Apparatus and Method for Controlling Vehicle Motion

• US 20090105908A1
• Filed: 10/20/2008
• Published: 04/23/2009
• Est. Priority Date: 10/19/2007
• Status: Abandoned Application

• Current Assignee: Segway Incorporated (Ninebot Ltd.)
• Original Assignee: Segway Incorporated (Ninebot Ltd.)
• Inventors: Morrell, John B., Casey, Robert, Stevens, Jon M., Gansler, Michael T., Kaufman, Michael F.
• Application Number:
  US12/254,178
• Publication Number:
  US 20090105908A1
• Time in Patent Office: Days
• US Class Current: 701/41
• CPC Class Codes: A63C 17/08 single-wheel type with single axis
• CPC Class Codes: A63C 17/12 with driving mechanisms
• 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 2200/16 Single-axle vehicles
• CPC Class Codes: B60L 2220/46 Wheel motors, i.e. motor connected to only one wheel
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 2240/22 Yaw angle
• CPC Class Codes: B60L 2240/24 Steering angle
• CPC Class Codes: B60L 2250/22 by presence detection
• CPC Class Codes: B60L 2260/34 Stabilising upright position of vehicles, e.g. of single axle vehicles
• CPC Class Codes: B62K 11/007 Automatic balancing machines with single main ground engaging wheel or coaxial wheels supporting a rider
• CPC Class Codes: B62K 3/00 Bicycles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

An apparatus and method for controlling a steering command of a vehicle is provided. A deadband value based on a current state of a transporter is applied to a roll compensated steering command to control steering of the vehicle. A gain is applied to a steering command to control steering of the vehicle.

Claims

1. A method for controlling a steering command of a transporter having at least one ground-contacting element, the method comprising:

determining an initialization roll deadband value based on initialization of an inertial state estimator of the transporter;

determining a velocity-based roll deadband value based on a velocity of the at least one ground-contacting element;

determining a total deadband value based on the initialization roll deadband value and the velocity-based roll deadband value; and

determining a roll compensated steering command signal based on the total deadband value.

2. The method of claim 1, comprising outputting the roll compensated steering command signal to a propulsion system of the transporter to control steering of the transporter.

3. The method of claim 1, comprising determining a steering roll value based on a roll angle of the transporter and the total deadband value.

4. The method of claim 3, wherein determining the steering roll value comprises:

determining the difference between the total deadband value and the roll angle of the transporter if the roll angle of the transporter is greater than or equal to the total deadband value.

5. The method of claim 4, wherein determining the steering roll value comprises:

determining the sum of the total deadband value and the roll angle of the transporter if the roll angle of the transporter is less than the total deadband value.

6. The method of claim 5, wherein determining a roll compensated steering command signal comprises combining a steering command of the transporter and the steering roll value.

7. The method of claim 1, wherein the initialization roll deadband value is set to approximately three degrees in roll when the inertial state estimator of the transporter has not been initialized.

8. The method of claim 1, wherein the initialization roll deadband is set to approximately zero degrees in roll when the inertial state estimator of the transporter has been initialized.

9. The method of claim 1, wherein determining the velocity-based roll deadband value comprises:

setting the velocity-based roll deadband value substantially equal to a zero degrees in roll when the position of a user input device relative to a neutral position is outside a predetermined range of displacement values; and

increasing or decreasing the velocity-based roll deadband value to a predetermined maximum value when the position of the user input device relative to the neutral position is inside the predetermined range of displacement values.

10. The method of claim 9, wherein the increasing or decreasing of the velocity-based roll deadband value is increased or decreased linearly, quadratically, logarithmically, exponentially or any combination thereof.

11. A controller for steering a transporter having at least one ground-contacting element, the controller comprising:

a roll deadband compensation module having an output that is an initialization roll deadband value, the initialization roll deadband value is determined based on initialization of an inertial state estimator of the transporter;

a velocity-based roll deadband module having an input of a velocity of the at least one ground-contacting element and an output of a velocity-based roll deadband value, the velocity-based roll deadband value is determined based on the velocity of the at least one ground-contacting element; and

a total deadband module having inputs of the velocity-based roll deadband value and the initialization roll deadband value and an output of the total deadband value, the output is determined based on the velocity-based roll deadband value and the initialization roll deadband value; and

a roll compensated steering module having input of a total deadband value and an output of a roll compensated steering command signal, the output is determined based on the total deadband value.

12. The controller of claim 11, comprising a propulsion system having an input that receives the roll compensated steering command signal to control steering of the transporter.

13. The controller of claim 11, comprising a steering roll module having inputs of a roll angle of the transporter and the total deadband value and an output of a steering roll value, the output of a steering roll value is determined based on the roll angle and total deadband value.

14. The controller of claim 13, wherein the steering roll module comprises:

a summer to sum the roll angle of the transporter and the total deadband value if the roll angle of the transporter is greater than or equal to the total deadband value; and

a subtractor to difference the roll angle of the transporter and the total deadband value if the roll angle of the transporter is less than the total deadband value.

15. The controller of claim 14, wherein the roll compensated steering module comprises a summer to sum a steering command of the transporter and the steering roll value.

16. The controller of claim 11, wherein the initialization roll deadband value is set to approximately three degrees in roll when the inertial state estimator of the transporter has not been initialized.

