System design of a three dimensional co-ordinate measuring machine

Orr, M.D.P., 1992. System design of a three dimensional co-ordinate measuring machine. MPhil, Nottingham Trent University.

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The aim of the project was to produce a new motor control system for the range of Three Dimensional Coordinate Measuring Machines (CMM) manufactured at W.A.Metrology, Forbes Close, Long Eaton. The design and implementation of this new generation of Measuring Machines which has created a product to- enter an expanding export trade especially in the European single market. The thesis explains about the Measuring Machine industry showing how and why components are measured on Co-ordinate Measuring Machines and indicating how the procurement of a CMM can be justified.

The thesis will show how the existing controller used at W.A.Metrology needed to be improved to enable the company to compete in this high technology industry. An embedded processor was chosen from bench mark tests made on different processors. It was shown from these tests that the Transputer was five times faster in executing the same code as its main competitors. The Transputer was shown to lend itself very easily to the design of the controller, using 16 bit transputers to control the readout, drive and handbox, and a 32 bit transputer with a co-processor to control the move algorithm and the mathematical calculations. The electronic configuration of the control system is explained, showing how the system interconnects and communicates using the Inmos links. The modular design of the electronics is shown indicating how each of the components of the system are independent of each other. The parallel processes on each of the transputers are indicated showing how the system interconnects in software.

The performance of the new controller is shown to accelerate and decelerate over ten times faster than the previous system. The loop time of the new controller has decreased from 64 milliseconds to a possible one millisecond allowing greater control over the movement of the Measuring Machine. The results of the move algorithm enables a move tunnel of less than 100 microns enabling the measuring probe to move very accurately round the work piece. The adaptive design of the controller is shown with the addition of the non-contact probing system which was added to the control system by using an Inmos link and simple protocol. The overall improved performance of the new controller has enable parts to be measured up to four times faster than the previous controller without changing the mechanical construction of the Measuring Machine.

Item Type: Thesis
Creators: Orr, M.D.P.
Date: 1992
ISBN: 9781369324082
Divisions: Schools > School of Science and Technology
Record created by: Linda Sullivan
Date Added: 10 Nov 2020 15:50
Last Modified: 05 Oct 2023 09:55

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