Method and module for controlling a vehicle's speed

• US 8,744,718 B2
• Filed: 06/21/2011
• Issued: 06/03/2014
• Est. Priority Date: 06/23/2010
• 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): Tarcza, Thomas
• Assistant Examiner(s): Lee, Tyler J
• Application Number:
  US13/806,797
• Publication Number:
  US 20130151106A1
• Time in Patent Office: 1,078 Days
• Field of Search: 701/3, 701/11, 701/23, 701/33.4, 701/48, 701 54- 68, 701/70, 701 78- 80, 701 93- 96, 701/123, 701/410, 180/170, 180 65265- 65285, 318/587, 340/988
• US Class Current: 701/93
• 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: B60K 31/0058 responsive to externally generated signalling
• CPC Class Codes: B60K 31/042 where at least one electrical quantity is set by the vehicle operator
• CPC Class Codes: B60K 31/12 including a device responsive to centrifugal forces centrifugal force acting on the vehicle due to the path it is following B60K31/0083, motor speed limiting by governors G05D13/10
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 2510/0657 Engine torque
• CPC Class Codes: B60W 2552/15 Road slope, i.e. the inclination of a road segment in the longitudinal direction
• 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 2556/50 of positioning data, e.g. GPS [Global Positioning System] data
• CPC Class Codes: B60W 2710/0666 Engine torque
• CPC Class Codes: B60W 2720/103 Speed profile
• CPC Class Codes: B60W 30/143 Speed control B60W30/16 takes precedence
• CPC Class Codes: B60W 50/0097 Predicting future conditions
• CPC Class Codes: B60W 50/087 where the control system corrects or modifies a request from the driver
• CPC Class Codes: G08G 1/123 indicating the position of vehicles, e.g. scheduled vehicles; Managing passenger vehicles circulating according to a fixed timetable, e.g. buses, trains, tramstransmission of navigation instructions to vehicles G08G1/0968
• CPC Class Codes: Y02T 10/84 Data processing systems or methods, management, administration

Abstract

A method for controlling a vehicle'"'"'s speed includes adopting a desired speed v_set for the vehicle; determining by means of map data and location data a horizon for the intended itinerary which is made up of route segments with at least one characteristic for each segment; effecting the following during each of a number of simulation cycles (s) each comprising a number N of simulation steps conducted at a predetermined frequency f: making a first prediction of the vehicle'"'"'s speed v_pred—cc along the horizon with conventional cruise control when v_set is presented as reference speed, which prediction depends on the characteristics of said segment; comparing the predicted vehicle speed v_pred—cc with v_min and v_max, which demarcate a range within which the vehicle'"'"'s speed is intended to be; making a second prediction of the vehicle'"'"'s speed v_pred—Tnew along the horizon when the vehicle'"'"'s engine torque T is a value which depends on the result of said comparison in the latest preceding simulation cycle (s−1); determining at least one reference value for how the vehicle'"'"'s speed is to be influenced on the basis of at least one of said comparisons in that simulation cycle (s) and the predicted vehicle speed v_pred—Tnew; sending to a control system in the vehicle said at least one reference value with respect to which the vehicle is thereupon regulated. The invention comprises also a module for controlling a vehicle'"'"'s speed.

Claims

1. A method for controlling a vehicle'"'"'s speed, performed by a control unit on a vehicle, the method comprises:

adopting a desired speed v_set for the vehicle;

determining by means of map data and location data a horizon for an intended itinerary which is made up of route segments with at least one characteristic for each segment;

effecting the following during each of a number of simulation cycles (s) each comprising a number N of simulation steps conducted at a predetermined frequency f;

making a first prediction of the vehicle'"'"'s speed v<sub>pred—

cc</sub> along the horizon with conventional cruise control when v_set is presented as reference speed, which prediction depends on the characteristics of said segment;

comparing the first predicted vehicle speed v<sub>pred—

cc</sub> with v_min and v_max, which demarcate an intended range for the vehicle'"'"'s speed;

making a second prediction of the vehicle'"'"'s speed v<sub>pred—

Tnew</sub> along the horizon when the vehicle'"'"'s engine torque T is a value which depends on the result of the comparison in a latest preceding simulation cycle (s−

