Method for generating axis control data for use in controlling a grinding machine and the like and system therefor

A method of generating axis control data (68) for use by first and second drive axis controllers (80, 76) to control first and second drive mechanisms (72, 70) respectively, of a grinding machine having a coordinate frame to control grinding of a camshaft (10) having a coordinate frame at a grinding station, the first drive mechanism moving a grinding wheel relative to the camshaft and the second drive mechanism rotating the camshaft, the method being characterized by the steps of:

• generating a kinematic model related to the coordinate frame of the camshaft to the coordinate frame of the grinding machine;
• generating a digital signal (108) related to the desired contour of the cam lift section of at least one non-circular (12 or 14) lobe on the camshaft to be ground at the grinding station to obtain digitized lift data;
• determining a differentiable, periodic equation (110) which approximates the lift data;
• and
• performing a conversion algorithm (128) with the kinematic model and the differentiable equation to obtain an axis control function (Eqs. 1 and 14) including a position control function for use in providing the axis control data for each of the controlled axes.

A method for controlling a grinding machine having a coordinate frame, the machine including first and second drive mechanisms (72, 70) to control grinding of a camshaft (10) having a coordinate frame at a grinding station, the first drive mechanism moving a grinding wheel relative to the camshaft and the second drive mechanism rotating the camshaft, the method comprising the steps of generating first and second feedback signals (82, 78) indicating the relative linear position of the grinding wheel with respect to the camshaft and the angular position of the camshaft, respectively, generating (133, 68, 84, 85) first and second reference signals, the first reference signal corresponding to the desired relative linear position of the grinding wheel with respect to the camshaft, and the second reference signal corresponding to the desired angular position of the camshaft in the coordinate frame of the grinding machine, comparing (90) the first and second feedback signals with their respective first and second reference signals to provide corresponding first and second control signals (106) to control the first and second drive mechanisms, respectively, the method being characterized by the steps of:

• generating a kinematic model relating the coordinate frame of the camshaft to the coordinate frame of the grinding machine;
• generating a digital signal (108) related to the desired contour of the cam lift section of at least one non-circular lobe (12 or 14) on the camshaft to be ground at the grinding station to obtain digitized lift data;
• determining a differentiable, periodic equation (110) which approximates the lift data;
• and
• performing a conversion algorithm (128) with the kinematic model and the differentiable equation to obtain an axis control function (Eqs. 1 and 14) including a position control function for each of the controlled axes of the grinding machine wherein the first and second reference signals are generated from their respective axis control functions.

A method of controlling a grinding machine having a coordinate frame and including first and second drive mechanisms (72, 70) to control grinding of a camshaft (10) having a coordinate frame at a grinding station, the first drive mechanism moving a grinding wheel relative to the camshaft and the second drive mechanism rotating the camshaft, the method comprising the steps of generating first and second reference signals (133, 68, 84, 85), the first reference signal corresponding to the desired relative linear position of the grinding wheel, and the second reference signal corresponding to the desired angular position of the camshaft in the coordinate frame of the grinding machine;

• comparing (90) the first and second feedback signals with their respective first and second reference signals to provide corresponding first and second control signals (106) to control the first and second drive mechanisms, respectively;
• the method being characterized by the steps of:
• generating a kinematic model relating the coordinate frame of the camshaft to the coordinate frame of the grinding machine;
• generating a digital signal (108) related to the desired contour of the cam lift section of at least one non-circular lobe (12 or 14) on the camshaft to be ground at the grinding station to obtain digitized lift data;
• and
• determining a differentiable, periodic equation (110) which approximates the lift data;
• performing a conversion algorithm (128) with the kinematic model and the differentiable equation to obtain an axis control function (Eqs. 1 and 14) including a position control function for each of the controlled axes of the grinding machine wherein the first and second reference signals are generated from their respective control functions and wherein one of the reference signals is generated in response to the feedback signal (86) of the other controlled axis (C-axis).

