Rubber Actuator Research Articles

パワーアシスト装具を用いたピンポイント筋力制御

The demand for rehabilitation robots is increasing for the upcoming aging society. Power-assisting devices are considered promising for enhancing the mobility of elderly and disabled people. Other potential applications are for muscle rehabilitation and sports training. The main focus of this research is to control the load of selected muscles by using a power-assisting device, thus enabling “pinpointed” motion support, rehabilitation, and training by explicitly specifying the target muscles. By taking into account the physical interaction between human muscle forces and actuator driving forces during power-assisting, the feasibility of this pinpointed muscle force control is analyzed as a constrained optimization problem. Using our developed power-assisting device driven by pneumatic rubber actuators, the validity of the method is confirmed by measuring surface electromyographic (EMG) signals for target muscles.

Analysis of actuating mechanics characteristics for a flexible miniature robot system

Based on the inchworm movement, a miniature endoscope inspection robot system with a flexible structure is designed. The system is actuated by a pneumatic rubber actuator with three degrees of freedom, and it holds its position by air chambers. The actuating mechanics characteristics of the robot are analyzed. An electro-pneumatic pressure system is designed to control the motion of the robot. Results of the calculation and experiments are consistent, and the robot system can move smoothly in a soft tube.

STUDY ON A HIGH PERFORMANCE INSOLE WITH HUMAN COMPATIBILITY

In recent years, accidents of bone fracture with elderly people increase because of tendency to fall by a little step in a house. As one of this cause, it is considered that a center of gravity position with foot parts of elderly people is changed. Therefore, in order to solve this problem, we propose a new type of insole with high performance by making use of sponge-core-soft rubber actuator (SCSRA). In this study, we apply the actuator to an insole in order to support walking motion. That is to say, a new type of insole to distinguish the foot motion (Pitch or Roll motion) is proposed. To clear the performance of the insole, we develop a test device that is constructed with rotary actuators and a cylinder. In this paper, the mechanism of the proposed insole is explained and basic performances of the proposed mechanism are clarified through some experimental results.

NEW PNEUMATIC ACTUATORS PRODUCING BREAKTHROUGH IN MECHATRONICS

New pneumatic actuators developed in the author's laboratory will be presented with their applications to new mechatronics. Examples of them are a pneumatic rubber actuator for compliant robots, a micro pneumatic tube actuator assisting the colonscope insertion, a pneumatic stepping motor with high torque and resolution, a pneumatic drive bicycle, an intelligent pneumatic cylinder which has encoder and micro CPU realizing local control and communication functions, and a new control method utilizing multiplex pneumatic transmission for pneumatic systems with multi-degrees of freedom.

脳卒中片麻痺患者に健側の動作方向を教示する上肢訓練支援ロボット(NEDOシンポジウム「生活支援ロボットの最前線」(日本生活支援工学会企画),特別企画)

This paper describes a development of support robot for training of a Hemiplegia patient. This robot is based on technologies of power assisting suit. Our power assisting suit is constructed on the idea of "Soft-Mechtronics" that is safety and relief for human by flexible structres, pliable controls and soft actuators. We constructed this power assisting suit by plastic exoskeleton cloth and pneumatic rubber actuators. So the patient does not feel fear to this robot. Rehabilitation needs motivation of the patient. This robot moves paralysis side arm of patient based on signals from moving of health side arm.

Intelligent phase plane switching control of a pneumatic muscle robot arm with Magneto-Rheological Brake

Pneumatic cylinders are one kind of low cost actuation sources which have been applied in industrial and robotics field, since they have a high power/weight ratio, a high-tension force and a long durability. To overcome the shortcomings of conventional pneumatic cylinders, a number of newer pneumatic actuators have been developed such as McKibben Muscle, Rubber Actuator and Pneumatic Artificial Muscle (PAM) Manipulators. However, some limitations still exist, such as the air compressibility and the lack of damping ability of the actuator bring the dynamic delay of the pressure response and cause the oscillatory motion. In addition, the nonlinearities in the PAM manipulator still limit the controllability. Therefore, it is not easy to realize motion with high accuracy and high speed and with respect to various external inertia loads.

Intelligent switching control of a pneumatic muscle robot arm using learning vector quantization neural network

Pneumatic cylinders are one of the low-cost actuation sources used in industrial and prosthetic application, since they have a high power/weight ratio, high-tension force and long durability. However, problems with the control, oscillatory motion and compliance of pneumatic systems have prevented their widespread use in advanced robotics. To overcome these shortcomings, a number of newer pneumatic actuators have been developed, such as the McKibben Muscle, Rubber Actuator and Pneumatic Artificial Muscle (PAM) Manipulators. In this paper, the solution for position control of a robot arm with slow motion driven by two pneumatic artificial muscles is presented. However, some limitations still exist, such as a deterioration of the performance of transient response due to the changes in the external load. To overcome this problem, a switching algorithm of the control parameter using a learning vector quantization neural network (LVQNN) is proposed in this paper. The LVQNN estimates the external load of the pneumatic artificial muscle manipulator. The effectiveness of the proposed control algorithm is demonstrated through experiments with different external working loads.

