Emulation of modular manufacturing machines using CAD modelling

Designing, testing and debugging a machine control system which controls mechatronic hardware elements can be a complex, time consuming and costly procedure. It is often extremely difficult for the system builder to envisage in advance the effects of small changes to the control system logic, with potentially dangerous results if the hardware consists of heavy machinery. It is also rare that a system builder will arrive at a working prototype on the first attempt and discovering the reasons for incorrect operation without a suitable means of comprehending the problems can be an arduous task. This paper describes an approach which supports the designing, testing and debugging of modular manufacturing machines using 3D graphical models of the machine hardware. The paper emphasises the underlying methodology of the approach, which involves collecting timing data from the executing control system under development, then emulating the operation of the machine by using this data to drive a graphical model of the hardware. The term “emulation” is used to mean modelling using data captured from the real machine as opposed to “simulation” which synthesises data. The work builds on previous research at the MSI Research Institute concerned with the control of modular machines. Two new extensions to this work are described here, which form the basis of the emulation capability. The first is the addition of the ability to execute the control system without the mechatronic hardware elements present whilst still retaining the operational behaviour of the application. The second is the mechanism for collecting the run-time data which defines these operational characteristics, to drive the machine emulation. The features of the custom 3D modeller are presented and its use for machine emulation is described. An example of a real control system under development is given to illustrate the complete process. The research objectives of the work described here are concerned with the fundamental problems designers encounter when trying to prototype the control systems of modular machines. The research has shown that the ability to execute the control system with or without the mechatronic hardware elements present can be a considerable advantage if supported by a CAD-based emulation system.