Optimization of orifice position in particle-excitation valve for proportional flow control

ROBOMECH Journal, Oct 2017

This paper reports an improvement of the particle-excitation flow control valve. The valve that we have designed in previous reports can control air flow, using particle excitation by piezoelectric resonance, and has the following advantages: small size, lightweight, high response and continuous airflow control. However, in our previous models, the relationship between the driving voltage and the flow quantity was nonlinear. In this report, we improved the valve to realize proportional flow control. The valve consists of the orifice plate, that has some orifices, and steel particles to seal the orifices and piezoelectric transducer. It controls air flow by the voltage applied to the transducer. For proportional flow control, it is important to adjust the orifice position adequately. In this report, we optimized the orifice position, considering resonance condition of the valve. We designed the experimental prototype using a bolt-clamped Langevin type transducer and decided orifice position. And we evaluated its vibration properties and flow-rate characteristics. The experimental results showed that our designed prototype can proportionally control airflow.

A PDF file should load here. If you do not see its contents the file may be temporarily unavailable at the journal website or you do not have a PDF plug-in installed and enabled in your browser.

Alternatively, you can download the file locally and open with any standalone PDF reader:

https://robomechjournal.springeropen.com/track/pdf/10.1186/s40648-017-0093-3

Optimization of orifice position in particle-excitation valve for proportional flow control

Hirooka et al. Robomech J Optimization of orifice position in particle-excitation valve for proportional flow control Daisuke Hirooka 0 Tomomi Yamaguchi 0 Naomichi Furushiro 0 Koichi Suzumori 2 Takefumi Kanda 1 0 Department of Mechanical Engineering, Kansai University , 3-3-35, Yamate-cho, Suita-shi, Osaka 564-8680 , Japan 1 Graduate School of National Science and Technology, Okayama University , 3-1-1 Tsushima-naka, Okayama 700-8530 , Japan 2 Graduate School of Engineering, Tokyo Institute of Technology , 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 , Japan This paper reports an improvement of the particle-excitation flow control valve. The valve that we have designed in previous reports can control air flow, using particle excitation by piezoelectric resonance, and has the following advantages: small size, lightweight, high response and continuous airflow control. However, in our previous models, the relationship between the driving voltage and the flow quantity was nonlinear. In this report, we improved the valve to realize proportional flow control. The valve consists of the orifice plate, that has some orifices, and steel particles to seal the orifices and piezoelectric transducer. It controls air flow by the voltage applied to the transducer. For proportional flow control, it is important to adjust the orifice position adequately. In this report, we optimized the orifice position, considering resonance condition of the valve. We designed the experimental prototype using a boltclamped Langevin type transducer and decided orifice position. And we evaluated its vibration properties and flowrate characteristics. The experimental results showed that our designed prototype can proportionally control airflow. Proportional flow control valve; Pneumatic valve; Pneumatic actuator; PZT; Flow control valve Background A pneumatic actuation system has many advantages, including lightweight, safety, and low cost. Because pneumatic actuators have compliance, they are widely researched for human support devices [ 1–5 ]. Recently, the actuators are examined as the application of artificial muscles and soft actuators [ 6–10 ]. However, it is difficult to control pneumatic equipment since air is compressible and has nonlinear characteristics. Therefore, highly controllable devices are in great demand. Many kinds of pneumatic control devices have been researched [ 11–28 ]. Especially, piezoelectric (PZT) actuators are widely used [ 14–22, 24–28 ] because some of these actuators have high response and large power. Because the strokes of PZT actuators are very small and must be increased, some researches use laminated PZTs [ 17–19 ], bimorph structure [ 16 ], motors [ 20, 21, 24 ], or displacement amplifier mechanisms [ 25–28 ]. Especially for proportional or servo valves, since the stroke of the actuated part is critical, displacement amplifier mechanisms are used. A valve with displacement amplifier mechanisms is heavy and large. We designed flow control valves using particle excitation mechanism whose advantages are small size and high response [ 29–32 ]. This control mechanism uses PZT resonance frequency and does not need the displacement amplifier mechanism. In previous report, we demonstrated its basic structure and confirmed that it has potential to provide a large flow rate [ 29 ]. We showed new mechanism of the valve using deferent types of particles for stable flow control [ 30 ]. We discussed orifice condition of the valve and designed prototype that can control air flow continuously [ 31 ]. And we expanded orifices diameter to increase flow quantity and checked responsiveness of the valve [ 32 ]. However, the flow conditions of the prototypes were nonlinear. In this report, we proposed a new model of particle-excitation valve that can realize the proportional flow control. For proportional flow control, we optimized the orifice position considering vibration mode. Firstly, we showed the basic mechanism and then specifically explained its design, how the valve makes the flow condition proportional. Secondly, we designed a prototype optimizing the orifice position. To decide orifice position, we used the approximation of orifice deformation shape. Next we showed the designed prototype’s basic characteristics. Finally, we provided the results of a flow rate change experiment and explained the flow rate characteristics. Proportional mechanism using particle excitation valve Basic control mechanism of particle excitation Firstly, we explain the basic principle of the previously designed particle-excitation mechanism [ 29 ]. Figure  1 shows a cross section of a flow control valve and establishes its basic working principle using particle excitation. This valve consists of an orifice plate, a piezoelectric transducer, and steel particles. The orifice plate is located at the transducer’s antinode. Figure  1a depicts the valve in non-driving state. Airflow is supplied from the airport, (...truncated)


This is a preview of a remote PDF: https://robomechjournal.springeropen.com/track/pdf/10.1186/s40648-017-0093-3

Daisuke Hirooka, Tomomi Yamaguchi, Naomichi Furushiro, Koichi Suzumori, Takefumi Kanda. Optimization of orifice position in particle-excitation valve for proportional flow control, ROBOMECH Journal, 2017, pp. 25,