University of New Hampshire: FSAE ECE Progress Report Team Members: Christopher P. Loo & Joshua L. Moran Faculty Advisor: Francis C. Hludik, Jr., M.S. Courses Involved: ECE 541, ECE 543, ECE 562, ECE 633, ECE 634, ECE 617, ECE 618, ECE649 and ECE 714. Date: December 9 th 2009 Project Completion: May 12 th 2010 http://www.unh.edu/fsae/ 1
General Problem Definition: The Formula SAE is a competition designed for ambitious college students from all majors urging them to design, build, and compete with a single seat, open cockpit formula race car. It is an annual competition sponsored and promoted by the Society of Automotive Engineers (SAE). The event is available to students from all over the globe. There are limitations on engine and frame to challenge the creativity, comprehension, and aptitude of students competing in this event. Teams of students work together over the period of a school year to build a working formula-style race car. The racing car gets submitted alongside approximately 120 other vehicles from different universities and colleges to be judged and compared in multiple disciplines. The competition is designed to challenge the weekend road warrior/ auto crosser eager to take on another challenge. Novice weekend autocross drivers know that their car has to perform well in many regards. Good examples of those are braking, accelerating, and steering aspects. The race car ought to be inexpensive, effortless to maintain, and should allow a weekend participant to fit this activity into their schedule while not taking away from that individual s opportunity cost. Ergonomics, cost, aesthetics, reliability, and manufacturability of easy to operate interchangeable parts should aid in improving the vehicles marketability. The mission of this project is to conceive, design, and fabricate a formula-style, open wheeled/open cockpit, autocross racing car. The formula is to be presented as a one of a kind, original model for assessment as a production item and to be judged and evaluated against other competing designs. The car is to be evaluated in static and dynamic events. The static events include technical inspection, cost, presentation, and engineering design. The dynamic events are based on solo achievement trials and high performance track endurance. The end result should be a meaningful experience for young engineers in a challenging engineering project in addition to being part of a team environment working towards a common goal. There are two sub teams on the University of New Hampshire (UNH) FSAE Team. The first group, which will design and implement the general design of the car, is comprised of all mechanical engineers (MEs). The second group is comprised of all Electrical and Computer Engineers (ECEs). The main purpose of the ECE students is to understand all of the rules set forth by the FSAE rules committee, and use these rules to design and implement the electrical systems which will make up the car and ensure its performance. After our general objectives are completed we will then work on our specific design objectives. Specific Design Objectives: Our specific design objective involves taking two separate design projects and combining them into a single electrical system which will meet all of the FSAE requirements on electrical http://www.unh.edu/fsae/ 2
systems and assist the team in the competition. The first system which we are going to implement is a data acquisition system that will work in conjunction with the cars electronic control unit (ECU) to give the driver and the ground crew an up-to-date indication of the car's instantaneous and average performance. The electrical design team from last year designed a system to perform such a task and we hope to expand on their ideas and improve upon them by making the system smaller, lighter, and mobile. The previous years team did not have a way in which the driver could get a real time view of the data being acquired while on the course, we are hoping to improve upon this with the second system which we are hoping to integrate with the data acquisition system. To accomplish this, we will take that data that would normally be input into an on board computer and instead send it to a pocket PC or PDA that will be built into the steering wheel. This will allow the driver to see all of the information needed to make driving decisions based on real, up to date data, while also providing a computing platform from which we can implement the data acquisition system. This system will also take all of the data that is acquired and wirelessly transmit it to a computer located with the ground crew allowing the ground crew to have access to the information as well. The constants that will be associated with such a system are the number of inputs that will be available on the Pocket PC and how these will correspond with the number of sensors that must be utilized to acquire the information which is pertinent to the driver and the ground crew. The car will include three switches that will cut the electrical power to the car in case of emergency in accordance with the FSAE rules. The car will also include a relay box that will house the relays for every electrical system in the car. This box should have a quick connect and disconnect plug so that an old box can be swapped for a new or spare box without having to troubleshoot each individual relay. This should allow any relay problem to be resolved in a very short period of time. The wiring of the car will be mapped on a wiring diagram to reduce redundant wiring, ensure neatness, and thoroughness. Proper gauged wire will be needed to ensure that each wire can handle the power requirements unique to its application. Robust connectors will be used to insure the reliability of the interconnections. The system s wiring will be color coded to aid in troubleshooting, when needed. Implementation and Testing Plan: The implementation process for the car will be broken down into sub groups based on importance and how crucial it is to the cars operation. The first and foremost objective will be to make a wiring schematic for the car as the car will be unusable if it is not properly wired, thus when the car is ready to be wired we as a team will be prepared to do so. Our next task which is equally as crucial will be to calculate the amperage running through each wire so that we can obtain the proper gauge wire to ensure that it can safely and effectively run under the present conditions. For our specific design project, we will begin by researching and finding a wireless capable pocket PC that will be used as a combination data acquisition system and steering wheel display. There are many things that must be considered when we look for a pocket PC such as the actual computing components such as memory, battery life, and input/output connections. However we must also take into consideration other characteristics such as size since it is necessary it is small enough to fit inside the steering wheel yet also provides a screen that is both http://www.unh.edu/fsae/ 3
