METHOD OF CONTROLLING OPERATION OF AN ARTICULATED VEHICLE COMBINATION

Abstract

The present disclosure relates to a method of controlling operation of an articulated vehicle combination (AVC), the AVC comprising a tractor unit comprising a primary prime mover for propulsion of the AVC, a first trailer unit coupled to the tractor unit by a first articulated coupling, a dolly comprising a secondary prime mover, the dolly being coupled to the first trailer unit by a second articulated coupling, and a second trailer unit coupled to the dolly by a third articulated coupling, the method comprising determining at least one property indicative of a stability of the AVC; comparing the property with a predetermined property specific range; and controlling the secondary prime mover to generate a propulsion torque for the AVC when the property is within the predetermined property specific range.

Claims

1. A method of controlling operation of an articulated vehicle combination (AVC), the AVC comprising a tractor unit comprising a primary prime mover for propulsion of the AVC, a first trailer unit coupled to the tractor unit by a first articulated coupling, a dolly comprising a secondary prime mover, the dolly being coupled to the first trailer unit by a second articulated coupling, and a second trailer unit coupled to the dolly by a third articulated coupling, the method comprising: determining at least one property indicative of a stability of the AVC, the at at least one property comprising a coupling force parameter of at least one of the first, second, or third articulated couplings; comparing the coupling force parameter with a predetermined force parameter range; and controlling the secondary prime mover to generate a propulsion torque for the AVC when the coupling force parameter is within the predetermined force parameter range.

2. The method of claim 1, further comprising: reducing an operational capacity of the primary prime mover when controlling propulsion using the secondary prime mover.

3. (canceled)

4. The method a of claim 1, wherein the coupling force parameter comprises a lateral force component exposing the at least one of the first, second, or third articulated couplings to a lateral force during operation of the AVC.

5. The method of claim 1, wherein the coupling force parameter comprises a torque component exposing at least one of the first, second or third articulated couplings to a torque around a longitudinally extending geometric axis during operation of the AVC.

6. The method of claim 1, wherein the at least one property comprises an articulated angle of at least one of first, second or third articulated couplings during operation of the AVC, wherein the secondary prime mover is controlled to generate the propulsion torque when the articulated angle is within a predetermined angle range.

7. The method of claim 1, wherein the at least one property comprises a lateral slip parameter indicative of a lateral slip value of at least one wheel of the AVC, wherein the secondary prime mover is controlled to generate the propulsion torque when the lateral slip value is within a predetermined slip range.

8. The method of claim 1, further comprising: determining a first longitudinal force parameter value of the AVC during propulsion solely using the primary prime mover; and controlling the primary and secondary prime movers to contemporaneously generate a propulsion torque exposing the AVC to a second longitudinal force parameter value during a transition period when initiating propulsion using the secondary prime mover, the second longitudinal force parameter value being within a predetermined range from the first longitudinal force parameter value.

9. The method of claim 1, further comprising: determining a first lateral force parameter value of the AVC during propulsion solely using the primary prime mover; and controlling the primary and secondary prime movers to contemporaneously generate a propulsion torque exposing the AVC to a second lateral force parameter value during a transition period when initiating propulsion using the secondary prime mover, the second lateral force parameter value being within a predetermined range from the first lateral force parameter value.

10. The method of claim 1, further comprising: determining a first angle value of at least one of the first, second and third articulated couplings during propulsion solely using the primary prime mover; and controlling the primary and secondary prime movers to contemporaneously generate a propulsion torque exposing the AVC to a second angle value during a transition period when initiating propulsion using the secondary prime mover, the second angle value being within a predetermined range from the first angle value.

