The Semiandrogynous Docking Interface combines gender-mate interfaces with the advantages of androgynous ports. In a few words, actuating one interface it changes into a “drogue” configuration, letting the other port penetrate it; then, it closes around to create a solid joint. The innovation of the proposed solution is related to its extreme simplicity, avoiding complex latches and mechanisms.


After the approach, one of the interfaces shifts its shape to the “open” configuration, in order to receive the other port, through the movement of the blue actuated disk. Then, the two mechanisms can move to contact and the movement of the actuated disk closes the left port petals around the right port ones, while the docking interfaces push each other, stiffening the joint with a pre-load.

This solution allows to conjugate the shape sifting and the locking actuations, using only one actuator for both the operations. It is also important to underline that in the docking configuration this interface creates a solid joint depending only by the actuator pushing force: the transmitted loads propagate only in the actuator direction, giving the possibility to use the linear cams instead of elastic components for the shape shifting mechanism.



The mechanism is  composed by a large number of different components. To realize the first prototype, 3D printing was choosen: with the  Sharebot™ 3D-printer the interfaces were quickly produced, to start as soon as possible the test campaign.



The docking interface is in testing in our facilities, evaluating the docking procedure performance.

The test-bed consist in:

  • a target interface, actuated with an off-the-shelf linear motor and mounted on a fixed support equipped with loads cells to measure forces transmitted by the actuation and the docking procedure;
  • a chaser, suspended with small strings on a frame free to move on a rail toward the target.;
  • a spring system, mounted behind the chaser and its frame, to give them the required approach velocity.


Tests allowed to determine the mechanism working range in terms of maximal allowable angular and lateral misalignments that can still lead to a nominal docking, as reported in figure for two different approach velocities. It is visible that the docking ports can manage up to 5 degrees  or 15 mm of misalignment (in green); for larger values, a non-nominal docking configuration may be still realizable (yellow areas).

Misalignments results
For further information on the Semiandrogynous Docking Interface please feel free to contact Dr. Lorenzo Olivieri with the form below, thank you!

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