Thanks for all the replies!
Let me try to summarize and see if this is the right way of thinking.
Right now, I derived the complete dynamic equations for tau1, tau2 and tau3 in the case of a planar manipulator with actuators at the joints. Of course, tau1 is larger than tau2, which is larger...
This still holds true even though it is the same cable?
If I understand it correctly, it would then mean that the tension is highest between the motor and the first joint, creating a joint torque tau1 which is able to withstand all counteracting torques of the finger. The tension becomes lower...
@waross. Thankyou for your reply!
I still do not entirely get it, though. The way I see it is that tau1 is larger than tau2, which is larger than tau3. This seems logical, since the first joint also feels the inertia, combined spring forces and a larger moment due to external forces.
However...
I am working on creating a robotic finger with the design choice as in the picture above. The green cable should be attached to a motor/pulley, which is the driving actuator. The cable is then wound around three passive joint pulleys in the finger and each joint has a counteracting spring for...