Control of a handling machine

Abstract

[The invention relates to a handling machine (1) comprising: a tilt detector (11) configured to produce a signal relating to a tilting moment applied to the main body about a tilting axis of said handling machine; displacement detectors (18) configured to produce a signal relating to movements of the handling arm relative to the main body; and a control unit (10) configured to: prevent or stop the movement of the handling arm if the signal representing the tilting moment is greater than an effective threshold; assign a value of a descent threshold to said effective threshold in response to a determination of a lowering movement of the handling arm; assign a value of an extension threshold to said effective threshold in response to a determination of an extension movement of the handling arm.

Description

Technical field

[0001] The invention relates to the field of handling machines, in particular the control of a handling arm of such handling machines. Technological background

[0002] A handling machine is known, as described by JP3252006, comprising a machine body and a handling arm mounted to move relative to the machine body. This machine is subjected, on the one hand, to gravitational forces due to the load carried by the handling arm and to the weight of the machine and, on the other hand, to inertial forces induced by the movements of the handling arm. These forces generate a tilting moment applied to the machine body which can cause the machine to become unbalanced or even tilt when they exceed a certain threshold. This machine comprises a control means for limiting the movements of the handling arm in order to prevent such tilting of the machine. In particular, the control means decelerates and then stops the handling arm when approaching a position of the handling arm where the tilting moment is greater than a given threshold.This threshold varies depending on an angle of inclination of the handling arm relative to the ground and an approach rate at an authorized time.

[0003] The threshold used in this machine does not distinguish between the case where the increase in the tipping moment results from a lowering of the handling arm and the case where it results from an extension or lengthening of the handling arm. However, the inertial forces implemented in the two cases are very different.

[0004] Document EP2616382A1 describes a handling machine according to the preamble of claim 1. Summary

[0005] One idea behind this invention is to provide a handling machine that allows for a larger working space of the handling arm without risking the machine tipping over. To this end, another idea behind this invention is to provide a handling machine in which the nature of the movement of the handling arm is taken into account in determining the threshold that causes the movement to be cut off.

[0006] The invention proposes a handling machine comprising: a main body, a telescopic handling arm mounted on said main body and rotatable about a horizontal rotation axis, and deployable and retractable in a longitudinal direction of said handling arm, actuators configured to raise and lower and deploy and retract said handling arm; a tilt detector configured to produce a signal relating to a tilting moment applied to the main body about a tilting axis of said handling machine; movement detectors or movement request detectors configured to produce a signal relating to movements or movement requests of the handling arm relative to the main body;and a control unit configured to receive the signals from the tilt detector and the movement detectors or the movement request detectors and to: slow down, prevent or stop the movement of the handling arm if the signal representative of the tilting moment is greater than an effective threshold; assign a value of a lowering threshold to said effective threshold in response to a determination of a movement or a request for lowering movement of the handling arm; assign a value of an extension threshold to said effective threshold in response to a determination, explicit or implicit, of an extension movement of the handling arm; and in which the value of the lowering threshold is less than the value of the extension threshold. ;

[0007] In particular, the descent threshold represents a smaller tipping moment than the tipping moment represented by the extension threshold.

[0008] Such a machine is advantageous in that it allows the use of a more restrictive threshold for lowering movements of the handling arm than for extending movements of the handling arm. Indeed, the inertial forces generated by interrupting a lowering movement of the handling arm are greater than those induced by interrupting an extension of the handling arm. Adapting the threshold to the type of movement allows the stability limit of the machine to be approached more closely during an extension of the handling arm than during a lowering movement of the arm. The handling machine is thus more efficient while remaining safe.

[0009] According to another aspect of the invention, there is provided a method for controlling a handling machine comprising a main body and a telescopic handling arm mounted on said main body and movable in rotation around a horizontal axis of rotation, and deployable and retractable in a longitudinal direction of said arm, said method comprising: determining a signal relating to a tilting moment applied to the main body relative to a tilting axis of said machine, determining a signal relating to movements or requests for movement of the handling arm relative to the main body, slowing down, preventing or stopping a movement of the handling arm if the signal representing the tilting moment is greater than an effective threshold, assigning a value of a lowering threshold to said effective threshold in response to a determination of a movement or a request for lowering movement of the handling arm assigning a value of an extension threshold to said effective threshold in response to a determination, explicit or implicit, of an extension movement of the handling arm, and in which the value of the lowering threshold is less than the value of the extension threshold.

