This example models a ratchet lifter and demonstrates how to use contact proxies for contact problems that involve complex geometries.
In this example, as the traveler handle is pumped up and down, the traveler climbs up along the toothed rack to lift a load. To simplify the contacts between the toothed rack and climbers, the model represents the rack teeth and climber shaft-pins with proxies, such as cylinders and spheres, and simulates the contacts between these proxies.
The ratchet lifter consists of five subsystems: the Toothed Rack, Traveler, Neg Climber, Pos Climber, and Contact subsystems. The Pin Slot Joint block connects the toothed rack and traveler. The climbers are connected by the traveler and Spring and Damper Force block.
The Spatial Contact Force blocks that are used to model the contact forces between the climbers and rack teeth are housed in the Contact subsystems.
Animation and Proxies
The image shows the proxies of the rack teeth and climber cylinders.
This plot shows the position and velocity of the middle pin of the traveler.