US4639853A — Time-discrete adaptive switching on-off controller

Claim 1

Independent Claim 238 words

An apparatus for a discrete-time adaptive on-off switching control of a continuous-time process by means of a binary switching actuator producing two levels of actuating switching signals to on-off control said process, said apparatus using for a determination of an on-off actuating signal a prediction of a process output sequence over several future sampling intervals as a response to a possible process input sequence that is applied to a discrete-time linear process model, and estimating and updating in every sampling interval parameters of a process model by means of a parameter estimation means in order to adapt the parameters to the process to be controlled, even when the process behavior changes, said apparatus having a device to input and change a setpoint as well as a measuring device for a periodic measurement of the process output, characterized in that it comprises: two alternatively working first and second control means, said first control means being active in a stationary phase of the process and said second control means being active in a start-up phase of the process or after setpoint changes, each of said control means operating differently to produce control signals for said actuator, and switching means which activates one or the other of said control means in dependence of the result of a measurement of the process output and a current setpoint, said actuator being controlled by the control means which is activated by the switching means.

Claim 2

Independent Claim 238 words

An apparatus for a discrete-time adaptive on-off switching control of a continuous-time process by means of a binary switching actuator producing two levels of actuating switching signals to on-off control said process, said apparatus using for a determination of an on-off actuating signal a prediction of a process output sequence over several future sampling intervals as a response to a possible process input sequence that is applied to a discrete-time linear process model, and estimating and updating in every sampling interval parameters of a process model by means of a parameter estimation means in order to adapt the parameters to the process to be controlled, even when the process behavior changes, said apparatus having a device to input and change a setpoint as well as a measuring device for a periodic measurement of the process output, characterized in that it comprises: two alternatively working first and second control means, said first control means being active in a stationary phase of the process and said second control means being active in a start-up phase of the process or after setpoint changes, each of said control means operating differently to produce control signals for said actuator, and switching means which activates one or the other of said control means in dependence of the result of a measurement of the process output and a current setpoint, said actuator being controlled by the control means which is activated by the switching means.

Claim 3

Dependent Claim 45 words

An apparatus as claimed in claim 1, wherein said switching means activates the second control means if the process has to be started or has to follow a setpoint change and activates the first control means if the process is run in the stationary phase.

Claim 4

Dependent Claim 27 words

An apparatus as claimed in claim 1, wherein said two control means are provided with informtion about the process by means of a common parameter estimation means.

Claim 5

Dependent Claim 63 words

An apparatus as claimed in claim 1, wherein said first control means predicts all possible 2 R future process output sequences, wherein the prediction of the process output sequence on the basis of a certain process input sequence is made by reusing the prediction of a portion of the process output sequence made on the basis of at least another process input sequence.

Claim 6

Dependent Claim 33 words

An apparatus as claimed in claim 1, wherein said first control means decouples a prediction time from a sampling time by dividing each discrete-time prediction step into a prefixed number of sampling intervals.

Claim 7

Dependent Claim 39 words

An apparatus as claimed in claim 1, wherein a determination of an evaluation parameter for each predicted process output and a resulting selection of the actuating signal for a next sampling interval is carried out together with the prediction.

Claim 8

Dependent Claim 54 words

An apparatus as claimed in claim 1, wherein the second control means predicts an extremal point of a process input sequence within which only one switching of an actuating signal occurs, the switching occurring after a first sampling interval of said process input sequence within which only one switching of an actuating signal occurs.

Claim 9

Dependent Claim 61 words

An apparatus as claimed in claim 7, wherein the actuating signal for a next sampling interval is taken from the said process input sequence within which only one switching of an actuating signal occurs, if a system deviation in the extremal point of the future process output sequence is of such a nature that no overshooting of the process output occurs.

Claim 10

Dependent Claim 59 words

An apparatus as claimed in claim 7, wherein, when process output overshooting occurs, the actuating signal is taken for the next sampling interval that results from a switching of the actuating signal to its counteracting level that is for the first sampling interval of the said process input sequence within which only one switching of an actuating signal occurs.

Claim 11

Dependent Claim 41 words

An apparatus as claimed in claim 7, wherein a prediction time is determined in such a manner that a time available within one sampling interval is used entirely for determining the actuating signal to be applied in the next sampling interval.

Claim 12

Dependent Claim 48 words

An apparatus as claimed in claim 1, further comprising a limit supervisory control means for turning off the active control means to switch the actuating signal of the process off or on if the process output exceeds the preselected upper or lower limit of the process output, respectively.

