Mechanical Linkages

The mechanical configuration of the arm is very similar to an industrial hydraulic backhoe loader arm with the three degrees-of-freedom corresponding to the three main linkages of a backhoe, those linkages being the swing, boom and stick. The linkages are connected to a rigid base with a 1600 lb. counterweight for stability. The linkages are driven by single-rod double acting hydraulic cylinders (Parker D2HXT23A) with a 2 inch bore and 1 and 3/8 inch diameter rod, and strokes of 11, 10 and 12 inches for the swing, boom and stick respectively. The three cylinders are connected to the tank and pump with 3/4 inch hose. The pump is of constant supply pressure type with a set pressure of 1000 psi.

An end effector is located at the end of the stick. The end effector allows the arm to pick up dumbell-type weights as a means of loading the arm. The weights are used to simulate an excavator with a bucket loaded with material. The weight used varies from 0-100 pounds.