Warning method for an aerial work platform, including a scissor lift, and associated aerial work platform

Abstract

Alerting method for a lifting platform, in particular a scissor lift, and associated lifting platform. This alerting method for a lifting platform includes a receiving step (101) of geolocation signals from several navigation satellites. Then, in a calculation step (102), a signal-to-noise ratio is calculated for each geolocation signal, satellites whose signal-to-noise ratio exceeds a predetermined minimum threshold being considered qualified satellites. Next, for several qualified satellites, at least one characteristic angle is measured of a position of these satellites relative to the lifting platform, the at least one characteristic angle being chosen from an elevation angle and an azimuth angle associated with the satellite in question.Next, during a determination step (103), it is determined whether the lifting platform is located indoors or outdoors, based on a distribution of each characteristic angle. Figure for the abbreviation: Figure 3.

Description

Title of the invention: Alert method for a lifting platform, in particular a scissor platform, and associated lifting platform

[0001] The present invention relates to an alert method for a lifting platform, in particular a scissor lift, as well as a lifting platform configured to implement such an alert method.

[0002] A lifting platform refers to a mobile personnel lifting platform. Several types of lifting platforms are known, including articulated platforms, mast platforms, telescopic platforms, scissor platforms, etc. A lifting platform - also simply called a "platform" - comprises a chassis, which is mounted on wheels to allow the platform to move on the ground, a basket, and a lifting device, which is interposed between the basket and the chassis so as to adjust a height of the basket relative to the chassis. The lifting device generally comprises at least one actuator, for example a hydraulic cylinder, which is arranged so as to deploy or retract the lifting device, raising or lowering the basket to the desired working height.The basket, which generally includes a platform surrounded by a guardrail, is designed to accommodate one or more people and possibly also loads such as tools or other equipment, materials such as paint, cement, etc.

[0003] In the particular case of a scissor lift, the lifting device comprises bars, which are articulated in their center in the manner of scissors, several of these scissor mechanisms being mounted one above the other by their ends, which are pivotally connected, so that the assembly formed by the articulated bars can fold and deploy in height. The actuator is arranged between the articulated bars to deploy or fold them. To allow the basket to be lifted, the ends of the upper bars are connected to pads intended to slide in rails provided under the platform of the basket, while the ends of the lower bars are connected to pads intended to slide in rails provided on the chassis.

[0004] Depending on the case, the same lifting platform is required to operate either indoors, i.e. in a sheltered space, for example a warehouse, or outdoors. In the latter case, there is always a risk for the platform to be subjected to wind, for example a gust of wind, even in the absence of a specific weather forecast. It is understood that when the lifting platform is in the deployed configuration, the lifting platform offers significant wind resistance, to the point that in the event of strong wind, the platform risks overturning. Among the various types of lifting platform, the platforms Scissor lifts have, due to the geometry of the lifting device, a significantly greater wind resistance compared to other types of lifting platform. The present invention is thus particularly advantageous when implemented with a scissor lift.

[0005] When the lifting platform is operating indoors, the risk of wind is not completely zero - for example, one can imagine a gust of wind blowing through the open door of a warehouse - but it remains much lower than the risk of wind outdoors. The risk of wind is thus linked to the situation of the lifting platform, depending on whether the lifting platform is indoors or outdoors. It is therefore necessary to remind the operator, present in the basket, of the situation - indoors or outdoors - of the lifting platform and / or of changes in situation, so that the operator becomes aware of the potential wind risk and, if necessary, adapts the way in which the lifting platform is operated accordingly.

[0006] For example, it is known to identify a position of the lifting platform using a satellite geopositioning system - also called GNSS, acronym for Geolocation and Navigation by Satellite System -, then to identify, on a map, whether the lifting platform is inside a building or outside, the risk of being subjected to the wind being generally higher outside. This approach remains, however, limited to circulation in areas that have been previously mapped. In addition, such a method is limited by the precision of the GNSS system.

