Multi Axis Motion Control System (NetVend)

Student: Kieran Hannagan

Supervisor: Richard Cocks

Category: Engineering Thesis Project - Computer Systems

In modern society, we live in a world where the constantly increasing level of technology has the ability to change the way in which we carry out everyday tasks. We can see this happening where people can already carry out their daily tasks and chores via the Internet with a few clicks of a mouse and a tap on the keyboard. This new world at your fingertips leaves individuals to put their valuable time towards more useful and worthwhile endeavours. The Internet has become a major tool not just for computer aficionados but for the average person to use what are now referred to as Internet-Enabled Systems. These so called Internet-Enabled Systems don’t just give the user an advantage, but also give a large benefit to the companies or individuals providing the service.

This thesis project is part of the NetVend project, which utilises the principal of Internet-Enabled Systems to produce a vending machine capable of distributing small electronic components within the department of Information Technology and Electrical Engineering at the University of Queensland. The goal of Netvend is to provide a modular, scalable, low cost, low maintenance internet vending machine with centralised administration and in-system upgradeable components. This particular project deals with the small component vending machine being developed for the University of Queensland laboratories. This thesis aims to implement a Multi-Axis Motion Control System for the displacement of the Small Component Vending Machine gantry and electromagnetic module. This includes the design and implementation of a hardware control board and the writing of software to reside on the board. This thesis carries on the control work by Tony Curtis and will attempt to implement the further suggestions recommended in his thesis in 2001. The implmentation to date can be seen below.

The hardware is to be centred around a Xilinx Spartan II Field Programmable Gate Array. This chip is a 200,000 gate FPGA with 142 possible Input/Output and will be used to drive the motors on the NetVend machine via two stepper motor indexers. The FPGA will also interface with a PROM used for configuration of the FPGA and several other essential components. Other interfaces include a keypad, LCD port, two RS232 ports (one for communication with the server and one for debugging purposes), two Dallas 1-Wire ports (one for communication with the E-mag module and one to interface to a Dallas 1-Wire keypad) and the port to the stepper motors. The board also has an on board 4 x 7 segment display for debug purposes. The Control board will be supplied by a 5 volt 2 amp power supply and will require defined voltage levels of 3.3 volts and 2.5 volts to cater for the different power supply characteristics of the components residing on the board. To accommodate this, two voltage regulators have been included, with a 5 volts down to 3.3 volts step-down linear regulator with a 1 amp supply capability, and a 3.3 volts down to 2.5 volts step-down linear regulator with an 800 milliamp capability. While these capabilities are significantly less than the maximum possible supply, the current requirements for these voltage levels fall significantly below that of the maximum current required by the components. The 3D version of the board can be seen below

The software involves the writing of code for the Xilinx Spartan II FPGA. This will be written using the Celoxica DK1 Design suite, which uses the Handle C compiler. This is unlike most FPGA systems, which use the VHDL language. The Celoxica Design suite was chosen for its ability to significantly shorten the design cycle by using a common language. With the Handle C compiler, little to no knowledge of in-depth digital system design is required to produce a working system in relatively little time. The software requires four main modules with a great deal of interaction between each. The significant areas being the design and implementation of the two RS232 ports, the code to control the stepper motors, the interfacing of the keypad and 7 segment display and the code for the Dallas 1-Wire ports.

Thesis Document (PDF)