17. The controller of claim 11, wherein the initialization roll deadband is set to approximately zero degrees in roll when the inertial state estimator of the transporter has been initialized.

18. The controller of claim 11, wherein determining the velocity-based roll deadband module comprises:

a zero input to set the velocity-based roll deadband value substantially equal to a zero degrees in roll when the position of a user input device relative to a neutral position is outside a predetermined range of displacement values; and

a function module to increase or decrease the velocity-based roll deadband value to a predetermined maximum value when the position of the user input device relative to the neutral position is inside the predetermined range of displacement values.

19. The controller of claim 18, wherein the increase or decrease of the velocity-based roll deadband is increased or decreased linearly, quadratically, logarithmically, exponentially or any combination thereof.

20. A method for controlling a steering command of a transporter having at least one ground-contacting element, the method comprising:

determining a step gain value of a transporter, the step gain value is set equal to a step on gain value if a rider is stepping on to the transporter or a step off gain value if the rider is stepping off of the transporter;

determining a mount state value of the transporter, the mount state value is based on whether the rider has one or two feet on the transporter;

determining a reduction gain value based on an operation mode value of the transporter, a velocity of the at least one ground-contacting element and the mount state value;

determining a yaw rate reduction gain, the yaw rate reduction gain is the minimum of the reduction gain value and the step gain value; and

determining a transporter steering command based on the yaw rate reduction gain.

21. The method of claim 20, wherein the operation mode value corresponds to one of a beginner mode.

22. The method of claim 20, wherein the step mode value is set equal to the step on gain value if rider detect sensors coupled to the transporter detect when a first foot of the rider is on the transporter and a second foot of the rider is off the transporter.

23. The method of claim 22, wherein the step mode value is set equal to the step off gain value if:

a) rider detect sensors coupled to the transporter detect when a first foot of the rider is on the transporter and a second foot of the rider is off the transporter; and

b) a steering command signal of the transporter is in a direction towards the first foot of the rider that is on the transporter when the steering command signal approaches a value to cause a platform of the transporter to rotate over the second foot.

24. The method of claim 23, wherein determining the step off gain value comprises:

multiplying a side step off gain value by the difference between a current steering command signal and a side step off angle value; and

subtracting a zero angle gain value from the resultant of the multiply.

25. The method of claim 23, wherein determining the side step off gain value comprises:

determining a side step off angle difference value by taking a difference between the zero angle gain value of the transporter and the current steering command signal; and

multiplying the side step off angle difference value by a side step angle value divided by the zero angle gain value.

26. A controller for steering a transporter having at least one ground-contacting element, the controller comprising:

a step mode module to compute a step gain value output, the step gain value output is a step on gain value if a rider is stepping on to the transporter and a step off gain value if the rider is stepping off of the transporter;

a reduction gain module to compute a reduction gain value output based on inputs of an operation mode value of the transporter, a velocity of the at least one ground-contacting element and a mount state, the mount state value is based on whether the rider has one or two feet on the transporter;

a comparator to determine a yaw rate reduction gain value, the yaw rate reduction gain value is the minimum of the reduction gain value and the step gain value; and

a steering module that computes a transporter steering command based on the yaw rate reduction gain value.

27. The controller of claim 26, wherein the operation mode value corresponds to one of a beginner mode.

28. The controller of claim 26, comprising:

rider detect sensors coupled to the transporter to detect when a first foot of the rider is on the transporter and a second foot of the rider is off the transporter to determine the step mode value is a step on gain value.

29. The controller of claim 28, comprising:

a rider detect sensor to detect when a first foot of the rider is on the transporter and a second foot of the rider is off the transporter; and

the step mode module to determine that a steering command signal of the transporter is in a direction towards the first foot of the rider that is off the transporter when the steering command signal approaches a value to cause a platform of the transporter to rotate over the second foot to determine the step mode value is a step off gain value.

30. The controller of claim 29, wherein the step mode module comprises:

a multiplier to multiply a side step off gain by the difference between a current steering command signal and a side step off angle value; and

a subtractor to subtract a zero angle gain value from the resultant of the multiplier to compute the step off gain value.

31. The controller of claim 30, wherein the step mode module comprises:

a side step off angle difference module to determining a side step off angle difference value by taking a difference between the zero angle gain value of the transporter and the current steering command signal; and

a multiplier to multiply the side step off angle difference value by a side step angle value divided by the zero angle gain value to compute the side step off reduction gain scale value.

32. A controller for steering a transporter having at least one ground-contacting element, the controller comprising:

means for determining an initialization roll deadband value based on if an inertial state estimator of the transporter has been initialized;

means for determining a velocity-based roll deadband value based on the velocity of the at least one ground-contacting element;

means for determining a total deadband value based on the velocity-based roll deadband value and the initialization roll deadband value;

means for determining a steering roll value based on a roll angle of the transporter and the total deadband value; and

means for determining a roll compensated steering command signal based on the steering roll value.

33. A method for controlling a steering command of a transporter having at least one ground-contacting element, the method comprising:

determining an initialization roll deadband value based on initialization of a roll state estimator of the transporter;

determining a velocity-based roll deadband value based on a velocity of the at least one ground-contacting element;

determining a total deadband value based on the initialization roll deadband value and the velocity-based roll deadband value; and

determining a roll compensated steering command signal based on the total deadband value.