Boom Lift Crawler Jib with Hydraulic Actuation (Test Harness)

This example models a hydraulic system that extends a jib for a boom lift basket. A double-acting cylinder can raise or lower the jib. Counterbalance valves are used to ensure a controlled descent of the basket.

This model is a test harness from the main model (see documentation).

Contents

Model

Open Model

Component Under Test

The component under test is a hydraulic system to extends an actuator that raises a boom lift basket. A double-acting cylinder with two counterbalance valves extends to raise the jib. The counterbalance valves lock the cylinder in place when the 4-way valve returns to center. The lock persists if a hose upstream bursts so the boom does not collapse. The counterbalance in the valves keeps the cylinder from running ahead of the pump under gravity. This condition would cause it to ratchet if pilot operated check valves were used, as are shown in the outriggers.

Simulation Results: Jib Sequence

The plots below shows the result of a test sequence designed to raise and lower the jib. The test sequence includes signals for all valves so that the test sequence can also be run on the full model.

Below is the corresponding prescribed motion for the test. This allows testing on a full model that has motion for any combination of the actuators.

Motion of the lift, extend, and jib cylinders along with applied actuator force.

Hydraulic pressures in the actuators along with actuator position.

Simulation Results: Extend Sequence

The plots below shows the result of a test sequence designed to raise and lower the jib. In this test sequence, the tilt function is exercised to see how it affects jib actuation. The test sequence includes signals for all valves so that the test sequence can also be run on the full model.

Below is the corresponding prescribed motion for the test. This allows testing on a full model that has motion for any combination of the actuators.

Motion of the lift, extend, and jib cylinders along with applied actuator force.

Hydraulic pressures in the actuators along with actuator position.