Development of Miniaturized Rubber Muscle Actuator Driven by Gas-Liquid Phase Change

2016 ◽  
Author(s):  
Tomonori Kato ◽  
Kazuki Sakuragi ◽  
Mingzhao Cheng ◽  
Ryo Kakiyama ◽  
Yuta Matsunaga ◽  
...  
Keyword(s):  
Control System ◽  
Liquid Phase ◽  
Frequency Response ◽  
Artificial Muscle ◽  
Phase Changes ◽  
Corner Frequency ◽  
Pi Control ◽  
Pneumatic Actuators ◽  
Frequency Responses ◽  
Soft Actuators

The goal of this study is to develop a miniaturized artificial muscle in which a tiny compressor can be installed. Pneumatic actuators, such as pneumatic artificial rubber muscles (PARMs), have been widely used in many industrial and robotic research applications because they are compact and lightweight. However, the compressors driving such actuators are relatively large. To solve this problem, the authors have been researching soft actuators driven by gas-liquid phase changes (GLPCs). In this study, a fixed chamber containing a constantan heater and fluorocarbon was used to generate pressure instead of a compressor. The pressure generation caused by the GLPC was confirmed, and a PARM contraction experiment was then conducted. Additionally, a PI control system was built to test the step and frequency responses of the actuator. A frequency response of up to 4.0 Hz was determined, and the corner frequency was found to be approximately 1.5 Hz. The size of the actuator was reduced by removing the chamber and installing the heater in the rubber muscle. A PARM driving experiment was conducted, and the performance of the PARM was evaluated. The miniaturized actuator consumes less power than the original actuator.

Development of Low-Cost Wearable Servo Valve Using Buckled Tube Driven by Servo Motor

2013 ◽  
Vol 393 ◽  
pp. 532-537 ◽  
Author(s):  
Abdul Nasir ◽  
Tetsuya Akagi ◽  
Shujiro Dohta ◽  
Ayumu Ono ◽  
Yusuke Masago
Keyword(s):  
Control System ◽  
Flow Rate ◽  
Position Control ◽  
Low Cost ◽  
Control Valve ◽  
Artificial Muscle ◽  
Pneumatic Actuators ◽  
Servo Valve ◽  
Precise Control ◽  
Care Systems

Recently, power assisted nursing care systems have received much attention and those researches have been done actively. In such a control system, an actuator and a control valve are mounted on the human body. Designing the system, the size and weight of the valve become serious concerns. The purpose of our study is to develop a small-sized, lightweight and low-cost servo valve for precise control using wearable pneumatic actuators. In this study, a low-cost wearable servo valve that can control the output flow rate by changing the twisted angle of the buckled tube in the servo valve is proposed and tested. The position control system of McKibben rubber artificial muscle using tested valve and embedded controller is also proposed and tested. As a result, we confirmed that the tested servo valve can control the flow rate in both supply and exhaust in an analog way. In addition, the estimated cost of the proposed valve can be reduced about 100 times cheaper (10 US Dollar) compared with the typical servo valve.

scholarly journals Improvement of dynamic characteristics of manipulator driven by a gas-liquid phase-change actuator using an antagonistic drive

2018 ◽  
Vol 192 ◽  
pp. 02015
Author(s):  
Tomonori Kato ◽  
Kenya Higashijima ◽  
Yusuke Kuradome ◽  
Kohei Noguchi ◽  
Manabu Ono
Keyword(s):  
Liquid Phase ◽  
Phase Change ◽  
Dynamic Characteristics ◽  
Force Control ◽  
Control Method ◽  
Pneumatic Actuators ◽  
Research Fields ◽  
Large Size ◽  
Heat Of Evaporation ◽  
Soft Actuators

The goal of this research is to improve the dynamic characteristics of a manipulator composed of pneumatic artificial rubber muscles driven by gas-liquid phase change. Pneumatic actuators, such as pneumatic artificial rubber muscle (PARM) or rubber bellows, have been widely used in many industrial and research fields. They have merits of being compact and lightweight. However, the large size of the compressor driving the actuator is a problem. To overcome this, the authors researched soft actuators driven by the gas-liquid phase change (GLPC) of fluorocarbon. Fluorocarbon (C5F11NO) is a substance with a relatively low boiling point (50 °C) and a low heat of evaporation (104.65 kJ/kg). The heat of evaporation of water is 2260 kJ/kg. This paper presents the overview of an actuator driven by GLPC. Then, fabrication of a manipulator using the GLPC driven PARM, and details of experiments conducted to determine manipulator characteristics are given. To improve the dynamic characteristics of the manipulator, a force control method using the antagonistic drive of two PARMs is proposed, and experiments are conducted to validate the effectiveness of the proposed method.

