APPARATUS AND METHODS FOR CONTROL OF A VEHICLE

• US 20110213522A1
• Filed: 02/28/2011
• Published: 09/01/2011
• Est. Priority Date: 02/26/2010
• Status: Active Grant

• Current Assignee: Segway Incorporated (Ninebot Ltd.)
• Original Assignee: Segway Incorporated (Ninebot Ltd.)
• Inventors: Hussey, Patrick A., Shaffer, Benjamin C., Heinzmann, John David, Stevens, Jon M.
• Granted Patent: US 8,688,303 B2
• Time in Patent Office: Days
• US Class Current: 701/22
• CPC Class Codes: A61G 5/043 Mid wheel drive
• CPC Class Codes: A61G 5/1016 on the rim
• CPC Class Codes: B60L 15/20 for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
• CPC Class Codes: B60L 15/2009 for braking
• CPC Class Codes: B60L 2200/16 Single-axle vehicles
• CPC Class Codes: B60L 2200/24 Personal mobility vehicles
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 2240/16 longitudinal
• CPC Class Codes: B60L 2240/20 angular
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/429 Current
• CPC Class Codes: B60L 2240/461 Speed
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 2260/34 Stabilising upright position of vehicles, e.g. of single axle vehicles
• CPC Class Codes: B60L 2260/44 by parameter estimation
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 7/26 Controlling the braking effect
• CPC Class Codes: B62J 17/08 Hoods protecting the rider
• CPC Class Codes: B62K 11/007 : Automatic balancing machines with single main ground engaging wheel or coaxial wheels supporting a rider
• CPC Class Codes: G01R 31/3648 : comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G05D 1/0891 : specially adapted for land vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility

Abstract

Method for controlling a vehicle that includes a support, at least one wheel, a platform coupled to the at least one wheel, a coupling structure having a support portion coupled to the support and a platform portion coupled to the platform that allows the support portion to move or slide fore and aft with respect to the platform portion, an actuator coupled to the coupling structure to control the position of the support portion relative to the platform portion, a drive coupled to the at least one wheel to deliver power to the at least one wheel to propel the vehicle and maintain the platform level, and a controller coupled to the drive to control the drive and coupled to the actuator to control the actuator.

Claims

1. A method for controlling speed of a vehicle, the vehicle comprising a support, at least one wheel, a platform coupled to the at least one wheel, a coupling structure having a support portion coupled to the support and a platform portion coupled to the platform that allows the support portion to move or slide fore and aft with respect to the platform portion, an actuator coupled to the coupling structure to control the position of the support portion relative to the platform portion, a drive coupled to the at least one wheel to deliver power to the at least one wheel to propel the vehicle and maintain the platform at a desired orientation, and a controller coupled to the drive to control the drive and coupled to the actuator to control the actuator, the method comprising:

determining position of the coupling structure support portion relative to the position of the coupling assembly platform portion; and

controlling torque applied by the at least one wheel to an underlying surface by commanding the coupling structure to vary the position of the support portion relative to the platform portion while maintaining the platform at the desired orientation.

2. The method of claim 1, comprising specifying a specific position of the support portion relative to the platform portion to control the torque applied by the at least one wheel to the underlying surface to achieve a desired speed for the vehicle.

3. The method of claim 2, wherein the specific position is determined based on the vehicle operating mode.

4. The method of claim 1, comprising receiving a vehicle speed command value from a user or controller and varying the position of the support portion relative to the platform portion to control the torque applied by the at least one wheel to the underlying surface to achieve the vehicle speed command value.

5. The method of claim 1, comprising receiving speed feedback signals from the at least one wheel, coupling structure speed, or both to command the coupling structure to vary the position of the support portion relative to the platform portion to control the torque applied by the at least one wheel to the underlying surface to control the speed of the vehicle.

6. The method of claim 1, wherein the controller comprises a speed limiter module configured to constrain the size of a speed command signal to constrain the torque applied by the at least one wheel to the underlying surface to constrain the speed of the vehicle over a period of time in response to varying the position of the support portion relative to the platform portion over the period of time.

7. The method of claim 1, wherein the coupling structure is a slide assembly, the support portion is a rail, and the platform portion is a rail guide.

