Development of a Biomimetic Masticating Robot for Food Texture Analysis

Assessing the food texture via mastication is important for advancing knowledge of food properties so as to develop favorable and healthy food products. Oral processing of food by robots can enable an in vitro assessment of food texture by simulating human mastication objectively. In this study, a chewing robot is developed to mimic the rhythmic motion of the molars to enable controllable chewing kinematics and a biomimetic oral environment. The robotic chewing is realized using a 3 degree-of-freedom (DOF) linkage mechanism, which recreates the molar grinding movement based on molar trajectories and chewing cycle durations previously reported in the literature. Moreover, a soft pneumatically actuated cavity is developed to provide a space to contain and reposition the food between occlusions. In order to regulate the robotic chewing having variable molar trajectories and chewing durations, the mathematical relationship of the linkage's actuators and molar movements is investigated for the purpose of motion analysis and control. Accordingly, the design of the robot in terms of linkage, oral cavity and mechatronics system is performed. The built robot is validated by tracing a planned variable molar trajectory while chewing peanuts. The performance of robot chewing is validated by demonstrating the ability of the robot to chew the peanuts similar to that by human through comparison of peanut particle size distributions (PSDs) and particle median size diameters.