[0007] US 2015 / 097731-A1 describes, for example, counting the visible satellites and evaluating a ratio between the number of visible satellites divided by a number of satellites theoretically visible at the given time and place, so as to evaluate whether the aerial work platform is located indoors or outdoors. Such a method, however, lacks reliability, for example when the aerial work platform is located in a hangar near an open hangar door, as several satellites may be visible through the door.

[0008] It is these problems that the invention more particularly intends to remedy, by proposing an alert method which is reliable and easy to implement, and in an autonomous manner.

[0009] To this end, the invention relates to an alert method for a lifting platform, the alert method comprising: - a reception step, during which a geolocation signal associated with each of the satellites is received from several navigation satellites by means of a sensor on the lifting platform, - a calculation step, which is subsequent to the reception step and during which, for each signal received and by means of a computer of the lifting platform: • we calculate a signal / noise ratio of this signal, • the received signals are classified, according to the calculated signal-to-noise ratios, according to several predetermined signal-to-noise ratio levels, the predetermined levels being different from each other and including a predetermined minimum threshold, • for several qualified satellites whose received signal has a signal-to-noise ratio greater than the minimum threshold, at least one characteristic angle of a position of each satellite relative to the lifting nacelle is measured, the at least one characteristic angle being chosen from an elevation angle and an azimuth angle associated with the satellite considered, - a determination step, which is subsequent to the calculation step and during which it is determined whether the lifting platform is located indoors or outdoors, based on a distribution of each characteristic angle.

[0010] Thanks to the invention, the operator present in the basket receives an alert when the lifting platform is outside. The operator thus alerted then becomes aware of the potential danger of wind and then adapts, if necessary with regard to the environment in which the lifting platform is moving, a ground travel speed and / or a height of the basket, which makes it possible to reduce the risk of accident. The alert method is notably based on measurements from sensors embedded in the lifting platform and on calculations carried out from these measurements, the alert method being able to be implemented without prior mapping, in other words autonomously. The sorting of satellite signals according to their signal / noise ratio and the evaluation of their spatial distribution around the lifting platform makes it possible to achieve a reliable identification rate of the location, indoors or outdoors, of the lifting platform.

[0011] According to advantageous but not mandatory aspects of the invention, such a control method may incorporate one or more of the following features taken in isolation or in any technically admissible combination: - The several predetermined signal-to-noise ratio levels include at least three predetermined levels, preferably at least five predetermined levels, more preferably at least seven predetermined levels. - The at least one characteristic angle includes the elevation angle, while in the calculation step, the number of qualified satellites whose elevation angle is greater than a predetermined elevation threshold is counted, and the number of qualified satellites whose elevation angle is less than the elevation threshold, and in the determination step, it is determined whether the aerial platform is indoors or outdoors based on the number of its qualified tellites whose elevation angle is above or below the elevation threshold. During the determination step, the lifting platform is considered to be indoors if, for each qualified satellite, the measured elevation angles are less than the elevation threshold. The elevation threshold is between 20° and 70°, preferably between 30° and 60°. The at least one characteristic angle includes the azimuth angle, while in the calculation step the azimuth angle of several qualified satellites is measured, and in the determination step it is determined whether the lifting platform is indoors or outdoors taking into account a distribution of the azimuth angle of the qualified satellites. During the determination step, the lifting platform is considered to be indoors if the qualified satellites are all located, relative to the lifting platform, in the same azimuthal sector having an opening angle of less than 170°, preferably less than 120°, and more preferably less than 90°. The alert method comprises an alert step, which is subsequent to the determination step and during which an alert signal is emitted to an operator present in a basket of the lifting platform, by means of an alert device of the lifting platform, depending on the result of the determination step. During the alert step, an alert signal is issued if the result of the determination step is that the lifting platform is located outdoors. The receiving, calculating and determining steps are repeated several times in succession, while during the alerting step, an alert is issued to the operator if, for two successive determination steps, the result of the first determination step is that the lifting platform is located indoors, while the result of the second determination step is that the lifting platform is located outdoors. During the determination step, it is determined whether the lifting platform is located indoors or outdoors using an expert system. The expert system is based: either on an artificial intelligence algorithm based on a decision tree, or on an artificial neural network, preferably with two layers of neurons.

