Rubber Actuator Research Articles

Adaptive Nonlinear Sensorless Control for an Uncertain Miniature Pneumatic Curling Rubber Actuator Using Passivity and Robust Right Coprime Factorization

In this brief, an adaptive nonlinear sensorless control for an uncertain miniature pneumatic curling rubber actuator is considered using passivity and the robust right coprime factorization approach. Specially, based on the robust right coprime factorization approach, robust stability is guaranteed and passivity is realized simultaneously. Then, the adaptive control system is designed for tracking performance. Support vector regression is proposed to estimate the output for avoiding the use of a sensor. Finally, the experimental setup is shown and the experimental results are provided to show the effectiveness of the proposed scheme.

自立型空圧３腕ロボットの試作

Pneumatic rubber actuators have merits such as high compliance, simplicity of miniaturization and light weight whereas they also have demerits such as a need for compressors and air tubes. We have been developing compressor-less pneumatic actuators which are driven by reversible chemical reaction instead of compressors. This actuators can generate enough pressure of 0.5 MPaG to move pneumatic actuators. In this paper, we discuss about the untethered 3 arms robot which has this compressor-less pneumatic actuator inside its body. This robot has three bellows hands and can actuate them up and down. As experimental results, the arms were rose in 16 seconds and declined in 34 seconds.

1A1-B03 高機能化を目的とする表面微細弁構造を搭載したプラスティックフィルム製ソフトアクチュエータの提案

Recent years, the assist-equipment for the purpose of the living support and nursing care have been developed. That equipment usually used rubber actuators. In conventional researches, pneumatic plastic-film soft actuators are proposed. It is considered that pneumatic plastic-film soft actuator is effective to use for assist-equipment from advantages which are lightweight, flexibility and driving at low pressure. However, this actuator does not have sufficient characteristics in order to use for the assist-equipment. This paper focused on improvement of the responsiveness as one method of solving this problem. The principle of the micro-valve structure for plastic-film soft actuator is proposed, and basic experiment using the actuator is described.

1P1-T01 空気圧ソフトアクチュエータを用いた伸長型3自由度湾曲モデルの研究 : 繊維強化型円筒ラバーアクチュエータの理論式の構築と静特性の評価

Pneumatic actuators have a low stiffness and low cost, which enables disposability of system components. They are highly useful for medical use in terms of infection prevention and easiness to compatible with biological systems. We designed a pneumatic soft actuator, called "fiber-reinforced cylindrical rubber actuator (henceforth FCRA)", and manufactured an extension type 3-degrees-of-freedom bending model by combining the three FCRAs. We derived the theoretical formula used to describe and evaluate static properties of our model, and then validated it through various actuation experiments for extension and bending movements. As a result, our theory has successfully explained all the experimental results. We are currently planning to apply the proposed model to the tip part of colonoscopes.

A study on a soft microgripper using MEMS-based divided electrode type flexible electro-rheological valves

This paper presents a novel soft microgripper whose finger consists of a hydraulic rubber actuator and an ER valve to manipulate tools and objects on an in-pipe working micromachine flexibly. The microgripper can also manipulate fragile objects such as biological cells safely. The electro-rheological fluid (ERF) flow into the hydraulic rubber actuator is controlled by the ER valve through its apparent viscosity increase due to the applied electric field. The ER valve in this study is a proposed divided electrode type flexible ER microvalve (DE-FERV) which has axially divided parallel plate electrode pairs in a flexible tube and has high bending flexibility and high axial rigidity. The hydraulic rubber actuator has plural walls inside to restrict the radial expansion and axially extends by the inner pressure increase. The microfinger is composed of a hydraulic rubber actuator and a DE-FERV on the side and bends by the extension of the hydraulic rubber actuator. To miniaturize the soft microgripper, MEMS fabrication process was developed and applied. A 2.8mm long DE-FERV was designed and successfully fabricated with the electrode total length of 2.8mm, width of 1mm, and gap height of 0.1mm. The pressure change ratio up to 6.3 was shown experimentally. A 3mm long hydraulic rubber actuator was fabricated by molding process and attached to the DE-FERV. Based on air pressure tests, it was estimated that the microgripper will be able to grasp 0.4mm wide objects with a grasping force 2.4mN.

Development of femoral bone fracture model simulating muscular contraction force by pneumatic rubber actuator.

In femoral fracture reduction, orthopedic surgeons must pull distal bone fragments with great traction force and return them to their correct positions, by referring to 2D-fluoroscopic images. Since this method is physically burdensome, the introduction of robotic assistance is desirable. While such robots have been developed, adequate control methods have not yet been established because of the lack of experimental data. It is difficult to obtain accurate data using cadavers or animals because they are different from the living human body's muscle characteristics and anatomy. Therefore, an experimental model for simulating human femoral characteristics is required. In this research, human muscles are reproduced using a McKibben-type pneumatic rubber actuator (artificial muscle) to develop a model that simulates typical femur muscles using artificial muscles.

