A Simple Switching Control Structure for Improving the Steady-State Error of a Full-Digital Water-Hydraulic Cylinder Position Control

2010 ◽  
Author(s):  
Jyh-Chyang Renn ◽  
Shigeru Ikeo ◽  
Chin-Yi Cheng
Keyword(s):  
Steady State ◽  
Position Control ◽  
Control Structure ◽  
Hydraulic Cylinder ◽  
Switching Control ◽  
Water Hydraulic ◽  
State Error

Macro-Micro Dual-Drive Stages Based on Dual Switching Condition and Local Closed Loop

2015 ◽  
Author(s):  
Jiwen Fang ◽  
Zhili Long ◽  
Lufan Zhang
Keyword(s):  
Steady State ◽  
Theoretical Analysis ◽  
Closed Loop ◽  
Voice Coil Motor ◽  
Switching Control ◽  
Positioning Error ◽  
Vibration Displacement ◽  
Pzt Actuator ◽  
Output Displacement ◽  
State Error

This paper presents macro-micro dual-drive stages using the hybrid actuators composed of voice coil motor (VCM) and piezoelectric actuator (PZT actuator). The macro stage driven by voice coil motor can achieve large travel range and coarse positioning. The micro stage with an embedded flexure hinges mechanism, actuated by the PZT actuator, can realize short range but high precision positioning. To gain precise performance, the dynamic modes of macro stage and micro stage are equivalent to mass-damping-spring system in this research. According to theoretical analysis, the output displacement of micro stage is proportional to the extension of the PZT Actuator. The linear relationship will be used to the motion control of micro stage. To realize perfect performance, the variable gain PID controller is designed to control the macro stage. In order to prevent saturation and damage of PZT actuator, dual switching control, positioning error threshold and small vibration displacement, are applied to the switching control. Beyond the micro stage range, the micro stage must be kept in its equilibrium position while the VCM instead reaches a long travel. The PZT actuator controller is used to compensate for position error after switching control. When the error is less than a set thres hold value, the error signal is added into the micro control loop. So the macro-micro dual-drive stages are working together to reduce the positioning error. The relationship between PZT actuator of closed loop and input voltage is linear by theoretical analysis and experiment test. So the micro stage uses an open servo loop structure, but the PZT actuator is controlled with PI controller in local closed loop in order to eliminate the nonlinear of PZT. The experimental system used in this study is single-axis dual-driving stages. Turbo PMAC PCI-Lite is the core of the whole system and executes PLC programs with motion programs. Experiments show that the steady state error of dual-drive stage is nano level. The steady state error of dual-drive stage can be improved. So dual-drive stages can increase the positioning accuracy of the whole system and the performance is superior to the single VCM stage.

Two-Way Solenoid Valves in Low-Pressure Water Hydraulics

2000 ◽  
Author(s):  
Matti O. Linjama ◽  
Jyrki O. Tammisto ◽  
Kari T. Koskinen ◽  
Matti J. Vilenius
Keyword(s):  
Pressure Range ◽  
Position Control ◽  
Hydraulic Cylinder ◽  
Low Pressure ◽  
Weak Point ◽  
Flow Capacity ◽  
Water Hydraulics ◽  
Pressure Water ◽  
Small Flow ◽  
Water Hydraulic

Abstract The paper tests experimentally the suitability of inexpensive directly operated two-way solenoid valves for water hydraulic applications in the pressure range from 10 to 40 bars. Seven valves are tested and tested matters include the steady-state and dynamic characteristics as well as durability. Results show small delays and the durability of about ten million openings. The weak point of the valves is a small flow capacity but otherwise the valves are well suited for low-pressure water hydraulic applications. This is demonstrated by using them in a simple on/off position control of a water hydraulic cylinder.

Robot torque and position control using an electrorheological actuator

1998 ◽  
Vol 212 (3) ◽  
pp. 229-238 ◽  
Author(s):  
D J Brookfield ◽  
Z B Dlodlo
Keyword(s):  
Steady State ◽  
Applied Field ◽  
Position Control ◽  
Open Loop ◽  
Settling Time ◽  
Time Varying ◽  
Control Loop ◽  
Loop Transfer Function ◽  
Non Linear ◽  
State Error

An electrorheological (ER) clutch driven from a constant speed motor provides a steady torque independent of shaft angle and can be controlled by control of the applied field. Such an actuator avoids the ‘cogging’ variation in torque observed in d.c. servo-motors and is thus well suited to robot control applications, particularly in view of the very rapid time response of ER clutches (≍ 10−3 s). However, the relationship between applied field and torque is difficult to model, being both non-linear and time varying. Whereas the non-linearity can be shown to be relatively small, the time-varying characteristic has remained a problem. In most controlled plants, a non-linear or time-varying characteristic can be mitigated by providing a closed control loop around the plant. A PID (proportional plus integral plus derivative)-based torque controller was developed and tested. This was shown to be stable with at least critical damping and to exhibit low steady state error. Design of the controller was facilitated by the identification of the open-loop transfer function of the ER actuator. The ER actuator with torque feedback was used to position a small robot link. A second PID control loop responding to the error in the link position and tuned using the standard Ziegler and Nichols method was designed and tested. A steady state error of less than 0.75 mm was achieved with a 2 per cent settling time of 2.0 s. Finally, the link position was controlled using a single-loop controller with no torque feedback and a similar steady state error achieved with a 2 per cent settling time of 1.4 s. It is argued that the ER torque actuator is ideally suited to the actuation of robot joints where precise smooth movement is required.

