Dario J. Toncich

Integration of production planning, project management and logistics systems for supply chain management

The objective of this research was to develop an integrated framework to handle application modules in enterprise resource planning (ERP) and supply chain management (SCM) systems that traditionally needs to be interfaced on a case-by-case basis. This paper presents a framework integrating various modules in both systems, for planning, control and execution of materials, resources and operations. The framework enables planning and execution over a range of areas, from flow to project-based manufacturing and distribution from suppliers to customers. This document presents the conceptual framework development along with algorithms for scheduling paths, and illustrated numerical examples in the supply chain environment. The numerical evaluation of scheduling paths and planning of components, in the integrated networks, shows that the developed framework could cater for ERP/SCM application modules. The framework also facilitates simultaneous planning of many components, and eliminates the need for separate modules in ERPSCM systems. It enhances planning, control and execution, and simplifies the vendor follow-up system by integrating supplier components into the integrated network. The framework therefore becomes a new production planning (PP) module in integrated ERP/SCM systems and can provide links to other manufacturing philosophies, such as just-in-time (JIT).

Development of engineering structures for scheduling and control of aircraft maintenance

This paper documents research and development that were undertaken as collaboration between the Industrial Research Institute of Swinburne University of Technology (IRIS), Armor Pty Ltd and QANTAS. The objective of the research was to investigate the application of a unitary software structure, composed of the critical path method (CPM), materials requirements planning (MRP) and production activity control (PAC) techniques, to the management of large‐scale maintenance activities (specifically aircraft maintenance). This structure had previously been applied to the manufacturing (i.e. assembly) process but the maintenance problem posed significant new challenges. First, there was the issue of generating a disassembly structure, and second, the reconciliation of demands arising from non‐serviceable components. This paper documents the implementation of the structure and the methods that were used to validate its functionality on a test‐case application (i.e. aircraft maintenance problem).

A new type of machine control system to replace traditional CNC

This paper discusses the rationale behind a new form of machine tool control system which has been developed at the Key Centre for Computer Integrated Manufacture (CIM Centre) in Melbourne Australia. The new control system is based upon standard computer hardware and is intended as a replacement for computer numerical control (CNC), which has severe limitations in the CIM environment. The paper also outlines the new CIM possibilities which are now available as a result of this development.

Application of DSP technology to closed-position-loop servo drive systems

The objective of this paper is to demonstrate how digital signal processor (DSP) technology can be applied to servo motor control in order to generate closed-position-loop servo drives that can be applied in advanced manufacturing technology applications such as robotics, CNC and other machine positioning systems.Neither the DSP nor intelligent servo controls are new technologies in their own right. However, it is the combination of the two which has been innovatively applied at the Swinburne University of Technology (Hawthorn, Victoria, Australia) in order to generate a system which has considerable potential in terms of redesigning computer controlled production equipment through a distributed control architecture. The resulting technology has been entitled CIM-Drive and has been commercialised by the Softronics company in Australia.The critical factor in designing an intelligent servo system is the provision of a real-time local area network that can be used for inter-servo communication and for supervisory control. A relatively simple networking scheme (entitled “Softnet”) was developed during the course of the research and is documented herein. A number of newer, commercially available alternatives such as the CAN-Bus, Field-Bus and LON bus are also highlighted in this paper to show the current development path being pursued at the CIM Centre.

Hybrid FMS control architectures based on holonic principles

The escalation in processor technologies and the corresponding reduction in costs have enabled alternative FMS control architectures to be developed without the restrictions of “fixed machine controller boundaries”. These new architectures can be based upon the use of intelligent servo axes, which are desccribed in this article, as flexible numerical control (FNC). In current parlance, the FNC is a “part movement holon” within a manufacturing cell. The control architectures that can be derived from the FNC concept are referred to as hybrid architectures and share the emerging attributes of holonics. This article details the problems that arise in the scheduling and control of FMSs in the light of hybrid control architectures. A number of traditional scheduling approaches have been devised to cope with the scheduling of parts to discrete machines, but the problem here is to ascribe the processing (machining) of part features to axis groups. This article documents how two research programs, undertaken at the CIM Centre at Swinburne University of Technology in Hawthorn, Victoria, Australia, have endeavored to address the problem of hybrid architectures and their associated scheduling.

