scholarly journals Development of a Four-Way Pinch-Type Servo Valve for Pneumatic Actuator

2020 ◽  
Vol 10 (3) ◽  
pp. 1066
Author(s):  
Kotaro Tadano ◽  
Yasumasa Ishida ◽  
Hisami Takeishi
Keyword(s):  
Position Control ◽  
Flow Characteristics ◽  
Pneumatic Actuator ◽  
Pneumatic Cylinder ◽  
Heavy Load ◽  
Servo Systems ◽  
Air Compressor ◽  
Servo Valve ◽  
Robot Systems ◽  
Control Application

Pneumatic servo valves are key components of pneumatic servo systems. Multi-degree-of-freedom systems, such as robot systems, utilize many servo valves to control their actuators. However, conventional servo valves always consume air due to leakage even when the pneumatic actuator is not moving. Hence, the consumption flow rate of the entire system corresponds to a heavy load on the air compressor. Reduction in the leakage of servo valves contributes to lower requirements for the air compressor and saves energy. In this study, we develop a four-way pinch- type pneumatic servo valve that controls flow rates by pinching air tubes to realize a leak-free servo valve. A cam to control the aperture of the flow channel is newly designed, and a control system is established. Measurement results indicate high linearity in static flow characteristics and high dynamic characteristics corresponding to 30 Hz. We experimentally confirm a good position tracking property in the position control of a pneumatic cylinder by using the developed valve. Finally, evaluation results of air consumption in a robotic control application indicate that the developed valve contributes to a significant reduction in air consumption compared to that of a conventional spool-type valve.

Analysis of an Opto-Pneumatic Control System and Improvement of its Control Performance

1999 ◽  
Vol 11 (4) ◽  
pp. 251-257 ◽  
Author(s):  
Tetsuya Akagi ◽  
◽  
Shujiro Dohta ◽  
Hisashi Matsushita ◽  
Keyword(s):  
Control System ◽  
Position Control ◽  
Sliding Mode ◽  
Pneumatic Cylinder ◽  
Control Performance ◽  
Pneumatic Control ◽  
Servo Valve ◽  
Proposed Model ◽  
Control Scheme

This paper describes an analysis of an opto-pneumatic control system and an improvement of control performance of the system. The opto-pneumatic system consists of an optical servo valve, a pneumatic cylinder and a cart. First, we built an analytical model of the system considering a nonlinear friction where exists in sliding parts. And we confirmed the validity of the proposed model by comparing theoretical results with experimental results of the characteristics of optical servo valve and cart position control. Then, we applied a sliding mode control scheme compensating a steady-state disturbance to multi- position control and follow-up control of a cart. By computer simulation, we confirmed that the control performance of opto-pneumatic control system was improved by using this control scheme.

Integrated Control Design of Pneumatic Servo Table Considering the Dynamics of Pipelines and Servo Valve

2011 ◽  
Vol 5 (4) ◽  
pp. 485-492 ◽  
Author(s):  
Jun Li ◽  
◽  
Joonmyeong Choi ◽  
Kenji Kawashima ◽  
Toshinori Fujita ◽  
...  
Keyword(s):  
Linear Model ◽  
Integrated Control ◽  
Control Design ◽  
Pneumatic Actuator ◽  
Pneumatic Cylinder ◽  
Order Model ◽  
Servo Valve ◽  
Comparison Results ◽  
Valve Dynamics ◽  
High Dynamics

In this paper, integrated control design for the pneumatic servo table system considering the dynamics of pipelines and servo valve is studied. The table is mainly composed by a pneumatic actuator, a highperformance pneumatic servo valve and pipelines. The pneumatic actuator utilizes a pneumatic cylinder with air bearings. The servo valve has high dynamics up to 300 Hz and is connected to the pneumatic actuator by pipelines. The system is pneumatically driven, providing the advantages of low heat generation and non-magnetic, nature suited to precise positioning. To simulate the system, we designed a linear model considering pipelines and servo valve dynamics. Comparison results showed that with a 7thorder linear model, the discrepancy between experiment and simulation results was much smaller than when using a 3rdorder model. The model’s complexity made it necessary to reduce the model’s order. Two poles are much further from the imaginary axis compared with other five poles in the pole loci of the 7thorder model, so the model is reduced to a 5thorder. A comparison of simulation and experiment results showed that the 5thorder model matches the real system well.

scholarly journals Trajectory Control of Pneumatic Servo Table with Air Bearing

2011 ◽  
Vol 5 (6) ◽  
pp. 800-808 ◽  
Author(s):  
Jun Li ◽  
◽  
Kotaro Tadano ◽  
Kenji Kawashima ◽  
Toshinori Fujita ◽  
...  
Keyword(s):  
High Performance ◽  
Control Design ◽  
Trajectory Control ◽  
Pneumatic Actuator ◽  
Pneumatic Cylinder ◽  
Air Bearing ◽  
Order Model ◽  
Servo Valve ◽  
High Dynamics ◽  
Low Dimensional

This paper proposes a trajectory control design for a pneumatic servo table system. The control design takes into consideration the dynamics of the pneumatic actuator, connected pipeline and servo valve. The system is mainly composed of a pneumatic actuator, high-performance pneumatic servo valves and pipelines. The pneumatic actuator utilizes a pneumatic cylinder with air bearing. The servo valve, which has high dynamics up to 300 Hz, is connected to the pneumatic actuator by pipelines. A linear model which takes into consideration the dynamics of the pipeline and servo valve is designed to simulate the system. Experiment results suggest that with 7thorder control model the system can be accurately represented. However, a low-dimensional model is necessary for practical use. The analysis shows that in the pole loci of the 7thorder model, two poles are much farther from the imaginary axis than are the other five poles. Therefore, the model can be reduced to one of the 5thorder. By comparing the simulation and experiment results, we confirm that the 5thorder model can also match the system well. Based on this result, a 5thorder feed forward has been designed. When a curve which can be derived five times is inputted, the experiment results show that the maximum trajectory error has been reduced by 20 µm.

scholarly journals Proposal of a Decoupled Structure of Fuzzy-PID Controllers Applied to the Position Control in a Planar CDPR

Electronics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 745
Author(s):  
Marco Carpio ◽  
Roque Saltaren ◽  
Julio Viola ◽  
Cristian Calderon ◽  
Juan Guerra
Keyword(s):  
Position Control ◽  
Control Structure ◽  
Parallel Robot ◽  
Pid Controllers ◽  
Fuzzy Pid ◽  
End Effector ◽  
Robot Systems ◽  
Decoupled Control ◽  
The Mathematical Model ◽  
Decoupled Structure

The design of robot systems controlled by cables can be relatively difficult when it is approached from the mathematical model of the mechanism, considering that its approach involves non-linearities associated with different components, such as cables and pulleys. In this work, a simple and practical decoupled control structure proposal that requires practically no mathematical analysis was developed for the position control of a planar cable-driven parallel robot (CDPR). This structure was implemented using non-linear fuzzy PID and classic PID controllers, allowing performance comparisons to be established. For the development of this research, first the structure of the control system was proposed, based on an analysis of the cables involved in the movement of the end-effector (EE) of the robot when they act independently for each axis. Then a tuning of rules was carried out for fuzzy PID controllers, and Ziegler–Nichols tuning was applied to classic PID controllers. Finally, simulations were performed in MATLAB with the Simulink and Simscape tools. The results obtained allowed us to observe the effectiveness of the proposed structure, with noticeably better performance obtained from the fuzzy PID controllers.

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