Steering control method and system for reversing a vehicular assembly with more than one articulation

Abstract

The invention relates to a steering control method and system for reversing a vehicular assembly with more than one articulation. The system comprises sensing means to obtain angles α and β, defined between a first element (1) and an intermediate element (2) and between the intermediate element and a rear element (3), respectively; actuator means (7) to change a rotation angle δ of steering means (8) of the intermediate element; and an electronic control module (6), configured to determine a pair of unique reference angles αr and βr for each value of the sum α+β. The method comprises calculating the value of the angle δ that keeps angles α and β at reference values αr and βr; and sending the δ angle value to the actuator means to change the position of the steering means, such that the intermediate element is forcibly repositioned to the reference values.

Description

[0001] METHOD AND DIRECTIONAL CONTROL SYSTEM FOR PERFORMING REVERSE MANEUVERS OF A VEHICLE ASSEMBLY WITH MORE THAN ONE JOINT

[0002] DESCRIPTION

[0003] OBJECT OF THE INVENTION

[0004] The object of the invention is a method by which the required space is reduced and the performance of reverse maneuvers is facilitated with vehicle assemblies that have more than one joint.

[0005] The invention also relates to an autonomous and interchangeable system that technically responds to the proposed method.

[0006] BACKGROUND OF THE INVENTION

[0007] In the current state of the art, the most common use of single-articulated vehicle combinations in heavy goods transport is the use of single-articulated vehicle combinations.

[0008] The most common vehicle combination in the global heavy goods transport market consists of a tractor unit pulling a trailer connected in an articulated manner by a "Kingpin."

[0009] These single-articulated vehicles perform maneuvers in relatively confined spaces, and this maneuvering technique is mastered by most heavy-duty transport drivers.

[0010] There are other configurations that are also common in the transport sector, such as those formed by a truck and trailer combination, which may have a single joint if the trailer has central axles, or two joints if the trailer has separate axles.

[0011] With a center-axle trailer, maneuvering is easier and takes less space than with a split-axle trailer.

[0012] With split-axle trailers, having two articulations, reversing maneuvers are much more complicated, since the trailer is very sensitive to the driver's steering input and the vehicle usually has to be completely straightened to be able to reverse, so a lot of space is needed for reversing maneuvers into the discharge chute.

[0013] There are also even longer and more complex configurations that may have three or more joints and more than one trailer in the vehicle combination. The more joints a vehicle combination has, the more difficult it will be to handle in reverse maneuvers.

[0014] There are some references in the technical literature to control systems for maneuvering high-capacity vehicles or vehicle combinations with more than one articulation. One such study is a study by the Eindhoven University of Technology called "Analysis of high-capacity vehicles for Europe," which can be found at the following link: https: / / pure.tue.nl / ws / portalfiles / portal / 135389218 / 20191003_Kural.pdf. This study analyzes the equations of motion for vehicles with multiple articulations and conducts maneuverability control tests in reverse accesses where mirrors and ultraviolet lights are used to control the rear trailer. However, the study does not establish a maneuverability method, but simply an analysis of the maneuvers to be performed.

[0015] Another study is the one conducted by the University of Malaga, Spain, “Steering the Last Trailer as a Virtual Tractor for Reversing Vehicles With Passive On- and Off-Axle Hitches”, which can be accessed through the link: https: / / ieeexplore.ieee.org / document / 6413219. This paper discloses a practical strategy for the reverse motion of a vehicle pushing two passive trailers with any combination of hitches, either on- or off-axle. The last trailer is defined as a virtual tractor that can be steered along paths of different curvatures, as a single non-holonomic vehicle. Kinematic relationships are then proposed to translate the resulting motion commands to the actual tractor. The paper extends previous work by specifically addressing the propagation of virtual setpoints across on-axle hitches.This case is difficult because direct propagation cannot be achieved due to the kinematic constraints imposed by current joint angles. The method has been experimentally applied to both autonomous path following and in-line operator steering using a tracked mobile robot with two different on- and off-axis trailer combinations. The results indicate applicability in autonomous vehicles and advanced driver assistance systems.

[0016] This study and other similar ones use different technical strategies to achieve the same objective, such as being able to guide the entire tractor and trailer assembly along a given path, taking the entire assembly in an aligned manner or with gentle curves along a path, since what is sought is that some elements push the others looking for the most suitable balance points to perform this push so the relative angles between some and other elements of the vehicle assembly will be small, they are not capable in any case of performing maneuvers with tight curves which implies adopting larger angles between the different elements (since these large angles would destabilize the assembly that could not follow the path) in order to reduce the space needed when entering a discharge mouth or performing a turning maneuver in a reduced space.

[0017] These studies attempt to replace the driver during the maneuver, using a device on the steering wheel to perform the movements necessary to maintain balance. This is because it is impossible for a person to perform the high-frequency balancing movements these devices perform.

[0018] These studies also introduce electronic and / or mechanical components in both the towing vehicle and each of the trailers, so they are not ultimately applicable in practice since legislation currently prevents communication regarding steering between the different elements that make up the vehicle assembly, nor between them and the tractor head, due to the lack of a standardized communication protocol worldwide, in addition to being too expensive, having too many components and complexity considering the current margins and the technological level currently available in the transport sector.

[0019] The use of vehicle combinations with two or three joints is less common in the state of the art than those with a single joint. Furthermore, they are used primarily, and almost exclusively, for very long journeys on round-trip circuits or for specific uses. There are two important constraints that significantly limit the potential use of these longer vehicle combinations with two or more joints: legislative limitations and the limited maneuvering capacity, primarily in reverse, that these vehicles currently have.

[0020] Therefore, the state of the art lacks solutions that can help improve the maneuverability of these vehicle assemblies and reduce the space required for such maneuvers, while also complying with the strict legal restrictions currently in place worldwide regarding steering, while remaining simple and, above all, inexpensive.

[0021] DESCRIPTION OF THE INVENTION

[0022] The present invention discloses a method, and a system that responds to that method, which allows simplifying the problem of reversing maneuver of a vehicle assembly consisting of more than one joint, being simple and very cheap, since it continues with the human element as controller and director of the maneuver, but managing a much simpler vehicle assembly, which will have functionally the equivalent complexity to one with a single joint.

[0023] Starting with the simplest case, which is a vehicle assembly with two joints, there is a front element or tractor head and an intermediate element joined by a first joint, and a second joint that joins the intermediate element with the rear element, the method consists of relocating the intermediate element continuously in an objective angular position that will be determined based on the angle formed between the first and second element, the angle formed between the second and third element and the dimensions of the elements that make up the vehicle assembly, in this way during the reverse maneuver a vehicle assembly with 2 joints will operate as if it had only 1 joint, since the intermediate element will operate as if it were the virtual joint or ball joint itself that will be located at all times in an objective position forced by the directional means at its disposal,giving the assembly a maneuvering capacity similar to, and in many cases superior to, a vehicle with a single joint.

[0024] In order to solve the aforementioned problems, a first aspect of the present invention relates to a directional control system for performing maneuvers of a vehicle assembly with more than one joint by a user, where the vehicle assembly comprises the first element or tractor head comprising a first joint, an intermediate element, connected to the tractor head by means of the first joint, which comprises a second joint and a rear element, connected to the intermediate element by means of the second joint. The system comprises:

[0025] - directional means located in the intermediate element,

[0026] - a first sensor, configured to detect a first relative position of the longitudinal axis of the tractor head with respect to the longitudinal axis of the intermediate element, where the first relative position defines an angle a.

[0027] - a second sensor, configured to detect a second relative position of the longitudinal axis of the intermediate element with respect to the longitudinal axis of the rear element, where the second relative position defines an angle p.

