Proportional-integral-derivative (p-i-d) Patents (Class 700/42)
  • Publication number: 20030097193
    Abstract: A position control system includes a PID controller for generating a current target value of a linear motor from a difference between a positional detected value and a positional command value, and a disturbance observer. The disturbance observer includes a signal processing unit comprising a filter for filtering a torque command value for a motor drive and an input torque estimating filter carrying out estimation for obtaining an estimated input load torque from the detected positional value. An inverse model of a motor torque constant calculates an estimated disturbance load torque from the difference between the filtered torque command value and the estimated input load torque and generates a correction value for the current target value so as to cancel a disturbance torque on the basis of the estimated disturbance load torque being calculated.
    Type: Application
    Filed: November 21, 2001
    Publication date: May 22, 2003
    Applicant: Sumitomo Heavy Industries, Ltd.
    Inventors: Kenichi Makino, Masayuki Yamamoto, Yoshiyuki Tomita
  • Patent number: 6560585
    Abstract: A procedure for controlling a complex dynamic process. According to the procedure, information is periodically acquired and values of recorded quantities are generated. The condition and the evolution of the process are described by a succession of detected process phenomena. Each process phenomenon that is detected as a function of its own context is judged, which itself is described by other process phenomena. Then, bits of information are directed to operators only when the judgment has determined that they are necessary and timely in the given context to help to maintain or to return the process to its production goals.
    Type: Grant
    Filed: July 3, 2000
    Date of Patent: May 6, 2003
    Assignee: Sollac
    Inventors: Marc Le Goc, Michel Barles, Norbert Dolenc, François-Marie Lesaffre, Claude Thirion
  • Publication number: 20030040814
    Abstract: The invention relates to a method for the control of mechanisms and technical systems characterized by that
    Type: Application
    Filed: April 4, 2002
    Publication date: February 27, 2003
    Inventors: Volker Moebius, Knut Grossmann
  • Publication number: 20030036812
    Abstract: A method and system are invented for adaptively and automatically retuning a closed-loop servo motor that is operating within normal limits. A first active set of configurable tuning constants is assigned to the servo motor, and motor performance is periodically measured to determine if performance is outside a retuning threshold, in which case the active set of configurable tuning constants is replaced by selecting a replacement set of tuning constants from a finite group of discrete predesigned sets of tuning constants. Actual performance of the servo motor is remeasured, and this process is repeated if the performance remains outside the retuning threshold. The predesigned sets of tuning constants are derived and stored in the servo motor software, typically as a result of pretesting the servo motor model by the manufacturer, for example using manual retuning.
    Type: Application
    Filed: August 15, 2001
    Publication date: February 20, 2003
    Applicant: Pitney Bowes Incorporated
    Inventors: Bernard J. Christ, Egbert E. Most, Peter K. Zanger
  • Patent number: 6501998
    Abstract: A method is described for the closed-loop control of a time-delayed process having compensation, in particular for temperature control. After a setpoint value step-change, the manipulated variable is set at a first constant value in an open-loop controlled operation, an IT1 model is identified on the basis of the step-change response and a PI controller is parametrized, which closed-loop controls the process into a second steady state. Subsequently, a more exact process model having compensation is determined and is used for the control adjustment.
    Type: Grant
    Filed: April 3, 2000
    Date of Patent: December 31, 2002
    Assignee: Siemens Aktiengesellschaft
    Inventor: Bernd-Markus Pfeiffer
  • Patent number: 6496749
    Abstract: A semiconductor producing apparatus is capable of quickly and accurately changing a controlled variable to a target value to thereby make the controlled variable quickly follow the target value. Moreover, the controlled variable and target value can be adjusted automatically, thus improving the productivity of a process. The semiconductor producing apparatus includes a PID adjustment section to which a target value and a detected control value are inputted through an adder, a pattern generation section having an approximate function for calculating a pattern output and making it possible to change the pattern output in accordance wit parameter values of the approximate function, and a switcher for switching between an output including at least an output of the pattern generation section and an output of the PID adjustment section to thereby generate an output.
    Type: Grant
    Filed: October 6, 1999
    Date of Patent: December 17, 2002
    Assignee: Kokusai Electric Co., Ltd.
