Method and system for consistent braking control
Brake pedal input is modulated to produce a consistent relationship between the brake pedal input and a deceleration of the vehicle.
1. A method for controlling braking in a vehicle comprising:
receiving a brake pedal input;
modulating said brake pedal input by a feedback gain and a feed forward gain to create a modulated brake pedal input; and
braking said vehicle based upon said modulated brake pedal input;
wherein said feed forward gain comprises a load adaptation factor automatically estimating an effect of a dynamic load upon said vehicle based upon said feedback gain and said brake pedal input, and
wherein said modulated brake pedal input is operative to produce a consistent relationship between said brake pedal input and a deceleration of said vehicle.
2. The method of claim 1 , wherein said feedback gain comprises deceleration data derived from accelerometer data.
3. The method of claim 1 , wherein said feedback gain comprises deceleration data derived from global positioning data.
4. The method of claim 1 , wherein said feedback gain comprises deceleration data derived from accelerometer data and from global positioning data.
5. The method of claim 1 , wherein said feed forward gain comprises a road slope factor.
6. The method of claim 1 , wherein said dynamic load comprises a non-nominal load of said vehicle.
7. The method of claim 1 , wherein said load adaptation cycle is adjusted through a brake control adaptation cycle.
8. The method of claim 7 , wherein said brake control adaptation cycle comprises a key cycle of said vehicle beginning when said vehicle is keyed on and ending when said vehicle is keyed off.
9. The method of claim 7 , wherein said brake control adaptation cycle comprises an initial load adaptation factor based upon a nominal load of said vehicle and adjusts said load adaptation factor iteratively based upon a non-nominal load of said vehicle.
10. The method of claim 7 , wherein said brake control adaptation cycle comprises an initial load adaptation factor based upon a last load of said vehicle from a previous brake control adaptation cycle and adjusts said load adaptation factor iteratively based upon a non-nominal load of said vehicle.
11. The method of claim 7 , wherein said brake control adaptation cycle comprises a learning cycle comprising:
adjusting said load adaptation factor during said learning cycle; and
utilizing said adjusted load adaptation factor as a fixed value after said learning cycle.
12. The method of claim 1 , wherein automatically estimating said effect of said dynamic load upon said vehicle comprises updating said dynamic load of said vehicle based solely upon signals internal to said vehicle during operation of said vehicle.
13. A braking control system comprising:
a brake pedal system;
a data system operative to generate vehicle data, said vehicle data operative to produce vehicle deceleration data and road slope data;
a brake control module, said brake control module operative to:
receive a brake pedal input from said brake pedal system;
calculate a feedback gain based upon said vehicle deceleration data;
calculate a feed forward gain based upon said road slope data and a load adaptation factor; and
apply said feedback gain and said feed forward gain to said brake pedal input to generate a modulated brake pedal input; and
a braking-torque generating system responding to said modulated brake pedal input; and
wherein said load adaptation factor automatically estimates an effect of a dynamic load upon said vehicle based upon said feedback gain and said brake pedal input.
14. The system of claim 13 , wherein said data system comprises an accelerometer.
15. The system of claim 14 , wherein said data system further comprises a digital map device.
16. The system of claim 13 , wherein said data system comprises a digital map device.
17. The system of claim 13 , wherein said load adaptation factor is initially set to a pre-set lookup value.
18. The system of claim 13 , wherein said load adaptation factor is initially set to a last value of said load adaptation factor utilized during a previous brake control adaptation cycle.