[0028] - a third sensor configured to detect a direction of movement S of the vehicle assembly in reverse, at which time the directional system can be activated;

[0029] - actuating means of the directional means, configured to modify a position of the directional means, where modifying the position of the directional means results in a modification of an angle 5 defined between the directional means of the intermediate element with respect to the longitudinal axis of the intermediate element;

[0030] - an electronic control module, fed back with the angles a and p, where in the event of detecting a reverse direction of travel S, it is configured to determine a pair of reference angles ar and pr unique for each value of the sum a+p, calculate a value for angle 5 that maintains the angles a and p at the reference values ​​ar and pr; and send a signal to the actuating means (7) of the directional means (8) to modify the position of the directional means, placing them at the calculated value of angle 5, such that, as a result of forcibly maintaining, by the directional means, the relative position of the intermediate element (2) at the reference angles ar and pr; the operation of a vehicular assembly with a single joint is simulated.

[0031] For each value of the angle a+p (angle between the first element and the rear element), there is a single reference value for the angles a and P; therefore, the intermediate element for each value of a+p will have a single reference position that is reached by means of the action of the directional means, this is the reason why the operation of this vehicular assembly is appreciated by the driver as if he were driving an assembly with a single joint, since the intermediate element is acting as a virtual ball joint or joint that is automatically placed in the most appropriate position between the tractor head (1) and the rear element (3), without the driver having to worry about this part of the vehicle, he will only monitor the tractor head and the rear element, as is done in assemblies with a single joint.

[0032] Thus, advantageously, the objective of simplifying the problem of the two-articulated vehicle combination is achieved, leaving the driver with the complexity of handling equivalent to handling a vehicle combination with a single joint, since the driving of these vehicle combinations with a single joint is well known today by the vast majority of drivers, using certain maneuvers, it is possible to maneuver with them in reverse to enter narrow areas and loading / unloading mouths in relatively small spaces and with maneuvers with very tight radii of curvature.

[0033] Additionally, one of the embodiments of the invention contemplates knowing the basic length dimensions of the different elements of the vehicle assembly, that is, the distances between axles and the distances between the axles and the joints, in order to be able to draw their radii of curvature and thus be able to perform the calculations by the electronic control module in a more precise and optimized manner.

[0034] Additionally, one of the embodiments of the invention has a fourth sensor configured to detect the angle 5 defined between the directional means of the intermediate element with respect to the longitudinal axis of the intermediate element; and where the electronic control module is also fed back with the angle 5 and has an interface for driver information, in this way the electronic control module based on the values ​​provided by a, p and 5 generates alert signals in said interface so that it can rectify the turn of the steering wheel of the tractor head and / or the direction of advance at the moment in which the angle 5 of the directional means is close to its pre-established turning limits, which advantageously helps the driver to ensure that the vehicle assembly remains operating within pre-established angular values.

[0035] Specifically, in one embodiment of the invention, an interface between the electronic control module and the user is contemplated, with at least one on / off indicator, a forward / reverse indicator and an over-speed indicator, configured to establish actuator speed limits (omax and omin) in the electronic control module; where the electronic control module is also configured to compare the received values ​​of angle 5 with the established omax and omin limit values ​​and, based on the comparison, send an activation signal to the over-speed indicator.

[0036] Additionally, one embodiment of the invention has a fifth sensor V configured to detect the direction and speed of rotation of the wheels of the intermediate element; where the electronic control module is also provided with feedback with the angle 5, detected by the fourth sensor, and the direction and speed of rotation, detected by the fifth sensor, and where the electronic control module is also configured to estimate a turning angle of some steering means of the tractor head, defined as angle 0est, based on geometric relationships between angle a, angle 5 and direction and speed of rotation of the wheels of the intermediate element. This "estimated value of rotation of 0est", together with the values ​​of a and p, when operating in reverse, can be used both to optimize the calculation / obtaining of the values ​​ar, r and to optimize the algorithm for calculating angle 5.

[0037] Additionally, in countries where legislation allows it, the invention contemplates that the electronic control module, in addition to being fed back with the angles a, p, having the reverse signal S and the significant dimensions of the length of the vehicle assembly, also has the angle 0 provided by the tractor head. This will be used in an even more precise way both to optimize the calculation / obtaining of the values ​​ar, pr and to optimize the angle calculation algorithm 5.

[0038] In one of the preferred embodiments of the invention, the first, second, third, and fourth sensors, the reverse gear sensors or signals, the fourth sensor, and the fifth sensor, the actuating means, the directional means, and the electronic control module are arranged in the intermediate element, where the intermediate element is independent of the rest of the vehicle assembly components. Thus, advantageously, the present invention is easily applicable to different vehicle assemblies, since it becomes fully operational simply by exchanging the intermediate element.

[0039] In one of the preferred embodiments of the invention, the directional means are constituted by directional axles, their pivot point being at the junction between the axle and the rim of the wheel, where the angle 5 is measured by the sensor. The actuating means of the directional axles may comprise:

[0040] - hydraulic cylinders, widely known in the industry;

[0041] - independent motorized wheels in the intermediate element, which by rotating at different speeds perform their function as actuators.

[0042] In this case, the actuators of the steering means comprise a sensor configured to detect their independent rotational speeds; and the electronic module is configured to estimate a difference in rotational speed between the motorized wheels that causes the position of the steering means to change until the calculated value of angle 5 is reached; and send the corresponding signal to the actuator means.

[0043] Using independent motorized wheels as an actuator on a steering axle is a particularly advantageous solution in that it provides a dual function at minimal cost:

[0044] - on the one hand, the backward maneuver can be controlled according to the present invention; and

[0045] - On the other hand, once uncoupled from the tractor head, the intermediate and rear elements are motorized, equipped with a small engine with high torque and low power, to move at low speed and reposition themselves within a warehouse or work area.

[0046] In another of the preferred embodiments of the invention, the directional means are constituted by a slewing ring that allows the complete axis / s of the intermediate element to rotate with respect to the intermediate element, the sensor to measure the angle 5 is located in the slewing ring located between both, the actuating means of the directional axes are constituted by hydraulic cylinders.

[0047] In another preferred embodiment of the invention, the directional means comprise a pivoting lance, where the intermediate element is configured to pivot relative to the pivoting lance at a point; where the actuators of the directional means comprise motor means configured to motorize each wheel independently and a sensor configured to detect their independent rotation speeds; and where the system also comprises: two rotation sensors at the junction between the lance and the tractor head (4) and the pivot between the lance and intermediate element (102) respectively; and where the electronic module is also configured to estimate a difference in rotation speed between the motorized wheels that causes the modification of the position of the directional means, until reaching the calculated value of angle 5; and send the corresponding signal to the actuator means.

[0048] A second aspect of the present invention relates to a directional control method for performing maneuvers of a vehicle assembly with more than one joint by a user, where the vehicle assembly comprises a first element or tractor head comprising a first joint, an intermediate element, connected to the tractor head by means of the first joint, which comprises a second joint, and a rear element, connected to the intermediate element by means of the second joint. The system comprises the following steps:

[0049] - detecting, by a first sensor, a first relative position of the longitudinal axis of the tractor head with the longitudinal axis of the intermediate element, where the first relative position defines an angle a;

[0050] - detecting, by a second sensor, a second relative position of the longitudinal axis of the intermediate element with the longitudinal axis of the rear element, where the second relative position defines an angle P;

[0051] - detect, by a third sensor in the intermediate element or reverse signal from the tractor head, configured to know when the direction of travel S is in reverse, at which time the directional system can be activated;

[0052] - determine a pair of reference angles ar and r unique for each value of the sum a+P;

[0053] - calculate a value for an angle 5, defined by the directional means of the intermediate element with respect to the longitudinal axis of the intermediate element, which maintains the angles a and p at the reference values ​​ar and pr;

[0054] - send, through the electronic control module (6), a signal to the actuating means (7) of the directional means (8) to modify the position of the directional means to the value calculated for angle 5, such that, as a result of the directional means forcibly maintaining the relative position of the intermediate element (2) at the reference angles ar and pr, the operation of a vehicle assembly with a single joint is simulated. Thus, advantageously, the directional wheels of the intermediate element act in an "active" manner, forcing the sought-after positions to achieve the aforementioned balance of forces, by placing the directional means in a position that produces a deformation in the wheels similar to that acquired when cornering, in order to, in this way, compensate for all the forces exerted on them by the rest of the elements of the vehicle assembly and placing themselves in the appropriate position for the vehicle assembly to follow the sought-after trajectory.