A method of controlling a machine tool having a coordinate frame and including first and second drive mechanisms (72, 70) to control machining of a workpiece (10) having a coordinate frame at a machining station, the first drive mechanism moving a work tool relative to the workpiece and the second drive mechanisms rotating the workpiece, the method comprising the steps of generating first and second feedback signals (82, 78) indicating the relative linear position of the work tool with respective to the workpiece and the angular position of the workpiece, respectively;

• generating first and second reference signals (133, 68, 64, 85), the first reference signal corresponding to the desired relative linear position of the work tool with respect to the workpiece, and the second reference signal corresponding to the desired angular position of the workpiece in the coordinate frame of the machine tool;
• comparing (90) the first and second feedback signals with their respective first and second reference signals to provide corresponding first and second control signals (106) to control the first and second drive mechanisms, respectively;
• the method being characterized by the step of:
• generating a kinematic model relating the coordinate frame of the workpiece to the coordinate frame of the machine tool;
• generating a digital signal (108) related to the desired contour of at least a portion (12, 14) of the workpiece to be machined at the machining station to obtain digitized machining data;
• determining a differentiable, periodic equation (110) which approximates the machining data;
• and
• performing a conversion algorithm (128) with the kinematic model and the differentiable equation to obtain an axis control function (Eqs. 1 and 14) including a position control function for each of the controlled axes of the machine tool wherein the first and second reference signals are generated from their respective control functions.

A method of controlling a machine tool having a coordinate frame including first and second drive mechanisms (72, 70) to control machining of a workpiece (10) having a coordinate frame at a machining station, the first drive mechanism moving a work tool relative to the workpiece and the second drive mechanism rotating the workpiece, the method comprising the steps of generating first and second feedback signals (82, 78) indicating the relative linear position of the work tool with respect to the workpiece and the angular position of the workpiece, respectively;

• generating first and second reference signals (133, 68, 84, 85), the first reference signal corresponding to the desired relative linear position of the work tool with respect to the workpiece, and the second reference signal corresponding to the desired angular position of the workpiece in the coordinate frame of the machine tool;
• comparing (90) the first and second feedback signals with their respective first and second reference signals to provide corresponding first and second control signals (106) to control the first and second drive mechanisms, respectively;
• the method being characterized by the steps of:
• generating a kinematic model relating the coordinate frame of the workpiece to the coordinate frame of the machine tool;
• generating a digital signal (108) related to the desired contour of at least a portion of the workpiece to be machined at the machining station to obtain digitized machining data;
• determining a differentiable, periodic equation (110) which approximates the machining data;
• and
• performing a conversion algorithm (128) with the kinematic model and the differentiable equation to obtain an axis control function (Eqs. 1 and 14) including a position function for each of the controlled axes of the machine tool;
• wherein the first and second reference signals are generated from their respective axis control function, and wherein one of the reference signals is generated in response to the feedback signal (86) of the controlled axis (C-axis).

A system for generating axis control data for use by first and second drive axis controllers (76, 80) to control first and second drive mechanisms (72, 70), respectively, of a machine tool having a coordinate frame to control machining of a workpiece (10) having a coordinate frame at a machining station, the first drive mechanism moving a work tool relative to the workpiece and the second drive mechanism rotating the work tool, the system being characterized by:

• means for generating a kinematic model relating the coordinate frame of the workpiece to the coordinate frame of the machine tool;
• means for storing (28 and 34) a digital signal related to the desired contour of at least one portion (12 or 14) of the workpiece to be machined at the machining station to obtain digitized machining data;
• means (28 and 110) coupled to said storing means for generating a differentiable, periodic equation which approximates the machining data;
• and
• means (28 and 128) for performing a conversion algorithm with the kinematic model and the differentiable equation to obtain an axis control function (Eqs. 1 and 14) including a position control function for use in providing the axis control data for each of the controlled axes.

