How is the base link defined?

[SugarWam]

Thank you for the great work! But i am really confused about the definition of the base link. suppose this is a robot with only one link:
rbtdef = sympybotics.RobotDef('Example Robot', [('pi/2', 0, 0, 'q')], dh_convention='standard') rbtdef.frictionmodel = {'Coulomb', 'viscous'} rbtdef.gravityacc = sympy.Matrix([0, 0,-9.81]) rbt = sympybotics.RobotDynCode(rbtdef, verbose=True) tau_str = sympybotics.robotcodegen.robot_code_to_func('C', rbt.g_code, 'tau_out', 'tau', rbtdef) print(tau_str)
i got tau_out[0] = 0. But as alpha is pi/2 and the gravity direction is along z-axis for the base link, the gravity term should not be 0 but something related to m and ly. is there anything wrong with my code? Thank you very much for help!

[cdsousa]

alpha = pi/2 rotates the frame of the end-effector, not the base. The axis of the joint is still parallel to the Z / gravity.
Check here: https://tools.glowbuzzer.com/kinviz