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In Japan, approximately 1.1 million people suffer from cerebrovascular diseases such as cerebral stroke, which can further increase due to the aging society. Therefore, rehabilitation for the physical recovery of patients with hemiplegia caused by cerebrovascular disease plays an important role in maintaining and improving their quality of life (QoL). In rehabilitation facilities, crutches and parallel bars are the mainstream, but patients support their body with their arms, causing falls and fatigue, leading to deterioration of motivation in long-term rehabilitation. Although a few hanging-type devices have been developed to cope with such issues, they occupy large space, require time to wear, and have a high introduction cost. In this study, we developed a non-wearing-type pneumatic power assist device for gait rehabilitation to ensure patients can sustain their body weight by pushing up their armpit and quantitatively verified the effectiveness of the device.

In Japan, where aging is faster than ever, the shortage of a young labor force is a serious problem, especially in the nursing field to support care recipients and in the primary industrial field to support heavy labor. Hence, the use of power assist devices that mechanically reduce the burden on the body is drawing increasing attention. This study focuses on the lifting motion, which can be performed by two methods, the squat method and the stoop method; the former involves bending the knee and the latter involves using the waist. The squat method is recommended because the burden on the waist is lower than that in the case of the stoop method. Currently, many types of wearable power assist devices to reduce the burden on the waist have been developed; however, they are based on the stoop method because of their assist mechanism. In this study, we developed a non-wearing type pneumatic power assist device that allows the squat method. After describing the basic concept and assist mechanism, the support effects are confirmed through experiments.

Japan has an aging population, and the number of patients with physical impairment is increasing owing to aging and accidents. A contracture is a state in which joint movements are worsened owing to the hardening and loss of elasticity of the surrounding soft tissue such as muscle and skin, when a patient is immobile or bedridden for long durations. In particular, finger and wrist contractures can cause many inconveniences in daily life. Thus far, some rehabilitation devices have been developed. A power assist glove extends the finger but is difficult for patients to wear. This study focuses on wearability and risk avoidance, and develops a device with two parallel sticks that are driven by pneumatic actuators to simulate the motion of a physical therapist. After verifying the fundamental control performances, the safety function based on the estimated force applied by the patient and the improvement of effectiveness in rehabilitation using a USB camera are discussed.

Industrial robots equipped with various grippers have been introduced in production sites and most of them are electrically driven. Because of the electric actuator’s characteristics, they have no back drivability, making it difficult for them to grasp flexible objects. In this study, therefore, we propose a pneumatically driven robot hand capable of grasping flexible objects by effectively employing the compressibility and back drivability of air.

Japan’s population is aging at a speed unprecedented in the world, and its shortage of caregivers has become a major issue. At the same time, the Internet of Things (IoT) is expected to create unprecedented new value by connecting all people and things, allowing them to share various kinds of knowledge and information. In addition, as artificial intelligence (AI) and big data are undergoing a transformation that is changing the value of human labor, robots incorporating these innovative technologies are expected to solve the problems of the aging society. On the other hand, in the field of nursing care, the relationship between the caregiver and the care-receiver is basically a person-to-person connection. There is a question of how people and technology can coexist and produce new creations in such fields. This special issue on Nursing Robots and Support Systems for Welfare Sites includes one review paper and 23 other interesting papers that cover the following topics: ı Research on independence support and systems to watch over the elderly. ı Research on support systems for diet, recreation, medication, etc. for people with dementia. ı Research on control and sensor systems for vital signs and excretion. ı Research on rehabilitation equipment for the physically handicapped. ı Research on assistive technologies for mobility support. ı Research on upper and lower limb power assistance devices and robots. We thank all authors and reviewers of the papers as well as the Editorial Board of the Journal of Robotics and Mechatronics for their help with this special issue.

It is well known that fluid-powered systems are used practically in almost all industrial fields, including construction, manufacturing, transportation, among others. Nowadays, the rapid growth in the development of the mechanical elements in fluid-powered systems, such as control valves, actuators, and sensors, and the rapid growth in control strategies have given rise to pioneering in some novel application fields in ways that were thought to be impossible a decade ago. High-precision positioning control using the compressible fluid of pneumatic driving systems and multi-legged robots equipped with standalone hydraulic components are simple examples. Moreover, soft robotics based on fluid-powered technologies has attracted attention not only in academia but also in human support fields, which will become more important as Japan’s society ages. This special issue on “Fluid Powered System and its Application” includes one review paper and 22 other interesting papers related to the state of the art in the development of mechanical elements, total drive systems, motion control theory, and concrete applications of fluid-powered systems. We thank all of the authors and reviewers of the papers and hope this special issue helps readers to develop fluid powered systems that will contribute to developments in the academia and industry.