11. The method of claim 1, wherein the primary prime mover is an internal combustion engine of the tractor unit.

12. The method of claim 1, wherein the secondary prime mover is at least one electric machine of the dolly.

13. An articulated vehicle combination (AVC), control system configured to control operation of an AVC comprising a tractor unit comprising a primary prime mover for propulsion of the AVC, a first trailer unit coupled to the tractor unit by a first articulated coupling, a dolly comprising a secondary prime mover, the dolly being coupled to the first trailer unit by a second articulated coupling, a second trailer unit coupled to the dolly by a third articulated coupling, and at least one sensor arranged to sense at least one property indicative of a stability of the AVC, wherein the AVC control system comprises control circuitry configured to: receive a signal indicative of the property from the at least one sensor, the property comprising a coupling force parameter of at least one of the first, second, or third articulated couplings; compare the coupling force parameter with a predetermined force parameter range; and transmit a propulsion signal to the secondary prime mover, the propulsion signal allowing the secondary prime mover to generate a propulsion torque for the AVC when the coupling force parameter is within the predetermined force parameter range.

14. The AVC control system of claim 13, wherein the AVC control system comprises a tractor unit control system and a dolly control system, wherein the tractor unit control system is configured to control operation of the primary prime mover, and the dolly control system is configured to control operation of the secondary prime mover.

15. The AVC control system of claim 14, wherein the control circuitry is configured to transmit the propulsion signal to the dolly control system, the propulsion signal representing instructions which, when executed by the dolly control system, cause the secondary prime mover to generate the propulsion torque.

16. The AVC control system of claim 14, wherein the control circuitry is configured to transmit a propulsion reduction signal to the tractor unit control system, the propulsion reduction signal representing instructions which, when executed by the tractor unit control system, cause the primary prime mover to reduce its operational capacity.

17. An articulated vehicle combination (AVC) comprising a tractor unit comprising a primary prime mover for propulsion of the AVC, a first trailer unit coupled to the tractor unit by a first articulated coupling, a dolly comprising a secondary prime mover, the dolly being coupled to the first trailer unit by a second articulated coupling, a second trailer unit coupled to the dolly by a third articulated coupling, and the AVC control system of claim 13.

18. A computer program comprising program code means for performing the steps of claim 1 when the program is run on a computer.

19. A computer readable medium carrying a computer program comprising program means for performing the steps of claim 1 when the program means is run on a computer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The above, as well as additional objects, features and advantages, will be better understood through the following illustrative and non-limiting detailed description of exemplary embodiments, wherein:

[0043] FIG. 1 is a lateral side view illustrating an example embodiment of an articulated vehicle combination, where the articulated vehicle combination comprises a tractor unit, a first trailer unit, a dolly and a second trailer unit;

[0044] FIG. 2 is a top view of the tractor unit and the first trailer unit of FIG. 1;

[0045] FIG. 3 is a side view of the tractor unit and the first trailer unit of FIG. 1;

[0046] FIG. 4 is a rear view of the tractor unit in the articulated vehicle combination in FIG. 1;

[0047] FIG. 5 is a rear view of the first trailer unit in the articulated vehicle combination in FIG. 1;

[0048] FIG. 6 is a top view of the first trailer unit, the dolly and the second trailer unit of the articulated vehicle combination in FIG. 1;

[0049] FIG. 7 is a control system for controlling the articulated vehicle combination in FIG. 1 according to an example embodiment;

[0050] FIG. 8 is a further detailed illustration of the control system in FIG. 7; and

[0051] FIG. 9 is a flow chart of a method for controlling the articulated vehicle combination in FIG. 1 according to an example embodiment.

DETAILED DESCRIPTION

[0052] The present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. The disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness. Like reference character refer to like elements throughout the description.

[0053] With particular reference to FIG. 1, there is depicted an articulated vehicle combination (AVC) 100 in the form of a multi-trailer truck 100. The AVC 100 comprises a tractor unit 102, a first trailer unit 104, a dolly 106 and a second trailer unit 108. Although the AVC 100 depicted in FIG. 1 comprises four vehicle units, the present disclosure is equally applicable for a vehicle combination comprising arbitrary many vehicle units, such as e.g. also a fifth, a sixth, a seventh trailer unit, etc.

[0054] Moreover, the AVC comprises a primary prime mover 105 arranged on the tractor unit 102. The primary prime mover 105 is preferably an internal combustion engine, or an electric motor. Further, the dolly 106 comprises a secondary prime mover 107, such as preferably an electric motor or electric machine. Hereby, the AVC can be propelled by either the primary prime mover 105 or by the secondary prime mover 107, or by a combination of the primary prime mover 105 and the secondary prime mover 107.

