Method and apparatus for automatically realigning a machine element to a predetermined position after power interruption
AssigneeCincinnati Milacron Inc.
InventorsWilliam Robert Weisgerber, Ralph Charles Taylor
Life of this patent
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Abstract
A method and apparatus are disclosed for automatically realigning a machine element to a predetermined position after an interruption of power to a drive mechanism coupled to the machine element. After the termination of power, the apparatus measures a displacement of the machine element during a predetermined period of time; and this displacement is stored in a nonvolatile memory. When power is restored to the drive mechanism, the apparatus is operative to automatically move the machine element back through a distance equal to the stored displacement. Consequently, the machine element realigns to the position it had before the power interruption.
Claims15
An apparatus for automatically realigning a machine element to a commanded position in response to a first signal representing an interruption of power to a drive mechanism connected to the machine element and a second signal representing a reapplication of power to the drive mechanism, said drive mechanism being controlled by a servomechanism circuit responding to a command signal representing the desired position of the machine element and producing a feedback signal representing the actual position of the machine element, the apparatus comprising:
- a. means responsive to the servomechanism circuit and the first signal for detecting an error signal representing the displacement of the machine element after the power interruption;
- b. means responsive to the detecting means for storing the error signal;
- and
- c. means responsive to the second signal and the error signal for producing a command signal to the servomechanism circuit to cause the machine element to move to the commanded position it had at the time of the interruption of power.
An apparatus for automatically realigning a machine element to a commanded position in response to a first signal representing an interruption of power to a drive mechanism connected to a machine element and a second signal representing a reapplication of power to the drive mechanism, said drive mechanism being controlled by a servomechanism circuit including
- 1. a reference signal generator for producing a reference signal,
- 2. a command signal generator for producing a command signal representing a desired position of the machine element,
- 3. a feedback transducer responsive to the reference signal and in mechanical communication with the machine element for producing a feedback signal representing the actual position of the machine element, and
- 4. a discriminator circuit connected to the command signal generator and the feedback transducer for producing an error signal representing the difference between the command and feedback signals, the apparatus comprising:
- a. means responsive to the first signal and the command signal generator for detecting a first command signal representing the desired position of the machine element at the time of the power interruption;
- b. means responsive to the servomechanism circuit for detecting a first error signal representing the displacement of the machine element over a period of time after the power interruption;
- c. a storage means responsive to the detecting means for storing the first command signal and the first error signal;
- d. means responsive to the second signal and the command signal generator for detecting a second command signal representing the position of the machine element upon the reapplication of power;
- and
- e. means responsive to the first and second command signals and the first error signal and connected to the command signal generator for producing a realign signal to cause the command signal generator to produce a third command signal to move the machine element to the commanded position which it had at the time of the interruption of power.
A method for automatically realigning a machine element to a commanded position in response to an interruption and subsequent reapplication of power to a drive mechanism connected to the machine element, said drive mechanism being controlled by a servomechanism circuit responsive to a command signal and a feedback signal produced by a feedback transducer in mechanical communication with the machine element, the method comprising the steps of:
- a. detecting the termination of power to the drive mechanism;
- b. detecting in response to the command and feedback signals a displacement signal representing the movement of the machine element after the termination of power;
- c. storing the displacement signal;
- d. reapplying power to the drive mechanism;
- e. generating a realignment signal in response to the displacement signal;
- and
- f. transferring the realignment signal to the servomechanism circuit thereby causing the machine element to move to the commanded position, it had at the time of the interruption of power.
A method responsive to the interruption of power to a drive mechanism connected to a machine element for automatically realigning the machine element to a predetermined position after the reapplication of power to the drive mechanism, said drive mechanism being controlled by a servomechanism circuit producing an error signal in response to a command signal and a feedback signal, said feedback signal being produced by a feedback transducer responsive to a reference signal and in mechanical communication with the machine element, the method comprising the steps of:
- a. detecting the termination of power to the drive mechanism;
- b. detecting in response to the command and reference signals a first command signal representing the desired position of the machine element at the termination of power;
- c. storing the first command signal;
- d. detecting after a period of time a first error signal in response to the command and feedback signals, said first error signal representing the displacement of the machine element after the termination of power;
- e. storing the first error signal;
- f. reapplying power to the drive mechanism;
- g. detecting in response to the command and reference signals a second command signal representing the current position of the machine element upon the reapplication of power;
- h. generating a realignment signal in response to the first and second command signals and the error signal;
- and
- i. transferring the realignment signal to the servomechanism circuit to move the machine element to the predetermined position.
A method for realigning a machine element to a predetermined position in response to an interruption and a subsequent reapplication of power to a drive mechanism connected to the machine element, said drive mechanism being controlled by a servomechanism circuit including in part a descriminator circuit for producing an error signal to the drive mechanism in response to
- 1. a command signal representing a desired position of the machine element and being produced by command signal generator, and
- 2. a feedback signal representing the actual position of the machine element and being produced by a feedback transducer responsive to a reference signal and in mechanical communication with the machine element, the method comprising the steps of:
- a. detecting the termination of power to the drive mechanism;
- b. detecting after a predetermined period of time a first error signal in response to the command and feedback signals, said first error signal representing a first displacement of the machine element during the predetermined period of time after the termination of power;
- c. storing the first error signal in a nonvolatile memory;
- d. detecting a request to reapply power to the drive mechanism;
- e. modifying the operation of the command signal generator to produce a first command signal equal to the feedback signal thereby producing a zero error signal;
- f. reapplying power to the drive mechanism;
- and
- g. generating a realignment signal in response to the first error signal;
- and
- h. transferring the realignment signal to the command signal generator to cause the machine element to move through a displacement equal in magnitude by opposite in sign to the first displacement.
A method responsive to the interruption of power to a drive mechanism connected to a machine element for automatically realigning the machine element to a commanded position in response to the reapplication of power to the drive mechanism, said drive mechanism being controlled by a servomechanism circuit including a discriminator circuit for producing an error signal to the drive mechanism in response to
- 1. a command signal representing a desired position of the machine element and being produced by a command signal generator, and
- 2. a feedback signal representing the actual position of the machine element and being produced by a feedback transducer responsive to a reference signal and in mechanical communication with the machine element, the method comprising the steps of:
- a. detecting the termination of power to the drive mechanism;
- b. detecting, in response to the command and reference signals, a first command signal representing the commanded position of the machine element upon the termination of power;
- c. storing the first command signal in a nonvolatile store;
- d. detecting after a period of time a first error signal in response to the command and feedback signals, said first error signal representing the displacement of the machine element during the period of time after the termination of power;
- e. storing the first error signal in the nonvolatile store;
- f. detecting a request to reapply power to the drive mechanism;
- g. aligning the command signal generator to produce a second command signal equal to the current feedback signal thereby producing a zero error signal;
- h. reapplying power to the drive mechanism in response to the zero error signal;
- i. detecting in response to the command and reference signals a current command signal representing the current position of the machine element upon the reapplication of power;
- j. generating a realignment signal in response to the first and current command signals and the first error signal;
- and
- k. transferring the realignment signal to the command signal generator to cause the machine element to move to the commanded position.
Dependencies are inferred from the claim text.