As one of the leading causes of severe long-term disability [1], stroke (ischemic and hemorrhagic) results in 795 K new patients every year (16.9 M worldwide) in addition to the existing 6.6 M stroke patients (33 M worldwide). Hemiparesis (one-sided weakness) or hemiplegia (one-sided paralysis) frequently occurs with spasticity (stiff or tight muscles) and joint/muscle coupling affects 80% of stroke victims. The specific functionality and severity depend on the brain trauma position and size. The patients’ participation in activities of daily living (ADLs) is affected, creating a burden on themselves, their families, and society [2]. Of particular interest is that movement capabilities of stroke patients are normally more severely affected on one side, depending on which brain hemisphere has trauma. The bilateral training mode discussed later is based on this observation.

Many poststroke patients are able to regain some capabilities after rehabilitation training. However, due to the limitation of time/skills of human physical therapists, stroke survivors often do not receive sufficient training and do not recover the capabilities they should. Rehabilitation robots, which always have contact with the human’s body and are thus “wearable,” have the potential to automate the training process and increase the exercise dose while reducing the service cost. As average life expectancy is lengthened by improved medical treatment, the absolute amount of stroke survivors is increasing and rehabilitation wearables are expected to have a promising market.