Simulations of Two Patterns Fiber Weaves Reinforced in Rubber Actuator

Over recent years, studies on soft mechanism are rapidly being paid to attention especially in pneumatic actuator field. Good actuator should be able to provide sufficient force and flexibility in movement, hence bending motion is vital criteria needed in soft robotic actuation. In this paper, a solution to soft bending pneumatic actuator is proposed in which several patterns fiber weave designs are introduced. The objectives of the simulations is to investigate which weave patterns combination of fiber reinforced actuator models yields the best bending characteristics and its relation to the contraction or extension characteristics shown by single weave pattern actuator models. From the results, when two patterns of fiber weave are attached together to form a sleeve, significant bending were obtained from most of the models simulated. Large bending resulted from combined two patterns fiber weave models are achieved when maximum contraction and extension characteristics exhibit by both fiber weave patterns.

ラバーアクチュエータのロボット医療分野への応用：心臓補助装置の研究動向

ラバーアクチュエータのロボット医療分野への応用：心臓補助装置の研究動向

2203 高周波交流圧力源を用いた多自由度マイクロアクチュエータシステムの開発(センサ・アクチュエータ(2))

This paper presents a multi-DOF (degrees of freedom) microactuator system using a high frequency alternating-pressure source. The alternating flow from the pressure source is rectified by the synchronized active valves to drive plural hydraulic microactuators. To increase the position resolution and downsize the pressure source, the driving frequency was increased using high response piezoelectric elements. Thin piezoelectric valves and an alternating-pressure source were proposed and developed using piezoelectric bimorph disks. In addition, a 10 mm long bending rubber actuator with two chambers was fabricated and a system was constructed. The bending motion of the actuator was experimentally clarified.

Vibration Analysis and Control of an Active Power-Train Mount System

In order to improve the property of automotive power-train vibration isolation, reduce the vibration that is transmitted by the power-train to the vehicle chassis, we adopt an active control mount (ACM) which consists of elastic rubber and piezoelectric stack actuator in the system. A hydraulic mechanism is used in the ACM to achieve higher displacements. Through the analysis of the property of the rubber and piezoelectric stack actuator, a mechanical model of the active vibration isolation system with the active mounts is established. An optimal control algorithm is presented for engine vibration isolation system, the controller is designed according to linear quadratic regulator (LQR) theory, the linear quadratic performance index is composed of the vertical acceleration, pitching angular acceleration, and rolling angular acceleration of the chassis and the control signals. Simulation results show that active control system of ACM, effect in reducing body vibration than the passive system is obvious.

Active Control for Power-Train Vibration of Automotive Using Active Mounts

In this work, a new active mount featuring piezostack actuators and a rubber element is proposed and applied to a vibration control system. After describing the configuration and operating principle of the proposed mount, an appropriate rubber element and appropriate piezostacks are designed. Through the analysis of the property of the rubber and piezoelectric stack actuator, a mechanical model of the active vibration isolation system with the active mounts is established. An optimal control algorithm is presented for engine vibration isolation system. the controller is designed according to linear quadratic regulator (LQR) theory. Simulation shows the active system has a better consequence in reducing the vibration of the chassis significantly with respect to the ACM and the optimal control than that in the passive system.

A Bio-Inspired Robot Using Electro-Conjugate Fluid

Electro-Conjugate Fluid (ECF) is a kind of functional fluid that produces a jet flow (ECF jet) when subjected to high DC voltage. A strong ECF jet is known to be generated in a nonuniform electric field, for example, a field with a pair of needle and ring electrodes. This study introduces the ECF jet in developing a novel bio-inspired robot. We first propose the concept of a robot driven by an ECF jet. The robot is mainly composed of ECF jet generators (a micro fluid pressure source), fiber-reinforced rubber actuators, a built-in spring actuator, and an ECF tank. We next investigate the characteristics of the ECF jet generator, the fiberreinforced rubber actuator, and the built-in spring actuator. As a result, we confirmed that the maximum pressure and flow rate of the ECF jet generator are 32.0 kPa and 27.0 ml/min, respectively, and that the actuators could be driven by the ECF jet. We then developed a bio-inspired robot and demonstrated that the robot could move in a 14 mm diameter acrylic half pipe with 0.6 mm/s, and in a 14 mm diameter acrylic pipe with 0.5 mm/s. The robot is 300 mm long with a mass of 26 g.

