Torque distribution systems and methods for wheeled vehicles
View Patent ↗A system controls torques applied to a plurality of wheels of a motor vehicle. One or more angular velocity sensors determine speed for each of the plurality of wheels. A vehicle yaw acceleration sensor determines actual yaw acceleration of the vehicle. A desired yaw acceleration sensor determines intended yaw acceleration for the vehicle. A net torque command sensor determines intended vehicle direction and intended torque magnitude for the vehicle. An electronic control unit processes data from the velocity sensors, the vehicle yaw acceleration sensor, the desired yaw acceleration sensor and the net torque command sensor to generate torque signals for the plurality of wheels. One or more torque producers responds to the torque signals to vary torque applied to each of the plurality of wheels, such that the wheels engage in one of acceleration and deceleration dependent upon driver intent and with controlled traction. Torque distribution among a plurality of wheels limits wheel slip, improves traction, and produces a yaw moment to correct oversteer or understeer conditions.
1. A system for controlling torques applied to a plurality of wheels of a motor vehicle, comprising:
one or more speed sensors for determining speed for each of the plurality of wheels;
a vehicle yaw acceleration sensor for determining actual yaw acceleration of the vehicle;
a desired yaw acceleration sensor for determining intended yaw acceleration for the vehicle;
a net torque command sensor for determining intended vehicle direction and intended torque magnitude for the vehicle;
an electronic control unit for processing data from the speed sensors, the vehicle yaw acceleration sensor, the desired yaw acceleration sensor and the net torque command sensor to generate torque signals for the plurality of wheels; and one or more torque producers, responsive to the torque signals, to vary torque applied to each of the plurality of wheels such that the wheels engage in one of acceleration and deceleration dependent upon driver intent and with controlled traction.
2. The system of claim 1 , actual vehicle behavior being determined by the vehicle yaw acceleration sensor and the speed sensors, intended vehicle behavior being determined by the net torque command sensor and the desired yaw acceleration sensor, the electronic control unit comparing the actual vehicle behavior to the intended vehicle behavior to determine the torque signals such that the controlled traction reduces likelihood that one or more of the plurality of wheels slips or locks.
3. The system of claim 1 , the torque producers being one of a motor, a motor controller, a servo amplifier, an inverter, and mixtures thereof.
4. The system of claim 1 , the desired yaw acceleration sensor sensing one or more vehicle components of the vehicle.
5. The system of claim 4 , the desired yaw acceleration sensor sensing velocity of the vehicle.
6. The system of claim 4 , the desired yaw acceleration sensor sensing rate of change of angle of steered wheels relative to a body of the vehicle.
7. The system of claim 6 , the rate of change comprising a time derivative of δ f .
8. The system of claim 6 , the desired yaw acceleration sensor comprising one of an optical encoder, a potentiometer, a differentiator, and mixtures thereof.
9. The system of claim 6 , one or both of the electronic control unit and desired yaw acceleration sensor comprising computational means that processes a desired yaw acceleration based on the rate of change of angle and an approximate vehicle velocity based on wheel velocities.
10. The system of claim 4 , the desired yaw acceleration sensor utilizing vehicle velocity.
11. The system of claim 4 , the components comprising one or more of a steering wheel, steering linkage, drive-by-wire control switches and mixtures thereof.
12. The system of claim 1 , the speed sensors comprising one or more of optical encoders and magnetic induction sensors to measure angular velocity.
13. The system of claim 1 , the net torque command sensor determining intended longitudinal acceleration of the vehicle.
14. The system of claim 1 , the net torque command sensor sensing position of one or more vehicle components of the vehicle.
15. The system of claim 14 , the components comprising one or more of a vehicle accelerator pedal, gas pedal, brake pedal, drive selector, drive-by-wire control switches and mixtures thereof.
16. The system of claim 1 , the vehicle yaw acceleration sensor comprising one of a gyroscopic sensor, accelerometers, differentiating devices, and mixtures thereof.
17. The system of claim 1 , the electronic control unit comprising limit setting routine means and torque distribution routine means.
