Impedance posture control of robot manipulators using Euler parameters

In the robotic literature the resolved acceleration control based on vector analysis is often used for both position and posture control. Since the posture or orientation is not a vector quantity, the simple difference of the vector value of the current posture and that of the desired posture does not have any physical meaning through the convergence of the error can be analyzed based on the difference locally. In this paper we introduce Euler parameters (quaternion or spinor) as a representation of the error of the orientation, and we apply the parametrization to an impedance control of the posture control of robot manipulators. The properties of the impedance are analyzed