Development and Kinematic Accuracy Analysis of Supernumerary Robotic Limbs

This paper presents a supernumerary robotic limbs (SRLs), which have an additional four degree-of freedoms (DOF) robotic limb mounted on the waist of the wearer. In order to analyze the kinematic accuracy of the SRLs, this paper built the kinematic model and adjoint error model based on the Product of Exponential (POE) theory. For facilitating the parameter identification of the adjoint error model, this paper established a linear error model with only position measurement of end-effector. The experiment result verify the validity of the error model and it is enough precise for most practical manipulations. Meanwhile, comparing the kinematic accuracy of fixed base and floating base of SRLs, the results show that motion precision will be significant loss when the SRLs worn on the human body. This indicates that in the process of collaboration, SRLs may not be suitable for assigning tasks with high demands for motion accuracy.