Numerical control method for correcting machine tool path errors

Claim 2

A numerical control method for controlling a machining path of a tool in accordance with a first machining path data denoting an instructed machining path from a machine program, a first feed speed data denoting an instructed feed speed from the machine program, and a first path error data denoting a prespecified tolerable path error, said method comprising the steps of: determining a second feed speed data which causes a machining path error that is N times as large as that of the first path error data when the machining path of the tool is driven according to the first machining path data, N being determined in advance; predicting an actual machining path of the tool according to the first machining path data and the second feed speed data; determining a second path error data according to a difference between the predicted actual machining path and the first machining path data; obtaining a first positional correction data by subtracting the first path error data from the second path error data; calculating a second machining path data by adjusting the first machining path data by an amount corresponding to the first positional correction data in a direction opposing a direction in which a path error occurs; calculating an amount of movement per unit of time in accordance with the second machining path data and the second feed speed data; driving the machine tool according to the calculated amount of movement per unit of time; and, detecting an actual machining path of the driven machine tool, calculating an actual follow-up lag data between the detected actual machining path and the second machining path data, and correcting the second feed speed data according to the actual follow-up lag data and the first path error data.

Claim 3

A numerical control method for controlling a machining path of a tool in accordance with a first machining path data denoting an instructed machining path from a machine program, a first feed speed data denoting an instructed feed speed from the machine program, and a first path error data denoting a prespecified tolerable path error, said method comprising the steps of: determining a path error prediction coefficient according to a directional rate of change of the first machining path data; predicting an actual machining path of the tool according to the first machining path data and the first feed speed data; determining a second path error data according to a difference between the predicted actual machining path and the first machining path data; obtaining a first positional correction data by subtracting the first path error data from the second path error data; obtaining a second positional correction data by multiplying the first positional correction data by the path error correction coefficient; calculating a second machining path data by adjusting the first machining path data by an amount corresponding to the second positional correction data in a direction opposing a direction in which a path error occurs; calculating an amount of movement per unit of time in accordance with the second machining path data and the first feed speed data; driving the machine tool according to the calculated amount of movement per unit of time; and, detecting an actual machining path of the driven machine tool, calculating an actual follow-up lag data between the detected actual machining path and the second machining path data, and correcting the first feed speed data according to the actual follow-up lag data and the first path error data.

Claim 4

A numerical control method for controlling a machining path of a tool in accordance with a first machining path data denoting an instructed machining path from a machine program, a first feed speed data denoting an instructed feed speed from the machine program, and a first path error data denoting a prespecified tolerable path error, said method comprising the steps of: determining a path error prediction coefficient according to a directional rate of change of the first machining path data; predicting an actual machining path of the tool according to the first machining path data and the first feed speed data; determining a second path error data according to a difference between the predicted actual machining path and the first machining path data; obtaining a first positional correction data by subtracting the first path error data from the second path error data; obtaining a second positional correction data by multiplying the first positional correction data by the path error correction coefficient; calculating a second machining path data by adjusting the first machining path data by an amount corresponding to the second positional correction data in a direction opposing a direction in which a path error occurs; calculating an amount of movement per unit of time in accordance with the second machining path data and the first feed speed data; driving the machine tool according to the calculated amount of movement per unit of time; and, detecting an actual machining path of the driven machine tool, calculating an actual follow-up lag data between the detected actual machining path and the second machining path data, and correcting the first feed speed data according to the actual follow-up lag data and the first path error data.

Claim 5

A numerical control method for controlling a machining path of a tool in accordance with a first machining path data denoting an instructed machining path from a machine program, a first feed speed data denoting an instructed feed speed from the machine program, a first path error data denoting a prespecified tolerable path error, and first tolerable positional correction data, said method comprising the steps of: determining a second feed speed data which causes a machining path error that is within a sum of the first tolerable positional correction data and the first path error data when the machining path of the tool is driven according to the first machining path data; predicting an actual machining path of the tool according to the first machining path data and the second feed speed data; determining a second path error data according to a difference between the predicted actual machining path and the first machining path data; obtaining a first positional correction data by subtracting the first path error data from the second path error data; calculating a second machining path data by adjusting the first machining path data by an amount corresponding to the first positional correction data in a direction opposing a direction in which a path error occurs; calculating an amount of movement per unit of time in accordance with the second machining path data and the second feed speed data; driving the machine tool according to the calculated amount of movement per unit of time; and, detecting an actual machining path of the driven machine tool, calculating an actual follow-up lag data between the detected actual machining path and the second machining path data, and correcting the second feed speed data according to the actual follow-up lag data and the first path error data.

