EXCAVATION CONTROLLING APPARATUS FOR DIPPER SHOVEL

An excavation controlling apparatus which can effect precise driving control off a dipper in accordance with an actual operation condition with a simple structure of a low cost. A dipper handle extension instruction calculation section calculates a dipper handle extension instruction signal from a difference between a moment upper limit value set by a moment limit value setting section and a working moment calculated by a working moment calculation section, and causes a dipper handle driving motor output controlling apparatus to control a sliding driving operation of a dipper handle in accordance with the dipper handle extension instruction signal. A hoisting operation instruction calculation section corrects a hoisting operation reference instruction set by a hoisting operation reference instruction setting section with the moment upper limit value and a hoisting operation instruction correction amount calculated from the working moment. A hoisting motor output controlling apparatus performs hoisting control based on the thus corrected hoisting operation instruction.