The invention provides a hydraulic
chassis engineering machine step control method, which includes testing the
current load state of the
engineering machine, the opening degree of the
throttle, and the actual run speed. The invention judges the
current load state, when the load state is intermediate low, and the difference of the actual speed and the goal rotate speed exceeds the preset range, then corresponding current can be provided for the
hydraulic motor for regulating the displacement; namely when the actual rotate speed is lower than the goal rotate speed, current for lowering the displacement can be provided to the
hydraulic motor; when the actual rotate speed is higher than the goal rotate speed, the current for improving the displacement can be provided to the
hydraulic motor; when the load state is in overload, the displacement of the hydraulic motor can be adjusted to the maximum. The required power of the
system can be calculated according to the current displacement of the hydraulic motor, the demand of the rotate speed, and the current pressure of the
system. Current, the displacement of which can meet the requirement of the controller, is provided for the
hydraulic pump according to the required power of the
system, and the needed displacement can ensure that the power absorbed by the
hydraulic pump can meet the requirement of the hydraulic motor. Compared with the prior art, the invention can enable the
engineering machine to realize the control requirement accurately.