Field of the invention
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The present invention relates to a method of supporting the execution of a mission of an agricultural or work vehicle and a control unit implementing the method.
State of the art
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Agricultural or work vehicles are equipped with at least one work tool, such as an arm or a lift and a transmission that has the purpose of allowing the vehicle to be moved.
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The transmission can be driven by a prime mover, generally internal combustion, although in recent years vehicles have been developed in which the prime mover is defined by an electric motor.
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As regards the movement of working parts, such as arms, lifts, blades, etc., they are driven by double-action hydraulic actuators.
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A directional valve is arranged to connect one of the opposing chambers of a hydraulic actuator to a source of pressurized hydraulic oil and at the same time the other chamber to a hydraulic oil collection tank, generally at low pressure, i.e. at ambient pressure.
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The source of pressurized hydraulic oil is generally a hydraulic pump driven in rotation by the prime mover or by a dedicated electric motor.
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It is known that the same vehicle can be involved in different missions. Some missions involve the cyclical execution of a sequence of vehicle movements. Furthermore, in the same mission, similar movements, such as the vehicle's advancement, may require two different execution speeds. In fact, while a loader loads material with the bucket in the dig position, the forward movement of the vehicle requires low speed and high torque. On the contrary, when the vehicle has to move from the loading location to the unloading location, the forward movement of the vehicle requires a relatively higher speed and a lower engine torque.
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The main missions for wheel loaders and excavators are:
- Truck loading: removal of material or soil by throwing it directly into a truck via a bucket;
- Hauling: transporting a load of material various distances across a construction site via a bucket;
- Pick & Place: using the fork or bale clamp to pick up and lift the material and then place it at a destination on the ground or on a shelf;
- Material accumulation: definition of a pile by means of the bucket, in a storage location for bulk materials, which is part of the bulk material handling process;
- Roading: when the vehicle moves on the road or in any case on relatively long routes for a significant time interval, i.e. more than 10 minutes.
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In relation to the different missions operated by a vehicle, the operator has the possibility to modify various operating parameters of the vehicle. For example, he can increase or decrease the response of the actuators. If the vehicle performs rough operations, then it is possible to set more aggressive response parameters to maximize productivity by reducing the implementation time of the operations. Conversely, when the vehicle performs delicate operations, then it is appropriate to set softer response parameters in order to give the operator full and constant control of the actuation of the arm and possibly also of the vehicle transmission.
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The Pick & place mission is particularly facilitated in those vehicles equipped with an articulated arm that structurally guarantees the parallelism of the forks with respect to the support surface of the vehicle itself during the lifting or lowering of the forks.
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However, most agricultural or work vehicles are equipped with articulated arms in which the segments are independent. In particular, if a second segment is hinged to a first segment and the first segment is hinged to the vehicle chassis, an activation of an actuator serving the first segment has no impact on the angle formed between the first and second segments. Some of these vehicles may be equipped with functions implemented in a processing unit designed to control the actuation valves of the segments that make up the articulated arm to coordinate the relative actuators in order to automatically ensure the parallelism of the forks with the support surface of the vehicle.
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Examples of articulated arms of vehicles that are not structurally designed to ensure parallelism of the forks are shown in figures 1a and 1b.
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The applicant attributes the commercial name "Zbar" to the arm shown in figure 1a and "XT" to the arm shown in figure 1b. There is a further configuration very similar to the Zbar, called "XR". This differs from the Zbar only in that the main arm has a longer connection.
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Vehicles that implement such independent segment kinematics are equipped with processing units implementing a parallel fork movement function.
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Machine learning and deep learning are well-known concepts. The implementation of deep learning in all fields seems to have considerable development.
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The same applicant holds a
European patent application no. 21217267 which describes a technique for conditioning signals to be input to a neural network, in order to recognize a current mission of the work vehicle.
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Unless specifically excluded in the detailed description that follows, the information in this chapter is to be considered an integral part of the detailed description.
Summary of the invention
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The main purpose of the present invention is to facilitate the execution of a mission of an agricultural or work vehicle equipped with an articulated arm.
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The basic idea of the present invention is to monitor the activity carried out by an articulated arm of an agricultural or work vehicle within a continuous and predetermined time interval and when it turns out that the mission coincides with a "pick & place" mission using forks then the method comprises a step of suggesting to the user or automatically activating the function of parallel movement of the forks.
