Optimized Pulse Modulation: A Novel Idea of a Digital Control Method for On/Off Valves

Author(s):  
Ingo Schepers ◽  
Daniel Weiler ◽  
Juergen Weber

This article describes how on/off valves can be used in the closed loop control. After studying different industrial hydraulic applications typical requirements will be compiled. From these requirements a basic on/off valve architecture will be derived. In this article the number of parallel connected on/off valves per control edge is limited to one valve. So the typical digital hydraulics with a high number of parallel connected valves is not considered. The on/off valves could not be controlled like normal directional valves. To control on/off valves digital control methods are common to use. The digital control methods are not optimized for the hydraulic on/off valves, because the origins of the digital control methods will be found in the electrical engineering. The novel idea for the digital control methods is the optimized pulse control which eliminates the disadvantages of the common digital control methods. How the optimized pulse control works is described in this article.

2009 ◽  
Vol 628-629 ◽  
pp. 257-262 ◽  
Author(s):  
Tong Xing

The cutter head drive hydraulic system of φ1.8m simulate shield machine is introduced in this article, which has the variable speed pump control technique and the closed loop control method. The AMESim simulation model of the hydraulic system is built up, and the efficiency of the hydraulic system, speed control performance by open loop and closed loop control are analyzed. The result of the simulation shows that the variable speed pump control system has higher efficiency than the variable displacement pump control system about 4%-26% in the same condition when the cutter head speed is at the range of 0.5-4r/min, and the hydraulic system has good dynamic characteristics in closed-loop PID control.


2016 ◽  
Author(s):  
Insoo Jung ◽  
Jaemin Jin ◽  
Dongchul Lee ◽  
Seunghyun Lee ◽  
Seungwook Yang ◽  
...  

Author(s):  
Long Chen ◽  
Haoxiang Wang ◽  
Xiaodong Sun ◽  
Yingfeng Cai ◽  
Ke Li ◽  
...  

A novel four-phase 16/10 belt-driven starter generator segmented switched reluctance motor has been proposed in a previous work to reduce torque ripple and increase the fault tolerance ability. Based on the previous research, the segmented switched reluctance motor digital control system is designed and presented. The digital control system including a power converter, detection circuits, and protection circuits is introduced in detail. For detection circuits, the half-detection method is employed to decrease the cost of the system. In addition, based on MicroAutoBox DS1401, a rapid control prototype platform is established. With this software system, it is easy to transfer control models and realize real-time control directly. Then, the speed closed closed-loop control for the segmented switched reluctance motor is applied to verify the proposed system. It contains current chopper control at a low speed and angle position control at a high speed. The simulation results are given, including the flux, current, torque, and efficiency range over the entire speed range of the segmented switched reluctance motor. Finally, the experimental results are presented to verify the simulation results and the effectiveness of the system. It can be found that the simulation and experimental results are consistent and acceptable, which means that the proposed digital system can operate naturally and accurately under speed closed loop control. Hence, the proposed digital system has high compatibility and practicability.


2005 ◽  
Vol 17 (01) ◽  
pp. 19-26 ◽  
Author(s):  
CHENG-LIANG LIU ◽  
CHUNG-HUANG YU ◽  
SHIH-CHING CHEN ◽  
CHANG-HUNG CHEN

Functional electrical stimulation (FES) is a method for restoring the functional movements of paraplegic or patients with spinal cord injuries. However, the selection of parameters that control the restoration of standing up and sitting functions has not been extensively investigated. This work provides a method for choosing the four main items involved in evaluating the strategies for sit-stand-sit movements with the aid of a modified walker. The control method uses the arm-supported force and the angles of the legs as feedback signals to change the intensity of the electrical stimulation of the leg muscles. The control parameters, Ki and Kp, are vary for different control strategies. Four items are collected through questionnaires and used for evaluation. They are the maximum reactions of the two hands, the average reaction of the two hands, largest absolute angular velocity of the knee joints, and the sit-stand-sit duration time. The experimental data are normalized to facilitate comparison. Weighting factors are obtained and analyzed from questionnaires answered by experts and are added to evaluation process for manipulation. The results show that the best strategy is the closed-loop control with parameters Ki=0.5 and Kp=0.


2012 ◽  
Vol 203 ◽  
pp. 226-230
Author(s):  
Peng Chen ◽  
Jian Yang Zhai ◽  
Zheng Zhu

Combining with some fuzzy of the direct torque control and the fuzzy control which is often used in the traditional AC motor control,we put forward a direct torque control theory based on the fuzzy rule. The brushless doubly-fed machine(BDFM) closed-loop control system with the direct torque control based on the fuzzy rule is simulated by using of the Matlab/Simulink software, and the simulation results show that the closed-loop control method is correct and effective.


2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Zhiqiang Wang ◽  
Haibao Nan ◽  
Tingna Shi ◽  
Qiang Geng ◽  
Changliang Xia

In a winding system, it is very important to control the tension precisely. Based on the process of rewinding and unwinding, a sensorless tension control method with PI parameters of adaptive speed controllers is proposed in this paper. According to the principle of torque balance, a tension observer is designed to replace the tension sensor, and the observed value instead of the measured value of tension is used as feedback. Then the measurement delay caused by tension sensor is reduced. For the time-variable inertia, Landau discrete-time recursive algorithm is used to estimate the inertias of the rewind and unwind motors. Moreover, the estimated inertias are used to adjust the PI parameters of the speed controllers. As the tension control system has the ability to adapt to the change of inertia, its dynamic performance is improved to some extent. In addition, the proposed sensorless tension control method is simple and easy to implement, which only uses the current and speed signals of the motors without any additional hardware needed. At last, the feasibility and effectiveness of the proposed method are verified by the experimental results.


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