Design, Simulation, and Testing of Laika, a Quadruped Robot with a Flexible Actuated Spine
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Walking quadruped robots face challenges in positioning their feet and lifting their legs during gait cycles over uneven terrain. Laika is a quadruped robot with a flexible, actuated spine designed to assist with foot movement and balance during these gaits. This paper presents the first set of hardware designs for Laika, a physical prototype of those designs, and tests in both hardware and simulations that show the prototype's capabilities. Laika's spine is a tensegrity structure, used for its advantages with weight and force distribution, and represents the first working prototype of a tensegrity spine in a quadruped robot. The spine bends by adjusting the lengths of the cables that separate its vertebrae, and twists using an actuated rotating vertebra at its center. Laika's current prototype has stiff legs, with only the spine in motion. This work shows the advantages of Laika's spine by demonstrating the spine lifting each of the robot's four feet, using specific combinations of bending and rotation movements. For each of the four lifting motions, data on foot positions are collected from both simulations and hardware experiments on the prototype. Simulation data on foot height lie within or close to the range of hardware experiment results, depending on direction of spine twist. Future work will combine actuated legs with Laika's spine, and compare the performance of a walking quadruped with and without the spine.
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