[0055] Moreover, the tractor unit 102 is connected to the first trailer unit 104 by a first articulate coupling 110, the first trailer unit 104 is connected to the dolly 106 by a second articulate coupling 112, and the dolly 106 is connected to the second trailer unit 108 by a third articulate coupling 114. Hereby, the vehicle units are allowed to rotate relative to each other around a respective first 116, second 118 and third 120 substantially vertical geometric axis.

[0056] During operation, the articulated couplings 110, 112, 114 of the AVC 100 are exposed to coupling forces, such as e.g. longitudinal and lateral forces, as well as torque loads. Hence, the AVC 100 is exposed to a property indicative of the stability. This property will in the following also be referred to as a motion related parameters, such as the forces, articulated angles, torques, slip, etc. exposed to the AVC 100. Also, the articulated couplings 110, 112, 114 are exposed to torque loads around a longitudinally extending geometric axis of the AVC 100. These coupling forces are generated during operation of the AVC 100. In order to describe these coupling force parameters in further detail, reference is made to FIGS. 2-6 which illustrate an example embodiment of an AVC 100 comprising the tractor unit 102, the first trailer unit 104, the dolly 106 and the second trailer unit 108. Thus, the following disclosure will, for simplicity of understanding, not include all vehicle units in each of the following figures. However, it should be readily understood that the coupling force parameters of the non-illustrated articulated couplings are determined in a similar manner as for the articulated couplings described below.

[0057] Starting with FIG. 2, which is a top view of the tractor unit 102 and the first trailer unit 104. The AVC 100 is in FIG. 2 arranged in a somewhat exploded view so that the tractor unit 102 is separated from the first trailer unit 104. Thus, FIG. 2 is exploded in this manner to simplify the illustration of the coupling force parameters of the first articulated coupling 110 as well as the motion related parameters obtained from the first 102 and second 104 vehicle units.

[0058] As can be seen in FIG. 2, the tractor unit 102 turns to the left by an articulated angle ?. Thus, the tractor unit 102 and the first trailer unit 104 are rotated relative to each other around the articulated coupling 110 by the articulated angle ?. The articulated angle ? can be measured by e.g. an angle sensor, an input signal from the steering wheel, and/or from an Advanced driver-assistance system (ADAS). Further, during propulsion, the vehicle is exposed to a longitudinal acceleration component, a.sub.x1, and a lateral acceleration a.sub.y1. The lateral acceleration ay, is generated as the tractor unit 102 is turning. The longitudinal and lateral acceleration components can be determined by means of inertial measurement units (IMUs) or similar sensors.

[0059] The first trailer unit 104 is exposed to a longitudinal acceleration component, ?.sub.x2, as can also be obtained by an IMU. As the first trailer unit 104 in FIG. 2 is still operated straight forward, it is not exposed to a lateral acceleration component at this stage.

[0060] Furthermore, when the vehicle combination is operated, actuation forces, F.sub.x1, and F.sub.x2, of the tractor unit 102 and the first trailer unit 104 can be obtained from actuators of the vehicle, such as e.g. electric machines configured to generate an operating torque on the propelled wheels of the respective tractor unit 102 and the first trailer unit 104. Based on the above described motion related parameters, the following equations (1)-(6) can be generated to determine the coupling force parameters of the articulated coupling.

m.sub.1?.sub.x1=F.sub.x1+F.sub.xc1(1)

m.sub.2?.sub.x2=F.sub.x2+F.sub.xc2(2)

m.sub.1?.sub.y1=F.sub.y1?F.sub.y1?F.sub.yc1(3)

m.sub.2?.sub.y2=F.sub.y2?F.sub.yc2(4)

J.sub.z1{dot over (?)}.sub.z1=?F.sub.y1L.sub.x1+F.sub.yc1L.sub.c1(5)

J.sub.z2{dot over (?)}.sub.z2=F.sub.y2L.sub.x2?F.sub.yc2L.sub.c2(6)

