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.

Week 10/26 to week 11/02

The powerpoint for presentation 2 is available at:

https://drive.google.com/open?id=0B2G9D1-TIftEc2ZQVHhtRThjbVE 

This week, the team was focusing on designing the sensor mount for our hall effect sensor. However, since the magnets we used for testing was too long, the team need to find a smaller magnet. On the other hand, we cannot decide the distance between the sensor and the magnet unless we test the magnets. Originally, the team decided to order magnets from Honeywell.

The magnet is 9.53 mm in length and much smaller than the original one with 25.3 mm length. However, the team found some much smaller magnets on ebay. Those magnets are cylindrical with 1/8 inch in length and 1/8 inch in diameter. And they are 50 times cheaper than the Honeywell magnets. Thus, the team decided to order the magnets from ebay, and they are arriving around 11/5. After, the team receiving and testing the magnets, the team will modify the current design of the sensor mounts. And the task will be done before the end of this week.

Week 10/20 to 10/26

In this week, we determined to use the digital Hall Effect sensor to do test for scanning the corrugated metal strip. The test was very successful. In this case, we did not have to worry about the corrugated metal strip design. It is because if we try to use the analog output Hall Effect sensor to scan the corrugated metal strip and magnet, then the distance between two peak (up and up), the peak to peak distance(up and down) and the deflection on each curve has to be very accurate. It will be a very big challenge to make this strip. For now, we use digital Hall Effect sensor, the strip only need to focus on the accurate of the distance between two peak (up and up). The design will be shown below.

Week10/12 - 10/19

According to the bogie team and the track development team, the distance between the inner and the outer tacks is 2 in (50.8 mm). The width of the part of the bogie in between the two tracks is 33.5 mm. Thus the distance between the bogie and the track is about 0.5*(50.8-33.5) = 8.65 mm. The height of the magnetic switches on the bogie is 7.5mm from datasheet, and it will scratch the track while turning. Thus, the height of the peak for the corrugated metal strip is design as 5 mm. See Figure 1.

Figure 1 Space between Tracks

The ground came up with three kinds of corrugated metal strip we might be using. They are square wave, sinusoid wave and trapezoid wave corrugated metal strips (See figure 2). Square wave will be our first choice because the sudden change of height will allow the Hall Effect senor to have clear digital output. The distance between peaks (d) is depended on the speed of the podcar and the resolution of the data acquisition device, which is the Arduino board in the SuperWay project. The team have to find out the maximum speed of the podcar in order to find the minimum distance between peaks.

Figure 2 Designs for Shapes of Corrugated Metal Strip

Moreover, the team had decided to put the Hall Effect sensor on a ski which extent out of the bogie in order to keep proper distance between the corrugated metal strip and the sensor. The team is also looking for a magnet with proper size and magnetic strength.

week 10/05 to 10/11

In this this week, we tried to determine the size of the ferrous strip. According to the control team and the bogie team, the magnets detector on the bogie will be kept. Keeping the magnet detector will allow us to stay with digital ouput sensor. However, the magnet detectors are occupying too much sapce on the bogie, which became a problem for us to install the metal strip on the track. We came up with a proposing solution for this, that is to cut out the upper part of the magnet detector, and we will attach the corrugated metal strip just right above the position of the magnet detector. The upper part of the magnet dector is for placing the screws, but currently the detector are mounted using glue. Thus, the screw holes are no longer needed.

The team also examinize the track, and found that the distance between the two side of the tracks are different every where, it is a big problem for us to decide the size of the corrugated metal strip in this case.

We already found a nice size hall effect sensor. The rest thing depended on how small of the strip we can make.

Week 9/29 to 10/04

This week, it is because we have to prepare for our presentation, so we do not have that much time spend on our project.
Overall, our team tried to ask some workshop in San Francisco to make the ferrous strip this week. Unfortunately, none of them can make for us. It is because the ferrous strip we expect is the distance between peak to peak and the distance between upward peak and downward peak have to be very accuracy. Probably, we have to ask help from some more workshops or companies in the coming week.
Moreover, we will test the new hall sensor in the coming week.

