SoochowExo: a Lightweight Hip Exoskeleton Driven by Series Elastic Actuator with Active-type Continuously Variable Transmission

To overcome the different requirements of torque-velocity characteristics for walking, running, stand-to-sit, sit-to-stand, and climbing stairs, we propose a novel concept for actuator design, namely, a series elastic actuator with actively variable reduction ratio transmission. The reduction ratio can be adjusted in real-time to realize variable torque-velocity characteristics. A novel lightweight wearable hip exoskeleton driven by a series elastic actuator with actively variable reduction ratio transmission, named SoochowExo, has been developed in this paper for use in the elderly population. The weight of the whole hip exoskeleton is 1.8 kg (excluding batteries), including three actuators and the frame. The benchtop tests and the preliminary human subject tests further confirm the design and controller.