Experimental verification of workspace and mouth-opening movement of a redundantly actuated humanoid chewing robot

Purpose – This paper aims to verify the workspace and movement performance of a redundantly actuated humanoid chewing robot. Design/methodology/approach – A redundantly actuated humanoid chewing robot with 6-PUS linkages and two higher kinematic pairs (HKPs) is introduced. The design of HKPs is specified by mimicking the temporomandibular joint (TMJ) structure obtained through a computed tomography scan of the mastication system. The border movement, mouth-opening trajectory and velocity of subjects’ lower incisor point are measured by using the mandibular kinesiograph. Based on the kinematics, the envelope of the workspace is analyzed. The workspace and mouth-opening movement experiments are carried out. The border movement of the lower incisor point is measured. The mouth-opening trajectory is planned and tested on the chewing robot. Findings – Comparing with measurement results of border movement and mouth-opening movement of human, it is shown that the humanoid chewing robot can meet the workspace requirements and is able to perform mouth-opening movement like human-beings. Practical implications – The chewing robot is designed to reproduce human jaw movements and application in test of dental components and materials or evaluation of food textural properties. Originality/value – The chewing robot is inspired by the mastication system which itself is mechanically redundant because of the TMJ and more muscles than required. The novel spatial redundantly actuated chewing robot is the first of this kind with two HKPs to mimic the human TMJ and is a higher fidelity mechanism.