We also found some of the small bussiness websites which might be able to manufacture the corrugated metal strip we want, and we will contact them for more information.

http://www.builders-in-scale.com/bis/parts-metal.html
https://www.mechanicalmetals.com/accessory-items/foam-closure-strips-and-plugs/

Week 9/21 to 9/28

This week, our team met up with the vehicle control team to discuss about the feasibility of the Hall Effect sensors on both positioning and switching. Both team came up with the idea of using the Hall Effect sensor’s digital output as the positioning tool and using a second sensor for switching and detecting the magnets on the track. Originally we would like to keep the design of the Korean team. However, this idea was rejected by the Track development and Bogie team because the magnetic detector on the podcar will contact with the track. And the hold system needs to be redesigned if the control team wants to keep the magnetic detector. We tested the RFID sensor, but fail to make it work properly. Our team started searching some of the smaller Hall Effect sensors. And we are getting an A3144 Hall Effect sensor in recent days.

The team is also working on searching possible corrugated metal strip supplier on the market. We are looking for products similar to the metal strip that we want, and trying to contact the manufacturer of the product to search for possible assistance.

Vehicle Position Sensing Team Week 9/14/2016 – 9/21/2016

The week, the team was focus on testing the Hall Effect sensor, the test was done on Arduino base test environment. The circuit was constructed as shown: 

The Arduino was programmed using the following simple code:

#define hall 0

void setup() {

  pinMode(hall,INPUT);

  Serial.begin(9600);

}

void loop() {

  sensorValue = analogRead(analogInPin);

  Serial.print(sensorValue);

  delay(2);

}

Conclusion for Testing:

• The Sensor only can only detect ferrous object inside a 3mm range.
• The sensor we used for testing only outputs digital signal, which means its reading might not be effected by the magnets on the track.
•  The team tested the sensor with a magnets, the result confirmed that the sensor is not affected by magnets.

Recent plans

• The team need to find new corrugated ferrous strips with much narrower spacing between peaks.
• The team is looking for a new type of Hall Effect sensor which is able to provide analog output.

Vehicle Position Sensing Team Week 9/7/2016 – 9/14/2016

This week, our team has talked to Dr. Furman about the feasibility of using Hall or GMR sensors and corrugated ferrous strip to build the position sensing system. Dr. Furman has introduced the Hall Effect sensors and his idea about accurate position sensing system for the 1/12 scale model. After the discussion with Dr. Furman, our team listed out some difficulties and key parts of our plan.

1. The team has to test if the sensors are able to detect the ferrous strip and give correct feedbacks as we expected. And the test will be done using a large scale ferrous strip and sensor.
2. If the idea work, the team should figure out the size of the ferrous strips in order to achieve a high resolution sensor feedback.
3. There is limiting space between the vehicle and the track, the team have to figure out a way to attach the ferrous strip and the sensors on the track and the car.
4. The team must find the manufacturers which are able to provide us assistance on manufacturing high quality ferrous strips, otherwise we have to make it ourselves.

In conclusion, Dr. Furman provided plenty of useful information for our team, and the team has start working on the testing of sensors.

Configuration of Hall Effect Sensor and Ferrous Strip

Testing Circuit

Team Blog Assignment #1

• Members:
• Name: Qihuan (Kevin) Miao
• Skills: Matlab, Arduino coding, CAD drawing, C++
• Contact: Cell: 415-4268953 Email: miaokevin@hotmail.com
• Responsibilities: Coding, sensor testing, researching

• Name: Zhiwei Li (Alex)
• Skill: Arduino coding, Solid Work, CAD drawing
• Contact: Cell: 415-216-6084 Email: zli52@mail.ccsf.edu
• Responsibilities: Mechanical Part, Researching, sensor testing

• The Position sensing team is supposed to work with other vehicle control teams to develop a “smart” and autonomous multiple-podcar system. The main focus of the team is to solve the positioning problem in order to create an accurate and reliable podcar positioning system for the twelfth scale model this year. The team is supposed to work out position sensing system with linear magnetic encoders systems. The linear magnetic encoder system will be created by implement hall effect sensors and neodymium magnets with a corrugated piece of sheet metal on the guide way.

• Major task in recent weeks:

• Budget Estimate: Between $100 - $300

Zhiwei Li's schedule

Vehicle Position Sensing Team Scheduling

Vehicle Position Sensing Team Scheduling

Qihuan Miao's Schedule

Here is my classes schedule, I am available for anything without a class.