[0010] The control process can be executed by a control unit included in the handling machine.

[0011] According to advantageous embodiments, such a machine or such a method may have one or more of the following characteristics.

[0012] The actuators of the handling machine can be implemented in different ways. According to one embodiment, the actuators comprise a lifting actuator, for example of the hydraulic or electric type, connected on the one hand to the handling arm and on the other hand to the main body and is configured to move the handling arm in rotation around the axis of rotation in order to perform upward and downward movements.

[0013] According to one embodiment, the handling arm comprises a plurality of deployable segments and the actuators comprise one or more extension actuators, for example of the hydraulic type, each extension actuator being arranged between two or more segments configured to deploy or retract the handling arm.

[0014] The displacement sensors can be implemented in many ways. According to one embodiment, the displacement sensors comprise an angle sensor configured to measure an angle of inclination of the handling arm relative to a horizontal plane or relative to the main body of the handling machine. The angle sensor can be arranged at the axis of rotation. The angle sensor can be an inclinometer.

[0015] Alternatively, the angle sensor may be a sensor arranged on a moving part coupled to the handling arm. Such a sensor may be configured to determine an actuation stroke of the lifting actuator.

[0016] According to one embodiment, the displacement sensors comprise a length sensor configured to measure an extension amplitude of the handling arm. The length sensor may be arranged on one or more segments of the handling arm and configured to measure a distance between the one or more segments relative to the main body.

[0017] Alternatively, the length sensor may be a sensor arranged on a moving part coupled to the handling arm. Such a sensor may be configured to determine an actuation stroke of the extension actuator(s).

[0018] The motion request detectors can be implemented in different ways. According to one embodiment, the motion request detectors can be implemented by one or more sensors equipping a lever or a control wheel, this or these sensors being able, in a non-limiting manner, to be switches, potentiometers or Hall effect sensors, connected to a control unit equipped with a processor connected to the actuating member of the handling arm configured to manually control the handling arm. In particular, said processor can be configured to determine a signal from said actuating member corresponding to a movement to be performed by said handling machine, for example a movement of lowering, lifting, extending and retracting the handling arm. According to one embodiment, the processor can be integrated into the control unit.

[0019] According to one embodiment, the control unit is configured to assign the value of the descent threshold to the effective threshold in response to a determination of a movement or a request for a movement of lowering and extending, simultaneously, the handling arm.

[0020] This configuration allows the descent threshold, which is more restrictive than the extension threshold, to be applied during a compound movement of rotation and extension of the handling arm. The handling machine is therefore safer.

[0021] According to one embodiment, the control unit is connected to the actuators and is configured to reduce a speed or an acceleration of said actuators, and / or stop a hydraulic or electrical supply of said actuators, when the signal representative of the tilting moment is greater than the effective threshold.

[0022] According to one embodiment, a signaling means is arranged in the handling machine and is configured to display or emit a warning signal if the signal relating to the tipping moment is greater than the effective threshold. The warning signal may be audible and / or visual. The signaling means may be a display arranged in a cabin of the handling machine intended for a user of the handling machine. Alternatively, or in addition, the signaling means may be an alarm arranged in said cabin configured to emit the warning signal.

[0023] In particular, the control unit is configured to control the signaling means to display or emit the warning signal.

[0024] The control unit may be configured to determine a movement of the handling arm in various ways. According to one embodiment, the control unit is configured to detect a decrease in the tilt angle measured by the angle sensor and determine a lowering movement of said handling arm in response to a decrease in the tilt angle.

[0025] According to one embodiment, the control unit is configured to detect an increase in the length of the handling arm and determine an extension movement of said handling arm in response to the increase in the length of the handling arm.