[0012] According to another aspect, the invention also relates to a lifting platform, in particular a scissor platform, in which: - the lifting platform comprises: • a sensor configured to receive geolocation signals from several geolocation satellites, and • a calculator, configured to interpret the geolocation signals received and to make calculations with the geolocation signals, • alert means, configured to emit an alert signal to the attention of an operator present in the basket of the lifting platform, - the lifting platform is configured to implement the alert method as defined previously.

[0013] Advantageously, the lifting platform also comprises an acknowledgment device, which is configured so that the operator indicates, by actuating the acknowledgment device, that he has taken into account the alert signal transmitted during the alert step.

[0014] The invention will be better understood, and other advantages thereof will appear more clearly in the light of the following description of several embodiments of a method for alerting a lifting platform and of a lifting platform, in accordance with its principle, given solely by way of example and with reference to the appended drawings, in which:

[0015] - [Fig.l] [Fig.l] is a perspective view of a lifting platform conforming to a first embodiment of the invention;

[0016] - [Fig.2] [Fig.2] is a perspective view of the lifting platform of [Fig.l], the lifting platform being represented surrounded by several geolocation satellites, and

[0017] - [Fig.3] [Fig.3] is an example of a block diagram illustrating a method alert implemented by the lifting platform in [Fig.l].

[0018] A lifting platform is shown in [Fig.l]. In the example illustrated, the lifting platform is a scissor lift 10. In a variant not shown, the lifting platform is of another type, for example a telescopic platform, an articulated platform, etc., the principles of the invention described with reference to the scissor lift 10 being transposable to other types of lifting platform.

[0019] The scissor lift 10 comprises a chassis 12 capable of resting and moving on a ground 13 by connecting members, generally wheels 14. The wheels 14 define a forward direction, which is a preferred direction of movement of the chassis 12 and, by extension, of the scissor lift 10.

[0020] The scissor lift 10 comprises a first sensor 12A, which is configured to receive geolocation signals from geolocation satellites. Geolocation signals are radio waves, this aspect is not detailed further.

[0021] The first sensor 12A is here schematically represented by an antenna, which is fixed on the chassis 12. Three geolocation satellites, including a first satellite S1, a second satellite S2 and a third satellite S3, are here represented in [Fig. 2], around the lifting platform 10. The satellites S1 to S3, generically called “satellites S”, are not part of the invention but serve to explain the context and operation thereof. The satellites S are for example part of the same fleet of geolocation satellites, generically called GNSS, an acronym for Global Navigation Satellite System, and translated into French as “Geolocation and Navigation by a Satellite System”. Alternatively, the satellites S belong to different GNSS fleets. A known example of a GNSS satellite fleet is the GPS satellite fleet, an acronym for Global Positioning System.Other non-limiting examples of GNSS satellite fleets are the Galileo or Glonass fleets.

[0022] The number of satellites S shown in [Fig.2] is not limiting. In principle, four visible GPS satellites are necessary to determine a position on the surface of the Earth, while, generally, seven GPS satellites are simultaneously visible at any point on the surface of the Earth. By "satellite visible from a point on the surface of the Earth" is meant that no obstacle, natural or artificial, is interposed between the satellite and the point considered and does not hinder the straight-line propagation of the geolocation signals.

[0023] The lifting platform 10 advantageously comprises a computer 12B, which is configured to interpret the signals received by means of the first sensor 12A and to perform calculations on the basis of these signals. The computer 12B is here represented schematically by a box mounted on the chassis 12.

[0024] The computer 12B is capable of implementing an alert method for the lifting platform 10, the alert method being described later.

[0025] The calculator 12B is an electronic circuit designed to manipulate and / or transform data represented by electronic or physical quantities in registers of the calculator and / or memories into other similar data corresponding to physical data in the memories of registers or other types of display devices, transmission devices or storage devices.

