Presented By:
Tim K. Sams

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TOUCH SCREEN USER INTERFACE FOR THE CORNELL AUTOMOTIVE X-PRIZE COMPETITION CAR
Abstract:
The project is to develop, in LabVIEW, the user interface and communication system for the touch screen dashboard to be used in the Cornell Automotive X-Prize competition car. In order to complete this project, I am developing a detailed and exhaustive list of parameters and
operating modes to be implemented, installing and ensuring my system compatibility to develop the software, and checking the interface compatibility with the current hardware in place in the vehicle. In the end, the touch screen will be able to report any and all needed data on a real time basis to the driver and passenger of the Cornell AXP car. They will be able to change the operating mode of the vehicle and monitor the current status of all the available metrics to ensure efficient operation of the vehicle. This is a critical component to the success of the Cornell
Automotive X-Prize team when it comes to race time, because fuel efficiency is paramount, and not being able to monitor the real time status of the vehicle could have a devastating impact on the vehicles operation in the competition.
Executive Summary
As a member of the Cornell Automotive X-Prize competition team, I was tasked with the creation of a user-friendly touch panel interface for use as the cars dashboard. For this competition it is imperative that the car operate as efficiently as possible, and the touch panel feedback serves as the eco-feedback to the driver and passenger of the car. Simple parameters that any normal car might have must also be portrayed on this system as well as the data that makes operation as a hybrid possible. It is also necessary to provide quick access to many of the details to facilitate quick debugging if something in the car goes wrong. As a means of testing, there was a preliminary test-bed car built that used the exact
same hardware used here. While some of the programming methods were retained, much of the software was written from scratch to facilitate faster data update rates. The hardware is all National Instruments LabVIEW based programming for the touch panel and FPGA. The FPGA
runs the car's systems whereas the touch panel serves more as a monitor. This eliminates the need for the driver and passenger to keep a laptop in the car to check the status. The software, completely written using LabVIEW, revolves around two main components. The first is the loop on the FPGA that serves as the cars onboard computer which
updates all of the necessary data variables and calculates needed values. The second is the loop and display setup on the touch panel which decodes the sent variables and transfers them into a viewable format on the front panel of the screen. In the final tests of the system, everything performed as desired. We were able to achieve a screen refresh rate of 20 Hz or every 50 ms. This is crucial to the operation of the car because it is the replacement to the cars original speedometer. When used at the shakedown stage of the competition there were no hardware or software issues other than the fact that glare seemed to be somewhat of an issue on the screen itself. One of the largest benefits of this system is the fact that it is very simple to modify on the fly and during the competition,
team members were able to quickly update the way the speed was displayed in order to avoid the glare issue. 5
Design Requirements
The objective of this project was to create a user-friendly and simple to operate user interface for use with the Cornell Automotive X-Prize (AXP) team competition car. The hardware interface to be used was a touch screen interface, implemented on a National Instruments embedded touch panel device. Initially, the program was meant to run on a small 5.6” touch panel device, but through considerable testing and implementations, we found that a much larger device with more processing power was necessary and the requirements changed in the second semester. This made it possible to utilize a 12” diagonal version of the touch panel embedded computer which enabled several new features in the design space as the new touch panel ran the embedded version of Windows XP. The following is a summary of the preliminary goals for this design project:
• Ability to provide real-time vehicle data such as: speed, battery level, miles per gallon, distance traveled, fuel level, and other driving habits as requested.
• Ability to switch between different operating modes, as specified by the AXP Team.
• Smooth, consistent, and simple operation. Should not require extensive practice or experience to operate.
• Extremely reliable, should operate under the normal circumstances experienced within a commercial vehicle.
• Must interface will all existing hardware within the vehicle, if the hardware is not already provided, will research and implement new hardware for our needs.
• The physical unit will conform to the interior design of the vehicle.
It is important to note that throughout the year several of the requirements and environment were changed, allowing for more efficient use of resources, such as:
• Transition from a 6’’ form factor screen to a 12’’ form factor.
• Removal of Driving mode feature – vehicle did not have different operating modes at the time of implementation6
Previous Work
One of the unique aspects of this project is that it was not the first time the AXP team