Staff Profiles

Associate Professor Jayantha KATUPITIYA

Qualifications

Employment

Visiting Appointments

Professional Societies

• The Institution of Electronic and Electrical Engineers, Member
• The American Society of Mechanical Engineers, Member

Teaching Areas

• C++ for Mechatronics
• Discrete-time Control Systems
• Microprocessor Applications for Mechatronics
• Modelling and Control of Mechatronic Systems

Research Interests

Agricultural Robotics

The research in this area is directed at automating large scale ground vehicles that operate on the agricultural fields and their autonomous navigation to conform to traversing specifications. They are, in general, articulated vehicle systems, in which a large tractor is providing propulsion and steering, and large implements are passively dragged behind. The control inputs to such a system are inadequate to guide the implements to follow a specified path. The research is aimed at providing the necessary control inputs at the implements to enable the precision autonomous navigation of the entire system. Research includes: i) the kinematic modelling of articulated systems taking into account the lateral and longitudinal wheels slips, ii) determination of force inputs using approximate dynamic models and the kinematic system responses, and iii) the design of controllers.

Cooperative Control of Heterogeneous Autonomous Vehicles

The research aims to achieve asynchronous cooperative control between one air vehicle and a fleet of ground vehicles. The goal is to navigate the ground vehicles to concurrently carry out a single task or to carry out a spatially distributed set of sub tasks that forms parts of a major task, under the supervision and coordination of the aerial vehicle. The fleet of ground vehicles are assumed to be distributed at different locations. In the case of a single task, the ground vehicles are assumed to have complementary capabilities. In the case of multiple tasks the ground vehicles may possess identical or complementary task execution capabilities. A practical scenario is bush fire containment. The research issues involve task identification and localisation through sensing carried out by the aerial vehicle, task scheduling, terrain mapping using the aerial vehicle, path planning for ground vehicles using terrain data and autonomous navigation of ground vehicles to their scheduled destinations. In particular, the research aims at developing a software architecture for the cooperative control of the group of vehicles and the development of methodologies for the direct navigation and control of ground vehicles under the continuous and direct command of aerial vehicles without the use of GPS data.

3-D Terrain Mapping

Methodologies are developed through fusion of multi-layered laser scans and visual images to generate a 3-D terrain map that can be used by crawling and wall climbing robots. A 7-degrees of freedom fully self contained two legged wall climbing robot has small laser range finders and miniature cameras mounted on its feet. The data gathered using the two types of sensors are fused in a special algorithm to build a map of the terrain with significant time efficiency. The 3-D surface patches identified through the procedure are then integrated to make a global 3-D map.

Mechanical Machining of Micro-lenses on Optical Fibres

It is well known that the light coupling efficiency of optical fibres can be enhanced by fabricating micro-lenses at the tips of optical fibres. This research investigates high-precision mechanical means of fabricating such lenses. Currently, the research has progressed well and purely mechanical means are used to effect efficient ductile mode machining of Silica to produce these lenses. The research project also covers mechanical means of polishing the machined lenses to further improve the surface quality so that they are suitable for optics related applications. Some example lenses machined at the tips of optical fibres are shown here.

Professional Interests and Consulting

• Consultant to industry through Mechlab/NewSouth Global in areas of industrial automation, real-time control software, microprocessor applications, robotics and autonomous systems for agricultural automation
• Agricultural robotics

Selected Publications

Book

• KATUPITIYA J and BENTLEY K, Interfacing with C++: Programming Real-world Applications, Springer-Verlag, Berlin, March (2006).

Selected Journal Papers

• DE SCHUTTER J, BRUYNINCKX H, DUTHRE S, DE GEETER J, KATUPITIYA J, DEMAY S and LEFEBVRE T, "Estimating first-order geometric parameters and monitoring contact transmissions during force-controlled compliant motion", The International Journal or Robotics Research, Vol 18(12), pp 1161-1184, December (1999).
• CHUA A, KATUPITIYA J and DE SCHUTTER J, "Random execution of a set of contacts to solve the grasping and contact uncertainties in robotic tasks", The Journal of Robotica, Vol 19(2), pp 199-207, March (2001).
• LEE SH, KIM IS and KATUPITIYA J, "A fuzzy-logic controller for an electrically driven steering system for a motorcar", International Journal of Korean Society of Mechanical Engineers, Vol16 (8), pp 1039-1052 (2002).
• GHARBIA Y and KATUPITIYA J, "Loose abrasive blasting as an alternative to slurry polishing of optical fibre end faces", International Journal of Machine Tools and Manufacture, Vol 43, pp 1413-1418 (2003).
• GHARBIA Y and KATUPITIYA J, "Experimental determination of optimum parameters for nano-grinding of optical fibre end faces", International Journal of Machine Tools and Manufacture, Vol 44, pp 725-731 (2004).
• ILIC S, NINIC D, STARK H, TORDON M and KATUPITIYA J, "Effect of road conditions on the fatigue life of an automatic transmission output shaft", Proc. Instn Mech. Engrs, Part D, Journal of Automobile Engineering (2005).
• MILTON G, GHARBIA Y and KATUPITIYA J, "Mechanical fabrication of micro-lenses on optical fibre end faces", SPIE Journal of Optical Engineering, Vol 44(12), pp 123402/1-8, December (2005).