System and method for human body fall detection

• US 20060214806A1
• Filed: 03/22/2005
• Published: 09/28/2006
• Est. Priority Date: 03/22/2005
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: Borras, Rodrigo L., Gomez, Leticia, Clifford, Michelle A.
• Granted Patent: US 7,248,172 B2
• Time in Patent Office: Days
• US Class Current: 340/573.100
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/002 Monitoring the patient using a local or closed circuit, e.g. in a room or building A61B5/0017 takes precedence
• CPC Class Codes: A61B 5/0022 Monitoring a patient using a global network, e.g. telephone networks, internet
• 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
• CPC Class Codes: G16H 40/67 for remote operation
• CPC Class Codes: G16Z 99/00 Subject matter not provided for in other main groups of this subclass

Abstract

A system and method is provided for detection of a human body fall event. The fall detection system (100, 200) includes a monitoring unit (102, 202), including a plurality of accelerometers (106, 206), a processor (108, 208) and a wireless transmitter (110, 210). The plurality of accelerometers (106, 206) provide acceleration measurements to the processor (108, 208), the measurements describing the current acceleration of the person wearing the monitoring unit (102, 202) in all directions. The processor (108, 208) receives the acceleration measurements and compares the acceleration measurements to a value range to determine if the wearer is currently experiencing a fall event. The processor (108, 208) generates a signal in response to the detection of a fall event and the transmitter (110, 210) transmits the signal to a remote signal receiver (104, 204). The system and method can further detect non-movement in the wearer of the monitoring unit (102, 202) subsequent to the fall event to detect an unconscious wearer.

Claims

1. A system for determining if a body has fallen, the system comprising:

a local monitoring unit, the local monitoring unit comprising an accelerometer assembly attached to the body for generating signals representative of the body'"'"'s acceleration; and

a remote signal receiver configured to receive said signals and determine if said signals correspond to an acceleration pattern indicative of a fall.

2. A system for determining if a body has fallen as claimed in claim 1 wherein the accelerometer assembly includes a plurality of accelerometers, the plurality of accelerometers measuring acceleration of a body in a plurality of directions and producing a plurality of acceleration measurements.

3. A system for determining if a body has fallen as claimed in claim 2 wherein the local monitoring unit further includes a processor, the processor receiving the plurality of acceleration measurements from the plurality of accelerometers, comparing the plurality of acceleration measurements to a value range and generating a fall detection signal if the plurality of acceleration measurements are within the value range indicating a fall event has occurred.

4. A system for determining if a body has fallen as claimed in claim 3 wherein the local monitoring unit further comprises a wireless transmitter for transmitting the fall detection signal to the remote signal receiver.

5. A system for determining if a body has fallen as claimed in claim 4 wherein the remote signal receiver is one of a central monitoring site or a portable electronic device.

6. A system for determining if a body has fallen as claimed in claim 3 wherein the processor further determines if a non-linear fall is occurring by determining if the plurality of acceleration measurements has smoothness in a specified range.

7. A system for determining if a body has fallen as claimed in claim 3 wherein the plurality of accelerometers comprise a first accelerometer providing a first acceleration measurement x, a second accelerometer providing a second acceleration measurement y, and a third accelerometer providing a third acceleration measurement z, and wherein the processor determines if the plurality of acceleration measurements has smoothness within a specified range by determining if x²+y²+z² has a change less than a threshold delta value for a selected number of consecutive acceleration measurements.

8. A system for determining if a body has fallen as claimed in claim 3 wherein the plurality of accelerometers comprise a first accelerometer measuring acceleration in a X direction, a second accelerometer measuring acceleration in a Y direction, and a third accelerometer measuring acceleration in a Z direction, where X, Y and Z are perpendicular to each other.

9. A system for determining if a body has fallen as claimed in claim 3 wherein the processor further determines if a detected fall event was accompanied by external force by determining if a combination of the acceleration measurements exceeded a threshold value in a time period prior to the detected fall event.

10. A system for determining if a body is falling, the system comprising:

a local monitoring unit, the local monitoring unit comprising;

an accelerometer assembly attached to the body for generating signals representative of the body'"'"'s acceleration, the accelerometer assembly comprising at least one accelerometer measuring acceleration of a body in at least one direction, a processor for generating a signal representative of the body'"'"'s acceleration and a wireless transmitter for transmitting the signal generated in response to the detected fall event; and

a remote signal receiver comprising one of a central monitoring site or a portable electronic device, the remote signal receiver receiving the signal generated by the processor in response to the fall event.

11. A system for determining if a body is falling as claimed in claim 10 wherein the local monitoring unit includes a first accelerometer providing a first acceleration measurements x, a second accelerometer providing a second acceleration measurements y, and a third accelerometer providing a third acceleration measurements z.

12. A system for determining if a body is falling as claimed in claim 11 wherein the processor compares the first acceleration measurements x, the second acceleration measurements y, and the third acceleration measurements z to a value range, and determines if a fall event is occurring if the first acceleration measurements x, the second acceleration measurements y, and the third acceleration measurements z are each within the value range for a first selected number of measurement samples, the processor generating a signal in response to the detected fail event.

13. A system for determining if a body is falling as claimed in claim 11 further including a local signal receiving and transmitting unit for receiving the wireless signal generated by the local monitoring unit, and transmitting the signal to the remote signal receiver.

14. A method for determining if a body is falling, the method comprising:

measuring acceleration of a human body wearing a monitoring unit in a plurality of directions and producing a plurality of acceleration measurements;

comparing the plurality of acceleration measurements to a value range to determine if the plurality of acceleration measurements are within the value range indicating a fall event has occurred;

generating a signal in response to the fall event; and

transmitting the signal to a remote signal receiver.

15. A method for determining if a body is falling as claimed in claim 14 wherein the plurality acceleration measurement comprises a first acceleration measurement x, a second acceleration measurement y, and a third acceleration measurement z.

16. A method for determining if a body is falling as claimed in claim 14 wherein the plurality acceleration measurements are received from a plurality of accelerometers comprise micro machined accelerometers.

17. A method for determining if a body is falling as claimed in claim 14 wherein the plurality acceleration measurements are received from the plurality of accelerometers that comprise a first accelerometer measuring acceleration in a X direction, a second accelerometer measuring acceleration in a Y direction, and a third accelerometer measuring acceleration in a Z direction, where X, Y and Z are perpendicular to each other.

18. A method for determining if a body is falling as claimed in claim 17 further including the step of comparing the first acceleration measurements x, the second acceleration measurements y, and the third acceleration measurements z to a value range, wherein a fall is determined to be occurring if the first acceleration measurements x, the second acceleration measurements y, and the third acceleration measurements z are each within the value range for a first selected number of measurements.

19. A method for determining if a body is falling as claimed in claim 18 further including the step combining the first acceleration measurements x, the second acceleration measurements y, and the third acceleration measurements z into a combination of x²+y²+z² values and comparing the combination of x²+y²+z² values to a second value range, and determining if the combination of x²+y²+z² values has an amount of change less than a threshold delta value for a second selected number of measurements.

20. A method for determining if a body is falling as claimed in claim 19 further comprising determining if a detected fall was accompanied by external force by determining if a combination of the acceleration measurements exceeded a threshold value in a time period prior to the detected fall.