All wheel drive robotic vehicle with steering brake

• US 10,259,498 B2
• Filed: 11/25/2015
• Issued: 04/16/2019
• Est. Priority Date: 12/02/2014
• Status: Active Grant

• Current Assignee: Husqvarna AB (HUSQVARNA)
• Original Assignee: Husqvarna AB (HUSQVARNA)
• Inventors: Jagenstedt, Patrik, Kallstrom, Fredrik, Bergenholm, Magnus, Svensson, Mats, Ohrlund, Magnus, Kamfors, Mattias
• Primary Examiner(s): Winner, Tony H
• Assistant Examiner(s): Arce, Marlon A
• Application Number:
  US15/532,591
• Publication Number:
  US 20180222528A1
• Time in Patent Office: 1,238 Days
• CPC Class Codes: A01D 34/008 for automated or remotely controlled operation
• CPC Class Codes: B60L 7/24 with additional mechanical or electromagnetic braking
• CPC Class Codes: B62D 12/00 Steering specially adapted for vehicles operating in tandem or having pivotally connected frames steering endless tracks or the like B62D11/00; steering specially adapted for trailers B62D13/00
• CPC Class Codes: B62D 53/02 comprising a uniaxle tractor unit and a uniaxle trailer unit see B60B11/00 - B60B11/08
• CPC Class Codes: B62D 63/02 Motor vehicles
• CPC Class Codes: B62D 63/04 Component parts or accessories
• CPC Class Codes: F16D 2121/20 using electromagnets
• CPC Class Codes: F16D 65/18 adapted for drawing members together , e.g. for disc brakes

Abstract

A robotic vehicle may include a first chassis platform including a first wheel assembly, a second chassis platform including a second wheel assembly where the first and second chassis platforms are spaced apart from each other, and a combination linkage operably coupling the first and second chassis platforms. The combination linkage may be operably coupled to the first chassis platform via a first link and is operably coupled to the second chassis platform via a second link. The combination linkage employs at least two different coupling features to operably couple the first and second chassis platforms. The at least two different coupling features include at least any two among a fixed attachment, an attachment that enables rotation about a turning axis, and an attachment that enables pivoting about a pivot axis that is substantially perpendicular to the turning axis.

Claims

1. A robotic vehicle comprising:

a first chassis platform comprising a first wheel assembly;

a second chassis platform comprising a second wheel assembly, the first and second chassis platforms being spaced apart from each other;

a linkage operably coupled to the first chassis platform and the second chassis platform, such that the linkage is fixed relative to the first chassis platform, and such that the second chassis platform is rotatable relative to the first chassis platform, wherein the second chassis platform comprises a turning axis; and

an electric brake disposed proximate to a turning shaft of the linkage, the electric brake being selectively applied by processing circuitry to resist turning of the second chassis platform about the turning axis and being selectively released to allow the second chassis platform to turn about the turning axis.

2. The robotic vehicle of claim 1 further comprising:

an angle sensor mounted proximate to the turning axis to monitor a turning angle of the second chassis platform relative to the first chassis platform, the angle sensor providing information indicative of the turning angle to the processing circuitry to enable the processing circuitry to employ a steering control based on the turning angle.

3. The robotic vehicle of claim 2, wherein the processing circuitry compares a current turn angle to a target turn angle;

wherein the processing circuitry applies the electric brake in response to the current turn angle satisfying a turn angle divergence threshold, and

wherein the processing circuitry releases the electric brake in response to the current turn angle failing to satisfy the turn angle divergence threshold.

4. The robotic vehicle of claim 1 further comprising:

a turning motor configured to interface with a turning shaft of the linkage to apply a rotational force to the turning shaft to turn the second chassis platform relative to the first chassis platform responsive to control from the processing circuitry,

wherein the processing circuitry is configured to release the electric brake prior to applying the rotational force and apply the electric brake whenever the rotational force is not applied.

5. The robotic vehicle of claim 1, wherein the electric brake is deenergized when applied and energized when released.

6. The robotic vehicle of claim 1, wherein the electric brake comprises:

a brake disc; and

an electromagnet configured to engage the brake disc when applied.

7. The robotic vehicle of claim 6, wherein the brake disc and electromagnet comprise an electropermanent magnet.

8. The robotic vehicle of claim 6, wherein the brake disc is a soft magnet.

9. The robotic vehicle of claim 6, wherein in response to the electromagnet being energized a magnetic field is reversed.

10. The robotic vehicle of claim 6, wherein the brake disk is physically connected to a guide rod allowing the brake disc to travel in response to the application of the electric brake, toward the electric brake, and in response to the release of the electric break, away from the electric brake.

11. The robotic vehicle of claim 10, wherein the guide rod penetrates the break disc but does not penetrate a plane in which a surface facing the electromagnet lies.

12. The robotic vehicle of claim 6, wherein the electromagnet is configured to rotate about the turning axis responsive to the second chassis platform turning about the turning axis and the electric brake is stationary relative to the turning axis, and

wherein the electromagnet aligns with different points of the brake disc at different points of rotations about the turning axis.

13. The robotic vehicle of claim 6, wherein the brake disc extends around the turning axis to at least a maximum turning angle of the second chassis platform.

14. The robotic vehicle of claim 6, wherein the brake disc extends at least 180 degrees around the turning axis.

15. The robotic vehicle of claim 6, wherein the brake disc is forced to a first position in response to the electric brake being applied and moves to a second position in response to the electric brake being released.

16. A robotic vehicle comprising:

a first chassis platform comprising a first wheel assembly;

a second chassis platform comprising a second wheel assembly, the first and second chassis platforms being spaced apart from each other;

a linkage operably coupled to the first chassis platform and the second chassis platform, such that the linkage is fixed relative to the first chassis platform and such that the second chassis platform is rotatable relative to the first chassis platform, wherein the second chassis platform comprises a turning axis; and

an electropermanent magnet electric brake comprising

a brake disc; and

an electromagnet configured to engage the brake disc when applied and disposed proximate to a turning shaft of the linkage, the electric brake being selectively applied by the processing circuitry to resist turning of the second chassis platform about the turning axis and being selectively released to allow the second chassis platform to turn about the turning axis.

17. The robotic vehicle of claim 16, wherein the electric brake is deenergized when applied and energized when released.

18. The robotic vehicle C Lar of claim 17, wherein in response to the electric brake being energized a magnetic field is reversed forcing the break disc away from the electric brake.

19. The robotic vehicle of claim 16, wherein the electric brake is configured to rotate about the turning axis responsive to the second chassis platform turning about the turning axis;

and wherein the electric brake is stationary relative to the turning axis.

20. The robotic vehicle of claim 16, wherein the brake disc extends around the turning axis to at least a maximum turning angle of the second chassis platform.