[0026] The descent threshold and the extension threshold can be chosen in different ways, in particular with a view to excluding movements involving too high a quantity of movement, namely a quantity of movement that the machine is not able to absorb or dissipate without risk of creating instability. According to one embodiment, the descent threshold and / or the extension threshold are predetermined, in particular as a function of the geometry of the handling arm and the main body and previously stored in a memory on board the handling machine. In particular, the descent threshold and / or the extension threshold are constant.

[0027] According to the invention, the handling arm is orientable around an axis transverse to the main body, in particular a horizontal axis located at a first end of the handling arm, and the main body is mounted on wheels carried by axles, and the tilt detector comprises an extensometer arranged at an axle opposite a second end of the handling arm, and the signal relating to a tilting moment is a signal relating to a deformation of the axle opposite the second end of the handling arm.

[0028] According to one embodiment, the tilt detector comprises several sensors measuring several physical quantities, in particular relating to a load carried by the handling arm and / or to a position of the handling arm. According to this embodiment, the tilt detector is configured to determine the signal relating to a tilting moment as a function of said physical quantities.

[0029] According to one embodiment, the handling machine comprises a plurality of stabilizing feet configured to be deployed or retracted from the main body, and the descent threshold and / or the extension threshold varies depending on whether or not said stabilizing feet are deployed.

[0030] Such a handling machine may in particular be produced in the form of a telescopic arm truck, forklift, lifting crane, mechanical excavator, bucket loader or other. The handling arm may also be orientable around a vertical axis of the main body.

[0031] According to one embodiment, the method comprises an assignment of the value of the descent threshold in response to a determination of a movement or a request for a movement of lowering and extending, simultaneously, the handling arm.

[0032] According to one embodiment, the method comprises determining the angle of inclination of the handling arm relative to a horizontal plane or the main body of the handling machine and determining a lowering movement when the angle of inclination decreases.

[0033] According to one embodiment, the method comprises determining a length of the handling arm and determining an extension movement as the length of the handling arm increases.

[0034] According to one embodiment, the method comprises a signaling step comprising a display or an emission of a warning signal if the signal relating to the tipping moment is greater than the effective threshold. Brief description of the figures

[0035] The invention will be better understood, and other objects, details, characteristics and advantages thereof will appear more clearly during the following description of several particular embodiments of the invention, given solely for illustrative and non-limiting purposes, with reference to the accompanying drawings. [ fig.1 ] there figure 1 is a schematic representation of a handling machine. fig.2 ] there figure 2 is a representation of a tilt detector that can be implemented by the handling machine of the figure 1 . [ Fig. 3 ] there figure 3 is a schematic representation of a control method that can be implemented by the material handling machine figure 1 . [ Fig. 4 ] there figure 4 is a schematic representation of a method for determining an effective threshold that can be implemented by the handling machine of the figure 1 . Description of the embodiments

[0036] In the figure 1 , a handling machine 1, of the forklift type, is shown. The handling machine 1 comprises a chassis 2 supported on the ground by means of a front axle 3 and a rear axle 4. The handling machine 1 comprises a handling arm 6 of the telescopic type mounted on the chassis 2 and orientable around an axis of rotation 7, horizontal relative to the chassis 2. The handling arm 6 comprises a load carrier 14 articulated to the handling arm 6 by the connection 15 and configured to carry a payload 9.

[0037] The handling arm 6 is movable in rotation by a jack 8 connected to the chassis 2 and to the handling arm 6. The handling arm 6 comprises at least two segments 6 1 and 6 2 deployable using an extension jack, not shown, arranged between the at least two segments 6 1 and 6 2 .

[0038] The handling machine 1 further comprises an actuating member 12 for the handling arm 6 configured to manually control the handling arm 6 making it possible to raise and lower and to deploy and retract the handling arm 6.

[0039] There figure 1 shows the handling arm 6 carrying the payload 9 in a high, retracted position in a solid line and in several lower, extended positions in a broken line. The static tilting moment exerted by the handling arm 6 in the forward direction increases as its position descends towards the horizontal and / or as the length of the handling arm 6 increases.

[0040] The handling machine 1 also comprises displacement detectors 18 configured to produce a signal relating to a position of the handling arm 6, in particular an angle of inclination of the handling arm 6 relative to the chassis 2 and / or an extension length of the handling arm 6.

