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TECHNICAL FIELD

The invention concerns a work vehicle, in particular a wheel loader.

BACKGROUND OF THE INVENTION

As commonly known, work vehicles and especially wheel loaders are designed to carry out several different kinds of activities .

Just to set out some examples, a wheel loader is typically configured to carry out the following activities:

- truck loading, i.e. removing bulk materials by throwing it on a truck;

- hauling, i.e. transporting a load across a jobsite;

- pick and place, i.e. pick and lift material and then place it at a destination on the ground or on a shelf;

- stock piling, i.e. defining a stockpile of bulk materials at a storage location.

Each of the activities generally requires different ways of driving the work vehicle; therefore, a driver usually adapts the way of driving the work vehicle based on the activity to be carried out.

However, there is a need for adapting the way of driving the work vehicle in a more efficient and repeatable manner, as well as for increasing the comfort and safety of the driver while correspondingly decreasing the number of the operations that the driver should carry out for adapting the way of driving .

More precisely, there is also a need for simplifying the adaptation, in particular by adjusting only a minimum number of settings, without jeopardizing the effectiveness of the adaptation .

An object of the invention is to satisfy at least one of the above-mentioned needs , preferably in a simple and cost saving manner .

SUMMARY OF THE INVENTION

According to the invention, the obj ect is reached by a work vehicle as defined in claim 1 .

Dependent claims set out particular embodiments of the invention .

BRIEF DESCRIPTION OF DRAWINGS

For a better understanding of the invention, speci fic embodiments will be described in the following, by way of nonlimiting examples , with reference to the attached drawings wherein :

- Figure 1 is a lateral view of a work vehicle , according to the invention;

- Figure 2 is a perspective view of a keypad within a cab of the work vehicle ;

- Figure 3 is a front view of an instrument panel inside the cab ; and

- Figure 4 is a perspective view of a command device within the cab .

DETAILED DESCRIPTION OF THE INVENTION

Re ference number 1 in Figure 1 indicates a work vehicle , speci fically a wheel loader .

Vehicle 1 comprises a chassis la, in turn comprising a portion defining a cab lb for allowing a driver entering into vehicle 1 .

Vehicle 1 advances by means of a plurality of wheels 2 , which are suitable for operating in contact with soil , but this is not limitative ; other propulsion elements , such as tracks may be suitable .

Vehicle 1 comprises an engine 3 and optionally a hydrostatic transmission 4 as an actuator means to take power from the engine 3 and drive the wheels 2 with this power.

Of course, even the engine 3 is to be considered an actuator means, due to its function of driving movable members, in particular at least one component of the hydrostatic transmission 4.

Furthermore, vehicle 1 optionally comprises a mechanism 5 for carrying out a plurality of activities, like those listed above, with reference to the background of the invention.

With detail, mechanism 5 comprises a pivotal arm 6, which is hinged to the chassis la about an axis, specifically horizontal and transverse to an advancing direction of vehicle 1.

Preferably, mechanism 5 further comprises a tool 7, specifically a bucket, which is coupled to arm 6 in an orientable manner with respect to arm 6. More specifically, tool 7 is hinged to an end portion of arm 6 about a further axis, in particular parallel to the former axis.

Vehicle 1 comprises further actuator means to drive the mechanism 5; in particular, vehicle 1 comprises a first actuator device 8, such as one or more hydraulic cylinders, to drive arm 6 and, more in particular, a second actuator device 9, such as one or more hydraulic cylinders, to adjust the orientation of tool 7, with respect to arm 6.

Therefore, mechanism 5 defines a manipulator, specifically of the serial type, more specifically with one or more links arranged in series, with the first link hinged to the chassis la and any successive link hinged to the preceding one, the last link ending with tool 7 as end-effector.

Moreover, vehicle 1 further comprises at least one hitch, more precisely a front hitch 10 and a rear hitch 11 for the attachment of respective implements to vehicle 1.

Further actuator means of vehicle 1 are actuator devices 12, 13, like hydraulic cylinders, configured to raise and lower the hitches 10, 11, respectively.

More in general, hitches 10, 11, mechanism 5, wheels 2, and some components of the hydrostatic transmission 4 (e.g. a pump impeller) defines movable elements of vehicle 1, specifically with respect to the chassis la.

Vehicle 1 further comprises a control apparatus for controlling the actuator means of the same vehicle 1, including hydrostatic transmission 4, the engine 3, and each of the actuator devices 8, 9, 12, 13, in an independent manner with respect to each other.

Here, all the actuator means, except the engine 3, are all hydraulic actuators, but this is in not limiting; even actuators of other kinds may be suitable, like pneumatic or electric actuators.

