System and method for control scheduling

• US 20040210328A1
• Filed: 04/21/2003
• Published: 10/21/2004
• Est. Priority Date: 05/28/1999
• Status: Active Grant

• Current Assignee: John B. Morrell
• Original Assignee: John B. Morrell
• Inventors: Morrell, John B.
• Granted Patent: US 7,130,702 B2
• Time in Patent Office: Days
• US Class Current: 700/90
• CPC Class Codes: A61G 5/061 for climbing stairs
• CPC Class Codes: A61G 5/063 with eccentrically mounted wheels
• CPC Class Codes: A61G 5/1054 Large wheels, e.g. higher than the seat portion
• CPC Class Codes: B60L 15/2009 for braking
• CPC Class Codes: B60L 50/52 characterised by DC-motors
• CPC Class Codes: B60L 50/60 using power supplied by batteries in combination with fuel cells B60L50/75
• CPC Class Codes: G05B 13/024 in which a parameter or coefficient is automatically adjusted to optimise the performance
• 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

A system and method for controlling a device such that device operates in a smooth manner. The system may switch between control architectures or vary gain coefficients used in a control loop to control the device. As the architecture or gains are switched, the control signal may be smoothed so that the device does not experience an abrupt change in the control signal it receives. In one embodiment, the control signal may be smoothed by adding a decaying offset value to the control signal to create a smoothed control signal that is applied to the device.

Claims

1. A system of converting between a first operating mode and a second operating mode in a device, system comprising:

a control loop which utilizes gain coefficients associated with the first operating mode to control the system in the first operating mode and utilizes gain coefficients associated with the second operating mode when operating in the second operating mode; and

a gain selector which causes the control loop to operate using the coefficients associated with the second operational mode at substantially the same instant that the device transitions from the first operational mode to the second operational mode.

2. The system of claim 1, wherein the gain selector determines whether the control loop utilizes the coefficients associated with the first mode or the coefficients associated with the second mode based upon a current operational mode of the device.

3. The system of claim 1, further comprising a gain table which is accessed by the control loop and contains the coefficients which are associated with a current mode of operation.

4. The system of claim 1, further comprising:

a smoother which smooths the output of the control loop before a control signal created by the control loop is provided to the device.

5. The system of claim 4, wherein the smoother adds a decaying offset value to the control signal.

6. The system of claim 5, wherein the offset value is determined by comparing a smoothed control signal applied to the device before the transition and a control signal created after the transition.

7. A method of smoothly operating a device that is responsive to a control signal, the method comprising steps of:

determining a value for the control signal;

processing the control signal to create a modified control signal; and

applying the modified control signal to the device.

8. The method of claim 7, wherein the control signal is determined by a control unit and the step of processing occurs after the step of determining.

9. The method of claim 7, further comprising steps of:

determining, before the step of processing, whether the device has changed modes of operation; and

if the device has changed modes, applying a decaying version of an offset value to the control signal in the step of processing.

10. A method of smoothly switching between modes in a multi-modular apparatus, the method comprising steps of:

determining whether a mode change has occurred;

determining an offset value if the mode has changed; and

adding a decaying version of the offset value to a control signal before the control signal is applied to the apparatus to create a smoothed control signal; and

applying the smoothed control signal to the apparatus.

11. The method of claim 10, wherein the offset value is equal to a difference between a last signal applied to the apparatus and a control signal generated after the mode change.

12. The method of claim 10, wherein the offset value is decayed by the steps of:

(a) multiplying a current offset value by a number less than one;

(b) updating the current offset to equal the result of the multiplication of step (a); and

(c) repeating steps (a) and (b).

13. The method of claim 12, wherein step (c) is repeated until the current offset value approaches a lower threshold.

14. The method of claim 13, wherein the lower threshold is approximately zero.

15. The method of claim 10, further comprising a step of:

storing smoothed control signal.

16. The method of claim 15, wherein a difference between the stored smoothed control signal and a control signal created after the apparatus has changed modes is used to determine the offset value.

17. The method of claim 16, further comprising steps of:

determining whether an offset value is currently decaying; and

replacing the currently decaying offset value with a new offset value when the apparatus changes modes.