1);

making in each simulation cycle a third prediction of the vehicle'"'"'s speed v<sub>pred—

Tk+new</sub> along the horizon with ordinary cruise control and thereafter when the vehicle'"'"'s engine torque T is replaced by a maximum torque or a minimum torque depending on said comparison;

determining at least one reference value which indicates how the vehicle'"'"'s speed is to be influenced on the basis of at least one of the comparisons in that simulation cycle (s) and the predicted vehicle speed v<sub>pred—

Tnew</sub>; and

sending to a control system in the vehicle the at least one reference value with respect to which the vehicle is thereupon regulated.

2. A method according to claim 1, further comprising performing a series of N of the simulation steps to define a cycle of the simulation steps, and the simulation steps during a simulation cycle of N said simulation steps have a constant step length which depends on the vehicle'"'"'s speed.

3. A method according to claim 1, wherein the reference value is selected from among a reference vehicle speed v_ref, a reference torque T_ref or a reference engine speed ω

_ref.

4. A method according to claim 1, further comprising performing a series of N of the simulation steps to define a cycle of the simulation steps, and wherein if v_pred—

_cc is higher than v_max, the vehicle'"'"'s engine torque T in the second prediction is taken as a minimum torque in subsequent simulation cycles.

5. A method according to claim 1, further comprising performing a series of N of the simulation steps to define a cycle of the simulation steps, and wherein if v_pred—

_cc is lower than v_min the vehicle'"'"'s engine torque T in the second prediction, taking that torque is taken as a maximum torque in subsequent simulation cycles.

6. A method according to claim 5, further comprising detecting the highest speed v_pred—

_cc,max and the lowest speed v<sub>pred—

cc,min</sub> during the second prediction of the vehicle'"'"'s speed v<sub>pred—

cc</sub> with ordinary cruise control and are then using v<sub>pred—

cc,max</sub> in the comparison with v_max and v_min to determine the vehicle'"'"'s engine torque T in the second prediction.

7. A method according to claim 1, further comprising adding a hysteresis to v_ref.

8. A method according to claim 1, further comprising calculating during each prediction the vehicle'"'"'s speed profile (v), energy consumption (E) and run time (t).

9. A method according to claim 8, further comprising evaluating the simulations by calculating the cost for the predicted driving modes by means of at least one cost function J_Tnew, J_Tk+new.

10. A method according to claim 9, further comprising predicting costs J_Tnew and J_Tk+new for driving modes according to the second and third predictions by applying a weighting parameter β

to their energy reduction and run time reduction compared with the driving mode according to the first prediction.

11. A method according to claim 10, which comprises comparing the costs J_Tnew and J_Tk+new and determining on the basis of the comparison a reference value with respect to which the vehicle is to be regulated.

12. A method according to claim 9, further comprising adding a penalty to at least one cost function on the basis of the vehicle in the predictions not reaching the same final speed.

25. A computer programme product pertaining to controlling a vehicle'"'"'s speed wherein said programme product comprises non-transitory programme code with non-transitory programme instructions for causing a computer system to perform steps according to claim 1 in a vehicle when the instructions in said code are run on said computer.

26. A computer programme product according to claim 25, wherein said product contains a programme code stored on a non-transitory computer-readable medium which can be read by said computer system for performing method steps when said computer programme is run on electronic control unit or another computer connected to said electronic control unit.

