In this week, our team was focusing on programming the position sensing system. The idea was to create a function which counts for once when one of the sensors detects a signal change from HIGH to LOW, calculates the corresponding distance from the counts, and display the distance of the podcar from the last station. The program was finished, but the team is facing a problem of experiencing a high-frequency signal change of the sensors if the podcar stops at a position where the sensor detects a portion of the peak. The team is planning on adding a LOW PASS DIGITAL FILTER to our program. Hopefully, the problem can be solve with the low pass digital filter.However, we are trying to get advice from the app development team first.
Attached is the presentation 1 from our team:https://drive.google.com/open?id=0B2G9D1-TIftEQkZlRDJIRUliMWc
Wednesday, March 15, 2017
In this week, our team mainly focused on the presentation. In order to display the precision of our sensing system design, we made speed testing device. This device was made by a circular wood board, a corrugated metal strip, and a Hall Effect sensor. We fixed the strip on the edge of the wood board, and also we fixed the Hall Effect sensor on another wood board. The distance between sensor and the strip would be about 3mm. The outlook will be shown below(Figure 2).
In addition, we also did some improvement for the device which used for making the corrugated metal strip. The outlook will be shown below also(Figure 1).
Figure 1: Figure 2:
Wednesday, March 1, 2017
In this week, our team already found the acceptable sheet metal. The gage of the sheet metal is 30 which was what we expected. We decided to use this sheet metal for our corrugated metal strip. We cut a small piece from the sheet metal for testing. The result was promised. Therefore, we decided to use it for our project. Our next goal is cut the piece out from the sheet metal. The width of the piece will be 5mm.
In addition, we refined the gear set platform. We added a base for the platform in order to level it. We found the gears would be pushed apart when bending the metal strip. Thus, we add a piece of wood to connect the top of the two screws. The added wood piece would keep the gears together. The refined gear set works perfectly with our new sheet metal. Our team is ready for corrugated metal strip fabrication.
Wednesday, February 22, 2017
After failing several times with wood, the team decided to move on to the backup plan which is 3D printing out the gears. This week, the gears are printed out with ABS. The team assembled the gear together on the wood board, and test the gear set with a sample ironic strip, and the strip was successful corrugated. With the gears successfully made, the team will be able to make corrugated metal strips in large volume.
In this week, our team tried to use the wood board to create two set of gears which used for manufacturing the corrugated metal strip by hand. Unfortunately, we failed. At the beginning, we used a wood board which thickness is 1cm. After we cut out all the teeth of the wood gear, we realized the teeth are very brittle. When two gears rotated for making the strip, one of the teeth broke. Therefore, we decided to use a thicker wood board which is 2cm to do it again.
Manufacturing the thicker one is a lot harder than the old one. Especially, when we tried to make the teeth, we had met a lot of trouble. Firstly, we could not make the same distance between each tooth by hand. It will cause the unequal distance between the peaks of the corrugated metal strip. Secondly, at the tip of the teeth, we needed to sand it a little bit. It can make the rotation smooth. When we sanded it, we needed to be really careful. It is because the width of each teeth required minimum 3mm. Under that much limitation conditions, we realized we failed again. Fortunately, we had a backup plan which is 3D print. We asked help from our friend who has a 3D printer. Also, we start to draw it out by Solidworks. The gear set could be done by next week.
Wednesday, February 8, 2017
At the beginning of this semester, vehicle position sensing will focus on manufacturing the corrugated metal strip. Due to the limitation of the budget, we have to give up our original idea which was using 3D printer to make the strip. Instead of that, we will try to make it by our own.
In this week, in order to manufacturing the corrugated metal strip, we talked to the track manufacturing team. They do not have time to help us about it, but they gave us some useful suggestion. For example, we are going to make to gears for manufacturing the strip. They told us some their experience how to make a perfect gear.
So far, we already made two perfect cylinder. Also, we plan to finished the gear teeth and install them to a platform in the following week. The team is looking for steel sheet supplier which can provide us cheap and thin iron sheet. Because there will be no load acting on the corrugated metal strip, the properties of the metal does not matter as long as it can be easily corrugated. In the moment, we are looking for steel sheet with gage 28 or 30.
The program of the corrugated detection was finished. However, we still need to integrate our part with the vehicle control team because our programs share location information together.
Wednesday, December 7, 2016
For this week, the most time we spent on was preparing our final presentation and first draft report. In addition, our team is focusing on doing the final testing the position sensing system with a constant speed. Through the testing, we realized the speed that the sensor can sense is about 20cm/s. Since the vehicle control team have not determine the speed of the bogie yet, we cannot test the actual bogie speed in our system. Lastly, due to sensor mount is not perfect as what we expected, the sensing result is not very stable. Therefore, we did some adjustment the sensor mount.