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EP-4536525-B1 - METHOD OF CONTROL ALLOCATION FOR MULTI-UNIT VEHICLE COMBINATIONS

EP4536525B1EP 4536525 B1EP4536525 B1EP 4536525B1EP-4536525-B1

Inventors

  • SADEGHI KATI, Maliheh
  • GELSO, Esteban
  • LAINE, LEO

Dates

Publication Date
20260506
Application Date
20221117

Claims (17)

  1. A computer-implemented method (400) for controlling a vehicle combination (100) comprising a tractor unit and at least one trailing unit, the method comprising: determining (406) a power allocation input, u units,des , for the vehicle combination based on a reference input, r ref , for the vehicle combination and a power capability of one or more units (110) of the vehicle combination such that the total power losses of the vehicle combination are below a threshold; determining (410) a virtual control input, v comb,req , for the vehicle combination based on the reference input; and determining (412, 414, 416) a control input, u units , u units,i , ui, for the vehicle combination based on the power allocation input and the virtual control input.
  2. The computer-implemented method (400) of claim 1, wherein the virtual combination control input, v comb,req , comprises a set of desired motion parameters determined based the reference input, r ref , .
  3. The computer-implemented method (400) of claim 2, wherein the set of desired motion parameters of the virtual combination control input, v comb,req , comprises at least one of a longitudinal force, F xtot , of the vehicle combination (100), a lateral force, F ytot , of the vehicle combination, a longitudinal coupling force, F cxi , between consecutive units (110), a lateral coupling force, F cyi , between consecutive units, and a yaw moment for one or more units, M zi .
  4. The computer-implemented method (400) of any preceding claim, comprising determining (410) the virtual control input, v comb,req , for the vehicle combination (100) based on a motion capability, v comb,cap , of the vehicle combination.
  5. The computer-implemented method (400) of any preceding claim, comprising determining (410) the virtual control input, v comb,req , for the vehicle combination (100) based on a vehicle model configured to model instabilities in vehicle motion.
  6. The computer-implemented method (400) of any preceding claim, wherein the reference input, r ref , comprises at least one of a longitudinal acceleration, a longitudinal velocity, v xi , of the tractor unit, a lateral velocity, v yi , of the tractor unit, a yaw rate, ω zi , of at least one unit (110) of the vehicle combination (100), and a steering angle, δ f,req , of the tractor unit.
  7. The computer-implemented method (400) of any preceding claim, wherein the power capability of a unit (110) is determined based on at least one of a state of charge, a state of health, a state of power, and a state of energy of a battery of the unit.
  8. The computer-implemented method (400) of any preceding claim, wherein the power allocation input, u units,des , comprises a set of desired motion parameters determined based on a power allocation for one or more units (110).
  9. The computer-implemented method (400) of claim 8, wherein the set of desired motion parameters of the power allocation input, u units,des , comprises at least one of a desired electric machine force, F x,eli,des , for one or more units and a desired electric service brake, F x,sbi,des , force for one or more units (110).
  10. The computer-implemented method (400) of claim 8 or 9, comprising determining (406) the power allocation for a unit (110) based on a power demand and at least one of a power loss associated with service brakes (150) of the unit, a power loss associated with a battery (120) of the unit, and a power loss associated with an electrical machine (120) of the unit.
  11. The computer-implemented method (400) of claim 10, comprising determining (406) the power allocation for one or more units (110) using an optimisation function to minimise the total power losses of the vehicle combination (100).
  12. The computer-implemented method (400) of any preceding claim, comprising determining (412, 414, 416) a control input, u units , u units,i , ui, for the vehicle combination (100) by: determining (412) a true combination control input, u units , based on the power allocation input, u units,des , and the virtual combination control input, v comb,req ; and determining (414) a unit-specific virtual control input, u units,i , based on the true combination control input.
  13. The computer-implemented method (400) of claim 12, comprising determining (412) the true combination control input, u units , by solving a weighted least squares optimization problem.
  14. The computer-implemented method (400) of claim 12 or 13, comprising determining (416) a unit-specific true control input, u i , for a respective unit (110) of the vehicle combination (100) based on the unit-specific virtual control input, u units,i .
  15. The computer-implemented method (400) of claim 14, comprising determining (416) the unit-specific true control input, u i , by solving a weighted least squares optimization problem.
  16. A computer system comprising a processor device configured to perform the computer-implemented method (400) of any of claims 1 to 15.
  17. A vehicle comprising the system of claim 16.