A system for generating axis control data for use by first and second drive axis controllers (76, 80) to control first and second drive mechanisms (72, 70) respectively, of a grinding machine having a coordinate frame to control grinding of a camshaft (10) having a coordinate frame at a grinding station, the first drive mechanism moving a grinding wheel relative to the camshaft and the second drive mechanism rotating the camshaft, the system being characterized by:

• means for generating a kinematic model relating the coordinate frame of the camshaft to the coordinate frame of the grinding machine;
• means for storing (28 and 34) a digital signal related to the desired contour of the cam lift section of at least one non-circular lobe (12 or 14) on the cam shaft to be ground at the grinding station to obtain digitized lift data;
• means (28 and 110) coupled to said storing means for generating a differentiable, periodic equation which approximates the lift data;
• means (28 and 128) for performing a conversion algorithm with the kinematic model and the differentiable equation to obtain an axis control function (Eqs. 1 and 14) including a position control function for use in providing the axis control data for each of the controlled axes.

A system (26) for controlling a grinding machine having a coordinate frame including first and second drive mechanisms (72, 70) to control grinding of a camshaft (10) having a coordinate frame at a grinding station, the first drive mechanism moving a grinding wheel relative to the camshaft, the system comprising feedback means (82, 78) adapted to be coupled to the first and second drive mechanisms for generating first and second feedback signals (92) respectively, the first and second feedback signals indicating the relative linear position of the grinding wheel with respect to the camshaft and the angular position of the camshaft, respectively;

• reference signal generating means (68, 84, 85, 133) for generating first and second reference signals, the first reference signal corresponding to the desired relative linear position of the grinding wheel with respect to the camshaft, and the second reference signal corresponding to the desired angular position of the camshaft in the coordinate frame of the grinding machine;
• first and second drive axis controllers (80 and 76) coupled to said reference signal generating means and to said feedback means for comparing the first and second feedback signals with their respective first and second reference signals and to provide corresponding first and second control signals (106) to control the first and second drive mechanisms, respectively, the system being characterized by:
• means for generating a kinematic model relating the coordinate frame of the camshaft to the coordinate frame of the grinding machine;
• means for storing (28 and 34) a digital signal related to the desired contour of the cam lift section of at least one non-circular lobe (12 or 14) on the camshaft to be ground at the grinding station to obtain digitized lift data;
• means (28, 110) coupled to said storing means for generating a differentiable, periodic equation which approximates the lift data;
• and
• means (28, 128) for performing a conversion algorithm with the kinematic model and the differentiable equation to obtain an axis control function (Eqs. 1 and 14) including a position control function for each of the controlled axes of the grinding machine wherein the first and second reference signals are generated from their respective axis control function.

A system (26) for controlling a grinding machine having a coordinate frame including first and second drive mechanisms (72, 70) to control grinding of a camshaft (10) having a coordinate frame at a grinding station, the first drive mechanism moving a grinding wheel relative to the camshaft and the second drive mechanism rotating the camshaft, the system comprising feedback means (82, 78) adapted to be coupled to the first and second drive mechanisms for generating first and second feedback signals (92), respectively, the first and second feedback signals indicating the relative linear position of the grinding wheel with respect to the camshaft and the angular position of the camshaft, respectively;

• reference signal generating means (68, 85, 133) for generating first and second reference signals, the first reference signal corresponding to the desired relative linear position of the grinding wheel, and the second reference signal corresponding to the desired angular position of the camshaft in the coordinate frame of the grinding machine;
• first and second drive axis controllers (80, 76) coupled to said reference signal generating means and to said feedback means for comparing the first and second feedback signals with their respective first and second reference signals and to provide corresponding first and second control signals (106) to control the first and second drive mechanisms, respectively, the system being characterized by:
• means for generating a kinematic model relating the coordinate frame of the camshaft to the coordinate frame of the grinding machine;
• means for storing (28 and 34) a digital signal related to the desired contour of the cam lift section of at least one non-circular lobe (12 or 14) on the camshaft to be ground at the grinding station to obtain digitized lift data;
• means (28 and 110) coupled to said storing means for generating a differentiable, periodic equation which approximates the lift data;
• and
• means (28, 128) for performing a conversion algorithm with the kinematic model and the differentiable equation to obtain an axis control function (Eqs. 1 and 14) including a position control function for each of the controlled axes of the grinding machine, wherein the first and second reference signals are generated from their respective axis control functions and wherein said reference signal generating means is coupled to said feedback means so that one of said reference signals is generated in response to the feedback signal of the other controlled axis (C-axis).