Claim 13

Dependent Claim 45 words

An apparatus as claimed in claim 1, further comprising manually operable limit supervisory control means for controlling the process by means of the actuator in such a way that the parameter estimation means yields a process model which can be used for later adaptive control.

Claim 14

Dependent Claim 17 words

An arrangement as claimed in claim 1, wherein the actuator is used synchronously with the measuring device.

Claim 15

Independent Claim 175 words

An apparatus used in the transient phase of a process to be controlled comprising: means for generating a process input sequence within which only one switching of an actuating signal occurs, the switching occurring after a first sampling interval of the process input sequence, means for predicting a process output sequence over a number of future sampling intervals as a response to the process input sequence generated that is applied to a discrete-time linear process model, and further predicting the extremal point of the process output sequence, and means for selecting an actuating signal for the next sampling interval from the process input sequence generated, if a system deviation in the extremal point of the future process output sequence is of such a nature that no overshooting of the process output occurs, and for selecting, where overshooting of a process occurs, an actuating signal for the next sampling interval that results from a switching of such actuating signal to its counteracting level that is for the first sampling interval of the process input sequence generated.

Claim 16

Independent Claim 175 words

An apparatus used in the transient phase of a process to be controlled comprising: means for generating a process input sequence within which only one switching of an actuating signal occurs, the switching occurring after a first sampling interval of the process input sequence, means for predicting a process output sequence over a number of future sampling intervals as a response to the process input sequence generated that is applied to a discrete-time linear process model, and further predicting the extremal point of the process output sequence, and means for selecting an actuating signal for the next sampling interval from the process input sequence generated, if a system deviation in the extremal point of the future process output sequence is of such a nature that no overshooting of the process output occurs, and for selecting, where overshooting of a process occurs, an actuating signal for the next sampling interval that results from a switching of such actuating signal to its counteracting level that is for the first sampling interval of the process input sequence generated.

Claim 17

Independent Claim 257 words

A method of operating an apparatus for a discrete-time adaptive on-off switching control of a continuous-time process by means of a binary switching actuator producing two levels of actuating switching signals to on-off control said process, said apparatus using for a determination of an on-off actuating signal a prediction of a process output sequence over several future sampling intervals as a response to a possible process input sequence that is applied to a discrete-time linear process model, and estimating and updating in every sampling interval parameters of a process model by means of a parameter estimation means in order to adapt the parameters to the process to be controlled, even when the process behavior changes, said apparatus having a device to input and change a setpoint as well as a measuring device for a periodic measurement of the process output, said method comprising: predicting in a stationary phase all possible 2 R future process output sequences and predicting in a transient phase an extremal point of one future process output sequence which is caused by a process input sequence within which only one switching of an actuating signal occurs, the switching occurring after a first sampling interval of said process input sequence, within which only one switching of an actuating signal occurs, selecting one or the other prediction in dependence of the result of the measurement of the process output and a current input setpoint, and actuating the actuator in a next sampling interval based on a switching level produced from said one or the other prediction.

Claim 18

Independent Claim 257 words

A method of operating an apparatus for a discrete-time adaptive on-off switching control of a continuous-time process by means of a binary switching actuator producing two levels of actuating switching signals to on-off control said process, said apparatus using for a determination of an on-off actuating signal a prediction of a process output sequence over several future sampling intervals as a response to a possible process input sequence that is applied to a discrete-time linear process model, and estimating and updating in every sampling interval parameters of a process model by means of a parameter estimation means in order to adapt the parameters to the process to be controlled, even when the process behavior changes, said apparatus having a device to input and change a setpoint as well as a measuring device for a periodic measurement of the process output, said method comprising: predicting in a stationary phase all possible 2 R future process output sequences and predicting in a transient phase an extremal point of one future process output sequence which is caused by a process input sequence within which only one switching of an actuating signal occurs, the switching occurring after a first sampling interval of said process input sequence, within which only one switching of an actuating signal occurs, selecting one or the other prediction in dependence of the result of the measurement of the process output and a current input setpoint, and actuating the actuator in a next sampling interval based on a switching level produced from said one or the other prediction.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1990-01-26	1990-07-28	1991-01-27	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1994-01-26	1994-07-28	1995-01-27	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1998-01-26	1998-07-28	1999-01-27	$7700.00	Window Closed / Lapsed

Time-discrete adaptive switching on-off controller

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