Systems and methods for extending the battery life of a wireless sensor in a building control system

Patent metadata

Field	Value
Publication number	US-10042340-B2
Application number	US-201614989740-A
Country	US
Kind code	B2
Filing date	Jan 6, 2016
Priority date	Jan 6, 2016
Publication date	Aug 7, 2018
Grant date	Aug 7, 2018

Abstract

A building control system includes a wireless measurement device and a controller. The wireless measurement device measures a plurality of values of an environmental variable and uses the plurality of measured values to predict one or more future values of the environmental variable. The wireless device periodically transmits, at a transmission interval, a message that includes a current value of the environmental variable and the one or more predicted values of the environmental variable. The controller receives the message from the wireless device and parses the message to extract the current value and the one or more predicted future values of the environmental variable. The controller periodically and sequentially applies, at a controller update interval shorter than the transmission interval, each of the extracted values as an input to a control algorithm that operates to control the environmental variable.

First claim

What is claimed is:

1. A building control system comprising:
a wireless measurement device comprising:
a sensor that measures a plurality of values of an environmental variable at a location of the wireless measurement device;
a predictor that uses the plurality of values of the environmental variable to predict one or more future values of the environmental variable; and
a first wireless radio that periodically transmits, at a transmission interval, a message comprising a current value of the environmental variable and the one or more predicted future values of the environmental variable;
wherein the wireless measurement device compares an actual measured value of the environmental variable with a previously-predicted value of the environmental variable and transmits the message to the controller in response to a determination that the actual measured value differs from the previously-predicted value; and
a controller comprising:
a second wireless radio that receives the message from the wireless measurement device;
a message parser that parses the message to extract the current value and the one or more predicted future values of the environmental variable; and
a feedback controller that periodically and sequentially applies, at a controller update interval shorter than the transmission interval, each of the current value and the one or more predicted future values as an input to a control algorithm that operates to control the environmental variable.

2. The building control system of claim 1 , wherein the wireless measurement device periodically measures the environmental variable at a measurement interval shorter than the transmission interval.

3. The building control system of claim 1 , wherein the wireless measurement device predicts a future value of the environmental variable for each controller update interval within the transmission interval.

4. The building control system of claim 1 , wherein the wireless measurement device:
compares the current measured value of the environmental variable with a previous measured value of the environmental variable;
determines a rate of change of the environmental variable between the current and previous measured value; and
transmits the message to the controller in response to a determination that the rate of change exceeds a threshold.

5. The building control system of claim 1 , wherein the wireless measurement device:
compares an actual measured value of the environmental variable at a particular time with a previously-predicted value of the environmental variable for the particular time;
determines whether a difference between the actual measured value and the previously-predicted value exceeds a threshold; and
transmits the message to the controller in response to a determination that the difference between the actual measured value and the previously-predicted value exceeds the threshold.

6. The building control system of claim 1 , wherein the wireless measurement device:
compares an actual measured value of the environmental variable with at least one of a previously-predicted value of the environmental variable and a previously-measured value of the environmental variable; and
redefines a prediction algorithm used by the predictor in response to at least one of:
a difference between the actual measured value of the environmental variable and the previously-predicted value of the environmental variable exceeding a threshold; and
a rate of change of the environmental variable exceeding a threshold.

7. A method for controlling an environmental variable in a building control system, the method comprising:
measuring a plurality of values of the environmental variable using a sensor of a wireless measurement device;
predicting, by the wireless measurement device, one or more future values of the environmental variable based on the plurality of values;
periodically transmitting, at a transmission interval, a message from the wireless measurement device to a controller, the message comprising a current value of the environmental variable and the one or more predicted future values of the environmental variable;
comparing an actual measured value of the environmental variable at a particular time with a previously-predicted value of the environmental variable for the particular time;
determining whether a difference between the actual measured value and the previously-predicted value exceeds a threshold;
transmitting the message to the controller in response to a determination that the difference between the actual measured value and the previously-predicted value exceeds the threshold;
parsing the message at the controller to extract the current value and the one or more predicted future values of the environmental variable; and
periodically and sequentially applying, at a controller update interval shorter than the transmission interval, each of the current value and the one or more predicted future values as an input to a control algorithm that operates to control the environmental variable.

8. The method of claim 7 , wherein measuring the plurality of values of the environmental variable comprises periodically measuring the environmental variable at a measurement interval shorter than the transmission interval.

9. The method of claim 7 , further comprising:
comparing the current measured value of the environmental variable with a previous measured value of the environmental variable;
determining a rate of change of the environmental variable between the current and previous measured value; and
transmitting the message to the controller in response to a determination that the rate of change exceeds a threshold.

10. The method of claim 7 , wherein predicting the environmental variable comprises predicting a future value of the environmental variable for each controller update interval within the transmission interval.

11. The method of claim 7 , further comprising:
comparing an actual measured value of the environmental variable with a previously-predicted value of the environmental variable; and
adjusting the transmission interval based on one of:
a difference between the actual measured value of the environmental variable and the previously-predicted value of the environmental variable; and
a rate of change of the environmental variable.

12. The method of claim 7 , further comprising:
comparing an actual measured value of the environmental variable with the previously-predicted value of the environmental variable; and
redefining a prediction algorithm used by the wireless measurement device based on one of:
a difference between the actual measured value of the environmental variable and the previously-predicted value of the environmental variable; and
a rate of change of the value of the environmental variable.

13. A wireless measurement device comprising:
a sensor that measures a plurality of values of an environmental variable at a location of the wireless measurement device;
a predictor that uses the plurality of values of the environmental variable to predict one or more future values of the environmental variable;
a first wireless radio that periodically transmits to a controller, at a transmission interval, a message comprising a current value of the environmental variable and the one or more predicted future values of the environmental variable;
a transmission timer that controls the transmission interval, wherein the controller is configured to control the environmental variable using the message and a control algorithm; and
a comparator that compares an actual measured value of the environmental variable with a previously-predicted valu

Assignees

• Johnson Controls Tech Co

Inventors

• Hofschulz Heidi A
• Turney Robert D
• Gamroth Timothy C
• Ellis Matthew J

Classifications

• G01D9/32

  there being a common recording element for two or more variables · CPC title

• H04W52/0216

  using a pre-established activity schedule, e.g. traffic indication frame · CPC title

• H04W4/70

  Services for machine-to-machine communication [M2M] or machine type communication [MTC] · CPC title

• G01D11/00

  Component parts of measuring arrangements not specially adapted for a specific variable (G01D13/00, G01D15/00 take precedence) · CPC title

• H04W52/0209 Primary

  in terminal devices · CPC title