Experimental Validation of Nominal Model Characteristics for Pneumatic Muscle Actuator

2013 ◽  
Vol 460 ◽  
pp. 1-12 ◽  
Author(s):  
Alexander Hošovský ◽  
Kamil Židek
Keyword(s):  
Control System ◽  
Nonlinear Differential Equations ◽  
Model Performance ◽  
Weight Ratio ◽  
Open Loop ◽  
Artificial Muscles ◽  
Pneumatic Actuators ◽  
Intelligent Control System ◽  
Pneumatic Artificial Muscles ◽  
The One

Pneumatic artificial muscles belong to a category of nonconventional pneumatic actuators that are distinctive for their high power/weight ratio, simple construction and low price and maintenance costs. As such, pneumatic artificial muscles represent an alternative type of pneumatic actuator that could replace the traditional ones in certain applications. Due to their specific construction, PAM-based systems have nonlinear characteristics which make it more difficult to design a control system with good performance. In the paper, a gray-box model (basically analytical but with certain experimental parts) of the one degree-of-freedom PAM-based actuator is derived. This model interconnects the description of pneumatic and mechanical part of the system through a set of several nonlinear differential equations and its main purpose is the design of intelligent control system in simulation environment. The model is validated in both open-loop and closed-loop mode using the measurements on real plant and the results confirm that model performance is in good agreement with the performance of real actuator.

Auto-Tuning Tub-Level Control of Blender in Hydraulic Fracturing

2016 ◽  
Author(s):  
Zheng Chen ◽  
Leslie Cargill ◽  
Brent Naizer
Keyword(s):  
Control System ◽  
Hydraulic Fracturing ◽  
Oil And Gas ◽  
Pi Control ◽  
Automation System ◽  
Control Performance ◽  
Level Control ◽  
Relay Feedback ◽  
System Parameters ◽  
Auto Tuning

Hydraulic fracturing is one of the key technologies for producing shale oil and gas. During hydraulic fracturing, a blender is used to mix sand with water and chemicals to obtain a fluidic mixture that will be pumped down a well to frack rocks. In order to achieve high-quality fracturing during a job, the blender needs to maintain its tub level as well as the density of the fluidic mixture. In this paper, an auto-tuning proportional-integral (PI) control is developed for the blender automation system to maintain the tub level of its fluidic mixture. The control system adopts a single-loop PI with gains that can be auto-tuned during a job. A relay feedback test is conducted for auto-tuning the PI gains online. The auto-tuning PI control has been successfully tested in a blender simulator. Experimental results have shown that the control performance was improved after auto-tuning and that the control system was adaptive to variation in system parameters.

Multiple Inputs-Single Accumulated Output Mechanism for Soft Linear Actuators

2018 ◽  
Vol 11 (1) ◽  
Author(s):  
Kyeong Ho Cho ◽  
Ho Moon Kim ◽  
Youngeun Kim ◽  
Sang Yul Yang ◽  
Hyouk Ryeol Choi
Keyword(s):  
Artificial Muscle ◽  
Operating Mode ◽  
Robotic Arm ◽  
Soft Actuator ◽  
Wearable Robots ◽  
Working Principle ◽  
Linear Actuators ◽  
Soft Actuators ◽  
Muscle Actuators ◽  
Further Development

Soft linear actuators (SLAs) such as shape memory alloy (SMA) wires, pneumatic soft actuators, dielectric elastomer actuator, and twisted and coiled soft actuator (TCA) called artificial muscle actuators in general, have many advantages over the conventional actuators. SLAs can realize innovative robotic technologies like soft robots, wearable robots, and bionic arms in the future, but further development is still needed in real applications because most SLAs do not provide large displacement or force as needed. This paper presents a novel mechanism supplementing SLAs by accumulating the displacement of multiple SLAs. It adopts the principle of differential gears in reverse. Since the input units of the mechanism are extensible, more displacement can be accumulated by increasing the number of the input units as many as needed. The mechanism is basically used to accumulate displacements, but can be used to accumulate forces by changing its operating mode. This paper introduces the design and working principle of the mechanism and validates its operation experimentally. In addition, the mechanism is implemented on a robotic arm and its effectiveness is confirmed.

scholarly journals Femtosecond diffraction studies of solid and liquid phase changes in shock-compressed bismuth

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
M. G. Gorman ◽  
A. L. Coleman ◽  
R. Briggs ◽  
R. S. McWilliams ◽  
D. McGonegle ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Phase Changes
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