8. The method of claim 1, wherein the coupling structure is a four bar linkage.

9. A vehicle comprising:

a support;

at least one wheel;

a platform coupled to the at least one wheel;

a coupling structure having a support portion coupled to the support and a platform portion coupled to the platform that allows the support portion to move or slide fore and aft with respect to the platform portion;

an actuator coupled to the coupling structure to control the position of the support portion relative to the platform portion,

a drive coupled to the at least one wheel to deliver power to the at least one wheel to propel the vehicle and maintain the platform at a desired orientation; and

a controller coupled to the drive to control the drive and coupled to the actuator to control the actuator, wherein torque applied by the at least one wheel to an underlying surface vehicle is controlled by commanding the coupling structure to vary position of the support portion relative to the platform portion while maintaining the platform at the desired orientation.

10. The vehicle of claim 9, wherein the controller is configured to command a specific position of the support portion relative to the platform portion to control the torque applied by the at least one wheel to the underlying surface to achieve a desired speed for the vehicle.

11. The vehicle of claim 9, comprising an input device for receiving a vehicle speed command value from a user or controller and varying the position of the support portion relative to the platform portion to control the torque applied by the at least one wheel to the underlying surface to achieve the vehicle speed command value.

12. The vehicle of claim 9, comprising a wheel speed sensor and a coupling structure speed sensor to provide signals to the controller to command the coupling structure to vary the position of the support portion relative to the platform portion to control the torque applied by the at least one wheel to the underlying surface to control the speed of the vehicle.

13. The vehicle of claim 9, comprising a speed limiter module configured to command the controller to constrain the size of a speed command signal to constrain the torque applied by the at least one wheel to the underlying surface to constrain the speed of the vehicle over a period of time in response to varying the position of the support portion relative to the platform portion over the period of time.

14. The vehicle of claim 9, wherein the coupling structure is a slide assembly, the support portion is a rail, and the platform portion is a rail guide.

15. The vehicle of claim 9, wherein the coupling structure is a four bar linkage.

16. A method for maintaining a balancing margin for a dynamically-balancing vehicle, the vehicle comprising a support, at least one wheel, a platform coupled to the at least one wheel, a coupling structure having a support portion coupled to the support and a platform portion coupled to the platform that allows the support portion to move or slide fore and aft with respect to the platform portion, an actuator coupled to the coupling structure to control the position of the support portion relative to the platform portion, a drive coupled to the at least one wheel to dynamically balance the vehicle and provide power to the at least one wheel to propel the vehicle, and a controller coupled to the drive to control the drive and coupled to the actuator to control the actuator, the method comprising:

determining present operating wheel torque for the vehicle;

determining present wheel torque capability of the vehicle; and

controlling the coupling structure to control the position of the support portion relative to the platform portion based on the present operating wheel torque and the present wheel torque capability to maintain propulsion capability margins required for balancing the vehicle.

17. The method of claim 16, comprising enabling the coupling structure to only command positions that maintain balance of the vehicle.

18. The method of claim 17, wherein the coupling structure is enabled to only command positions where the sum of the present operating wheel torque and torque required for balancing the vehicle demands a motor current level which is below estimated available drive motor current of a power source used to power operation of the vehicle.

19. The method of claim 16, comprising controlling the speed of the vehicle based on commanded, measured or estimated fore/aft torque, yaw torque, or both.

20. The method of claim 16, wherein the coupling structure is a slide assembly, the support portion is a rail, and the platform portion is a rail guide.

21. The method of claim 16, wherein the coupling structure is a four bar linkage.

22. A dynamically-balancing vehicle, the vehicle comprising:

a support;

at least one wheel;

a platform coupled to the at least one wheel;

a coupling structure having a support portion coupled to the support and a platform portion coupled to the platform that allows the support portion to move or slide fore and aft with respect to the platform portion;

an actuator coupled to the coupling structure to control the position of the support portion relative to the platform portion,

a drive coupled to the at least one wheel to dynamically balance the vehicle and provide power to the at least one wheel to propel the vehicle; and

a controller coupled to the drive to control the drive and coupled to the actuator to control the actuator, wherein speed of the vehicle is controlled by commanding the coupling structure to control the position of the support portion relative to the platform portion based on present operating wheel torque for the vehicle and present wheel torque capability to maintain propulsion capability margins required for balancing the vehicle.