A system (26) for controlling a machine tool having a coordinate frame including first and second drive mechanisms (70, 72) to control machining of a workpiece (10) having a coordinate frame at a machining station, the first drive mechanism moving a work tool relative to the workpiece and the second drive mechanism rotating the workpiece, the system comprising feedback means (82, 78) adapted to be coupled to the first and second drive mechanisms for generating first and second feedback signals (92), the first and second feedback signals indicating the relative linear position of the work tool with respect to the workpiece and the angular position of the workpiece, respectively;

• reference signal generating means (68, 84, 85, 133) for generating first and second reference signals, the first reference signal corresponding to the desired relative linear position of the work tool with respect to the workpiece, and the second reference signal corresponding to the desired angular position of the workpiece in the coordinate frame of the machine tool;
• first and second drive axis controllers (80, 76) coupled to said reference signal generating means and to said feedback means for comparing the first and second feedback signals with their respective first and second reference signals and to provide corresponding first and second control signals (106) to control the first and second drive mechanisms, respectively, the system characterized by:
• means for generating a kinematic model relating the coordinate frame of the workpiece to the coordinate frame of the machine tool;
• means for storing (28 and 34) a digital signal related to the desired contour of at least a portion of the workpiece to be machined at the machining station to obtain digitized machining data;
• means (28 and 110) coupled to said storing means for generating a differentiable, periodic equation which approximates the machining data;
• and
• means (28 and 128) for performing a conversion algorithm with the kinematic model and the differentiable equation to obtain an axis control function including a position control function for each of the controlled axes of the machine tool wherein the reference signals are generated from their respective axis control functions.

A system (26) for controlling a machine tool having a coordinate frame including first and second drive mechanisms (72, 70) to control machining of a workpiece (10) having a coordinate frame at a machining station, the first drive mechanism moving a work tool relative to the workpiece and the second drive mechanism rotating the workpiece, the system comprising feedback means (82, 78) adapted to be coupled to the first and second drive mechanisms for generating first and second feedback signals (92), respectively, the first and second feedback signals indicating the relative linear position of the work tool with respect to the workpiece and the angular position of the workpiece, respectively;

• reference signal generating means (68, 84, 85, 133) for generating first and second reference signals, the first reference signal corresponding to the desired relative linear position of the work tool with respect to the workpiece, and the second reference signal corresponding to the desired angular position of the workpiece in the coordinate frame of the machine tool;
• first and second drive axis controllers (80, 76) coupled to said reference signal generating means and to said feedback means for comparing the first and second feedback signals with their respective first and second reference signals and to provide corresponding first and second control signals (106) to control the first and second drive mechanisms, respectively;
• the system being characterized by:
• means for generating a kinematic model relating the coordinate frame of the workpiece to the coordinate frame of the machine tool;
• means for storing (28 and 34) a digital signal related to the desired contour of at least a portion of the workpiece to be machined at the machining station to obtain digitized machining data;
• means (28, 110) coupled to said storing means for generating a differentiable, periodic equation which approximates the machining data;
• and
• means (28, 128) for performing a conversion algorithm with the kinematic model and the differentiable equation to obtain an axis control function (Eqs. 1 and 14) including a position control function for each of the controlled axes of the machine tool wherein said reference signals are generated from their respective axis control function and wherein the reference signal generating means is coupled to the feedback means so that one of the reference signals (86) is generated in response to the feedback signal of the other controlled axis (C-axis).