#robotics Logs

Jun 30 2015

15:43 veverak so silent
15:50 deshipu yawn
15:58 deshipu so, I have this code for inverse kinematics of my robots
15:58 deshipu pretty simple stuff, some acos, some atan2
15:58 deshipu works perfectly on AVR-based microcontrollers
15:59 deshipu but I recently tried to compile it for Teensy 3.1, using the arduino IDE they provide
15:59 deshipu and the results are all completely off
16:25 Loshki If I were being paid, I'd run the known good version and dump critical variables. Then I'd run the 'bad' version and see where the values start to diverge...
16:37 deshipu yeah, I'm going to have to isolate individual parts and run them all separately
16:37 deshipu I was just hoping that there is sone obvious difference that I'm missing
16:46 wolfmanjm your IK code runs fine for me on non AVR, but note I converted everything to float, and use cosf, sinf atan2f etc everywhere as Arm stuff defaults to double not float as it does in AVR
16:46 wolfmanjm deshipu: it is a totally different compiler that teensy uses, so not surprising there are differences
16:48 wolfmanjm deshipu: https://gist.github.com/wolfmanjm/358fcb1564b36e63e60b
16:49 wolfmanjm I suspect the abs() is the problem, on arm abs() is integer only, so if you pass a float it will be truncated. I use std::abs() as you can see as that has a float version.
16:53 wolfmanjm FYI the Teensy does NOT have an FPU despite being an Arm M4... that surprised me a bit
17:08 deshipu hmmm
17:08 deshipu thabks!
17:08 deshipu thanks
17:08 deshipu I will try that tomorrow
18:14 JEntrep did you guys see the DARPA competition?
18:14 JEntrep I mean any YT videos of it
18:14 JEntrep ?
18:14 JEntrep a lot of fails
23:24 rue_house :)
23:33 rue_shop3 armyofevilrobots, step 1) (?) how to grind up big peices of plastic
23:34 rue_shop3 or turning 3mm filament into 1.75?