[0055] By turning the steering wheel left or right, the driver will modify the value of the angles a and P, causing the directional wheels of the intermediate element to relocate the intermediate element to the optimal position to achieve the desired effect of providing vehicle behavior for the driver equivalent to driving a set with a single joint.

[0056] Additionally, in one of the embodiments of the invention, it is contemplated to have the basic dimensions of the length of the vehicle assembly, that is, distances between axles and distances between axles and joints, receive these dimensions by the control module and use them to optimize all the calculations and estimates made by the electronic control module.

[0057] Additionally, in one of the embodiments of the invention it is contemplated,

[0058] - detecting, by a fourth sensor, the angle 5 defined between the directional means of the intermediate element with respect to the longitudinal axis of the intermediate element;

[0059] - supply, from a user interface, the electronic control module with the rotation limits of the actuators (7) (omax and Omin);

[0060] - compare, in the electronic control module, the detected value of 5 with the limit values ​​ómax and órnin,

[0061] - send, from the electronic control module, based on the comparison, an activation signal to an overshoot indicator (9.3) of the interface.

[0062] Additionally, in one of the embodiments of the invention it is additionally contemplated,

[0063] - detect, by a fifth sensor V, the direction of travel and the speed of rotation of the wheels of the intermediate element;

[0064] - estimate, by the electronic control module, a turning angle of the steering means of the tractor unit, defined as angle Qest, based on geometric relationships between angle a, angle 5 and the direction and speed of rotation of the wheels of the intermediate element; and

[0065] - modify the reference angles ar and pr and the calculated value of 5 according to the value of the angle Qest.

[0066] Additionally, one of the embodiments of the invention contemplates:

[0067] - receive, via the feedback electronic control module, a steering angle of 0 of the tractor unit's wheels; and

[0068] - modify the reference angles ar and pr and the calculated value of 5 according to the detected value of angle 0.

[0069] There are at least 4 operational improvements to this procedure and system proposed with respect to the current state of the art, which are as follows:

[0070] 1- The driver will perceive the vehicle assembly as having a first element or tractor head, a rear element or trailer, and an intermediate element functioning as a ball joint or articulation, making references and driving much easier with this configuration.

[0071] It can be maneuvered in the same way as single-joint vehicles, positioning the rear element or trailer, even partially skidding it to position it as necessary, close to the perpendicular to the discharge opening, with maneuvers similar to those performed today with single-joint vehicles.

[0072] 2- The three elements of the vehicle assembly function as a whole, and can move and rectify on both sides, having a maneuverability even greater than vehicles with a single joint, due to the advantageous location of the steering means in the front part of the rear element.

[0073] To date, all known main or auxiliary steering systems for this type of vehicle assemblies do not have this ability to maneuver on both sides of the rear element, they are only capable of maneuvering to the same side to correct their trajectory slightly and using a lot of space since each time the angle of the steering axis of the tractor varies, the relative positions between the tractor, intermediate element and rear element must vary, so they need a certain distance to reposition themselves and to be able to maintain relative angles that are not very accentuated between them, looking for balance points where each element pushes the next (as the known solutions in the current state of the art have been oriented), so that in the final part of the maneuver they have to straighten the entire vehicle assembly for its entry into the discharge mouth.Furthermore, they usually have to rectify several times before the final entry, because they don't have the option of rectifying on both sides. This ultimately leads to the rest of the systems requiring much more free space in front of the discharge opening and performing many more maneuvers.

[0074] 3- The angles a and p are positioned in the direction of the main rotation to be performed, so the intermediate element itself performs a large part of the rotation, leaving the directional elements with the main function of continuously rectifying the position of the intermediate element to force the balance of forces at the designated points. The position adopted by the assembly is also the most suitable for entering the discharge mouth, performing a minimum sweep.

[0075] Finally, with all these features mentioned above in points 1 to 3, the improvement in maneuvering translates into a reduction in the number of maneuvers, their complexity, and the space required for the maneuver.

[0076] 4- The entire proposed directional control system is housed in the intermediate element (2), making it completely interchangeable and flexible from a logistical point of view. This aspect is not known in the state of the art, where electronic, mechanical or similar elements are always required from other elements or to be located in other elements of the vehicle assembly, mainly related to the tractor, which greatly limits flexibility from a logistical point of view and, in many cases, the possibility of effective implementation from a legislative point of view, which in most countries does not allow communication, in terms of steering, between tractor and trailers.

[0077] The present invention presents a method, and a system that carries out said method, to carry out reverse maneuvers in a vehicle assembly with more than one joint. It is achieved that at low speed and in reverse, once the system is activated, it operates in a totally automatic manner, converting a vehicle assembly with two joints into an assembly that operates as if it had only one, for all maneuvers that can be carried out in reverse, straight ahead, entering the loading / unloading mouth, turning right and left, etc.

[0078] The maneuvers for entering the dump can be performed in a single operation, as the vehicle is controlled, allowing controlled turns to the right and left at all times.

[0079] The method presented is primarily applicable to two- and three-articulated vehicle combinations, allowing for the widespread use of these longer vehicles by radically improving their maneuverability, resulting in cost savings, a reduction in the surface area of ​​logistics parks and parking areas where these trucks maneuver, and, of course, contributing to the reduction of CO2 emissions.

[0080] This solution is also applicable not only to trucks, but also to agricultural vehicles, construction vehicles, urban buses, light-duty vehicle transport, caravans, and, in general, all transportation or mobility sectors that use or are likely to use multiple joints in their vehicle assemblies.

[0081] DESCRIPTION OF THE DRAWINGS

[0082] These and other features and advantages of the invention will become more clearly apparent from the following detailed description of a preferred embodiment, given solely as an illustrative and non-limiting example, with reference to the accompanying figures.

[0083] Figure 1a represents a side view of a vehicle assembly with two joints.

[0084] Figure 1 b represents a plan view of the vehicle assembly in Figure 1a in a circular layout.

[0085] Figure 2 represents a plan view of the vehicle assembly in Figure 1a in a circular layout with the intermediate element rectifying to the left.

[0086] Figure 3 represents a plan view of the vehicle assembly in Figure 1a in a circular layout with the intermediate element rectifying to the right.

[0087] Figure 4 represents the block diagram of the system operation in a first embodiment.

[0088] Figure 5 represents the block diagram of the system operation in a second embodiment.

[0089] Figure 6 represents the block diagram of the operation of the system in a third embodiment.

[0090] Figure 7 represents a plan view of the tractor head and the intermediate element and the geometric elements used for the calculation of 0est.

[0091] Figure 8 represents an embodiment of the interface that the driver sees in the cab.

[0092] Figures 9a - 9e represent a plan view of the vehicle assembly, with details of the operation of the intermediate element as a virtual ball joint or articulation.

[0093] Figures 10a - 10e represent a plan view of the vehicle assembly in different maneuvering positions.

[0094] Figure 11a represents a plan view and a side view of a dual-axis steering dolly.

