The purpose of this project is researching flexible tensegrity spines for walking robots. Robots with flexible spines have many potential advantages over those with rigid body structures. Motion between a robot’s hips and shoulders could allow for more complex and efficient locomotion for quadrupeds, as well as greater ability to traverse unknown terrain and interact with unknown environments while keeping stable and safe. This project, the walking quadrupeds is designed to utilize a tensegrity spine as its backbone.

Walking quadruped robots face challenges in positioning their feet and lifting their legs during gait cycles over uneven terrain. The robot is under development as a quadruped with a flexible, actuated spine designed to assist with foot movement and balance during these gaits. This project will be interested in the first set of hardware designs for the spine of the robot, a physical prototype of those designs, and tests in both hardware and simulations that show the prototype’s capabilities. Robot’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 for a quadruped robot.

This project will do care about the current prototype of robot which will has stiff legs attached to the spine, and it will be used as a test setup for evaluation of the spine itself. This project will shows the advantages of Robot’s spine by demonstrating the spine lifting each of the robot’s four feet, both as a form of balancing and as a precursor for a walking gait. These foot motions, using specific combinations of bending and rotation movements of the spine, are measured in both simulation and hardware experiments. Hardware data are used to calibrate the simulations, such that the simulations can be used for control of balancing or gait cycles. Also, we can work with attach actuated legs to robot’s spine, and examine balancing and gait cycles when combined with leg movements.

This project presents a study on form-finding of four-stage class one self-equilibrated spine biotensegrity models. Advantageous features such as slenderness and natural curvature of the human spine, as well as the stabilizing network that consists of the spinal column and muscles, we will model and incorporate in the mathematical formulation of the spine biotensegrity models. Form-finding analysis, which involved determination of independent self-equilibrium stress modes using generalized inverse and their linear combination, was carried out. Form-finding strategy for searching the self-equilibrated models was studied through two approaches: application of various combinations of (1) twist angles and (2) nodal coordinates.

Most traditional robotic mechanisms feature inelastic joints that are unable to robustly handle large deformations and off-axis moments. As a result, the applied loads are transferred rigidly throughout the entire structure. The disadvantage of this approach is that the exerted leverage is magnified at each subsequent joint possibly damaging the mechanism. In this project, we will work on two lightweight, elastic, bio-inspired tensegrity robotic mechanism adapted from prior static models which mitigate this danger while improving their mechanism’s functionality.