Robophysics-inspired biology experiments to study gait control for obstacle negotiation in canines

Determining strategies for stable and economical locomotion in robots in complex environments can be inspired by biology, and in turn, results from robotic locomotion can inspire a unique approach to studying the biomechanics of how animals overcome obstacles. We explore how gait types and environment structure influence the way quadrupedal animals, here dogs, negotiate obstacles. Prior research shows trajectories of stable locomotion emerge based on direct leg-obstacle interactions in a quadrupedal robot as it moves over a regular array of domed obstacles. Considering a dog's flexibility and tradeoffs between desired gait, navigation, and energy expenditure, we hypothesized that in a similar array, dogs would change gait parameters including duty factor, limb phase, stride length, as well as direction of locomotion. These factors are compared in 11 dogs, by adjusting the spacing between the obstacles to 20% greater than and less than each dog's natural trotting step length. Results indicate that dogs will focus on obstacle avoidance by changing gait parameters with both minor continuous adjustments (values of duty factor), and large infrequent adjustments (jumping over obstacles), in response to variation in the spacing size between obstacles.