Isao Kikutani

Development of an endskeleton type power assist suit using pneumatic artificial muscles with amplification mechanism

Lifting heavy objects increases the risk of low back pain. In this study, we calculate the load exerted on the human body during an actual lifting operation. To assist lifting, we propose an endoskeleton-like suit that exerts an assistive force. A prototype of the assist suit is developed in this study. The force is exerted by a straight-fiber-type artificial muscle combined with an amplification mechanism. The notion of assistive force was subjectively evaluated by wearers, and confirmed in on a visual analogue scale. The electromyography signals of wearers were decreased, confirming the subjective assist effect.

Semi-endoskeleton-type waist assist AB-wear suit equipped with compressive force reduction mechanism

In recent years in Japan, over half of all workers suffered from lower back pain. This has become a social problem that needs to be addressed. To reduce its occurrence, we developed a flexible, high-output waist assist suit called “AB-Wear” in a previous study. The AB-Wear suit can assist human motion and reduce muscular fatigue of the waist. However, the assistive forces of the device generate compressive forces on the backbone, which have adverse effects on the body. Hence, in this study, we propose an exoskeleton-type AB-Wear equipped with a compressive force reduction mechanism, called “semi-endoskeleton-type AB-Wear”. This device has a reduction mechanism similar to a flexible flat spring behind the upper body. Because of this structure, this device can generate an effective assistive force. First, we explain the difference between the semi-endoskeleton-type AB-Wear and the previous device. Then, we model the semi-endoskeleton-type AB-Wear because the model is used for its operation. Moreover, its effectiveness is confirmed using musculoskeletal simulation. Finally it is evaluated by measuring surface electromyography (EMG) on a subjects body to confirm its effectiveness with a real body. The EMGs of the wearer with and without the suit are compared. The usefulness of the AB-Wear is confirmed by simulation and experiment.

Development of endoskeleton type knee auxiliary power assist suit using pneumatic artificial muscles

Lower back pain continues to be an issue worldwide. One cause of lower back pain is the burden on the lumbar region caused by the handling of heavy objects. To reduce this burden on the lumbar region in the lifting, the Ministry of Health, Labour and Welfare in Japan has recommended a lifting technique called “squat lifting.” However this technique, which supports a large force on the knee, is not very popular. Therefore, to spread the use of squat lifting, we aimed to develop a power assist suit for knee auxiliary. In this study, firstly, the validity of the squat lifting in lower back pain was measured. Next, to construct a prototype based on the target value, the knee joint moments from motion analysis of squat lifting was estimated. Finally, the prototype was mounted on a human body to evaluate its performance. And we confirmed the effectiveness of the prototype.

Development of non-rotating joint drive type gastrocnemius-reinforcing power assist suit for squat lifting

Lower back pain is a major health concern worldwide. One cause of lower back pain is the burden on the lumbar region caused by the handling of heavy objects. To reduce this burden, the Ministry of Health, Labour and Welfare in Japan has recommended “squat lifting.” However, this technique, which supports a large force on lower limbs, is not very popular. Therefore, we aimed to develop a power assist suit for squat lifting. In this paper, we propose a gastrocnemius-reinforcing mechanism. Next, we discuss estimation of joint torque from motion analysis of squat lifting in order to construct a prototype. Finally, we describe the performance of the prototype mounted on a human body. The %MVC of the gastrocnemius while performing squat lifting was reduced by 34% using the prototype assist suit compared with the value without using the suit.

Development of a lightweight power-assist suit using pneumatic artificial muscles and balloon-amplification mechanism

Low back pain of workers is increased in workplaces that involve hard work. It is caused by excessive loading of the waist joint and muscle fatigue. Therefore, power-assist suits have been developed to decrease the load on the waist joint. However, previous power-assist suits have had problems such as low output or heaviness. Thus, we have developed an assist suit that is lightweight and exerts a large force. A balloon actuator and pneumatic artificial muscles are attached to assist suit as the actuators. The assist suit has various desirable features: lightweight, flexibility, and high output. First, human motion is analyzed for the development of the assist suit. The assist suit is developed to assist the waist joint torque. The assist suit is modeled, and the theoretical values of its generation force are estimated using an assist-suit model. Finally, the assist suit is evaluated by measuring the surface electromyography (EMG). The EMG of the wearer is compared with that without the suit. The effectiveness of the assist suit is confirmed by a decrease in EMG.

Effective motion assistance using a passive force endoskeleton power assist suit

Lower back pain accounts for more than half of all reported on-the-job ailments, escalating from a personal challenge to a broader societal challenge. Researchers have developed a power assist suit intended prototype to reduce the incidence of lower back pain in the workplace when process automation is not possible. Equipped with two pneumatic actuators, the prototype suit is lightweight, flexible, and efficient. The prototype suit can assist human motion using passive and active forces. In this study, researchers confirmed the effectiveness of passive assistive force. Two types of motion were considered: lifting and unloading in a crouching position and carrying. Researchers first analyzed the subject motions using video analysis software. Waist joint loads were estimated using motion analysis results and a human link model. Second, researchers determined the power assist suits operational parameters and developed a power assist suit model. Lastly, researchers confirmed the passive force prototype suits effectiveness based on measured changes in generated force and electromyography.