SPIDAR's Leg-Mounted Rotors Spin to Loft It Into the Air for a Near 10-Minute Flight Time

Researchers at the University of Tokyo's departments of mechanical engineering and mechano-infomatics have come together to build a flying, robotic SPIDAR — a quadrupedal robot that's at home on the ground as well as in the air.

"Multimodal locomotion capability is an emerging topic in [the] robotics field, and various novel mobile robots have been developed to enable the maneuvering in both terrestrial and aerial domains," the research team explains. "Among these hybrid robots, several state-of-the-art bipedal robots enable the complex walking motion which is interlaced with flying. These robots are also desired to have the manipulation ability; however, it is difficult for the current forms to keep stability with the joint motion in mid-air due to the centralized rotor arrangement."

That's where SPIDAR comes in. Described by the team as a spherically vectorable and distributed rotor-assisted air-ground amphibious quadruped robot, which is from where the somewhat torturous backronym is generated, the project aims to create a spider-inspired robotics platform that can hop into the air and start flying.

Brought to our attention by IEEE Spectrum, the SPIDAR prototype is made up of four gangly limbs split into two segments. Each of the two segments has a pair of rotor blades attached, which can roll around the limb to vector their thrust. Even when not in flight mode, the robot relies on the rotors to lift its bulk; disable them, and it goes crashing to the ground.

The project has some way to go yet, however. While the team describes the machine as "amphibious" the current prototype not is proofed against water ingress; the test platform also proved somewhat shaky in use, and its runtime limited to a little under ten minutes of flight or roughly double that on foot.

"To improve stability," the researchers suggest, "the rotor thrust should be directly used in the joint position control to replace the current simple PD control. Furthermore, the gait planning should be also robust against the drift by adding a feedback loop. Last but not least, the dynamic walking and the aerial manipulation will be investigated to enhance the versatility of this robot in both maneuvering and manipulation."

A preprint of the team's work is available on Cornell's arXiv server under open-access terms.