1P1-M03 大腸内視鏡挿入支援用アクチュエータのフィンの改良とファントム実験(医療ロボティクス・メカトロニクス(1))

1P1-M03 大腸内視鏡挿入支援用アクチュエータのフィンの改良とファントム実験(医療ロボティクス・メカトロニクス(1))

Miniature Pneumatic Curling Rubber Actuator Generating Bidirectional Motion with One Air-Supply Tube

Soft actuators driven by pneumatic pressure are promising actuators for mechanical systems in medical, biological, agriculture, welfare fields and so on, because they can ensure high safety for fragile objects from their low mechanical impedance. In this study, a new rubber pneumatic actuator made from silicone rubber was developed. Composed of one chamber and one air-supply tube, it can generate curling motion in two directions by using positive and negative pneumatic pressure. The rubber actuator, for generating bidirectional motion, was designed to achieve an efficient shape by nonlinear finite element method analysis, and was fabricated by a molding and rubber bonding process using excimer light. The fabricated actuator was able to generate curling motion in two directions successfully. The displacement and force characteristics of the actuator were measured by using a motion capture system and a load cell. As an example application of the actuator, a robotic soft hand with three actuators was constructed and its effectiveness was confirmed by experiments.

大腸内視鏡挿入支援を目指したラバーチューブアクチュエータの設計と基礎駆動特性

Colonoscopy is an important medical action to detect disorders like colon cancer. However generally it is difficult to insert a scope into the colon, because the colon is flexible and complex shape. This study aims at development of an actuator which can add propelling ability to a colonoscope. We focus on rubber pneumatic actuators, because advantages of them, for example, high compliance, low cost, water proof, and so on, agree with the required properties of medical devices. In this paper, we design a novel rubber actuator consisting of three air chambers by nonlinear FEM (finite element method) and fabricate the actuator employing the design by extrusion molding method. Basic characteristics of the actuator are clarified by a motion capture system, and functional motion leading assisting colonoscope insertion is observed. Actually using dummy endoscope, transportation ability by the actuators is confirmed experimentally and insertion experiments into a large intestine phantom are conducted.

2A2-C13 水圧人工筋で駆動する柔軟関節を持つ水中ロボットアームの開発

2A2-C13 水圧人工筋で駆動する柔軟関節を持つ水中ロボットアームの開発

1A1-D25 福祉介護用高機能靴の開発

In recent years, the number of falling accidents of elderly pedestrians tends to increase. One of these causes is a change of the center of gravity position at sole. This reason is that the elderly people are difficult to balance the center of gravity position by decline of their leg strength. Therefore, they become easy to fall. Thus, in order to solve these problems, developments of new products to prevent fall motion are desired. In this study, we propose high performance shoes to enable stable walking. That is to say, in order to develop the shoes, we use the Sponge Core Soft Rubber Actuator (SCSRA) as the pneumatic element. The SCSRA can control the stiffness with change of internal pressure of the element. In this paper, we use the actuator as an insole of shoes. Moreover, the effectiveness of the proposed shoes is indicated through some experimental results.

2P1-B10 磁気機能性流体を用いた円筒型ラバーアクチュエータの応答特性

The purpose of my work was to develop cylindrical rubber actuators containing a magneto-rheological fluid. In this paper, response properties of a rubber actuator using a permanent magnet were presented. We developed two different rubber actuators. First type of the rubber actuator consists of an isoparaffin-based magnetic fluid and a silicon rubber. Second type of the rubber actuator consists of a polyalphaolefin-based magnetorheological fluid and a silicon rubber. A Laser displacement sensor is employed to find the relationships between the magnetic field and the displacement of rubber actuator. As a result, the responsibility of rubber actuator containing an isoparaffin-based magnetic fluid indicated the best performance.

2G1-4 空気圧ソフトゴムアクチュエータを用いた高機能中敷きの開発(OS4:ソフトアクチュエータを用いた医療福祉機器の開発,オーガナイズドセッション)

In recent years, it is reported that the number of falling accidents of elderly pedestrians tends to increase. As one of this cause, it is considered that the center of gravity position with sole is changed. This is because that the elderly people are difficult to balance the center of gravity position by decline of their leg strength. Therefore, they become easy to fall. Thus, in order to solve these problems, developments of new products to prevent fall motion are desired. In this study, we propose high performance shoes to enable stable walking. That is to say, in order to develop the shoes, we use the Sponge Core Soft Rubber Actuator (SCSRA) as the pneumatic element. The SCSRA can control the stiffness with change of internal pressure of the element. Therefore this actuator can be used as an insole of the shoes. In this paper, the effectiveness of the proposed shoes is cleared through some experimental results.

2G1-1 筋電制御によるゴム人工筋を用いたがん骨転移患者の寝返り支援コルセットの開発(OS4:ソフトアクチュエータを用いた医療福祉機器の開発,オーガナイズドセッション)

2G1-1 筋電制御によるゴム人工筋を用いたがん骨転移患者の寝返り支援コルセットの開発(OS4:ソフトアクチュエータを用いた医療福祉機器の開発,オーガナイズドセッション)