23. The vehicle of claim 22, comprising a position sensor to determine actual position of the support portion relative to the platform portion, wherein the controller compares position commands to the actual position and outputs actuator commands based on the comparison.

24. The vehicle of claim 22, comprising an effort limiter module coupled to the controller to enable the coupling structure to only command positions that maintain balance of the vehicle.

25. The vehicle of claim 24, wherein the effort limiter is configured to only enable the coupling structure to command positions where the sum of the present operating wheel torque and the torque required for balancing the vehicle demands a motor current level which is below estimated available drive motor current of a power source used to power operation of the vehicle.

26. The vehicle of claim 22, comprising a user input for commanding fore/aft speed, yaw rate, or both, of the vehicle and the controller is configured to control the speed of the vehicle based on the commanded, measured or estimated fore/aft torque, yaw torque, or both.

27. The vehicle of claim 22, wherein the coupling structure is a slide assembly, the support portion is a rail, and the platform portion is a rail guide.

28. The vehicle of claim 22, wherein the coupling structure is a four bar linkage.

29. A method for balancing a dynamically-balancing vehicle, the vehicle comprising a support, at least one ground-contacting element, a platform coupled to the at least one ground-contacting element, a coupling structure having a support portion coupled to the support and a platform portion coupled to the platform that allows the support portion to move or slide fore and aft with respect to the platform portion, an actuator coupled to the coupling structure to control the position of the support portion relative to the platform portion, a drive coupled to the at least one ground-contacting element to dynamically balance the vehicle and deliver power to the at least one ground-contacting element to propel the vehicle, and a controller coupled to the drive to command the drive and coupled to the actuator to control the actuator, the method comprising:

determining position of the coupling structure support portion relative to the coupling structure platform portion; and

controlling position of the coupling structure support portion relative to the coupling structure platform portion to move position of the vehicle center of gravity while dynamically balancing the vehicle.

30. The method of claim 29, comprising moving the support portion relative to the platform portion to dynamically balance the vehicle while the vehicle is at a commanded rest position relative to an underlying surface and the support is at least substantially level.

31. The method of claim 29, comprising varying position of the support portion relative to the platform portion in response to a change in the position of the vehicle center of gravity.

32. The method of claim 29, wherein the step of controlling position of the support portion relative to the platform portion is performed in response to vehicle fore/aft speed commands, yaw rate commands, or both, satisfying one or more predetermined conditions.

33. The method of claim 29, wherein the step of controlling position of the support portion relative to the platform portion is performed when the vehicle is operating in a predetermined mode of operation.

34. The method of claim 29, comprising disabling the step of controlling position during vehicle takeoff and landing modes.

35. The method of claim 34, comprising enabling the step of controlling position after the vehicle enters a balancing mode from the takeoff mode.

36. The method of claim 29, wherein the coupling structure is a slide assembly, the support portion is a rail, and the platform portion is a rail guide.

37. The method of claim 29, wherein the coupling structure is a four bar linkage.

38. A dynamically-balancing vehicle, the vehicle comprising:

a support;

at least one ground-contacting element;

a platform coupled to the at least one ground-contacting element;

a coupling structure having a support portion coupled to the support and a platform portion coupled to the platform that allows the support portion to move or slide fore and aft with respect to the platform portion;

an actuator coupled to the coupling structure to control the position of the support portion relative to the platform portion;

a drive coupled to the at least one ground-contacting element to dynamically balance the vehicle and provide power to the at least one ground-contacting element to propel the vehicle; and

a controller coupled to the drive to control the drive and coupled to the actuator to control the actuator, and wherein the controller balances the vehicle by determining position of the coupling structure support portion relative to the coupling structure platform portion and controlling position of the coupling structure support portion relative to the coupling structure platform portion to move position of the vehicle center of gravity while dynamically balancing the vehicle.

39. The vehicle of claim 38, wherein the controller is configured to move the support portion relative to the platform portion to dynamically balance the vehicle while the vehicle is at a commanded rest position relative to an underlying surface and the support is at least substantially level.

40. The vehicle of claim 38, wherein the controller is configured to vary position of the support portion relative to the platform portion in response to a change in the position of the vehicle center of gravity.

41. The vehicle of claim 38, wherein the step of controlling position of the support portion relative to the platform portion is performed in response to vehicle fore/aft speed commands, yaw rate commands, or both, satisfying one or more predetermined conditions.