Where:

[0061] m.sub.1 is the mass of the tractor unit 102; [0062] m.sub.2 is the mass of the first trailer unit 104; [0063] {dot over (?)}.sub.z1 is the angular acceleration of the tractor unit 102; [0064] {dot over (?)}.sub.z2 is the angular acceleration of the first trailer unit 104; [0065] F.sub.y1 is the lateral forces generated on the tractor unit 102; [0066] F.sub.y2 is the lateral forces generated on the first trailer unit 104; [0067] J.sub.z1 is the moment of inertia of the tractor unit 102; [0068] J.sub.z2 is the moment of inertia of the first trailer unit 104; [0069] L.sub.x1 is the longitudinal length from the center of mass of the tractor unit 102 to a position at which the lumped tractive force F.sub.x1 is exposed to the tractor unit 102; [0070] L.sub.c1 is the longitudinal length from the center of mass of the tractor unit 102 to the position of the articulated coupling 110; [0071] L.sub.x2 is the longitudinal length from the center of mass of the first trailer unit 104 to a position at which the lumped tractive force F.sub.x2 is exposed to the first trailer unit 104; [0072] L.sub.c2 is the longitudinal length from the center of mass of the first trailer unit 104 to the position of the articulated coupling 110; [0073] F.sub.xc1 is the longitudinal coupling force component as seen in a local coordinate system of the tractor unit 102; [0074] F.sub.yc1 is the lateral coupling force component as seen in a local coordinate system of the tractor unit 102; [0075] F.sub.xc2 is the longitudinal coupling force component as seen in a local coordinate system of the first trailer unit 104; and [0076] F.sub.yc2 is the lateral coupling force component as seen in a local coordinate system of the first trailer unit 104.

[0077] The angular accelerations {dot over (?)}.sub.z1 and {dot over (?)}.sub.z2 can, in a similar manner as the longitudinal and lateral acceleration components be determined by obtaining a signal from an IMU or similar sensor. The mass of the first 102 and second 104 vehicle units, as well as the moments of inertia J.sub.z1 and J.sub.z2 are also known beforehand.

[0078] Thus, the above equations (1)-(6) contains the known parameters m.sub.1, m.sub.2, ?.sub.x1, ?.sub.x2, ?.sub.y1, ?.sub.y2, {dot over (?)}.sub.z1, {dot over (?)}.sub.z2, J.sub.z1 and J.sub.z2 and the unknown parameters F.sub.xc1, F.sub.yc1, F.sub.xc2, F.sub.yc2, F.sub.y1, F.sub.y2 L.sub.x1 L.sub.x2. Thus, six equations and six unknown parameters, which presents an equation system which is solvable. In particular, the coupling force parameters F.sub.xc1, F.sub.yc1, F.sub.xc2 and F.sub.yz2 can be determined, which can be used for the application as described further below in relation to FIG. 8.

[0079] The above described longitudinal forces F.sub.x1 and F.sub.x2 are thus the sum of wheel torques, i.e. actuated torque from brake and/or propulsion units, among the wheels of the respective vehicle unit divided by the wheel radius.

[0080] Turning now to FIGS. 3-5, which are a side view and rear views of the AVC 100 according to an example embodiment. In particular, FIG. 4 is a rear view of the tractor unit 102 and FIG. 5 is a rear view of the first trailer unit 104. Motion related parameters already described in relation to FIG. 2 will not be described in further detail below but should be construed as also being present for the illustrations of FIGS. 3-5.

[0081] From the illustrations of FIGS. 3-5, the following equations (7)-(19) can be generated.

