8be13016bc
Upstream: https://github.com/pollen-robotics/bam Upstream-Commit: 57d13ead53206a6bf0db3d66f86506ae8c2ce01a Upstream-Branch: mjlab_frictionloss
67 lines
2.5 KiB
ReStructuredText
67 lines
2.5 KiB
ReStructuredText
Hardware Setup
|
|
==============
|
|
|
|
BAM's identification pipeline requires a pendulum test bench with variable
|
|
loads and lengths to increase the variety of the collected logs. The pendulum
|
|
is attached directly to the actuator's output shaft, optionally using a
|
|
counter-shaft when the actuator supports it.
|
|
|
|
To present the identification process, the Dynamixel XL-330 motor is used as
|
|
a case study. The instructions are similar for other actuators, adjusting only
|
|
for the mass and length parameters.
|
|
|
|
Requirements
|
|
------------
|
|
|
|
The hardware required for the identification process is as follows:
|
|
|
|
- **A set of rigid arms of varying lengths**.
|
|
|
|
The mass of the arms should be negligible compared to the attached loads.
|
|
Therefore, it is recommended to use 3D-printed or laser-cut wooden arms for
|
|
smaller motors handling light loads, and to reserve metal arms for more
|
|
powerful motors.
|
|
|
|
- **A set of weights compatible with the arms**.
|
|
|
|
The masses must be heavy enough to generate a wide range of load torques.
|
|
|
|
- **A mounting bracket for the actuator**.
|
|
|
|
The setup must ensure that the actuator remains firmly secured during data
|
|
logging, despite the fast movements of the weights at the end of the arm. The
|
|
arm-weight assemblies must have sufficient clearance to oscillate between
|
|
+/- 90° relative to the vertical position.
|
|
|
|
- **A communication interface for the actuator**.
|
|
|
|
Once the hardware is gathered, you must record the mass of the weights as well
|
|
as the length and mass of the arms. These parameters are mandatory for the identification process.
|
|
|
|
Example: Dynamixel XL-330
|
|
-------------------------
|
|
|
|
Here is an example of a test bench for the Dynamixel XL-330 actuator.
|
|
The pendulum arms are 3D printed; you can refer to the 3D model for inspiration
|
|
`here <https://cad.onshape.com/documents/c132b33797dc72aa58be8a7c/v/d9921c19039fee61b5e51bba/e/8e6b266057c61625732fd9b0?renderMode=0&uiState=6a447ab873e2fce629279db5>`_.
|
|
|
|
.. image:: /_static/hardware_1.png
|
|
:width: 80%
|
|
:align: center
|
|
:alt: 3D-printed pendulum test bench for the Dynamixel XL-330
|
|
|
|
The interface with the actuator is established using a U2D2 kit.
|
|
|
|
.. image:: /_static/hardware_2.png
|
|
:width: 80%
|
|
:align: center
|
|
:alt: U2D2 communication interface
|
|
|
|
The complete setup is shown below. The pendulum is attached to the
|
|
actuator's output shaft, and the masses are fixed to the end of the
|
|
pendulum arm.
|
|
|
|
.. image:: /_static/hardware_3.png
|
|
:width: 80%
|
|
:align: center
|
|
:alt: Complete Dynamixel XL-330 test bench setup |