Pneumatic Balloon Actuator Research Articles

Openable Double‐Microtube Structure Driven by Pneumatic Balloon Actuator Arrays for Tubular Organ‐on‐a‐Chip

Microfluidic platforms have revolutionized research in biomedical engineering, enabling efficient and controlled experimentation. Here, we present a novel microfluidic device, the double‐microtube, which offers parallel flow of different fluids. The device is fabricated by transforming a flat structure on a substrate using pneumatic balloon actuator arrays. The inner and outer tubes of the device can be independently controlled, allowing for individual opening and closing of each tubular structure. The inner and outer tubes have diameters of 1 mm and 3 mm, respectively. The device has been successfully tested for cell culture, showcasing its potential application for tubular organ‐on‐a‐chip studies, such as blood vessels and the small intestine. The presented double‐microtube structure promises a new level of control for microfluidic studies, offering exciting opportunities for researchers in the field of biomedical engineering. © 2024 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.

Active tactile sensing of small insect force by a soft microfinger toward microfinger-insect interactions

Human–robot interaction technology has contributed to improving sociality for humanoid robots. At scales far from human scales, a microrobot can interact with an environment in a small world. Microsensors have been applied to measurement of forces by flying or walking insects. Meanwhile, most previous works focused on the measurement of the behavior of insects. Here, we propose microrobot-insect interactions by soft microfingers integrated with artificial muscle actuators and tactile sensors, which has been developed for a haptic teleoperation robot system. A soft pneumatic balloon actuator acts as the artificial muscle, and a flexible strain sensor using a liquid metal provides tactile sensing. Force interaction between a pill bug and the microfinger could be accomplished. The microfinger (12 mm × 3 mm × 490 μm) can move and touch an insect, and it can detect reaction force from an insect. The measured reaction force from the legs of a pill bug as a representative insect was less than 10 mN. This paper presents a microfinger as an end effector for the active sensing of reaction force from a small insect. We anticipate that our results will lead to further evaluation of small living things as well as technology development for human–environment interaction.

Structural Reinforcement Effect of a Flexible Strain Sensor Integrated with Pneumatic Balloon Actuators for Soft Microrobot Fingers.

Motion capture of a robot and tactile sensing for a robot require sensors. Strain sensors are used to detect bending deformation of the robot finger and to sense the force from an object. It is important to introduce sensors in effective combination with actuators without affecting the original performance of the robot. We are interested in the improvement of flexible strain sensors integrated into soft microrobot fingers using a pneumatic balloon actuator (PBA). A strain sensor using a microchannel filled with liquid metal was developed for soft PBAs by considering the compatibility of sensors and actuators. Inflatable deformation generated by PBAs, however, was found to affect sensor characteristics. This paper presents structural reinforcement of a liquid metal-based sensor to solve this problem. Parylene C film was deposited into a microchannel to reinforce its structure against the inflatable deformation caused by a PBA. Parylene C deposition into a microchannel suppressed the interference of inflatable deformation. The proposed method enables the effective combination of soft PBAs and a flexible liquid metal strain sensor for use in microrobot fingers.

Soft Hybrid Suction Cup Capable of Sticking to Various Objects and Environments

A universal suction cup that can stick to various objects expands the areas in which robots can work. However, the size, shape, and surface roughness of objects to which conventional suction cups can stick are limited. To overcome this challenge, we propose a new hybrid suction cup structure that uses the adhesive force of sticky gel and the suction force of negative pressure. In addition, a flexible and thin pneumatic balloon actuator with a check valve function is installed in the interior, enabling the controllable detachment from objects. The prototype has an outer diameter of 55 mm, a weight of 18.8 g, and generates an adsorption force of 80 N in the vertical direction and 60 N in the shear direction on porous walls where conventional suction cups struggle to adsorb. We confirmed that parts smaller than the suction cup and fragile potato chips are adsorbed by the prototype. Finally, the effectiveness of the proposed method is verified through experiments in which a drone with the prototypes can be attached to and detached from concrete walls and ceilings while flying; the possibility of adsorption to dusty and wet plates is discussed.

