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Blog Archive

Mechanical Department

Head of Mechanical Department: David Villegas Prados

The mechanical department oversees the design of the experiment’s supporting structure as well as the development of the chaff deployment system.
This releasing system consists of chaff capsules, each capsule is enclosed in a compartment and will have its own line attached - they will be placed a few centimeters outside the gondola. Each line is fixed to the capsule and to a different bobbin attached to the shaft in the upper level of the experiment. Each capsule is supported in position by a hinge acting as a trap-door. The movable part of the hinge is only supported by a thin rigid slab, which is directly connected to a servo motor. When the servo motor is activated, the slab is retracted, the hinge face is free to rotate and the capsule will fall.
Each line is well rolled up above the containers and when the signal is given to the servo-actuators. The material of the line is a very stiff material, to prevent from breaking when it reaches the stopping point.
Each chaff container is released individually, and the cables have different lengths to avoid direct collision. This means that the deployment sequence to be followed must be from the longest rope to the shortest.
The reeling up system consists of a DC motor, which will be activated once all the capsules are dropped. The capsules attached to the line will be rolled up around the shaft using one bobbin for each line. Therefore, the upper level of the realising system will be present in the releasing operation, since it has to absorb the shock of the falling capsule, and in the reeling operation when the motor is activated to pull the capsules up. On the other hand, the lower level of experiment will only operate in the releasing system when the slabs are retracted to let the capsule fall freely.
Three main challenges are identified from this department, which the team is working right now. The sizing of the servo motor actuation to “activate” the trap-door and let the containers fall. The geometry, weight distribution and opening mechanism of the capsules. And the sizing of the DC motor with the corresponding shaft, coupling and bobbins.

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