Devices and methods for a sensor platform of a vehicle

• US 10,502,574 B2
• Filed: 09/20/2016
• Issued: 12/10/2019
• Est. Priority Date: 09/20/2016
• Status: Active Grant

• Current Assignee: Waymo LLC (Alphabet Inc.)
• Original Assignee: Waymo LLC (Alphabet Inc.)
• Inventors: Robinson, Craig, Tisdale, John, LaForge, Seth, Karplus, Paul
• Primary Examiner(s): Shudy, Angelina
• Application Number:
  US15/271,140
• Publication Number:
  US 20180081361A1
• Time in Patent Office: 1,176 Days
• Field of Search: 701 23
• CPC Class Codes: B60W 2050/0083 Setting, resetting, calibration
• CPC Class Codes: B60W 40/114 Yaw movement
• CPC Class Codes: G01C 19/34 for indicating a direction in the horizontal plane, e.g. directional gyroscopes
• CPC Class Codes: G01C 21/18 Stabilised platforms, e.g. by gyroscope
• CPC Class Codes: G01C 21/20 Instruments for performing navigational calculations G01C21/24, G01C21/26 take precedence

Abstract

In one example, a vehicle includes a platform and a yaw sensor mounted on the platform. The yaw sensor provides an indication of a yaw rate of rotation of the yaw sensor. The vehicle also includes an actuator that rotates the platform. The vehicle also includes a controller coupled to the yaw sensor and the actuator. The controller receives the indication of the yaw rate from the yaw sensor. The controller also causes the actuator to rotate the platform (i) along a direction of rotation opposite to a direction of the rotation of the yaw sensor and (ii) at a rate of rotation based on the yaw rate of the yaw sensor. The controller also estimates a direction of motion of the vehicle in an environment of the vehicle based on at least the rate of rotation of the platform.

Claims

1. A vehicle comprising:

a platform;

a yaw sensor mounted on the platform, wherein the yaw sensor provides an indication of a yaw rate of rotation of the yaw sensor;

an actuator that rotates the platform;

an encoder coupled to the platform; and

a controller coupled to the yaw sensor and the actuator, wherein the controller;

receives the indication of the yaw rate from the yaw sensor;

causes the actuator to rotate the platform (i) along a direction of rotation opposite to a direction of the rotation of the yaw sensor and (ii) at a rate of rotation based on the yaw rate of the yaw sensor;

receives, from the encoder, measurements of the rotation of the platform caused by the actuator; and

estimates, based on at least the measurements of the rotation of the platform caused by the actuator, a direction of motion of the vehicle in an environment of the vehicle.

2. The vehicle of claim 1, further comprising:

a pitch sensor that provides output indicative of a pitch orientation of the vehicle about a pitch axis of the vehicle, wherein the controller estimates the direction of the vehicle based also on the output from the pitch sensor.

3. The vehicle of claim 2, further comprising:

a roll sensor that provides output indicative of a roll orientation of the vehicle about a roll axis of the vehicle, wherein estimating the direction of the vehicle based also on the output from the pitch sensor is in response to the roll orientation being at a threshold to a given roll orientation.

4. The vehicle of claim 1, further comprising:

a second actuator coupled to the platform to adjust a tilting angle of the platform, wherein the tilting angle corresponds to an offset to a yaw axis of the yaw sensor, the offset associated with a roll rotation or a pitch rotation of the vehicle.

5. The vehicle of claim 4, wherein the vehicle is an autonomous vehicle, wherein the controller receives an indication of an expected change to the direction of motion of the vehicle based on a predetermined navigation path of the vehicle, and wherein the controller causes the second actuator to adjust the tilting angle of the platform based on at least the received indication of the expected change to the direction of motion of the vehicle.

6. The vehicle of claim 4, further comprising a roll sensor that provides output indicative of a roll orientation of the vehicle about a roll axis, wherein the controller receives an indication of a change to the roll orientation of the vehicle from the roll sensor, and wherein the controller causes the second actuator to adjust the tilting angle of the platform based on at least the received indication of the change to the roll orientation of the vehicle.

7. The vehicle of claim 1, wherein the yaw sensor is a first yaw sensor, wherein the yaw rate is a first yaw rate, the vehicle further comprising:

a second yaw sensor that provides an indication of a second yaw rate of rotation of the second yaw sensor, wherein the first yaw sensor is mounted to the vehicle at a first tilting angle such that a first yaw axis of the first yaw sensor is at a first offset to a yaw axis of the vehicle, and wherein the second yaw sensor is mounted to the vehicle at a second tilting angle such that a second yaw axis of the second yaw sensor is at a second offset to the yaw axis of the vehicle.

