In this research we introduce a wearable sensory system for motion intention estimation and control of exoskeleton robot. The system comprises wearable inertial motion sensors and shoe-embedded force sensors. The system utilizes an instrumented cane as a part of the interface between the user and the robot. The cane reflects the motion of upper limbs, and is used in terms of human inter-limb synergies. The developed control system provides assisted motion in coherence with the motion of other unassisted limbs. The system utilizes the instrumented cane together with body worn sensors, and provides assistance for start, stop and continuous walking. We verified the function of the proposed method and the developed wearable system through gait trials on treadmill and on ground. The achievement contributes to finding an intuitive and feasible interface between human and robot through wearable gait sensors for practical use of assistive technology. It also contributes to the technology for cognitively assisted locomotion, which helps the locomotion of physically challenged people.

This paper proposes a novel semiactive ankle-foot orthosis (AFO) called SmartAFO equipped with an elastic link mechanism. The design of the device is based on the understanding of gait biomechanics for gait assistance against paralysis and other gait abnormalities affecting the ankle joint function. The elastic link at the core of the developed AFO is a 1-degree-of-freedom linear-motion system, capable of regulating its viscosity via a magnetorheological fluid and an electromagnetic coil. The link is also integrated with a compression spring that allows it to store and release energy based on its coil current. This design enabled a semiactive AFO that can mitigate foot slap and toe drag without adversely affecting push-off or other gait phases. We present the development of SmartAFO and the results of experiments conducted on healthy people to verify its support functions compared to a commercial AFO. The results showed that SmartAFO can provide controllable braking torque at the heel contact, avoid ankle motion obstruction during the push-off phase, and support toe lift during the swing phase.

This study proposes a novel standing mobility device aimed at supporting and assisting people with disabled lower limbs. The developed mobility device is capable of assisting voluntary postural transition between standing and sitting by a passive exoskeleton equipped with gas springs, in addition to providing wheeled locomotion in a standing posture using two in-wheel motors. The device allows voluntary natural assisted sit-to-stand motions. Furthermore, it can be operated in the standing posture without using hands. This paper describes the development and assessment of the standing mobility device as well as a pilot study conducted with a person with spinal cord injury. Then, investigation of the mechanical characteristics of the device is presented for further analysis of sit-to-stand and stand-to-sit transfer assistance.

Lower leg muscle activity contributes to body control; thus, monitoring lower leg muscle activity is beneficial to understand the body condition and prevent accidents such as falls. Amplitude features such as the mean absolute values of electromyography (EMG) are used widely for monitoring muscle activity. Garment-type EMG measurement systems use electrodes and they enable us to monitor muscle activity in daily life without any specific knowledge and the installation for electrode placement. However, garment-type measurement systems require a high compression area around the electrodes to prevent electrode displacement. This makes it difficult for users to wear such measurement systems. A less restraining wearable system, wherein the electrodes are placed around the ankle, is realized for target muscles widely distributed around the shank. The signals obtained from around the ankle are propagated biosignals from several muscles, and are referred to as distal EMG signals. Our objective is to develop a sock-type wearable sensor for estimating lower leg muscle activity using distal EMG signals. We propose a signal processing method based on multiple bandpass filters from the perspectives of noise separation and feature augmentation. We conducted an experiment for designing the hardware configuration, and three other experiments for evaluating the estimation accuracy and dependability of muscle activity analysis. Compared to the baseline based on a 20-500 Hz bandpass filter, the results indicated that the proposed system estimates muscle activity with higher accuracy. Experimental results suggest that lower leg muscle activity can be estimated using distal EMG signals.

Study Design: Prospective experimental study in humans.Purpose: To determine whether the hybrid assistive limb (HAL) for Care Support can reduce lumbar load during a patient transfer.Overview of Literature: The prevalence of work-related low back pain (LBP) among nurses is high. In particular, transferring patients poses a high risk for LBP due to the large lumbar load. Attempts to reduce the lumbar load are crucial to avoid the risk of LBP. Therefore, we investigated the effects of the HAL for Care Support.Methods: Nineteen volunteers (16 men, three women) lifted a 60-kg doll from a seated position to a standing position. The first transfer was performed without the HAL for Care Support, and the second was performed with the HAL for Care Support assistive robot. We evaluated transfer performance, the visual analog scale (VAS) score for lumbar fatigue, and electromyogram analyses of the trunk and hip.Results: Four participants (two men, two women) succeeded with the HAL for Care Support even though they were unable to perform the task without it. The mean lumbar fatigue VAS score for all participants without the HAL for Care Support was 62 mm, while that with it was 43 mm. With lumbar assistance from the HAL for Care Support, subjective lumbar fatigue during the transfer decreased significantly. A power analysis indicated adequate statistical power to detect a difference in the VAS score for lumbar fatigue (0.99). The activity of the left gluteus maximus alone increased significantly during transfers with the HAL for Care Support. No adverse events occurred during use of the HAL for Care Support for transfers.Conclusions: The HAL for Care Support was able to reduce lumbar load in a simulated patient transfer.