Process control system with reconfigurable expert rules and control modules

• US 5,006,992 A
• Filed: 09/30/1987
• Issued: 04/09/1991
• Est. Priority Date: 09/30/1987
• Status: Expired due to Term

• Current Assignee: Pavilion Technologies Incorporated (Rockwell Automation, Inc.)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Skeirik, Richard D.
• Primary Examiner(s): MACDONALD, ALLEN R
• Application Number:
  US07/103,014
• Time in Patent Office: 1,287 Days
• Field of Search: 364/513, 364/468, 364/469, 364/148-152, 364/191
• US Class Current: 706/58
• CPC Class Codes: G05B 13/028 using expert systems only
• CPC Class Codes: G06N 5/04 Inference or reasoning models
• CPC Class Codes: Y10S 706/906 Process plant

Abstract

An integrated system for process control in which a process supervisor procedure (which is preferably the top-level procedure) is configured as a modular software structure, with modules which can be revised by a user at any time, without significantly interrupting the operation of the process supervisor. The modular software structure can define control parameters for many process control procedures, and can retrieve data from many sources (preferably including a historical database of process data, which can provide time-stamped data). The supervisor can also call on various expert subprocedures. Preferably the expert subprocedures can also be modified by an authorized user at any time, by calling up and editing a set of natural-language rule templates which correspond to the rules being executed by the expert subprocedure.

Claims

1. A computer-based method for operating a substantially continuous process, comprising the steps of:

(1) operating the process with one or more sensors connected to sense conditions in the process, and one or more actuators connected to change conditions in the process;

(2) controlling one or more of said actuators with a process controller in accordance with signals received directly from one or more of said sensors and in accordance with one or more control parameters; and

(3) running a process supervisor procedure, comprising one or more software modules, for selectively defining one or more of said control parameters for said process controller, said process supervisor procedure also calling on at least one expert subprocedure which uses a knowledge base and inference structure relevant to the process.

2. The method of claim 1, wherein said knowledge base and inference structure of step (3) comprise the step of running a substantially real-time expert control procedure.

3. The method of claim 1, wherein said process controller of step (2) comprises the step of controlling said actuators substantially continuously in real time, and said expert subprocedure of step (3) comprises the step of not running continuously in real time.

4. The method of claim 1, wherein said process controller of step (2) comprises the step of using real-time logic, and said expert subprocedure of step (3) comprises the step of recurrently running as a batch process.

5. The method of claim 1, wherein said process controller of step (2) uses analog logic for controlling.

6. The method of claim 1, wherein respective data definitions comprise the step of defining said one or more software modules of step (3), including pointers to procedures which will carry out a respective function, and, for at least some of said software modules, parameters to be passed to said procedures pointed to.

7. The method of claim 1, wherein one or more of said control parameters of step (2) comprise the step of including goals of said process controller.

8. The method of claim 1, wherein said process controller of step (2) and said process supervisor procedure of step (3) comprise the step of using processes running on the same computer system.

9. The method of claim 1, wherein said process controller of step (2) and said process supervisor procedure of step (3) comprise the step of being part of the same software system.

10. The method of claim 1, wherein said expert subprocedure comprises the steps of:

(1) executing upon command from said process supervisor procedure;

(2) running under the control of a timing procedure; and

(3) preventing said process supervisor procedure from taking any further action until execution of said expert subprocedure is completed.

11. A computer-based method for operating a substantially continuous process, comprising the steps of:

(1) operating the process with one or more sensors connected to sense conditions in the process, and one or more actuators connected to change conditions in the process;

(2) controlling one or more of said actuators with a process controller in accordance with signals received from said sensors and in accordance with control parameters;

(3) running a process supervisor procedure for selectively defining one or more of said control parameters for said process controller, said supervisor procedure also calling on at least one expert subprocedure which uses a knowledge base and inference structure relevant to the process; and

(4) using an historical database containing at least one time-stamped data regarding the process, wherein said supervisor procedure or said expert subprocedure fetch at least one value from said historical database.

12. The method of claim 11, wherein said knowledge base and inference structure of step (3) comprise the step of defining a substantially real-time expert control procedure.

13. The method of claim 11, wherein one or more of said control parameters of step (2) comprise the step of including goals of said process controller.