[0041] The displacement detectors 18 comprise for example a first sensor located at the axis 7 and arranged to measure the angle of inclination of the handling arm 6. The displacement detectors are configured to produce a signal representative of the angle of inclination of the handling arm 6 relative to the chassis 2 as a function of the data from the first sensor. The displacement detectors 18 comprise for example a second sensor located at the extension cylinder and arranged to measure a stroke of said extension cylinder. The displacement detectors 18 are configured to produce a signal representative of the extension length of the handling arm 6 as a function of the data from the second sensor.

[0042] The displacement sensors 18 enable the control unit 10 to determine a lowering movement and / or an extending movement of the handling arm 6. In particular, the control unit 10 determines a lowering movement of the handling arm 6 in response to a decrease in the tilt angle. Similarly, the control unit 10 determines an extending movement of the handling arm 6 in response to an increase in the extension length of the handling arm 6, for example an increase in the stroke of the extension cylinder.

[0043] The control unit 10 determines the nature of the movement of the handling arm 6. For this, several methods are possible. For example, the control unit 10 comprises a processing means configured to determine a signal representative of the rotation speed of the handling arm 6 in the direction of the axis 7. In this embodiment, the control unit 10 determines a lowering movement if the rotation speed is non-zero in the direction of the ground. In particular, the signal relating to the rotation speed can be determined by measuring a hydraulic supply flow rate of the cylinder 8. Alternatively, the signal relating to the rotation speed can be determined as a function of a variation over time of the angle of inclination of the handling arm 6. Furthermore, the processing means is configured to determine a signal representative of the extension speed of the handling arm 6.In this embodiment, for example, the control unit 10 determines an extension movement if the extension speed is non-zero in a direction moving away from the chassis 2. In particular, the signal relating to the extension speed can be determined by measuring a hydraulic supply flow rate of the extension cylinder. Alternatively, the signal relating to the extension speed can be determined as a function of the variation over time in the length of the handling arm 6.

[0044] The handling machine 1 further comprises a tilt detector 11 configured to produce a signal relating to a tilting moment applied to the chassis 2 about a tilting axis, located at the front axle 3. Stabilizing feet 5 can optionally be deployed to lift the front axle 3 in which case the stabilizing feet 5 define the tilting axis.

[0045] In one embodiment, shown in the figure 2 , the tilt sensor 11 is arranged at the rear axle 4.

[0046] In the figure 2, the rear axle 4 of the handling machine 1 comprises two wheel support arms 60 carrying rear wheels 62. Each wheel support arm 60 comprises an extensometer 61 configured to measure a tensile deformation of said wheel support arm 60 in a direction perpendicular to said arm 60. Alternatively, the extensometers 61 are configured to measure a bending deformation of the wheel support arm 60, in particular a length variation between two spaced terminals on the wheel support arm 60. The measurement signals of the extensometers 61 may be employed to form the signal indicative of the tipping moment, for example as an average of the two measurement signals. Alternatively, it is possible to employ a single extensometer 61 to produce the signal indicative of the tipping moment.Preferably, the rear axle 4 is connected in an oscillating manner to the chassis 2 by means of a pivot 66 with a longitudinal axis passing through a central part 65 of the axle.

[0047] The handling machine 1 further comprises a control unit 10 configured to receive the signals from the tilt detector 11 and the displacement detectors 18 and to slow down, prevent or stop the movement of the handling arm 6 if the signal representative of the tilting moment is greater than an effective threshold. For example, the control unit 10 is configured to prevent or stop the movement of the handling arm 6 by reducing or stopping the hydraulic supply flow rate of the cylinder 8 and / or the extension cylinder.

[0048] The control unit 10 is also configured to: assigning a value of a descent threshold to said effective threshold in response to a determination of a lowering movement of the handling arm 6; assigning a value of an extension threshold to said effective threshold in response to a determination of an extension movement of the handling arm 6 combined with an absence of lowering movement.

