# Part 2: Tuning#

Write brief answers to all exercises in answers_pid.md.

## Problem 1: Ziegler-Nichols Method#

Imagine you are flying your drone and observing its flight for tuning it. Ideally, you would tune the $$K_p$$ by slowly increasing its value between flights until you can see the drone moving up and down with uniform oscillations. The final $$K_p$$ value that causes uniform oscillations is termed as $$K_u$$, the ultimate gain. While, the time difference between these two peaks during oscillations is termed as $$T_u$$, the ultimate period.

Exercises

1. Given $$K_u$$ = 500, $$T_u$$ = 10. Use your $$K_u$$ and $$T_u$$ values to compute $$K_p$$, $$K_i$$, and $$K_d$$ using Ziegler-Nichols Method.

## Problem 2: Flying with Velocity Control#

In velocity control, we use planar velocity measure from the camera as the process variable. The keyboard keys are used to set the setpoints.

Exercises

1. Now suppose you are flying in velocity mode over a blank white poster board. How do you expect the drone to behave, and why will it behave this way? hint: Think about why we fly over a highly textured planar surface.