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According to a preferred aspect of the invention, after or simultaneously with the activation of the parallel movement function the control of the articulated arm is automatically set to "Smooth".
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These and other purposes are achieved by means of the attached claims, which describe preferred embodiments of the invention, forming an integral part of the present description.
Brief description of the figures
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The invention will be fully clear from the following detailed description, provided as a mere example and not limiting, to be read with reference to the attached drawings, in which:
- figure 1 shows a work vehicle with its arm in any of the possible configurations it can assume,
- figures 1a and 1b show examples of articulated arms to which the present invention is addressed;
- figures 2 - 4 show examples of human/machine interfaces. In particular, figure 2 shows a keypad, figure 3 an instrument panel and figure 4 a joystick;
- figure 5 shows an example of a flow diagram representing the method which is the object of the present invention.
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The same reference numbers and letters in the figures designate equal or functionally equivalent parts.
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According to the present invention, the term "second element" does not imply the presence of a "first element", first, second, etc. They are used only to improve the clarity of the description and should not be interpreted in a limitative manner.
Detailed description
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Figure 1 illustrates a construction vehicle such as a wheel loader VHE equipped with an articulated arm A including a first element A_1, substantially elongated, hinged to the vehicle frame F and a second element A_2, such as a bucket or a fork, hinged to the first element. More specifically, a first end of the first element is connected to the vehicle frame F, while a second end, opposite to the first one, supports the second element.
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It is clear that the first element can assume multiple angular positions with respect to the frame F.
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The hydraulic actuator A1 is arranged to control the angular position of the first element A_1 with respect to the vehicle frame.
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The hydraulic actuator A2 is arranged to control the angular position of the second element A_2 with respect to the first element A_1.
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The hydraulic actuators A1, A2 are of the double-action type, with two opposing chambers separated by a mobile septum integral with the stem of the respective actuator.
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The operation of the first actuator, without any correction made on the second actuator, causes the forks to rotate with respect to the hinge point of the first element with the frame. An electro-hydraulic valve, not shown, controls the connection of one of said opposing chambers alternately with a source of hydraulic oil or with a hydraulic oil tank accumulator. Generally, when a chamber is connected with the source of hydraulic oil, the opposite chamber is connected with the hydraulic oil tank.
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An electro-hydraulic valve, generally open-center, thus takes care of the control of a respective actuator.
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The valve activation is instead controlled by a human/machine interface device, such as a joystick JK, shown in figure 4. The joystick may have several buttons, whose functionality may be fixed or programmable based on settings given by the operator using the button panel 21 of figure 2 or using the instrument panel 20 shown in figure 3.
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The joystick comprises at least one button 23, 24, 25. Often it also comprises a wheel 26 that allows adjustments to be made to some operating settings.
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The processing unit VCU supervises the operation of the electro-hydraulic valves activated in response to an action on the joystick.
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When the parallel fork movement function is active, the processing unit VCU controls the activation of the second actuator A2 as well as the actuator A1, when the operator commands the lifting/lowering of the arm by controlling the first actuator using the joystick.
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In other words, the operator acts on the joystick to control only the first actuator, however, the processing unit acts on the solenoid valves so as to operate not only the actuation of the first actuator but also of the second actuator, ensuring the parallelism of the forks with respect to the support surface of the vehicle.
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According to the present invention, a first software module, implemented in the processing unit VCU, is responsible for monitoring the configurations assumed by the arm and the operation of the propulsion system and for determining the current mission of the vehicle.
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More preferably, a processing unit VCU is configured to implement the first and further a second software module and to control the instrument panel 20 in particular to reproduce messages through the respective display 22.
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In particular, the processing unit is configured to check whether the current mission is pick&place. If so, the activation status of the parallel movement function of the forks is checked.
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If this is already active, the second software module does not perform any action, vice versa, if it is not active, then the second software module can alternatively activate the fork parallel movement function or suggest its activation via the display in figure 3, via a recorded written or vocal message, or via the lighting of a warning light.
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The operator can set the activation of the fork parallel movement function by means of one of the buttons at his disposal, or he can set the automatic activation of the function by the processing unit VCU. In the latter case, no suggestion is given to the operator via the available human/machine interface devices, but the parallel movement is activated automatically.
