Fig. 2. Block diagram of the system for nanomachine mechanics.

HMM fragments (blue) deposited on the functionalised lateral surface of a pulled micropipette (cyan) are brought to interact with the actin filament (red) attached with the correct polarity ( + ) via gelsolin (yellow) to the bead trapped in the focus of the DLOT (pink). Force generation produces the movement of the bead away from the focus of the DLOT. The switch (AS) selects the feedback signal that, together with the command (black), feeds the summing amplifier Σ that drives the piezo nanopositioner: in position clamp (red) the feedback signal is the position of the nanopositioner x carrying the support for the myosin array; in force clamp (green) the feedback signal is the force (F, calculated as the product of the stiffness of the trap (e) times the change in position of the bead x_bead); in length clamp (blue) the feedback signal is the change in the distance L between the position of the bead and the myosin array support.