Daisuke Hirooka

Development of bending soft actuator with different braided angles

In recent years, many researchers have been focusing on the different novel techniques in designing pneumatic soft actuator that can produce bending motion. This paper presents a novel soft actuator design; a combination of different braided angles of artificial muscle applied on a single chamber soft actuator to produce bending motion. The actuator construction is based on the theory of contraction and extension of artificial muscle. It comprises of fiber-reinforced inside silicone rubber and is capable to create one-sided bending motion. Analysis of nonlinear finite element method is conducted to predict the direction and bending angles of the actuator before a prototype of actuator is fabricated. Based on the results, the developed soft actuator can realize bending motion after standard pressure driving experiment is executed.

Continuous air control using particle excitation valve

In this paper, we report a new prototype of the particle excitation flow control valve to control flow rate continuously. The purpose of this study is the development of the valve that can precisely control pneumatic cylinders. We reported this flow control valve principle in the previous paper and concluded the diameter of orifice is an important parameter for flow rate change. In this report, we have designed a new prototype for the purpose of high controllability. We have measured flow rate characteristics and confirmed the conditions necessary for continuous adjustment of flow quantity by experiment.

Experimental analysis on pneumatic flow control valve driven by PZT vibrator

Recently, pneumatic actuators are widely used in the automation machine equipments because they are simple, lightweight, and highly compliant. Valve that can realize a continuous flowing quantity control is necessary to control air actuators precisely, while in general, such a valve is large. This study aims at the development of a new flow control valve that has a lightweight and simple structure and uses piezoelectric oscillator which is driven at resonance mode and it can control flow-rate by controlling the amplitude of the particles excitation. The flow control valve in this report is 10 mm in diameter and 9 mm in height. We had already achieved ON/OFF control of large flowing quantity with the valve. In this report, we research dynamic characteristics and properties under high air pressure. As the results of experiments, we found that the valve response time is 29 ms and the valve vibration property changed under air pressure. We confirmed its mechanism and found condition to control flow rate continuously.

Pneumatic flow control valve using particle excitation by PZT transducer

This paper reports a flow control valve for pneumatic actuators. This flow control valve has a lightweight and simple structure using particle excitation by PZT transducer, which is driven at resonance mode and it can be used as a variable speed controller for pneumatic actuators. A PZT transducer has been used for controlling flow rate in this study. The flow control valve in this report consists of an orifice plate, a PZT transducer which is fixed on the orifice plate with the bolt, and the iron particles of 0.8mm diameter. From the experiments of flowing quantity evaluation, this flow control valve achieves a maximum flow rate of 62.65 L/min under applying voltage of 79.9 Vp-p and air pressure of 0.70 MPa. The results show that the ratio of the flow capacity /valve weight is about ten times larger than that of typical commercial valves.

Highly responsive and stable flow control valve using a PZT transducer

Pneumatic actuators are widely used because they are lightweight and inexpensive. However, highly controllable devices for pneumatic actuators generally have large volume and low response and are heavy. We have developed the flow control valves that have highly controllable using PZT elements. These control valves can downsize the control valve with high response. Using a PZT transducer, we introduced a new mechanism of the control valve for stable continuous flow rate. In this report, we proposed a new mechanism to realize stable continuous flow with a PZT transducer. We designed prototype using a bolt-clamped Langevin transducer (BLT) and show the characteristics of the valve.

Small size pneumatic valve for smooth flow control using PZT vibrator

Pneumatic actuators have the potential to be downsized because they have simple structure. However, many control devices that can control pneumatic actuators continuously have large volume and weight. We have designed a flow-control valve driven by PZT vibrator. This control valve has small volume and low weight, and it can control air flow smoothly. This valve is suited to control small pneumatic actuators. The flow control valve that we propose uses resonance vibration with a PZT vibrator. The valve consists of an orifice plate, a PZT vibrator and iron particles that work as the poppet. From experimental flow quantity evaluation, this control valve controls air flow smoothly with low hysteresis at a large flow rate. In addition, this flow control valve achieves a maximum flow rate of 65 L/min under air pressure of 0.70 MPa. The results show that the valve has high controllability and can control a relatively large flow rate compared to its weight and size.