6-DOF Chewing Virtual Prototype Design

Masticatory robots are used for simulating human chewing movement. Given themandiblular movement trajectory equations, they can restore human chewingmovements directly. They are now widely used in clinical medicine and food testing.The development masticatory robots are currently able to simulate human jawmovement perfectly in performance. But there are significant flaws on shape andfidelity in robots.In this thesis, analysing the organizational structure about physiological andphysical characteristics of masticatory system, it establishes mechanical system of6-DOF masticatory virtual prototype model by mechanical virtual technology. The mainstudy includes the following aspects.1．Analysing the organizational structure about physiological characteristic ofmandible, masticatory muscles, temporomandibular joint and ligament, it establishes adigital masticatory system. In order to get simplified three-dimensional CAD model ofmandible, it can reconstruct three-dimensional mandible by applying medical imageprocessing software and reverse engineering software. Creating three-dimensionaldigital masticatory muscles model and physiologically-fitted motion pairs is based onanatomy about the characteristics of the masticatory muscles and temporomandibularjoint. And then it gets the mechanical model of masticatory system that conforms withthe physiological property of human chewing movements.2． Establishing the function relationship between the masticatory muscles’telescopic length and incisor trajector, it can carry out trajectory planning of themechanical model. Given the mandiblular movement trajectory equations, it simulatesthe human chewing movements by using ADMAS and MATLAB/Simulink. Then itanalyzes the simulation graphs so as to provide the reference for6-DOF mechanicalsystem.3．Calculated the driving forces are the basis of6-DOF mechanical system.Especially considering the reliability of mechanical system, it must calculate the drivingforce of each drive rod under the maximum masticatory force. The design of the actuator is the key of the mechanical system. Taking into account the mechanicalsystem of6-DOF masticatory virtual prototype model’s design requirements andworking conditions, it determines the ball screw as a drive rod of the mechanical system,because the working stroke, driving force and motion accuracy fit the design of themechanical system.4．Position analysis which includes forward and inverse solutions of its positions,is the basis of the performance analysis and control system. In the final analysis itexpresses the input-output function relations between drive rods and mandible.6-DOFmechanical system’s performance analysis includes workspace analysis and erroranalysis. The workspace analysis mainly analyzes the limitations of the sphericalpairs’ angle. Error analysis of mechanical system is the basis of error compensation. Itcan truly simulate the human jaw movements by using software method to compensatethe error of the6-DOF mechanical system.