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Ratchet Leadscrew Mechanism

This example shows a stepping mechanism constructed from a self-locking leadscrew and a unidirectional clutch. The input shaft of the unidirectional clutch oscillates with velocity amplitude 2 rad/s and frequency 0.5 rad/s. The unidirectional clutch drives the load via the leadscrew. The lead angle of the screw is small enough to ensure self-locking operation due to geometry and thread friction. As a result, the load maintains its position while the clutch input shaft rotates in the opposite direction and the load moves in incremental steps of about 25 mm.


Simulation Results from Simscape Logging

The plot below shows the speed of the input shaft, leadscrew shaft, and the motion of the nut. The self-locking behavior of the leadscrew plus the unidirectional clutch enables the cyclical input motion to move the nut in a single direction.