A Modified Robotic Rat to Study Rat-like Pitch and Yaw Movements

In this paper, we imitated rat-like typical motion primitives (such as yaw and pitch movements) using a modified multi-joint robotic rat. We developed a new robotic rat named WR-5M by optimally modifying the hardware system of the previous version. Using a kinematic analysis of the workspace of pitch and yaw movements, WR-5M was endowed with a larger movement range than the previous version. To assess the motion performance of WR-5M, we used pitch angle and pitch height to characterize the pitch maneuverability, and the yaw radius and yaw distance to characterize yaw maneuverability. After comparing with a rat, the extrema of the four proposed parameters demonstrated that the robot achieved a high-degree of similarity of extreme pitch and yaw gestures. Additionally, by imitating the whole motion process of four typical behavior patterns, WR-5M was able to implement similar pitch and yaw movements of the rat.