Upper-limb assistive device for the elderly at home

We present an upper-limb assistive device for the elderly at home. In previous researches, the passive systems were manually adjusted to support arm movement with holding different weights of objects, and the active systems equipped with multiple actuators and sensors were too complex and expensive to use in hospitals and rehabilitation clinics as well as homes. If the assist for the activities of daily livings (ADLs) is to be delivered not just in the clinic, but also in the home, the system can facilitate the independence of the elderly in ADL. The presented assistive device consists of one active joint for the vertical motion and three passive joints for the horizontal motions. In order to reduce the required motor torque induced from the weights of the user arm and links of the device, a gravity compensation mechanism using parallel links with two springs was implemented. The vertical assistive force is provided according to the user´s intention that is extracted from the surface electromyography (sEMG) and interaction force. The effectiveness of the assistive force was validated by comparing the sEMG signals for the movements with and without the assistance.