Method and module for controlling a vehicle's speed based on rules and/or costs

• US 9,511,668 B2
• Filed: 12/22/2011
• Issued: 12/06/2016
• Est. Priority Date: 12/22/2011
• Status: Expired due to Fees

• Current Assignee: Scania CV AB (Volkswagen AG)
• Original Assignee: Scania CV AB (Volkswagen AG)
• Inventors: Johansson, Oskar, Sdergren, Maria, Roos, Fredrik
• Primary Examiner(s): Trivedi, Atul
• Application Number:
  US14/365,361
• Publication Number:
  US 20140350820A1
• Time in Patent Office: 1,811 Days
• Field of Search: 701/93
• US Class Current: 1/1
• CPC Class Codes: B60K 2310/244 changing target speed or setting a new target speed, e.g. changing algorithms
• CPC Class Codes: B60K 31/00 Vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed, i.e. preventing speed from exceeding an arbitrarily established velocity or maintaining speed at a particular velocity, as selected by the vehicle operator fittings acting on two or more sub-units B60W30/14; speedometers G01P; systems or devices for controlling speed in general G05D13/00 ; in traffic anti-collision system for road vehicles G08G1/16
• CPC Class Codes: B60W 2050/0013 Optimal controllers
• CPC Class Codes: B60W 2552/20 Road profile, i.e. the change in elevation or curvature of a plurality of continuous road segments
• CPC Class Codes: B60W 2552/25 Road altitude
• CPC Class Codes: B60W 2556/50 of positioning data, e.g. GPS [Global Positioning System] data
• CPC Class Codes: B60W 30/143 Speed control B60W30/16 takes precedence
• CPC Class Codes: B60W 50/0097 Predicting future conditions
• CPC Class Codes: Y02T 10/84 Data processing systems or methods, management, administration

Abstract

A method for controlling a vehicle'"'"'s speed, including: acquiring a set speed; determining, using using map and location data, a horizon made of route segments, each with a route characteristic; performing simulation cycles, each including: predicting the speed according to a conventional cruise control, which first prediction depends on the route characteristic; comparing the first predicted speed with lower and upper limit values, which define an engine torque for use in the next simulation cycle; making a second prediction of the speed when the engine torque depends on the comparison in the immediately preceding simulation cycle; comparing, as a second comparison, the second predicted speed with second lower and upper limit values, which delineate a speed range within which the speed is maintained; determining, based on the second comparison and/or the second predicted speed in this simulation cycle, a reference value for use by a vehicle control system.

Claims

1. A method for controlling a speed of a vehicle based on at least one reference value, the method comprising:

acquiring a set speed for the vehicle;

determining a horizon for an itinerary of the vehicle by reference to map data and location data, which horizon comprises one or more route segments, each route segment having at least one route characteristic;

performing, by a module comprising an automated processor, a number of simulation cycles s_j, each simulation cycle comprising a number of simulation steps conducted at a predetermined rate, the simulation steps comprising;

making a first prediction of the speed of the vehicle according to a conventional cruise control when the set speed is imparted as the reference speed wherein the first prediction depends on the at least one route characteristic of said route segment;

comparing, as a first comparison, the first predicted speed with at least one of first lower and upper limit values and, wherein the first lower and upper limit values define an engine torque for use in an immediately following simulation cycle s_j+1;

making a second prediction of the speed of the vehicle, wherein an engine torque is a value which depends on a result of said first comparison in the immediately preceding simulation cycle s<sub>j−

1</sub>;

comparing, as a second comparison, the second predicted speed of the vehicle with at least one of second lower and upper limit values, wherein the second lower and upper limit values delineate a speed range within which the speed of the vehicle is maintained;

determining the at least one reference value based on said second comparison and/or the second predicted vehicle speed in this simulation cycle s_j; and

outputting to a control system of the vehicle said at least one reference value, and regulating a speed of the vehicle accordingly.

2. A method according to claim 1, wherein each of said simulation steps has a step length which depends on the speed of the vehicle.

3. A method according to claim 1, wherein said at least one reference value is at least one of the following:

a reference vehicle speed v_ref,

a reference torque T_ref, and

a reference engine speed ω

_ref.

4. A method according to claim 1, wherein the engine torque in the second prediction is a torque required to retard the vehicle below the first predicted vehicle speed in this simulation cycle s_j when this first predicted speed is determined to be above the first upper limit value in an immediately preceding simulation cycle s_j+1.

5. A method according to claim 4, wherein said at least one reference value is at least one reference value determined during a previous simulation cycle s_j−

n when the second predicted vehicle speed is below the second lower limit value in said second comparison.

6. A method according to claim 4, wherein a highest first predicted vehicle speed and a lowest first predicted vehicle speed are determined during the first prediction of the speed of the vehicle according to a conventional cruise control, which highest and lowest first predicted speeds are then used in the first comparison with the respective first lower and upper limit values to determine the engine torque T in the second prediction.