14. A computer-based method for operating a substantially continuous process, comprising the steps of:

(1) operating the process with one or more sensors connected to sense conditions in the process, and one or more actuators connected to change conditions in the process;

(2) controlling one or more of said actuators with a process controller in accordance with signals received from said sensors and in accordance with control parameters;

(3) running a process supervisor procedure for selectively defining one or more of said control parameters for said process controller, said supervisor procedure also calling on at least one expert subprocedure which uses a knowledge base and inference structure relevant to the process; and

(4) selectively presenting to a user a functional structure for a new rule for said expert subprocedure and/or a functional structure corresponding to the user input from which a current version of said expert subprocedure was generated, and selectively compiling one or more user inputs from said functional structure into a new version of said expert subprocedure.

15. The method of claim 14, wherein said functional structure of step (4) comprises the step of including user-alterable portions which appear differently to said user than do other portions of said functional structure.

16. The method of claim 14, wherein said step of presenting functional structures includes presenting standardized data interface definitions such that the user can specify data having one of plural pre-defined temporal characteristics.

17. The method of claim 14, wherein said knowledge base and inference structure of step (3) comprise the step of defining a substantially real-time expert control procedure.

18. The method of claim 14, wherein one or more of said control parameters of step (2) comprise the step of including goals of said process controller.

19. A computer-based method for operating a substantially continuous process, comprising the steps of:

(1) operating the process with one or more sensors connected to sense conditions in the process, and one or more actuators connected to change conditions in the process;

(2) controlling one or more of said actuators with a process controller in accordance with signals received from said sensors and in accordance with control parameters;

(3) running a process supervisor procedure, comprising one or more software modules, for selectively defining one or more of said control parameters for said process controller, said process supervisor procedure also calling on at least one expert subprocedure which uses a knowledge base and inference structure relevant to the process;

(4) selectively presenting functional structures, to a user, for a new rule for said expert subprocedure and/or a functional structure corresponding to the user input from which a current version of said expert subprocedure was generated, and selectively compiling one or more user inputs from said functional structure into a new version of said expert subprocedure; and

(5) selectively presenting functional structures, to a user, for a new software module for said process supervisor procedure and/or a functional structure corresponding to a user input from which a current software module of said process supervisor procedure was generated, and selectively loading the user input from said functional structure to be used by said process supervisor procedure.

20. The method of claim 19, wherein said functional structure presented to the user in step (4) comprises the step of using a substantially natural language format.

21. The method of claim 19, wherein said functional structure presented to the user in step (4) comprises the step of using a substantially natural language format which is readily understandable by a user who is technically skilled in a predetermined art but who is not necessarily competent in any computer language.

22. The method of claim 19, wherein only restricted portions of said functional structure of step (4) comprises the step of allowing for user-alterability.

23. The method of claim 19, wherein said user-alterable portions of said functional structures appear differently to said user than do other portions of said functional structures.

24. The method of claim 19, wherein said step of presenting functional structure in step (4) further comprises the step of including presenting standardized data interface definitions such that the user can specify data having one of plural pre-defined temporal characteristics.

25. The method of claim 19, wherein said knowledge base and inference structure of step (3) comprises the step of defining a substantially real-time expert control procedure.

26. The method of claim 19, wherein respective data definitions comprise the step of defining said one or more software modules of step (3), including pointers to procedures which will carry out a respective function, and, for at least some of said software modules, parameters to be passed to said procedures pointed to.

27. The method of claim 19, wherein respective data definitions comprise the step of defining said one or more software modules of step (3), including pointers to procedures which will carry out a respective function, wherein most of said procedures pointed to correspond generally to one of a limited number of procedure types, and wherein at least some of said procedures pointed to also containing further pointers to procedures which do not correspond generally to any one of said limited number of procedure types, and, for at least some of said software modules, parameters to be passed to said procedures pointed to.

28. The method of claim 19, wherein one or more of said control parameters of step (2) comprise the step of including goals of said process controller.

29. A computer-based method for operating a substantially continuous process, comprising the steps of:

(1) operating the process with one or more sensors connected to sense conditions in the process, and one or more actuators connected to change conditions in the process; and

(2) controlling, using a process controller, one or more of said actuators

in accordance with signals received from one or more of said sensors

and in accordance with one or more control parameters,

(3) wherein at least one of said control parameters is redefined in accordance with output(s) which is selectively provided by at least one expert subprocedure which includes a knowledge base and inference structure relevant to the process, and

wherein said expert subprocedure fetches at least one value of a process variable from an historical database containing at least one time-stamped data regarding the process.

