Getting Started

  1. Intro
  2. Using this Library in Python
  3. Kivy GUI

Intro

TBD

Using this Library in Python

After you have followed the Getting Started section in ODrive Docs and have successfully controlled your motor using odrivetool, it is time to start using the odrive_helpers library.

We can install this library using a pip install:

pip3 install dpea_odrive

Note that import errors in actual projects are likely caused by the old import file structure: e.g.

from odrive_helpers import *

Should actually be:

from dpea_odrive.odrive_helpers import *

Issues might also arise from having a newer version of the odrive library: ensure that you’re on v 0.5.4 by running:

pip3 install odrive==0.5.4

This library will allow you to automate the process of using odrivetool by bundling many of the commands into Python. For example, to move the motor one revolution in odrivetool we would need to do the following,

odrv0.axis0.requested_state = AXIS_STATE_FULL_CALIBRATION_SEQUENCE
odrv0.axis0.requested_state = AXIS_STATE_CLOSED_LOOP_CONTROL
odrv0.axis0.controller.config.control_mode = CONTROL_MODE_POSITION_CONTROL
odrv0.axis0.controller.input_pos = 1

But, using the odrive_helpers library we would simply need to run commands such as

axis0.calibrate()
axis0.set_pos(1)

To experiment with the odrive_helpers library, run ipython3 and follow along the various examples in the sidebar.

Kivy GUI

After you have tested each example, let us finish by making a Kivy GUI. You will find template files in the KivyTemplate folder of this repository. Your goal with this GUI is to have the following –

  • A button that toggles between moving the motor 5 rotations clockwise and counterclockwise
  • A slider that controls the velocity of the motor
  • A second slider that controls the acceleration of the motor (i.e. two sliders to handle ramped velocity)
    • Consider changing your velocity slider to use ramped velocity and retrieve the acceleration value from the second slider.
  • If using a constrained motor setup (ex. lead screw with endstops), then add a button that homes the motor. You can home the motor using an endstop sensor/switch or until a wall is hit. Refer to the homing example for more info.
  • Another screen that controls the motor with trapezoidal trajectory control. Have text boxes for acceleration, target position, and deceleration plus a submit button to send the command to the motor.
  • Another screen which utilizes a GPIO pin to move the motor when a sensor or switch is activated.