[0026] As specific examples, the calculator 12B is produced in the form of a programmable logic component, such as an FPGA - from the English Field Programmable Gate Array -, or an integrated circuit, such as an ASIC - from the English Application Specific Integrated Circuit

[0027] Alternatively, when the alert method is implemented in the form of one or more software programs, i.e. in the form of a computer program, also called a computer program product, the computer program product is furthermore capable of being recorded on a medium, not shown, that is readable by a computer. The computer-readable medium is, for example, a medium capable of storing electronic instructions and of being coupled to a bus of a computer system. For example, the readable medium is an optical disk, a magneto-optical disk, a ROM memory, a RAM memory, any type of non-volatile memory - for example a so-called FLASH or NVRAM memory - or a magnetic card. A computer program comprising software instructions is then stored on the readable medium.

[0028] The nacelle 10 also comprises a basket 16, and a device 18 for lifting the basket 16. In the example illustrated, the basket 16 comprises a platform 17A, a guardrail 17B, and a controller 17C. In the context of normal use of the aerial work platform 10, an operator stands on the platform 17A and controls the aerial work platform 10 by means of the controller 17C. The controller 17C is configured to transmit information to the operator, and to receive control commands from this operator. According to non-limiting examples, the controller 17C comprises a human-machine interface intended for the operator. For example, the controller 17C comprises buttons and / or control levers, one or more indicator lights or lights, a display screen, possibly a touch screen, one or more audible warning devices.

[0029] In particular, the lifting platform 10 comprises warning means 17D, which are configured to emit a warning signal, luminous and / or audible, to the attention of the operator. In the illustrated example, the warning means 17D are represented by a light indicator, which is integrated into the controller 17C. Preferably, the warning means 17D comprise at least one light-emitting diode, also called DEL in French or LED in English.

[0030] The lifting platform 10 advantageously comprises an acknowledgment device 17E, preferably a two-position monostable switch. The acknowledgment device 17E is here a push button, represented by a cylinder located on the controller 17C. The acknowledgment device is preferably located in the vicinity of the alert means 17D. The acknowledgment device 17E is used, for example, for the operator to confirm that he has received and taken into account the alert signal transmitted by the alert means 17D. The operator, alerted by the alert means 17D, actuates the acknowledgment device 17E if the operator deems it necessary.

[0031] The lifting device 18 comprises a set of articulated bars 20 supporting the basket 16, such that the elevation of the basket 16 relative to the frame 12 is variable and controlled by the set of bars 20. The lifting device 18 comprises also an actuator 22, here a hydraulic cylinder, which actuates the bars 20 to control a height H of the basket 16 relative to the chassis 12, and by extension relative to the ground 13 on which the scissor lift 10 moves. The actuator 22 is for example controlled using the controller 17C, by an operator located on the platform 17A.

[0032] With reference to [Fig. 2], the lifting platform 10 is shown on the ground 13, which delimits a half-space above the lifting platform 10. Schematically, the ground 13 is considered flat and horizontal. The satellites 91 to 93 move relative to the lifting platform 10,

[0033] Considering a reference frame in polar coordinates centered on the nacelle, a position of each satellite relative to the lifting nacelle 10 can be defined by means of three parameters, which are an elevation angle a, an azimuth angle 0, and a distance D. For each satellite, the elevation angle a is the angle formed between the ground 13 and a straight line going from the lifting nacelle 10 towards the satellite considered. The azimuth angle 0 is an angle, measured in projection on the ground 13, between a direction of the satellite S considered and a reference direction.

[0034] Preferably, the reference direction is an absolute direction, i.e. independent of the position of the lifting platform 10 on the ground 13, for example North, as illustrated in [Fig. 2]. In this case, the azimuth angle 0 is an absolute angle, independent of the position of the lifting platform on the ground 13.

[0035] Alternatively, the reference direction is a relative direction, for example defined relative to the lifting platform 10, in particular the forward direction of the lifting platform. In this case, the azimuth angle 0 is a relative angle, which depends on the position of the lifting platform 10 on the ground 13.

[0036] For each satellite S1 to S3, the elevation angle a, the azimuth angle 0 and the distance D associated with this satellite form coordinates {a; 0; D] of this satellite in the reference frame centered on the lifting nacelle. The position of the first satellite S1 is thus identified by the coordinates {a1; 01; D1], the position of the second satellite S2 is identified by the coordinates {a2; 02; D2], and the position of the third satellite S3 is identified by the coordinates {a3; 03; D3}.