[00001]$\begin{array}{cc}{M}_{xc2}+F_{z212}?\frac{W_2}{2}-F_{z211}?\frac{W_2}{2}-m_2{a}_{y2}\left(h_2-h_t\right)=0& \left(7\right)\end{array}$$\begin{array}{cc}{M}_{xc1}+\left(F_{z111}+F_{z121}\right)?\frac{W_1}{2}-\left(F_{z112}+F_{z122}\right)?\frac{W_1}{2}-m_1{a}_{y1}\left(h_t-h_1\right)=0& \left(8\right)\end{array}$$\begin{array}{cc}{F}_{zc2}+F_{z21}-m_2{a}_{z2}=0& \left(9\right)\end{array}$$\begin{array}{cc}-F_{zc1}+F_{z11}+F_{z12}-m_1{a}_{z1}=0& \left(10\right)\end{array}$$\begin{array}{cc}{F}_{z11}=F_{z111}+F_{z112}& \left(11\right)\end{array}$$\begin{array}{cc}{F}_{z12}=F_{z121}+F_{z122}& \left(12\right)\end{array}$$\begin{array}{cc}{F}_{z21}=F_{z211}+F_{z212}& \left(13\right)\end{array}$$\begin{array}{cc}{F}_{xc2}\cos \left(?\right)+F_{\mathrm{yc}2}\sin \left(?\right)+m_2{a}_{x2}-F_{x2}=0& \left(14\right)\end{array}$$\begin{array}{cc}{F}_{xc1}+F_{x1}-m_1{a}_{x1}=0& \left(15\right)\end{array}$$\begin{array}{cc}{F}_{\mathrm{yc}1}=F_{y11}+F_{y12}-m_1{a}_{y1}& \left(16\right)\end{array}$$\begin{array}{cc}{F}_{\mathrm{yc}2}\cos \left(?\right)-F_{xc2}\sin \left(?\right)-m_2{a}_{y2}+F_{y21}=0& \left(17\right)\end{array}$$\begin{array}{cc}{F}_{x1}?h_t-m_1{a}_{x1}?\left(h_t-h_1\right)=0& \left(18\right)\end{array}$$\begin{array}{cc}{m}_2{a}_{x2}?\left(h_2-h_t\right)-F_{x2}?h_t=0& \left(19\right)\end{array}$

where: [0082] M.sub.xc1 is the coupling torque component as seen in a local coordinate system of the tractor unit 102; [0083] M.sub.xc2 is the coupling torque component as seen in a local coordinate system of the first trailer unit 104; [0084] h.sub.1 is the height from ground to the center of mass of the tractor unit; and [0085] h.sub.2 is the height from ground to the center of mass of the first trailer unit

[0086] As described above in relation to the description of FIG. 2, the acceleration parameters can be determined by e.g. IMUs and the tractive forces can be obtained from the actuators. Hereby, the vertical coupling force F.sub.yc and the coupling torque M.sub.xc of the articulated coupling can be determined.

[0087] Turning to FIG. 6, which illustrates the first trailer unit 104, the dolly 106 and the second trailer unit 108. The first trailer unit 104 and the dolly 106 are rotated relative to each other by an articulated angle ?.sub.1 at the second articulated coupling 112, while the dolly 106 and the second trailer unit 108 are rotated relative to each other by an articulated angle ?.sub.2 at the third articulated coupling 114.

[0088] As can be seen by the illustration in FIG. 6, the second articulated coupling 112 is exposed to a lateral force component F.sub.yct and a longitudinal force component F.sub.xct as seen in a local coordinate system of the second trailer unit 104. Furthermore, the third articulated coupling 114 is exposed to lateral force component F.sub.y,cd1 and a longitudinal force component F.sub.x,cd1 as seen in a local coordinate system of the dolly 106, as well as exposed to lateral force component F.sub.y,cd2 and a longitudinal force component F.sub.x,cd2 as seen in a local coordinate system of the second trailer. The dolly is also exposed to a longitudinal force component F.sub.xd and a lateral force component F.sub.yd as seen in the local coordinate system of the dolly 106. By means of the force components depicted in FIG. 6, the following equations (20)-(21) can be generated for the third articulated coupling 114:

F.sub.x,cd1 cos(?.sub.1)+F.sub.x,cd2?F.sub.y,cd1 sin(?.sub.1)=0(20)

F.sub.y,cd2+F.sub.y,cd1 cos(?.sub.1)+F.sub.x,cd1 sin(?.sub.1)=0(21)

When the articulated angle ?.sub.1 equals 90 degrees, F.sub.x,cd2=F.sub.y,cd1 and F.sub.y,cd2=?F.sub.x,cd1.
When the articulated angle ?.sub.1 equals 0 degrees, F.sub.x,cd1=F.sub.x,cd2 and F.sub.y,cd2=?F.sub.y,cd1.

