Vehicle with independently adjustable suspension

1. A vehicle, comprising:

a frame structure;

four wheels; and

four independent suspension systems coupled to the frame structure and configured to support the wheels relative to the frame structure, each suspension system comprising:

a suspension arm movably coupling a respective wheel to the frame structure;

a torsion bar coupled to the suspension arm and imparting a spring force on the suspension arm;

a preload arm coupled to the torsion bar; and

a preload adjustment motor coupled to the preload arm and configured to rotate the torsion bar to adjust a preload on the torsion bar.

2. The vehicle of claim 1 , wherein:

the preload arm defines a set of gear teeth;

each independent suspension system further comprises a worm gear coupled to the preload adjustment motor and engaged with the set of gear teeth; and

the preload adjustment motor is configured to adjust the preload on the torsion bar by rotating the worm gear against the set of gear teeth, thereby rotating the preload arm.

3. The vehicle of claim 1 , wherein the suspension arm is an A-arm.

4. The vehicle of claim 1 , wherein the vehicle is configured to lower the frame structure onto a rigid support structure by reducing the preload on the torsion bar of each of the four independent suspension systems.

5. The vehicle of claim 1 , wherein the vehicle is configured to increase the preload on the torsion bar of each of the four independent suspension systems in response to detecting additional payload weight on the vehicle.

6. The vehicle of claim 5 , wherein the increasing of the preload on the torsion bar of each of the four independent suspension systems substantially maintains a ride height of the vehicle despite the additional payload weight.

7. The vehicle of claim 1 , wherein the vehicle is configured to increase the preload on the torsion bars of at least two of the four independent suspension systems in response to detecting a roll motion of the vehicle.

8. The vehicle of claim 1 , wherein the vehicle is configured to increase the preload on the torsion bars of at least two of the four independent suspension systems in response to detecting a pitch motion of the vehicle.

9. The vehicle of claim 1 , wherein:

each suspension system further comprises:

a nut coupled to the preload arm; and

a screw engaged with the nut and configured to be rotated by the preload adjustment motor; and

the preload adjustment motor is configured to adjust the preload on the torsion bar by rotating the screw within the nut, thereby rotating the preload arm.

10. A vehicle, comprising:

a frame structure;

a first pair of wheels proximate a first end of the vehicle and configured to steer the vehicle when the vehicle is travelling in a direction of the first end of the vehicle;

a second pair of wheels proximate a second end of the vehicle and configured to steer the vehicle when the vehicle is travelling in a direction of the second end of the vehicle; and

a respective suspension system for each wheel of the first pair of wheels and the second pair of wheels, each respective suspension system comprising:

a respective suspension arm movably coupling a respective wheel to the frame structure;

a respective torsion bar imparting a spring force on the respective suspension arm;

a respective preload arm coupled to the respective torsion bar; and

a respective preload adjustment motor configured to rotate the respective torsion bar to adjust a preload on the respective suspension system.

11. The vehicle of claim 10 , further comprising a ride height sensor associated with each respective suspension system.

12. The vehicle of claim 10 , further comprising a respective electric drive motor configured to drive each wheel of the first pair of wheels and the second pair of wheels.

13. The vehicle of claim 10 , wherein the vehicle is configured to increase the preload on the torsion bars of the suspension systems of the first pair of wheels in response to detecting a pitch motion of the vehicle.

14. The vehicle of claim 10 , wherein the vehicle is configured to:

detect a change in a loading weight of the vehicle; and

in response to detecting the change in the loading weight of the vehicle, change the preloads of the respective suspension systems to maintain a ride height of the vehicle.

15. A vehicle, comprising:

a frame structure;

four wheels; and

four independent suspension systems, each of the four independent suspension systems coupled to a respective wheel of the four wheels, wherein:

during a loading operation, the vehicle is configured to:

detect a change in a load weight of the vehicle; and

in response to detecting the change in the load weight of the vehicle, dynamically change the preloads of the four independent suspension systems to maintain a ride height of the vehicle.

16. The vehicle of claim 15 , wherein the loading operation corresponds to an operation in which passengers enter the vehicle.

17. The vehicle of claim 15 , wherein, during a driving operation, the vehicle is configured to maintain the preloads of the four independent suspension systems.

18. The vehicle of claim 15 , wherein, during a maintenance operation, the vehicle is configured to reduce the preloads of the four independent suspension systems to lower the vehicle onto a hard stop below the vehicle.

19. The vehicle of claim 15 , wherein the four wheels comprise:

a first pair of wheels proximate a first end of the vehicle and configured to steer the vehicle when the vehicle is travelling in a direction of the first end of the vehicle; and

a second pair of wheels proximate a second end of the vehicle and configured to steer the vehicle when the vehicle is travelling in a direction of the second end of the vehicle.

20. The vehicle of claim 15 , wherein:

a given independent suspension system of the four independent suspension systems comprises:

a torsion bar;

a preload arm coupled to the torsion bar; and

a preload adjustment motor configured to move the preload arm to adjust the preload of the given independent suspension system; and

the given independent suspension system is configured to maintain the preload arm in a stable position when the preload adjustment motor is not moving the preload arm to adjust the preload of the given independent suspension system.