WASHINGTON, D.C., Oct. 25, 2016 — Stroke and spinal cord injury patients often require gait rehabilitation to regain the ability to walk or to help strengthen their muscles. Wearable “robot-assisted training” is quickly emerging as a method that helps improve this rehab process.
In a major advance, researchers from Beihang University in China and Aalborg University in Denmark have designed a lower-limb robot exoskeleton — a wearable robot — that features natural knee movement to greatly improve patients’ comfort and willingness to wear it for gait rehab.
As the team reports this week in Review of Scientific Instruments, from AIP Publishing, their robotic exoskeleton is intended to help stroke patients strengthen their physical fitness, aid the rehabilitation training of paralyzed patients, or to assist those who need help performing daily activities.
Exoskeleton robots aren’t new — they’ve been studied extensively and many designs have focused on lower limbs. This team’s approach focused instead on the knee joint, one of the most complex mechanical systems within the human body and a critical player during gait.
The knee joint’s motion is actuated by several skeletal muscles along its articular surfaces, and its center of rotation moves. The researchers wondered if a parallel mechanism similar to skeletal muscles would be useful for designing a bionic knee joint.
“Our new design features a parallel knee joint to improve the bio-imitability and adaptability of the exoskeleton,” explained Weihai Chen, a professor at Beihang University’s School of Automation Science and Electrical Engineering, in Beijing, China.
Specifically, the team’s exoskeleton taps a hybrid serial-parallel kinematic structure consisting of a 1-degree of freedom (DOF) hip joint module and a 2-DOF knee joint module in the sagittal plane. And a planar 2-DOF parallel mechanism helps to fully accommodate the motion of the human knee — enabling rotation and relative sliding.