The control apparatus comprises a determination unit 14 and a control unit 15, which may actually form part of a single computer or logic unit, or be interconnected separated logic units .

The control unit 15 is configured to control vehicle 1, in particular the actuator means, independently including the engine 3, the transmission 4, and the devices 8, 9, 12, 13.

The determination unit 14 is configured to determine one or more operative parameters that are indicative of an actual operation of the actuator means.

For example, the determination unit 14 comprises one or more transducers configured to detect respective quantities that correspond to the operative parameters. Alternatively or additionally, the determination unit 14 may comprise an observer, e.g. a deterministic or stochastic observer, to estimate the operative parameters, for instance based on the quantities detected by the transducers or based on information already contained into control unit 15, e.g. concerning the control of vehicle 1 or of the actuator means.

The operative parameters more specifically comprise quantities being each indicative of a motion of one of the movable elements driven by the actuator means.

In particular, the operative parameters comprise kinematic quantities, like one or more of a position, speed, and acceleration of one or more of the movable members, e.g. of one or more of arm 6, tool 7, components of the hitches 10, 11, wheels 2, components of the hydrostatic transmission 4, an output shaft of the engine 3, and the like, possibly including one or more of the position, speed, and acceleration of vehicle 1, more precisely with respect to the soil.

Alternatively or additionally, the operative parameters might also comprise dynamic quantities, such as torques or forces applied onto one or more of the movable members.

Moreover, the operative parameters might also comprise environmental quantities being indicative of a state of the environment around vehicle 1. Example of those environmental quantities may be temperatures, humidity, pressures, and the like, or quantities concerning a status of the surface on which vehicle 1 moves (dirt road, cobblestone, wet or dry asphalt, etcetera) . Indeed, environmental quantities influence the operation of the actuator means. Actually, for example, the way of driving vehicle 1 may be adapted as a function of the environmental quantities, for example in order to maximize driving performances.

Control unit 15 is configured to acquire the determined operative parameters from the determination unit 14.

Then, control unit 15 is configured to associate the determined or acquired operative parameters to control parameters of the actuator means, where the control parameters affect the promptness, responsiveness, or, using a more practical expression, aggressiveness of the actuator means.

More precisely, the associated control parameters are optimal parameters, namely parameters satisfying predetermined requirements. Here , the promptness is particularly intended as the speed with which any of the actuator means actually achieves , considering a reasonable approximation level , a reference motion of the corresponding controlled movable element of the vehicle 1 .

The reference motion, which can also be expressed as a set motion, may come from a request of the driver or from an optimi zation according to an optimi zation criterion .

Control unit 15 is also configured to control each of the actuator means according to a control law, which may be a feedforward or a feedback control law . This actually means that control unit 15 is configured to output command signal s for controlling the actuator means .

In particular, the control parameters are adj ustable parameters of one or more of the control laws .

For example , assuming a classical control law, i . e . a PID control law, e . g . for the position and/or the speed of one of the movable members , the typical gains of the PID control law may define some or all of the control parameters . In particular, the derivative gains are strongly correlated to the promptness of the controlled means , in response to the command signals of the control unit 15 . A simi lar situation occurs in case of a modern state-space control law, where the relevant gains may define the control parameters as well .

Control unit 15 associates the operative parameters to the control parameters according to a mathematical model , which may be for example stored or comprised by control unit 15 .

Speci fically, the mathematical model is learned by control unit 15 . This means that control unit 15 is configured to learn the mathematical model from at least the determined or acquired operative parameters . Speci fically, control unit 15 uses a machine-learning algorithm to learn the mathematical model .

In particular, the mathematical model is learned in advance and stored on control unit 15. However, this is not limitative; a continuous self-learning is also appropriate. Nonetheless, the mathematical model might be even not learned by control unit 1, but identified in advance according to known identification methods from experimental data.

For example, the mathematical model is learned by training a neural network, where the inputs are specifically the operative parameters.

The outputs of the neural network may be directly the control parameters. Similarly, according to a preferred alternative, the outputs are a plurality of variables defining a set of classes, where each class is particularly defined by a set of operating conditions of vehicle 1, e.g. identified by values of a state vector of vehicle 1, conveniently corresponding to a specific kind of activity, e.g. one of the listed activities with reference to the background of the invention .

Then, according to the mathematical model, each class may be associated to corresponding values of the control parameters. Specifically, this predefined association is based on experience, for example of the Applicant or of the driver, or of an expert. However, this is not limitative; indeed, the association may be the result of an optimization, for example carried out by using optimization techniques, such as linear or non-linear programming, or by solving an optimal control problem, or by means of stochastic or even heuristic techniques .