High-Speed On/Off Position Control of a Low-Pressure Water Hydraulic Cylinder Drive

2002 ◽  
Author(s):  
Matti Linjama ◽  
Harri Sairiala ◽  
Kari T. Koskinen ◽  
Matti Vilenius
Keyword(s):  
High Speed ◽  
Position Control ◽  
Hydraulic Cylinder ◽  
Low Pressure ◽  
Pressure Water ◽  
Water Hydraulic

The Design of the Pilot Type Zero Steady-State Error of Water Hydraulic Overflow Valve

2012 ◽  
Vol 233 ◽  
pp. 104-108 ◽  
Author(s):  
Li Zhang ◽  
Jing Luo ◽  
Rui Bo Yuan ◽  
Yi Bo Zhang
Keyword(s):  
Steady State ◽  
Feedback Control ◽  
Closed Loop ◽  
Constant Pressure ◽  
Dynamic Pressure ◽  
Pressure Feedback ◽  
Loop Feedback ◽  
Closed Loop Feedback ◽  
Water Hydraulic ◽  
State Error

This paper studies on its cavitation and noise problem, according to traditional pressure controlling valve has a low accuracy of constant pressure, large leakage, poor lubrication, easy corrosion and so on, designs a new structure of pilot type of water hydraulic overflow valve based on the special physicochemical properties; Detecting the inlet pressure of the main valve with the help of the micro-pressure sensor and using closed-loop feedback control and dynamic pressure feedback control to eliminate steady-state error.

Proportional Position Control of Low-Pressure Water Hydraulic Cylinder

2002 ◽  
Author(s):  
Harri Sairiala ◽  
Matti Linjama ◽  
Kari T. Koskinen ◽  
Matti Vilenius
Keyword(s):  
Position Control ◽  
Hydraulic Cylinder ◽  
Low Pressure ◽  
Pressure Water ◽  
Water Hydraulic

Modeling and Its Error Analysis for Load-Sensing Steering System

2013 ◽  
Vol 694-697 ◽  
pp. 678-682
Author(s):  
Hai Fang Wang ◽  
Xiao Guang Ren ◽  
Yu Rong
Keyword(s):  
Steady State ◽  
Transfer Function ◽  
Input Signal ◽  
Position Control ◽  
Steering System ◽  
Force Balance ◽  
Energy Effect ◽  
Load Sensing ◽  
Hydraulic Steering ◽  
State Error

Load-sensing hydraulic steering system is universally used in wheeled machinery for good steering regulation performance and obviously saving energy effect. The load-sensing hydraulic steering system is present, and it is considered to be a mechanical and hydraulic position control system. The flow continuity equation and force balance equation of steering system is established, the transfer function of load-sensing hydraulic steering system is obtained, the system steady-state error caused by the typical input signal and load input signal on the basis of transfer function. The main parameters affecting the steady-state error are got, and it provides theoretical support for designing and improvement of load-sensing hydraulic steering system.

An anti-windup rate-varying integral control applied to electromechanical actuator

2014 ◽  
Vol 229 (4) ◽  
pp. 692-702
Author(s):  
Mohammad Reza Sabaapour ◽  
Esmaeel Khanmirza ◽  
Siamak Ghadami
Keyword(s):  
Steady State ◽  
Trajectory Tracking ◽  
Position Control ◽  
Nonlinear Modeling ◽  
External Disturbance ◽  
Error Signal ◽  
Integral Control ◽  
Electromechanical Actuator ◽  
Good Agreement ◽  
State Error

This paper introduces a novel integral-based controller to correct steady-state error as well as to improve trajectory tracking in position control of a rotary actuator. For this aim, linear and nonlinear modeling of a rotary electromechanical actuator via conventional P-D controller has been described followed by investigation of nonlinear element's effects. The model has very good agreement with experimental results. Then, for trajectory tracking improvement and especially to reduce steady-state error induced by external disturbance, different integral based controllers such as PID, PI-D, and I-PD have been considered. Moreover, the problem of integrator saturation (integral wind-up) has been solved by modified rate varying integral method. It has been showed that a PI-D controller with modified rate varying integral can best match controlling requirements, as well as having enough simplicity for analogue implementation. Also, as a new method, it was suggested that for rate-varying integral calculation, the error rate signal could be replaced by error signal. Doing so, not only former advantages were hold, but more simplicity in controller implementation was gained. Simulation results have shown the effectiveness of the proposed method.

Sign in / Sign up

Export Citation Format

Share Document