Design Method of a Kangaroo Robot with High Power Legs and an Articulated Soft Tail

Abstract

In this paper, we focus on the kangaroo, which has powerful legs capable of jumping and a soft and strong tail. To incorporate these unique structure into a robot for utilization, we propose a design method that takes into account both the feasibility as a robot and the kangaroo-mimetic structure. Based on the kangaroo's musculoskeletal structure, we determine the structure of the robot that enables it to jump by analyzing the muscle arrangement and prior verification in simulation. Also, to realize a tail capable of body support, we use an articulated, elastic structure as a tail. In order to achieve both softness and high power output, the robot is driven by a direct-drive, high-power wire-winding mechanism, and weight of legs and the tail is reduced by placing motors in the torso. The developed kangaroo robot can jump with its hind legs, moving its tail, and supporting its body using its hind legs and tail.

Figures (24)

• Figure 1: Overview of the kangaroo robot.
• Figure 2: Design procedure for life-size kangaroo robot.
• Figure 3: Hind leg structure and typical muscles contributing to kangaroo leg movement.
• Figure 4: Simplified musculoskeletal structure of the leg.
• Figure 5: Trajectory of the stance phase. The blue broken line represents the robot's body to its legs, with the bent parts indicating the joints. From top to bottom, it represents the torso, thigh, lower leg, and footplate of the robot.