A surgical system for transecting osseous tissue includes an ultrasonic waveform generator, a control unit, an ultrasonic instrument assembly including a electromechanical transducer and an ultrasonic blade, and a robotic system. The ultrasonic instrument assembly is attached to the robotic arm. The surgical system is configured so that the robotic arm moves the ultrasonic blade at a constant forward feed speed through the bone during a cutting operation and so that the forward motion is reduced, and preferably halted automatically upon a reduction in load per unit time or applied power, as monitored by a pickup or sensor.