Flexible Temperature Sensor Integrated with Soft Pneumatic Microactuators for Functional Microfingers

The integration of a flexible temperature sensor with a soft microactuator (a pneumatic balloon actuator) for a functional microfinger is presented herein. A sensor integrated with a microactuator can actively approach a target for contact detection when a distance exists from the target or when the target moves. This paper presents a microfinger with temperature sensing functionality. Moreover, thermocouples, which detect temperature based on the Seebeck effect, are designed for use as flexible temperature sensors. Thermocouples are formed by a pair of dissimilar metals or alloys, such as copper and constantan. Thin-film metals or alloys are patterned and integrated in the microfinger. Two typical thermocouples (K-type and T-type) are designed in this study. A 2.0 mm × 2.0 mm sensing area is designed on the microfinger (3.0 mm × 12 mm × 400 μm). Characterization indicates that the output voltage of the sensor is proportional to temperature, as designed. It is important to guarantee the performance of the sensor against actuation effects. Therefore, in addition to the fundamental characterization of the temperature sensors, the effect of bending deformation on the characteristics of the temperature sensors is examined with a repeated bending test consisting of 1000 cycles.

Morphological Transformation between Flat and Tube Structures by Coordinated Motions of Soft Pneumatic Microactuators

Microactuators are the most distinctive and challenging microdevices among micro electromechanical systems (MEMS) relative to microsensors or electronic circuits. Soft and flexible microactuators have been achieved by introducing polymers as structural materials in addition to conventional materials. Expanding the application of MEMS to the biomedical field requires particular features, such as softness and small devices. It is important to address small and fragile biological objects while satisfying the demand for minimally invasive medicine. Both MEMS and biomedical applications require three-dimensional microstructures for higher-order functions. In general, microactuators are limited to simple motions such as bending. Our group has developed an openable artificial small intestinal tract system. An array of pneumatic balloon actuators (PBAs) transforms a flat structure into a tube structure representing the small intestine. Coordination of the bending motions of the PBAs enables the formation of a three-dimensional tube structure. Each PBA is 400 μm × 1800 μm × 100 μm. The diameter of the tube structure is 1 mm. Additional higher-order functions of the artificial small intestine, such as peristaltic motion, are currently of interest for us. This paper describes the morphological transformation of a soft microstructure and further potential possibilities of coordinated motions of soft microactuators.

Pneumatic balloon actuator control through integrated microvalves using thermally responsive fluids

This paper shows the integration of a valve into the pressure supply channel for a pneumatic balloon actuator (PBA). We employed a microvalve using a thermally responsive fluid as the valve that integrates with the PBA. Aqueous Pluronic® F127 solutions are thermally responsive fluids that change their viscosity as a function of temperature. The viscosity of a Pluronic® F127 solution can be controlled by a heater integrated into the supply channel to close and open the channel. In this paper we also show the measured pressure resistance of the microvalve and the demonstration of a PBA integrated with a microvalve. The integration of a valve into the pneumatic actuator allows designing compact pneumatic actuator systems.

Integration of optical waveguide on pneumatic balloon actuator for flexible scanner in endoscopic imaging diagnosis applications

This paper reports a flexible scanner consisting of a scanning actuator and optical waveguides for medical imaging applications such as endoscopic fluorescence imaging diagnosis. The 0.3-mm-thick and 5-mm-wide functional scanner was designed to be smaller enough than the 10 mm-diameter of channel of endoscope. The proposed device can be used to introduce an excitation light into the abdominal cavity or digestive tract. A pneumatic balloon actuator (PBA) consisting of polydimethylsiloxane (PDMS) is used as the scanning actuator for the scanner in consideration of its small, soft, and safe features. The SU-8 optical waveguides with high refractive index (nSU-8 = 1.575) are integrated onto the PBA structure made of PDMS with a lower refractive index (nPDMS = 1.405). Excitation light at a wavelength of 405 nm is transmitted through an optical fiber to the SU-8 waveguides. The outgoing light from the waveguide can be scanned by the bending motion of the PBA. The waveguide functions as a detector as well. Our developed device has successfully scanned, excited, and detected light from fluorescence beads at a wavelength of 540 nm distributed in a pseudo-tissue.

