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 ◽  
...  

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.

2011 ◽  
Vol 5 (6) ◽  
pp. 800-808 ◽  
Author(s):  
Jun Li ◽  
◽  
Kotaro Tadano ◽  
Kenji Kawashima ◽  
Toshinori Fujita ◽  
...  

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.


2020 ◽  
Vol 10 (3) ◽  
pp. 1066
Author(s):  
Kotaro Tadano ◽  
Yasumasa Ishida ◽  
Hisami Takeishi

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.


2020 ◽  
Vol 102 ◽  
pp. 104530
Author(s):  
Ricardo G. Teodoro ◽  
Willian R.B.M. Nunes ◽  
Rafael A. de Araujo ◽  
Marcelo A.A. Sanches ◽  
Marcelo C.M. Teixeira ◽  
...  

1998 ◽  
Vol 122 (1) ◽  
pp. 237-239 ◽  
Author(s):  
S. O. Reza Moheimani

The modal analysis approach to modeling of structures and acoustic systems results in infinite-dimensional models. For control design purposes, these models are simplified by removing higher frequency modes which lie out of the bandwidth of interest. Truncation can considerably perturb the in-bandwidth zeros of the truncated model. This paper suggests a method of minimizing the effect of the removed higher order modes on the low frequency dynamics of the truncated model by adding a zero frequency term to the low order model of the system. [S0022-0434(00)01501-X]


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