Vehicle wheel assembly

1. A wheel assembly for a vehicle, comprising:

a plurality of wheel sub-assemblies, wherein each wheel sub-assembly includes:

only one single wheel;

a rotary drive module having a rotation axis, each wheel sub-assembly configured to be connected to a chassis via the rotary drive module;

a rotatable arm configured to extend radially from the rotation axis of the rotary drive module to couple the rotary drive module to the wheel, the rotary drive module being operable to drive rotation of the rotatable arm about the rotation axis of the rotary drive module, to rotate the wheel fully about the rotation axis in a climbing operation;

a control module having means for sensing stepped terrain, and being configured to respond to sensing stepped terrain by controlling the rotary drive modules of the plurality of wheel sub-assemblies such that a rotation of a respective wheel about a respective rotation axis will enable a vehicle supported by the plurality of wheel sub-assemblies to travel over the stepped terrain; and

means for driving the wheel assembly linearly through rotation of at least one of the plurality of powered wheels about an axis through a center of the at least one of the powered wheels,

wherein the wheels of the plurality of wheel sub-assemblies include:

non-steerable wheels powered by a motor and steerable wheels not powered by a motor, and

wherein the control module is configured to control each of the rotary drive modules of the plurality of wheel sub-assemblies such that the respective wheels coupled to the rotary drive modules will move in a sequence representative of a walking gait, such that at least two of the wheels of the plurality of wheel sub-assemblies will be positioned on terrain and at least one of the wheels of the plurality of wheel sub-assemblies will be out of contact with that terrain at a point in time during the sequence.

2. A wheel assembly according to claim 1 , wherein the control module is configured to control at least two of the rotary drive modules of the plurality of wheel sub-assemblies simultaneously.

3. A wheel assembly according to claim 2 , comprising:

a mechanism for controlling coupling of wheels of the plurality of wheel sub-assemblies to respective rotatable arms, so as to maintain the wheels in a fixed orientation relative to the wheel assembly when they rotate about the rotation axes of their respective rotary drive modules.

4. A wheel assembly according to claim 2 , wherein the control module is configured to control the means for driving the wheel assembly linearly to drive the wheel assembly while at least one of the plurality of wheels is arranged in a position which is not in contact with terrain.

5. A wheel assembly according to claim 1 , comprising:

a mechanism for controlling coupling of wheels of the plurality of wheel sub-assemblies to respective rotatable arms, so as to maintain the wheels in a fixed orientation relative to the wheel assembly when they rotate about the rotation axes of their respective rotary drive modules.

6. A wheel assembly according to claim 1 , wherein the control module is configured to control the means for driving the wheel assembly linearly to drive the wheel assembly while at least one of the plurality of wheels is arranged in a position which is not in contact with terrain.

7. A wheel assembly according to claim 1 in combination with a vehicle, wherein the control module comprises:

means for determining a center of mass of the vehicle supported by the wheel assembly, and for controlling each of the drive modules of the plurality of wheel sub-assemblies such that as the vehicle moves across terrain, a position of a center of mass of the wheel assembly is such that the vehicle will remain balanced.

8. A wheel assembly according to claim 7 , wherein the means for sensing stepped terrain comprises:

infrared and/or optical sensors.

9. A wheel assembly according to claim 8 , wherein the control module is configured with terrain profiles, and is configured to recognize a stored terrain profile using the sensing means.

10. A wheel assembly according to claim 8 , wherein the control module is configured with information relating to dimensions of the wheel assembly and a vehicle supported by the wheel assembly, and is configured to determine and output an indication of whether or not it is possible for the vehicle to travel over sensed terrain based on the stored information.

11. A wheel assembly according to claim 1 , wherein each of the wheels of the plurality of wheel sub-assemblies has freedom to rotate around one or more revolutions of its respective rotation axis.

12. A vehicle comprising:

a vehicle chassis; and

the wheel assembly of claim 1 .

13. A vehicle according to claim 12 , configured as a wheelchair, comprising:

an override mechanism for allowing a user of the wheelchair to override control of the control means to enable manual control of the plurality of wheel sub-assemblies.

14. A vehicle according to claim 13 , comprising:

contact surfaces on the chassis of the vehicle to support the vehicle on the terrain during a sequence of movements of the plurality of wheels.