P14226: RC Camera Car
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Project Deliverables Summary

Table of Contents

Project Deliverables Summary

For the RC Camera Car senior design project, the following deliverables are being developed to accomplish the project objective. A brief summary of the current status of these components can be seen below. The project will be completed in May of 2014.

Problem Statement

P14226 Project Summary

RC Car Platform with Cameras and Sensors

Chassis Modifications

The car chassis used in the Freescale Cup was modified to accomplish the objectives of this project. This will provide the testing platform for the coding done in the second phase of the project. A video of the car following the modifications can be found here.

Chassis Documentation

Servo Mount Optical Switches and Encoders
Original Freescale Cup Chassis Modified Chassis Status 12-1-13

Wireless Communication and Data Capture

For the Controls application, wheel speeds from the differential drive system need to be captured. Custom hubs with integrated encoder discs were made that allow for direct connection to the Freescale Cup chassis. The optical switches used were available reflective QRB1134 phototransistors. The design went through two iterations, with the final product shown below. A video of the performance testing done can be found here.
Second Design Encoder and Optical Switches

XBee's are being used to transmit data to and from the car and the Freescale KL25Z boards. Preliminary testing was done with an Arduino to transmit encoder data back a computer which recorded the values in excel, which resulted in a range of approxiamtely 141 ft indoors. A video of wireless data transmission using the Xbee's with the KL25Z in real time using MBED can be found here.

Xbee Communication with KL25Z Arduino Encoder Transmission Setup

Encoder data was taken to test the setup. The car was set at a dead stop and accelerated at full speed before braking and reversing at full speed, coming back to a stop at the starting point. The data collected yielded good results that were as expected, but there were a number of outlier points caused by noise in the collection method. We believe this can be corrected using a derivative smoothing method.

Filtered Forward Data Filtered Reverse Data
Wheel Speed Data

From the above data, we were able to gather the following statistics about the vehicle movement. These compare very favorably with those outlined in our metrics.

Stats from Graph
Metric Spec Units
0 to max speed 2.8 s
max speed to 0 2.4 s
max speed 10 ft/s

Electrical Plans

A detailed electrical plan for the project can be seen below. This document summarizes and documents the approach that will be taken with modifying the TFC motor shield and making a perfboard shield for the Xbee and encoder circuits.

Electrical Plans

Wireless Video Transmission

After much discussion, it was decided that an analog output camera transmitted over analog RX/TX set was the best option for wireless video. Proof of concept was accomplished using a mini helmet camera and video TX/RX boards donated by the RIT ME Robotics Lab. A video of this can be seen here.

Using information gained in this testing, we were able to find a 5.8GHz RC first person view (FPV) camera kit from Ready Made RC LLC designed for RC planes. This kit includes a camera, transmitter, receiver, and all of the connecting cords necessary for the wireless video transmission system. These components are designed to be small for RC applicationa and will be connected to the car as seen below.

Car Component CAD Mockup

A power budget and weight analysis for the components can be seen below. This system will be fine for our application.

Final Power Budget

DDR Weight Analysis

Component Protection

The strategy for protection of the car components focuses mainly on the use of an effective bumper to dissipate collision energy. After some preliminary testing and two revisions, the bumper below was developed that exhibits many of the desired properties will still being modular enough to change with the final car design.
New Bumper Design

Driving Station with Controller

Console Chair

The console table was an area of this project which allowed for significant innovation on the part of the mechanical engineers, as few constraints were placed on the construction besides our budget. The setup only needs to seat the user and provide a mounting station for the electronics, but any modifications help improve the immersive experience and professional appearance. In this way, the table has seen many revisions, but the points of interest of its construction can be summarized below.

The CAD model and final product can be seen below.

Console CAD Model

Updated Console 12-11-13

Console Steering

A Logitech MOMO force feedback USB steering wheel and pedal assembly was donated to the project by Tim Southerton. Due to unreliable drivers, this device was modified to allow easy-access to the internal electronics by way of a hinge mechanism. A KL25Z was also mounted inside the enclosure, which is were we hope to mount all of the console electronics.
Console with Access Hatch KL25Z Board Mount

The internal electronics of the controller were analyzed and the signals necessary for our project were isolated using oscilloscopes and multimeters. These signals were then run to the KL25Z mounted in the enclosure for processing.

Steering Controller Electrical Data

Pedal Controller Electrical Data

Encoder Scope Data Optical Switch Scope Data

Dashboard

After some searching, the MC9S12HY64 dashboard instrument panel was identified as the perfect source of indicators for our project. This demonstration board is made to showcase Freescale hardware and provides all the lights, gauges, and buttons we can program to pair with our console. An acrylic cover and stand were fabricated to protect the board and mount the assembly to the console. A video of the final piece running the preloaded demo can be seen here.
MC9S12HY64 Demo Board Board with Mount and Guard

Course and Storage

The course to be used for the project will be the Freescale Cup tarp track provided by the computer engineering department. We are currently budget limited on the course, but as a boundary of the course we are looking at 100 ft of 3" perforated plastic drainage tubing. Depending on the constraints imposed by Imagine RIT, we are also considering simple plastic cones to bound the course. All of our components are stored in a locker and in bay 5 or 6 of the MSD area on the 4th floor of the RIT engineering building.
Tarp Dimensions Tarp in MSD Area

A timing gate was created for our project to provide a competitive element to the racing events and allow for measurement of the car performance to compare with the encoder data. This wil be used with the course to measure lap times.

Timing Gate POC

Timing Gate Electrical Data

Characterizing Parameters of the System

These parameters are to be established in MSD II.

Source Code for Low Level Processing

This code is to be developed during MSD II.

Interface for Student Coding

Console Computer

The general approach for the data flow at the console is complicated by the inclusion of a computer, which is needed for processing the Controls application with a simple user interface. A computer tower is being provided for free by Bill Finch in the RIT ME department to run MATLAB for the Controls processing of the project. The tower will be rigidly mounted to the console and password protected. A summary of the data flow on the console can be seen in the flowchart below.
Console Flowchart

Preliminary Differential Drive Model and Code

The differential drive model developed for this car can be seen below. Inputs to the model will come from the user throttle input and from encoders mounted on each rear drive wheel of the car. The model will output the motor speed data to be transmitted to the car.

Differential Drive Model

Supporting Documentation

Along with this site, a binder of documentation is to be developed for this project to allow for easy reproducibility.

Lab Topics

Lab topics will be developed through this project to provide a modules for use in a undergraduate computer engineering Controls class. The class is currently being taught by the project customer, Dr. Juan Cockburn.

Lab Topics

Bill of Material (BOM)

A budget was established for the project to keep track of money spent and donated components. This can be seen below.

Budget 12/6/13

Current Budget

MSD II Testing / To Do Short List

For a more detailed assessment, see MSD II Planning.

Risk Assessment

An updated risk assessment for the project regarding target subsystems which are currently being investigated can be seen below.

MSD 1 Risk Assessment PDF