Derivation of the original Mechaduino code from jcchurch13.
Firmware
Changes:
- added an enable pin (pin 2, only 3.3 V compatible)
- Menu entry for generating a step response
- Menu entry for generating a dirac delta function
- deleted all modes other than position
- changed all float to integer operations
- added some filtering to the effort and D-Term
- Changed the frequency of the PID loop to 5 kHz
- Encoder readings are placed in its own ISR that runs with 10 kHz (oversampling)
- maximal step frequency = 40 kHz
- changed the PWM resolution from 8 bit to 9 bit
- PID auto tuning
- The lookup table is now in its own file (lookup_table.cpp)
- The Parameters are now in Configuration.cpp
- Added Language file for easy translation
- added an invert direction setting
- simple error register to save if an error occurred
- LED shows errors by different blinking patterns
- downhill simplex algorithm to fine tune the pid settings
LED blink pattern:
If an error occures the led will switch from constant on to different patterns. These patterns are separated from each other by a longer pause. After this pause one pattern will be shown and then after the pause the next pattern will be shown.
| Pattern | Error |
|---|---|
| Fast blinking | Timing error. This can occur if the mechaduino receives too much steps. Consider lowering your microsteps or limit the maximal speed |
| Long on | maximal error was reached |
| Long on, one flash | the maximal current was reached |
| Long on, two flashs | the lookup table shows some errors |
List of commands
To get an list of the possible commands send help over the serial monitor
| Command | Description | Arguments |
|---|---|---|
| help | prints this menu | |
| calibrate | starts the calibration routine | |
| diagnose | read Encoder Diagnostics | |
| state | shows and sets the motor state | -on, -off |
| stream | streams servo parameters | -f {int}, -on, -off |
| parameter | Get or set parameter | -set {-parameter} {value}, -get |
| error | get or reset the error register | -reset |
| dirac | generates a Delta-Distribution | -f {int} |
| response | generates a step response | -f {int}, -s {int} |
| error | get or reset the error register | -reset |
| autotune | PID auto tune | -c {byte}, -d |
| downhill | Downhhill simplex algorithm | -f {int}, -v {int}, -o |
| testmove | Starts a testmove for the servo | -f {int}, -v {int}, -o |
| interrupt | Starts or stops the ISR | -TC5 {bool}, -TC4 {bool} |
Examples
| Command | Description |
|---|---|
| parameter -set -Kp 1.095 | Sets the proportional gain of the servo to 1.095 |
| testmove -f 2500 -v 60 | Starts a test move with the velocity of 60 mm/s and a sampling rate of 2500 Hz |
| testmove -v 60 -o | Starts a test move with the velocity of 60 mm/s and the default sampling rate of 5000 Hz. Outputs the sampled points to the serial monitor |
Windows GUI
- Live view/stream motor parameter (angle, error, effort, ...)
- generate and analyze different test moves with different sampling rates (step response, dirac delta function, ...)
- change parameters without the need of serial commands
- generate a configuration file
- Log streamed motor parameter as txt or csv file
License
All Mechaduino related materials are released under the Creative Commons Attribution Share-Alike 4.0 License https://creativecommons.org/licenses/by-sa/4.0/
Much of the work is based on Mechaduino project: https://github.com/jcchurch13/Mechaduino-Firmware
Support
If you want to support me for further improvements and things like that, you can send me a small kickback with PayPal