[0095] Figure 11b represents a semi-trailer coupled to a dolly.

[0096] Figure 11c represents a trailer link.

[0097] Figure 11 d represents a plan view and a side view of a simple steering axle.

[0098] Figure 11e represents a trailer coupled to the axle of Figure 11d.

[0099] Figure 11f represents a center-axle trailer.

[0100] Figure 12a shows a plan view of an intermediate element coupled to a tractor head with a standard drawbar and motorized wheels.

[0101] Figure 12b shows a plan view of an intermediate element coupled to a tractor head with a pivoting drawbar and motorized wheels.

[0102] Figure 13a represents a side view of a vehicle assembly with two joints, with an intermediate element being a link-trailer like the one in Figure 11c.

[0103] Figure 13b represents the deformation that occurs in the wheel during the maneuver.

[0104] Figure 13c represents three positions of the vehicle assembly in Figure 13a from the moment it approaches the parking space at the start of the reversing maneuver.

[0105] Figure 14 represents two positions of the vehicle assembly as a continuation of the reverse parking maneuver represented in Figure 13c.

[0106] Figure 15 represents two positions as a continuation of the reverse parking maneuver shown in Figure 14.

[0107] Figure 16 shows a reverse parking maneuver position for a vehicle with three articulations. The references used in the figures are listed below:

[0108] 1. First element or tractor head.

[0109] 2. Intermediate element.

[0110] 3. Rear element.

[0111] 4. First joint.

[0112] 5. Second joint.

[0113] 6. Electronic control module.

[0114] 7. Actuator.

[0115] 8. Directional media.

[0116] 9. Interface.

[0117] 91. First selector, for ON / OFF activation.

[0118] 92. Forward / reverse gear indicator.

[0119] 93. Overdraft indicator.

[0120] 10. Articulation in directional media:

[0121] 101. Between wheels and axle.

[0122] 102. On pivoting spear.

[0123] 11. Left wheel of the intermediate element.

[0124] 12 Right wheel of the intermediate element.

[0125] 13. Entry position.

[0126] 14. Starting position.

[0127] 15. Initial rotated position.

[0128] 16. Intermediate rotated position.

[0129] 17. Final rotated position.

[0130] 18. Third joint.

[0131] 19. Second trailer

[0132] 20. Articulated lance.

[0133] DETAILED EXPLANATION OF THE INVENTION

[0134] The system that addresses the methodology proposed in the present invention is a directional control system for reversing maneuvers in a vehicle assembly with more than one joint. It falls under what is known in the industry as ADAS (Advanced Driver Assistance Systems) and is intended to be used for performing maneuvers at low speeds. It is, therefore, an alternative steering system to the one used on the road as the primary system. This system can be activated manually by pressing a button on an interface, or it can be parameterized so that when traveling in reverse and below a certain speed, it automatically comes into operation.

[0135] The simplest case that can be treated is a vehicle assembly with two joints.

[0136] The present detailed description of an embodiment of the invention refers, in accordance with the figures that accompany this description, to a directional control system for performing maneuvers of a vehicle assembly with two articulations by a user, where the vehicle assembly comprises the first element or tractor head (1) comprising a first articulation (4), an intermediate element (2), connected to the tractor head (1) by means of the first articulation (4), which comprises a second articulation (5) and a rear element (3), connected to the intermediate element (2) by means of the second articulation (5). In order for the intermediate element (2) to perform the functions of a virtual ball joint or articulation and to make the vehicle assembly work as if it only had one articulation, a system with the following elements is needed:

[0137] - have directional means (8) located in the intermediate element (2),

[0138] - having means for monitoring a first sensor, configured to detect a first relative position of the longitudinal axis of the tractor head (1) with respect to the longitudinal axis of the intermediate element (2), where the first relative position defines an angle a;

[0139] - having means for monitoring a second sensor, configured to detect a second relative position of the longitudinal axis of the intermediate element (2) with respect to the longitudinal axis of the rear element (3), where the second relative position defines an angle;

[0140] - have means to monitor a third sensor located on the wheels of the intermediate element (2) or a reverse signal from the tractor head (1), configured to detect when the direction of travel S is reverse, at which time the directional system can be activated;

[0141] - having actuating means (7) of the directional means (8), configured to modify a position of the directional means (8), where modifying the position of the directional means (8) results in a modification of the angle formed between the directional means (8) of the intermediate element (2) with respect to the longitudinal axis of the intermediate element (2) angle 5;

[0142] - have at least approximately the significant length dimensions of the vehicle assembly, for example, those shown in FIG. 1 , dimensions a, b, c, d, where a: distance between the center of the axes of the rear element and the second joint (5); b: distance between the axis / s of the intermediate element and the second joint (5); c: distance between joints; d: distance between the first joint (4) and the center of the rear axles of the tractor head;

[0143] - have an electronic control module (6), fed back with the angles a and p, with the data from a sensor that detects when the direction of travel S is in reverse, has the significant dimensions of the length of the vehicle assembly a, b, c, d, configured to: o determine the reference angles ar and pr, using a mathematical expression or directly a table of values ​​that relates the angles a and p and the dimensions a, b, c, d; so that, for each value of the angle a+p, a single reference value of these angles ar and pr is defined; these reference angles can also vary depending on the type of maneuvers that this vehicle assembly is going to perform. The angles ar and pr are those that make the vehicle assembly work as if it had only a tractor head (1) and a rear element (3),by relocating the intermediate element at these angles (2) it allows the three elements to roll along coherent paths and places the intermediate element in the appropriate place so that the turning requirements (angle 5) of the directional means (8) are minimal and, in addition, the spaces necessary for the maneuver are minimal; or depending on the relationship established between the angles a and p and taking into account the angles ar and pr, use a control algorithm to calculate the position that the directional means (8) must adopt, angle 5 and / or send a signal to the actuating means (7) of the directional means (8) to carry out this turn and thus modify angle 5 such that, as a result of modifying angle 5, the position of the directional means (8) forcibly produces a balance of forces that maintains the relative position of the assembly in accordance with the reference angles ar and pr,operating a vehicle assembly with two joints in reverse as if it only had one, since by means of the forced continuous repositioning of the intermediate element it functions as a virtual ball joint or joint between the first element and the rear element. In FIG. 1 a) a side view of a vehicle assembly with two joints (4) and (5) can be seen. In FIG. 1 b) that same vehicle assembly can be seen, circulating at that moment in its reference angular position ar and |3r, in which the three elements of the vehicle assembly are circulating along the same circular path (as it is the simplest and most common way to illustrate it, but there are multiple possible paths) while the tractor head (1) is turning a constant angle 0, in this case the values ​​of the angles a and p can be designated by means of a table or algorithm as reference angles ar and r.,

[0144] Depending on the type of vehicle assembly, its geometry and the maneuvers it is going to perform, the angles ar and pr may be located in some parts of the maneuver coinciding with its path, as is the case in FIG. 1, so that angle 5 = 0, the directional means will not turn and the turning of these directional means will only be used to change from one path to another or to correct deviations within that same path, as shown in FIG. 2 and FIG. 3.

[0145] In FIG.2 and FIG.3 the vehicle assembly is deviated from its reference angles, to recover its reference position, the control module (6) corrects its position by sending a signal to the actuating means (7) that rotate the directional means (8) by an angle 5 so that the reference angular position is recovered quickly, in FIG.2 the angle a is smaller than ar so the directional means (8) will rotate clockwise and in FIG.3 it is the opposite.

