Towards Jumping Locomotion for Quadruped Robots on the Moon

Jumping locomotion has the potential to enable legged robots to overcome obstacles and travel efficiently on low-gravity celestial bodies. We present how the 22 kg quadruped robot SpaceBok exploits lunar gravity conditions to perform energy-efficient jumps. The robot achieves repetitive, vertical jumps of more than 0.9m meter and powerful single leaps of up to 1.3m. We present the implementation of a reaction wheel, which allows for control of the robots pitch orientation during the flight phase. We also demonstrate the implementation of a parallel elasticity in the legs providing the capability of temporarily storing and reusing energy during jumping. The jumping and attitude controller are subsequently presented. Finally, we analyze the energetics of the system and show that jumping with the integrated elasticity significantly reduces energy consumption compared to non-elastic jumps.