MF215 空気圧ゴム人工筋の張力測定によるパワーアシスト装具の姿勢推定(MF21 パワーアシスト,あたり前のことを知る)

MF215 空気圧ゴム人工筋の張力測定によるパワーアシスト装具の姿勢推定(MF21 パワーアシスト,あたり前のことを知る)

Intelligent phase plane switching control of pneumatic artificial muscle manipulators with magneto-rheological brake

The pneumatic artificial muscle (PAM) is undoubtedly the most promising artificial muscle for the actuation of new types of industrial robots such as rubber actuator and PAM manipulators because it provides these advantages such as high strength and high power/weight ratio, low cost, compactness, ease of maintenance, cleanliness, readily available and cheap power source, inherent safety and mobility assistance to humans performing tasks. However, some limitations still exist, such as the air compressibility and the lack of damping ability of the actuator bring the dynamic delay of the pressure response and cause the oscillatory motion. In addition, the nonlinearities in the PAM manipulator still limit the controllability. Therefore, it is not easy to realize motion with high accuracy and high speed and with respect to various external inertia loads in order to realize a human-friendly therapy robot. To overcome these problems a novel controller which harmonizes a phase plane switching control method (PPSC) with conventional PID controller and the adaptabilities of neural network, is newly proposed. In order to realize satisfactory control performance a variable damper, magneto-rheological brake (MRB), is equipped to the joint of the manipulator. Superb mixture of conventional PID controller and an intelligent phase plane switching control using neural network (IPPSC) brings us a novel controller. The experiments were carried out in practical PAM manipulator and the effectiveness of the proposed control algorithm was demonstrated through experiments, which had proved that the stability of the manipulator can be improved greatly in a high gain control by using MRB with IPPSC and without regard for the changes of external inertia loads.

1A1-C09 インテリジェントラバチュエータの開発 : 第4報:柔軟圧力センサの開発と圧力制御

This study aims at development of a soft intelligent rubber actuator of McKibben style. McKibben rubber actuator is an artificial muscle, which is pneumatically driven. At present, almost servo systems with this rubber actuator are driven with external sensors, which cause lowering the compliance and growing the size. In this report, we developed the soft pressure sensor using rubber and conductive film and embed the sensor in the actuator. The characteristics of the sensor had creep behavior, therefore we proposed the new idea of applying the mechanical model to the sensor model. Using the model, we realized servo pressure control successfully.

1P1-A10 人間親和性を有する高機能靴開発のための基礎研究

In recent years, accidents of bone fracture with elderly people increase because of tendency to fall by a little step in a house. As one of this cause, it is considered that the center of gravity position with foot parts is changed. Therefore, in order to solve this problem, we propose a new type of shoes with high performances by making use of sponge-core-soft rubber actuator. The actuator can estimate an external force by measurement of pressure in the actuator. Thus, when some actuators are used in the bottom of the shoes, it is possible to estimate distribution of the external forces with foot parts. Further, the actuator can control the stiffness by pressure in the actuator. Therefore, the actuators can adjust the center of gravity position of the foot parts. In this paper, the mechanism of the proposed shoes is explained and basic performances of the proposed mechanism are clarified through some experimental results.

3116 空気圧システムを用いた高機能靴に関する基礎研究(S45-3 フルードパワー機器 III,S45 フルードパワー機器)

In recent years, a walking sport attracts attention for healthy maintenance. This is because that the sport is very easy to execute. However, with respect to elderly people, the accidents of bone fracture increase because of tendency to fall by a little step in a house. As one of this cause, it is considered that the center of gravity position with foot parts is changed. Therefore, in order to solve this problem, we propose a new type of shoes with high performances by making use of soft rubber actuator. In this paper, the mechanism of the proposed shoes is explained and basic performances of the proposed mechanism are clarified through some experimental results.

Soft Mechanism by using a Sponge-Core-Soft-Rubber Actuator for Welfare Machines

In care activity or rescue activity, hands that can grasp creatures are sometimes needed. Therefore, it is considered that the soft mechanism that uses pneumatic elements is useful to realize such hands. In this paper, we propose a new type of soft actuator (Sponge-Core-Soft Rubber Actuator) in which a sponge rubber is covered with silicon rubber. The structure of the sponge rubber is divided into two types. One is single-layer type and the other is two-layer type (a flat type and a clipping type). In order to clarify the differences in characteristics of each actuator, we examine the basic characteristics of the actuators. Further, the control performances of both position and force are studied to realize a hybrid element. From some experimental results, the control performance of the two layers type actuator is illustrated.

Intelligent Switching Control of Pneumatic Artificial Muscle Manipulator

Problems with the control, oscillatory motion and compliance of pneumatic systems have prevented their widespread use in advanced robotics. However, their compactness, power/weight ratio, ease of maintenance and inherent safety are the factors that could potentially be exploited in sophisticated dexterous manipulator designs. These advantages have led to the development of novel actuators such as the McKibben Muscle, Rubber Actuator and Pneumatic Artificial Muscle Manipulators. However, some limitations still exist, such as deterioration of the performance of transient response due to the change of the external inertia load in the pneumatic artificial muscle manipulator. To overcome this problem, switching algorithm of control parameter using learning vector quantization neural network (LVQNN) is newly proposed, which estimates the external inertia load of the pneumatic artificial muscle manipulator. The effectiveness of the proposed control algorithm is demonstrated through experiments with different external inertia loads.