[0049] The value of the lowering threshold is less than the value of the extension threshold, so that the lowering threshold represents a smaller tipping moment than the tipping moment represented by the extension threshold. In other words, for an approach to the stability limit of the handling machine by lowering the handling arm 6, the movement is stopped further from the stability limit, in terms of tipping moment, than for an approach by extending the handling arm 6 without lowering.

[0050] This adjustment takes into account the fact that the inertial forces implemented when interrupting a lowering movement of the arm have a greater influence on the stability of the machine than the inertial forces implemented when interrupting an extension movement of the arm.

[0051] The handling machine 1 comprises a display 13 connected to the control unit 10 and configured to display a warning signal if the signal relating to the tipping moment is greater than the effective threshold.

[0052] In one embodiment, the handling machine comprises an extension detector 16 of the handling arm 6 configured to determine an extension of the handling arm 6.

[0053] In another embodiment, the extension of the handling arm is not expressly measured and the extension sensor is not required. In this case, the effective threshold can be determined on the basis of the tilt angle of the handling arm without taking into account an extension measurement. Indeed, the increase in the tilting moment of the handling machine without lowering the handling arm can be considered in some cases as an implicit detection that an extension movement of the handling arm is in progress.

[0054] Alternatively, the effective threshold can be set, not as a function of the movement of the arm, but as a function of the movement request of the arm, which the control unit receives from the actuating member 12. In this case, the control unit 10 (or a movement request detector not shown in the figures) connected to the actuating member 12 is configured to determine a movement to be performed by the handling arm 6. In this case, the control unit 10 can be configured to: assigning a value of a descent threshold to said effective threshold in response to a determination of a request for lowering movement of the handling arm 6; assigning a value of an extension threshold to said effective threshold in response to a determination of a request for extension movement of the handling arm 6 combined with an absence of lowering movement.

[0055] In any case, the control unit 10 can be configured to implement a control method 200 of the handling machine 1, as shown in the figure 3 .

[0056] The control method 200 serves to slow down, prevent or stop the movement of the handling arm 6 in order to avoid tipping of the handling machine 1.

[0057] Method 200 comprises: a step 201 of determining a signal relating to a tilting moment experienced by the chassis 2, for example by determining an elongation of the rear axle 3, a step 202 of comparing the signal relating to the tilting moment with an effective threshold, a step 203 of slowing down, stopping or preventing the movement of the handling arm 6 when the signal relating to the tilting moment is greater than the effective threshold.

[0058] In one embodiment, the control unit 10 is configured to determine the effective threshold by implementing the method 100 shown in FIG. figure 4 .

[0059] Method 100 comprises: a step 102 of determining a signal relating to the angle of inclination of the handling arm 6 relative to the ground or relative to the chassis of the machine or relative to a horizontal reference, and of determining a signal relating to the extension length of the handling arm 6 a step 103 of assigning a value of a descent threshold to the effective threshold in response to a determination of a decrease in the angle of inclination of the handling arm 6, a step 104 of assigning a value of an extension threshold to the effective threshold in response to a determination of an increase in the length of the handling arm 6.

[0060] Alternatively, step 102 may constitute a step of determining a movement request relating to a lowering or raising of the handling arm 6. The movement request may be determined by determining a particular actuation of the actuating member, for example orientation of the actuating member by a user in a predetermined direction. In this case, step 103 of assigning the lowering threshold to the effective threshold is performed in response to the determination of a request to lower the handling arm and step 104 of assigning the extension threshold to the effective threshold is performed in response to the determination of a request to extend the handling arm 6.

[0061] The descent and extension thresholds are chosen so that the tipping moment represented by the descent threshold is smaller than the tipping moment represented by the extension threshold.

[0062] According to one embodiment, the descent threshold and / or the extension threshold are predetermined and stored in a table or a database. In particular, the descent threshold and / or the extension threshold may be constant or variable.

[0063] According to one embodiment, the descent threshold and the extension threshold are preferably variable depending on whether or not the stabilizing feet 5 are deployed.

[0064] Some elements shown, including the control unit, can be implemented in different forms, in a unitary or distributed manner, using hardware and / or software components. Usable hardware components are specific integrated circuits (ASICs), programmable logic arrays (FPGAs) or microprocessors. Software components can be written in different programming languages, for example C, C++, Java or VHDL. This list is not exhaustive.