According to the invention, vehicle 1 further comprises a reporting device 20 (Figure 3) and a command device 21 (Figure 4) . In particular, the reporting device 20 and the command device 21 are configured to allow the driver interacting with the control of the actuator means.

The reporting device 20 is configured to provide the driver with information concerning the optimal control parameters associated by the control unit 15 to the operative parameters, according to the above-mentioned mathematical model .

The reporting device 20 is preferably arranged within the cab lb.

Specifically, the reporting device 20 comprises a display 22, as shown in Figure 3. The reporting device 20 may comprise additionally or alternatively any member suitable for presenting information to the driver, such as a speaker. Therefore, the information concerning the optimal control parameters may be visual, auditory, or a combination of visual and auditory information. For example, the speaker and the display may respectively announce and show the optimal control parameters. Even attic and/or tactile information may be considered as information provided by the reporting device 20 to the driver.

The command device 21 preferably comprises a plurality of command members 23, 24, 25, 26, that are respectively operable by the driver to send a plurality of different input signals to control unit 15. However, this is not limitative; indeed, the command device may comprise one or more single command members being each operable to send different input signals. Possibly, the command device 21 may just even comprise only the command member 23 being operable to send just one input signal to the control unit 15.

Preferably, the command device 21 is arranged within the cab lb.

For example, as shown in Figure 4, the command device 21 comprises a joystick or a control lever, to which the command members 23, 24, 25, 26 are coupled. In particular, command members 23, 24, 25, are respectively defined by buttons, and command member 26 is defined by a lever.

However, this is not limitative; each one of the command members 23, 24, 25, 26 may comprise a vocal receiver, such as a microphone. In this case, said one of the command members 23, 24, 25, 26 is operable by the driver via vocal commands to send the corresponding input signal or each of the corresponding input signals.

Control unit 15 has a first control mode, according to which it is configured to verify if a first specific condition is satisfied and to carry out or to carry out and then hold an adjustment of the promptness of the actuator means according to the optimal control parameters associated to the determined operative parameter, only if the first specific condition is verified to be satisfied.

In other words, control unit 15 modifies the promptness of the actuator means only after having verified that the first specific condition is satisfied.

The first specific condition is defined by the reception of a first input signal by the control unit 15. In particular, the first input signal is sent to the control unit 15 by means of command member 23.

Therefore, control unit 15 adjusts the promptness of the actuator means only if the driver has operated the command member 23 to send the first input signal, i.e. if the driver has agreed with the adjustment.

In particular, control unit 15 adjusts the promptness immediately after having received the first input signal.

In this sense, it is worth mentioning that the driver is informed about the control parameters to be set through the reporting device 20, such that the driver can agree with an according adjustment of the promptness of the actuator means by the control unit 15, in particular by operating the command member 23 to send the first input signal.

Here, according to the first control mode, control unit 15 is configured to control the reporting device 20, such that the latter provides the driver with the information concerning the control parameters to be set, i.e. the optimal control parameters .

Then, the driver can express an agreement by operating the command member 23, after having received the information from the reporting device 20.

The information may be also in the form of a loudly spoken question, which might be for example: "do you agree with those control parameters to be set?", where for example the exact control parameters or a relevant range of the control parameters to be set is displayed on the display 22.

The promptness of the actuator means is adjusted by control unit 15 in a fully automated manner; the driver just has to agree with the adjustment, but the same driver does not have to carry out any further operations, such as manually setting the promptness by means of suitable command members like knobs, levers, and the like. The driver just needs to agree or disagree: if the driver agrees, the latter has to operate the command member 23 accordingly; else, the driver actually has nothing else to do. Control unit 15 completely carries out the adjustment once the driver has agreed.

Additionally or alternatively to the first control mode, the control unit 15 has a second control mode, according to which it is configured to verify if a second specific condition is satisfied and to carry out or to carry out and then hold an adjustment of the promptness of the actuator means, according to the optimal control parameters associated to the determined operative parameter, only if the second specific condition is verified to be satisfied.

In other words, control unit 15 modifies the promptness of the actuator means or holds the modified promptness only under a verification that the second specific condition is satisfied.

This time, the second specific condition is the opposite of the first specific condition; indeed the second specific condition is satisfied when a second input signal is not received by control unit 15.

The second input signal is not any input signal, but a specific signal, more precisely the one sent by command member 23. Here, actually, the second signal may be the same of the first signal, but the control mode is different. This is of course non-limitative ; the second signal could have been sent by one of command members 24, 25, 26. In other words, with respect to the first signal, the second signal may be sent by the same command member 23 or by a different one.