Claim 6

A numerical control method for controlling a machining path of a tool in accordance with a first machining path data denoting an instructed machining path from a machine program, a first feed speed data denoting an instructed feed speed from the machine program, a first path error data denoting a prespecified tolerable path error, and first tolerable positional correction data, said method comprising the steps of: determining a second feed speed data which causes a machining path error that is within a sum of the first tolerable positional correction data and the first path error data when the machining path of the tool is driven according to the first machining path data; predicting an actual machining path of the tool according to the first machining path data and the second feed speed data; determining a second path error data according to a difference between the predicted actual machining path and the first machining path data; obtaining a first positional correction data by subtracting the first path error data from the second path error data; calculating a second machining path data by adjusting the first machining path data by an amount corresponding to the first positional correction data in a direction opposing a direction in which a path error occurs; calculating an amount of movement per unit of time in accordance with the second machining path data and the second feed speed data; driving the machine tool according to the calculated amount of movement per unit of time; and, detecting an actual machining path of the driven machine tool, calculating an actual follow-up lag data between the detected actual machining path and the second machining path data, and correcting the second feed speed data according to the actual follow-up lag data and the first path error data.

Claim 7

A numerical control method for controlling a machining path of a tool in accordance with a first machining path data denoting an instructed machining path from a machine program, a first feed speed data denoting an instructed feed speed from the machine program, a first path error data denoted a prespecified tolerable path error, and first tolerable positional correction data, said method comprising the steps of: determining a path error prediction coefficient according to a directional rate of change of the first machining path data; determining a second tolerable position data by multiplying the first tolerable positional correction data by the path error prediction coefficient; determining a second feed speed data which causes a machining path error that is within a sum of the second tolerable positional data and the first path error data when the machining path of the tool is driven according to the first machining path; determining a second path error data according to a difference between the predicted actual machining path and the first machining path data; obtaininga first positional correction data by subtracting the first path error data from the second path error data; calculating a second machining path data by adjusting the first machining path data by an amount corresponding to the first positional correction data in a direction opposing a direction in which a path error occurs; calculating an amount of movement per unit of time in accordance with the second machining path data and the second feed speed data; driving the machine tool according to the calculated amount of movement per unit of time; and, detecting an actual machining path of the driven machine tool, calculating an actual follow-up lag data between the detected actual machining path and the second machining path data, and correcting the second feed speed data according to the actual follow-up lag data and the first path error data.

Claim 8

A numerical control method for controlling a machining path of a tool in accordance with a first machining path data denoting an instructed machining path from a machine program, a first feed speed data denoting an instructed feed speed from the machine program, a first path error data denoted a prespecified tolerable path error, and first tolerable positional correction data, said method comprising the steps of: determining a path error prediction coefficient according to a directional rate of change of the first machining path data; determining a second tolerable position data by multiplying the first tolerable positional correction data by the path error prediction coefficient; determining a second feed speed data which causes a machining path error that is within a sum of the second tolerable positional data and the first path error data when the machining path of the tool is driven according to the first machining path; determining a second path error data according to a difference between the predicted actual machining path and the first machining path data; obtaininga first positional correction data by subtracting the first path error data from the second path error data; calculating a second machining path data by adjusting the first machining path data by an amount corresponding to the first positional correction data in a direction opposing a direction in which a path error occurs; calculating an amount of movement per unit of time in accordance with the second machining path data and the second feed speed data; driving the machine tool according to the calculated amount of movement per unit of time; and, detecting an actual machining path of the driven machine tool, calculating an actual follow-up lag data between the detected actual machining path and the second machining path data, and correcting the second feed speed data according to the actual follow-up lag data and the first path error data.