AME 3623: Project 3

All components of the project are due by Thursday, March 3rd at 8:55 am
Groups are the same as for project 1.
Discussion within groups is fine.
Discussion across groups may not be about the specifics of the solution (general programming/circuit issues are fine to discuss).

At the end of this project, you should be able to:

through low-level functions, control the speed and direction of DC motors through an H-bridge circuit, and
use a high-level program to test the functionality of the DC motor control interface.

Component 1: Microcontroller Circuit

The current amplifier board is composed of two full H-Bridge circuits. We will be using one full H-Bridge to control the lift fan (allowing us to control rotation speed and direction). We will split the other H-Bridge into two "Half Bridges": one for each of the left and right fans. This will allow us to control speed of these two fans, but not direction.

The detailed documentation for the motor control board can be found on the Pololu Web site.

The diagrams for the power wiring harness and the amplifier board are shown below. When adding the power amplifier board to your breadboard, place it on the edge as far away as possible from the microcontroller board. In subsequent projects, you will be adding multiple components to the breadboard, so keep the rest of the breadboard as clear as possible.

Add wires to connect the motor control board to the fans and to the batteries (6 screw terminal connectors on the right side of the board picture below):

Connect GND and VIN directly to the power harness (not to your 5V power supply provided by the Arduino board!!!). Make sure you do this without the batteries plugged in.
Connect the lift fan to port 2 (OUT 2A and 2B)
Connect the right fan: red wire to OUT 1A and black wire to power harness GND
Connect the left fan: red wire to OUT 1B and black wire to power harness GND

Connect the current amplifier board to your Atmel chip (the 15 pin connector on the left side of the board in the picture below):

Connect 1PWM (via a 10K-ohm pull-up resistor) and +5V(IN) to your Atmel's +5V power supply
Connect GND and GND to your Atmel's ground
Choose one of: timer1, 3, 4 or 5. For the chosen timer, you must have all three PWM pins available (they are labeled OCXA, OCXB and OCXC on the Arduino circuit diagram, where X = 1, 3, 4 or 5).
Connect the following to your Atmel to free digital output pins (but do NOT use B0 ... B3):
- 1INA ("input1"): Pulse-Width Modulated (PWM) input for the right fan. Connect to OCXA
- 1INB ("input2"): PWM input for the left fan. Connect to OCXB
- 2PWM ("input3"): PWM input for the lift fan. Connect to OCXC
- 2INB/2INA ("input4" and "input5": connect to two free digital output pins. These are used for direction control for the lift fan (0/1: one direction; 1/0: the other direction; 0/0 or 1/1: dynamic braking).

Power Wiring Harness

Power Amplifier Board

Component 2

Create the function interface that will generate the PWM signals for each of the three PWM inputs to the motor control board.

Define a new variable type in a new file called "project.h"

typedef enum {
   STOP,
   HOVER
} MotorDirection;

MotorDirection is the new variable type. STOP and HOVER are the two values that MotorDirection variables can take on. Remember to include "project.h" in your C file.

Implement the following functions:

void set_lift_motor_direction(MotorDirection direction) that sets the direction bits for the lift fan.
If direction == HOVER, then the lift fan should push air into the chamber, causing the craft to hover (assuming an appropriate level of thrust).
If direction == STOP, then the lift fan should pull air out of the chamber, causing the craft to be pulled to the ground.
void set_lift_motor_magnitude(int16_t magnitude) that sets the thrust magnitude for the lift fan. This function must ensure that magnitude falls within the range of 0... 1023 (which correspond to 0% ... 100% duty cycle). If the value does not fit within the range, then it should be clipped to this range. Remember that you have already implemented a useful function in the prior project.
void set_lateral_motor_magnitudes(int16_t magnitude_left, int16_t magnitude_right) that sets the thrust magnitude for the left and right fans. This function must ensure that magnitude_left and magnitude_right fall within the range of 0... 1023 (which correspond to 0% ... 100% duty cycle). If either does not, then the offending value should be clipped to this range.

Note:

Initialization of the three PWM channels must happen within your main() function (see the lecture notes on timers).

Component 3

Implement the following in your main() function:

Within your main while(1) loop:

If your switch is pressed:
- Set middle fan thrust direction to HOVER
- Slowly ramp the lift fan thrust upwards until 25% duty cycle
- Wait until the switch is released
- Slowly ramp the lift fan thrust downwards until zero
- Set thrust direction to STOP
- Slowly ramp the lift fan thrust upwards until 25% duty cycle
- Wait until the switch is pressed again
- Slowly ramp the lift fan thrust downwards until 0% duty cycle
Note: use your LEDs to indicate which phase of the program that you are in.
If your switch is not pressed:
- Slowly ramp the left fan up to a duty cycle of 25%
- Slowly Ramp the left fan down to 0%
- Slowly ramp the right fan up to a duty cycle of 25%
- Slowly ramp the right fan down to 0% duty cycle
Note: use your LEDs to indicate which phase of the program that you are in.

What to Hand In

Code: Check your documented code into your group subversion tree for project 3. This is due by Thursday, March 3rd at 8:55 am.
Demonstration/Code Review: All group members must be present. This must be completed by Friday, March 4th.
Personal report: fill out the CATME survey. This will be due shortly after the deadline. These personal reports are used to provide feedback to you and your group members. Individual grades will not be assigned if the survey is not filled out.

Grading

Personal programming credit: this project offers one programming credit.
Group grade distribution:
- 35%: Project implementation
- 30%: Demonstration of working project (to either of the TA or the instructor)
- 35%: Code documentation
Group Grading Rubric
Grades for individuals will be based on the group grade, but weighted by the assessed contributions of the group members to the non-personal programming items.

andrewhfagg -- gmail.com

Last modified: Wed Mar 2 23:34:58 2016