SBIR Phase I: Novel Chatter Control Strategy for Machine Tools

This Small Business Innovation Research (SBIR) Phase I project will develop and implement a completely novel chatter control scheme. In many machine tools, fluid bearings (also known as hydrostatic and hydrodynamic bearings) are gaining popularity. The project will apply low-power piezo actuators to modulate the input flow rate of the fluid into the spindle housing. By carefully computing the actuator voltages, we can generate the correct amount of input flow rate so that the chatter effects will be minimized. There are several advantages associated with this new approach. First, since the fluid pressure is directly acting on the spindle unit, the response will be fast, direct, and effective. Second, since piezo is used to control the flow rate, not the whole-spindle housing, only very low power amplifiers are needed to regulate the flow. Third, the overall chatter control cost will be significantly reduced as commercial off-the-shelf, rather than custom designed, piezo actuators can be used. Fourth, no significant modification of the machine is needed because four small piezo actuators will be inserted near the inlets. Only a modest change in mechanical design needs to be done. The commercial application will provide a practical approach to chatter control. Chatter is the primary limiting factor in metal removal rate in machine tools. To a first order approximation, a machine tool with twice the metal removal rate is worth twice as much. This technology will be useful for other types of machine tools such as milling, lathe, and boring.