    Inventors: Hideto Yamaguchi, Kazuo Tanaka, Kenzo Urabe
  • Publication number: 20020173862
    Abstract: Methods of designing the structure of multiple-input multiple-output (MIMO) PID controllers and methods of finding the optimal values for the MIMO PID parameters are disclosed. The optimal values of MIMO PID parameters are obtained by using an optimization algorithm which minimizes the largest modulus of all poles or the discrete time closed loop transfer function from set point SP to process variable PV, with or without user prescribed constraints on the PID parameters. Methods of designing the structure of single-input single-output (SISO) PID controllers and methods of finding tile optimal values for SISO PID parameters are also disclosed as special MIMO PID controller cases.
    Type: Application
    Filed: February 25, 2002
    Publication date: November 21, 2002
    Inventors: Danyang Liu, Wuyang Liu
  • Patent number: 6480750
    Abstract: A controlling system having a controller which acts on a controlled system as a function of a manipulated variable and a number of controller parameters is intended to provide a given control quality and a given control response in all operating states of the controlled system. For this purpose, the response characteristic of the controlled system is determined in a given time window during operation of the controller by comparing a wavelet transformation of the temporal response of the manipulated variable with a wavelet transformation of the temporal response of a controlled variable of the controller. An instant assigned to the respective wavelet transformation is detected, and the or each controller parameter is set as a function of the response characteristic.
    Type: Grant
    Filed: January 8, 2001
    Date of Patent: November 12, 2002
    Assignee: Siemens Aktiengesellschaft
    Inventor: Rainer Junk
  • Publication number: 20020151987
    Abstract: The invention is a method and apparatus for interconnecting a plurality of control systems used to planarize wafers in a CMP tool. Example control systems that may be used with the invention are the back-fill pressure of a carrier, carrier down-force, carrier rotation and platen rotation. A controller is used to automate the CMP tool by communicating desired set-points to the various control systems. The instability or fluctuations in control systems caused by a desired change in one or more other control systems are reduced by allowing the affected control systems to receive information regarding the intended actions by the control systems that affect them. In this manner the affected control systems may take proactive steps to reduce fluctuations in their output caused by changes in the other control systems.
    Type: Application
    Filed: April 13, 2001
    Publication date: October 17, 2002
    Inventor: Rafael Mendez
  • Publication number: 20020133243
    Abstract: A circuit implementing a non-integer order dynamic system includes a neural network that receives at least one input signal and generates therefrom at least one output signal. The input and output signals are related to each by a non-integer order integro-differential relationship through the coefficients of the neural network. A plurality of such circuits, implementing respective non-integer order controllers can be interconnected in an arrangement wherein any of the integral or differential blocks included in one of these circuits generates a signal which is fed to any of the integral or differential blocks of another circuit in the system.
    Type: Application
    Filed: December 26, 2001
    Publication date: September 19, 2002
    Applicant: STMicroelectronics S.r.l.
    Inventors: Salvatore Abbisso, Riccardo Caponetto, Olga Diamante, Domenico Porto, Eusebio Di Cola, Luigi Fortuna
  • Patent number: 6445962
    Abstract: An auto-tuner for use in tuning a control element in a process control network having distributed control functions includes a first tuning element located in the field device in which the control element is operating and a second tuning element located in a different device that communicates with the first device via a communication network. The first tuning element controls the operation of the control element during the dynamic data capture phase of an auto-tuning procedure, collects data during this phase of the auto-tuning procedure and determines one or more process characteristics from the collected data. The first tuning element then communicates the determined process characteristics to the second tuning element via the communication network.
    Type: Grant
    Filed: March 15, 1999
    Date of Patent: September 3, 2002
    Assignee: Fisher Rosemount Systems, Inc.
    Inventors: Terrence L. Blevins, Dennis L. Stevenson, Wilhelm K. Wojsznis
  • Publication number: 20020107604
    Abstract: A method is provided, the method comprising measuring at least one parameter characteristic of rapid thermal processing performed on a workpiece in a rapid thermal processing step, and modeling the at least one characteristic parameter measured using a first-principles radiation model. The method also comprises applying the first-principles radiation model to modify the rapid thermal processing performed in the rapid thermal processing step.
