Measuring of a physiological parameter using a wearable sensor

Patent metadata

Field	Value
Publication number	US-2017347957-A1
Application number	US-201515536283-A
Country	US
Kind code	A1
Filing date	Dec 1, 2015
Priority date	Dec 18, 2014
Publication date	Dec 7, 2017
Grant date	—

Abstract

An apparatus comprises a sensor for measuring a physiological parameter of a subject, wherein the physiological parameter sensor is adapted to be worn by the subject; an actuator comprising an electro-active polymer material, EAP, portion for adjusting the position of the physiological parameter sensor relative to the subject; a feedback sensor for measuring movement of the physiological parameter sensor and/or the subject; a controller configured to process the measurements of the feedback sensor and to adjust the position of the actuator based on information from the feedback sensor.

First claim

1 . A wearable sensor apparatus, comprising:
a sensor for measuring a physiological parameter of a subject, wherein the sensor is adapted to be worn by the subject; an actuator comprising an electro-active polymer material portion for adjusting the position of the sensor relative to the subject; a feedback sensor for measuring movement of the physiological parameter sensor and/or the subject; and a controller configured to process a measurement of the feedback sensor and to control the actuator to adjust the position of the sensor based on the measurement of the feedback sensor, wherein the actuator is arranged to adjust the position of the physiological parameter sensor relative to the subject by exerting a force on the physioloigcal parameter sensor.

2 . The apparatus of claim 1 , wherein the feedback sensor is configured to measure a change in the contact force between the sensor and the subject.

3 . The apparatus of claim 2 further comprising a coupling member disposed on the sensor and arranged between the sensor and the subject in use.

4 . The apparatus of claim 1 , wherein the feedback sensor is configured to measure a change in a distance between the sensor and the subject.

5 . The apparatus of any preceding claim, wherein the sensor comprises:
a housing having walls which define an internal area; and a sensor element disposed inside the internal area of the housing, wherein the feedback sensor is configured to measure movement of the housing relative to the subject.

6 . The apparatus of claim 1 , wherein the sensor comprises the feedback sensor, and wherein the controller is configured to process a signal from the sensor and to adjust the position of the actuator based on the signal of the sensor.

7 . The apparatus of claim 6 , wherein the sensor comprises:
a housing having walls which define an internal area; a light source disposed in the internal area of the housing; and a light sensor disposed inside the internal area of the housing, wherein the controller is configured to process a signal of the light sensor and to adjust the position of the actuator based on the signal of the light sensor.

8 . The apparatus of claim 7 further comprising an external light sensor disposed outside of the housing, and wherein the controller is configured to process a signal of the external light sensor and to adjust the position of the actuator based the light signal of the external light sensor and the light sensor of the sensor.

9 . The apparatus of claim 7 , further comprising:
a signal generator adapted to:
generate a first electrical alternating signal, for use in sensing, having a first frequency;
generate a second electrical alternating signal, for use in actuation, having a second frequency wherein the second frequency is substantially the same as the first frequency; and
apply the first electrical signal to the sensor;

apply the second electrical signal to the actuator,
wherein the apparatus further comprises a detector for detecting a difference between the first electrical signal and the second electrical signal

10 . The apparatus of claim 1 , wherein the actuator further comprises a strain sensitive electrode portion disposed on the electroactive polymer portion, and the apparatus further comprises:
a first power or voltage source arranged to apply a first voltage to the electroactive polymer portion of the actuator; and a second power or voltage source arranged to apply a second voltage to the strain sensitive electrode portion of the actuator, wherein the controller is arranged to measure a change in resistivity of the strain sensitive electrode and to adjust the position of the actuator based on the measured change in resistivity.

11 . The apparatus of claim 1 , wherein the sensor comprises a housing and the actuator is arranged to exert a force on the housing in response to an actuation signal from the controller.

12 . A method for measuring a physiological parameter using the device of claim 1 , comprising:
(i) obtaining a signal using the feedback sensor; (ii) determining if the sensor has moved relative to the subject, based on the signal of the feedback sensor; (iii) if the sensor has moved relative to the subject, adjusting the position of the actuator according to the measured movement, wherein the actuator is adjusted to directly contact the sensor so that the actuator exerts a force on the physiological parameter sensor.

13 . The method of claim 12 , wherein step (ii) comprises comparing a measurement of contact pressure to a reference value for contact pressure.

14 . (canceled)

15 . The method of claim 12 , further comprising the steps of
(iv) applying a first alternating signal having a first frequency to the actuator; (v) applying a second alternating signal having a second frequency to the physiological parameter sensor, wherein the second frequency is the same as the first frequency; and (vi) comparing the first alternating signal and the second alternating signal to determine if the sensor has moved.

Assignees

• Koninklijke Philips Nv

Inventors

• Van Den Ende Daan Anton
• Haakma Reinder
• Johnson Mark Thomas
• Boekhorst Frederick Maria
• Kovacevic Milivojevic Milica
• Hakkens Franciscus Johannes Gerardus
• Hilgers Achim
• Hendriks Cornelis Petrus
• Ubachs Rene Leonardus Jacobus Marie
• Pelssers Eduard Gerard Marie

Classifications

• A61B5/6844

  Monitoring or controlling distance between sensor and tissue · CPC title

• A61B5/14551

  for measuring blood gases · CPC title

• A61B5/6824

  Arm or wrist · CPC title

• A61B5/7207

  of noise induced by motion artifacts · CPC title

• A61B5/02416

  using photoplethysmograph signals, e.g. generated by infrared radiation (A61B5/14552 takes precedence) · CPC title