Johan Potgieter

Kinematics and Experiments of a Life-Sized Masticatory Robot for Characterizing Food Texture

A life-sized masticatory robot, which is intended to chew foods in a human way while the food properties are evaluated, of a 6RSS parallel mechanism is discussed in this paper. A robotic mechanism is proposed, and its kinematic parameters are defined according to the biomechanical findings and measurements of the human masticatory system. For a given mandibular trajectory to be tracked, the closed-form solution to inverse kinematics of the robot is found for joint actuations, whereas differential kinematics is derived in Jacobian matrices. Major features of the robot, including the motion control system, are presented. Experimental results for free chewing, soft-food chewing, and hard-food chewing are given where the foods are simulated by foam and hard objects, and crank actuations and driving torques (an indication of muscular activities) required are compared for the chewing of different foods.

Object-oriented knowledge representation and discovery of human chewing behaviours

Mastication is a complex process influenced by numerous factors including those associated with an individual and the ingested food. Human chewing behaviour can be characterised by measuring mandibular movements and muscular activities during a masticatory sequence or by measuring the particle size distribution and rheological characteristics of the swallowed food mass. To constructively understand the mastication process and assess the mastication performance, a formal description of the chewing behaviour is proposed in this paper. An object-oriented model is developed and described in Unified Modelling Language (UML). The chewing behaviour model is composed of three objects, one for the jaws physiological apparatus, one for the properties defining the mastication process and foods being chewed, and a further one for the association of the properties. A complete representation of the chewing behaviour is achieved by linking three object models via an additional class for chewing data that is collected experimentally. With the object model, the chewing behaviour is further instantiated by discovering knowledge hidden in the chewing database by data mining. A case study is presented to show the procedure of how the hidden knowledge is discovered and the data mining results are interpreted in the context of food science.

Bluetooth ubiquitous networks: seamlessly integrating humans and machines

The integration of humans and machines can be achieved using Bluetooth ubiquitous networks. Ideally, the interface between users and machines should be completely seamless and transparent. A user should not need to take any physical action to have a machine react to commands. A novel application area for Bluetooth communication technology is being developed in the Massey University Smart House project, in New Zealand. The creation of a Bluetooth ubiquitous network allows the house users to be tracked and monitored throughout the house. Their specific preferences or needs can automatically be taken care of by a control computer. This paper outlines and describes this seamless application.

3D scanning and printing skeletal tissues for anatomy education

Detailed anatomical models can be produced with consumer‐level 3D scanning and printing systems. 3D replication techniques are significant advances for anatomical education as they allow practitioners to more easily introduce diverse or numerous specimens into classrooms. Here we present a methodology for producing anatomical models in‐house, with the chondrocranium cartilage from a spiny dogfish (Squalus acanthias) and the skeleton of a cane toad (Rhinella marina) as case studies. 3D digital replicas were produced using two consumer‐level scanners and specimens were 3D‐printed with selective laser sintering. The fidelity of the two case study models was determined with respect to key anatomical features. Larger‐scale features of the dogfish chondrocranium and frog skeleton were all well‐resolved and distinct in the 3D digital models, and many finer‐scale features were also well‐resolved, but some more subtle features were absent from the digital models (e.g. endolymphatic foramina in chondrocranium). All characters identified in the digital chondrocranium could be identified in the subsequent 3D print; however, three characters in the 3D‐printed frog skeleton could not be clearly delimited (palatines, parasphenoid and pubis). Characters that were absent in the digital models or 3D prints had low‐relief in the original scanned specimen and represent a minor loss of fidelity. Our method description and case studies show that minimal equipment and training is needed to produce durable skeletal specimens. These technologies support the tailored production of models for specific classes or research aims.

Mechanism design and analysis of a wearable device for rehabilitation of temporomandibular disorder

A wearable device is proposed for the purpose of practical rehabilitation of temporomandibular disorder (TMD). The three-dimensional movement of the jaw is simplified as moving in the two-dimensional sagittal plane. The normal jaw motion is specified in terms of incisor trajectory and condylar trajectory, the former being used to synthesize the mechanism and the latter for the evaluation. A four-bar linkage is designed to meet the requirements, with adjustable links used for achieving a group of the trajectories. The device is symmetric about the middle sagittal plane of the skull and consists of two identical linkages, one at each side of the jaw and its kinematics is simulated in SimMechanics to evaluate both the device design and the man-machine interaction. Lastly, realistic evaluation is done with adding the compliant components in the hybrid system, where the human jaw is modeled by another planar linkage with special attention given to a TMJ that rotates and translates in space.

