Engineering Experience 4: Design a Small Solar Vehicle/Nl/2013: Team AM4

Introduction
Umicore Solar Team is a project of Group T engaged in the development of a solar car. Every two year a group of master students create a car to drive a solar race in Australia. In their quest for additional budget, they want Apollo to create a small solar vehicle they can sell.

As Apollo we hope to succeed in creating the best solution for a cheap and easy to use SSV and after several weeks of hard work we are happy to present you our SSV:



Some features of our solution are:
 * A simple yet effective design: Our car is all about simplicity without consequences.
 * Speed: With features like a aerodynamic base plate and lightweight parts our car has the possibility to reach great speeds.
 * Durability: This comes in both our design and our choice of materials. We chose Plexi instead wood for a better durability.

Later on you will be able to follow our progress throughout the project this page we will show our progress on this project.

Our Team
Our team consists of 6 engineering students:

Week 1
During a short introduction of the project and meeting with our coach Hu Yunhao, we had been told there was already a deadline this week, so there was no time to lose! This first deadline was on Friday and we had to have several documents ready, such as the plan of approach, work breakdown structure and Gantt chart. After a short team meeting we split up the work and finished the required documents fairly quickly. There was only one task to complete: Our "company name" and logo. After consigning several ideas to the waste-paper basket, we were left with two names: Espeon and Apollo. Espeon is a sun Pokemon from the popular Japanese TV cartoon series and Apollo who was the Roman god of light and the sun. After some some debating we decided to go with Apollo.

Next week we have several tasks ahead of us, we will have our first seminar about the solar panel and the DC-motor, we will also start thinking about the design and concepts of our SSV.

http://commons.wikimedia.org/wiki/File:Apollo_Report_1.pdf

Week 2
Like we said in last week's blog we got our first seminar about the solar panel, but we also had an introduction to the Umicore Solar Team, explaining some concepts about what they do and what they stand for. After the seminars we had to fine tune our Gantt Chart to make the estimated hours more correct. The goal this week though, was to find the characteristics of our solar panel, this was done by measuring Voltage and Current with a variable resistor, with these results we could derive the diode factor of our solar cells and make a graph showing these characteristics.

Next week another seminar about the race strategy will follow and we will design our SSV

http://commons.wikimedia.org/wiki/File:Apollo_Report_2.pdf

Week 3
After a short seminar about the race strategy and gear ratio, it became clear we had some calculations to do on this subject. The gear ratio is one of the most crucial parts in the design of our SSV. We decided to first design the general structure of the car and to decide some important dimensions like the wheel size since these were also necessary for the calculations. After these decisions we started to unravel the methods to calculate the optimal gear ratio, this had to be done by hand and with Matlab, this took some time but become clear after some puzzling.

Next week we hope to have completed these calculations. Also new software will be brought up to simulate our SSV with Simulink.

http://commons.wikimedia.org/wiki/File:Report_3.pdf

Week 4
You know you like doing something when making the SSV is the highlight of your week. First off we had a seminar about using Simulink (thank god it was half an hour later, 8 o'clock classes are killing us). They thought us how to use it and simulate our solar panel and motor. With everything set up we could test the different resistors and more important, the gear ratio! Work is divided so that 3 persons are busy with the Simulink file, 2 are making the very cruel numerical calculations and the last one is writing the Case1 document. Spirits are high and we want to be the first to cross that finish line!

http://commons.wikimedia.org/wiki/File:Report_4.pdf

Week 5
With our feet wet from the 10cm high snow we start another week. The files of Matlab and simulink are a pain in the ass, but nevertheless they must be done. The SSV case1 document is getting longer as the characteristics of the solar panel and the gear ratio are added. It is hard to figure out how to do the Sankey diagram, and the simulink isn't doing what it's supposed to do. spirits are descending but we have to get through this part so the building can finally begin !

http://commons.wikimedia.org/wiki/File:Report_5.pdf

Week 6
This week the first case of the SSV must be finished. The designing is done but the calculations and Simulink file still give some trouble. We started noticing some errors in the calculations and forgot some things to do for this case. It will be a relief if this chapter is closed so we can begin building and testing.

http://commons.wikimedia.org/wiki/File:Report_6.pdf

Week 7
Today we thought about out the construction of the SSV and decided, after visiting several stores in Leuven,to order several components online, we hope to be able to construct a base for our SSV during Easterbreak so we are able to start advanced constructing the week after. There are still several things to think about though, such as the mounting of the motor.

Week 8
It's the week after Easter break. In the past 2 weeks we made a base plate for the SSV. it turned out to be quite big though, the weight is too high (over 1kg). We also examined the delivered material that we ordered online. Bad luck, the bearings were too big for the axles although they would have to fit perfectly. We have to think about how we are going to fix that. We also made some purchases for some mounting mechanisms and went back to FabLab for some additional materials. We also put everything together. Today we also had our first test about Case I.

This is the result:



Week 9
This week we were able to test our SSV on the real course. the first descend was beautiful, we rolled all the way back while the other groeps couldn't make it of the hill. But when we tested some more we saw some problems coming up. The car was not running in a straight line, this could have several reasons but after looking at the rear wheel we saw some imperfections which could be fixed by making a new piece made of thicker plexiglass. We also decided to make our car smaller so it was less likely to collide with the sides. This was done immediately in FabLab and it looks a lot better. We also started to work on SSV case II.

http://commons.wikimedia.org/wiki/File:Report_7.pdf

Here is the result:



Week 10
This week is all about Case II since we have finished our car by testing it on the circuit Friday last week. Several things have to be done to this report though. So we better get started!

http://commons.wikimedia.org/wiki/File:Report_8.pdf

Week 11
The deadline for case II is this week, due too holidays the printed version has to be handed in on Monday, but the digital version still has to be ready this Friday. We are working on the documents like the Gantt chart, the process report en the second case. At 11.30 our vehicles will be judged by the GroepT staff (secretly hoping for the most beautiful design.. In my opinion we are worthy of that price!). If the sun is shining we are going outside to test our vehicle with the solar panel attached.

Final Design
A photo of our final design can be found in the blog of week 9. There are a few choices we made that make our design different from the other vehicles. First off, we chose 3 wheels with the 2 wheels in the front. This gives the least friction with the ground while still keeping stability. The front axle is driven by the motor, so our vehicle drives in a straight line. To make sure the wheels drive smoothly we attached the front axle to the frame with bearings. In the back not the axle but the wheel is attached to a bearing, so we only had to buy 3 bearings in stead of 4. The material we chose is plexiglass. This is for 3 reasons: it is available at FabLab, it is a more durable en stronger material than wood, and it looks pretty awesome. The design of our frame is dedicated to aerodynamics, the drop-shaped single-layered plate gives nearly no drag. We kept it too the basics with our simple but effective design.