7. A method according to claim 1, wherein the engine torque in the second prediction is a torque required to accelerate the vehicle above the first predicted vehicle speed in this simulation cycle s_j when this first predicted speed is determined to be below the first lower limit value in the immediately preceding simulation cycle s_j−

1.

8. A method according to claim 7, wherein said at least one reference value is the at least one reference value determined during a previous simulation cycle s_j−

n when the second predicted vehicle speed is above the second upper limit value in said second comparison.

9. A method according to claim 1, wherein the method further comprises applying a hysteresis to said at least one reference value.

10. A method according to claim 1, wherein the method further comprises applying rules to determine the at least one reference value.

11. A method according to claim 10, wherein a rule is that the at least one reference value is the set speed when the second predicted vehicle speed in the second comparison is above the second upper limit value or below the second lower limit value.

12. A method according to claim 10, wherein the at least one reference value is the second predicted speed when both following conditions are true:

(a) a minimum value for this second predicted speed is equal to or above the second lower limit value, and

(b) a maximum value for the second predicted speed is equal to or above a further upper limit value,

wherein the further upper limit value corresponds to the set speed plus a constant.

13. A method according to claim 10, wherein the at least one reference value is the second predicted vehicle speed when both following conditions are true:

(a) a maximum value for this second predicted speed is equal to or below the upper limit value, and

(b) a minimum value for the second predicted speed is equal to or below a further lower limit value,

wherein the further lower limit value corresponds to a set speed minus a constant.

14. A method according to claim 1, wherein at least one further prediction of the speed of the vehicle is made in each simulation cycle s_j, each such further prediction of the speed of the vehicle being based on a torque which is required to raise the speed of the vehicle above the first predicted vehicle speed, or on a torque which is required to lower the speed of the vehicle below the first predicted speed, and the torque on which the at least one further prediction is based depends on said first comparison in the immediately preceding simulation cycle s_j−

1.

15. A method according to claim 14, wherein a total of three different predictions v_{pred_cc}, v_{pred_Tnew} and v_{pred_Tk+new} of the speed are made.

16. A method according to claim 1, wherein a speed profile v, energy consumption E_N and journey time t_N of the vehicle are calculated during each prediction.

17. A method according to claim 16, wherein the simulations are evaluated by calculating a cost for the second predicted vehicle speed and/or a third predicted vehicle speed.

18. A method according to claim 17, wherein the cost is calculated by employing cost functions J_Tnew and J_Tk+new for the second predicted vehicle speed and a third predicted vehicle speed, wherein the cost functions J_Tnew and J_Tk+new, respectively, use weighting with a weighting parameter β

, of energy reductions and journey time reductions relative to the first predicted speed.

19. A method according to claim 18, wherein the method further comprises:

comparing, as a fourth comparison, the cost functions J_Tnew and J_Tk+new for the second predicted vehicle speed and for a third predicted vehicle speed; and

determining based on the fourth comparison the reference value.

20. A method according to claim 16, further comprising:

adding a penalty to at least one of the cost functions J_Tnew, J_Tk+new for the second predicted vehicle speed, and for a third predicted vehicle speed, when the second and third predicted speeds reach different final speeds.

21. The method of claim 1, wherein the method is performed according to instructions incorporated on a non-transitory computer-readable medium product when the instructions are run on a processor.

22. A module arranged to control a speed of a vehicle, the module comprising:

a vehicle driver-indicated vehicle speed signal generator configured to receive a set speed for the vehicle;

a vehicle itinerary processor configured to determine an itinerary by reference to map data and location data which comprise route segments, each route segment having at least one route characteristic;

a vehicle speed simulator configured to perform a number of simulation cycles s_j, each simulation cycle including a number N of simulation steps conducted at a predetermined rate, the simulation steps comprising;

making a first prediction of the speed of the vehicle such that a set speed received for the vehicle is imparted as a reference speed, the first prediction depending on the route characteristic of said route segment;

comparing, as a first comparison, the first predicted vehicle speed with at least one of first lower and upper limit values, wherein the first lower and upper limit values define an engine torque for use in an immediately following simulation cycle s_j+1;

making a second prediction of the speed of the vehicle such that the engine torque is a value which depends on the result of said first comparison in an immediately preceding simulation cycle s<sub>j−

1</sub>;

comparing, as a second comparison, the second predicted vehicle speed with at least one of second lower and upper limit values and of the vehicle, the second lower and upper limit values delineating a range within which the speed is maintained; and

determining at least one reference value based on said second comparison and/or the second predicted vehicle speed in this simulation cycle s_j; and

a vehicle speed regulator configured to supply a control system of the vehicle with said at least one reference value for regulating the vehicle.