[0037] When a geolocation signal, transmitted by one of the satellites S, is received by the first sensor 12A, this geolocation signal is characterized by a signal-to-noise ratio, or SNR - acronym for Signal-to-Noise Ratio in English -. The signal-to-noise ratio depends on the quality of the transmission between the satellite S and the lifting platform 10, in particular depends on the distance D. The lifting platform 10 is thus configured to calculate the signal-to-noise ratio of each geolocation signal received, for example by means of the calculator 12B.

[0038] For each of the satellites SI to S3, each geolocation signal transmitted by this satellite also contains information relating to the elevation angle a and the azimuth angle 0 of this satellite. The lifting nacelle 10 is thus configured to calculate the elevation angle a and the azimuth angle 0 associated with each geolocation signal received, for example by means of the calculator 12B.

[0039] Thus, each satellite S visible from the lifting nacelle 10 is characterized by a signal-to-noise ratio SNR, by an elevation angle a and by an azimuth angle 0.

[0040] With reference to [Fig. 3], the invention thus relates to an alert method for the lifting platform 10. The alert method comprises a reception step 101, during which a geolocation signal associated with each of the satellites is received from several navigation satellites, here the satellites S1a S3, by means of the sensor 12A of the lifting platform 10.

[0041] The alert method also comprises a calculation step 102, which is subsequent to the reception step 101 and during which, for each geolocation signal received and by means of a calculator 12B of the lifting platform 10: - we calculate a signal / noise ratio SNR of this geolocation signal, - we classify the received geolocation signals, based on the reports calculated signal / noise ratio SNR, according to several predetermined levels of signal-to-noise ratio, the predetermined levels being different from each other and including a predetermined minimum threshold. A "qualified satellite" is a satellite whose signal-to-noise ratio is higher than the minimum threshold. - for several qualified satellites, at least one characteristic angle of a position of each satellite relative to the lifting nacelle 10 is measured, the at least one angle being chosen from the elevation angle a and the azimuth angle 0 associated with the qualified satellite considered.

[0042] The alert method also comprises a determination step 103, which is subsequent to the calculation step 102 and during which it is determined whether the lifting platform 10 is located indoors or outdoors, as a function of a distribution of each measured characteristic angle.

[0043] The controller 12B is advantageously configured to implement an expert decision support system, so as to improve the reliability of the results obtained during the determination step 103.

[0044] Schematically, it is understood that if no qualified satellite S is located above the lifting platform 10, then the probabilities that the lifting platform 10 is outside are smaller than if several qualified satellites S are located above the lifting platform 10. Thus, the at least one characteristic angle taken into account during the determination step 103 advantageously includes the elevation angle a: - during calculation step 102, the number of satellites S is counted qualified satellites whose elevation angle a is greater than a predetermined elevation threshold aT, and the number of qualified satellites S whose elevation angle a is less than the elevation threshold aT, - during the determination step 103, it is determined whether the lifting nacelle 10 is located indoors or outdoors depending on the number of qualified satellites S whose elevation angle a is greater than or less than the elevation threshold aT.

[0045] According to examples, during the determination step 103, it is considered that the lifting nacelle 10 is located indoors if, for each qualified satellite S, the measured elevation angles a are less than the elevation threshold aT. Preferably, the elevation threshold aT is between 20° and 70°, more preferably between 30° and 60°.

[0046] Similarly, if several qualified satellites S are regularly distributed around the lifting platform 10, then the probabilities that the lifting platform 10 is outside are higher than if all the qualified satellites are substantially located in the same direction relative to the lifting platform. Thus, the at least one characteristic angle taken into account during the determination step 103 advantageously includes the azimuth angle 0: - during the calculation step 102, the azimuth angle 0 of several qualified satellites S is measured, then - during the determination step 103, it is determined whether the lifting nacelle 10 is located indoors or outdoors, taking into account a distribution of the azimuth angle 0 of the qualified satellites S.

