Design and Motion Control Strategy of a Bio-Inspired Jumping Robot for Aerial Rod-Hooking

Inspired by the jumping behavior of cassowary animals, this research proposes a ledge-grasping robot that is specifically capable of exploring vertical jumping motion patterns; for example, the robot launches from the ground and then grasps an object on the upper vertical wall. The motion process is divided into four phases: Squat Phase, Launch Phase, Transition Phase, and Landing Phase. The analysis is carried out by investigating the dynamic effects of the various operating parameters and phase switching conditions so that the robot can jump optimally at any target altitude. The motion trajectory planning is integrated with a virtual impedance control algorithm implemented on the BLDC motor as the joint actuator. In addition, the incorporation of Quasi-Direct-Drive (QDD) actuators facilitates smooth transitions between motion phases and improves energy accumulation efficiency. Experimental results demonstrate that the robot's motion gait effectively mimics the natural movement of a cassowary. The robot achieved a jump height of 0.34 m, a jump agility of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1.7 ~\mathrm{m} / \mathrm{s}$</tex>, a cost of transport (COT) of 2.72, and successfully grasped a target rod in mid-air. Furthermore, a comparative analysis with similar existing robots was conducted to study the design performance factors more widely, based on the respective results of vertical jump agility and COT.