23. A module according to claim 22, wherein said vehicle speed simulator is configured:

to use during each simulation cycle of the N simulation steps, a constant step length, the constant step length depending on the speed of the vehicle, and

to adjust said step length based on the speed of the vehicle.

24. A module according to claim 22, wherein said at least one reference value is at least one of the following:

a reference vehicle speed v_ref

a reference torque T_ref

a reference engine speed ω

_ref.

25. A module according to claim 22, wherein the vehicle speed simulator is configured to take the engine torque in the second prediction as a torque which is required to retard the vehicle below the first predicted vehicle speed in this simulation cycle s_j, when this first predicted speed is determined to be above the first upper limit value v_lim2 in the immediately preceding simulation cycle s_j−

.

26. A module according to claim 25, wherein the vehicle speed simulator determines said at least one reference value according to the at least one reference value determined during a previous simulation cycle s_j−

n when the second predicted vehicle speed is below the second lower limit value in said second comparison.

27. A module according to claim 25, wherein the vehicle speed simulator is configured:

to determine a highest first predicted vehicle speed and a lowest first predicted vehicle speed during the first prediction of the speed according to a conventional cruise control, and

to use the highest and lowest first predicted speeds in the first comparison with the respective first lower and upper limit values and to determine the engine torque in the second prediction.

28. A module according to claim 22, wherein the vehicle speed simulator is configured to take the engine torque in the second prediction as a torque which is required to accelerate the vehicle above the first predicted vehicle speed in this simulation cycle s_j, when this first predicted speed is determined to be below the first lower limit value in the immediately preceding simulation cycle s_j−

1.

29. A module according to claim 28, wherein the vehicle speed simulator determines said at least one reference value as the at least one reference value determined during a previous simulation cycle s_j−

n when the second predicted vehicle speed is above the second upper limit value in said second comparison.

30. A module according to claim 22, wherein the vehicle speed simulator is configured to apply a hysteresis to said at least one reference value.

31. A module according to claim 22, wherein the vehicle speed simulator is configured to apply rules to determine the at least one reference value.

32. A module according to claim 31, wherein the vehicle speed simulator is configured to apply a rule that the at least one reference value is determined to a value which represents the set speed when the second vehicle predicted speed in the second comparison is above the second upper limit value or below the second lower limit value.

33. A module according to claim 31, wherein the vehicle speed simulator is configured to determine the at least one reference value to a value which represents the second predicted vehicle speed when a minimum value for this second predicted speed is equal to or above the second lower limit value, and when a maximum value for the second predicted speed is equal to or above a further upper limit value, the further upper limit value corresponding to a set speed plus a constant.

34. A module according to claim 31, wherein the vehicle speed simulator is configured to determine the at least one reference value to a value which represents the second predicted vehicle speed when a maximum value for this second predicted speed is equal to or below the upper limit value and when a minimum value for the second predicted speed is equal to or below a further lower limit value, the further lower limit value corresponding to a set speed minus a constant.

35. A module according to claim 22, wherein the vehicle speed simulator is configured to make at least one further prediction of the speed of the vehicle in each simulation cycle s_j, each such further prediction of the speed being based on a torque required to raise the speed above the first predicted speed, or based on a torque required to lower the speed below the first predicted vehicle speed, and the torque on which the at least one further first prediction is based depends on said first comparison in the immediately preceding simulation cycle s_j−

1.

36. A module according to claim 35, wherein the vehicle speed simulator is configured to make a total of three different predictions v_{pred_cc}, v_{pred_Tnew} and v_{pred_Tk+new} of the speed of the vehicle during the simulation cycle.

37. A module according to claim 22, wherein the vehicle speed simulator is configured to calculate a speed profile v, energy consumption E_N and journey time t_N of the vehicle during each prediction.

38. A module according to claim 37, wherein the vehicle speed simulator is configured to evaluate the simulations by calculating a cost for the second predicted vehicle speed and/or a third predicted vehicle speed by using at least one cost function.

39. A module according to claim 38, wherein the vehicle speed simulator is configured to determine cost functions J_Tnew and J_Tk+new for the second predicted vehicle speed and a third predicted vehicle speed by weighting using weighting parameter β

, respectively, energy reductions and journey time reductions relative to the first predicted speed.

40. A module according to claim 39, wherein the vehicle speed simulator is configured to compare, as a fourth comparison, the cost functions J_Tnew and J_Tk+new, respectively, for the second predicted vehicle speed and for a third predicted vehicle speed to determine the at least one reference value.

41. A module according to claim 37, wherein the vehicle speed simulator is configured to add a penalty to at least one of the cost functions J_Tnew, J_Tk+new, for the second predicted vehicle speed, and for a third predicted vehicle speed, when the second and third predicted speeds reach different final speeds.

42. The module of claim 22 in combination with the control system.