The investigators have developed a novel robot-guided stretching under intelligent control and combine it with active movement training, which helped increase joint ROM, reduce spasticity and joint stiffness, increase muscle force output, and improve locomotion. However, for stroke survivors with sensorimotor impairment, their peripheral muscle may not sufficiently be recruited. Functional electrical stimulation (FES), has been shown its advantage to activate the peripheral muscles for people with neurological conditions. The investigators thus make a hybrid robot-FES rehabilitation system, combining the advantage of robot and FES technologies for stroke motor recovery. The investigators further would like to translate the technologies from lab to home-based training. Thus, the investigators will conduct a randomized, controlled, primarily home-based clinical trial using an ankle robot alone or combined with functional electrical stimulation (FES) to treat sensorimotor and locomotion impairments post-stroke.