[0146] In many cases, due to the geometry of the vehicle assemblies and their need to maneuver in small spaces, different configurations must be made in some areas of the maneuver, for example, reference angles ar and Pr can be established as can be seen in FIG. 13 (c) position 14 and position 15, where at this moment of the maneuver, to start it, a position ar close to 0 is set. o(tractor (1) and intermediate element (2) aligned) and the entire turn is being carried out in this case with the steering means 5, in this case increasing the angle p as it moves backwards (see variation from position 14 where p=0°, to position 15, where p has increased considerably); that is, in this case a reference angle ar=0° is used in order to be able to carry out radical manoeuvres in the minimum possible space, partially skidding the wheels of the rear element, just as single-articulated vehicle assemblies manoeuvre, which is essential in very long vehicle assemblies that want to optimise space.

[0147] In another area of ​​the manoeuvre and for the final entry into the discharge opening, very different positions of ar and pr can be adopted to facilitate the manoeuvre, for example, aligning the steering means (8) with the rear element (3). Therefore, with this type of parameterisation, a table of values ​​is constructed, based on the angle turned by the tractor head 0 (if it can be estimated or known) or based on the turned angles a and / or p. For each value of these parameters, a value is assigned to ar and pr. Alternatively, the angles ar and pr can be obtained by means of an algorithm if, due to the type of parameterisation, it is simpler.

[0148] An example of parameterization is detailed below.

[0149] In the simplest case, only angles a and p are known, and the significant dimensions of length are unknown. A simple mathematical expression is established and a PID (Proportional, Integral, and Derivative) control method is used, such that the mathematical expression defining the target position is a = p / 2, as we will work with in this example with a PID; the error with respect to the target position is err = a - p / 2; and the PID algorithm for calculating the angle is φ = kp*err + k¡ ,í err dt + kd *derr / dt.

[0150] With a parameterization in the form of a table, with values ​​of the angles ar and pr, it can be represented as follows:

[0151] In the table above, the function a = p / 2 is reflected for all values, except for values ​​between 5 o and -5 o, which reflects a function a=p. This table is merely an example of parameterization, since the present invention allows the flexibility to modify certain values ​​in places where it is preferable due to the geometry or maneuvers to be performed by the vehicle groups, in a simpler way than with a mathematical expression, to achieve the relative position of interest at any given time.

[0152] As can be seen in this simple example, when using the mathematical relationship between angles, a = p / 2, if a PID controller is used, the error is err= a - p / 2, that is, as long as angle p is not double angle a, the error is non-zero and angle 5 is also non-zero, so the correction starts in one direction or the other. In this case, it has not been necessary to specify the angles ar and pr, as in the case of the tabular expression, where they are specified. Using the aforementioned algorithm, all the values ​​of a and p that result in err=0 will be the values ​​of ar and pr.

[0153] According to another example of parameterization, the values ​​of the angles a and P are available, as well as the significant dimensions of the length of the vehicle assembly (a, b, c, d). In this case, as shown in Figure 1 , the three elements of the vehicle assembly describe the same circular trajectory when 5=0. This is one of the parameterizations with the greatest maneuverability. Using trigonometric relationships with the help of FIG.1 , the algorithm to be used in this case is: tang a = (b+c+(d / cos a)) / h' tang p = ((a / cos P) - b) / h'; equating both expressions:

[0154] (b+c+(d / cos a)) / tang a = ((a / cos P) - b) / tang P; the error with respect to the target position if we use a PID control method is: err = (b+c+(d / cos a)) / tang a - ((a / cos P) - b)) / tang P; and the calculation of angle 5 using a classic PID control is as follows:

[0155] 5 = kp*err + k¡ J err dt + kd *derr / dt;

[0156] In both FIG.2 and FIG.3, as well as in FIG.13, the directional means are being operated “actively” to force certain positions, they are being rectified (FIG.2 and FIG.3) or positions are being maintained (FIG.13) in a forced manner, exerting significant stresses on the directional means. Mainly in cases such as that of FIG.13, in this specific case, the capacity to maintain lateral stresses of the directional means (8) of the intermediate element (2) is being used to maintain its position, in this case the axis of the directional means (8) placed in the reference position is able to maintain its position, based on the deformation of the tires FIG.13 (b).

[0157] The force that a wheel can withstand while maintaining its position before skidding is around 30% of the total weight that it is supporting in its normal position, so as an example, in a truck axle that when loaded can support up to 9 Tm, if this axle is performing the function as a directional means in the intermediate element (2), it could maintain a forced position supporting the lateral forces that can be generated by the rear element (3), the tractor head itself (1), the slopes of the terrain and other external forces of up to 2.7 Tm, maintaining its position and keeping the path. In FIG.13 (b) shows the deformation that is occurring in the tires due to the stresses they have to withstand so that the intermediate element (2) maintains a position aligned with the tractor head (1) and at the same time partially skids the tires of the rear element (2) to perform a maneuver in a reduced space, as is done by single-joint vehicle assemblies when the maneuvering space is similar.

[0158] FIG.13 b) shows a top-down view of a tire of a steered wheel of the intermediate element (2) and the footprint of that tire, the tractor exerting a thrust force F on the aforementioned tire that causes it to move forward, this force F produces a deformation in the tire that in turn generates a reaction force D in the tire that will compensate for the component of F perpendicular to the tire. This is what allows the wheel to describe a curved trajectory. Due to the deformation of the tire, this trajectory has a drift with an angle E between the tire and the wheel.

[0159] In the current case, there are also other external forces, Fext, the sum of the forces exerted by the intermediate element (2) and the rear element (3), the slopes of the terrain, potholes and other internal and external factors that tend to deviate the vehicle assembly from its path. In order, in this case, to keep the tractor head and the intermediate element aligned, an additional deformation must occur in the tire, generating a reaction force D' that will allow the wheel to compensate for the action of the total sum of Fext to maintain the trajectory. This new deformation of the tire will produce an additional drift with an angle E' that will be added to E to obtain the total drift.

[0160] The drift angle of a wheel generally varies between 0 o to 5 o . With a drift angle of 5 o, a vehicle wheel is capable of exerting a perpendicular force on the tire of around 30% of the total weight it is supporting, so with a slight variation in the drift angle it is possible to generate a large torque in the intermediate element (2) with the aim of counteracting all the external forces already mentioned.

[0161] In this way, the tires of the steered wheels are being made to act in an “active and forced” manner, which, by means of a slight variation in the angle 5, are able to adjust to the new drift angle and are able to maintain the balance of forces at all times and, consequently, maintain forced trajectories in maneuvers with little space. This “active and forced” action of the steered means (8) is another major difference with the current state of the art.

[0162] In FIG.9(a)-9(c) three different positions of the intermediate element (2) are shown for the same total angle a+p= 65° between the tractor head (1) and the rear element (3). Evidently the different positions of the intermediate element are infinite for each different angle a+p in a vehicle assembly without any intervention of an electronic control system.

[0163] In the present invention, for each different angle a+p a single reference position ar, pr is assigned, FIG.9 (d), which is why the intermediate element acts as a virtual ball and socket joint FIG.9 (e) and FIG.10 (a)-10(e); since, functionally, the two joints that the intermediate element has are converted into a single one.

[0164] With different parameterizations, this unique reference position of the intermediate element may vary, but in any case it will always be unique for each possible parameterization.

[0165] FIG. 10 shows one of the possible parameterizations of a vehicle assembly with two joints, where the different reference angles adopted by the vehicle assembly are shown depending on the trajectory marked by the driver, for example, in 5 different positions. It can be seen that angle 5 varies depending on the relative position of the three elements and can be 0 o or a different value, as in figures FIG.10 (b) and (d) which is set at -10° and 10° respectively, depending on the geometry and maneuvering needs of the vehicle assembly.

[0166] Regarding the control algorithm, there are several known control methods that can be used to determine an algorithm that guarantees optimal system performance. Some of the methods that can be used to establish this algorithm for calculating angle 5 (although there are many others) are the PID (Proportional, Integral, and Differential) control method or the LQR (Linear Quadratic Regulator); since the system operates at low speeds, in principle, any of these methods or control strategies would be valid for ensuring proper system performance.

