Abstract: A process for automatically controlling power excavators is disclosed. In the process, the motions of the working members in accordance with lever handling motions of an operator are stored in a controller and reproduced to approximately conduct the operation. The operational errors of the reproduced motions of the working members are corrected and compensated in accordance with newly inputted lever handling motions of the operator while approximately conducting the operation, thereby accomplishing the desired operation. The process optimally controls the excavators regardless of working conditions, thereby improving the operational precision of the excavators. The above process does not need to use any sensors.

Abstract: A device and process for controlling the automatic operations of a power excavator are disclosed. The device has a plurality of sensors for sensing the motions of the excavator's moving parts. The device also has a controller with discriminating means. The discriminating means operates the sensed data of the sensors and discriminates the automatic operation to be performed. The controller outputs the control signals to the excavator's moving parts for automatically performed the automatic operation. The control device further includes recognizable signal output means for converting the discriminated results into recognizable signals prior to outputting the discriminated results, and confirmation signal input means for confirming the discriminated results outputted from the recognizable signal output means.

Abstract: A method for controlling the RPM of an engine in a hydraulic construction machine. A reference throttle lever position value and a reference engine RPM value are set to allow the engine to have a target output characteristic. A first control arithmetic operation is performed in response to a present throttle lever position value and the set reference throttle lever position value to allow a difference between the present throttle lever position value and the set reference throttle lever position value to be within the range of a mechanical error of an engine throttle control mechanism. A first control signal is generated as a result of the first control arithmetic operation to control the RPM of the engine.