Current wearable rehabilitation and assistive devices are either 1: powerful and active but bulky and made of rigid elements such as exoskeletons and prosthesis, or 2: flexible and passive but have limited functionalities, such as joint braces. Realizing a wearable rehabilitation technology that is light and soft yet active and powerful has been a grand challenge for researchers due to a persisting gap in current actuation technology: there is still no soft actuator that is portable, i.e. can be operated by on-board power sources, scalable to be adopted to different joint sizes and still can have short response time and high output force-to-size ratio in order to be able to assist joint's motions. It is believed that the emerging field of soft robotic will be the foundation of future assistive technology, if the above-mentioned gap in regards to the actuator part can be filled. Without meeting this need, rehabilitation and assistive technologies will be limited to current passive braces or bulky exoskeletons and prosthetic devices that are proven to not be very efficient and functional for many applications and are sometimes even dangerous for patients.

Motivated by the aforesaid challenges, a novel Electromagnetic Soft Actuator (ESA) is presented which is highly scalable and can be easily actuated by on-board batteries. ESAs are capable of mimicking behavior of Actin and Myosin filaments by producing linear force and contraction. The ESA is highly scalable which allows us to miniaturize it and create artificial sarcomere by assembling them in parallel and series fashion.