[0167] The PID control method is the most used and simplest in control electronics, because the system requirements are not very large mainly due to the low operating speed of the system, in this case it may be one of the most suitable to perform the angle correction function 5.

[0168] In another embodiment of the invention, it is contemplated that the electronic control module, in addition to being fed back with the angles a, p, has the significant dimensions of the length of the vehicle assembly and, additionally, is also fed back with the angle 5, as seen in FIG. 5, which can be obtained directly from the directional means or by a rotation sensor arranged in the intermediate element, has a fifth sensor V that, in addition to detecting the direction of travel, measures the speed of the intermediate element (2). This direction and speed sensor can be located in the intermediate element or can be obtained, in some cases, from the tractor head.

[0169] In this way, the electronic control module, based on the values ​​provided by a, 5 and V, the significant length measurements (b, c, d, e), where e is the distance between the axles of the tractor head (in the case of several rear axles, it is measured from the center of the rear axles), and using geometric relationships and calculations based on the variation of a with respect to the position of 5 in a unit of space, estimates the angle at which the steering axis of the tractor head is turning (angle Qest). This together with the rest of the parameters, are used to obtain the value of the angles ar and |3r more quickly, and to improve the algorithm for calculating angle 5, since when estimating angle 0, the system reacts more quickly (as if it were reading angle 0 turned by the tractor and not rectifying once deviations occur). In this way, the range of movement of 5 is reduced by greatly reducing the uncertainty about the position of 0 and improving the operation of the system. Therefore, the control algorithm (PID, LQR or similar) only acts on deviations from a better initial position and, above all, with greater anticipation. It will be a system with smaller range movements of the actuating means (7), which reduces the need to turn the directional means (8).

[0170] To do this, according to FIG. 1 and continuing with the example of a vehicular assembly in which its three elements are forced to follow a circular path, the angle 0 is established using trigonometric relationships as a function of a and the significant dimensions of length: tang 0 = e / h; tang ar = (d + (b+c) / cos ar) / h; equating both expressions; e / tang 0 = (d + (b+c) / cos ar) / tang ar;

[0171] 0= are tang ((e tang ar) / (d + (b+c) / cos ar)).

[0172] Continuing with this parameterization example, in FIG.7, the tractor head (1) and the intermediate element (2) can be seen moving backwards a space Ay, (a single tire has been placed in the center as a simplification of the system). In FIG.7 a) we have a position of the steering wheel of the tractor head 0, with the intermediate element located at an angle a with respect to the tractor head and with a turn 5 of the directional means, the position of the steering wheel is turned to 0', so that when moving forward the space Ay, as observed in FIG.7 b), the angle a becomes a greater angle a' and the angle 5 becomes 5'.

[0173] From the geometric relationships represented in FIG.7, the following relationships can be obtained:

[0174] Ay- unit of space displaced backwards by the vehicle set;

[0175] Ax - lateral deviation with respect to the previous trajectory measured at the start of the tractor head (the previous trajectory is the one it was tracing before advancing Ay);

[0176] Ax'- lateral deviation from the previous trajectory measured at the end of the tractor head; tang (0- 0') = Ax / Ay;

[0177] Ax'=Ax d / e; tang(a+ 5 - a'- 5')= Ax' / cos(a) (b+c);

[0178] Ax= e (b+c) / d tang(a+ 5 - a'- 5') cos(a);

[0179] A 0= 0 - 0' = arctang (e (b+c) / d tang(a+ 5 - a'- 5') cos(a) / Ay).

[0180] In FIG.1, we now also search for trigonometric relationships of the angle ar as a function of 0, as follows: ar= arctang ((b+c) / h') + arctang (d / h); tang 0 = e / h; by substituting and equating, we arrive at the following expression: ar= arctang ((b+c) / (e / tang 0)2+d2-(b+c)2) + arctang (d tang 0 / e)

[0181] Using the equation derived above and replacing the value a, the value of 0 is obtained:

[0182] 0= are tang ((e tang ar) / (d + (b+c) / cos ar)); Replacing the value of 0 obtained in the previous step and the rest of the values ​​we have, we will also obtain the value of A 0:

[0183] A 0= 0 - 0' = arctang (e (b+c) / d tang(a+ 5 - a'- 5') cos(a) / Ay)

[0184] Finally, 0est= 0 + A 0.

[0185] With the value of 0est, the reference angles ar and |3r are calculated using the expressions shown above, which allows the control algorithm to be established in a more precise and reactive way,

[0186] 5= kp*err + k¡ J err dt + kd *derr / dt;;

[0187] In this way, the values ​​of the coefficients kp, k¡, and kd can be reduced to optimize the performance of the PID control system. The speed sensor V is required to measure the feed rate Ay.

[0188] Additionally, in countries where legislation permits it, the invention contemplates that the electronic control module, in addition to being fed back with the angles a, p, having the reverse signal S and the significant dimensions of the length of the vehicle assembly (a, b, c, d, e), actually has the angle 0 provided by the tractor head, as observed in the block diagram of FIG. 6. Thus, the angle 0 replaces the estimated value 0est in the estimates of the previous paragraph.

[0189] The driver controls this two-articulated vehicle the same as if it had only one joint. If, for example, the steering wheel is turned to the left while in reverse, the rear element will turn right, and the middle element will automatically position itself at its target angles r and r, without any operational influence on the vehicle's handling. Therefore, the driver must pay attention only to the tractor unit and the rear element, as with single-articulated vehicles; the same applies when turning right or performing other types of maneuvers.

[0190] The first sensor, according to different embodiments of the invention, is contemplated to be either a rotation sensor, configured to directly detect the angle a; or a distance sensor, configured to indirectly detect the angle a based on the distance detected between the first element (1) and the intermediate element (2).

[0191] The second sensor, according to different embodiments of the invention, is contemplated to be either a rotation sensor, configured to directly detect the angle P; or a distance sensor or similar, configured to indirectly detect the angle p based on the distance or position detected between the intermediate element (2) and the rear element (3).

[0192] The reverse operation, according to different embodiments of the invention, can be detected either by taking this signal from the tractor head (1), or by means of a third kinematic sensor located on the wheels of the intermediate element (2).

[0193] The fourth sensor, according to different embodiments of the invention, is contemplated to be either a rotation sensor, configured to directly detect angle 5; or a travel sensor of a hydraulic cylinder of the actuating means, configured to indirectly detect angle 5 based on the travel of the hydraulic cylinder.

[0194] The fifth sensor, according to different embodiments of the invention, is contemplated to be a kinematic sensor located on the wheels of the intermediate element (2) capable of measuring the direction of travel and speed of the intermediate element (V), and may also be obtained directly in some cases from the tractor head.

[0195] The first element is selected from: a tractor head or truck in the case of two-articulated vehicle combinations or between a dolly or first axle type vehicle element, or a trailer or semi-trailer type vehicle in the case of a three-articulated vehicle combination.

[0196] The intermediate element and the rear element are selected from: a dolly or first axle type vehicle element, or a trailer or semi-trailer type vehicle, depending on the configuration or whether the vehicle assembly has two or more joints.

[0197] FIG.11(a) - 11(f) show some examples of intermediate elements (2) of a vehicle assembly (vehicles or vehicle elements) where this system can be implemented.

[0198] (a) Dolly (2) (vehicular element): consists of a double steering axle located at the rear, a fifth wheel as a coupling mechanism and a traditional hook as a hitch mechanism.

[0199] (b) Semi-trailer (3) coupled to a dolly (2) as shown in Figure 11(a)

[0200] (c) Link-trailer (2) (vehicle), has two steering axles at the rear of the vehicle and can be coupled at the front with a tractor head and at the rear with a traditional semi-trailer.