8. The vehicle of claim 7, wherein the controller determines a direction of a change to the direction of motion of the vehicle,

wherein estimating the direction of motion of the vehicle based on at least the measurements of the rotation of the platform is based also on the determined direction corresponding to a direction of the first tilting angle, and

wherein the controller, based on the determined direction corresponding to a direction of the second tilting angle, estimates the direction of motion of the vehicle based on the second yaw rate of the second yaw sensor.

9. The vehicle of claim 1, wherein the encoder provides an indication of an orientation of the platform in response to the actuator causing the platform to rotate, wherein the controller determines a rate of rotation of the platform based on output from the encoder, and wherein the controller estimates the direction of motion of the vehicle based on the determined rate of rotation.

10. The vehicle of claim 1, further comprising:

data storage storing calibration data for the yaw sensor, wherein the calibration data is indicative of a mapping between given rates of rotation of the platform and previously measured yaw rates indicated by the yaw sensor, and wherein the controller estimates the direction of motion of the vehicle based also on the calibration data.

11. The vehicle of claim 10, further comprising an input interface, wherein the controller updates the calibration data in response to receiving a request for calibrating the yaw sensor via the input interface.

12. The vehicle of claim 10, further comprising a temperature sensor, wherein the calibration data includes an indication of a previously measured temperature indicated by the temperature sensor at a time of receipt of the previously measured yaw rates of the calibration data, and wherein the controller updates the calibration data based on at least the temperature sensor indicating a measured temperature that differs from the previously measured temperature by at least a threshold amount.

13. The vehicle of claim 10, wherein the controller updates the calibration data based on at least passage of a given amount of time from a time of a previous update to the calibration data.

14. The vehicle of claim 10, wherein the controller updates the calibration data in response to activation of the vehicle, and wherein activation of the vehicle causes the controller to receive power.

15. A method comprising:

receiving, from a yaw sensor mounted on a platform of a vehicle, an indication of a yaw rate of rotation of the yaw sensor;

rotating the platform according to (i) a direction of rotation opposite to a direction of the rotation of the yaw sensor and (ii) a rate of rotation based on the yaw rate of the yaw sensor;

receiving, from an encoder coupled to the platform, measurements of the rotation of the platform; and

estimating a direction of the vehicle in an environment based on at least the measurements of the rotation of the platform received from the encoder.

16. The method of claim 15, further comprising:

determining that the vehicle is tilting about a roll axis of the vehicle or a pitch axis of the vehicle, wherein the tilting of the vehicle causes a tilt offset to a yaw axis of the yaw sensor; and

responsively actuating the platform to reduce the tilt offset.

17. A method comprising:

obtaining sensor data collected using a sensor mounted on a platform of a vehicle, wherein the sensor data includes an indication of a rate of change to a direction of the sensor about a reference axis of the sensor;

rotating the platform such that (i) a direction of the rotation is opposite to a direction of the change to the direction of the sensor and (ii) a rate of the rotation is based on the rate of change to the direction of the sensor;

receiving, from an encoder coupled to the platform, measurements of the rotation of the platform; and

based on at least the measurements of the rotation of the platform received from the encoder, estimating a direction of the vehicle in an environment of the vehicle.

18. The method of claim 17, further comprising:

accessing stored calibration data associated with the sensor, wherein the stored calibration data maps given rates of rotation of the platform to previously measured rates of change to the direction of the sensor, and wherein estimating the direction of the vehicle is also based on the stored calibration data.

19. The method of claim 17, further comprising:

enabling a calibration mode of the vehicle, wherein estimating the direction of the vehicle is based also on the vehicle having an enabled operation mode other than the calibration mode;

based on at least the calibration mode being enabled, rotating the platform according to a sequence of given rates of rotation;

for the given rates of rotation in the sequence, obtaining respective measurements indicated by the sensor; and

generating calibration data that maps the given rates of rotation of the platform to the respective measured rates indicated by the sensor.

20. The method of claim 19, further comprising:

based on the calibration mode being enabled, causing a conditioning device of the vehicle to adjust a temperature of the sensor to a given temperature; and

associating the generated calibration data with the given temperature.