Import upstream snapshot 57d13ead53206a6bf0db3d66f86506ae8c2ce01a

Upstream: https://github.com/pollen-robotics/bam Upstream-Commit: 57d13ead53206a6bf0db3d66f86506ae8c2ce01a Upstream-Branch: mjlab_frictionloss
2026-08-28 15:42:08 +08:00
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+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