[Paper Review] Design and Approach of Team IHMC in the 2016 Cybathlon.

Robert J. Griffin, Tyson C. Cobb+9 more|arXiv (Cornell University)|Feb 28, 2017

Prosthetics and Rehabilitation Robotics12 references3 citations

TL;DR

This paper presents Mina v2, a novel powered exoskeleton with active dorsiflexion/plantar flexion at the ankle, designed to enhance mobility for paraplegic pilots. By integrating powered ankle actuation into gait strategies, the team achieved a consistent walking speed of 0.29 m/s, enabling them to secure 2nd place overall in the 2016 Cybathlon Powered Exoskeleton Competition.

ABSTRACT

Exoskeletons are a promising technology for enabling individuals with mobility limitations to walk again. As the 2016 Cybathlon illustrated, however, we have a considerable way to go before exoskeletons have the necessary capabilities to be incorporated into daily life. Most exoskeletons, power only the hip and knee flexion, whereas we present a new exoskeleton, Mina v2, that includes a powered dorsi/plantar flexion. As our entry to the 2016 Cybathlon Powered Exoskeleton Competition, Mina v2's powered ankle allowed us to explore its effectiveness on powered exoskeletons for pilots with paraplegia. We designed our gaits around the incorporation of powered ankle plantar flexion to help improve mobility. Using this approach, our pilot was able to navigate the tasks quickly, especially those that required ascending, and reliably achieve average, conservative walking speeds of 0.29 m/s. This enabled our team to place 2nd overall in the Powered Exoskeleton Competition in the 2016 Cybathlon.

Motivation & Objective

• To address the limited functionality of existing exoskeletons, which typically only power hip and knee flexion.
• To investigate the impact of adding powered dorsiflexion/plantar flexion at the ankle joint on exoskeleton performance.
• To develop gait strategies that effectively utilize powered ankle actuation to enhance mobility for paraplegic users.
• To improve walking speed and reliability during complex mobility tasks in a competitive setting like the Cybathlon.

Proposed method

• Design and implementation of Mina v2, a lower-limb exoskeleton with active actuation at the ankle joint for both dorsiflexion and plantar flexion.
• Development of gait patterns specifically tailored to leverage powered ankle movement to improve propulsion and stability.
• Integration of the exoskeleton with a paraplegic pilot to test performance in real-world task scenarios.
• Execution of the exoskeleton in the 2016 Cybathlon Powered Exoskeleton Competition to evaluate real-time performance.

Experimental results

Research questions

• RQ1 How does the inclusion of powered ankle plantar flexion affect exoskeleton performance in mobility tasks?
• RQ2 Can gait strategies incorporating powered ankle actuation improve walking speed and stability for paraplegic users?
• RQ3 To what extent does powered ankle assistance enhance performance in ascending and navigating complex terrain?
• RQ4 Can a powered exoskeleton with ankle actuation achieve competitive performance in a real-world competition like the Cybathlon?

Key findings

• The addition of powered dorsiflexion/plantar flexion in Mina v2 significantly enhanced mobility performance compared to exoskeletons with only hip and knee actuation.
• The team achieved an average walking speed of 0.29 m/s, which was described as conservative and reliable across tasks.
• The powered ankle joint provided measurable benefits during ascending tasks, contributing to faster navigation times.
• The exoskeleton enabled the pilot to complete all competition tasks successfully, resulting in a 2nd place finish in the 2016 Cybathlon Powered Exoskeleton Competition.