US 5,659,480 AGranted

Method for coordinating motion control of a multiple axis machine

AssigneeIndustrial Service And Machine, Incorporated

InventorsRobb Gary Anderson, Robert D. Lorenz, Andrew Joseph Meyer

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Abstract

A multiple axis machine includes a plurality of servo-motors that produce movement of a member in at least two axes. The servo-motors are controlled by a computer which runs a simulation of a line shaft power train for producing movement of the member. Specifically, characteristics of a line shaft for powering the machine are defined along with characteristics of a pair of mechanical linkages with dynamically variable kinematics that are driven by the line shaft to produce movement along the two axes. The computer simulates a virtual line shaft using the line shaft characteristics and produces an angular acceleration, an angular velocity and an angular position of the virtual line shaft. The computer also simulates a pair of virtual mechanical linkages with dynamically variable kinematics based upon the linkage characteristics, and based on the angular acceleration, angular velocity and angular position of the virtual line shaft. The simulations produce control signals that operate actuators for each axis of the machine, and produce dynamically variable kinematic feedback force signals which are applied to the simulation of the virtual line shaft to simulate dynamically variable kinematic forces exerted by the mechanical linkages on the virtual line shaft.

Claims23

Dependent claims

A method for controlling a machine which has members that move with respect to first and second axes wherein movement with respect to each axis is produced by a separately powered actuator controlled by a computer and wherein movement along each axis is controlled in response to motion along another axis, said method comprising:

sensing a first position of machine movement with respect to the first axis;
determining a first velocity of machine movement with respect to the first axis;
sensing a second position of machine movement with respect to the second axis;
determining a second velocity of machine movement with respect to the second axis;
simulating on the computer a virtual line shaft which has variable states of shaft acceleration, shaft velocity and shaft position, wherein said simulating includes a virtual replication of relative stiffness of a mechanical line shaft;
simulating on the computer a virtual first mechanical linkage with dynamically variable kinematics which responds to the shaft acceleration, shaft velocity, shaft position, the first position and the first velocity, wherein simulating the virtual first mechanical linkage produces a first control signal for operating a first actuator of the machine and produces a first dynamically variable kinematic force feedback signal;
simulating on the computer a virtual second mechanical linkage with dynamically variable kinematics which responds to the shaft acceleration, shaft velocity and shaft position, the second position and the second velocity, wherein simulating the virtual second mechanical linkage produces a second control signal for operating a second actuator of the machine and produces a second dynamically variable kinematic force feedback signal;
operating the first actuator in response to the first control signal;
and
operating the second actuator in response to the second control signal;
wherein the step of simulating a virtual line shaft is responsive to the first and second dynamically variable kinematic force feedback signals.

8 more elements

A method for controlling a machine having members that move with respect to first and second axes wherein movement with respect to each axis is produced by a separately powered actuator controlled by a computer and wherein movement along each axis is controlled in response to motion along another axis, said method comprising steps of:

defining characteristics of a line shaft for powering the machine;
defining characteristics of a first mechanical linkage with dynamically variable kinematics that is driven by the line shaft to produce movement with respect to the first axis;
defining characteristics of a second mechanical linkage with dynamically variable kinematics that is driven by the line shaft to produce movement with respect to the second axis;
simulating a virtual line shaft on the computer using the characteristics of a mechanical line shaft including a virtual replication of relative stiffness, wherein the simulating produces an angular position value of the virtual line shaft, an angular velocity value of the virtual line shaft and an angular acceleration value of the virtual line shaft;
simulating a virtual first mechanical linkage on the computer using the characteristics of a first mechanical linkage, the angular velocity value of the virtual line shaft, the angular position value of the virtual line shaft, a first position .theta..sub.1 of machine movement with respect to the first axis, a first velocity .omega..sub.1 of machine movement with respect to the first axis, wherein simulating the virtual first mechanical linkage produces a first control signal for operating a first actuator of the machine and produces a first force feedback signal representing force applied by the virtual first mechanical linkage to the virtual line shaft;
operating the first actuator in response to the first control signal;
simulating a virtual second mechanical linkage on the computer using the characteristics of a second mechanical linkage, the angular velocity value of the virtual line shaft, the angular position value of the virtual line shaft, a second position .theta..sub.2 of machine movement with respect to the second axis, a second velocity .omega..sub.2 of machine movement with respect to the second axis, wherein simulating the virtual second mechanical linkage produces a second control signal for operating a second actuator of the machine and produces a second force feedback signal representing force applied by the virtual second mechanical linkage to the virtual line shaft;
and
operating the second first actuator in response to the second control signal;
wherein the step of simulating a virtual line shaft also is responsive to the first and second force feedback signals.

7 more elements

A method for controlling a machine which has members that move with respect to a plurality of n axes where n is a plural positive integer, and wherein movement along and about each axis is produced by a separately powered actuator controlled by a computer and wherein movement along and about each axis is controlled in response to motion with respect to other axes, said method comprising steps of:

(a) defining characteristics of a line shaft for powering the machine;
(b) for each one of the plurality of n axes defining characteristics of a separate mechanical linkage with dynamically variable kinematics that is driven by the line shaft to produce movement along one axis;
(c) simulating on the computer a virtual line shaft using the characteristics of the line shaft including a virtual replication of relative stiffness, wherein the simulating produces an angular acceleration value of the virtual line shaft, an angular velocity value of the virtual line shaft and an angular position value of the virtual line shaft;
(d) simulating on the computer a separate virtual mechanical linkage with dynamically variable kinematics for each one of the plurality of n axes using characteristics defined in step (b), an angular acceleration value of the virtual line shaft, the angular velocity value of the virtual line shaft, the angular position value of the virtual line shaft, a first position of machine movement with respect to one of the plurality of n axes, a first velocity of machine movement with respect one of the plurality of n axes, wherein the simulating of each virtual mechanical linkage produces a control signal for operating a servo-motor for an axis of the machine and produces a dynamically variable kinematic feedback force signal;
and
(e) controlling the servo-motors for each axis with control signals produced by step (d);
wherein the step of simulating a virtual line shaft also is responsive to dynamically variable kinematic force feedback signals produced by step (d).

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/495,284Filed 27 Jun 1995
Granted: 19 Aug 1997
Term ends: Not estimatedThe source records don’t support an estimate.

Classification11 codes

B23Q 5/40
Feeding continuously: by feed shaft, e.g. lead screw
B23Q 1/623
A single sliding pair followed perpendicularly by a single sliding pair: followed perpendicularly by a single rotating pair
B23Q 17/22
Arrangements for observing, indicating or measuring on machine tools: for indicating or measuring existing or desired position of tool or work
G05B 19/416
Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to…