Non-contact inspection for the detection of internal surface defects in hollow cylindrical work-pieces

The objective of this paper is to document part of a collaborative research program undertaken by the Centre for Computer Integrated Manufacture (CIM Centre) at Swinburne University of Technology in Hawthorn, Victoria, Australia and Australian Defence Industries (ADI) Ltd in the field of “non-contact inspection”. This research program is one of two collaborative programs between the CIM Centre and ADI Ltd, related to inspecting the quality of components in an automated fashion, without the use of contacting sensors.There are a number of techniques currently being investigated at the CIM Centre, including lasers, vision, acoustic emission and X-ray based methods. This particular paper focuses on the research work undertaken by the first author in the detection of internal surface defects in forged, hollow cylindrical workpieces. The case study presented for consideration and discussion herein is related to the detection of cavity defects in forged pressure vessels. The paper provides a background into the range of alternative non-contact inspection techniques that are available (including lasers, ultrasonics, etc.) and the reasons why some of these failed to provide the functionality that was offered by the vision approach ultimately adopted.There is nothing unique about the application of vision systems in the detection of surface defects. However, in this research program, a number of factors have considerably complicated the application. These include lighting problems and the difficulties encountered in acquiring images within a confined cylindrical space. This paper documents the techniques that have been used to resolve some of these practical image acquisition and processing problems and the relative merits of each approach. The paper also examines some of the algorithmic problems involved in detection of particular surface anomalies in components through a range of techniques and concludes that the one most suited to the surfaces in the pressure vessel case-study is the so-called “region-growing” approach.

A new FMS architecture based upon networked DSP servo technology

This paper presents a critical evaluation of existing FMS architectures and the academic and industrial design and development strategies used during their formulation. The paper seeks to address the need for, and value of, existing architectures within the industrial arena. More importantly however, this paper puts forward a new two-tier distributed control architecture for FMS based upon new (real-time) networkable DSP servo control methodologies developed by one of the authors for Softronics in Australia. The ramifications of these methodologies are substantial, not only in terms of FMS control, but in the overall simplification of such systems and the development of flexible fixturing devices over the coming decade. This paper also postulates on how new FMS architectures can be developed from such technologies and details why such architectures could be more appropriate to industry needs than those that are currently in existence.

A PID-type fuzzy controller model for machine control applications

This paper introduces a PID-like fuzzy controller model, which consists of only five fuzzy rules. Each fuzzy rule is designed to carry out a single control task. A self-learning procedure is used to determine the input scale factor for auto-tuning the system. A new performance criterion is suggested as an object function for the auto-tuning procedure. The features of this fuzzy controller, used in position control applications, are demonstrated by the simulation results of two different types of plants — a d.c. motor and an inverted pendulum.

A geometrical approach to computer-aided process planning for computer-controlled machine tools

This paper documents part of a research program which has been under way at the CIM Centre at Swinburne University of Technology since 1989. The purpose of the research program was to develop an open-architecture machine tool control system and then to see how that system could be used to change the distribution of traditional manufacturing design, planning and control functions. This paper examines one part of that research program and focuses on a methodology which could prove to be useful in the machine tool selection, cutter selection and cutter path generation phases of process planning for cutting operations on workpieces in computer-controlled machine tools.It is suggested that a configuration space transform be used for each cutter/machine tool combination to find the volume that the combination could remove from the uncut workpiece without removing any of the material that will form the final workpiece. A method of comparing these volumes from different combinations is then outlined. The output of this method is a “reasonable” sequence of machine tools and cutters. Path planning can then be carried out for each of the chosen combinations using a method similar to the one used to find the possible volume to be removed.Possible implementation techniques, and their limitations on existing computer hardware, are discussed and the most promising of these are identified, based upon some properties of configuration space transforms.

CHESS: A methodology for resolving scheduling and dispatch problems in FMSs

The objective of the research, presented herein, was to determine whether or not the makespan performance of an FMS could be improved by a methodology which draws parallels with the actions of a human chess player in resolving decision problems in an environment where optimal solutions were computationally intractable with current processing technologies. The methodology was given the acronym CHESS (Control Heuristic Embedded System Simulator) and provides a mechanism for using short-term simulation look-aheads to resolve contention problems. The research also sought to determine the relationship between performance improvement and “look-ahead distance.” The results of the research highlight the fact that the methodology could provide considerable reductions in the number of contentions and the makespan time for a given range of part types (approximately 20 percent for the test-case applications). The most pertinent results, however, are those that highlight the effectiveness of look-ahead distance in terms of improving system performance, and these may have a potential to provide a significant impact in a range of different areas.