[0047] According to examples, during the determination step 103, it is considered that the lifting nacelle 10 is located indoors if the qualified satellites S are all located, relative to the lifting nacelle 10, in the same azimuthal sector having an opening angle of less than 170°, preferably less than 120°, more preferably less than 90°.

[0048] Preferably, the expert system used in the determination step 103 uses the two characteristic angles, namely the elevation angle α and the azimuth angle θ, to determine whether the lifting platform 10 is located indoors or outdoors.

[0049] Preferably, the expert system is based on an artificial intelligence algorithm based on several decision trees, such an artificial intelligence algorithm being called “AI randomforest” in English. According to a schematic example, the artificial intelligence algorithm uses a first decision tree based on the distribution of the elevation angle α of several qualified satellites S to determine a first time whether the lifting nacelle 10 is located indoors or outdoors, and a second decision tree based on the azimuth angle θ of several qualified satellites S to determine completing a second time whether the lifting platform 10 is indoors or outdoors, the results of the two decision trees then being compared to determine, with increased reliability, whether the lifting platform 10 is indoors or outdoors.

[0050] Alternatively, the expert system is based on an artificial neural network. The neural network comprises an ordered succession of layers of neurons, each of which takes its inputs from the outputs of the previous layer. More precisely, each layer comprises neurons taking their inputs from the outputs of the neurons of the previous layer, or from the input variables for the first layer.

[0051] Each neuron is also associated with an operation, i.e. a type of processing, to be carried out by said neuron within the corresponding processing layer.

[0052] Each layer is connected to the other layers by a plurality of synapses. A synaptic weight is associated with each synapse, and each synapse forms a connection between two neurons. It is often a real number, which takes both positive and negative values. In some cases, the synaptic weight is a complex number.

[0053] Each neuron is capable of performing a weighted sum of the value(s) received from the neurons of the previous layer, each value then being multiplied by the respective synaptic weight of each synapse, or link, between said neuron and the neurons of the previous layer, then applying an activation function, typically a non-linear function, to said weighted sum, and delivering at the output of said neuron, in particular to the neurons of the following layer which are connected to it, the value resulting from the application of the activation function. The activation function makes it possible to introduce non-linearity into the processing carried out by each neuron. Non-limiting examples of activation functions are the sigmoid function, the hyperbolic tangent function, the Heaviside function, etc.

[0054] As an optional addition, each neuron is also capable of applying, in addition, a multiplicative factor, also called bias, to the output of the activation function, and the value delivered at the output of said neuron is then the product of the bias value and the value from the activation function.

[0055] In the application considered, the neural network preferably comprises two layers of neurons. Alternatively, the neural network comprises more than three layers of neurons, such a network being called a “deep network”, or “deep neural networks” in English.

[0056] It is understood that if the signal / noise ratios measured in step 102 are high, then the probabilities that the result of the determination step 103 is reliable are also higher.

[0057] Advantageously, the several predetermined levels of signal-to-noise ratio include at least three predetermined levels, preferably at least five predetermined levels, more preferably at least seven predetermined levels. Thus, during the determination step 103, the qualified satellites S are classified in decreasing order of signal-to-noise ratio, the qualified satellites whose signal-to-noise ratio is higher than the others having more weight in the evaluation of the expert system.

[0058] The alert method advantageously comprises an alert step 104, which is subsequent to the determination step 103 and during which an alert signal is emitted for the attention of an operator present in a basket 16 of the lifting platform 10, by means of an alert device 17D, depending on the result of the determination step 103. Several alert strategies are thus possible.

[0059] According to a first example of an alert strategy, during the alert step 104, an alert signal is emitted only if the result of the determination step 103 is that the lifting platform is located outside. For example, the alert means 17D, here an LED, is lit, continuously or flashing, when the result of the determination step 103 is that the lifting platform 10 is located outside, while the alert means 17D are not activated when the result of the determination step 103 is that the lifting platform 10 is located inside. Activation of the warning means 17D makes the operator, present in the basket 16, aware of the fact that the lifting platform is moving from the inside to the outside, the operator being able to adapt, if necessary, the control of the lifting platform, whether it be the adjustment of the height of the basket 16, the speed of movement on the ground of the lifting platform 10, etc.

