Design, implementation and validation of an exoskeletal robot for locomotion studies in rodents

Abstract

Growing interest in robotic treatment of patients with neurological injury motivates the development of therapeutic robots for basic research into recovery. Though humans are the ultimate beneficiaries, basic research frequently involves rodent models of neurological injury, which motivates robotic devices that can interact with rats or mice. Currently, available apparatus for locomotion studies of rodents is built upon treadmills, which simplify the design and implementation but also restrict the scope of possible experiments. This is largely due to the treadmill's single-dimensional movement and the lack of accommodation for natural or voluntary movement of the animal. In order to open up new possibilities for locomotion studies in rodents, this work introduces newly developed apparatus for locomotion research in rodents. The key concept is to allow maximal freedom of voluntary movement of the animal while providing forceful interaction when necessary. Advantages and challenges of the proposed machine over other existing designs are discussed. Design and implementation issues are presented and discussed, emphasizing their impact on free, voluntary, movement of the animal. A live-animal experiment was conducted to verify the design principles. Unconstrained natural movement of the animal was compared with movement with the overground robot attached. The compact, overground design and backdrivable implementation of this robot allow novel experiments that involve open-space, free (or interactive) locomotion of the animal.