Wave reflection deformation sensing apparatus
A deformation sensing apparatus comprises a transmitter coupled to a propagation channel, and a receiver coupled to the same first end of the propagation channel. The propagation channel of the deformation is a transmission line, where a signal is transmitted by the transmitter and reflected signals are measured by the receiver responsive to the transmitted signals. A bend in the propagation channel results in a change in impedance of the transmission line at a location of the bend, resulting in a reflection of the signal from the location of the bend. The time delay of the reflected signals corresponds to the distance along the length of the channel where a bending of the propagation channel occurs. The amplitude of the reflected signal corresponds to a bend angle.
1. A method comprising:
transmitting a signal from a first end of a propagation channel along a length of the propagation channel;
detecting a first reflected signal corresponding to a first reflection of the signal along the length of the propagation channel;
responsive to a bend in the propagation channel, detecting a second reflected signal corresponding to a second reflection of the signal from a position of the bend along the length of the propagation channel; and
computing, based on amplitudes of the first reflected signal and the second reflected signal, a bend angle of the propagation channel.
2. The method of claim 1 , wherein the second reflection is caused by a change of impedance of the propagation channel at the location of the bend along the length.
3. The method of claim 1 , wherein amplitudes of the second reflected signal are each mapped to different bend angles of the propagation channel.
4. The method of claim 1 , wherein the amplitude of the second reflected signal is proportional to a change of impedance of the propagation channel.
5. The method of claim 1 , wherein a larger bend angle corresponds to the second reflected signal being stronger relative to a smaller bend angle.
6. The method of claim 1 , further comprising:
computing, based on a roundtrip time between transmission of the signal and a time when the second reflected signal is detected, a location of the bend in the propagation channel.
7. The method of claim 1 , wherein the propagation channel is used in wearable device including at least one of a glove, headset, or body of a user.
8. The method of claim 1 , wherein the propagation channel is incorporated into a glove wearable device that includes a plurality of propagation channels, each propagation channel corresponding to a finger.
9. The method of claim 8 , wherein detecting the first reflected signal and the second detected signal in a propagation channel corresponds to a single bend of a finger of a user.
10. The method of claim 8 , further comprising:
detecting a third reflected signal corresponding to a third reflection of the signal along the length of the propagation channel, wherein detecting the first reflected signal, the second detected signal, and the second reflected signal corresponds to a first bend of a finger of a user and detecting the third reflected signal corresponds to a second bend of the finger of the user along the propagation channel.
11. A non-transitory computer-readable storage medium including instructions that, when executed by a processor, cause the processor to:
transmit a signal from a first end of a propagation channel along a length of the propagation channel;
detect a first reflected signal corresponding to a first reflection of the signal along the length of the propagation channel;
detect, responsive to a bend in the propagation channel, a second reflected signal corresponding to a second reflection of the signal from a position of the bend along the length of the propagation channel; and
compute a bend angle of the propagation channel based on amplitudes of the first reflected signal and the second reflected signal.
12. The non-transitory computer-readable storage medium of claim 11 , wherein the second reflection is caused by a change of impedance of the propagation channel at the location of the bend along the length.
13. The non-transitory computer-readable storage medium of claim 11 , wherein the amplitude of the second reflected signal is proportional to the change of impedance of the propagation channel, and wherein amplitudes of the second reflected signal are each mapped to different bend angles of the propagation channel.
14. The non-transitory computer-readable storage medium of claim 11 , further comprising:
computing, based on a roundtrip time between transmission of the signal and a time when the second reflected signal is detected, a location of the bend in the propagation channel.
15. The non-transitory computer-readable storage medium of claim 11 , wherein the propagation channel is used in wearable device including at least one of a glove, headset, or body of a user.
16. The non-transitory computer-readable storage medium of claim 11 , wherein the propagation channel is incorporated into a glove wearable device that includes a plurality of propagation channels, each propagation channel corresponding to a finger.
17. The non-transitory computer-readable storage medium of claim 16 , wherein detecting the first reflected signal and the second detected signal in a propagation channel corresponds to a single bend of a finger of a user.
18. The non-transitory computer-readable storage medium of claim 16 , further comprising:
detecting a third reflected signal corresponding to a third reflection of the signal along the length of the propagation channel, wherein detecting the first reflected signal, the second detected signal, and the second reflected signal corresponds to a first bend of a finger of a user and detecting the third reflected signal corresponds to a second bend of the finger of the user along the propagation channel.