Lesson test: The control loop, PID and stabilization

1.[1p]
In a feedback control loop, the error that the controller acts on is

the setpoint minus the measured value

Correct

the setpoint plus the measured value

The answer is: the setpoint minus the measured value

the motor command minus the throttle

The answer is: the setpoint minus the measured value

the battery voltage minus its nominal

The answer is: the setpoint minus the measured value

2.[2p]
The integral term of a PID controller exists mainly to

remove a steady offset that the proportional term leaves uncorrected

Correct

react fastest to sudden error

The answer is: remove a steady offset that the proportional term leaves uncorrected

amplify sensor noise

The answer is: remove a steady offset that the proportional term leaves uncorrected

set the loop rate

The answer is: remove a steady offset that the proportional term leaves uncorrected

3.[2p]
Too high a proportional gain tends to make a quadcopter

overshoot and oscillate

Correct

drift slowly off level

The answer is: overshoot and oscillate

ignore the pilot's stick

The answer is: overshoot and oscillate

run its battery flat faster

The answer is: overshoot and oscillate

4.[2p]
The derivative term improves stability by

easing off the correction as the error falls, damping the approach to target

Correct

summing the past error

The answer is: easing off the correction as the error falls, damping the approach to target

increasing the throttle

The answer is: easing off the correction as the error falls, damping the approach to target

measuring the yaw heading

The answer is: easing off the correction as the error falls, damping the approach to target

5.[2p]
A high derivative gain is dangerous because

the derivative of a noisy signal is noisier still, turning vibration into motor twitch and heat

Correct

it removes the steady offset too slowly

The answer is: the derivative of a noisy signal is noisier still, turning vibration into motor twitch and heat

it saturates the battery

The answer is: the derivative of a noisy signal is noisier still, turning vibration into motor twitch and heat

it inverts the craft

The answer is: the derivative of a noisy signal is noisier still, turning vibration into motor twitch and heat

6.[2p]
A rate controller has $K_{P} = 0.5$ . At an instant the roll rate error is 40 degrees per second. What is the proportional part of the correction, in command units?

CorrectNot quite: 20

7.[3p]
Self-levelling flight uses a cascade of two loops in which

an outer angle loop produces a rate setpoint that the inner rate loop then holds

Correct

two rate loops run in parallel and are averaged

The answer is: an outer angle loop produces a rate setpoint that the inner rate loop then holds

the angle loop replaces the mixer

The answer is: an outer angle loop produces a rate setpoint that the inner rate loop then holds

the rate loop commands the battery

The answer is: an outer angle loop produces a rate setpoint that the inner rate loop then holds

1.[1p] In a feedback control loop, the error that the controller acts on is

2.[2p] The integral term of a PID controller exists mainly to

3.[2p] Too high a proportional gain tends to make a quadcopter

4.[2p] The derivative term improves stability by

5.[2p] A high derivative gain is dangerous because

6.[2p] A rate controller has KP=0.5. At an instant the roll rate error is 40 degrees per second. What is the proportional part of the correction, in command units?

7.[3p] Self-levelling flight uses a cascade of two loops in which

1.[1p]
In a feedback control loop, the error that the controller acts on is

2.[2p]
The integral term of a PID controller exists mainly to

3.[2p]
Too high a proportional gain tends to make a quadcopter

4.[2p]
The derivative term improves stability by

5.[2p]
A high derivative gain is dangerous because

6.[2p]
A rate controller has $K_{P} = 0.5$ . At an instant the roll rate error is 40 degrees per second. What is the proportional part of the correction, in command units?

7.[3p]
Self-levelling flight uses a cascade of two loops in which