US-12623555-B2 - Computer system and a method for controlling an electric propulsion system of an autonomous working machine

US12623555B2US 12623555 B2US12623555 B2US 12623555B2US-12623555-B2

Abstract

A computer system and a method for control of an electric propulsion system of an autonomous working machine including a first axle and a second axle, the electric propulsion system including a first electric system configured to drive the first axle, including a first electric energy storage system, and a second electric system configured to drive the second axle, including a second electric energy storage system. The method includes determining a longitudinal gradient along an expected travelling path, determining charge levels of the first and second electric energy storage systems, respectively, and controlling the working machine to assume a first orientation or a second orientation to travel along the expected travelling path, wherein the orientation of the working machine is controlled in dependence on the determined longitudinal gradient and the determined charge levels.

Inventors

Christian Ohlin
Per Mattsson

Assignees

VOLVO CONSTRUCTION EQUIPMENT AB

Dates

Publication Date: 20260512
Application Date: 20240626
Priority Date: 20230707

Claims (15)

1 . A computer system comprising processing circuitry configured to control an electric propulsion system of an autonomous working machine comprising a first axle located near a first end of the working machine and a second axle located near a second end of the working machine, the electric propulsion system comprising: a first electric system configured to drive the first axle, the first electric system comprising a first electric energy storage system and a first electric motor, and a second electric system configured to drive the second axle, the second electric system comprising a second electric energy storage system and a second electric motor, the processing circuitry being configured to: determine a longitudinal gradient along an expected travelling path of the working machine, determine charge levels of the first and second electric energy storage systems, respectively, and control the working machine to assume a first orientation or a second orientation to travel along the expected travelling path, the first end of the working machine being a leading end in the first orientation, and the second end of the working machine being a leading end in the second orientation, wherein the orientation of the working machine is controlled in dependence on the determined longitudinal gradient and the determined charge levels.
2 . The computer system of claim 1 , wherein the processing circuitry is further configured to: detect an uphill road segment along the expected travelling path, in response to determining that the charge level of the first electric energy storage system exceeds the charge level of the second electric energy storage system by at least a first threshold amount, control the working machine to assume the second orientation prior to entering the detected uphill road segment, and in response to determining that the charge level of the second electric energy storage system exceeds the charge level of the first electric energy storage system by at least the first threshold amount, control the working machine to assume the first orientation prior to entering the detected uphill road segment.
3 . The computer system of claim 2 , wherein the uphill road segment is a road segment over which a vertical height increases by at least a first threshold height.
4 . The computer system of claim 3 , wherein the first threshold height is set in dependence on a working machine weight in such a way that it decreases with increasing working machine weight.
5 . The computer system of claim 1 , wherein the processing circuitry is configured to: detect a downhill road segment along the expected travelling path, in response to determining that the charge level of the first electric energy storage system exceeds the charge level of the second electric energy storage system by at least a second threshold amount, control the working machine to assume the second orientation prior to entering the detected downhill road segment, and in response to determining that the charge level of the second electric energy storage system exceeds the charge level of the first electric energy storage system by at least the second threshold amount, control the working machine to assume the first orientation prior to entering the detected downhill road segment.
6 . The computer system of claim 5 , wherein the downhill road segment is a road segment over which a vertical height decreases by at least a second threshold height, wherein the second threshold height is set in dependence on a working machine weight in such a way that it decreases with increasing working machine weight.
7 . The computer system of claim 5 , wherein the processing circuitry is further configured to: assess whether a predetermined condition for allowing the working machine to travel through the downhill road segment in the second orientation is fulfilled, wherein the processing circuitry is only configured to control the working machine to assume the second orientation if the predetermined condition is fulfilled.
8 . The computer system of claim 7 , wherein the predetermined condition is related to a working machine weight and/or to the longitudinal gradient within the downhill road segment.
9 . The computer system of claim 7 , wherein the predetermined condition is considered fulfilled when the longitudinal gradient within the downhill road segment is lower than a threshold gradient, and/or when the longitudinal gradient is not expected to result in a working machine inclination above a threshold inclination, and/or when the working machine weight is below a threshold weight.
10 . An autonomous working machine comprising or being communicatively connected to the computer system of claim 1 .
11 . The autonomous working machine of claim 10 , wherein the working machine comprises a tiltable body configured to carry a payload, the tiltable body being pivotable about a transverse axis located at the second end of the working machine.
12 . A computer-implemented method for controlling an electric propulsion system of an autonomous working machine comprising a first axle located near a first end of the working machine and a second axle located near a second end of the working machine, the electric propulsion system comprising: a first electric system configured to drive the first axle, the first electric system comprising a first electric energy storage system and a first electric motor, and a second electric system configured to drive the second axle, the second electric system comprising a second electric energy storage system and a second electric motor, the method comprising: by a processing circuitry of a computer system, determining a longitudinal gradient along an expected travelling path of the working machine, by the processing circuitry, determining charge levels of the first and second electric energy storage systems, respectively, and by the processing circuitry, controlling the working machine to assume a first orientation or a second orientation to travel along the expected travelling path, the first end of the working machine being a leading end in the first orientation, and the second end of the working machine being a leading end in the second orientation, wherein the orientation of the working machine is controlled in dependence on the determined longitudinal gradient and the determined charge levels.
13 . The method of claim 12 , comprising: by the processing circuitry, detecting an uphill road segment along the expected travelling path, in response to determining that the charge level of the first electric energy storage system exceeds the charge level of the second electric energy storage system by at least a first threshold amount, controlling, by the processing circuitry, the working machine to assume the second orientation prior to entering the detected uphill road segment, and in response to determining that the charge level of the second electric energy storage system exceeds the charge level of the first electric energy storage system by at least the first threshold amount, controlling, by the processing circuitry the working machine to assume the first orientation prior to entering the detected uphill road segment.
14 . A non-transitory computer-readable storage medium comprising program code for performing, when executed by the processing circuitry, the method of claim 12 .
15 . A non-transitory computer-readable storage medium comprising instructions, which when executed by the processing circuitry, cause the processing circuitry to perform the method of claim 12 .