    Type: Application
    Filed: December 6, 2000
    Publication date: August 8, 2002
    Inventors: Terrence J. Riley, William Jarrett Campbell
  • Publication number: 20020107585
    Abstract: Systems and methods of operating the same are introduced for populating and using lookup tables with process facility control systems and models of the same. An exemplary computer system for use with a process facility having a plurality of associated processes, and includes both a memory and a processor. The memory is capable of maintaining (i) a data structure having a plurality of accessible fields and (ii) a model of at least a portion of the plurality of associated processes. The model may include a mathematical representation of at least a portion of the at least one process, defining certain relationships among inputs and outputs of the at least one process. The processor is capable of populating ones of the plurality of accessible fields of the data structure using the model iteratively with a range of possible values of the at least one measurable characteristic.
    Type: Application
    Filed: September 24, 2001
    Publication date: August 8, 2002
    Applicant: Honeywell, Inc.
    Inventor: Z. Joseph Lu
  • Patent number: 6424873
    Abstract: A control apparatus is disclosed that comprises a primary proportional, integral, differential (“PID”) controller capable of receiving a first setpoint and a first process variable and generating therefrom a second setpoint; and a secondary controller capable of receiving the second setpoint and a second process variable and generating therefrom an output control signal, wherein the primary PID controller is capable of receiving from the secondary controller a feedback signal 1) that indicates that a previous value of the second setpoint exceeds a limit associated with an output control signal of the secondary controller, and 2) that transfers a value of a signal from the secondary controller. The primary PID controller is then capable of limiting the contribution of the integral calculation component in a PID calculation that generates a new current value of the second setpoint.
    Type: Grant
    Filed: December 30, 1999
    Date of Patent: July 23, 2002
    Assignee: Honeywell Inc.
    Inventor: Frank J. Przybylski
  • Patent number: 6408228
    Abstract: The present invention provides a sequencing control strategy for environmental system controllers that takes better advantage of the capabilities of the system elements to enhance performance and reduce operating costs. Digital controller technology is included and operates in accordance with a state transition diagram clarifying conditions that must exist for the environmental controller to switch from one mode of operation to another (e.g., from a cooling mode with dampers set at the minimum position to a cooling mode with the dampers modulating to reduce the energy used for mechanical cooling). Several a controllers, or a single controller operating on several sets of control parameters, sequentially operate in accordance with transition data and system performance characteristics for controlling system operation.
    Type: Grant
    Filed: August 13, 1999
    Date of Patent: June 18, 2002
    Assignee: Johnson Controls Technology Company
    Inventors: John E. Seem, Gaylon M. Decious, Carol Lomonaco, Alex Bernaden
  • Patent number: 6378672
    Abstract: A hybrid active vibration isolation device has an intermediate plate inserted between a vibration damping subject and a setting surface on which the vibration damping subject is set, and laminated rubber and electromagnetic motors are interposed between the vibration damping subject and intermediate plate. A piezoelectric element is interposed between the intermediate plate and setting surface. In order to detect vibrations of the vibration damping subject, intermediate plate, and setting surface, velocity sensors are provided to them. The active vibration isolation device has a feedback mechanism for controlling the electromagnetic motors on the basis of signals from the velocity sensors provided to the vibration damping subject and setting surface, and controlling the piezoelectric element on the basis of a signal from the velocity sensor set on the intermediate plate.
    Type: Grant
    Filed: October 6, 1999
    Date of Patent: April 30, 2002
    Assignee: Canon Kabushiki Kaisha
    Inventor: Shinji Wakui
  • Publication number: 20020040250
    Abstract: A method and apparatus for automatically adjusting the gains of a feedback controller while the process continues to run and the controller continues to operate and control the process is disclosed. A desired closed-loop control bandwidth and a target loop transfer function are specified by the operator, and the tuning is accomplished automatically with minimal operator intervention and without the need for developing a model of the process. The automatic tuner subjects the process to one or more disturbance and the operation of both the process and the controller are monitored.
    Type: Application
    Filed: August 21, 2001
    Publication date: April 4, 2002
    Inventors: Sujit V. Gaikwad, Sachindra Kumar Dash, Kostas S. Tsakalis, Gunter Stein
  • Patent number: 6353766
    Abstract: Setting parameters of a PID controller are obtained by feeding a step signal or another input signal to an assigned controlled system. The response signal emitted by the controlled system is sampled and the characteristics of the Bode diagram are generated from the input signal and the response signal by using a smoothing method and elementary correspondences. The characteristics are normalized and input values are derived therefrom for a neural network which is trained on the properties of the controlled systems. The neural network directly generates the setting parameters for the controller.
