Difference between revisions of "S19: Run D.B.C"

Revision as of 22:14, 7 May 2019

ABSTRACT

The RUN-D.B.C project, involves the design and construction of an autonomously navigating RC car. Development of the R.C car's subsystem modules will be divided amongst and performed by seven team members. Each team member will lead or significantly contribute to the development of at least one subsystem.

INTRODUCTION & OBJECTIVES

SCHEDULE

BILL OF MATERIALS (GENERAL PARTS)

HARDWARE INTEGRATION PCB

Hardware Design

The hardware integration PCB was designed with two goals:

1. Minimize the footprint of the onboard electronics
2. Minimize the chances of wires disconnecting, during drives

To accomplish these goals, all controllers were directly connected to the board's 34 pin header arrays, while all sensors were connected to the board, using ribbon cables and locking connectors. The master controller's header pins were inverted and then connected to a header array on top of the PCB, while the other controllers were mounted to the bottom. This guaranteed secure power and signal transmission paths, throughout the system.

The board consisted of 4 layers:

Signal
3.3V
5.0V
GND

Technical Challenges

Design

• Balancing priorities between HW design and getting a working prototype
• Finalizing a PCB design, when some components and module designs are not nailed down

Assembly

• DB-9 connector for CAN dongle was wired backwards in the PCB design. Because there are several unused pins, we were able to just.
• Spacing for headers with clips were not accounted for properly in the design. two of them are very close. It's a tight fit, but it should work.
• Wireless antenna connector on master board not accounted for in footprint, it may have to be removed to avoid interference with one connector.

Bill Of Materials

WIRING HARNESS

Hardware Design

<Picture and information, including links to your PCB

Bill Of Materials

CAN NETWORK

<Talk about your message IDs or communication strategy, such as periodic transmission, MIA management etc.>

Hardware Design

<Show your CAN bus hardware design>

DBC File

<Gitlab link to your DBC file> <You can optionally use an inline image>

ANDROID MOBILE APPLICATION

<Picture and link to Gitlab>

Hardware Design

Software Design

<List the code modules that are being called periodically.>

Technical Challenges

<Bullet or Headings of a module>

Bug Tracking

<Problem Summary> <Problem Resolution>

Bill Of Materials

BRIDGE CONTROLLER

<Picture and link to Gitlab>

Hardware Design

Software Design

<List the code modules that are being called periodically.>

Technical Challenges

<Problem Summary> <Problem Resolution>

Bill Of Materials

GEOGRAPHIC CONTROLLER

Hardware Design

Software Design

<List the code modules that are being called periodically.>

Technical Challenges

<Bullet or Headings of a module>

Bug Tracking

<Problem Summary> <Problem Resolution>

Bill Of Materials

MASTER CONTROLLER

<Picture and link to Gitlab>

Hardware Design

The master controller is primarily interfaced with the other controllers over CAN bus. The other main interface is control of the LCD display for debug data, which communicates over UART.

Software Design

<List the code modules that are being called periodically.>

• LCD display
• CAN read and send
• Navigation
  • obstacle avoidance
  • steer to checkpoint

Technical Challenges

<Bullet or Headings of a module>

Bug Tracking

<Problem Summary> <Problem Resolution>

Bill Of Materials

MOTOR CONTROLLER

<Picture and link to Gitlab>

Hardware Design

Software Design

<List the code modules that are being called periodically.>

Technical Challenges

<Bullet or Headings of a module>

• We had to change the PWM driver to hard code the sys_clock frequency. We found solution.

• Original encoder sourced is was designed to be a knob, not a motor encoder. The additional rotational resistance caused vibrations and resulted in it becoming disconnected from the motor shaft several times. The solution was to us a slightly more expensive encoder, designed for higher speed continuous operation on a motor.

Bug Tracking

<Problem Summary> <Problem Resolution>

Bill Of Materials

SENSOR CONTROLLER

<Picture and link to Gitlab>

Hardware Design

We put in a lot of thoughts on how sensors should be placed on the car. In order to facilitate easy adjustment of sensor direction, we incorporated circular grooves in the sensor bases so the mount left/right direction can be adjusted on the fly. The hinge of the sensor mount also allows sensors to be tiled up and down, together with the sensor mount, offering two degrees of freedom.

CAD Design

Picture on the left shows the hinge of the sensor guard can be adjusted to minimize the amount of interference between sensors. Picture on the right shows the hinge of the sensor mount allows sensors to be tiled up and down.

Placement for the Ultrasonic Sensors