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application claims priority to European Patent Application No. 23184182.6, filed on Jul. 7, 2023, the disclosure and content of which is incorporated by reference herein in its entirety. TECHNICAL FIELD The disclosure relates generally to control of electric propulsion systems in autonomous working machines. In particular aspects, the disclosure relates to a computer system and a method for controlling an electric propulsion system of an autonomous working machine. The disclosure can be applied to heavy-duty working machines and construction equipment, among other vehicle types. Although the disclosure may be described with respect to a particular working machine, the disclosure is not restricted to any particular working machine. BACKGROUND Heavy-duty electric working machines, such as electrically powered hauler vehicles and dump trucks, usually comprise more than one driven axle, such as two driven axles. Such working machines may either comprise a single electric system powering both axles, or separate electric systems, each powering one of the axles. A problem that may arise when separate electric systems are provided is that battery packs of the respective electric systems may discharge unevenly, i.e., battery packs used for powering a rear axle of the working machine may discharge more rapidly than battery packs used for powering a front axle. A charging stop may hence be necessary before the battery packs used for powering the front axle are fully discharged. SUMMARY According to a first aspect of the disclosure, a computer system comprising processing circuitry configured to control an electric propulsion system of an autonomous working machine comprising a first axle located near a first end of the working machine and a second axle located near a second end of the working machine is provided. The electric propulsion system comprises: a first electric system configured to drive the first axle, the first electric system comprising a first electric energy storage system and a first electric motor,a second electric system configured to drive the second axle, the second electric system comprising a second electric energy storage system and a second electric motor. The processing circuitry is configured to: determine a longitudinal gradient along an expected travelling path of the working machine,determine charge levels of the first and second electric energy storage systems, respectively,control the working machine to assume a first orientation or a second orientation to travel along the expected travelling path, the first end of the working machine being a leading end in the first orientation, and the second end of the working machine being a leading end in the second orientation, wherein the orientation of the working machine is controlled in dependence on the determined longitudinal gradient and the determined charge levels. The first aspect of the disclosure may seek to provide an in at least some aspect improved system for controlling an electric propulsion system comprising two separate electric systems configured to drive two separate axles. In particular, the first aspect may seek to provide such a system which may reduce problems with unbalanced charge levels between the respective energy storage systems of the two electric systems and which may hence increase the time between charging stops. By controlling the working machine to assume an orientation in dependence on the charge levels and the road gradient, the orientation may be selected to balance the charge levels between the energy storage systems. For an autonomous working machine, the orientation for travelling up or down a hill may hence be selected for charge balancing purposes. A technical benefit may include an improved total battery range of the working machine. In some embodiments, including in at least one example, the processing circuitry is further configured to: detect an uphill road segment along the expected travelling path,in response to determining that the charge level of the first electric energy storage system exceeds the charge level of the second electric energy storage system by at least a first threshold amount, control the working machine to assume the second orientation prior to entering the detected uphill road segment, andin response to determining that the charge level of the second electric energy storage system exceeds the charge level of the first electric energy storage system by at least the first threshold amount, control the working machine to assume the first orientation prior to entering the detected uphill road segment. Hence, an orientation of the working machine for travelling through the uphill road segment may be selected such that the energy storage system having the lowest charge level provides less electric power during the uphill travel than the energy storage system having the highest charge level. This may contribute to balancing of the charge le