Design and Control of a Novel Underactuated Soft Exosuit.

Soft exosuit is widely researched to assist walking. Lacking of physical compliance in hip exosuits restricts wearing comfort of the system. This paper presents design and control of an underactuated hip exosuit with soft series elastic actuator (SSEA) that exhibits customized physical compliance. The actuation module is mounted on the backpack, and each motor is responsible for hip flexion and extension of one side. In high level control, a phase oscillator model was used for assistive force generation. In low level control, PID controllers were applied for flexion and extension forces tracking, respectively. Experimental results indicate the proposed hip exosuit can assist walking with physical compaliance and provide suitable force at the accurate timing. This work enables studies of exosuits with underactuated mechanism and actuator with physical compliance to pave the way for application of wearable robots in real-world.