    Type: Grant
    Filed: August 10, 1998
    Date of Patent: March 5, 2002
    Assignee: Siemens Aktiengesellschaft
    Inventor: Klaus Weinzierl
  • Patent number: 6343235
    Abstract: A PID controller has a parallel arrangement of a P-element, an I-element, and a D-element coupled to a first summation point for adding their respective output signals, a summation signal produced by the first summation point being employed for control of a variable. An actual value of the controlled variable is inputted to the parallel arrangement of the P-element, the I-element, and the D-element. The I-element is a series arrangement of a weighting section followed by an integrator, the I-element being coupled to the weighting section by a second summation point. The controller applies a time derivative of the actual value of the controlled variable to the second summation point, the second summation point subtracting the derivative from a signal outputted by the weighting section of the I-element.
    Type: Grant
    Filed: January 14, 1999
    Date of Patent: January 29, 2002
    Assignee: Mannesmann Rexroth AG
    Inventors: Detlef Hausen, Gerold Liebler, Dieter Sachs
  • Patent number: 6330484
    Abstract: A system and method for automatically tuning a fuzzy logic process controller is presented. A process under control is automatically assessed to determined process control characteristics including, for example, ultimate gain, ultimate period and time delay. Then, these quantities are used to calculate tunable control parameters which include scaling factors, which are applied to the fuzzy logic controller in order to optimize the performance of the fuzzy logic controller when connected to control the process.
    Type: Grant
    Filed: August 11, 1993
    Date of Patent: December 11, 2001
    Assignee: Fisher-Rosemount Systems, Inc.
    Inventor: S. Joe Qin
  • Patent number: 6317637
    Abstract: A PID control system and method which maintains continuity of the control output in spite of changes in controller parameters. The controller parameters include a proportional gain, an integral gain, a derivative gain, and a manual/automatic mode parameter. The control output at the time of a parameter change is set equal to the previous controller output, and the integrated error is set to a value consistent with the previous controller output according to a PID controller equation. This value for the integrated error serves to ensure the sustained continuity of the control output after the controller parameter change. Alternatively, the control output at the time of a parameter change is set equal to a first value continuous with respect to one or more previous control output values, and the integrated error is set to a value consistent with the first value according to the PID controller equation. Furthermore, the system and method employs integrator anti-windup. If the control output saturates, i.e.
    Type: Grant
    Filed: October 22, 1998
    Date of Patent: November 13, 2001
    Assignee: National Instruments Corporation
    Inventor: John Limroth
  • Patent number: 6314327
    Abstract: A system and method for calculating a future function value, such as velocity, for an object, from derivative values, such as acceleration, includes a sensor, such as an accelerometer, coupled to an object, such as a car. By predetermining a sampling rate of the derivative values and determining the highest frequency in the sampled signal, a set of prediction coefficients can be derived for use in a prediction formula which generates the future function value. A processor, which derives the prediction coefficients and implements the prediction formula may use the future function value to control operation of the object or a related object. By including a past function value in the prediction formula, a highly accurate future function value can be determined.
    Type: Grant
    Filed: April 28, 1998
    Date of Patent: November 6, 2001
    Assignee: The University of Akron
    Inventors: Dale H. Mugler, Yan Wu
  • Patent number: 6308106
    Abstract: A system controller for a controllable system having an inherent time delay includes a delay module that receives a command input and provides a first output signal delayed in time from the command input. A feed-forward module also receives the command input, or a function thereof, and provides a second output signal intended to drive the system to a desired state. A first summer receives the delayed output signal and a feedback signal from the controllable system. The first summer combines the delayed signal and the feedback signal to provide a third output signal. A compensator module receives the third output signal and provides a fourth output signal. A second summer receives the second output signal and the fourth output signal. The second summer combines the second output signal and the fourth output signal to provide an input signal for the controllable system.
    Type: Grant
    Filed: February 2, 1999
    Date of Patent: October 23, 2001
    Assignee: MTS Systems Corporation
    Inventors: Masoud Ameri, Donald A. Yost
  • Publication number: 20010032026
    Abstract: A process control system in a multi-input/output coordinate control system for executing coordinate control of a main input. The process control system includes operating point setting means for setting an operating point set value for an operating point of an n-th control output, n-th output control means for generating the n-th control output to control the main input based on the n-th control output, and m-th output control means for generating an m-th control output to control the operating point of the n-th control output so that the operating point of the n-th control output becomes equal to the operating point set value, thereby to allow the n-th control output of fast response to operate at the operating point set value by controlling the main input.