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Advantageously, the operator is given the possibility of having the vehicle decide automatically or of maintaining control of the fork parallel movement function, so that the vehicle limits itself, via the instrument panel, to giving suggestions.
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With reference to figure 5, an exemplary flow diagram of the present invention is shown. The dashed blocks are optional:
- Step 1: Observation of frequency and time duration of each operating configuration of the arm and activation of the propulsion system;
- Step 2: determination of the current mission of the vehicle;
- Step 3: verification whether said vehicle mission coincides with a pick&place mission;
- Step 4: suggestion of activation of the function of parallel movement of the forks or activation of the function of parallel movement of the forks; if not, it starts again from the beginning.
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According to a preferred aspect of the invention, the processing unit is configured to determine the current mission based on the observation of the frequency and time of residence of the articulated arm in predetermined configurations and on the observation of the frequency and time of residence of the transmission in a predetermined rotation regime.
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For further details see the applicant's
European patent application No. 21217267 .
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The method may comprise a step of inhibiting any suggestion or action when the function of parallel movement of the forks is already active.
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It is worth highlighting that suggestions can be given to the operator not only by means of texts that appear on the instrument panel or by the flashing of a light associated with a button to enable an automatic function, but also by means of voice messages.
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Similarly, the operator can confirm the enabling of an automatic function vocally.
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Therefore, the processing unit can advantageously be equipped with a voice synthesis module, an acoustic diffuser and/or a microphone to give suggestions to the operator or to receive orders given by the operator.
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According to a preferred aspect of the invention, preliminarily, it is considered as actually a pick&place mission, when the processing unit, implementing the method described in the applicant's
European patent application no. 21217267 , continuously recognizes the pck&place mission for a predetermined time interval. For example, this condition is satisfied when the VCU unit recognizes a pick&place activity for 30 consecutive minutes.
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According to a further preferred aspect of the invention, when the vehicle is equipped with a sensor associated with the articulated arm that allows to detect the type of tool connected to it, then the VCU unit, in addition to detecting a pick&place activity as a mission, verifies that a fork is operationally connected to the articulated arm.
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According to a further preferred aspect of the invention, in response to the activation of the function of parallel movement of the forks, a smooth setting is also set, step 5, in the activation of the actuators A1, A2 and preferably also of the transmission, which is responsible for transferring drive torque to the vehicle wheels or tracks.
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It is worth highlighting that the same processing unit can be installed on board different agricultural or work vehicles.
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This implies that some functions must be enabled on some vehicles and not on others. It is advantageous for the same processing unit to self-configure according to the vehicle on which it is installed.
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For this purpose, according to a preferred variant of the method which is the subject of the present invention, the processing unit can provide for the verification, step 3bis, of the condition that the vehicle is not equipped with an articulated arm constructively designed to ensure parallel movement of the forks with the support surface of the vehicle. On the contrary, vehicles equipped with an articulated arm that constructively guarantees the parallel movement of the forks are generally referred to as intrinsically "parallel lift".
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In other words, the processing unit preferably checks whether the segments of the articulated arm are independently moved, i.e. not intrinsically "parallel lift".
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This information is generally published by an appropriate software module on the vehicle data network. In this case, in fact, it is appropriate to inhibit any message or evaluation regarding the opportunity to activate this function that objectively would not lead to any advantage.
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The activation of the smooth setting, can be operated independently and autonomously from the activation of the fork parallelism function. Furthermore, the smooth setting is independent of the preliminary check that the segments of the articulated arm are independently moved, as this setting can be applied to any vehicle regardless of the structure of the relative articulated arm.
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The present invention may be advantageously implemented in a computer program comprising program code means for executing one or more steps of such method, when such program is executed on a computer. For this reason, the patent will also cover such computer program and computer-readable medium comprising a recorded message, such computer-readable medium comprising program code means for executing one or more steps of such method, when such program is executed on a computer.
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The features disclosed in the background of the prior art are introduced only for a better understanding of the invention and not as a statement of the existence of the prior art. Furthermore, said features define the context of the present invention, so such features will be considered in common with the detailed description.
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Further details of implementation will not be described, as the person skilled in the art is able to carry out the invention starting from the teaching of the above description.