18. The system of claim 17 , the limit setting routine means generating limits for each of the torque producers based upon data from the speed sensors and the torque producers.
19. The system of claim 18 , the torque distribution routine means distributing torque among the plurality of wheels based in part upon the limits.
20. The system of claim 1 , the electronic control unit comprising torque distribution routine means for distributing torque among the plurality of wheels.
21. The system of claim 20 , the torque distribution routine means distributing torque among the plurality of wheels based in part upon data from the vehicle yaw acceleration sensor, the net toque command sensor and the desired yaw acceleration sensor.
22. The system of claim 1 , the electronic control unit determining a ratio of torque limits for each of the plurality of wheels to a sum of torque limits for the plurality of the wheels and distributing torque among the torque signals in achieving the controlled traction.
23. A software product comprising instructions, stored on computer-readable media, wherein the instructions, when executed by a computer, perform steps for controlling torque applied to wheels of a motor vehicle, comprising:
determining speed for each of the plurality of wheels;
determining actual yaw acceleration of the vehicle;
determining intended yaw acceleration for the vehicle;
determining intended vehicle direction and intended torque magnitude for the vehicle; and
processing actual yaw acceleration, intended yaw acceleration, and intended torque magnitude of the vehicle and rotational velocity of each of the wheels to generate torque signals for the plurality of wheels; such that the wheels engage in one of acceleration and deceleration dependent upon driver intent and with controlled traction.
24. The software product of claim 23 , further comprising determining a ratio of torque limits for each of the plurality of wheels to a sum of torque limits for the plurality of the wheels and distributing torque among the torque signals in achieving the controlled traction.
25. A system for distributing torque to a plurality of wheels of a motor vehicle, comprising:
limit setting routine means for receiving signals indicative of rotational velocity for each of the plurality of wheels and for generating limits for the torque; and
torque distribution routine means for processing the limits with actual and intended yaw moments of the vehicle to designate the torque.
26. The system of claim 25 , the limit setting routine also receiving signals indicative of the available torque for each of the plurality of wheels.
27. The system of claim 25 , the torque distribution means distributing torque among the plurality of wheels as a function of a ratio of torque limits for each of the plurality of wheels to a sum of torque limits for the plurality of the wheels.
28. The vehicle of claim 28 , further comprising:
a plurality of wheels;
one or more torque producers for applying torque to each of the plurality of wheels;
an internal combustion engine to drive a first pair of the plurality of wheels;
one or more electric motors to drive a second pair of the plurality of wheels;
one or more sensors for determining net torque, intended yaw acceleration and actual vehicle yaw acceleration; and
means for processing data from the sensors to generate control signals to the torque producers wherein torque is distributed among the plurality of wheels with controlled traction,
the means for processing data distributing torque between the first pair and second pair being based upon one or more of a charge state of a vehicle energy storage device, a speed of the vehicle, and traction requirements.
29. The vehicle of claim 28 , the first pair of the plurality of wheels comprising friction brakes responsive to the control signals, the second pair of the plurality of wheels comprising one or both of regenerative brakes and friction brakes that are responsive to the control signals.
30. The vehicle of claim 29 , the means for processing data generating the control signals for the second pair of wheels during acceleration and generating the control signals for the first and second pairs during deceleration.
31. A system for controlling torques applied to a plurality of wheels of a motor vehicle, comprising:
one or more speed sensors for determining speed for each of the plurality of wheels;
means for determining intended vehicle direction, intended torque magnitude for the vehicle and actual yaw acceleration;
an electronic control unit for processing data from the speed sensors to generate a target yaw moment for distribution among the plurality of wheels; and
one or more torque producers, responsive to torque signals indicative of the target yaw moment to vary torque applied to each of the plurality of wheels such that the wheels engage in one of acceleration and deceleration dependent upon driver intent and with controlled traction.
32. The system of claim 31 , further comprising means for generating the target yaw moment based upon the actual yaw rate of the vehicle, the desired yaw rate of the vehicle, and the moment of inertia of the vehicle.