Apparatus and methods for control of a vehicle

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.

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.

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.

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.

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.

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.

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.