30. The method of claim 29, wherein said knowledge base and inference structure of step (3) comprise the step of defining a substantially real-time expert control procedure.

31. The method of claim 29, wherein said process controller of step (2) further comprises the step of operating substantially continuously in real time, and wherein said expert subprocedure of claim (3) comprises the step of not operating continuously in real time.

32. The method of claim 29, wherein said process controller of step (2) comprises the step of using real-time logic, and wherein said expert subprocedure of step (3) comprises the step of recurrently running as a batch process.

33. The method of claim 29, wherein said process controller uses analog logic for controlling.

34. A computer-based method for operating a substantially continuous process, comprising the steps of:

(1) operating the process with one or more sensors connected to sense conditions in the process, and one or more actuators connected to change conditions in the process; and

(2) controlling one or more of said actuators

in accordance with signals received from one or more of said sensors

and in accordance with one or more control parameters,

(3) wherein at least one of said control parameters is redefined in accordance with output(s) which is selectively provided by at least one expert subprocedure which includes a knowledge base and inference structure relevant to the process; and

(4) selectively presenting functional structures, to a user, for a new rule for said expert subprocedure and/or a functional structure corresponding to the user input from which a current version of said expert subprocedure was generated, and selectively compiling one or more user inputs from said functional structure into a new version of said expert subprocedure.

35. The method of claim 34, wherein said functional structure presented to the user in step (4) comprises the step of using a substantially natural language format which is readily understandable by a user who is technically skilled in a predetermined art but who is not necessarily competent in any computer language.

36. The method of claim 34, wherein only restricted portions of said functional structure of step (4) comprises the step of allowing for user-alterability.

37. The method of claim 34, wherein said functional structure of step (4) comprises the step of including user-alterable portions which appear differently to said user than do other portions of said functional structure.

38. The method of claim 34, wherein said step of presenting functional structures includes presenting standardized data interface definitions such that the user can specify data having one of plural pre-defined temporal characteristics.

39. The method of claim 34, wherein said knowledge base and inference structure of step (3) comprise the step of defining a substantially real-time expert control system.

40. A computer-based system for controlling a substantially continuous process, comprising:

(a) one or more sensors connected to sense conditions in the process, and one or more actuators connected to change conditions in the process;

(b) a process controller connected to directly receive sense data generated by at least one of said sensors, and connected to control one or more of said actuators in accordance with said sensor data and in accordance with respective control parameters;

(c) process supervisor means comprising one or more software modules, for communicating said control parameters to said process controller;

(d) at least one expert subprocedure means which uses a knowledge base and inference structure relevant to the process, and which is callable by said process supervisor means;

wherein said process supervisor means has a maximum iteration period significantly longer than the maximum iteration period of said process controller.

41. The system of claim 40, wherein said process supervisor means of element (c) uses means for cycling, and said process controller of element (b) runs substantially in real-time.

42. The system of claim 40, wherein said knowledge base and inference structure of element (d) define a substantially real-time expert control system.

43. The system of claim 40, wherein said process controller operates substantially continuously in real time, and said expert subprocedure means of element (d) does not operate continuously in real time.

44. The system of claim 40, wherein said process controller comprises real-time logic, and said expert subprocedure means of element (d) is recurrently run as a batch process.

45. The system of claim 40, wherein said controller is an analog controller.

46. The system of claim 40, wherein said one or more software modules of element (c) are defined by respective data definitions, including pointers to first means for carrying out a respective function, and, for at least some of said software modules, parameters to be passed to said first means pointed to.

47. The system of claim 40, wherein one or more of said control parameters of element (b) use goals of said process controller.

48. The system of claim 40, wherein said process controller of element (b) and said process supervisor means of element (c) comprise processes running on the same computer system.

49. The system of claim 40, wherein said process controller of element (b) and said process supervisor means of element (c) are both respective parts of the same software system.