[0060] According to a second example of an alert strategy, when the alert means 17D are activated, the operator must then actuate the acknowledgment means 17E to confirm that he has acknowledged the alert signal emitted by the alert means 17D. The fact of having to actuate the acknowledgment means 17E reinforces the operator's awareness of the situation of the lifting platform, indoors or outdoors.

[0061] For example: - the lifting platform 10 is initially located indoors, for example in a hangar. The reception steps 101, calculation 102 and determination 103 are implemented, preferably at regular intervals, for example every 10 seconds. Each time, the result of the determination step 103 being that the lifting platform 10 is located indoors, the alert means 17D are not activated. - The lifting platform 10 then leaves this hangar and is located outside. The reception steps 101, calculation 102 and determination 103 are put implemented, the result of the determination step 103 being that the lifting platform 10 is located outdoors. The alert means 17D are activated so as to draw the operator's attention to the fact that the lifting platform 10 has just moved from an “indoor” environment to an “outdoor” environment. For example, when the alert means include an indicator light, this indicator light is flashing, possibly accompanied by an audible signal. - Then, the operator thus alerted by the alert means 17D, activates the acknowledgment device 17E to confirm that he has received this alert. In the example illustrated, the operator presses the push button. To indicate that the operator's action has been taken into account, the indicator light of the alert means 17D then remains lit continuously, while any audible signal has ended.

[0062] According to another alternative, the alert means include two-color light signals, for example green to signal that the lifting platform 10 is located indoors, and red to signal that the lifting platform 10 is located outdoors.

[0063] According to another alternative, the acknowledgment device comprises a three-position and mono-stable switch. The stable position of the switch is a standby position, while the other two unstable positions of the switch are respectively associated with the indoor or outdoor situations of the lifting platform 10. The stable standby position is preferably located between the two unstable positions.

[0064] When the result of the determination step 103 is that the situation of the lifting platform 10 has changed, for example that the lifting platform 10 has moved from an indoor situation to an outdoor situation (or vice versa), then in the alert step 104 the alert means 17D are activated, for example the indicator light flashes.

[0065] If the operator agrees with the result of the determination step 103, the operator then confirms, by actuating the switch of the acknowledgment device 17E, the situation - inside or outside - of the lifting platform 10, and the indicator light then remains lit continuously. Conversely, if the operator disagrees with the result of the determination step 103, the operator then indicates his disagreement by actuating the switch of the acknowledgment device 17E accordingly, and the indicator light remains flashing.

[0066] According to a variant not shown, the alert means 17D comprise two light-emitting diodes, each being associated with a respective situation, inside or outside, of the lifting platform 10. Preferably, the two light-emitting diodes are arranged on either side around the acknowledgment device 17E.

[0067] More generally, it is understood that multiple arrangements of the alert means 17D and the acknowledgment device 17E are possible, so as to implement the alert step 104 of the alert method of the invention.

[0068] In all cases, the operator indicates, by actuating the acknowledgment device 17E, that he has taken into account the alert signal transmitted by the alert means 17D during the alert step. Depending on the case, the operator confirms or denies, by actuating the acknowledgment device 17E, the result of the determination step 103.

[0069] The embodiments and variants mentioned above can be combined with each other to generate new embodiments of the invention.

Claims

Claims

1. An alerting method for a lifting platform (10), the alerting method comprising: • a reception step (101), during which a geolocation signal associated with each of the satellites (S) is received from several navigation satellites (S) by means of a sensor (12A) of the lifting platform (10), • a calculation step (102), which is subsequent to the reception step (101) and during which, for each signal received and by means of a calculator (12B) of the lifting platform (10): • we calculate a signal / noise ratio of this signal, • the received signals are classified, according to the calculated signal-to-noise ratios, according to several predetermined signal-to-noise ratio levels, the predetermined levels being different from each other and including a predetermined minimum threshold (ST), • for several qualified satellites (S) whose received signal has a signal-to-noise ratio greater than the minimum threshold (ST), at least one characteristic angle of a position of each satellite relative to the lifting nacelle (10) is measured, the at least one characteristic angle being chosen from an elevation angle (a) and an azimuth angle (0) associated with the satellite considered, • a determination step (103), which is subsequent to the calculation step (102) and during which it is determined whether the lifting platform (10) is located indoors or outdoors, based on a distribution of each characteristic angle.