2A2-45 人間親和性を有するハイブリッドプレートに関する基礎研究(講演,生体計測IV)

In order to develop human friendly elements, we developed a sponge core soft rubber actuator which is constructed with a silicone and a sponge rubber. With respect to the structure of the actuator, a sponge rubber is covered with a silicon rubber. Therefore, air can be changed into the sponge chamber. Further since the actuator has no sliding parts, there is no influence of friction force. Therefore, the actuator can estimate external force by making use of the inner pressure. In this study, we investigate force control performance of the actuator. Furthermore the force sensing ability of the actuator is clarified through some experimental results.

Improvement of the control performance of pneumatic artificial muscle manipulators using an intelligent switching control method

Problems with the control, oscillatory motion and compliance of pneumatic systems have prevented their widespread use in advanced robotics. However, their compactness, power/weight ratio, ease of maintenance and inherent safety are factors that could be potentially exploited in sophisticated dexterous manipulator designs. These advantages have led to the development of novel actuators such as the McKibben Muscle, Rubber Actuator and Pneumatic Artificial Muscle Manipulators. However, some limitations still exist, such as a deterioration of the performance of transient response due to the changes in the external inertia load in the pneumatic artificial muscle manipulator. To overcome this problem, a switching algorithm of the control parameter using a learning vector quantization neural network (LVQNN) is newly proposed. This estimates the external inertia load of the pneumatic artificial muscle manipulator. The effectiveness of the proposed control algorithm is demonstrated through experiments with different external inertia loads.

Vibration control of a flexible structure using a hybrid mount

This paper presents vibration control of a flexible beam structure using a hybrid mount which consists of elastic rubber and piezoelectric stack actuator. After identifying stiffness and damping properties of the rubber and piezoelectric elements, a mechanical model of the hybrid mount is established. The mount model is then incorporated with the beam structure, and the governing equation of motion is obtained in a state space. A sliding mode controller is designed in order to actively attenuate the vibration of the beam structure subjected to high-frequency and small magnitude excitations. The controller is experimentally realized and measured control responses such as acceleration of the beam structure and force transmission through the hybrid mount are evaluated and presented in both frequency and time domains.

Soft Planar Actuator using Pneumatic-Rubber Balls

The manipulation of fragile and shapeless objects requires an actuator with enough flexibility and safety not to injure manipulated objects. To cope with such requirements, soft actuators have been developed, most of which utilize elastic deformation of a rubber tube or balloon caused by compressed air pressure. Such a pneumatic rubber actuator is expected to be effectively used as a flexible and friendly soft actuator in various fields. In this study, to realize a flexible pneumatic carrier system, a soft planar actuator using rubber balls has been developed assuming that the actuator directly contacts carried objects. This paper describes a fundamental principle of operation, a control method and experimental results. Additionally, a small sized soft planar actuator made of silicone rubber is described. The results show the effectiveness of the proposed actuator mechanism.

Development of In-Pipe Mobile Robot Using Pneumatic Soft-Actuator

In this paper, soft-actuators are developed, which are made of a silicon rubber and are driven with a pneumatic power. The silicon rubber has a flexibility, and the pneumatic power has a compressibility. Using these characteristics, soft-actuators can be realized. A rubber can be molded in some shapes and designs, and rubber actuators can move in extending and bending.An in-pipe mobil, robot is composed of two holding actuators and a traveling actuator. The robot is fixed by holding actuators on both sides, a traveling actuator is equipped between holding actuators. The influence of the tube length (from servo valve to robot) is compensated by an improved control system. The compensator comprises of expresses the transfer function which is identified characteristics of the robot. Owing to the softness of the actuator and the pneumatic compliance, the robot can travel in an arbitrary shape pipe, such as a circle or a non-circle. The validity of this robot is confirmed through some experiments.

Pneumatic Rubber Actuator Driven by Elastic Traveling Waves.

"Bubbler, "a new type of pneumatic rubber actuator realizing linear motion, has been designed and developed.Bubbler consists of a silicone rubber slab, and its interior is divided into many chambers.When pressure is applied to successive chambers sequentially, the surface of the rubber slab produces linear traveling waves which drive objects placed on the actuator.This actuator can be applied as a mobile robot base or a conveyor.The mechanism and characteristics of this actuator are discussed in this report.The characteristics of the actuator can be estimated by applying a simple linear analysis mehtod for various driving conditions:frequency, length, and duty ratio of the generated waves, vertical loads, and horizontal loads.Slip ratio or the error between the theoretical and experimental velocity of the actuator is within 20%.Experimental results are very promising.The walking speed of the prototype, 63mm×60mm×9mm in size, was found to be 4.7mm / s and the load-to-weight ratio in the order of 40:1.