7.1 Introduction
Students taking this module will work in pairs and complete two assignments and are required to submit an group report on each. Each page of the report must be labelled with the initials of the person primarily responsible for its contents.
Both assignments carry equal marks.
It is assumed that you are familiar with using Excel, if you are not then you should study a text such as ref. E1.
No prior knowledge of Matlab - Simulink is assumed, but you must read the Matlab - Simulink notes before attending the session at the University and plan how you will build your model.

7.2 Assignment 1.

Your group will be allocated a configuration to investigate. You will investigate the behaviour of the system in general and specifically the motion of the load when the motor is switched on. Initially assume that when the motor is turned on the motor provides a step input torque of 110 Nm.
You should model this system first by developing a suitable Excel spreadsheet and second by developing a Matlab Simulink model.
You must develop the Excel model first, and plan how you will do the Simulink model. The Simulink work will be done at Plymouth and you must have you model planned in advance, you will not have time to complete the Simulink work unless you have completed the Excel model and planned the Simulink model.

7.3 Assumptions
You may assume:

• the frame of the system is infinitely stiff.
• the inertia of the winding drum is 1.5 kgm²
• the mass and radii of gyration of the motor shaft and gear is: 1 kg, 20 mm and for the intermediate shaft and gear: 2kg, 40 mm
• the gear ratio is 3.5 for each stage
• the load is 3000 N
• the wire rope used is nominally 6 mm diameter, 6 x 19 standard hoisting grade with a E value of 83 GPa.
• the steel used for the wire rope 'plow steel' has a UTS of 640 MPa
• the mass of the wire rope may be ignored
• additional assumptions may be made e.g. assume the wire rope can transmit compression as well as tension

The marking scheme for this assignment will be:

Presentation	10%
Excel solution	30%
Simulink solution	30%
Discussion of results	30%

Link to notes on modelling a problem with an Excel Spread Sheet

Link to notes on modelling a problem with Matlab Simulink

This assignment is due in by 4pm on Tuesday 16th December 2003.

7.4 Assignment 2. - Distance learning students (assignment for the Plymouth based students will be published soon).
Choose a component or system where you have been involved in the design and / or manufacture. Describe the work that was done to ensure the reliability of this component or system and in the light of experience, critically appraise the performance and if appropriate, recommend how the reliability / performance could have been improved.

The marking scheme for this assignment will be:

Presentation	10%
Description of the product and system with supporting analysis	30%
Analysis of the reliability	30%
Possible improvements	30%

This assignment is due in by 4pm on Friday 2nd April 2004.

Return to module introduction

David J Grieve, 6th October 2003.