OLLE

Orthotic Lower-Body Locomotion Exoskeleton (OLLE): A Compliant Lower-Body Exoskeleton to Enable Balanced Walking for Patients with Spinal Cord Injuries

overview

Spinal cord injuries can lead to complete leg paralysis, drastically limiting mobility and reducing quality of life. Significant progress has been made towards wearable exoskeletons that provide some ability to walk, but these require the use of crutches, which create unnatural loads on the wearer, as well as restricting use of the hands and arms. The objective of this research is to develop a lower body exoskeleton able to balance and walk without the use of crutches, thus allowing the wearers to interact with their environment and maintain proper posture. The resulting platform improves the overall quality of life for those with spinal cord injury by granting them a level of mobility that is currently unachievable.
This work applies methods for the advancement in the field of humanoid robots to the design of exoskeletons for functionally impaired persons. Specifically, the project applies a method called whole-body control, which finds motions that resolve multiple motion objectives at once, to a lower body exoskeleton with 12 degrees of freedom, providing a range of movement similar to natural human locomotion, with the exception of ankle yaw. High fidelity torque control is achieved using series elastic actuators to enable compliant locomotion of the wearer.
Repurposing of OLLE: The robot is being repurposed for VR force feedback applications and shares the same goals as those of the Forcebot project. The key difference between Forcebot and OLLE is that Forcebot is a gantry with 2 degrees of freedom, while OLLE has a greater number of actuators that are arranged in a manner more aligned with the structure of the human body. Therefore, OLLE will be able to offer greater degrees of freedom in movement and more complex force feedback to the user’s lower body. The robot has been in the process of being mechanically restored. To meet the power requirements of the robot’s new application, water cooling has been implemented to increase the power capabilities of the actuators. Future work includes implementing controls to be able to move the robot to meet target trajectories and apply force feedback to the user’s lower body. The robot has been in the process of being mechanically restored. To meet the power requirements of the robot’s new application, water cooling has been implemented to increase the power capabilities of the actuators. Future work includes implementing controls to be able to move the robot to meet target trajectories and apply force feedback to the user’s lower body.

TEam

Alexander Leonessa

Professor, Mechanical Engineering Department

Virginia Tech, Blacksburg, VA 24060

Alan Asbeck

Assistant Professor, Mechanical Engineering Department

Virginia Tech, Blacksburg,VA 24060