[0065] Although the invention has been described in connection with several particular embodiments, it is obvious that it is in no way limited thereto and that it includes all technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

[0066] The use of the verb "comprise", "comprise" or "include" and its conjugated forms does not exclude the presence of other elements or other steps than those set out in a claim.

[0067] In the claims, any reference sign in parentheses cannot be interpreted as a limitation of the claim.

Claims

1. A handling machine (1) comprising: a main body (2), a telescoping handling arm (6) mounted on said main body and rotatable about a horizontal axis of rotation (7), and deployable and retractable along a longitudinal direction of said handling arm, wherein the handling arm (6) is able to be oriented about an axis transverse to the main body located at a first end of the handling arm (6) and the main body is mounted on wheels carried by axles, actuators (8) configured to raise and lower and deploy and retract said handling arm; a tilt detector (11) configured to produce a signal relative to a tilting moment applied to the main body about a tilting axis of said handling machine; movement detectors (18) or movement request detectors configured to produce a signal relative to movements or movement requests of the handling arm relative to the main body; and a control unit (10) configured to receive the signals from the tilt detector and from the movement detectors or movement request detectors and to: slow, prevent or stop (203) the movement of the handling arm if the signal representative of the tilting moment is greater than an effective threshold; assign (103) a value of a lowering threshold to said effective threshold in response to a determination of a movement or of a movement request to lower the handling arm; assign (104) a value of an extension threshold to said effective threshold in response to an explicit or implicit determination of a movement or of a movement request for extension of the handling arm; and wherein the value of the lowering threshold is less than the value of the extension threshold, characterized in that the tilt detector comprises an extensometer arranged at an axle opposite a second end of the handling arm (6), and wherein the signal relative to a tilting moment is a signal relative to a deformation of the axle opposite the second end of the handling arm (6).

2. The machine according to claim 1, wherein the control unit (10) is configured to assign the value of the lowering threshold to the effective threshold in response to a determination of a simultaneous lowering and extension movement or movement request of the handling arm.

3. The machine according to claim 1 or 2, wherein the lowering threshold and / or the extension threshold is predetermined.

4. The machine according to any one of claims 1 to 3, wherein the movement detectors (18) comprise an angle sensor configured to measure an angle of inclination of the handling arm (6) relative to a horizontal plane or relative to the main body (2) of the handling machine.

5. The machine according to claim 4, wherein the control unit (10) is configured to detect a decrease in the angle of inclination measured by the angle sensor and to determine a lowering movement of said handling arm in response to the decrease in the angle of inclination.

6. The machine according to any one of claims 1 to 5, wherein the movement detectors (18) comprise a length sensor configured to measure an extension amplitude of the handling arm.

7. The machine according to claim 6, wherein the control unit (10) is configured to detect an increase in the length of the handling arm and to determine an extension movement of said handling arm in response to the increase in the length of the handling arm.

8. A method for controlling a handling machine (1) comprising a main body and a telescoping handling arm (6) mounted on said main body (2) and rotatable about a horizontal axis of rotation, and deployable and retractable along a longitudinal direction of said arm, wherein the handling arm (6) is able to be oriented about an axis transverse to the main body located at a first end of the handling arm (6) and the main body is mounted on wheels carried by axles, said method comprising: determining (201) a signal relative to a tilting moment applied to the main body relative to a tilting axis of said machine with a tilt detector, determining (102) a signal relative to movements or movement requests of the handling arm relative to the main body, slowing, preventing or stopping (203) a movement of the handling arm if the signal representative of the tilting moment is greater than an effective threshold, assigning (103) a value of a lowering threshold to said effective threshold in response to a determination of a lowering movement or movement request of the handling arm, assigning (104) a value of an extension threshold to said effective threshold in response to an explicit or implicit determination of an extension movement of the handling arm, and wherein the value of the lowering threshold is less than the value of the extension threshold, characterized in that the tilt detector comprises an extensometer arranged at an axle opposite a second end of the handling arm (6), and wherein the signal relative to a tilting moment is a signal relative to a deformation of the axle opposite the second end of the handling arm (6).

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