Motion Control of Robots Based on Sensings of Human Forces and Movements

1.1 Requirement for arm therapy and clinical background The percentage of aged persons is continuously increasing in many countries, which is becoming a social problem demanding concern from different fields including social science, medical science and engineering. This trend is particularly rigorous in Japan where the aged (over 65 years old) accounted for 20.8% of the total population up to 2006 (Statistics Bureau, 2007). In the elderly, the prevalence of physical deterioration is sharply high, and their physical deterioration generally leads to degeneration of some motor functions. Besides, Hemiplegic limb impairment after a stroke which is a common disease among the aged, is becoming a global issue. Both motor function deterioration and disability have an indirect influence on brain degeneration. Thereby, strength enhancement and function recovery are necessary in the aging society. Moreover, physical therapy resources are quite limited, and the rehabilitation therapy places a large economic burden on patients. Under these conditions, considerable interest has been stimulated in the development of upper limb rehabilitation robots which can act as a therapeutic aid for therapists in rehabilitation training.