[0201] (d) First trailer axle (2) (vehicle element): similar to that of figure 11(a), although with a single steering axle.

[0202] (e) Split axle trailer (3)(vehicle), with the first axle (2) of figure 11(d) coupled.

[0203] (f) Central axle trailer (2) (vehicle): it has a hook for coupling at the front and another hook at the rear. The steered axles are also towards the rear of the vehicle. The intermediate element (2) incorporates steered means. The steered means (8) to be used are those currently on the market, where there are various technical solutions and manufacturers offering them. The two most commonly used solutions today may consist of steered axles, that is, axles located in a rotating crown whose wheels do not rotate with respect to the longitudinal axis, or axles with steered wheels, where the axle is fixed and it is the wheels that rotate with respect to the longitudinal axis (as is the case with the steered means used in FIG. 2 and FIG. 3.

[0204] The wheels of these directional axles are oriented by means of actuators (7), mainly hydraulic, which will position the wheels at the appropriate angle 5 at all times with respect to the longitudinal axis of the intermediate element (2).

[0205] The fact of having steered axles in the intermediate element (2) can be used for reversing in two different ways: normal forward rolling on the road, its use is for passing roundabouts and tight curves at speeds lower than around 40 km / h, where they are controlled by a main steering system with a specific program, generally from the manufacturer of the steered axles; at higher speeds, they remain fixed without pivoting in their initial position; or rolling in reverse maneuvering mode, when reverse gear and low speeds are detected, it is activated either manually by the driver or automatically if so configured, the electronic control module (6) will take control of the actuating means (7) of the steered axles (8) as explained above.

[0206] The electronic control system (6) in charge of data processing uses angle 5 as input data, with the adjustment rule used by each axle manufacturer to process this angle. As is known, in a set of directional axles there are several wheels and each one will have a slight angle offset with respect to the others depending on the position of each of them in the vehicle assembly, normally following the Ackerman principle, which indicates that each of the wheels of a vehicle assembly have the same center of rotation.

[0207] In another preferred embodiment of the invention, the directional means FIG. 12 (b) are constituted by an articulated lance (20). The articulated lance (20) is located between the first joint (4) and the joint (102) that joins this lance (20) and the intermediate element (2). This configuration has two rotation sensors located as follows: the first sensor in the first joint (4), configured to detect the angle formed between the longitudinal axis of the tractor head with respect to the articulated lance (20), angle w; and the second sensor located in the joint (102) that joins the lance (20) to the intermediate element (2), configured to detect the angle formed between the articulated lance (20) and the longitudinal axis of the intermediate element, angle ip.

[0208] As can be seen in Figure 12 (b), the total rotation of the steering means, i.e. the angle formed between the longitudinal axis of the tractor head with respect to the longitudinal axis of the wheels of the intermediate element, angle a + 5, is equivalent to the sum of the rotations measured in the two aforementioned sensors, angles w+ ip. Such that: a + 5= ÜJ+ ip.

[0209] In order to parameterize directional means consisting of a pivoting lance and knowing the length of the pivoting lance (f) and the distance (g) between the joint (102) and the second joint (5) represented in FIG. 12(b), the corresponding geometric equations are established that relate the angles a and 5 as a function of ÜJ and ip.

[0210] It should be noted that in the case of having a pivoting lance, the longitudinal axis of the intermediate element (2) is considered to be a straight line that passes through the two joints (4) and (5) that are in the intermediate element, with respect to this straight line the angles a, p and 5 are measured, as represented in FIG. 12 (b).

[0211] Each wheel has an associated sensor that measures its speed V(11) and V(12). The electronic control module, with the speed values ​​V(11) and V(12), manages the difference in rotation speed of both wheels necessary to vary the angle 5.

[0212] In the case of using a pivoting lance there are several possibilities as actuating means (7):

[0213] Use independent motorized wheels (11, 12) in the intermediate element (2) that by means of their rotation at different speeds V(11) and V(12), perform their function as actuators. Use independent brakes on each wheel (11, 12) in the intermediate element (2) that by means of their reduction in rotation due to braking on one of the wheels perform their function as actuators.

[0214] Use hydraulic cylinders (7) located on the lance as actuators.

[0215] Use a combination of the above.

[0216] In the case of a traditional lance FIG.12 (a) it is also possible to use independent motorized wheels (11, 12) in the intermediate element (2) which, by rotating at different speeds V(11) and V(12), perform their function as actuators.

[0217] The interface (9) between the directional system of the present invention and the driver shown in FIG. 8, in one of the embodiments of the invention, can be constituted in a screen that will be in the driver's cabin, with the different commands and options that the driver has, it can be used and viewed from any mobile phone or electronic device, which can be connected wirelessly with the directional system of the intermediate element.

[0218] The connection between the steering system and the driver's mobile device can be achieved by scanning a QR code, using Bluetooth, Wi-Fi, the internet, or any other means currently available.

[0219] The intermediate element can have a specific wireless or wired connection screen that acts as a backup in case of problems connecting to the driver's mobile device.

[0220] On the screen in FIG. 8, you can see the basic functions that this device can offer.

[0221] First selector (91), for the activation of the directional control system for maneuvers.

[0222] Forward / reverse gear indicator (92).

[0223] Overturn indicator (93), right or left, by the driver.

[0224] If the indicators (92,93) flash and emit beeps, the driver must slow down and follow the arrows to regain the correct position of the system. The interface provides the ability to input significant length values, a, b, c, d, e values ​​and the rotation limits of the actuators (7) 5max and órnin.

[0225] Obviously, this remote control can include many other functions that can aid in maneuvering, such as a fault indicator, rearview cameras, graphics indicating the vehicle's position, and others that can help with reversing.

[0226] Figures 13, 14, and 15 show how the entry maneuver into a discharge inlet of a bi-train or vehicle combination with two articulations (4, 5) is performed in three consecutive steps. Specifically, it is an entry maneuver into a discharge inlet at 90° between two trailers parked in adjacent inlets with little space to perform it, which is one of the most complicated maneuvers that can be encountered in real life.

[0227] Whenever possible, the maneuver is performed on the driver's side, turning left (avoiding the blind spot that occurs with a right-hand maneuver), since from that side the driver, looking out the window and using the rearview mirrors, will have a clear view of the discharge chute and the vehicle.

[0228] The entry maneuver into the unloading mouth of this vehicle set (25 m long bi-train) will be carried out as follows:

[0229] Today, trucks of this type require at least 30 meters of clearance in front of the discharge opening. A highly experienced driver is required to perform this maneuver. The driver must fully align the vehicle and then carefully reverse the vehicle and make repeated small corrective maneuvers to ensure the vehicle remains aligned as it approaches the discharge opening.

[0230] By using the directional system of the present invention, as seen in Figures 13, 14, and 15, the most complicated maneuver of entering the discharge opening is performed in a space in front of the discharge opening of approximately 12.5 meters, similar to the minimum distance required by a single-articulated trailer under these same circumstances. The maneuvers are simple and rapid, due to the great maneuvering capacity already explained. The movement is performed in one go and without corrections.

[0231] In vehicle assemblies with three joints, two systems can be used, one between the first (4) and second (5) joint and another between the second (5) and the third FIG.16 (18) in order to manage the three joints so that the vehicle assembly functions as if it only had one.

[0232] Another possible strategy for vehicle assemblies with three articulations is the use of the directional maneuvering system only between the second (5) and the third articulation (18) in order to operationally move from a vehicle assembly with three to two articulations, thus at least simplifying the handling difficulty, without incurring such a high cost, provided that there is sufficient space for the handling of a vehicle assembly with two articulations.