50. A computer-based system for controlling a substantially continuous process, comprising:

(a) one or more sensors connected to sense conditions in the process, and one or more actuators connected to change conditions in the process;

(b) a process controller connected to receive sense data generated by at least one of said sensors, and connected to control one or more of said actuators in accordance with said sensor data and in accordance with respective control parameters;

(c) process supervisor means comprising one or more software modules, for communicating said control parameters to said process controller;

(d) at least one expert subprocedure means which uses a knowledge base and inference structure relevant to the process, and which is callable by said process supervisor means;

(e) an historical database containing at least one time-stamped data regarding the process;

wherein said process supervisor means has a maximum iteration period significantly longer than the maximum iteration period of said process controller.

51. The system of claim 50, wherein said knowledge base and inference structure of element (d) define a substantially real-time expert control system.

52. The system of claim 50, wherein said one or more software modules of element (c) are defined by respective data definitions, including pointers to first means for carrying out a respective function, and, for at least some of said software modules, parameters to be passed to said first means pointed to.

53. The system of claim 50, wherein said one or more software modules of element (c) are defined by respective data definitions, including pointers to first means for carrying out a respective function, wherein most of said first means pointed to correspond generally to one of a limited number of procedure types, and wherein at least some of said first means pointed to also containing further pointers to second means which do not correspond generally to any one of said limited number of procedure types, and, for at least some of said software modules, parameters to be passed to said first means pointed to.

54. The system of claim 50, wherein one or more of said control parameters of element (b) use goals of said process controller.

55. A computer-based system for controlling a substantially continuous process, comprising:

(a) one or more sensors connected to sense conditions in the process, and one or more actuators connected to change conditions in the process;

(b) a process controller connected to receive sense data generated by at least one of said sensors, and connected to control one or more of said actuators in accordance with said sensor data and in accordance with respective control parameters;

(c) process supervisor means comprising one or more software modules, connected to communicate said respective control parameters to said process controller;

(d) at least one expert subprocedure means which uses a knowledge base and inference structure relevant to the process, and which is callable by said process supervisor means;

(e) build-expert means which is configured to;

(1) upon command, selectively present to a user a functional structure for a new rule for said expert subprocedure means;

(2) upon command, selectively present to a user a functional structure corresponding to the user input from which a current version of said expert subprocedure means was generated;

(3) and selectively to compile one or more user inputs from said functional structure into a new version of said expert subprocedure means;

wherein said process supervisor means has a maximum iteration period significantly longer than the maximum iteration period of said process controller.

56. The system of claim 55, wherein said functional structure of element (1) presented to the user has a substantially natural language format which is readily understandable by a user who is technically skilled in a predetermined art but who is not necessarily competent in any computer language.

57. The system of claim 55, wherein only restricted portions of said functional structure of element (1) is user-alterable.

58. The system of claim 55, wherein said functional structure of element (1) comprises user-alterable portions which appear differently to said user than do other portions of said functional structure.

59. The system of claim 55, wherein said functional structure of element (1) uses standardized data interface definitions such that the user can specify data having one of plural pre-defined temporal characteristics.

60. The system of claim 55, wherein said knowledge base and inference structure of element (d) define a substantially real-time expert control system.

61. The system of claim 55, wherein said one or more software modules of element (c) are defined by respective data definitions, including pointers to first means for carrying out a respective function, and, for at least some of said software modules, parameters to be passed to said first means pointed to.

62. The system of claim 55, wherein one or more of said control parameters of element (b) use goals of said process controller.

63. A computer-based system for controlling a substantially continuous process, comprising:

(a) one or more sensors connected to sense conditions in the process, and one or more actuators connected to change conditions in the process;

(b) a process controller connected to receive sense data generated by at least one of said sensors, and connected to control one or more of said actuators in accordance with said sensor data and in accordance with respective control parameters;

(c) process supervisor means comprising one or more software modules, for communicating said control parameters to said process controller;

(d) at least one expert subprocedure means which uses a knowledge base and inference structure relevant to the process, and which is callable by said process supervisor means; and

(e) build-expert means which is configured to;

(1) upon command, selectively present to a user a functional structure for a new rule for said expert subprocedure means;

(2) upon command, selectively present to a user a functional structure corresponding to the user input from which a current version of said expert subprocedure means was generated;

(3) and selectively to compile one or more user inputs from said functional structure into a new version of said expert subprocedure means; and

(f) build-supervisor means which is configured to;

(4) upon command, selectively present to a user a functional structure for a new software module for said process supervisor means;

(5) upon command, present to a user a functional structure corresponding to a user input from which a current software module of said process supervisor means was generated;

(6) and selectively to load the user input from said functional structure to be used by said process supervisor means;

wherein said process supervisor means has a maximum iteration period significantly longer than the maximum iteration period of said process controller.