Matsuoka Neuronal Oscillator for Traffic Signal Control Using Agent-based Simulation

Matsuoka neuronal oscillator is proposed to control the traffic signals of an isolated four-phase signalized intersection. The oscillator is a model of central pattern generator (CPG) and has seen various applications in humanoid robots. Matsuoka oscillator was chosen for the traffic signal control because of its stable and predictable rhythmic outputs that exploit autonomously the dynamics of the road system. In this paper, the dynamics of Matsuoka oscillator was described in a set of first-order differential equations and simluated in an agent-based modelling environment. This novel signal control algorithm was validated in a Application Programming Interface (API) function by AIMSUN (Advanced Interactive Microscopic Simulator for Urban and Non-Urban Networks). The results were compared to the performance of the existing traffic system and have shown the potential capability of the proposed algorithm in reductions of vehicle delay time and queues.

Ovine automation: robotic brisket cutting

Purpose – The purpose of this paper is to provide details on implementation of inexpensive and accurate automation solution for performing brisket cutting while the sheep/lamb is hanging by forelegs.Design/methodology/approach – The system developed uses 6 Degree of freedom (DOF) industrial manipulator, custom build tool, sterilizer, and other off the shelf products to create a machine, all the parameters in the system are designed to ensure that the highest levels of safety and hygiene standards are met. The primary system has been developed for sheep/lamb.Findings – It is shown that the system developed enhanced both the productivity and quality of the process, while adhering to the hygiene standard in the meat processing plants.Research limitations/implications – The process of precise brisket can be very challenging; the system designed uses customised tools to provide a good model for the trajectory planning.Originality/value – The system developed uses statistical tools to calculate the correct traj...

Reconfigurable Manufacturing System for Agile Manufacturing

Abstract Manufacturing companies are facing three challenges: low cost production of product, high quality standard and rapid responsiveness to customer requirements. These three goals are equally important for the manufacturing companies who want to be competitive in the global economy. Reconfigurable Machining Systems, (RMS), facilitate the demand for mass producing custom products. Reconfigurable Automated Vision Inspection Systems, (RAVIS), go hand in hand with the machining systems as these products need to be checked and scanned in regular batches to ensure high quality standards. RMS and RAVIS are subsystems of Reconfigurable Manufacturing System which falls within the scope of Agile Manufacturing. Agile Manufacturing provides the ability to accomplish rapid changeover between manufacturing processes for different assemblies.

3D printing of fibre reinforced honeycomb structured composite materials

The paper presents the work on manufacturing and preliminary characterisation of fibre reinforced composite honeycomb structured composites by 3D printing. The capabilities and limitations of the processing are discussed. The work aims to compare the effectiveness of reinforcement using specimens of similar dimensions produced on the same machine and characterise them. Initially, tensile performance of unprinted fibre and printed fibre has been evaluated. Challenges associated with the testing of the printed specimens are addressed. Bend testing will follow to assess the performance as a composite structure to assess the interaction between fibre, matrix and core. Continuing work is planned to compare the effect of other parameters such as fill pattern and fill density to assess their effect on the composite.

Reconfigurable Mechatronic Robotic Plug-and-Play Controller

In today’s manufacturing community, flexible manufacturing systems (FMS) are becoming important. There is a global trend towards flexible manufacturing systems with an increasing number of countr ies competing for a share of the world market. FMS are increasingly required for companies to meet the demand for high quality, reasonably priced products. FMS allow a manufacturer to quickly change processes or operations to produce any product, at any time, while striving to keep the processes economical. To remain competitive companies should be replacing or upgrading old, obsolete methods, processes, and systems with the latest advances in manufacturing technology. This competition within the manufacturing industry has led to a focus on producing high quality parts quickly and accurately. The quality of products, along with the increased productivity necessary to compete globally, has led more and more manufacturers to introduce advanced manufacturing technologies in their factories. In order for these advanced manufacturing technologies to be accepted by manufacturing companies, they need to be able to implement the new technologies and their processes as quickly as possible so as to keep manufacturing down-time to a minimum. This allows the manufacturer to respond quickly and with increased flexibility to market needs. Such is the need for FMS.