[0233] In FIG.16, we will have this last case represented, with a first free joint (4) and the directional system located between the second (5) and the third joint (18), managing the movement between the rear element (3) and the second trailer (19).

Claims

CLAIMS 1. Directional control system for performing reverse maneuvers of a vehicle assembly with more than one joint (4, 5) by a user, where the vehicle assembly comprises a tractor head (1) comprising a first joint (4), an intermediate element (2), connected to the tractor head (1) by means of the first joint (4), comprising a second joint (5) and a rear element (3), connected to the intermediate element (2) by means of the second joint (5), the system being characterized in that it comprises: directional means (8) located in the intermediate element (2), a first sensor, configured to detect a first relative position of the longitudinal axis of the tractor head (1) with respect to the longitudinal axis of the intermediate element (2), where the first relative position defines an angle a;a second sensor, configured to detect a second relative position of the longitudinal axis of the intermediate element (2) with respect to the longitudinal axis of the rear element (3), where the second relative position defines an angle p; a third sensor configured to detect a direction of travel S of the vehicle assembly in reverse; actuating means (7) of the directional means (8), configured to modify a position of the directional means, where modifying the position of the directional means results in a modification of an angle 5 defined between the directional means of the intermediate element with respect to the longitudinal axis of the intermediate element;an electronic control module, fed back with the angles a and p, where in case of detecting a direction of travel S reverse, it is configured to determine a pair of reference angles ar and pr unique for each value of the sum a+p calculate a value for angle 5 that maintains the angles a and p at the reference values ar and pr; and send a signal to the actuating means (7) of the directional means (8) to modify the position of the directional means placing them at the calculated value of angle 5, such that, as a result of forcibly maintaining, by the directional means, the relative position of the intermediate element (2) at the reference angles ar and pr, the operation of a vehicular assembly with a single joint is simulated.; 2. System according to claim 1, wherein the electronic control module is additionally configured to receive significant values of the length of the intermediate element and rear element, distances between axles and distances between axles and joints; and to calculate the value of angle 5 based on said values.

3. System according to any of claims 1 and 2, wherein the system additionally comprises: a fourth sensor configured to detect the angle 5 defined between the directional means of the intermediate element with respect to the longitudinal axis of the intermediate element; and a fifth sensor configured to detect the direction and speed of rotation of the wheels of the intermediate element; where the electronic control module is also fed back with the angle 5, detected by the fourth sensor, and the direction and speed of rotation, detected by the fifth sensor, and where the electronic control module is also configured to estimate a turning angle of directional means of the tractor head (1), defined as angle 0est, based on geometric relationships between angle a, angle 5 and direction and speed of rotation of the wheels of the intermediate element.

4. System according to any of claims 1 and 2, wherein the electronic control module is further configured to receive from the tractor head (1) a turning angle 0 of directional means of the tractor head (1) 5. System according to claim 2, further comprising: an interface between the electronic control module and the user, configured to feed the electronic control module with significant values of the length of the vehicle assembly, distances between axles and distances between axles and joints.

6. System according to any of the preceding claims, further comprising: an interface between the electronic control module and the user, with at least one on / off indicator (9.1), a forward / reverse indicator (9.2) and an over-rotation indicator (9.3), configured to establish rotation limits of the actuators (7) (omax and omin) in the electronic control module; where the electronic control module is further configured to compare the received values of angle 5 with the established limit values omax and omin and, depending on the comparison, sends an activation signal to the overshoot indicator (9.3).

7. System according to any of the preceding claims, wherein all the sensors that supply power to the electronic control module, the actuators, the directional means and the electronic control module are arranged in the intermediate element, where the intermediate element is independent from the rest of the elements of the vehicle assembly.

8. System according to any of the preceding claims, wherein the directional means (8) comprise an axle and a pair of motorized wheels (11, 12) configured to pivot, each, at a point (101) between its rim and the axle; where the actuators (7) of the directional means comprise motor means configured to motorize each wheel (11, 12) independently and a sensor configured to detect their independent rotation speeds V(11) and V(12); and where the electronic module is also configured to estimate a difference in rotation speed between the motorized wheels that causes the modification of the position of the directional means, until reaching the calculated value of angle 5; and send the corresponding signal to the actuator means.

9. System according to any of the preceding claims, wherein the directional means (8) comprise a pivoting lance, where the intermediate element (2) is configured to pivot with respect to the pivoting lance at a point (102); where the actuators (7) of the directional means comprise motor means configured to motorize each wheel independently (11) and (12) and a sensor configured to detect their independent rotation speeds V (11) and V (12); and where the system also comprises: two rotation sensors at the junction between the lance and the tractor head (4) and the pivot between the lance and the intermediate element (102) respectively; and where the electronic module is also configured to estimate a difference in rotation speed between the motorized wheels that causes the modification of the position of the directional means, until reaching the calculated value of angle 5; and send the corresponding signal to the actuator means.

10. Directional control method for performing reverse maneuvers of a vehicle 1. A vehicle assembly comprising more than one joint (4, 5) for a user, wherein the vehicle assembly comprises a tractor head (1) comprising a first joint (4), an intermediate element (2), connected to the tractor head (1) by means of the first joint (4), comprising a second joint (5) and a rear element (3), connected to the intermediate element (2) by means of the second joint (5), the system being characterized in that it comprises the following steps: detecting, by a first sensor, a first relative position of the longitudinal axis of the tractor head (1) with the longitudinal axis of the intermediate element (2), where the first relative position defines an angle α; detecting, by a second sensor, a second relative position of the longitudinal axis of the intermediate element (2) with respect to the longitudinal axis of the rear element (3), where the second relative position defines an angle P;detect, by a third sensor, a direction of movement S of the vehicle assembly in reverse; receive, by a feedback control module, the angles a, p and the detection of reverse gear S; determine a pair of reference angles ar and pr unique for each value of the sum a+P; calculate a value for an angle 5, defined by the directional means of the intermediate element with respect to the longitudinal axis of the intermediate element, which maintains the angles a and p at the reference values ar and pr; send, by the electronic control module (6), a signal to the actuating means (7) of the directional means (8) to modify the position of the directional means to the value calculated for the angle 5, such that, as a result of forcibly maintaining by the directional means the relative position of the intermediate element (2) at the reference angles ar and pr, the operation of a vehicle assembly with a single joint is simulated.

11. Method according to claim 10, further comprising detecting, by a fourth sensor, the angle 5 defined between the directional means of the intermediate element with respect to the longitudinal axis of the intermediate element; detecting, by a fifth sensor V, the direction of travel and the speed of rotation of the wheels of the intermediate element; estimating, by the electronic control module, a rotation angle of some directional means of the tractor head (1), defined as angle Qest, based on some geometric relationships between angle a, angle 5, and the direction and speed of rotation of the wheels of the intermediate element; and modify the calculation of the value of angle 5 according to the value of angle Qest.

12. A method according to claim 10, further comprising: receiving, by the electronic control module, from the tractor head (1), a turning angle 0 of directional means of the tractor head; and modifying the calculation of the value of angle 5 according to the detected value of angle 0.

13. A method according to claim 11, further comprising: feeding the electronic control module, via a user interface, with significant values of vehicle assembly length, wheelbase, and distances between axles and joints; and modifying the estimate of angle 0est, reference angles r and r; and calculating the value of angle 5, according to the values provided by the interface.

14. Method according to any of claims 10, 11, 12 and 13, further comprising: feeding the electronic control module, from a user interface, with rotation limits of the actuators (7) (omax and omin); comparing, in the electronic control module, the values received from angle 5 with the limit values omax and omin; and sending, from the electronic control module, based on the comparison, an activation signal to an over-rotation indicator (9.3) of the interface.

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