword(s):  
Control System ◽  
Steady State ◽  
Dynamic Characteristics ◽  
Position Control ◽  
Experimental System ◽  
Second Order ◽  
Frequency Responses ◽  
Model Based ◽  
Valve Model ◽  
Position Control System

The frequency responses of an experimental electro-hydraulic position control system and a simulation of the system are compared. Three different valve models are used in the simulation in an attempt to highlight the important parameters of an electro-hydraulic servovalve. It is found that a second order compensated valve model based on steady-state considerations provides a good correlation with the experimental system up to 35Hz and can be used for stability calculations up to 80Hz.

Electrostatic Suspension System for Gyroscopes with Minimum Electrical Disturbing Torque via Non-Linear Pre-Compensation

1996 ◽  
Vol 210 (2) ◽  
pp. 123-127 ◽  
Author(s):  
W Q Yang
Keyword(s):  
Control System ◽  
Steady State ◽  
Position Control ◽  
Complete System ◽  
Suspension System ◽  
System Operation ◽  
Non Linear ◽  
Position Control System ◽  
Transient And Steady State ◽  
Steady State Performance

The new electrostatic suspension system (ESS) presented here is applicable to electrostatically suspended gyroscopes (ESG). The electrical disturbing torque (EDT) acting on the gyro rotor is reduced to much lower levels than possible with the conventional methods, thereby increasing the attainable accuracy of the instrument. This is achieved by eliminating the conventional pre-load voltage and instead applying only control voltages via an analogue non-linear pre-compensator to achieve linear position control system operation despite the square law relating the suspension force to the applied voltage. The transient and steady state performance of the complete system, with changes in position reference and external disturbing forces, are examined with the aid of computer simulations.

scholarly journals A Nonlinear Model-Based Variable Input Control for the Position Control System of HDU

IEEE Access ◽  
2018 ◽  
Vol 6 ◽  
pp. 67742-67751
Author(s):  
Bin Yu ◽  
Qi-Xin Zhu ◽  
Kai-Xian Ba ◽  
Zheng-Guo Jin ◽  
Zheng-Jie Gao ◽  
...  
Keyword(s):  
Control System ◽  
Nonlinear Model ◽  
Position Control ◽  
Model Based ◽  
Input Control ◽  
Position Control System

Angular Position Control of Fluid-Driven Spindle

2009 ◽  
Author(s):  
Yohichi Nakao ◽  
Naoya Asaoka
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Steady State ◽  
Disturbance Observer ◽  
Position Control ◽  
Angular Position ◽  
Experimental Results ◽  
The Mathematical Model ◽  
Position Control System ◽  
State Error

A precise spindle is essential to achieve precision machining, such as diamond turning. A fluid driven spindle supported by hydrostatic bearings was thus designed and tested. A feature of the spindle is that several flow channels are designed in its rotor so that driving torque can be generated by supplying pressurized flow into the channels. Rotational speed of the spindle can be controlled by the flow rate. In addition, the rotational direction of the spindle can be controlled by switching supply ports. Thus angular position control of the spindle is achieved by designing appropriate feedback controller. In the present paper, mathematical model of the spindle was thus derived in order for designing an angular position control system. Then spindle characteristics calculated by the mathematical model were compared with experimental results. Furthermore, the angular position control system that has a disturbance observer in its feedback loop was designed based on the mathematical model. The performance of the designed control system was experimentally investigated through the step response. Experimental results verified that the designed controller minimizes the steady state error of angular position of the spindle. Consequently, the steady state error was comparable with the resolution of the rotary encoder, 0.018 degree. In particular, the experimental results indicated that the disturbance observer effectively reduced the influence of various load torque on the angular position of the spindle.

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