Week 05/11 to 05/17

In this week, the position sensing system cannot be used in the Maker Faire event, so we are focusing on how to help other teams. In addition, we need to make sure the corrugated metal strip will not get off which may affect the bogie moving.
Moreover, we had a final presentation in this week, so we spent most of the time to prepare it.

Final Presentation (Position Sensing Team)

week 05/04 to 05/10

In this week, our team did the last test with app team. Unfortunately, the result was disappointed. The position sensing system is completed, we have the position sensor and the corrugated ferrous strips ready.

We first tested the sensor on the bogie with the completed program. The accuracy was 20% and it was low, but very precised.

We retested the system with some sensor commented out, especially the ultrasonic sensor, the accuracy increased to eighty percent. The Mobile App team and us confirmed that the run time of the program was too long for the position sensor to detect and count all the peaks as expected.
The mobile app team and the control team decided to reconnect some of the sensors to the interrupt pins, such as the hall effect sensors and the ultrasonic sensors,and wish to increased the loop time of the program. However, the accuracy of the position senors was even lower,  there is still something blocking the position sensing code.
The program could be solve by moving the position sensors to the interrupt pins too. However, because maker faire is approaching, the teams are trying to be conservative, and we have no idea what the will bring to the overall program if two of the sensers are on the interrupt pins.
Therefore, there would not be enough time for us to finished the programming and testing in this semester. 

Week 04/27 to 05/03

In this week, our team focused on fixing the corrugated metal strips, especially for the curve position. After we did the test for the sensor, we found that when the bogie passed the curve, some of the peaks of the strips would miss data. It means the sensor was not close enough to the strips. Therefore, we took off all the corner strips, and add a double tape between strips and track. It could reduce the distance between the sensor and the strips.
In addition, the sensor bracket was not as good as what we expected, so we designed another one. Also, we will test on Thursday or Friday.

Week 4/19 to 4/26

This week, the team was focusing on testing the position sensing system with the mobile app team. We tested our sensing. However, the sensor bracket was too far away from the corrugated metal strip at some place around the track, the team decided to design sensor brackets with different gaps between the sensor and the corrugated metal strips. The team will test the sensor brackets in this rest of this week.

Week 4/12 to 4/19

The team mainly focused on the presentation. On the other hand, we were informed by the Mobile app team before the Paseo that our sensor did not work properly with digital pins. Thus, we have to switch to analog pins and convert the analog signal into digital signal in our program. And the program has to be retested in next week.

Week 4/5 to 4/12

This week was the Paseo Public Prototyping Challenge. Even though the position sensing system was not ready in the Paseo event, the position sensing team still participated in the whole Paseo event. We help assemble, dissemble and transporting the model. We also introduce the Spartan Superway project to the publics on the event.

Week 3/29 to 4/5

This is the week before the Paseo Public Prototyping Challenge. The team was informed that the track was completed. The team started to attach the corrugated metal strip on the tack. The adhesive we use to attach corrugated strip on the track is super glue. The team had tried hot glue, Epoxy and High-Strength spray adhesive. None of these adhesives work with our design. Thus, the team decided to use super glue instead. The corrugated metal strips were attached on the track. There was another new problem found. The corrugated metal strips have to leave space for the screws for assemble and dissemble the track, there no quick solution for the problem right now.

The mobile application team informed us that the communication system between the podcars was not ready yet, thus, the position sensing system will not be ready for the Paseo event.

3/22 to 3/29

It was spring break, all team members were out of town during the break. However, the sensor bracket for the Hall Effect sensors and the magnets were redesigned before the break. The drawing was sent to the 3D printing shop, and the 3D print was in process. The sensor should be ready at the end of the break, and the team will start wiring up the encoder after the break.

Week 3/15 to 3/22

This week, the team spend time on manufacturing the corrugated metal strip for the whole track. The team first cut out metal strips with the sheet metal shear in the shop, then use our device to create the corrugated metal strips. Because of random error made by human during cutting out the metal strips, the width of the metal strip cannot be exactly 5 mm as designed. Our team tried to control the cutting process in order to keep the width of the metal strip to be 5.5 ± 0.5 mm. A few strips was measured to be out of the tolerance level because of the improper manufacture process, and we replaced them with new strips. The strips were successfully cut and corrugated, the team is waiting for the completion of the track.

03/09/2017-03/15/2017

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

03/02/2017-03/08/2017

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:

02/23/2017-03/01/2017

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.

2/15/2017 to 2/22/2017

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.

02/09/2017-02/16/2017

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.

02/01/2017-02/08/2017

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.

Week 12/01 to Week 12/07

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. 

Week 11/13 to 11/30

 The corrugated metal strip the team made was not fit for the track, thus the team sent out several quotes to nearly 10 companies that sell customizable metal parts. It was Thanksgiving Week, there were no shipping and other services until Monday of the next week. However, there was no reply from these companies.

The team designed a 3D model for one segment of the replacement of the corrugated metal strip. The design was shown in figure 1. The price for 3D printing the segment with stainless steel in order to cover the whole track was determined to be about $400. However, since there was no offering price from any companies for bending a corrugated metal strip with the team’s original design. The 3D printing price cannot be evaluated or compared.

Week 11/17 to 11/23

In this week, our team already finished the final designed of the sensor mount. And we will use 3D printer to make in the coming week. However, the corrugated metal strip we got from last week was not idea as what we thought. Firstly, its distance between peaks was not really accurate as we want. Secondly, the square wave shape was not good either. Therefore, we just contacted with a 3D printer show. And we think it will be more accurate.

Moreover, we found out another problem is which side the strip should set on the track. At the beginning, we wanted set it on the inner orbit. Nevertheless, we realized when the bogie get into the parking place, the outer orbit has to have the strip. In this case, the bogie should have both side sensor. Otherwise, we could not determine the position when the bogie get into the parking place. So we will try to solve this program during the coming week.

Week 11/9 to 11/16

This week, the team had talked to the software development team regarding to the algorithm of position sensing. After the discussion, the team decided to use the station ID as one of the reference for position sensor. However, after meeting with the software development team, the team also found we need to have reference for position sensing after track switching, and the issue will be discussed with the control team about the magnet and sensor they will be using.

The team gathered and came up with a design on the holder for the sensor with the new magnet. However, the CAD drawing was not able to be completed in this week after the team spending significant amount of time on designing a proper holder.

Since November is ending, the team will arrange more meetings at the end of the 3^rd week if November and the 4^th week because of the holidays. Hopefully, the sensor holder will be completely built.

The team like to test the sensors on a piece of corrugated sheet metal with fine corrugations. However, the corrugated sheet metal is not arriving and the website does not provide any tracking resources. The sheet metal will be cut in to strip and tested after its arrival.

Week 11/03 to Week 11/09

For this week, our team already got the new magnets, the size of magnet does very fit for our design. In addition, we successful manufacture the corrugated metal strip sample. However, we have some question about the Arduino code, so we are going to ask Dr. Furman in the coming week. 

In addition, we will determine the distance between the new magnet and sensor in order to design the proper sensor holder. Because the magnets arrived at 11/6/2016, the team have not had a chance to test it,so the design and the CAD drawing of the sensor is planned to be finished in this weekend. And a 3D printed model of the sensor holder will be available next week
On the other hand, after the sample of the corrugated metal strip was made, even though the strip was good for rapid prototype and testing, the 5mm distance between peaks was determined to be too large for accuracy. Thus, the team will consider making a smaller size corrugated metal strip in order for more accurate position sensing.