Compound Pulley

This example shows a block and tackle system that is represented by the Belt Pulley and Cable blocks from the Simscape™ Driveline™ library. This compound pulley is rigged as a threefold purchase with two triple blocks. The system has a mechanical advantage of 6.

A payload of 10 metric tons subject to gravity is raised by an Ideal Velocity Source pulling on the cable end. The system starts at rest with the Velocity Source providing a force that is in equilibrium with the load. As the velocity source accelerates and decelerates, the cable tension increases and decreases, respectively.

Model

Simulation Results from Scopes

Simulation Results from Simscape Logging

These plots shows the pulley rotational velocities and cable segment tensions. Successive pulleys along the driveline rotate at slower velocities. Each cable segment supports a tension load that is one-sixth of the payload force. The cable tension increases as the paylod accelerates and decreases as the payload decelerates.