AME 3623: Project 7: Proportional-Derivative Control and Tuning + Lateral Position Sensing

• All components of the project are due by Friday, April 12th at 11:59 pm
• 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:

• tune PD-control parameters so as to achieve near critically-damped behavior of the hovercraft, and
• compute lateral positiona and instantaneous velocity.

Component 1: Hardware

• Balance your craft so that when the chamber is pressurized, the craft lifts off the ground uniformly and does not drift laterally (much).

• Verify that that the cameras are still working before starting on this project.

Component 2: Software

Implement the following functionality:

• Continue to use the orientation LEDs to display the current orientation error.

• The LED bar should continue to reflect orientation rate.

• In pd_step(), sum together the proportional error (project 6) and derivative (project 5) terms in computing torque.

• In imu_step(), receiving characters '+' or '-' should increment / decrement your orientation goal in steps of 20 degrees. Remember that orientation goal should always stay between +/- 180 degrees.

• Continue to use your FSM from project 6.

Component 3: Tuning and Testing

• At the end of the previous project, you should have a reasonable choice of Kp. This should cause your craft to move definitively toward the orientation goal, though it will likely oscillate around the goal (perhaps damped, perhaps not).

• Slowly increase Kd until most of the oscillation has been removed.

• After tuning, the craft should be able to recover from disturbances from the orientation goal. In addition, as the orientation error approaches and then crosses 180 degree error, the thrust fans should flip polarity (e.g., shifting from hard right to hard left).

• Your hovercraft should behave properly given a range of starting orientations and goals.

• Remember that printf() is an expensive operation in terms of time. Although useful for debugging, it can cause serious problems when used inside of a control loop.

Component 4: Cameras

• Initialization of cameras in setup()

• camera_task / camera_step()

Update camera_step() and surrounding code as follows:

• Add global variable:

  float cartesian_velocity[3];
  

• Change your call to compute_chassis_motion() to be:

  compute_chassis_motion(adx, ady, cartesian_change);       
  

  where cartesian_change is a local array of floats

• After the call to compute_chassis_motion:
  • Add the changes to cartesian_position
  • Set cartesian_velocity to be cartesian_change / dt
  • Clear adx/ady

• Add to report step: print out on a single line cartesian_position and cartesian_velocity

• Add to imu step: if the character 'C' is typed, reset the lateral positions to zero

Note that cartesian_position is in the local coordinate frame of the hovercraft and not a global coordinate frame. For example, a move forward, followed by a turn by 90 degrees and then a second move forward will be sensed as a just a movement along the X direction and in rotation (plus some noise), but you should observe no movement along the y axis.

What to Hand In

• Demonstration/Code Review: All group members must be present. The demonstration must be completed by Tuesday, April 14th.

• Check in the following to your project 7 area of your subversion tree:
  • Documented code: See the project 1 specification for detailed documentation requirements.

• Personal report: Catme surveys must be completed by Tuesday, April 14th.

Grading

• Each person must accumulate at least three personal programming credits over the course of the semester. This project offers one.

• To receive credit, you must be the primary designer, implementer and debugger of the component. This does not mean that your other group members should not be looking over your shoulder. But: you must do the "driving."

• 35%: Project implementation
• 30%: Demonstration of working project (to either of the TA or the instructor)
• 35%: 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: Fri Apr 3 22:51:48 2020