64. The system of claim 63, wherein said build-supervisor means of element (f) does not allow data corresponding to fresh user inputs to become actively accessed by said process supervisor means of element (c) until a validation run has been performed.

65. The system of claim 63, wherein said process supervisor means of element (c) uses means for cycling, and said process controller of element (b) runs substantially in real-time.

66. The system of claim 63, wherein said functional structure of element (1) presented to the user has a substantially natural language format which is readily understandable by a user who is technically skilled in a predetermined art but who is not necessarily competent in any computer language.

67. The system of claim 63, wherein only restricted portions of said functional structure of element (1) is user-alterable.

68. The system of claim 63, wherein said functional structure of element (1) comprises user-alterable portions which appear differently to said user than do other portions of said functional structure.

69. The system of claim 63, wherein said knowledge base and inference structure of element (d) define a substantially real-time expert control system.

70. The system of claim 63, wherein said process controller of element (b) operates substantially continuously in real time, and said expert subprocedure means of element (d) does not operate continuously in real time.

71. The system of claim 63, wherein said controller is an analog controller.

72. The system of claim 63, wherein said one or more software modules of element (c) are defined by respective data definitions, including pointers to first means for carrying out a respective function, and, for at least some of said software modules, parameters to be passed to said first means pointed to.

73. The system of claim 63, wherein said one or more software modules of element (c) are defined by respective data definitions, including pointers to first means for carrying out a respective function, wherein most of said means pointed to correspond generally to one of a limited number of procedure types, and wherein at least some of said first means pointed to also containing further pointers to second means which do not correspond generally to any one of said limited number of procedure types, and, for at least some of said software modules, parameters to be passed to said first means pointed to.

74. The system of claim 63, wherein one or more of said control parameters of element (b) use goals of said process controller.

75. The system of claim 63, wherein said process controller of element (b) and said process supervisor means of element (c) comprise processes running on the same computer system.

76. The system of claim 63, wherein said process controller of element (b) and said process supervisor means of element (c) are both respective parts of the same software system.

77. A computer-based method for operating a substantially continuous process, comprising the steps of:

(1) operating the process with one or more sensors connected to sense conditions in the process, and one or more actuators connected to change conditions in the process;

(2) controlling one or more of said actuators with a process controller in accordance with signals directly received from one or more of said sensors and in accordance with one or more control parameters;

(3) running a process supervisor procedure, comprising one or more software modules, connected to define one or more of said control parameters for said process controller; and

(4) calling by said process supervisor procedure an expert subprocedure which uses a knowledge base and inference structure relevant to the process for the steps of;

(i) defining one or more of said control parameters for said process controller;

or

(ii) controlling the defining of one or more of said control parameters by said process supervisor procedure.

78. The method of claim 77, wherein step (4) comprises a step of using two or more expert subprocedures, each having its own knowledge base.

79. The method of claim 77, wherein the step of using at least two expert subprocedures comprises the step of using a common inference structure for at least two of said expert subprocedures.

80. A computer-based method for operating a substantially continuous process, comprising the steps of:

(1) operating the process with one or more sensors connected to sense conditions in the process, and one or more actuators connected to change conditions in the process; and

(2) controlling, using a process controller, one or more of said actuators

in accordance with signals directly received from one or more of said sensors

and in accordance with one or more control parameters,

(3) wherein at least one of said control parameters is redefined in accordance with output(s) which is selectively provided by at least one expert subprocedure which uses a knowledge base and inference structure relevant to the process.

81. A computer-based method for operating a substantially continuous process, comprising the steps of:

(1) operating the process with one or more sensors connected to sense conditions in the process, and one or more actuators connected to change conditions in the process;

(2) controlling one or more of said actuators with a process controller in accordance with signals directly received from one or more of said sensors and in accordance with one or more control parameters; and

(3) running a process supervisor procedure, for selectively defining one or more of said control parameters for said process controller, said process supervisor procedure selectively using an expert subprocedure which uses a knowledge base and inference structure relevant to the process.