Development of a dexterous cable driven spine mechanism for humanoid robots

In order to achieve more vivid human-like motion, a 3-DOF spine mechanism is developed. Two degrees of freedom (pitch and roll) are driven by three cables and the other one (yaw) is driven by gear and pulley. The mechanism is light-weighted and is capable of sustaining heavy load. Kinematics analysis is used to calculate the length change of the three cables while bending the spine mechanism. In spite of the accurate cable length control, the spine structure might still vibrate. To deal with this problem, the virtual work model method is proposed to compensate the three cable forces. In this way, the whole spine structure can act firmly. The performance of the proposed spine mechanism is justified with the simulations and experiments.