An Active and Dexterous Bionic Torso for a Quadruped Robot^*

The torso of quadruped mammals serves as a robust foundation for their bodies, enabling a diverse array of agile and intricate movements. However, current quadruped robots cannot match the extensive range of motion exhibited by biological torsos while also serving a load-bearing role. Therefore, this paper presents an active bionic torso that emulates the quadrupedal animal's spinal column and associated muscular structure. This innovative torso can mimic animal torsos movements, including flexing, extending, lateral bending, and axial rotation. A thorough analysis of the torso's kinetic, workspace, and structural dynamics has been conducted. This proposed torso boasts a considerable load-bearing capacity and can support a load that exceeds its weight tenfold. The passive spring incorporated into the bionic torso emulates the intervertebral discs' shock-absorbing and load-bearing functions. Additionally, this paper documents the development of a quadrupedal robot fitted with the proposed bionic torso, demonstrating the torso's mobility in a real-world application.