42. The system of claim 38, wherein the step of controlling position of the support portion relative to the platform portion is performed when the vehicle is operating in a predetermined mode of operation.

43. The system of claim 38, wherein the controller is configured to disable the step of controlling position during vehicle takeoff and landing modes.

44. The system of claim 43, wherein the controller is configured to enable the step of controlling position after the vehicle enters a balancing mode from the takeoff mode.

45. The vehicle of claim 38, wherein the coupling structure is a slide assembly, the support portion is a rail, and the platform portion is a rail guide.

46. The vehicle of claim 38, wherein the coupling structure is a four bar linkage.

47. A method for determining motor current capability for a battery powered vehicle, the method comprising:

estimating a sagged battery voltage for a vehicle battery during operation based on;

a) a predetermined maximum expected battery bus current of the vehicle battery during operation,

b) an estimated battery open-circuit voltage, and

c) an estimated battery open-circuit resistance; and

estimating motor current capability for the battery powered vehicle based on;

d) operational speed of a motor used to propel the battery powered vehicle,

e) back EMF constant of the motor windings,

f) electrical resistance of the motor windings,

g) the sagged battery voltage,

h) electrical inductance of the motor windings, and

i) magnetic pole pair count for the motor.

48. The method of claim 47, wherein the sagged battery voltage for a vehicle battery during operation is estimated in accordance with:

V<sub>bat—

sag</sub>=V_OC−

I<sub>bat—

max</sub>*R_bat,

where V<sub>bat—

sag</sub> is the estimated sagged battery voltage, V_OC is estimated battery open-circuit voltage, I<sub>bat—

max</sub> is the predetermined maximum expected battery bus current, and R_bat is the estimated battery open-circuit resistance.

49. The method of claim 48, wherein the motor current capability for the battery powered vehicle is estimated in accordance with:

50. The method of claim 49, comprising limiting the motor current capability for the battery powered vehicle based on a current limit of a motor drive for driving the motor in accordance with:

I<sub>mot—

cap</sub>(Spd)=min(I<sub>mot—

lim</sub>, I<sub>mot—

max</sub>(Spd))

where I<sub>mot—

lim</sub> is the current limit of the motor drive.

51. The method of claim 49, comprising limiting the value of the operating speed of the motor used to a maximum no-load speed of the motor based on V_bat—

_sag in accordance with;

52. An apparatus for determining motor current capability for a battery powered vehicle, the apparatus comprising:

a measurement module configured to;

measure operational speed of a motor used to propel the battery powered vehicle; and

an estimation module configured to;

estimate a sagged battery voltage for a vehicle battery during operation based on;

a) a predetermined maximum expected battery bus current,

b) an estimated battery open-circuit voltage,

c) an estimated battery open-circuit resistance; and

estimate motor current capability for the battery powered vehicle based on;

d) operational speed of a motor used to propel the battery powered vehicle,

e) back EMF constant of the motor windings,

f) electrical resistance of the motor windings,

g) the sagged battery voltage,

h) electrical inductance of the motor windings, and

i) magnetic pole pair count for the motor.

53. The apparatus of claim 52, wherein the estimation module is configured to estimate the sagged battery voltage for a vehicle battery during operation in accordance with:

V<sub>bat—

sag</sub>=V_OC−

I<sub>bat—

max</sub>*R_bat,

where V<sub>bat—

sag</sub> is the estimated sagged battery voltage, V_OC is estimated battery open-circuit voltage, I<sub>bat—

max</sub> is the predetermined maximum expected battery bus current, and R_bat is the estimated battery open-circuit resistance.

54. The apparatus of claim 53, wherein the estimation module is configured to estimate the motor current capability for the battery powered vehicle in accordance with:

55. The apparatus of claim 54, wherein the estimation module is configured to limit the motor current capability for the battery powered vehicle based on a current limit of a motor drive for driving the motor in accordance with:

I<sub>mot—

cap</sub>(Spd)=min(I<sub>mot—

max</sub>(Spd))

where I<sub>mot—

lim</sub> is the current limit of the motor drive.

