Attitude Management

\uD83E\uDD14 Problem Statement

In order to fly most drones, some form of closed loop control is required to manage the attitude of the aircraft. Attitude manager will, as the name suggests, manage the attitude of the aircraft for the given flight mode (behaviour based on pilot inputs) and frame type

🎯 Scope

Must have:	Control the aircraft such that aircraft response matches pilot inputs Accept pilot & machine inputs Be useful on multiple aircraft Ability to switch the behaviour of the aircraft
Nice to have:
Not in scope:	Calculate aircraft state in space Automous functionality requiring coordination over “long” periods of time

\uD83D\uDDD3 Timeline

See asana

\uD83D\uDEA9 Milestones and deadlines

Milestone	Deadline	Required Elements
FW2 - Manual Fixed Wing	21 Jul 2023	Attitude manager takes input controls and passes them through to motors
FW3 - Fixed Wing Fly by Wire A	04 Aug 2023	Control algorithm to target pitch/roll angles Data collection from sensorfusion Control algorithm configurations (e.g. PID gains) Configurable values for min/max pitch/roll angles
Q1 - Quad Acro	18 Aug 2023	Control algorithm to control rate of rotation on each axis + throttle Configurable frame type (e.g. quad vs fixed wing)
FW4 - Fixed Wing Fly by Wire B	18 Aug 2023	Rate of climb/decent maps pitch input Airspeed maps to throttle input Configurable max climb rate & max/min airspeed
Q2 - Quad Stabilize	01 Sep 2023	Control algorithm to map stick inputs to (pitch/roll) angles of the aircraft
FW5 - Fixed Wing Cruise	01 Sep 2023	Control algorithm to compensate for disturbances and maintain ground track
Q3 - Quad Altitude Hold	15 Sep 2023	Control algorithm combining stabilize mode with rate of climb/decent
FW6 - Fixed Wing Auto Takeoff	15 Sep 2023	Cruise mode + Path manager coordination Flight mode switching
Q4 - Quad Loiter	29 Sep 2023	Control algorithm to hold position with stick inputs mapping to speed

🔧 Requirements Breakdown

FW2

Take input controls
- Receive channel inputs, corresponding to yaw, pitch, roll
  - float percentage values
  - Receive from SM
Pass instructions to motor
- Send percentage value (speed, or angle) for each motor
  - AM call’s drivers directly
- Dshot Driver
- PWM driver

Task Brainstorming:

Talk to SM team (Gagan) about how we are getting RC inputs and its format

Actually implementing receiving the inputs (i.e. function parameters)

Nice to have (If we finish early): Make sure this is done in a thread-safe manner

Converting RC channel input from SM into motor output values

Map each input channel to the appropriate output values

Determine correct direction, which motors are relevant

Implement calls to the motor drivers using the converted values

Interface with motor drivers, make sure it works as expected (e.g. input format)

Talk to the people assigned to the drivers

Have configuration of which motor is which (servos vs bldcs) in the models folder

And what type of control they are (e.g. rudder, throttle)

Nice to have: Set up AM thread (as opposed to simple function call)

FW3

Control pitch and roll with a PID algorithm
- Implement PID controller (for each axis)
  - Calculate error between setpoint and current state
  - Implement loop to apply P, I, & D calculations
  - Each output value (roll, pitch) maps to motors in the same way as in previous milestone
- Configurable gains (PID terms)
  - Can be modified during runtime
- Configurable max roll & pitch angle
- Defining and running the controller at a specified frequency
Get pitch and roll from SF in a thread safe manner.
- Talk to people, make sure input format is as we expect
- Get this in the appropriate format to use for the PID current state
Convert roll and pitch input to desired state
- Should be constrained according to max angle configurations
Create a thread for AM
- Run the thread at a fixed frequency (e.g. 200Hz)
Update SM inputs to be thread safe
Consider publisher-subscriber model and implement if appropriate