Mobility device

1. A method for controlling speed of a mobility device, the mobility device including a plurality of wheels, at least one cluster assembly, and a plurality of sensors, the method comprising:

receiving terrain and obstacle detection data from the plurality of sensors;

mapping terrain and obstacles, if any, in real time based at least on terrain and obstacle detection data;

computing collision-possible areas, if any, based at least on the mapped data;

computing slow-down areas if any, based at least on the mapped data and the speed of the mobility device;

receiving user preferences, if any, with respect to the slow-down areas and desired direction and speed of motion;

computing movement commands to command the plurality of wheels based at least on the collision possible areas, the slow-down areas, and the user preferences; and

providing the movement commands to the plurality of wheels.

2. The method for controlling the speed as in claim 1 further comprising:

estimating a center of gravity of the mobility device;

estimating at least one value associated with the mobility device, the estimated at least one value required to maintain balance of the mobility device based on the estimated center of gravity;

computing mobility device acceleration of the mobility device based at least on a wheel speed of the plurality of wheels; and

computing at least one inertial sensor acceleration of at least one inertial sensor mounted upon the mobility device based at least on sensor data from the at least one inertial sensor;

computing a difference between the mobility device acceleration and the inertial sensor acceleration;

comparing, forming a comparison, the difference to a pre-selected threshold; and

commanding the at least one cluster assembly to drop at least one of the plurality of wheels and a caster wheel assembly to ground based at least on the comparison.

3. The method for controlling the speed as in claim 2 further comprising:

receiving an indication that the mobility device is encountering a ramp between ground and a vehicle;

directing the at least one cluster assembly to maintain a first contact of the plurality of wheels with the ground based on the encountering the ramp;

changing an orientation of the at least one cluster assembly based on the encountering the ramp and according to the estimated at least one value required to maintain balance of the mobility device based on a position of the plurality of wheels on the ramp;

dynamically adjusting a distance between a seat and the at least one cluster assembly based on the encountering the ramp to prevent a second contact between the seat and the plurality of wheels while maintaining the seat as close to the ground as possible while on the ramp.

4. The method for controlling the speed as in claim 1 further comprising:

operably coupling the at least one cluster assembly to a powerbase assembly;

operably coupling the at least one cluster assembly to the plurality of wheels;

supporting, by the plurality of wheels, the powerbase assembly, the plurality of wheels and the at least one cluster assembly; and

moving the mobility device based at least on the movement commands.

5. The method for controlling the speed as in claim 4 further comprising:

providing, by field weakening, bursts of power to motors associated with the at least one cluster assembly and the plurality of wheels.

6. The method for controlling the speed as in claim 4 further comprising:

estimating a center of gravity of the mobility device including:

(a) measuring data including a pitch angle required to maintain balance of the mobility device at a cluster pre-selected position of the at least one cluster assembly and a seat pre-selected position of a seat associated with the mobility device;

(b) moving the mobility device to a plurality of points;

(c) repeating step (a) at each of the plurality of points;

(d) verifying that the measured data fall within pre-selected limits; and

(e) generating a set of calibration coefficients to establish the center of gravity during operation of the mobility device, the set of calibration coefficients based at least on the verified measured data.

7. The method for controlling the speed as in claim 6 further comprising:

maintaining stability of the mobility device; and

automatically decelerating forward motion and accelerating backward motion under pre-selected circumstances, the pre-selected circumstances being based on the pitch angle of the mobility device and the center of gravity of the mobility device.

8. The method for controlling the speed as in claim 4 further comprising:

moving the at least one cluster assembly and the plurality of wheels by redundant motors;

sensing sensor data from the redundant motors and the at least one cluster assembly by redundant sensors;

selecting information, by redundant of at least one processor executing within the powerbase assembly collecting the sensor data from the redundant sensors, based on agreement of the sensor data among the redundant of the at least one processor; and

processing by the redundant of the at least one processor, the movement commands based at least on the selected information.

