Apparatus for controlling vibrational chatter in a machine-tool utilizing an updated synthesis circuit

An apparatus for controlling a machining operation wherein a workpiece and a machining tool are mounted in a machine structure and one of said workpiece and machining tool is moved with respect to the other to cause said tool to exert a machining force on said workpiece and to remove material therefrom, comprising first transducer means connected to one of said tool and said workpiece for detecting the actual motion thereof and for generating an electrical signal representative of said actual motion;

• a force signal generation circuit coupled to said first transducer means for acting on said motion signal to generate a force signal representative of the machining force;
• a synthesis circuit electrically coupled to said force signal generation circuit and to said first transducer means for generating a synthesized electrical signal representative of the motion in response to the machine force of the one of said tool and workpiece not connected to said first transducer means, said synthesis circuit having updating circuit means responsive to the signals generated by said force signal generation circuit and said first transducer means for continuously altering parameters of said synthesis circuit in accordance with changes in the static and dynamic characteristics of the workpiece;
• comparison means for comparing said motion signal generated by said first transducer means and said synthesized signal to generate an error signal in accordance with the compared signals;
• and a compensatory force actuator electrically coupled to said comparison means and mechanically coupled to said machine structure for delivering compensatory forces to the machine structure in response to said error signal to maintain said tool said workpiece in a predetermined spatial relationship during the machining process irrespective of any vibratory movements of said workpiece with respect to said tool.