56. The apparatus of claim 54, wherein the estimation module is configured to limit the value of the operating speed of the motor used to a maximum no-load speed of the motor based on V_bat—

_sag in accordance with;

57. A method for estimating an electrical state of a battery providing power to an electrical load, the method comprising:

a) acquiring values of the battery voltage and the battery current draw at a first point in time;

b) monitoring battery voltage and battery current draw;

c) acquiring values of the battery voltage and battery current draw at a second point in time when the change in battery voltage between the first and second points in time is greater than a predetermined voltage amount and the change in battery current draw between the first and second points in time is greater than a predetermined current amount;

d) calculating battery resistance based on the change in battery voltage and battery current draw between the first and second points in time; and

e) calculating open-circuit battery voltage based on the calculated battery resistance, the battery current draw at the second point in time, and the battery voltage at the second point in time.

58. The method of claim 57, comprising:

repeating step b);

f) acquiring values of the battery voltage and battery current draw at a third point in time when the change in battery voltage between the second and third points in time is greater than the predetermined voltage amount and the change in battery current draw between the second and third points in time is greater than the predetermined current amount;

repeating step d); and

repeating step e).

59. The method of claim 57, comprising:

repeating step b);

and

f) postponing acquiring values of the battery voltage and battery current draw at a third point in time until the change in battery voltage between the second and third points in time is greater than the predetermined voltage amount and the change in battery current draw between the second and third points in time is greater than the predetermined current amount.

60. The method of claim 57, wherein step e) comprises determining whether a presently calculated battery resistance has changed by more than a predetermined percentage from a previously calculated battery resistance.

61. The method of claim 60, comprising calculating open-circuit battery voltage based on the calculated battery resistance if the presently calculated battery resistance has not changed by more than a predetermined percentage relative to the previously calculated battery resistance.

62. The method of claim 60, comprising calculating open-circuit battery voltage based on the previously calculated battery resistance if the presently calculated battery resistance has changed by more than a predetermined percentage relative to the previously calculated battery resistance.

63. The method of claim 57, comprising suspending steps c), d) and e) during predetermined operating conditions for a vehicle being power by the battery.

64. The method of claim 63, wherein steps c), d) and e) are suspended when the vehicle is regeneratively braking for a predetermined period of time.

65. An apparatus for estimating an electrical state of a battery providing power to an electrical load, the apparatus comprising:

a measurement module configured to a) acquire values of the battery voltage and the battery current draw at a first point in time, b) monitor battery voltage and battery current draw, and c) acquire values of the battery voltage and battery current draw at a second point in time when the change in battery voltage between the first and second points in time is greater than a predetermined voltage amount and the change in battery current draw between the first and second points in time is greater than a predetermined current amount; and

an estimation module configured to d) calculate battery resistance based on the change in battery voltage and battery current draw between the first and second points in time and e) calculate open-circuit battery voltage based on the calculated battery resistance, the battery current draw at the second point in time, and the battery voltage at the second point in time.

66. The apparatus of claim 65, wherein the measurement module is configured to repeat step b), f) acquire values of the battery voltage and battery current draw at a third point in time when the change in battery voltage between the second and third points in time is greater than the predetermined voltage amount and the change in battery current draw between the second and third points in time is greater than the predetermined current amount, repeat step d);

and repeat step e).

67. The apparatus of claim 65, wherein:

the measurement module is configured to repeat step b), and

the estimation module is configured to f) postpone acquiring values of the battery voltage and battery current draw at a third point in time until the change in battery voltage between the second and third points in time is greater than the predetermined voltage amount and the change in battery current draw between the second and third points in time is greater than the predetermined current amount.

68. The apparatus of claim 65, wherein the measurement module is configured to determine whether a presently calculated battery resistance has changed by more than a predetermined percentage from a previously calculated battery resistance.

69. The apparatus of claim 68, wherein the estimation module is configured to calculate open-circuit battery voltage based on the calculated battery resistance if the presently calculated battery resistance has not changed by more than a predetermined percentage relative to the previously calculated battery resistance.

70. The apparatus of claim 68, wherein the estimation module is configured to calculate open-circuit battery voltage based on the previously calculated battery resistance if the calculated battery resistance has changed by more than a predetermined percentage relative to the previously calculated battery resistance.

71. The apparatus of claim 65, wherein the apparatus is configured to suspend steps c), d) and e) during predetermined operating conditions for a vehicle being power by the battery.

72. The apparatus of claim 71, wherein the apparatus is configured to suspend steps c), d) and e) when the vehicle is regeneratively braking for a predetermined period of time.