9. The method for controlling the speed as in claim 8 further comprising:

sensing substantially similar characteristics of the mobility device by the redundant sensors.

10. The method for controlling the speed as in claim 1 further comprising:

limiting, by user-configurable drive options, the speed and a mobility device acceleration based on pre-selected circumstances.

11. The method for controlling the speed as in claim 1 further comprising:

modifying at least one speed range for the mobility device by a thumbwheel operably coupled with a user-control device.

12. A method for moving a mobility device on relatively steep terrain, the mobility device including clusters of wheels and a seat, the clusters of wheels and the seat separated by a distance, the distance varying based on pre-selected characteristics, the method comprising:

receiving an indication that the mobility device will encounter the steep terrain;

directing the clusters of wheels to maintain contact with ground; and

dynamically adjusting the distance based on maintaining balance of the mobility device and the indication.

13. The method for moving a mobility device as in claim 12 further comprising:

estimating a center of gravity of the mobility device;

estimating at least one value associated with the mobility device, the estimated at least one value required to maintain the balance of the mobility device based on the estimated center of gravity;

computing mobility device acceleration of the mobility device based at least on a speed of the clusters of wheels; and

computing at least one inertial sensor acceleration of at least one inertial sensor mounted upon the mobility device based at least on sensor data from the at least one inertial sensor;

computing a difference between the mobility device acceleration and the inertial sensor acceleration;

comparing, forming a comparison, the difference to a pre-selected threshold; and

commanding the clusters of wheels and a caster wheel assembly to ground based at least on the comparison.

14. The method for moving the mobility device as in claim 12 further comprising:

providing, by field weakening, bursts of power to motors associated with the clusters of wheels.

15. The method for moving the mobility device as in claim 12 further comprising:

estimating a center of gravity of the mobility device including:

(a) measuring data including a pitch angle required to maintain the balance of the mobility device at a cluster pre-selected position of the clusters of wheels and a seat pre-selected position of the seat;

(b) moving the mobility device to a plurality of points;

(c) repeating step (a) at each of the plurality of points;

(d) verifying that the measured data fall within pre-selected limits; and

(e) generating a set of calibration coefficients to establish the center of gravity of the mobility device during operation of the mobility device, the set of calibration coefficients based at least on the verified measured data.

16. The method for moving the mobility device as in claim 15 further comprising:

maintaining stability of the mobility device; and

automatically decelerating forward motion and accelerating backward motion under pre-selected circumstances, the pre-selected circumstances being based on the pitch angle of the mobility device and the center of gravity of the mobility device.

17. The method for moving the mobility device as in claim 15 further comprising:

moving the clusters of wheels by redundant motors;

sensing sensor data from the redundant motors and the clusters of wheels by redundant sensors;

selecting information based on agreement of the sensor data among the redundant sensors; and

commanding the mobility device based at least on the selected information.

18. The method for moving the mobility device as in claim 17 further comprising:

sensing substantially similar characteristics of the mobility device by the redundant sensors.

19. The method for moving the mobility device as in claim 12 further comprising:

limiting, by user-configurable drive options, the speed and a mobility device acceleration based on pre-selected circumstances.

20. The method for moving the mobility device as in claim 12 further comprising:

modifying at least one speed range for the mobility device by a thumbwheel operably coupled with a user-control device.

21. The method for moving the mobility device as in claim 12 further comprising:

receiving a second indication that the mobility device is encountering a ramp between the ground and a vehicle;

directing the clusters of wheels to maintain a first contact with the ground based on the encountering the ramp;

changing an orientation of the clusters of wheels based on the encountering the ramp and according to at least one value required to maintain the balance of the mobility device based on a position of the clusters of wheels on the ramp;

dynamically adjusting a seat distance between the seat and the clusters of wheels based on the encountering the ramp to prevent a second contact between the seat and the clusters of wheels while maintaining the seat as close to the ground as possible while on the ramp.