Implementation of soft microfingers for a hMSC aggregate manipulation system.

This paper describes a pneumatic balloon actuator (PBA) composed of polydimethylsiloxane (PDMS) for cellular aggregate manipulation. We evaluated the ability of the microdevice to manipulate a tiny and sensitive cellular aggregate without causing serious damage. We used human mesenchymal stem cells (hMSCs) for the cellular aggregate. We describe the design, fabrication, characterization and operation of the soft microfingers to pinch and release a spherical hMSC aggregate (φ200 μm), and we employed a PBA to serve as an artificial muscle to drive the microfingers. A design of the microfingers in terms of dimensions, generated force and contact conditions was accomplished. The designed dimensions of a single finger were 560 μm×900 μm. In summary, we demonstrate the utility of the surface modification of a fingertip for pinching and releasing a cellular aggregate and describe a manipulation system that was constructed to drive and control the microfingers. The implemented manipulation system, which is composed of microfingers and a positioning mechanism, was tested and verified in a series of operations.

Model Predictive Control for Tendon-Driven Balloon Actuator under Constraints on Simulation

Many pneumatic actuators have been developed in order to be lightweight with high output for decreasing impact force. So far, a pneumatic tendon-driven balloon actuator (balloon actuator) which is compact and lightweight has been developed for a robot hand and a rehabilitation device. However, for pneumatic actuator, it is difficult to maintain exact control because these actuators have constraints. For this study, we developed a stroke control system for a balloon actuator using a constrained model predictive control (MPC) scheme that can consider constraints of the plant output. As described in this paper, we compared and evaluated the control performance using MPC and PID.

Pneumatic microfinger with balloon fins for linear motion using 3D printed molds

Polymer-based pneumatic balloon actuators consisting of novel trapezoidal vertical microballoon fins were fabricated by three-dimensional (3D) printed molds and validated experimentally. The introduction of 3D printed molds for pneumatic actuation provides additional freedom in the design of actuators, removing the limitation of extruded 2D shapes that is present with conventional microfabrication. Whereas conventional balloon actuators exhibit nonlinear response to applied pressure, the presence of balloon fins with 100s-μm width was shown to produce a linear change in bend angle with the injection of pressurized air. The balloon fins also mitigate stress concentrations that can lead to material failure. Static bending (exceeding 80° bend angle) and the mechanical force of the fabricated microfingers were tested and compared with analytical models. The expanded design space permitted by 3D printing allows actuator designs to achieve a given deflection with less stress in the material as compared to planar designs. Feasibility of this design flexibility and fast prototyping enabled by the 3D printed molding process was demonstrated by fabricating and testing various designs of microfingers. When grouped, the microfingers with balloon fins can successfully accomplish complex object transfer tasks (i.e., multi-directional actuation with independently controlled displacement).

An openable artificial intestinal tract system for the in vitro evaluation of medicines