large enough that it can be seen by the driver during competition and capable of being seen in the conditions under which the driver will be competing, such as sunlight. We will then need to find and implement an interface between the ECU and pocket PC such that the PC can accept all of the information that is being sent to it and properly display it to the driver while simultaneously transmitting this through antenna through a wireless network back to the ground crew. In years past the FSAE team has implemented this wireless network using an omni-directional antenna, however during the longer races, such as the endurance competition, they discovered that the signal was too weak and the ground crew lost contact with the car. We plan on solving this problem by using a directional antenna located at the base station which will allow us to have the increased range necessary to stay in contact with the car without having to increase the amount of power that we use. When everything above is completed, we will then have approximately a month to test and troubleshoot all problems that we encounter. Project Progression: As a whole the UNH FSAE team began the year with a combination of design and fundraising. As with any design project one of the initial concerns for completion of the project is the acquisition of the funds necessary to complete the project. With the recent down turn in the economy the FSAE team has found that some of our sponsors from the past have had to scale back their charitable giving, leaving our team short of our planned goal. To compensate for this fact we have been focusing extra time on fundraising with fundraisers such as our calendar sale, ski pass raffle, and banquet ticket sales. Due to this fact we have delayed the purchase of many of the wiring components for the car until such a time as the car will be wired. However, the first thing that we did this semester to prepare for our design project was to review the wiring schematics for the VEMS ECU from last years team. The first step in wiring the ECU is to connect the supply voltage and ground to the proper pins: http://www.unh.edu/fsae/ 4
Once the ECU is supplied we will continue by connecting the primary trigger via the crank sensor. We must give this portion of the wiring special consideration, as the VR sensing equipment is very susceptible to electrical noise meaning that we must ensure that we use shielded cable (Coax) with the shielding grounded. The next component to wire into the ECU is the two temperature sensors that the VEMS system utilizes, the Inlet Air Temperature (IAT), and the Coolant Temperature (CT). The IAT is used in speed/density systems to calculate the amount of fuel required, while the CT is used to meter the required amount of warm-up fuel enrichment. The throttle position sensor is used by VEMS to provide fuel requirements in Alpha-N configuration and acceleration enrichment. http://www.unh.edu/fsae/ 5
Finally we will connect the Wideband Oxygen System (WBO2) to the ECU to ensure that the car is operating at the maximum power efficiency using proper fuel to air ratios. One of the private donations that we received at the beginning of the semester was the use of a pocket personal computer for testing purposes. We were planning on using this to test the software that was going to function as a data acquisition system and communicate with the VEMS electrical control unit before spending part of our limited budget on an expensive piece of equipment. Unfortunately, the VEMS is only compatible with Windows Mobile 5 or newer and the pocket personal computer we were given runs Windows Mobile 2003. We are currently in the process of exploring new options for implementing our design. We have chosen a model of pocket personal computer which we are planning to purchase and are just waiting on the funds necessary to make the purchase. With a newer operating system we believe that there should not be a problem interfacing the two devices. To allow the connection of the VEMS unit to our PC a serial port plug must be connected in the following way: http://www.unh.edu/fsae/ 6
This output serial port is a RS232 connection, which will then be connected to the Pocket PC via an Recommended Standard 232 (RS232) to Universal Serial Bus (USB) converter. The Pocket PC will then receive sensor data from the ECU and display the critical information in real time to the driver and ground crew. An example of the user interface is as follows: Unlike in years past where only the ground crew had access to data, it is our goal this year to allow real time sensory data to be viewed and analyzed by both the driver and the ground crew. To accomplish this we have the PC mounted in the cockpit of the car such that the driver is capable of viewing the screen at all times. We had originally intended for the PC to be mount inside of the steering wheel, however, after meeting with Controls subgroup and discussing various designs we have decided to move the mounting points to the dash board to allow for a http://www.unh.edu/fsae/ 7
more flexible steering wheel design as well as insuring that the driver is capable of viewing the screen undistorted even on tight turns. For the remainder of our responsibilities as the electrical members of the FSAE team we are dependent upon the completion of other aspects of the car. Such as the a framework onto which we can wire the cars electrical equipment in such a way as to comply with the FSAE guidelines and regulations. http://www.unh.edu/fsae/ 8