    Type: Application
    Filed: March 13, 2001
    Publication date: October 18, 2001
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Takashi Shigemasa, Akimoto Kamiya
  • Patent number: 6278902
    Abstract: A DSP of a servo control circuit obtains a movement value of a servomotor for each axis for each position-speed feedback processing cycle in accordance with a move command value for each axis delivered from a main processor with every distribution cycle, and also obtains a position correction value in accordance with pressure information detected by a sensor. The DSP of the servo control circuit carries out position-speed feedback processing with the use of a move command value which is obtained by correcting the movement value with the obtained position correction value, and drives the servomotor.
    Type: Grant
    Filed: March 3, 1999
    Date of Patent: August 21, 2001
    Assignee: Fanuc Ltd.
    Inventors: Yoshiki Hashimoto, Minoru Enomoto
  • Patent number: 6266580
    Abstract: A deviation between a target value of a quantity of state and an actual value of the quantity of state that is caused to follow the target value or a time-integral of the deviation is filtered. Based on the filtered value, a switching surface &sgr; is calculated. Based on a value of the switching surface &sgr;, a control input value u is outputted. The filter is set through comparison in Bode diagrams between a design model of a control system based on an ordinary sliding mode control method and a characteristic variation model of the control system, and by performing compensation in such a direction as to cancel out the variation. The filtering process makes it possible to properly control the control system having a dead time by the sliding mode control method.
    Type: Grant
    Filed: May 24, 2000
    Date of Patent: July 24, 2001
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Norimi Asahara, Masami Kondo, Toshinari Suzuki, Katsumi Kono, Ryoichi Hibino, Eiichi Ono, Masataka Osawa, Yuji Muragishi
  • Patent number: 6226557
    Abstract: A method for the closed-loop control of a nonlinear controlled system in which a state variable of the controlled system is determined and an actuating value is determined using a control method and a reference variable. In addition, by using the state variable of the controlled system, a correction value is read from a linearization characteristic curve and multiplied by the actuating value and the product is specified as new desired value for the controlled system. The linearization characteristic curve is chosen in such a way that multiplication of the linearization characteristic curve by the nonlinear control action of the controlled system yields a linear control action.
    Type: Grant
    Filed: July 29, 1998
    Date of Patent: May 1, 2001
    Assignee: Siemens Aktiengesellschaft
    Inventors: Andreas Hartke, Achim Przymusinski, Dirk Heinitz
  • Patent number: 6181976
    Abstract: A coefficient generator, data processing system and method of data reduction in correspondence with multiple-term parametric relationships, and particularly provides for data reduction in correspondence with approximative descriptions which include multiple dependent-variable terms whose higher order derivatives do not vanish. Forms of inverse of deviation variations are implemented to provide weighting which will correct for nonlinear function variations. The forms of inverse deviation weighting are implemented for representing forms of residual weighting and forms of implied squared residual weighting. Represented phases of function similation establish adept equations and implement forms of data processing and representing. Adept data processors correspondingly provide for characterizing approximating relationships in correspondence with provided data.
    Type: Grant
    Filed: April 8, 1998
    Date of Patent: January 30, 2001
    Inventor: Larry Stephen Chandler
  • Patent number: 6131076
    Abstract: A method and system for automatically establishing operational parameters of a statistical surveillance system. The method and system performs a frequency domain transition on time dependent data, a first Fourier composite is formed, serial correlation is removed, a series of Gaussian whiteness tests are performed along with an autocorrelation test, Fourier coefficients are stored and a second Fourier composite is formed. Pseudorandom noise is added, a Monte Carlo simulation is performed to establish SPRT missed alarm probabilities and tested with a synthesized signal. A false alarm test is then emperically evaluated and if less than a desired target value, then SPRT probabilities are used for performing surveillance.
