Torque sensing for a steering system

1. A torque sensing subsystem for a steering system of a vehicle, comprising:

an input shaft connectable to a steering input subsystem;

an output shaft connectable to a steering output subsystem;

a torsion device connecting said input shaft and said output shaft and allowing relative rotational movement between said input shaft and said output shaft based upon a torque applied to said input shaft or said output shaft;

a first sensor for sensing relative rotational movement of said input shaft and the vehicle;

a second sensor for sensing relative movement of said output shaft and the vehicle; and

a computation unit in communication with said first sensor and said second sensor and configured to determine the magnitude and origination of the applied torque.

2. The subsystem of claim 1 , wherein an input indicator is located on said input shaft and an output locator is located on said output shaft, and said first sensor is adapted to sense movement of said input indicator and said second sensor is adapted to sense movement of said output indicator.

3. The subsystem of claim 2 , wherein said input indicator and said output indicator are barcodes.

4. The subsystem of claim 1 , wherein said first sensor and second sensor are optical sensors.

5. The subsystem of claim 1 , wherein said computation unit is adapted to transmit signals to a steer assist subsystem, which applies torque to the steering output subsystem.

6. A method of stabilizing a steering system of a vehicle including a steering input subsystem having a steering input device for a driver of the vehicle, a steering output subsystem having a road wheel, an input shaft coupled to the steering input device, and output shaft coupled to the road wheels, and a torsion device connecting the input shaft and the output shaft and allowing relative rotational movement between the input shaft and the output shaft based upon a torque applied to the input shaft or the output shaft, said method comprising;

measuring rotational movement of the input shaft relative to the vehicle, and measuring rotational movement of the output shaft relative to the vehicle;

converting the rotational movements into torque measurements based upon a predetermined relationship between applied torque and relative rotational movement of the input shaft and the output shaft;

determining whether the torque on the torsion device originated from a road surface through the road wheel or from the driver through the steering input device;

if the torque originated from the road surface, then reduce the external torque to the steering output subsystem by applying an opposing torque; and

if the torque originated from the driver, then increase the torque to the steering output subsystem by applying additional torque.

7. The method of claim 6 , wherein said act of reducing the torque to the steering output subsystem includes negating at least some of the torque.

8. A steering system for a vehicle, comprising:

a steering input subsystem;

a steering output subsystem;

an input shaft coupled to said steering input subsystem;

an output shaft coupled to said steering output subsystem;

a torsion device connecting said input shaft and said output shaft and allowing relative rotational movement between said input shaft and said output shaft based upon a torque applied to said input shaft or said output shaft;

a first sensor sensing the relative rotational movement of said input shaft and the vehicle;

a second sensor sensing the relative rotational movement of said output shaft and the vehicle; and

a computation unit in communication with said first sensor and said second sensor and configured to determine the magnitude and origination of the applied torque.

9. The system of claim 8 , wherein said steering input subsystem includes a steering wheel connected to said input shaft.

10. The system of claim 8 , wherein said steering output subsystem includes a rack-and-pinion device connecting said output shaft to a road wheel and adapted to actuate the road wheel.

11. The system of claim 8 , wherein an input indicator is located on said input shaft and an output indicator is located on said output shaft, and said first sensor is adapted to sense movement of said input indicator and said second sensor is adapted to sense movement of said output indicator.

12. The assembly of claim 11 , wherein said input indicator and said output indicator are barcodes.

13. The assembly of claim 8 , wherein said first sensor and second sensor are optical sensors.

14. The system of claim 8 , wherein said computation unit is adapted to transmit signals to a steer assist system, which applies torque to said steering output subsystem.

15. The system of claim 14 , wherein said steering output subsystem includes a rack-and-pinion device and the steer assist subsystem applies torque directly to said rack-and-pinion device.

16. A method of stabilizing a steering system of a vehicle including a steering output subsystem having a steering input device for a driver of the vehicle, a steering output subsystem having a road wheel, an input shaft coupled to the steering input device, an output shaft coupled to the road wheels, and a torsion device connecting the input shaft and the output shaft and allowing relative rotational movement between the input shaft and the output shaft based upon a torque applied to the input shaft of the output shaft, said method comprising:

measuring rotational movement of the input shaft relative to the vehicle, and measuring rotational movement of the output shaft relative to the vehicle

converting the rotational movements into torque measurements based upon a predetermined relationship between applied torque and relative rotational movement of the input shaft and the output shaft; and

determining whether the torque on the torsion device originated from a road surface through the road wheel or from the driver through the steering input device.

17. The method of claim 16 , further comprising applying torque to the steering output subsystem in accordance with the following rules:

if the torque originated from the road surface, then reduce the external torque to the steering output subsystem; and

if the torque originated from the driver, then increase the torque to the steering output subsystem by applying additional torque.