13. A module for controlling a vehicle'"'"'s speed, performed by a control unit on a vehicle comprises:

an input unit configured for receiving a desired speed v_set for the vehicle;

a horizon unit configured for determining by means of map data and location data a horizon for an intended itinerary which is comprised of route segments with at least one characteristic for each segment;

a calculation unit configured for effecting the following during each of a number of simulation cycles (s) wherein each cycle comprises a number N of simulation steps conducted at a predetermined frequency f, the steps each comprising;

making a first prediction of the vehicle'"'"'s speed v<sub>pred—

cc</sub> along a horizon with a conventional cruise control when v_set is presented as a reference speed, wherein the prediction depends on the characteristics of the segment;

comparing the first prediction of vehicle speed v<sub>pred—

cc</sub> with v_min and v_max, which demarcate a range of the vehicle'"'"'s intended speed;

making a second prediction of the vehicle'"'"'s speed v<sub>pred—

Tnew</sub> along the horizon when the vehicle has an engine torque T having a value which depends on a result of the comparison in the latest preceding simulation cycle (s−

1);

making in each simulation cycle of N simulation steps a third prediction of the vehicle'"'"'s speed v<sub>pred—

Tk+new</sub> along the horizon when the prediction is first made with conventional cruise control and thereafter when the vehicle'"'"'s engine torque T is replaced by a maximum torque or a minimum torque depending on said comparison;

determining at least one reference value which indicates how the vehicle'"'"'s speed is to be influenced on the basis of at least one of the comparisons in that simulation cycle (s) and the predicted vehicle speed v<sub>pred—

Tnew</sub>; and

the module is further configured for sending to a control system in the vehicle said at least one reference value with respect to which the vehicle is thereupon regulated.

14. A module according to claim 13, wherein the simulation steps during a simulation cycle of N simulation steps have a constant step length which depends on the vehicle'"'"'s speed, and the calculation unit is configured for adjusting the step length according to the vehicle'"'"'s speed.

15. A module according to claim 13, wherein the reference value is selected from among a reference vehicle speed v_ref, a reference torque T_ref or a reference engine speed ω

_ref.

16. A module according to claim 13, wherein the calculation unit is configured for calculating if v_pred—

_cc is higher than or equal to v_max, and then is configured for taking the vehicle'"'"'s engine torque T in the second prediction as a minimum torque in subsequent simulation cycles.

17. A module according to claim 13, wherein the calculation unit is configured for calculating if v_pred—

_cc is lower than or equal to v_min and is configured for then taking the vehicle'"'"'s engine torque T in the second prediction as a maximum torque in subsequent simulation cycles.

18. A module according to claim 16, wherein the calculation unit is configured for determining the highest speed v_pred—

_cc,max and the lowest speeds v<sub>pred—

cc,min</sub> during the first prediction of the vehicle'"'"'s speed v_cc with ordinary cruise control, and to using said v<sub>pred—

cc,max</sub> and v<sub>pred—

cc,min</sub> in the comparison with v_max and v_min to determine the vehicle'"'"'s engine torque T in the second prediction.

19. A module according to claim 13, wherein the calculation unit is configured for adding a hysteresis to v_ref.

20. A module according to claim 13, wherein the calculation unit is configured for calculating during each prediction the vehicle'"'"'s speed profile (v), energy consumption (E) and run time (t).

21. A module according to claim 20, wherein the calculation unit is configured for evaluating the simulations by calculating the cost for the predicted driving modes by means of at least one cost function J_Tnew, J_Tk+new.

22. A module according to claim 21, wherein the calculation unit is configured for determining the costs modes J_Tnew and J_Tk+new for driving modes according to the second and third predictions by applying a weighting parameter β

to their energy reduction and run time reduction compared with a driving mode according to the first prediction.

23. A module according to claim 20, wherein the calculation unit is configured for comparing the costs J_Tnew and J_Tk+new and determining on the basis of the comparison the reference value v_ref with respect to which the vehicle is to be regulated.

24. A module according to claim 20, wherein the calculation unit is configured for adding a penalty to at least one cost function on the basis of the vehicle in the predictions not reaching the same final speed.