Systems and methods for electric vehicle speed control
Example methods and systems for controlling speeds of a vehicle may generally determine a target vehicle acceleration using an autonomy control module of the vehicle. The target vehicle acceleration may be determined based upon at least one of a target vehicle following distance, a target vehicle following speed, or a target vehicle speed. The determined vehicle acceleration may be mapped to a level of vehicle torque using a vehicle dynamics module of the vehicle. Additionally, the level of vehicle torque may be applied to one or more wheels of the vehicle.
1. A speed control system for controlling speed of a vehicle, the system comprising:
an autonomy control processing circuitry module of the vehicle, the autonomy control processing circuitry module configured to:
determine a target vehicle acceleration based upon at least one of a target vehicle following distance, a target vehicle following speed, or a target vehicle speed,
wherein the autonomy control processing circuitry module may be applied to more than one vehicle type; and
a vehicle dynamics processing circuitry module of the vehicle configured to:
map the determined target vehicle acceleration to a level of vehicle torque; and
output the level of vehicle torque to be applied to one or more wheels of the vehicle, wherein:
the level of vehicle torque is applied as an input to a drive unit;
the drive unit generates and applies the level of vehicle torque to the one or more wheels; and
the vehicle dynamics processing circuitry module is tailored to the vehicle type of the vehicle.
2. The system of claim 1 , wherein the vehicle dynamics processing circuitry module is configured to map the determined target vehicle acceleration to the level of vehicle torque based on a vehicle speed.
3. The system of claim 2 , wherein the vehicle dynamics processing circuitry module is configured to map the determined target vehicle acceleration to the level of vehicle torque by determining a plurality of constants, multiplying each of the plurality of constants by a respective vehicle speed term to determine a plurality of products, and adding the sum of the products.
4. The system of claim 3 , wherein the plurality of constants are determined from at least a coast-down of the vehicle.
5. The system of claim 3 , wherein the sum of the products represents a road load of the vehicle as a function of vehicle speed.
6. The system of claim 1 , wherein the vehicle dynamics processing circuitry module is configured to apply the level of vehicle torque by adjusting vehicle torque over time to reach the one of the target vehicle following distance, the target vehicle following speed, or the target vehicle speed.
7. The system of claim 1 , wherein the autonomy control processing circuitry module is configured to:
compare actual acceleration of the vehicle to the determined target vehicle acceleration; and
adjust the mapping based on the comparison.
8. The system of claim 1 , wherein the autonomy control processing circuitry module is configured to determine the one of the target vehicle following distance, the target vehicle following speed, or the target vehicle speed based upon an input received from an operator input interface indicative of the target vehicle following distance, the target vehicle following speed, or the target vehicle speed, respectively.
9. A modular autonomy control module for use in one or more types of vehicles, wherein the modular autonomy control module is configured to:
detect one or more sensor inputs;
determine at least one of a target vehicle following distance, a target vehicle following speed, or a target vehicle speed based at least on the one or more sensor inputs;
determine a target vehicle acceleration based on the at least one of the target vehicle following distance, the target vehicle following speed, or the target vehicle speed; and
output the target vehicle acceleration to a vehicle dynamics module that is tailored to a vehicle type of a vehicle, wherein:
the vehicle dynamics module is configured to, for the vehicle type of the vehicle, convert the target vehicle acceleration to a corresponding torque request to achieve the target vehicle acceleration;
the vehicle dynamics module outputs the corresponding torque request to be applied to one or more wheels;
the corresponding torque request is applied as an input to a drive unit;
the drive unit generates and applies the corresponding torque request to the one or more wheels; and
the modular autonomy control module may be applied to more than one vehicle type.
10. A method of controlling speed of a vehicle, the method comprising:
determining a target vehicle acceleration, using an autonomy control module of the vehicle, based upon inputs to the autonomy control module including at least one of a target vehicle following distance, a target vehicle following speed, or a target vehicle speed, wherein the autonomy control module may be applied to more than one vehicle type;
mapping the determined target vehicle acceleration to a level of vehicle torque using a vehicle dynamics module of the vehicle, based upon vehicle dynamics module inputs including at least the determined target vehicle acceleration; and
applying the level of vehicle torque to one or more wheels of the vehicle, wherein:
the level of vehicle torque is applied as an input to a drive unit;
the drive unit generates and applies the level of vehicle torque to the one or more wheels; and
the vehicle dynamics module is tailored to the vehicle type of the vehicle.
11. The method of claim 10 , further comprising:
determining one or more speeds of the vehicle, wherein the determined target vehicle acceleration is mapped to the level of vehicle torque based on the one or more determined speeds of the vehicle.
12. The method of claim 11 , wherein mapping the determined target vehicle acceleration to the level of vehicle torque includes:
determining a plurality of constants;
multiplying each of the plurality of constants by a respective vehicle speed term to determine a plurality of products; and
adding the sum of the products.
13. The method of claim 12 , wherein the plurality of constants are determined from at least a coast-down of the vehicle, and wherein the sum of the products represents a road load of the vehicle as a function of vehicle speed.
14. The method of claim 10 , further comprising:
determining, using the autonomy control module, at least one of the target vehicle speed or a target vehicle direction; and
autonomously implementing, using the autonomy control module, at least one of a vehicle speed change or a vehicle direction change.
15. The method of claim 10 , further comprising:
determining a time period to reach the determined target vehicle acceleration, and wherein applying the level of vehicle torque comprises adjusting the level of vehicle torque over the time period to reach target levels of vehicle torque for each of the one or more wheels of the vehicle.
16. The method of claim 10 , further comprising:
comparing actual acceleration of the vehicle to the determined target vehicle acceleration; and
adjusting the mapping based on the comparison, wherein the adjusted mapping indicates a second level of vehicle torque based at least on the comparison with the actual acceleration and the determined target vehicle acceleration; and
applying the second level of vehicle torque to the one or more wheels of the vehicle.
17. The method of claim 10 , further comprising:
determining the level of vehicle torque is a braking torque comprising a current regenerative torque for a battery system of the vehicle; and
in response to determining the level of vehicle torque is less than the current regenerative torque, applying the level of vehicle torque with the current regenerative torque via one or more electric motors of the vehicle, wherein each of the one or more electric motors independently control the one or more wheels of the vehicle.
18. The method of claim 10 , further comprising:
determining the level of vehicle torque is a braking torque that is greater than a current regenerative torque for a battery system of the vehicle; and
in response to determining the level of vehicle torque is greater than a current regenerative torque capability, applying the level of vehicle torque with one or more mechanical wheel brakes to an extent the level of vehicle torque exceeds the current regenerative torque.
19. The method of claim 10 , wherein applying the level of vehicle torque to the one or more wheels of the vehicle includes applying regenerative torque braking and mechanical braking when the level of vehicle torque exceeds a current regenerative torque of a vehicle battery system.