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EP-4536523-B1 - SAFE OPERATION OF VEHICLE COMBINATIONS

EP4536523B1EP 4536523 B1EP4536523 B1EP 4536523B1EP-4536523-B1

Inventors

  • ANDERSSON, ERIK
  • HANSSON, Axel
  • LAINE, LEO
  • SADEGHI KATI, Maliheh
  • ERDINC, UMUR
  • JONASSON, MATS
  • VILCA, José

Dates

Publication Date
20260513
Application Date
20220606

Claims (17)

  1. A computer-implemented method (100) of determining a torque limit for an operating state of a first vehicle combination (10), the vehicle combination comprising a tractor unit (12) and at least one trailing unit (14), the method comprising: simulating (102) a plurality of operating states for one or more second vehicle combinations (10), wherein each operating state is based on: one or more operational parameters related to physical properties of the one or more second vehicle combinations (10), one or more parameters related to an operating environment of the one or more second vehicle combinations (10), and one or more parameters related to a driving scenario of the one or more second vehicle combinations (10); classifying (104) each of the simulated operating states as safe or unsafe; receiving (106) an unsimulated operating state for the first vehicle combination (10); and determining (108) a torque limit for the unsimulated operating state based on the simulated operating states.
  2. The computer-implemented (100) method of claim 1, wherein simulating (102) a plurality of operating states comprises using a non-linear high fidelity mathematical transport model.
  3. The computer-implemented method (100) of claim 1 or 2, wherein the one or more operational parameters related to physical properties of a particular second vehicle combination (10) comprises at least one of a geometry of the second vehicle combination (10), a number of axles (16, 20) of the tractor unit (12), a distance between the axles (16, 20) of the tractor unit (12), a number of axles (18, 22) of the at least one trailing unit (14), a distance between the axles (18, 22) of the at least one trailing unit (14), a number of motion support devices of the tractor unit (12), a number of motion support devices of the at least one trailing unit (14), a cornering stiffness on the tyres of the tractor unit (12), a cornering stiffness on the tyres of the at least one trailing unit (14), an inertia about a yaw-axis of the tractor unit (12), an inertia about a yaw-axis of the at least one trailing unit (14), an electric motor peak torque output on the tractor unit (12), an electric motor peak torque output on the at least one trailing unit (14), an axle load on at least one axle (16, 20) of the tractor unit (12), and an axle load on at least one axle (18, 22) of the at least one trailing unit (14).
  4. The computer-implemented method (100) of any preceding claim, wherein the one or more parameters related to an operating environment of a particular second vehicle combination (10) comprises at least one of a road profile and a road surface friction coefficient.
  5. The computer-implemented method (100) of any preceding claim, wherein the one or more parameters related to a driving scenario of a particular second vehicle combination (10) comprises at least one of a longitudinal speed of the tractor unit (12), at least one articulation angle between consecutive units, a total applied torque on the tractor unit (12), a total applied torque on the at least one trailing unit (14), a longitudinal coupling force at each coupling point, a lateral coupling force at each coupling point.
  6. The computer-implemented method (100) of any preceding claim, wherein classifying (104) each of the simulated operating states as safe or unsafe comprises determining an outcome of a driving manoeuvre defined by the operating state.
  7. The computer-implemented method (100) of claim 6, comprising classifying the operating state as unsafe if the outcome of the driving manoeuvre is an unsafe mode comprising at least one of: off-tracking of the vehicle combination (10), jack-knifing of the vehicle combination (10), swing of the at least one trailing unit (14), or rollover of the vehicle combination (10).
  8. The computer-implemented method (100) of claim 6 or 7, comprising classifying the operating state as safe if the outcome of the driving manoeuvre is not an unsafe mode.
  9. The computer-implemented method (100) of any preceding claim, comprising determining a torque limit for the plurality of operating states of the second vehicle combinations (10) to provide a safe operating envelope for the second vehicle combinations (10).
  10. The computer-implemented method (100) of any preceding claim, further comprising validating the determined torque limits using data from real life driving of the second vehicle combinations (10).
  11. The computer-implemented method (100) of any preceding claim, wherein receiving (106) the unsimulated operating state for the first vehicle combination (10) comprises receiving an operating state for an unsimulated vehicle combination (10) and/or receiving an unsimulated operating state for a simulated vehicle combination (10).
  12. The computer-implemented method (100) of any preceding claim, wherein the unsimulated operating state comprises at least one of a road surface friction coefficient, a longitudinal speed of the tractor unit (12), an articulation angle between consecutive units, a total applied torque on the tractor unit (12), a total applied torque on the at least one trailing unit (14), a longitudinal coupling force at each coupling point, and a lateral coupling force at each coupling point for the unsimulated operating state.
  13. The computer-implemented method (100) of any preceding claim, wherein determining (108) the torque limit for the unsimulated operating state comprises determining a nearest simulated operating state.
  14. The computer-implemented method (100) of any preceding claim, wherein determining (108) the torque limit for an unsimulated vehicle combination (10) comprises interpolating between operating states of two similar simulated vehicle combinations (10).
  15. The computer-implemented method (100) of any preceding claim, further comprising applying the determined torque limit to a total propulsion load of a plurality of motion support devices of the tractor unit (12) and/or the at least one trailing unit (14).
  16. The computer-implemented method (100) of claim 15, wherein the plurality of motion support devices comprises a plurality of electric motors.
  17. A computer-readable medium having stored thereon instructions that, when executed by one or more processors cause execution of the method steps according to any of claims 1 to 16.

