3 Hidden PX4 SITL tricks for everyday development · 2019-06-26 · 3 Hidden PX4 SITL tricks for...

3 Hidden PX4 SITL tricks for everyday development

Julian Oes - 2019-06-20

3 Hidden PX4 SITL tricks for everyday development

What is Software In The Loop (SITL) simulation?

Simulator PX4

Sensor values

Actuator outputs

Local computer

3 Hidden PX4 SITL tricks for everyday development 4

https://makeameme.org/meme/the-simulation-environment

3 Hidden PX4 SITL tricks for everyday development

1 Lockstep

3 Hidden PX4 SITL tricks for everyday development

Common problems with SITL● CPU load too high

● Interruptions can cause crashes

3 Hidden PX4 SITL tricks for everyday development

How does lockstep work?Sensor valuesand timestamp

Actuator outputs

Simulator PX4

https://dev.px4.io/v1.9.0/en/simulation/#lockstep-simulation

3 Hidden PX4 SITL tricks for everyday development

How does lockstep initialize?

Sensor valuesand timestamp

Simulator PX4

Actuator outputs

3 Hidden PX4 SITL tricks for everyday development

Why should I use lockstep?

● Bonus: Run simulations faster or slower than realtime 💡

https://beorganizing.com/2017/12/22/dear-old-computer-ive-moved/

● Pause to inspect or debug ✅● Runs better on slower computers ✅

https://giphy.com/explore/hamster-wheel

3 Hidden PX4 SITL tricks for everyday development

How to pause?

Press P

3 Hidden PX4 SITL tricks for everyday development

How to speed up or slow down?

https://dev.px4.io/v1.9.0/en/simulation/#simulation_speed

3 Hidden PX4 SITL tricks for everyday development

Demo

3 Hidden PX4 SITL tricks for everyday development

2 Shell scripting

3 Hidden PX4 SITL tricks for everyday development

NuttShell on NuttX

nsh>

https://docs.px4.io/en/flight_controller/pixhawk.html

3 Hidden PX4 SITL tricks for everyday development

NuttShell

3 Hidden PX4 SITL tricks for everyday development

Startup

3 Hidden PX4 SITL tricks for everyday development

Startup

3 Hidden PX4 SITL tricks for everyday development

./px4 sh rcS ekf2 start px4-ekf2 startaliasevaluatecall

IPC call

ekf2 threadspawn

What about SITL?

https://dev.px4.io/v1.9.0/en/concept/system_startup.html#posix-linuxmacos

How to use it

3 Hidden PX4 SITL tricks for everyday development

Use your system shell with SITL

https://dev.px4.io/v1.9.0/en/concept/system_startup.html#posix-linuxmacos



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3 Hidden PX4 SITL tricks for everyday development

Demo

3 Hidden PX4 SITL tricks for everyday development

3 Hidden PX4 SITL tricks for everyday development

3 Hidden PX4 SITL tricks for everyday development

3 Hidden PX4 SITL tricks for everyday development

3 Debugging with GDB, valgrind, callgrind

3 Hidden PX4 SITL tricks for everyday development

Debugging using GDB (or LLDB) in console

3 Hidden PX4 SITL tricks for everyday development

Debugging using GDB (or LLDB) in VSCode

https://dev.px4.io/master/en/setup/vscode.html (work in progress)

3 Hidden PX4 SITL tricks for everyday development

Demo

3 Hidden PX4 SITL tricks for everyday development

3 Hidden PX4 SITL tricks for everyday development

Memory error detection using valgrind● Find reads from uninitialized memory● Find memory leaks● Etc.

https://dev.px4.io/v1.9.0/en/setup/building_px4.html#make_targetshttp://www.valgrind.org/

3 Hidden PX4 SITL tricks for everyday development

Memory error detection using valgrind

3 Hidden PX4 SITL tricks for everyday development

Profiling using callgrind● Function call graph● Function call counts● Time spent in functions● And much more

https://dev.px4.io/v1.9.0/en/setup/building_px4.html#make_targetshttp://valgrind.org/docs/manual/cl-manual.html

3 Hidden PX4 SITL tricks for everyday development

Profiling using callgrind

3 Hidden PX4 SITL tricks for everyday development

KCacheGrind visualization of callgrind data

https://kcachegrind.github.io/html/Home.html

3 Hidden PX4 SITL tricks for everyday development

EKF2

3 Hidden PX4 SITL tricks for everyday development

3 Hidden PX4 SITL tricks for everyday development

http://www.quickmeme.com/meme/3qjtpp