Wang Cheng-tao

Sustainability in manufacturing: Recovery of resources in product and material cycles

Global Framework.- Life Cycle Engineering and Management.- Product Development.- Processes and Tools for Disassembly.- Planning for Remanufacturing and Recycling.- Enabling for Sustainability in Engineering.- Roadmap.

Image guided oral implantology and its application in the placement of zygoma implants

The application of zygoma implants proposes a successful treatment for functional reconstruction of maxillary defects. However, the placement of zygoma implants is not without risk due to anatomically complex operation sites. Aiming at minimizing the risks and improving the precision of the surgery, an image guided oral implantology system (IGOIS) is presented in this study to transfer the preoperative plan accurately to the operating theatre. The principle of IGOIS is introduced in detail, including the framework, 3D-reconstruction, preoperative planning, registration, and the motion tracking algorithm. The phantom experiment shows that fiducial registration error (FRE) and TRE (target registration error) of IGOIS are, respectively, 1.12mm and 1.35mm. With respect to the overall accuracy, the average distance deviations at the coronal and apical point of the implant are, respectively, 1.36+/-0.59mm and 1.57+/-0.59mm, while average angle deviation between the axes of the planned and the actual implant is 4.1 degrees +/-0.9 degrees . A clinical report for a patient with a severely atrophic maxilla demonstrates that the major advantage of this computer-aided navigation technology lies in its accuracy, reliability, and flexibility.

An integrated on-line oil analysis method for condition monitoring

An on-line oil monitoring system offers a suitable solution to the practical problems encountered in monitoring the conditions of machinery equipment. The objective of this paper is to present a systematic method for analysing wear particles in the lubricant used in a diesel engine, in a laboratory setting. An integrated on-line oil monitoring system, which combines an inductive transducer with a fibre optic transducer, was developed to primitive design stage and some experiments have been done. The inductance transducer, whose operation is based on an inductive measurement technique, can detect large ferrous and non-ferrous wear debris. A particles material properties reflect its origin, and the frequency can be used for estimating wear particle size. The fibre optic transducer can detect small particles and is used for inspection of oil contamination levels. The integrated system combines the virtues of two measurement methods, extends the detection range and meaningfully improves the reliability of oil monitoring. So it has great promise and there are prospects for application as soon as the solutions to certain problems are found.

Computer-aided oral implantology: methods and applications.

Aiming at transferring the preoperative planning information to the patient in oral implantology, this study presents an image guided oral implant system (IGOIS), which integrates 3D medical modelling, preoperative surgical planning and intraoperative tracking into a dental navigation system. With the fabrication of a tooth-supported polymer resin template, a non-invasive point-based registration method through ICP algorithm is explicitly discussed. The experimental test shows that deviation between planned and achieved position of the implant is 1.2 mm at the tip and 1.3 mm at the head, which thereby demonstrates that IGOIS can reach a level of accuracy where further clinical developments are feasible.

A pilot application of image-guided navigation system in mandibular angle reduction surgery

Mandibular angle reduction is the one of the most popular methods applied toward correcting the prominent mandibular angle(PMA) in Asian countries. The purpose of this study is to apply a computer-aided surgical 3D planning and image-guided navigation system (Navi-CMFS) in mandibular angle reduction surgery, aiming at improving the surgical accuracy, minimizing surgical risks and optimizing clinical results.

An integrated surgical planning and virtual training system using a force feedback haptic device for dental implant surgery

The application of dental implants proposes a successful treatment both partially and fully edentulous patients. However, the placement of implants is not without risk due to anatomically complex operation sites in the cranio-maxillofacial region. Therefore, in the field of oral implantology, there is a trend towards computer-aided implant surgery. In this study, an integrated surgical planning and virtual training system is presented. With the introduction of DLL (Dynamic Link Libraries) and some well-known free, open source software libraries such as VTK, ITK, and QT, a modular software named CAPPOIS (Computer Assisted Preoperative Planning for Oral Implant Surgery) was developed for preoperative planning, including medical image importing, image segmentation and 3D-Reconstruction, 2D/3D geometrical measurements, optimization design of the position and orientation of oral implants, etc. Then, the following virtual surgical training system is developed based on the force feedback haptic device, i.e., Omega.3, and the software toolkit of CHAI3D. With the use of this system, the resulting data of the preoperative planning can be transferred, and surgical simulation of the plan can be vividly realized. In this way, the surgeon can grasp the feel of osteotomy procedure, gain experience and therefore improve his skills during the actual dental implant surgery. This pilot study proves helpful for the inexperienced surgeons; however, more clinical cases will be conducted to demonstrate its feasibility and reliability.

A computer-aided oral implantology system

In order to optimize the position of oral implants and make the best possible use of the available bone volume in the oral implant therapy, a computer-aided oral implantology system including the framework, modeling, preoperative 3D planning, registration method, optical tracking systems and real-time navigation is introduced in this study. With the support of this system, the precision achieved in the planning phase can be transferred to the patient so that the accuracy of the oral implant surgery is improved

End-of-life vehicle recycling based on disassembly

The end-of-life vehicle recycling was studied based on the disassembly. The end-of-life recycling and the disassembly were reviewed and discussed. A disassembly experiment of an end-of-life engine was carried out, which strictly recorded the process of dismantling. Based on the results, a model of the end-of-life recycling was presented. In this model, the end-of-life parts were classified by three ways which included to recycle directly, to recycle after remanufacturing and to discard. By using this model, the dismantling efficiency and the recycling rate can be improved. Also, it obtains a good result after used in a dismantling factory.

Simulation and Evaluation of a Bone Sawing Procedure for Orthognathic Surgery Based on an Experimental Force Model

Bone sawing is widely used in orthognathic surgery to correct maxillary deformities. Successful execution of bone sawing requires a high level of dexterity and experience. A virtual reality (VR) surgical simulator can provide a safe, cost-effective, and repeatable training method. In this study, we developed a VR training simulator with haptic functions to simulate bone-sawing force, which was generated by the experimental force model. Ten human skulls were obtained in this study for the determination of surgical bone-sawing force. Using a 5-DOF machining center and a micro-reciprocating saw, bone specimens with different bone density were sawed at different feed rates (20, 40, and 60 mm/min) and spindle speeds (9800, 11,200 and 12,600 cycles per minute). The sawing forces were recorded with a piezoelectric dynamometer and a signal acquisition system. Linear correlation analysis of all experimental data indicates that there were significant positive linear correlations between bone-sawing force and bone density and tool feed rate and a moderate negative linear correlation with tool spindle rate. By performing multiple regression analysis, the prediction models for the bone-sawing procedure were determined. By employing Omega.6 as a haptic device, a medical simulator for the Lefort I osteotomy was developed based on an experimental force model. Comparison of the force-time curve acquired through experiments and the curve computed from the simulator indicate that the obtained forces based on the experimental force model and the acquired data had the same trend for the bone-sawing procedure of orthognathic surgery.

Real-time Navigation in Orthognathic Surgery

In order to realize real-time navigation in orthognathic surgery, i.e. to realize real-time tracking the pose (position and rotation) of the patient and the instruments, we developed a 3D osteotomy simulation and real-time navigation system (3D OsteoSim&Nav) for the first time in China. After the preoperative 3D simulation, system matches the markers on 3D model to the markers in surgical patients site to complete the registration. Then the system real-time tracks the pose of the surgical instruments and patient, and real-time offset the site change of the patient. In this way the doctor can accurately operate according to the simulative results. The experimental results show that this navigation system works well and improves the surgical precision