A tool for operating on a workpiece includes a motion actuator and a controller that responsively varies a speed of the motion actuator and an operating speed of a working surface. The controller is configured to respond to a derived force that is a function an applied force exerted by an operator to manageably adjust pressure on the working surface to achieve a rate of work. The controller changes simultaneously both a rate of work on the workpiece and the operating speed of the working surface according to a sensitivity profile. The simultaneous change of rate of work and operating speed is manageable under both acceleration and deceleration by the operator with the applied force. The sensitivity profile expresses a relationship of a monotonically increasing positive slope between the derived force and the operating speed of the working surface within the range.

A tool for operating on a workpiece includes a motion actuator and a controller that responsively varies a speed of the motion actuator and an operating speed of a working surface. The controller is configured to respond to a derived force that is a function an applied force exerted by an operator to manageably adjust pressure on the working surface to achieve a rate of work. The controller changes simultaneously both a rate of work on the workpiece and the operating speed of the working surface according to a sensitivity profile. The simultaneous change of rate of work and operating speed is manageable under both acceleration and deceleration by the operator with the applied force. The sensitivity profile expresses a relationship of a monotonically increasing positive slope between the derived force and the operating speed of the working surface within the range.