Abstract: The present invention relates to a control apparatus for a construction machine such as a hydraulic shovel, and the control apparatus for a construction machine includes a revolving operation member for operating a construction machine revolving unit (14), a fluid pressure pump (2) and an accumulator (5) for accumulating working oil from the fluid pressure pump (2), a fluid pressure actuator (7) for driving the construction machine revolving unit (14) to revolve with the working oil from the fluid pressure pump (2) and the accumulator (5), a first control valve (8) interposed between the fluid pressure actuator (7) and the fluid pressure pump (2), a second control valve (11) for controlling an inflow condition of the fluid from the fluid pressure actuator (7) into the accumulator (5), and control means (9) including first valve control means (9a) for controlling the first control valve (8) and second valve control means (9b) for controlling the second control valve (11).

Abstract: A hydraulic pump control system is shown that can control the absorbing torque of a hydraulic pump with respect to the engine power for driving the hydraulic pump in a well-balanced manner, and reduce a deviation of an actual revolution number from a target revolution number of the engine. A torque of hydraulic pumps during operation is estimated from a pump pressure and first and second line pressures. Based on the estimated torque, an output torque of the hydraulic pumps is controlled so that an error between a target revolution number and an actual revolution number of the engine becomes null.

Abstract: A system for controlling the cutting operation of a hydraulic backhoe having a bucket pivotally joined to one end of an arm, the other end of which is pivotally joined to one end of a boom having another end pivotally supported on a self propelled vehicle. Hydraulic jacks are provided for pivoting the boom relative to the vehicle, the arm relative to the boom, and the bucket relative to the arm. During each cutting operation the actual bucket speed relative to the arm and the actual arm speed relative to the boom are sensed and referred to a set of fuzzy control rules for obtaining command values for controlling the boom, arm and bucket jacks. The fuzzy control rules are so determined and utilized as to enable the machine to automatically take a cut in a manner suiting the hardness or other characteristics of the soil.