Therefore, control unit 15 adjusts the promptness of the actuator means or maintains the carried out adjustment only if the control unit 15 does not receive the second signal, i.e. only if the driver has not operated the command member 23 to send the second input signal, i.e. if the driver has not disagreed with the adjustment.

In particular, according to an example, from the moment in which the information concerning the control parameters to be set is provided to the driver by the reporting device 20, the control unit 15 waits to receive the second signal before actually adjusting the promptness of the actuator means. More in particular, control unit 15 waits for a predetermined period from said moment.

Indeed, also according to the second control mode, control unit 15 is configured to control the reporting device 20, such that the latter provides the driver with the information concerning the optimal control parameters. The way of providing the information may be similar with respect to the first control mode; therefore, no further details are described concerning the provision of the information.

Then, if control unit 15 does not receive the second signal during the predetermined period, i.e. the command member 23 is not operated to send the second signal to the control unit 15, the latter will proceed with the adjustment of the promptness of the actuator means. Hence , according to the second control mode , the driver has the possibility of refusing the adj ustment of the promptness of the actuator means by the control unit 15 . I f the driver does not refuse the adj ustment , more precisely within the predetermined period, control unit 15 automatically adj usts the promptness .

Again, the driver j ust needs to agree or disagree with the adj ustment : i f the driver disagrees , the latter has to operate the command member 23 to send the second signal to control unit 15 ; else , the driver actually has nothing else to do . Control unit 15 will completely carry out the adj ustment once the predetermined period elapses without the second signal being receipt by control unit 15 .

According to a further example pertaining to the second control mode, control unit 15 is configured to :

- carry out the adj ustment of the promptness of the actuator means, according to the control parameters associated to the determined operative parameters, without waiting for an action of the driver;

- control the reporting device 20 to provide the information concerning the control parameters to the driver, and

- undo the carried out adjustment when receiving the second signal .

Indeed, in this case, the control unit 15 verifies if the second condition is satisfied to hold the carried out adjustment; the adjusted promptness according to the optimal control parameters is hold only if the second condition is verified to be satisfied.

Additionally or alternatively to any of the first and the second control mode or to both, control unit 15 has a third control mode, according to which it is configured to adjust the promptness of the actuator means, according to the control parameters associated to the determined operative parameters, without verifying either of the first or the second specific condition .

More precisely, control unit 15 proceeds with the adjustment of the promptness without an explicit or implicit agreement of the driver . Therefore, in the third control mode, the command device 21 becomes not useful . In other words, in the third control mode, the operation of the command device 21 has no effects on the operation of the control unit 15.

In particular, control unit 15 adjusts the promptness directly in response to the association of the optimal control parameters to the determined operative parameter, namely without verifying any further condition .

Preferably, even in the third control mode, control unit 15 is nonetheless configured to control the reporting device 20, such that the latter provides the driver with the information concerning the optimal control parameters .

Advantageously, vehicle 1 further comprises a mode selector 27 ( Figure 2 ) , which is operable by the driver to set one of a plurality of control modes according to which the control unit 15 controls the actuator means .

The control modes comprise at least any two between the first, second, and third control mode .

Preferably, the control modes comprise all between the first, second, and third control mode .

In particular, the mode selector 27 comprises a switch, more in particular in the form of a button switch, which is operable by the driver to switch between the available control modes .

In view of the foregoing, the advantages of the work vehicle 1 according to the invention are apparent .

The adaptation of the way of driving the vehicle 1 is carried out in a very simple, safe, and comfortable manner, involving just the adjustment of few, but very sensitive parameters, such as the control parameters that affect the promptness of the actuator means of vehicle 1 .

The adjustment of the promptness of the actuator means is carried out substantially in an autonomous manner by the control unit 15, without however ignoring the particular choices of the driver .

Indeed, the driver can set the preferred control mode in a very easy manner, based on the activity that the vehicle 1 should carry out and based on the grade of experience and confidence of the driver .

In particular, the driver can select the first control mode when the same driver wants to maintain the control of the operations of vehicle 1 . Otherwise, the second control mode is more suitable when the driver has more confidence in the evaluations of the control unit 15. Then, the third control mode entirely leaves the control of the promptness of the actuator means to the control unit 15.

The communications between control unit 15 and the driver are easy and comfortable thanks to the reporting device 20 and the control device 21 .

Eventually, it is clear that modifications can be made to the described work vehicle 1 , which do not extend beyond the scope of protection defined by the claims .