[0089] Turning to FIG. 7 which illustrates an AVC control system 600 according to the present disclosure. The AVC control system 600 depicted in FIG. 7 is arranged to determine the above described longitudinal coupling force F.sub.xc and lateral coupling force F.sub.yz. It should however be readily understood that the AVC control system 600 is equally applicable for determining the vertical coupling force F.sub.xc and the coupling torque M.sub.xc by implementing also the equations (7)-(21) described above, i.e. for all vehicle units forming part of the AVC.

[0090] The AVC control system 600 comprises control circuitry 650 which may each include a microprocessor, microcontroller, programmable digital signal processor or another programmable device. The AVC control circuitry 650 may also, or instead, each include an application specific integrated circuit, a programmable gate array or programmable array logic, a programmable logic device, or a digital signal processor. Where the control circuitry 650 includes a programmable device such as the microprocessor, microcontroller or programmable digital signal processor mentioned above, the processor may further include computer executable code that controls operation of the programmable device. It should be understood that all or some parts of the functionality provided by means of the control circuitry 650 may be at least partly integrated with the below described IMUs 130, 230, actuators 140, 240, angle sensor 250 and mass and inertia estimator 602.

[0091] As can be seen, the AVC control system 600 receives a longitudinal acceleration component ?.sub.x1, a lateral acceleration component ?.sub.y1 and a rotational velocity component ?.sub.z1 from an IMU 130 of the tractor unit 102. The AVC control system 600 also receives longitudinal wheel forces F.sub.x, from the tractor unit 102, which are defined as a sum, calculated by a first force summation module 170, of longitudinal wheel forces received from actuators 140 of the tractor unit 102.

[0092] Moreover, the control system receives a longitudinal acceleration component ?.sub.x2, a lateral acceleration component ?.sub.y2 and a rotational velocity component ?.sub.z2 from an IMU 230 of the first trailer unit 104. The AVC control system 600 also receives longitudinal wheel forces F.sub.x2 from the first trailer unit 104, which are defined as a sum, calculated by a second force summation module 270, of longitudinal wheel forces received from actuators 240 of the first trailer unit 104. Also, the control system receives an articulated angle ? of the articulated coupling 110, i.e. the relative angular displacement between the first 102 and second 104 vehicle units. Although FIG. 7 illustrates that the articulated angle is received from an angle sensor 250 of the first trailer unit 104, this angle sensor 250 can equally form part of the tractor unit 102.

[0093] Moreover, the AVC control system 600 receives parameter values indicative of vehicle mass m and moment of inertia J from a mass and inertia estimator 602. Thus, the mass and inertia estimator 602 is arranged to transmit parameter values indicative of the mass m.sub.1 of the tractor unit 102, the mass m.sub.2 of the first trailer unit 104, the moment of inertia J.sub.1 of the tractor unit 102 and the moment of inertia J.sub.2 of the first trailer unit 104.

[0094] When receiving the motion related parameters of the first 102 and second 104 vehicle units, the control system determines, based on the above described equations, the coupling force parameters, here indicated as the longitudinal F.sub.xc and lateral F.sub.yz coupling force parameters, of the articulated coupling. Although not depicted in FIG. 7, the control circuit 650 can also transmit torque components and articulated angles of the various articulated couplings of the AVC 100 as will be evident with the below disclosure of FIG. 8, which is a further detailed illustrations of the AVC control system. The AVC control system 600 comprises a dolly control system 806 arranged to control operation of the secondary prime mover 107.