Description

TECHNICAL FIELD The invention relates generally to control allocation for a vehicle combination. In particular aspects, the invention relates to a system and method for determining a control input for one or more units of a vehicle combination having multiple units. The invention can be applied in heavy-duty vehicles, such as trucks, buses, and construction equipment. In particular, the invention can be applied in multi-unit vehicle combinations with distributed propulsion and energy storage. Although the invention may be described with respect to a particular vehicle, the invention is not restricted to any particular vehicle. BACKGROUND In traditional vehicle combinations, for example semi-trailers, a tractor unit may provide propulsion for the entire combination, while trailer units are towed behind. Traditional vehicle combinations may employ internal combustion engines in a tractor unit to provide propulsion. In battery electric vehicle combinations, batteries may be installed in the tractor unit to power electric motors and provide propulsion. If batteries are also installed in the trailer of a vehicle combination, electrical motors may also be installed so that the trailer can be used as a propulsive complement to the combination. This allows for the possibility of using an electric trailer on both tractors with internal combustion engines and on battery electric vehicle tractors. Furthermore, conventional heavy vehicle trailers are normally installed with pneumatic brakes to make the vehicle stop safely and in time. An electric trailer could also be used to recharge the batteries through regenerative braking, thus preventing wasting energy through the mechanical braking system. As vehicle combinations become more and more complex, the increasing number of controllable degrees of freedom makes it challenging to control the vehicle combination as a whole. In particular, as the number of controllable degrees of freedom starts to exceed the number of desired forces and moments of the vehicle combination as a whole, the vehicle combination becomes over-actuated, and the problem of control becomes underdetermined. As a result, there can be multiple possible solutions for how to control the various actuators such that they together generate the desired overall forces and moments. So-called control allocation is often used to address this problem, wherein a control allocator receives desired forces and moments for the vehicle combination as a whole (a so-called virtual control input), and attempts to solve an optimization problem in order to find an optimal solution for how the actuators should be controlled (a so-called true control input). Conventional control allocators are often responsible for directly controlling the actuators in all vehicle units, and are often tailored specifically to a particular configuration of the vehicle combination due to the complexity of the problem they are supposed to solve. Solutions that approach the problem on a unit level do not take into account global factors for the vehicle combination. It is therefore desired to develop a solution for control allocation for vehicle combinations that addresses or at least mitigates some of these issues. US 2022/0097786 Al discloses a method for controlling, via a trailer vehicle configured to be coupled to a towing vehicle with an electric drive, the electric drive of the towing vehicle includes receiving, via a trailer brake control unit of the trailer vehicle, a current accelerator pedal position from the towing vehicle. The method further includes generating a control signal for the electric drive with the trailer brake control unit depending on the received current accelerator pedal position and controlling the electric drive with the generated control signal. "Real-time Performance of Control Allocation for Actuator Coordination in Heavy Vehicles" by K Tagesson et al, Intelligent Vehicles Symposium, IEEE, Piscataway, NJ, USA, 3 June 2009, discloses a basic stability control system implementing a method in which the real-time performance of two different control allocation solvers is evaluated and the use of dynamic weighting is analysed. WO 2022/106005 Al discloses method for reducing off-tracking by a multi-trailer heavy duty vehicle during a manoeuvre, the method comprising obtaining a model of vehicle dynamics describing dynamics of the multi-trailer heavy duty vehicle, determining respective force trajectories for two or more axles of the vehicle as a solution to a non-linear optimal control problem, and controlling motion of the heavy duty vehicle during the manoeuvre based on the determined force trajectories. SUMMARY The invention attempts to solve the problems noted above by providing methods and systems for controlling multi-unit vehicle combinations with distributed propulsion and energy storage. In particular, a system is implemented which takes into account power management and generation of target motion parameters