Data processing: generic control systems or specific application – Specific application – apparatus or process – Product assembly or manufacturing
Reexamination Certificate
1999-03-03
2001-08-07
Grant, William (Department: 2121)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Product assembly or manufacturing
C700S109000
Reexamination Certificate
active
06272391
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
BACKGROUND OF THE INVENTION
The present invention relates to industrial controllers for the real-time control of equipment used in manufacturing and in particular to an industrial controller that automatically organizes equipment for the manufacture of a products based on the capabilities of the equipment.
Industrial controllers are special purpose computers used in controlling industrial processes. Under the direction of a stored control program, an industrial controller examines a series of inputs reflecting the status of the controlled process and changes a series of outputs controlling the industrial process. The inputs and outputs may be binary, that is, on or off, or analog, providing a value within a continuous range. The inputs may be obtained from sensors attached to the controlled equipment and the outputs may be signals to actuators on the controlled equipment.
Unlike the standardized software normally executed on conventional computers, the control program executed on an industrial controller is normally unique to each controlled process. The writing and troubleshooting of the control program is thus a significant cost in the creation of an industrial control system. After the controlled program is complete, it must often be modified as the product to be manufactured changes or as equipment is exchanged, replaced or repaired.
The above referenced parent to this application describes a self-configuring industrial control system employing a number of autonomous control units, each associated with a particular piece of manufacturing equipment. The autonomous control units are programmed with data describing the capabilities of their equipment and the equipment's ability to interact with other equipment. A desired product is described in a “job description language” and broadcast to the autonomous control units, each which identifies portions of the job that they can complete. The autonomous control units then exchange bids and counterbids with the other autonomous control units to allocate the job among units and to select the desired operating parameters of the associated equipment. The autonomous control units are programmed with generalized goals so that the allocation may be further optimized for high productivity, low cost or some other objective measure.
The bidding process accommodates competing goals of the different pieces of equipment. Nevertheless, this bidding process can be quite time consuming and in certain instances, can disproportionately allocate resources to downstream equipment whose counterbids drive the ultimate job plan produced.
BRIEF SUMMARY OF THE INVENTION
The present invention simplifies the bidding process through the use of an initial exchange of operational constraints between each autonomous controller. In this exchange step, the autonomous controllers compare the ranges of their machines' inputs and outputs to the corresponding ranges of connected input and outputs of predecessor and successor machines. By internalizing these ranges, the bidding process is substantially simplified. Further, to the extent possible, inconsistencies in the ranges are remedied by producing new ranges rather than individual values. In this way, local choices in the optimization provided by the bidding process is preserved.
Specifically, the present invention provides an industrial control system for controlling an industrial process of interconnected machines operating to produce a manufactured product according to a job plan. The industrial control includes a plurality of interconnected autonomous control units, one associated with each machine, each having an electronic memory. The electronic memory holds data representing machine constraints indicating constraints on the operation of a given machine resulting from limitations of the machine and inter-machine relationships indicating physical operating parameters of the given machine linked to the physical operating parameters of another machine. An electronic computer executes a stored program to modify the machine constraints associated with the given machine by the machine constraints of a machine related by the inter-machine relationships and evaluates the feasibility of executing a portion of a job plan for the manufacture of a product by the given machine based on the modified machine constraints.
Thus, it is one object of the invention to provide each autonomous control unit with information about constraints that may be imposed on the job plan by other machines to which the given machine may be related, for example, by shared inputs or outputs. By bringing this information into each autonomous control unit, inefficient communication between the autonomous control units is minimized and a solution to the allocation of the job plan among machines is more rapidly obtained.
The memory may hold multiple machine constraints and multiple inter-machine relationships identified to different material paths between machines. The machine constraints associated with a given material path are modified by the machine constraints of only machines related by the inter-machine relationship associated with the given material path.
Thus, it is another object of the invention to address constraints imposed by adjacent machines without unduly limiting the solution sought by the autonomous control units. By segregating constraints according to machine paths, constraints applicable to one machine path are not necessarily imputed to other machine paths.
The electronic computer may respond to a job plan and bids by other autonomous control units to create a bid for the job plan describing performance of a portion of the job plan that may be performed by the given machine according to the modified machine constraints. In the alternative, the computer may create a counterbid proposing further modification of the machine constraints. Further in response to counterbids by other autonomous control units, the electronic computer may create a modified bid for the job plan according to the modified machine constraints adjusted by the received counterbid.
Thus, it is another object of the invention to provide a method of coordinating autonomous control units to exchange machine constraint ranges that may be used in conjunction with a bid and counterbid system for producing a particular value within those constraint ranges.
The inter-machine relationships may match identical operating parameters that are inputs or outputs of interconnected machines.
Thus it is yet another object of the invention to allow upstream machines to impose their constraints on downstream machines as well as downstream machines being able to impose their input constraints on upstream machines thereby improving knowledge of each machine as to the restraints of the overall process.
The machine constraints may be ranges of operating parameters for the given machine and the modification of the machine constraints may produce a multivalue range of operating parameters that is a subset of the range of operating parameters.
Thus it is another object of the invention to preserve the machine constraints as ranges of values rather than individual values to allow greatest freedom within an individual autonomous control unit for local optimization.
The foregoing and other objects and advantages of the invention will appear from the following description. In the description, reference is made to the accompanying drawings which form a part hereof and in which there is shown by way of illustration a preferred embodiment of the invention. Such embodiment does not necessary represent the full scope of the invention, however, and reference must be made to the claims herein for interpreting the scope of the invention.
REFERENCES:
patent: 5216593 (1993-06-01), Dietrich et al.
patent: 5280425 (1994-01-01), Hogge
patent: 5353229 (1994-10-01), Tanaka
patent: 5406476 (1995-04-01), Deziel et al.
patent: 5659478 (1997-08-01), Pennisi et al.
patent: 5808891 (1998-09-01), Lee et al.
patent: 5845258 (1998-12-01
Herr Rebecca J.
Maturana Francisco P.
Vasko David A.
Baxter Keith M.
Gerasimow Alexander M.
Grant William
Rapp Chad
Rockwell Technologies LLC
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