AbstractIn vitro drug screening systems for pharmacological targets have been studied as substitutes for whole-animal experiments. Cultured cells or tissues provide promising substitution models when coupled with technological innovations in micro total analysis systems. In this study, we focus on an intestinal drug absorption assay, as the oral route is most frequently used for drug administration. Pharmacological studies have reported the development of artificial vessels that include tubular structures. However, it is difficult to observe the insides of these tubes in situ. To address this problem, we developed a micro-device that uses a pneumatic balloon actuator (PBA) to open and close an artificial intestinal tract. A human colon carcinoma cell line (Caco-2) was cultivated on the flat surface of the micro-device for 7 days to form the inner cellular layer of an artificial intestinal tract with which to evaluate drug transport. The artificial intestinal tract was completely actuated from a flat plate to a circular tube via a PBA with a pressure of 65 kPa, and drugs were perfused at a flow rate of 0.05 mL min−1 into the tubular artificial intestinal tract for 1 h. Using the openable artificial intestinal tract, the in vitro absorption of calcein and Texas Red were successfully estimated as models of hydrophilic and hydrophobic drugs, respectively. The artificial intestinal tract enables the effective evaluation of the in vitro intestinal absorption of drug candidates and contributes to the reduction of costs incurred during the initial stage of drug development.

New Pneumatic Rubber Leg Mechanism for Omnidirectional Locomotion

This paper describes a new pneumatic rubber leg mechanism for omnidirectional locomotion. The new mechanism was adopted from a pneumatic balloon actuator where translation and bending motions are produced as a result of balloon deformation. It was constructed using five chambers: one on the top and centered over four bottom chambers arranged in a square. Several possible designs were simulated to achieve the optimal design using a non-linear finite element analysis that considered the design parameters and the geometrical and material non-linearity of the elements. Prototyping was then performed using a rapid and efficient silicone rubber molding fabrication process based on computer-aided design and manufacturing. The experimental results were in good agreement with the analytical results. In conclusion, we have established a new rubber leg mechanism with a high degree of freedom to realize omnidirectional locomotion for a soft robot base, delicate object conveyance, and / or microscope stage applications.

3P1-Q01 圧力駆動バルーンアクチュエータを利用したマイクロフィンガーによる培養細胞の把持・解放操作(MEMSとナノテクノロジー)

This paper proposes a micro manipulation with microfongers for three dimensional cell cultures such as a cellular aggregate. We recently reported a catcher device to trap and transport a cellular aggregate by using fluidic control. In this work, we reports microfingers to pinch and release a spherical cellular aggregate (φ200 μm). We have studied pneumatic balloon actuator (PBA) which has small, soft and safe characters. These are suitable for biomechanical appreciations. This paper will show design, fabrication and characterization of microfingers and demonstrate its operation. We also show that surface treatment of fingertip is of significance. A series of operation with a real cellular aggregate by using novel microfinger will be successfully demonstrated.

W221003 柔らかなマイクロマシンのバイオメディカル応用([W22100]マイクロ・ナノ工学部門企画,マイクロ・ナノ医療デバイス)

Soft structure and flexible motion have become important to handle living organisms in biotechnology and medical applications. These features are expected to provide precise tools suitable for manipulation of tiny or fragile living organisms in biotechnology and advanced medical tools for minimally invasive medicine. We have studied pneumatic balloon actuator "PBA" which is suitable for biomedical application because of its small, soft and safe features. For example, PBA-based medical tool was applied to a retractor for spacing in front of the endoscope at our early stage. As a very recent result of PBA-based tool, study on manipulator for cellular aggregate (φ200μm) will be reported.

Predictive Functional Control with Disturbance Observer for Tendon-Driven Balloon Actuator

In recent years, Japanese society has been aging, engendering a labor shortage of young workers. Robots are therefore expected to perform tasks such as rehabilitation, nursing elderly people, and day-to-day work support for elderly people. The pneumatic balloon actuator is a rubber artificial muscle developed for use in a robot hand in such environments. This actuator has a long stroke and a high power-to-weight ratio compared with the present pneumatic artificial muscle. Moreover, the dynamic characteristics of this actuator resemble those of human muscle. This study evaluated characteristics of force control of balloon actuator using a predictive functional control (PFC) system with disturbance observer. The predictive functional control is a model-based predictive control (MPC) scheme that predicts the future outputs of the actual plants over the prediction horizon and computes the control effort over the control horizon at every sampling instance. For this study, a 1-link finger system using a pneumatic balloon actuator is developed. Then experiments of PFC control with disturbance observer are performed. These experiments demonstrate the feasibility of its control of a pneumatic balloon actuator for a robot hand. Keywords—Disturbance observer, Pneumatic balloon, Predictive functional control, Rubber artificial muscle.

