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--- ece4560:biped:03com [2017/10/10 14:27] – created typos
+++ ece4560:biped:03com [2024/08/20 21:38] (current) – external edit 127.0.0.1
@@ Line 8: / Line 8: @@
 <code>[ pos_com ] = com( obj, a_ref_frame )</code>
-This method will compute the center of mass (CoM) position of your biped robot with respect to the 'TORSO', 'LEFT_FOOT', or 'RIGHT_FOOT' reference/stance frame (specified by ''a_ref_frame''). The CoM position will additionally change based on the robot's current joint configuration. In order to accomplish this, you'll need to know the mass and CoM position of each individual link, with respect to the frame rigidly attached to that link. We'll assume the mass of the plastic frames, relative to the motors, is negligible; you can assume all mass comprising each link is concentrated at the center of each link's motor. Since the torso link doesn't consist of a motor, it will be massless for the time being. I suggest you create a function similar to ''set_geometry( ... )'' (as well as associated class properties) to set the mass and CoM position associated with each link; alternatively, you can just replace ''set_geometry( ... )'' with something more general.
+This method will compute the center of mass (CoM) position of your biped robot with respect to the **TORSO**, **LEFT_FOOT**, or **RIGHT_FOOT** reference/stance frame (specified by ''a_ref_frame''). The CoM position will additionally change based on the robot's current joint configuration. In order to accomplish this, you'll need to know the mass and CoM position of each individual link, with respect to the frame rigidly attached to that link. We'll assume the mass of the plastic frames, relative to the motors, is negligible; you can assume all mass comprising each link is concentrated at the center of each link's motor. Since the torso link doesn't consist of a motor, it will be massless for the time being. I suggest you create a function similar to ''set_geometry( ... )'' (as well as associated class properties) to set the mass and CoM position associated with each link; alternatively, you can just replace ''set_geometry( ... )'' with something more general.
 Mechanical drawings/specifications associated with the motors and frames being used on your bipeds can be found at:
-[[http://support.robotis.com/en/product/actuator/dynamixel/ax_series/dxl_ax_actuator.htm | AX-12A motor specifications]]
+[[https://emanual.robotis.com/docs/en/dxl/ax/ax-12a/ | AX-12A motor specifications]]
-[[http://www.robotis.com/view/AX-12A_18A/AX-12A.pdf | AX-12A motor drawing]]
+[[http://en.robotis.com/service/downloadpage.php?ca_id=70 | PDF Drawings: AX-12A motor, FP04-F4 plastic frame, FP04-F3 plastic frame and other FP04-* plastic frames]]
-[[http://www.robotis.com/view/FP04-F4/FP04-F4.pdf | FP04-F4 plastic frame drawing]]
-[[http://www.robotis.com/view/FP04-F3/FP04-F3.pdf | FP04-F3 plastic frame drawing]]
 **2.** Update ''plotTF( obj )'' to additionally plot a marker (eg. green, circled 'X') at the biped's center of mass location.
-Pick 3 different joint configurations for your biped. Display a new plot of the biped for each joint configuration, with CoM overlaid. Additionally, ensure the 3 plots cover all stance frames: 'TORSO', 'LEFT_FOOT' and 'RIGHT_FOOT' (ie. 3 plots total; each plot assumes a different stance/reference frame).
+Pick 3 different joint configurations for your biped. Display a new plot of the biped for each joint configuration, with CoM overlaid. Additionally, ensure the 3 plots cover all stance frames: **TORSO**, **LEFT_FOOT** and **RIGHT_FOOT** (ie. 3 plots total; each plot assumes a different stance/reference frame).
 **3.** Update ''animateTrajectory( obj, a_time, a_joint_traj )'' to also plot the CoM position of your biped over the course of the entire trajectory. As your biped joints and links move, you should see the CoM position of the biped move accordingly.