Systems and methods for transmitting data via a contactless cylindrical interface
Described herein are systems and methods that create a capacitive link based on a rotating cylinder capacitor. A cylindrical rotor rotates around a shaft and maintains an air gap between the cylindrical rotor and the shaft and to create one or more air gap capacitors. A first subsystem, comprising a light detection and ranging components, is coupled to the rotor. A second sub-subsystem, comprising data analysis functions, is coupled to the shaft. The first subsystem and the second subsystem are coupled via capacitive links created by the air gap capacitors. The communication signaling utilized on the capacitive links may be bi-directional and differential signaling. The first subsystem and the second subsystem may comprise a LIDAR light detection and ranging system. The second subsystem may power the first subsystem via inductive coupling.
1. A system comprising:
a cylindrical rotor comprising a cylindrical hole in a center of the cylindrical rotor;
a transmitter located on and coupled to the cylindrical rotor;
a shaft positioned inside the cylindrical hole;
a receiver located on and coupled to the shaft; and
a capacitive link that couples the transmitter to the receiver via an air gap capacitor positioned between the cylindrical rotor and the shaft.
2. The system of claim 1 further comprising:
a first ring attached to an inside surface of the cylindrical hole of the cylindrical rotor;
a second ring attached to an outer surface of the shaft; and
wherein, an air gap between the first ring and the second ring creates the air gap capacitor.
3. The system of claim 1 , wherein data is transmitted between the transmitter and the receiver via the capacitive link.
4. The system of claim 1 , wherein the cylindrical rotor rotates around the shaft.
5. A system comprising:
a cylindrical rotor comprising a cylindrical hole in a center of the cylindrical rotor;
one or more rotor rings that are attached to an inside surface of the cylindrical hole of the cylindrical rotor;
a first transceiver located on and coupled to the cylindrical rotor;
a shaft positioned inside the cylindrical hole in the center of the cylindrical rotor, wherein the cylindrical rotor rotates around the shaft;
one or more shaft rings that are attached on an outer surface of the shaft, wherein, each of the one or more rotor rings is paired with a corresponding one or more shaft rings;
a second transceiver located on and coupled to the shaft;
one or more air gap capacitors created by an air gap between each pair of rings; and
one or more capacitive links coupled between the first transceiver and the second transceiver based on the one or more air gap capacitors.
6. The system of claim 5 , wherein the one or more capacitive links create one or more corresponding separate connections between the first transceiver and the second transceiver.
7. The system of claim 5 , wherein the cylindrical rotor and the shaft comprises N corresponding pairs of rings that support N capacitive links.
8. The system of claim 5 , wherein a bi-directional differential signal is transmitted and received by the first transceiver and the second transceiver utilizing four capacitive links.
9. The system of claim 8 , wherein the capacitive links utilize a low voltage differential signaling (LVDS) protocol.
10. The system of claim 8 , wherein the capacitive links utilize Serializer/Deserializer (SERDES) interfaces.
11. The system of claim 8 , wherein the bi-directional differential signal is encoded and decoded with a Manchester code.
12. The system of claim 8 , wherein the bi-directional differential signal is processed with an error detecting code.
13. The system of claim 5 , wherein the shaft provides power to the cylindrical rotor via inductive coupling.
14. A method comprising:
rotating a cylindrical rotor around a shaft, wherein the cylindrical rotor comprises a first subsystem and the shaft comprises a second subsystem;
creating a set of capacitive links between the first subsystem and the second subsystem based on an air gap between a set of electrodes located on the cylindrical rotor and another corresponding set of electrodes located on the second subsystem; and
transmitting a first set of data from the first subsystem to the second subsystem and a second set of data from the second subsystem to the first subsystem via the set of capacitive links.
15. The method of claim 14 , wherein when a number of electrodes in each of the sets of electrodes is equal to N, the set of capacitive links comprises N communication links.
16. The method of claim 14 further comprising:
transmitting with bi-directional differential signaling over four capacitive links.
17. The method of claim 16 , further comprising:
encoding and decoding bi-directional differential signals with a Manchester code.
18. The method of claim 14 , further comprising:
powering the first subsystem by the second subsystem via inductive coupling.
19. The method of claim 14 , wherein the first subsystem and the second subsystem comprise a LIDAR system.
20. The method of claim 14 , wherein a tolerance of the air gap capacitor is less than 20%.