Hi Austin,
about the motor friction identification, you might be interested in this thread: Actuation Frictions Information - #2 by majid_khadiv
About the control scheme we use: We use PD control to put the robot in a desired position. We observe stick-slip behavior for small angles but overall for larger angles that we move, using this control scheme with a stiff P (P=5 Nm/rad, D=0.05 Nm s/rad at the output joint) works for us.
For dynamic motions we use a impedance control scheme, were we compute the desired torques at the joint based on the force we want to apply at the end of the endeffector. For this, we compute the jacobian J of the endeffector and then compute the torques via J^T * F. You can find more about this control scheme in the paper here: [1910.00093] An Open Torque-Controlled Modular Robot Architecture for Legged Locomotion Research
Best,
Julian