In this study, electromyography is applied to a subject’s forearm to discriminate between intended finger and wrist motions and the resulting signals are used to control a power assist glove. This glove is designed to assist with grasping. The fingers and wrist are moved when the corresponding muscles of the forearm contract simultaneously. Therefore, the intention to move either a finger or a wrist must be discriminated to enable assisting a finger movement by this glove. The introduction of Self-Organizing Maps (SOM) improves the ability to discriminate between these motions. In this study, the effectiveness of a discrimination method using SOM is verified experimentally.

In this study, a fingertip force display device that uses negative pressure is developed. The device can control the resisting force against a finger’s motion by regulating the negative pressure in an air chamber processed in the device. Information about the position of a finger is obtained with a Web camera using AR-Toolkit library, and the resisting force is controlled based on the fingertip position (velocity), which shows the capability of the VR-oriented application and mechanical impedance task. The effectiveness of the proposed system is verified through experiments.

This research focuses on developing a safe, lightweight, power assist device that can be worn by people during lifting or static holding tasks to prevent them from experiencing Low Back Pain (LBP). In consideration of their flexibility, light weight, and large force to weight ratio, two types of pneumatic actuators are employed in assisting low back movement for their safety and comfort. Actuator A is an elongation-type pneumatic rubber artificial muscle that is installed in the outer layer of the garment. Its two ends are fixed on the shoulders and thighs. It can output contractile force, assisting the erector spinae muscles in the same direction. Compared to McKibben-type pneumatic rubber artificial muscle, the elongation type has a larger contraction rate. Actuator B is a layer-type of pneumatic actuator; it is composed of two balloons, and it is installed in the inner layer of the garment. By taking into account the biomechanic structure of the human spine, this device can provide support in two ways. Actuator A acts as an external muscle power generators to reduce the force requirement for the erector spinae muscles. As actuator B acts as a moment arm of the contractile force generated by actuator A, it will increase the effective amount of torque. The device can be worn directly on the body like normal clothing. Because there is no rigid exoskeleton frame structure, it is lightweight and user friendly. The system’s Inertial Measurement Unit (IMU), composed of accelerometer sensors and gyro sensors to measure the human motion signals, can monitor the angles of the human body in real-time mode. By measuring the EMG signal of the human erector spinae muscles, the assistance effectiveness of the proposed device has been proven through experiments.

The purpose of this study is to develop a portable energy-saving type air supply system. A variable volume tank is developed in order to drive a pneumatic actuator with a low discharge pressure in a tank. The developed tank composed of flexible materials can store pneumatic energy by converting it to elastic energy. In this paper, the composition of the system, the structure and characteristic of a variable volume tank and experiment of driving actuator with constant and variable volume tanks are discussed. As a result, the variable volume tank can drive the actuator at a lower supply pressure than with the constant volume tank.

In this study, we focus on a rehabilitation motion of human wrist joint and aim at supporting these rehabilitation training by introducing a mechanical system. A pneumatic parallel manipulator is introduced since it can drive enough D.O.F to correspond to a wrist motion and has inherent compliance characteristics resulted from air compressibility. We propose a new training method for a muscle strengthening training based on ElectroMyoGraphy (EMG), where a payload is set between joint angle and the muscle we want to train directly. In addition, we propose a method to detect muscle fatigue based on a frequency analysis of EMG. The effectiveness of the proposed method is confirmed through some experiments.

The purpose of this study is to develop a pneumatic artificial muscle with a high contractile rate to realize a required performance in a power assist device. The developed muscle is constructed with two nylon bands and an expansion unit. The generated force from the expansion unit is converted to a contraction force by the nylon band. This artificial muscle can be realized the high contractile rate. In this paper, the structure and the characteristics of the developed muscle are described, and then the application of this artificial muscle is discussed.

In this study, a bilateral type pneumatic wearable master-slave device has been developed in order to feed back a force information to the trainer. Developed device is constructed with a master and a slave device using pneumatic rubber muscles. By feeding back the reaction torque to a torque control system of the master device, a master device user can feel the reaction torque from the slave. In this paper, the structure of the developed device, the fundamental characteristics of device are discussed, and then the validity of the developed device is evaluated from the fundamental experiments.

In the future, when the average age of the members of society becomes advanced, an innovative technology to assist the activities of daily living of elderly and disabled people and to assist in the heavy work in nursing will be desired. To develop such a technology, an actuator that is safe and user-friendly is required. It should be small, lightweight, and sufficiently soft. Such an actuator is available in artificial muscle made of pneumatic rubber. We have developed some types of pneumatic rubber artificial muscles and applied them to wearable power assist devices. A wearable power assist device is fitted to the human body to assist the power of muscles that support the activities of daily living, rehabilitation, training, and so on. In this paper, some types of pneumatic rubber artificial muscles developed and manufactured in our laboratory are presented. Furthermore, two kinds of wearable power assist devices driven by the rubber artificial muscles are described. Finally, some evaluations clarify the effectiveness of pneumatic rubber artificial muscle for innovative human assistance technologies.