2A1-E07 外乱オブザーバ併用型予測機能制御に基づくバルーン型腱駆動アクチュエータのストローク制御(アクチュエータの機構と制御(1))

In recent years, Japanese society has been aging, engendering a labor shortage of young workers. Robots are therefore expected to be useful to perform tasks such as day-to-day work support for elderly people. Consequently, a tendon-driven balloon actuator has been developed for a robot hand in such environments. This study evaluated stroke control characteristics of a balloon actuator using a predictive functional control (PFC) system. Predictive functional control, a model based on predictive control (MPC) schemes, predicts the future outputs of the actual plant over the prediction horizon and computes the control effort over the control horizon at every sampling instance. In this paper, performances of PFC control with disturbance observer of 1-link finger using pneumatic balloon actuator are reported.

Implantable pneumatically actuated microsystem for renal pressure-mediated transfection in mice

In vivo transfection is an important technique used in biological research and drug therapy development. Previously, we developed a renal pressure-mediated transfection method performed by pressing a kidney after an intravenous injection of naked nucleic acids. Although this is a useful method because of its safety and wide range of applications, an innovative approach for performing this method without repeatedly cutting open the abdomen is required. In this study, we developed an implantable microsystem fabricated by Micro-Electro-Mechanical Systems (MEMS) technologies for renal pressure-mediated transfection. The system consists of a polydimethylsiloxane pneumatic balloon actuator (PBA) used as an actuator to press the target kidney. The PBA of the implanted microsystem can be actuated without opening the abdomen by applying air pressure from outside the body to the pressure-supplying port via a needle. We successfully performed renal pressure-mediated transfection using the newly developed system when the implanted system was activated at 60kPa for 10s. This is the first report of an implantable MEMS-based microsystem that demonstrates in vivo transfection to a kidney using naked plasmid DNA.

Development and control of a multifingered robotic hand using a pneumatic tendon-driven actuator

Because of the rapid aging of the Japanese population and the acute decrease in young workers in Japan, robots are anticipated for use in performing rehabilitation and daily domestic tasks for nursing and welfare services. Use in environments with humans, safety, and human affinity are particularly important robot hand characteristics. Such robot hands must have flexible movements and be lightweight. Under these circumstances, this study specifically addresses the expansion of a silicone rubber, tendon-driven actuator, which has been developed using a pneumatic balloon. A multifingered robotic hand using the actuator is developed. Moreover, a fuzzy grasping control system is applied to the proposed robotic hand. The robot hand’s development is described incorporating pneumatic balloon actuator with the softness, size, and weight of a human hand. The fuzzy grasping control system is shown to be effective for the proposed robot hand, which can grasp soft objects easily.

Ankle Rehabilitation Device to Prevent Contracture Using a Pneumatic Balloon Actuator

Our proposed rehabilitation device to prevent contracture of the ankle is easy to produce, transport, and install at the time of use in places such as medical institutions. This device is intended for use by hemiplegic people. The ankle is moved when it is worn, preventing ankle contracture. It consists of a new tendon-drive system using a pneumatic balloon actuator, power transfer mechanism, and ankle foot orthosis. This new tendon drive system using a pneumatic balloon was developed as an actuator of this device. The system consists of a tendon and a silicone tube. Both ends of the tube are closed. The tube expands with the supplied air, which distends the silicone tube and thereby pulls the tendon. This simple system is both compact and powerful. Furthermore, its materials and structure make it light. This paper describes characteristics of this tendon drive system using a pneumatic balloon, along with its composition and operation as a rehabilitation device for preventing ankle contracture. Results of operation tests using the device are also presented.