    Type: Grant
    Filed: July 25, 1997
    Date of Patent: October 10, 2000
    Assignee: ARCH Development Corporation
    Inventors: Wegerich W Stephan, Kristin K. Jarman, Kenneth C. Gross
  • Patent number: 6081751
    Abstract: A system and method for automatically tuning a PID controller resident within a PID control loop. The PID control loop includes a PID controller and a process. The process supplies a process variable which is compared to the loop input. The result of the comparison is supplied to the PID controller, and the PID controller drives the process. A relay is applied to the loop input. The relay compares a set point value to the process variable. If the set point value is greater than the process variable, the relay drives the loop input with a first amplitude value. If the set point value is less than the process variable, the relay drives the loop input with a second amplitude value. In response to the set point relay, the process variable develops a sustained oscillation. The period and amplitude of the sustained oscillation are measured. A new set of PID controller parameters are calculated from the period and amplitude of sustained oscillation.
    Type: Grant
    Filed: April 3, 1998
    Date of Patent: June 27, 2000
    Assignee: National Instruments Corporation
    Inventors: Rongfu Luo, S. Joe Qin, Dapang Chen
  • Patent number: 6078843
    Abstract: An apparatus and method for controlling a process using a neural network which operates as part of a closed loop control system. The state of the control system is defined by one or more process condition signals and monitored for a predetermined set of controller parameters. The output of the control system is one or more device control signals, used by a control device to alter a process being controlled. The neural network uses normalized values of process condition signals in combination with a predetermined set of controller parameters to produce correction control signals. The correction control signals are then used to the create device control signals. Proper normalization of at least one of the process condition signals using the throttling range set by the controller parameters is necessary. The remaining input signals must be normalized as well, but the method of normalization is not as critical, except to create a common range for all process condition signals input to the neural network.
    Type: Grant
    Filed: January 24, 1997
    Date of Patent: June 20, 2000
    Assignee: Honeywell Inc.
    Inventor: Gideon Shavit
  • Patent number: 6055459
    Abstract: A method of preventing windup in a PID controller when using a nonlinear gain parameter is disclosed that is used in the PID controller of a process control system. The PID controller is arranged to produce within a current execution cycle a Control Variable (CV) to a device that is controlling a process responsive to an input Process Variable (PV), a setpoint (SP), and a gain parameter (K). The present invention receives the PV, the SP, and the K and generates a proportional, integral, and derivative component of the deviation of the PV from the SP. The components so generated are used to calculate an incremental output CV for the current execution cycle. A current value of gain is next calculated by subtracting the value of the gain for the current cycle from the value of the gain from the previous cycle. Testing for a linear or nonlinear gain parameter is done next and, responsive to a nonlinear gain parameter, a nonlinear gain change component is calculated and added to the incremental output CV.
    Type: Grant
    Filed: August 22, 1997
    Date of Patent: April 25, 2000
    Assignee: Honeywell Inc.
    Inventor: Richard C. Lawrence
  • Patent number: 6041264
    Abstract: A deadband control assistant, operating as part of a control system, eliminates oscillation of a controlled process output around a desired setpoint. The deadband control defines a deadband range, and steady-state-stabilization-time for the process being controlled. When the process output is within the deadband range and oscillation around the setpoint occurs for the steady-state-stabilization-time, the error is set to zero. The control signal may simultaneously be set, or may settle to a fixed value. The deadband control assistant thus allows the process output to stabilize as close as possible to the desired setpoint. Normal process control may resume once the process output strays outside the deadband range.
    Type: Grant
    Filed: January 27, 1997
    Date of Patent: March 21, 2000
    Assignee: Honeywell Inc.
    Inventors: Richard A. Wruck, Gideon Shavit
  • Patent number: RE36926
    Abstract: A welding system includes an imaging system that takes frame by frame pictures of a weld puddle. The imaging system is located in the weld torch. From the images puddle length and width are determined. The length and width are applied against stored membership functions that cover a range of different weld current characteristics and the degree of membership of each dimension in those functions is determined, producing an alpha factor for each membership function. This provides a fuzzy current requirement. Stored values for moment and area for each membership function are multiplied by the alpha for the respective function. The total of the moments is divided by the total of the areas to produce a desired weld current. The weld head includes a weld wire feeder that is driven by a servo by which the wire can be feed along either side of the weld joint. The wire feeder is gear driven in such a way that it does not interfere with the optics in the weld torch. The optics include a strobe to illuminate the puddle.
    Type: Grant
    Filed: March 25, 1999
    Date of Patent: October 31, 2000
    Assignees: United Technologies Corporation, MTS Corporation
    Inventors: Mary A. Austin, Kenneth C. Dunne, Dag Lindland, Phillip L. Frey, Dean G. Hystad, Richard E. Nelson, Bradley D. Warner