Prototyping a robotic dental testing simulator

Abstract A parallel robot based on the Stewart platform is being developed to simulate jaw motion and investigate its effect on jaw function to test the wearing away of dental components such as individual teeth, crowns, bridges, full set of dentures, and implant-supported over-dentures by controlling chewing motion. The current paper only describes the comparison between an alternative configuration proposed by Xu and the Stewart platform configuration. The Stewart platform was chosen as an ideal structure for simulating human mastication as it is easily assembled, has high rigidity, high load-carrying capacity, and accurate positioning capability. The kinematics and singularities of the Stewart platform have been analysed and software developed to (a) test the control algorithms/strategy of muscle movement for the six degree of freedom of mastication cycle and (b) simulate and observe various design options to be able to make the best judgement in product development. The human replica skull has been analysed and reverse engineered with further simplification before integration with the Stewart platform computer-aided design (CAD) to develop the robotic dental testing simulator. Assembly modelling of the reproduced skull was critically analysed for good occlusion in CAD environment. A pulse-width modulation (PWM) circuit plus interface was built to control position and speed of the chosen actuators. A computer numerical control (CNC) machine and wire-electro-discharge machining (wire EDM) were used to manufacture the critical parts such as lower mandible, upper maxilla, and universal joints.

[1]  E F Fichter,et al.  A Stewart Platform- Based Manipulator: General Theory and Practical Construction , 1986 .

[2]  Ilian A. Bonev.  The true origins of parallel robots , 2003 .

[3]  Weiliang Xu,et al.  Choosing new ways to chew: a robotic model of the human masticatory system for reproducing chewing behaviors , 2005, IEEE Robotics & Automation Magazine.

[4]  Weiliang Xu,et al.  Jaw mechanism modeling and simulation , 2005 .

[5]  Boris Mayer St-Onge,et al.  Singularity Analysis and Representation of Spatial Six-Dof Parallel Manipulators , 1996 .

[6]  J. Robert Kelly,et al.  CERAMICS IN RESTORATIVE AND PROSTHETIC DENTISTRY 1 , 1997 .

[7]  R. Ritchie,et al.  On the in vitro Fatigue Behavior of Human Dentin: Effect of Mean Stress , 2004, Journal of dental research.

[8]  D. Stewart.  A Platform with Six Degrees of Freedom , 1965 .

[9]  J. P. Lund,et al.  Influence of age on adaptability of human mastication. , 2004, Journal of Neurophysiology.

[10]  V. Thompson,et al.  Dental ceramics and the molar crown testing ground. , 2004, Journal of applied oral science : revista FOB.

[11]  R DeLong,et al.  Development of an Artificial Oral Environment for the Testing of Dental Restoratives: Bi-axial Force and Movement Control , 1983, Journal of dental research.

[12]  H. Fischer,et al.  R-Curve Behavior of Dental Ceramic Materials , 2002, Journal of dental research.

[13]  Linda Wang,et al.  Mechanical properties of dental restorative materials: relative contribution of laboratory tests. , 2003, Journal of applied oral science : revista FOB.

[14]  Clément Gosselin,et al.  Singularity analysis and representation of planar parallel manipulators , 1992, Robotics Auton. Syst..

[15]  Jean-Pierre Merlet.  Singular Configurations of Parallel Manipulators and Grassmann Geometry , 1989, Int. J. Robotics Res..

[16]  Kazem Alemzadeh.  Prototyping a dental mastication robot simulator , 2006 .

[17]  K. H. Hunt,et al.  Kinematic geometry of mechanisms , 1978 .

[18]  Bhaskar Dasgupta,et al.  Singularity-free path planning for the Stewart platform manipulator , 1998 .

[19]  H Fischer,et al.  Nondestructive estimation of the strength of dental ceramic materials. , 2001, Dental materials : official publication of the Academy of Dental Materials.