Sept 2023 - Feb 2024
As a part of my senior mechanical engineering capstone project, I designed a subsystem which allowed cube-shaped robotic modules to interconnect in any orientation while being able to sustain high static loading conditions.
When several modules are connected, the structure the models compose should be strong. The worst-case loading condition is when the modules are loaded with a 56 Nm bending moment in the canti-lever beam position.
There are two possible canti-lever beam loading positions: one where the connector is loaded with a bending moment and the other where the connector is loaded in torsional shear.
The mechanism consists of four active latches and four static latches. A single linear actuator is used to push and pull on a hub. Several linkages are driven by the hub which cause the active latches to lock into the static latches of an opposing connector.
The diagram only shows a single active latch for clarity.
To activate the mechanism, the linear actuator retracts, which spins the hub counter-clockwise.
The rotating hub pulls on the rod ends, which in turn pull on the top of the active latch, causing it to pivot.
The pivoting motion of the active latch causes the bottom half of the latch to swing out. When the connector is close enough to an opposing connector face, these extended latches hook into a mating connector's static latches.
This connection scheme needed to be as versatile as possible in order to allow the modules to connect in as many configurations as possible. There are a few key design features which help achieve this.
The mechanism is designed with four pairs of identical active and static latches. This allows the connector to reconnect at four equally spaced rotational orientations: 0, 90, 180, and 270 degrees.
The connector is genderless because each connector has both static and active latches. Any given connector faces can also connect to any other connector face.
When the connector is not activated, the active latches are able to retract completely below the surface of the connector. Protrusions prevent modules from being able to connect into corner configurations. Because the connector has a flush face, modules can be slid into place before activating the mechanism.
We used a load cell and custom built testing stand to progressively increase the load on the connectors to verify that we met our design specification.
The connector was able to successfully meet all load specifications.
Arriving at this point has taken many months of iteration.
Here is a brief gallery of some previous connector prototypes.