2. A method according to claim 1, wherein: • the several predetermined signal-to-noise ratio levels include at least three predetermined levels, preferably at least five predetermined levels, more preferably at least seven predetermined levels.

3. Method according to any one of claims 1 or 2, wherein: • the at least one characteristic angle includes the elevation angle (a), • during the calculation step (102), the number of qualified satellites (S) whose elevation angle (a) is greater than a predetermined elevation threshold (aT) is counted, and the number of qualified satellites (S) whose elevation angle (a) is less than the elevation threshold, • during the determination step (103), it is determined whether the lifting platform (10) is located indoors or outdoors depending on the number of qualified satellites (S) whose elevation angle (a) is greater or less than the elevation threshold (aT).

4. Method according to claim 3, in which: • during the determination step (103), it is considered that the lifting nacelle (10) is located indoors if, for each qualified satellite, the measured elevation angles (a) are less than the elevation threshold (aT).

5. Method according to any one of claims 3 or 4, in which: • the elevation threshold is between 20° and 70°, preferably between 30° and 60°.

6. Method according to any one of claims 1 to 5, in which: • the at least one characteristic angle includes the azimuth angle (0), • during the calculation step (102), the azimuth angle (0) of several qualified satellites (S) is measured, • during the determination step (103), it is determined whether the lifting nacelle (10) is located indoors or outdoors by taking into account a distribution of the azimuth angle (0) of the sa- qualified tellites (S).

7. Method according to claim 6, in which: • during the determination step (103), it is considered that the lifting nacelle (10) is located indoors if the qualified satellites (S) are all located, relative to the lifting nacelle (10), in the same azimuthal sector having an opening angle of less than 170°, preferably less than 120°, more preferably less than 90°.

8. Method according to any one of claims 1 to 7, in which: • the alert method comprises an alert step (104), which is subsequent to the determination step (103) and during which an alert signal is emitted for the attention of an operator present in a basket of the lifting platform (10), by means of an alert device of the lifting platform (10), depending on the result of the determination step (103).

9. Method according to claim 8, in which • during the alert step (104), an alert signal is emitted if the result of the determination step (103) is that the lifting platform (10) is located outside.

10. Method according to any one of claims 8 or 9, in which: • the steps of reception (101), calculation (102) and determination (103) are repeated several times successively, • during the alert step (104), an alert is issued to the operator if, for two successive determination steps (103), the result of the first determination step (103) is that the lifting platform (10) is located indoors, while the result of the second determination step (103) is that the lifting platform (10) is located outdoors.

11. Method according to any one of claims 1 to 10, in which: • during the determination step (103), it is determined whether the lifting platform (10) is located indoors or outdoors using an expert system.

12. Method according to claim 11, in which: • the expert system is based: • either on an artificial intelligence algorithm based on a decision tree, • or on an artificial neural network, preferably with two layers of neurons.

13. Lifting platform (10), in particular a scissor lift, in which: • the lifting platform (10) comprises: • a sensor (12A) configured to receive geolocation signals from several geolocation satellites (S), and • a computer (12B), configured to interpret the geolocation signals received and to make calculations with the geolocation signals, • alert means (17D), configured to emit an alert signal for the attention of an operator present in the basket of the lifting platform (10), • the lifting platform (10) is configured to implement the alert method according to any one of claims 1 to 12.

14. Lifting platform (10) according to claim 13, in which: • the lifting platform (10) also comprises an acknowledgment device (17E), which is configured so that the operator indicates, by actuating the acknowledgment device (17E), that he has taken into account the alert signal transmitted during the alert step (104). 19