FALL DETECTION SYSTEM

• US 20100121226A1
• Filed: 04/15/2008
• Published: 05/13/2010
• Est. Priority Date: 04/19/2007
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Ten Kate, Warner, Schonenberg, Rudie Bernardus Maria, Chen, Ningjiang, Kim, Sheng, Schlumbohm, Stephan, Flinsenberg, Ingrid Christina Maria
• Granted Patent: US 8,408,041 B2
• Time in Patent Office: Days
• US Class Current: 600/595
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/1117 Fall detection
• CPC Class Codes: G08B 21/0446 worn on the body to detect changes of posture, e.g. a fall, inclination, acceleration, gait

Abstract

The invention relates to a fall detection system, for detecting human fall incidents. The detection system comprises a sensor module to be worn by a user, for collecting motion data of his body, for instance acceleration data; first evaluation logic for identifying a potential fall incident on the basis of an impact observed in the acceleration data; and second evaluation logic for verifying that the sensor module is actually worn by the user, at least around the time of said impact, to prevent the system from raising an alarm if only the sensor module has fallen. The second evaluation logic may comprise free fall detection means for evaluating the acceleration data on characteristics which are typical for a free falling object, such as one or more full rotation and/or a free falling phase, during which the magnitude of the acceleration data is relatively stable and small. Additionally or alternatively the second evaluation logic may comprise body proximity detection means for detecting whether the sensor module is in close proximity to the human body.

Claims

1. Fall detection system, comprising:

a sensor module to be worn by a user, for collecting motion data based on the user'"'"'s motion;

first evaluation logic for identifying a potential fall incident on a basis of an impact observed in said motion data; and

second evaluation logic for verifying that the sensor module is actually worn by the user, at least around the time of said impact, the second evaluation logic comprising;

free fall detection means for evaluating the motion data on characteristics which are typical for a free falling object; and

/or

body proximity detection means for detecting whether the sensor module is in close proximity to the user'"'"'s body.

2. Fall detection system according to claim 1, wherein the free fall detection means are arranged to identify the absence or presence of a free fall phase, wherein during a predetermined time interval preceding the impact, a magnitude of acceleration data is substantially stable and smaller than a preset threshold value.

3. Fall detection system according to claim 2, wherein the preset threshold value is selected as a fraction of the magnitude of the acceleration at the onset of the potential fall incident.

4. Fall detection system according to claim 1, wherein the free fall detection means are arranged to identify an absence or presence of at least one full rotation.

5. Fall detection system according to claim 1, wherein the free fall detection means are arranged to identify an absence or presence of at least one full rotation on a basis of linear acceleration data.

6. Fall detection system according to claim 1, wherein the free fall detection means comprise an angular sensor, for measuring angular motions, in particular angular accelerations.

7. Fall detection system according to claim 1, wherein the body proximity detection means comprise an electrical field sensor, arranged to measure a distortion of an electrical field, when in close proximity to a user'"'"'s body.

8. Fall detection system according to claim 1, wherein the body proximity detection means comprise at least a sender and a receiver, one being securely attached to the user'"'"'s body, the other being accommodated in the sensor module, wherein said sender and receiver can only communicate with each other when at a mutual distance which corresponds to or is less than approximately half the user'"'"'s height.

9. Fall detection system according to claim 1, wherein the body proximity detection means comprise a sender and a receiver, which are arranged to communicate to each other through body-coupled communication, wherein the user'"'"'s body is used for data transmission.

10. Fall detection system according to claim 1, arranged to detect relative changes in orientation of the sensor module.

11. Fall detection system according to claim 10, wherein the evaluation logic comprises averaging means, for averaging acceleration data obtained from the sensor module, a memory for storing the averaged output signals for the averaging means, and a comparator for comparing the direction of one averaged output signal with that of an earlier, stored version.

12. Fall detection system according to claim 10, wherein the averaging means comprise a low-pass filter, an integrator and/or autocorrelation computation means.

13. Fall detection system according to claim 10, wherein a time interval over which the averaging means average the acceleration data is adjustable, in accordance with a detection state of the fall detection system, i.e. whether or not a potential fall incident has been detected.

14. Fall detection system according to claim 13, wherein the time interval is adjusted to be relatively long, as long as no potential fall incident has been detected.

15. Fall detection system according to claim 10, wherein the comparator comprises means to compute the vector out product of two averaged output signals, and means to compute whether the magnitude of said vector out product exceeds a certain, predetermined threshold value.