Description

FIELD This disclosure relates to safe operation of vehicle combinations. In particular, it relates to determining torque limits for combinations of at least two vehicle units in different operating states. BACKGROUND The total global carbon emissions footprint of humans has increased exponentially over the past decades. It is expected to keep increasing in the years to come. In 2020, the road transport sector, which includes heavy-duty trucks used in, for instance, construction, logging and refrigeration, were estimated to account for 5% of total global CO2 emissions and 30% of global CO2 emissions in the transport sector. As such, research of battery electric vehicles (BEVs) is a popular topic in the heavy vehicle industry, as they serve as an environmentally sustainable alternative to combustion engines that run on fossil fuels. Several companies in the heavy truck industry aim to reach a point in the near future where they only sell and produce trucks that use electrical power as the main source of propulsion. One of the many issues with battery operated heavy trucks is their ability to maintain as long a range as their fossil fuel powered counterparts. Current BEV trucks are able to achieve ranges that are adequate for short haul transportation in urban areas like cities and industrial areas. However, for long haul transportation, existing electric trucks may require numerous time consuming recharges to complete an entire journey. One solution to extend the range of a vehicle is to add more batteries, thus increasing the total on-board energy capacity. If batteries are installed in the trailer of a tractor semi-trailer combination, electrical motors may also be installed so that the trailer can be used as a propulsive complement to the vehicle. This allows for the possibility of using an electric trailer on both tractors with internal combustion engines and on BEV-tractors. Furthermore, conventional heavy truck 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. However, introducing propulsive elements to a trailer will affect the stability of a vehicle combination in certain operating states when compared to the more traditional setup where only the tractor is pulling the vehicle combination. Therefore, further knowledge is required to understand whether safe driving can be ensured when a trailer is accelerating or retarding a vehicle combination. US 2021/394758 A1 discloses an apparatus and method for controlling articulation of an articulated vehicle. The apparatus includes a hitch angle calculator configured to calculate a desired hitch angle based on a steering angle and a speed of the articulated vehicle, an error calculator configured to calculate an error between the desired hitch angle and an actual hitch angle of the articulated vehicle, a moment generator configured to generate a moment for controlling the articulation of the articulated vehicle based on the error, and an articulation controller configured to control the articulation of the articulated vehicle based on the moment. SUMMARY This disclosure attempts to solve the problems noted above by providing methods to determine how to use an electric trailer for propulsion in a vehicle combination in a safe manner. The disclosure is focused on using multi-unit vehicle combinations where different units can be used as propulsion units. This enables unconventional propulsion strategies to be analysed, for example, a vehicle combination propelled only by the batteries and electric motors of an electric trailer. Safe driving is defined as when a vehicle combination is not in any of a predetermined set of unsafe modes. A set of requested forces and moments (from the physical driver or autonomous system) together with additional parameters such as road profile and longitudinal speed of the vehicle can then be used to determine a safe operating envelope (SOE) for the vehicle combination. SOEs have been well studied in the flight industry. However, they are limited in the sphere of heavy vehicles. This disclosure uses parameters of operating states of vehicle combinations to determine which user inputs will yield safe vehicle motion and which will not. This can be defined by torque limits that ensure safe driving in different operating states. This enables the use of electric trailers for propulsion to increase the range of BEV trucks, while ensuring unsafe vehicle behaviour can be avoided during normal driving conditions. According to an aspect, there is provided a computer-implemented method of determining a torque limit for an operating state of a first vehicle combination, the vehicle combination comprising a tractor unit and at least one trailing unit, the method comprising simulating a plurality of operating states for one or more sec