Because the load of the working device of excavator is difficult to break, the paper studies its working state by indirect measurement, starting with the parameters of the boom, stick and bucket cylinder of hydraulic excavator, and determines the pressure parameters of the cylinder to obtain the digging resistance between the bucket teeth. Under the condition of stick excavation, the working device of excavator is the largest force arm from the stick to the boom, and the boom is prone to dangerous cross-section. Therefore, the working device excavation analysis is carried out under the working condition of bucket digging. Because of the one-way stress on the hydraulic cylinder, the curve relationship between the stress and time of each cylinder can be obtained by sticking strain gauge near the hinge point of each hydraulic cylinder. Measure points are arranged for the near hinge points of boom, stick and bucket cylinder piston rod near support. And the displacement sensor is arranged for the hydraulic cylinder side next to these measuring points.
