Robot charger docking control

Patent metadata

Field	Value
Publication number	US-10761539-B2
Application number	US-201715821650-A
Country	US
Kind code	B2
Filing date	Nov 22, 2017
Priority date	Nov 22, 2017
Publication date	Sep 1, 2020
Grant date	Sep 1, 2020

Abstract

A method and system for docking a robot with a charger docking station, including receiving an initial pose and receiving a mating pose associated with the robot charger docking station, performing a first navigation from a location to the initial pose, and performing a second navigation of the robot from the initial pose to the mating pose. The second navigation may proceed substantially along an arc path from the initial pose to the mating pose, thereby, upon arriving at the mating pose, an electrical charging port of the robot mates with an electrical charging assembly. The arc path may be associated with a section of a unique circle having a radius and a center equidistant from the initial pose and the mating pose. Controlling for error may include a proportional control and/or weighted control or switching between the controls to maintain an error below a threshold.

First claim

We claim:

1. A method for navigating a robot for docking with a robot charger docking station, comprising:
receiving an initial pose associated with a robot charger docking station;
receiving a mating pose associated with the robot charger docking station;
performing a first navigation of a robot from a location to the initial pose; and
performing a second navigation of the robot from the initial pose to the mating pose,
wherein the second navigation proceeds substantially along an arc path from the initial pose to the mating pose, thereby causing the electrical charging port of the robot to mate with an electrical charging assembly of the robot charger docking station; and
wherein the arc path from the initial pose to the mating pose comprises a section of a unique circle having radius r and center X C , Y C equidistant from the first location X R , Y R associated with the initial pose and a second location X D , Y D associated with the mating pose, and wherein a tangent to the unique circle at the second location X D , Y D is perpendicular to the robot charger docking station;
wherein an instantaneous linear velocity x′ R and an instantaneous angular velocity θ′ R of the robot, at a pose along the arc path, are maintained in substantially constant relation with radius r:

θ
R
′

=

x
R
′

r

(
7
)

and wherein controlling a rotational error of the robot comprises issuing a proportional control according to:
θ′ R =kΦ   (8)

where k is a proportional control constant and Φ is a rotational error, and/or a weighted control according to

θ
R
′

=

α
⁡

(

k
⁢

⁢
ϕ

)

+

β
⁢

⁢

(

x
R
′

r

)

(
9
)

where α and β are weighting parameters.

2. The method of claim 1 , wherein the weighting parameters α and β may be adjusted in nonlinear relation as a function of the distance to the charging station.

3. The method of claim 1 , wherein controlling the robot comprises:
closing the rotational error according to equation (8) until the error gets below a threshold;
setting linear velocity x′ R to a fixed value; and
controlling the robot according to equation (7) constantly updating radius r and rotational error Φ;
wherein when the threshold is exceeded, switching the control to equation (8) until the error returns to below the threshold.

4. A mobile robot configured to navigate from a location to and dock with a robot charger docking station for re-charging, the robot comprising:
a wheeled mobile base having an electrical charging port and a processor, wherein the processor is configured to:
obtain an initial pose associated with the robot charger docking station;
obtain a mating pose associated with the robot charger docking station;
navigate the wheeled mobile base from the location to the initial pose;

navigate the wheeled mobile base from the initial pose to the mating pose, wherein the wheeled mobile base proceeds substantially along an arc path from the initial pose to the mating pose, thereby causing the electrical charging port of the wheeled base to mate with an electrical charging assembly of the robot charger docking station; and
wherein the arc path from the initial pose to the mating pose comprises a section of a unique circle having radius r and center X C , Y C equidistant from the first location X R , Y R associated with the initial pose and a second location X D , Y D associated with the mating pose, and wherein a tangent to the unique circle at the second location X D , Y D is perpendicular to the robot charger docking station;
wherein an instantaneous linear velocity x′ R and an instantaneous angular velocity θ′ R of the robot, at a pose along the arc path, are maintained in substantially constant relation with radius r:

θ
R
′

=

x
R
′

r

(
7
)

and wherein controlling a rotational error of the robot comprises issuing a proportional control according to:
θ′ R =kΦ   (8)

where k is a proportional control constant and Φ is a rotational error, and/or a weighted control according to

θ
R
′

=

α
⁡

(

k
⁢

⁢
ϕ

)

+

β
⁢

Assignees

• Locus Robotics Corp

Inventors

• Moore Thomas
• Powers Bradley
• Kwa Hian Kai

Classifications

• Y02T10/7072

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• Y02T10/70

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• G05D2101/10

  using artificial intelligence [AI] techniques · CPC title

• G05D2107/70

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• G05D1/247

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