Articulated backhoe is a common structural type in hydraulic excavators, that is, the boom, stick and bucket are hinged with each other. Under the action of the hydraulic cylinder of the actuator, all parts swing around the hinge point to complete the main functions of boom excavation, stick lifting, bucket unloading and so on. In the process of excavator actuator action, the following points should be considered. Firstly, when the boom moves downward, the stick and bucket should be adjusted to the correct position, and the next excavation action should be carried out. When the boom moves upward, the working arm moves to the unloading position through the rotary device of the excavator, and the boom and bucket are controlled to cooperate to unload the soil. The working conditions of hydraulic excavators change greatly, such as the working objects and environmental conditions change constantly, so that the working load and working speed change frequently. This requires that the hydraulic cylinder and hydraulic motor as the actuator have stable pressure and flow characteristics when the main engine is in various main working processes. Secondly, the working arm is required to combine two main actions at the same time to make full use of the engine power and shorten the cycle time.