[0095] Articulated forces and torques as described above are transmitted to a comparison module 802. Hereby, the forces and torques are compared to a threshold value, i.e. a predetermined property range. If the forces and torques fulfil the requirements, i.e. are within the predetermined property range, a signal is transmitted to the dolly control system 806 indicating digit {1}, i.e. the requirements are fulfilled. If not fulfilled, i.e. outside the predetermined property range, the signal is indicating digit {0}. Also, current articulated angles of the different articulated couplings are transmitted to the comparison module 802. If the articulated angle(s) are within a predetermined angle range, the comparison module 802 transmit a signal indicating digit {1}, i.e. the angle requirements are fulfilled. If the angle requirements are not fulfilled, i.e. outside the predetermined property range, the signal is indicating digit {0}.

[0096] The dolly control system 806 receives the signals from the comparison module 802. If the combination of the signals indicate digit {1}, i.e. the forces, torques and articulated angles are within their predetermined property range, the dolly control system 806 transmits a control signal to the secondary prime mover 107 to generate a propulsion torque for the AVC. At the same time, the dolly control system 806 can control the primary prime mover to reduce its operational capacity, preferably controlling the primary prime mover to be shut off.

[0097] On the other hand, if the combination of the signals indicate digit {0}, i.e. at least one of the forces, torques and articulated angles are not within their predetermined property range, the dolly control system 806 awaits the control of the secondary prime mover.

[0098] In addition to the signals received from the comparison module 802, the dolly control system 806 can also receive a signal from a lateral slip module 804. In particular, the lateral slip module 804 receives lateral slip parameter indicative of a lateral slip value of at least one wheel of the AVC 100. The lateral slip module 804 compares the lateral slip parameter with a predetermined slip range. If the lateral slip parameter is within the predetermined slip range, the lateral slip module 804 transmits a digit {1} to the dolly control system 806. If the lateral slip parameter is not within the predetermined slip range, the lateral slip module 804 transmits a digit {0} to the dolly control system 806. The dolly control system 806 controls the secondary prime mover to generate a propulsion torque if also the lateral slip fulfils the predetermined requirements.

[0099] In order to operate the AVC 100 in a convenient manner and not exposing e.g. an operator to an uncomfortable operation when transitioning form the propulsion using the primary prime mover to propulsion using the secondary prime mover, the AVC control system 600 also determines a first longitudinal force parameter value of the AVC during propulsion solely using the primary prime mover. The control circuit transmits a control signal to the dolly control system 806 to control the primary and secondary prime movers to contemporaneously generate a propulsion torque exposing the AVC to a second longitudinal force parameter value during a transition period when initiating propulsion using the secondary prime mover, the second longitudinal force parameter value being within a predetermined range from the first longitudinal force parameter value. Preferably, the first and second longitudinal force parameter value are substantially the same for optimized comfort.

[0100] In a similar manner, the control circuit may transmit control signal to the dolly control system 806 to control the primary and secondary prime movers to contemporaneously generate a propulsion torque exposing the AVC to substantially the same lateral forces and angles of the articulated coupling during the transition period when initiating propulsion using the secondary prime mover.

[0101] Although the description in relation to FIGS. 7 and 8 are directed to solely one AVC control system, the AVC control system may comprise comprises a tractor unit control system in addition to the above described dolly control system, wherein the tractor unit control system is configured to control operation of the primary prime mover, and the dolly control system is configured to control operation of the secondary prime mover.

[0102] In order to sum up, reference is made to FIG. 9 which is a flow chart of a method for controlling operation of the AVC 100 depicted in FIG. 1. During operation, at least one property indicative of the stability of the AVC is determined S1. As described above, the property indicative of the stability of the AVC may relate to e.g. coupling force parameters of the articulated couplings, articulated angles, torque components, etc. exposed to the AVC 100 during operation. The property is compared S2 to a predetermined property range, i.e. a property in the form of a lateral force is compared to a force threshold, while a property in the form of an articulated angle is compared to an angle threshold. When the property is within the predetermined property specific range, the secondary prime mover is controlled S3 to generate a propulsion torque. Hence, when the property is within the predetermined property specific range it is considered safe to initiate propulsion of the AVC 100 using the secondary prime mover 107.

[0103] It is to be understood that the present disclosure is not limited to the embodiments described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims.