Methods and systems for estimating a load lifted by electric lifting means

Abstract

The present invention relates to a method, system and non-transitory computer-readable storage medium for estimating a load lifted by an electric motor, irrespective of the type of actuation and / or the speed at which the load is lifted, in order to maintain operational safety. The method comprises starting a calibration step comprising: providing a first load of known mass that is lifted to a calibration height; actuating a motor and measuring the current and voltage to obtain the energy consumed; and obtaining lifting efficiency values in order to perform the calibration. The method subsequently comprises starting a working operation comprising: with a second load of unknown mass: actuating the motor; measuring the working current and voltage in order to obtain the working energy consumed; obtaining an estimated potential lifting energy; and determining the estimated mass of the second load based on the estimated potential lifting energy.

Description

[0001] METHODS AND SYSTEMS FOR ESTIMATING THE LOAD LIFTED BY ELECTRIC LIFTING MEANS DESCRIPTIVE MEMORANDUM FIELD OF THE INVENTION

[0002] The present invention relates to the industry of transporting and handling cargo using electrical means. In particular, the present invention relates to a method and system for estimating a load lifted by lifting means powered by an electric motor and / or electric motion generation means, independent of the method of drive and / or the lifting speed of the load, without generating invasive interventions in said lifting means.

[0003] The load estimation method of the present invention can be applied to lifting machines and / or equipment powered by an electric motor and / or an electric motion generation means, where the correct evaluation of the load transported and lifted by said lifting machines and / or equipment is necessary to maintain their stability, allowing knowledge of whether the lifted load is within safe operating ranges, both to avoid damage and / or failures in the lifting machines and / or equipment, and to maintain the safety of the operator of said machines and / or equipment, avoiding possible accidents caused by the incorrect evaluation of the load, such as the overturning of the lifting means, which would have serious consequences for the operator, the lifting equipment, the operating environment and / or the load itself.

[0004] Lifting machines and / or equipment generally lack built-in means of measuring the load, requiring additional sensors such as weight sensors or load cells, which can be exposed and / or damaged during load handling. Consequently, the need arises to estimate the load lifted by these machines and / or lifting equipment without direct intervention from the lifting device or direct measurement of the load. The present invention discloses a method and system for estimating the load lifted by an electrically powered lifting machine and / or lifting equipment by measuring the current and voltage of the electric motor and / or electric motion generation device that drives said machine and / or lifting equipment, independent of the drive mechanism of the electric motor and / or electric motion generation device and independent of the speed at which the load is lifted.

[0005] In the industrial sector, forklifts, hoists, and other lifting equipment play a crucial role in a wide range of activities, moving loads of varying sizes and weights. However, the variability in load weight presents challenges, as it is not always easily measurable. Installing sensors directly on the fork structure is one option, but these sensors can be damaged due to direct contact with the load, affecting their reliability and the equipment warranty. Currently, the market offers several solutions to address this challenge. Firstly, there are designs for integrating and manufacturing generic and custom-made weighing systems. This method and system, designed to manage and administer each forklift with its scale in real time via the internet, offers a versatile and mobile solution.It replaces traditional forks with ones designed with digital cells inside, along with a device for data transmission, allowing digital control and traceability of the weight of the transported load.

[0006] Secondly, we have a forklift weighing system that provides instant, digital readings of the transported load. This system involves replacing the forks with ones equipped with internal weight cells, displaying the transported load on a screen. Finally, a forklift scale offers accurate weighing results even in adverse and challenging conditions. These scales are mounted on the front of the forklift, recording the pallet's weight the moment the forklift picks up the load. The data is then wirelessly transferred to billing and warehouse management systems.

[0007] STATE OF THE ART

[0008] Currently, the industry of transport and handling cargo using electric means presents the problem of: estimating a load lifted by lifting means powered by an electric motor and / or means of generating electric movement, independent of the method of drive and / or the speed of lifting the load, without generating invasive interventions in said lifting means and in the state of the art, various solutions have been found, which partially solve the technical problem raised.

[0009] Within the state of the art of indirect measurements is PCT application number PCT / CL2023 / 050009 which discloses, in general terms, the measurement and / or control of mechanical variables through current, in particular it discloses a method for measuring an impact frequency of a hammer of a drilling machine without the installation of sensors on the hammer which comprises performing, by means of at least one processor.

[0010] Within the state of the art is PCT application number PCT / CL2023 / 050129 which discloses, in general terms, the measurement of current and voltage to obtain other parameters, in particular, this application comprises a method for measuring a hammer impact frequency of a drilling machine, torque magnitude and speed of the electric motor by analyzing the current and voltage that feeds an electric motor of a rotation subsystem of the machine, without sensors on the hammer, by means of a processor.

[0011] Another state-of-the-art document is publication FR2972253A1, which discloses a method for determining the weight of a lifted load. The load is lifted by a lifting mechanism that includes an electric motor, measuring means for capturing an electrical quantity received by the electric motor, and measuring means combined with a computer device. This method involves waiting for the initial lifting time before entering the magnitude of the current and power consumed by the electric motor during a predefined measurement time, thereby determining the weight of the load.

[0012] However, none of the aforementioned patent publications solves the technical problem of estimating a load lifted by lifting means or cantilever load-holding lifting means, powered by an electric motor and / or electric motion generation means, independent of the method of drive and / or the lifting speed of the load, by measuring the current and voltage of the electric motor and / or electric motion generation means, without making invasive interventions in said lifting means.

[0013] SOLUTION TO THE TECHNICAL PROBLEM

[0014] To address the problem, a method and system are presented to estimate a load lifted by lifting means powered by an electric motor, independent of the method of drive and / or the speed of lifting the load, by measuring the current and voltage of the electric motor and / or the means of generating electric motion, without generating invasive interventions in said lifting means.

[0015] SUMMARY DESCRIPTION OF THE INVENTION

[0016] The present method, system, and non-transient computer-readable storage medium for estimating a load lifted by lifting means driven by an electric motor and / or electric motion generation means, independent of the drive method and / or the lifting speed of the load, to maintain operational safety, wherein the method comprises: initiating a calibration stage, wherein the calibration stage comprises: providing a first load of known mass that is lifted to a calibration height; operating lifting means; measuring a current and voltage to obtain an electrical power as a function of time; obtaining energy consumed; and obtaining at least one lifting efficiency value; obtaining the calibration; initiating a work operation, which comprises: providing at least a second load with an unknown mass; operating the lifting means;Measure the current and voltage working to obtain an electrical power working as a function of time; and obtain a working energy consumed; obtain an estimated lifting potential energy (EPL2); and determine an estimated mass (me) of the second load, from the estimated lifting potential energy (EPL2), to maintain operational safety.

[0017] This method estimates the load transported by measuring the power and electrical energy supplied to the motor that drives the hydraulic lifting system's pump. Since the load lifting speed is variable and depends on the operator, this methodology defines a lifting efficiency that helps normalize this variability for a more accurate estimate. The method's independence from lever operation and lifting speed is achieved by measuring the electric motor's current and voltage during the lifting operation. These measurements reflect the lever operation and speed, which affect the motor's electrical energy consumption and, consequently, the lifting efficiency. Therefore, the method can estimate the load mass independently of these difficult-to-control variables.

[0018] The advantages of the present invention include:

[0019] 1 Reduction of the number of sensors directly exposed in the load transport process on the fork.

[0020] 2.- Possibility of using current and voltage sensors that are already present in electric cranes.

[0021] 3.- Increased system reliability, preventing accidents caused by overload.

[0022] 4.- General reduction in implementation and operating costs.

[0023] 5.- Replicable and scalable methodology for any electric forklift.

[0024] 6.- Avoid potential warranty losses, since this system is non-invasive and has a low implementation cost.

[0025] DESCRIPTION OF THE FIGURES

[0026] Figure 1 shows some terminals of the Traction motor.

[0027] Figure 2 shows some terminals of the lift motor.

[0028] Figure 3 shows a power steering motor.

[0029] Figure 4 shows the location of data collection equipment on the Toyota® FBMF-16 Forklift.

[0030] Figure 5 shows a visual representation of test cycles.

[0031] Figure 6 shows the elements used in testing, Figure 6(a) LCB tank, Figure 6(b) low profile scale and Figure 6(c) digital weighing indicator.

[0032] Figure 7 shows the electrical signals (a) Voltage and (b) current.

[0033] Figure 8 shows the electrical power signal for a load of 202.5[kg] on the lifting motor.

[0034] Figure 9 shows the electric power of the lifting motor, Figure 9 (a) at no load and Figure 9 (b) with a load of 202.5 [kg]. Figure 10 shows the energy consumed by the lifting motor in kWs (or kJ), Figure 10 (a) at no load and Figure 10 (b) with a load of 202.5 [kg].

[0035] Figure 11 shows a Boxplot of energy consumption versus load on a Toyota® FBMF-16 forklift lifting motor.

[0036] Figure 12 shows the efficiency versus median electrical power.

[0037] DETAILED DESCRIPTION OF THE INVENTION

[0038] The present invention relates to a method for estimating a load lifted by lifting means driven by an electric motor and / or electric motion generation means, independent of the drive method and / or the lifting speed of the load, in order to maintain operational safety, comprising:

[0039] a) initiate a calibration stage, where the calibration stage comprises:

[0040] i. provide a first load that has a known mass and is to be lifted to a predetermined calibration height during at least two calibration lifting operations;

[0041] i. actuate lifting means by means of at least one electrical motion generation means to lift the first load;

[0042] iii. measure a current as a function of time and a voltage as a function of time of at least one electrical motion generation means during at least two calibration lifting operations of the first load to the calibration height;

[0043] iv. obtain an electrical power as a function of time from at least one means of generating electrical motion during the at least two calibration lifting operations of the first load to the calibration height from the current as a function of time and the voltage as a function of time;

[0044] v. obtain an energy consumed (EEL) by at least one means of generating electrical motion during each of the at least two calibration lifting operations from the electrical power as a function of time; and

[0045] vi. obtain at least two lifting efficiency (EFF) values ​​from the comparison between the energy consumed (EEL) during each of the at least two calibration lifting operations and a lifting potential energy (EPL) associated with the known mass and calibration height; b) obtain, from the at least two lifting efficiency (EFF) values ​​obtained during the at least two calibration lifting operations, a relationship between an estimated lifting efficiency value (EFF2) and a characteristic value of electrical power as a function of time;

[0046] c) start a work operation, which includes:

[0047] i. provide at least a second load with an unknown mass to be lifted to a predefined working height (Irr) during at least one working lifting operation;

[0048] i. actuate the lifting means by means of at least one electrical motion generation means to lift the second load;

[0049] iii. measure a working current as a function of time and a working voltage as a function of time of at least one electrical motion generation means during at least one working lifting operation of the second load to the predefined working height (hy);

[0050] iv. obtaining a time-dependent electrical working power from at least one means of generating electrical motion during at least one working lifting operation of the second load to the predefined working height (IIT) from the time-dependent working current and the time-dependent working voltage; and

[0051] v. obtain an energy of work consumed (EELT) by at least one means of generating electrical motion during each of the at least one work lifting operation from the electrical work power as a function of time;

[0052] d) obtain, from the relationship obtained in step b) and the work energy consumed (EELT) obtained in step c), an estimated potential energy of lift (EPL2); and

[0053] e) determine an estimated mass (m e) of the second load, based on the estimated lifting potential energy (EPL2), to maintain operational safety.

[0054] In a preferred configuration in calibration stage a), from substage i to vi, it is performed iteratively, and where the mass of the first load is modified in a known way for each iteration of calibration stage a); additionally for each iteration of calibration stage a) the mass of the first load is modified with constant mass differentials.

[0055] In another preferred configuration in calibration stage a), from substage i to vi, it is performed iteratively, and where the calibration height is modified in a known way for each iteration of calibration stage a); additionally for each iteration of calibration stage a) the calibration height is modified with constant height differentials.

[0056] In another preferred configuration, the lifting action is performed with at least one lifting means which is an electric motor of at least one phase.

[0057] In another preferred configuration, the method further comprises repeating steps c) ae) iteratively for each new load that is lifted.

[0058] In another preferred configuration, in step a) and in step c) the actuation of the lifting means is carried out through an actuator; additionally in step a) and in step c) the actuation of the lifting means carried out through the actuator is variable or constant.

[0059] In another preferred configuration, in sub-step iv of step a), obtaining the at least two lifting efficiency (EFF) values ​​from the comparison between the energy consumed (EEL) during the at least two calibration lifting operations and a potential lifting energy (EPL) associated with the known mass and calibration height, is done through EFF = EPL / EEL.

[0060] In another preferred configuration, in stage e), the estimated mass (m e ) is obtained through m e = (EPL2) / (g ■ T), where g is the acceleration due to gravity.

[0061] In another preferred configuration, in stage b), the relationship between the estimated lifting efficiency value (EFF2) and the characteristic value of the electrical power as a function of time is obtained by a regression; additionally the regression is linear; or the regression is non-linear, such as: quadratic, exponential, logarithmic, power, polynomial, among others; and furthermore the characteristic value of the electrical power as a function of time corresponds to the median of the electrical power as a function of time.

[0062] In another preferred configuration, current as a function of time and voltage as a function of time are measured by means of measurement, where the means of measurement are measuring equipment selected from: ammeter probes, voltage probes, multimeter, ammeter, voltmeter, oscilloscope, among others.

[0063] In another preferred configuration, the work operation c) further comprises in stage ill: measuring a second working current as a function of time and a second working voltage as a function of time of at least one second means of generating electrical motion during at least one displacement operation of the second load, in order to determine more accurately the estimated mass (m e ) of the second load; optionally, work operation c) further comprises in stage 11: measuring acceleration variations through an IMU, where the IMU is an inertial measurement unit or accelerometer. In another preferred configuration, where work operation e) further comprises triggering an alarm when the transported load exceeds at least 50% of a nominal capacity; optionally, work operation e) further comprises triggering the alarm when the transported load exceeds at least 70% of the nominal capacity.

[0064] The present invention also relates to a system for estimating a load lifted by lifting means driven by an electric motor and / or electric motion generation means, independent of the method of drive and / or the lifting speed of the load, in order to maintain operational safety, comprising:

[0065] a base structure comprising lifting means operatively connected to said base structure and at least one electrical motion generating means rigidly connected to the base structure and further said at least one electrical motion generating means operatively connected to the lifting means for lifting at least one load during at least one calibration or work lifting operation;

[0066] a power source electrically connected to it at least one means of generating electrical motion;

[0067] means for measuring current as a function of time and voltage as a function of time, electrically connected to the means for generating electrical motion;

[0068] one or more processors connected to the time-dependent current and time-dependent voltage measurement means, comprising a display means, at least one human interface, and one or more processors implemented in circuits and communicatively coupled to a memory that are configured to execute the following steps:

[0069] a) initiate a calibration stage, where the calibration stage comprises:

[0070] i. provide a first load that has a known mass and is to be lifted to a predetermined calibration height during at least two calibration lifting operations;

[0071] i. actuate the lifting means by means of at least one electrical motion generation means to lift the first load;

[0072] iii. measuring a current as a function of time and a voltage as a function of time of at least one electrical motion generating means during the at least two calibration lifting operations of the first load to the calibration height; iv. obtaining an electrical power as a function of time of at least one electrical motion generating means during the at least two calibration lifting operations of the first load to the calibration height from the current as a function of time and the voltage as a function of time;

[0073] v. obtain an energy consumed (EEL) by at least one means of generating electrical motion during each of the at least two calibration lifting operations from the electrical power as a function of time; and

[0074] vi. obtain at least two lifting efficiency (EFF) values ​​from the comparison between the energy consumed (EEL) during each of the at least two calibration lifting operations and a lifting potential energy (EPL) associated with the known mass and calibration height;

[0075] b) obtain, from the at least two lifting values ​​obtained during the at least two calibration lifting operations, a relationship between an estimated lifting efficiency value (EFF2) and a characteristic value of electrical power as a function of time;

[0076] c) start a work operation, which includes:

[0077] i. provide at least a second load with an unknown mass to be lifted to a predefined working height (Irr) during at least one working lifting operation;

[0078] i. actuate the lifting means by means of at least one electrical motion generation means to lift the second load;

[0079] iii. measure a working current as a function of time and a working voltage as a function of time of at least one electrical motion generation means during at least one working lifting operation of the second load to the predefined working height (hy);

[0080] iv. obtaining a time-dependent electrical working power from at least one means of generating electrical motion during at least one working lifting operation of the second load to the predefined working height (IIT) from the time-dependent working current and the time-dependent working voltage; and

[0081] v. obtain a work energy consumed (EELT) by the at least one means of generating electrical motion during each of the at least one work lifting operation from the electrical work power as a function of time; d) obtain, from the relationship obtained in step b) and the work energy consumed (EELT) obtained in step c), an estimated lifting potential energy (EPL2); and

[0082] e) determine an estimated mass (m e ) of the second load, based on the estimated lifting potential energy (EPL2), to maintain operational safety.

[0083] In a preferred configuration, the means of measuring current as a function of time and voltage as a function of time are measuring equipment selected from: ammeter probes, voltage probes, multimeter, ammeter, voltmeter, oscilloscope, among others, where the data is transferred wirelessly to the billing and warehouse management systems.

[0084] In another preferred configuration, the at least one lifting means is an electric motor of at least one phase; a direct current (DC) electric motor; or an alternating current (AC) electric motor with star or delta configuration.

[0085] In another preferred configuration, the system also includes an alarm that is selected from an audible, vibrating and / or visible alarm.

[0086] The present invention also relates to a non-transient, computer-readable storage medium that stores instructions which, when executed, cause one or more processors to perform the following steps:

[0087] a) initiate a calibration stage, where the calibration stage comprises:

[0088] i. provide a first load that has a known mass and is to be lifted to a predetermined calibration height during at least two calibration lifting operations;

[0089] i. actuate lifting means by means of at least one electrical motion generation means to lift the first load;

[0090] iii. measure a current as a function of time and a voltage as a function of time of at least one electrical motion generation means during at least two calibration lifting operations of the first load to the calibration height;

[0091] iv. obtain an electrical power as a function of time from at least one means of generating electrical motion during the at least two calibration lifting operations of the first load to the calibration height from the current as a function of time and the voltage as a function of time;

[0092] v. obtain an energy consumed (EEL) by at least one means of generating electrical motion during each of the at least two calibration lifting operations from the electrical power as a function of time; and

[0093] vi. obtain at least two lifting efficiency (EFF) values ​​from the comparison between the energy consumed (EEL) during each of the at least two calibration lifting operations and a lifting potential energy (EPL) associated with the known mass and calibration height;

[0094] b) obtain, from the at least two lifting efficiency values ​​obtained during the at least two calibration lifting operations, a relationship between an estimated lifting efficiency value (EFF2) and a characteristic value of electrical power as a function of time;

[0095] c) start a work operation, which includes:

[0096] i. provide at least a second load with an unknown mass to be lifted to a predefined working height (Irr) during at least one working lifting operation;

[0097] i. actuate the lifting means by means of at least one electrical motion generation means to lift the second load;

[0098] iii. measure a working current as a function of time and a working voltage as a function of time of at least one electrical motion generation means during at least one working lifting operation of the second load to the predefined working height (hy);

[0099] iv. obtaining a time-dependent electrical working power from at least one means of generating electrical motion during at least one working lifting operation of the second load to the predefined working height (IIT) from the time-dependent working current and the time-dependent working voltage; and

[0100] v. obtain an energy of work consumed (EELT) by at least one means of generating electrical motion during each of the at least one work lifting operation from the electrical work power as a function of time;

[0101] d) obtain, from the relationship obtained in step b) and the work energy consumed (EELT) obtained in step c), an estimated potential energy of lift (EPL2); and

[0102] e) determine an estimated mass (m e ) of the second load, based on the estimated lifting potential energy (EPL2), to maintain operational safety. It should be understood that the different options previously described for different technical characteristics of the computer-readable methods, systems, or means that are the subject of the present invention may be combined with each other, or with other options known to a person normally versed in the art, in any manner provided without this limiting the scope of the present application.

[0103] In the context of this request, and without limiting its scope, "at least one" shall be understood to mean one or more of the elements referenced. Therefore, the number of elements referenced does not limit the scope of this request. Furthermore, if more than one element is provided, those elements may or may not be identical, without limiting the scope of this request.

[0104] The grammatical articles "a," "an," "the," and "the," as used herein, are intended to include "at least one," "at least one," "one or more," or "one or more," unless the context indicates or requires otherwise. Therefore, the articles are used herein to refer to one or more of the grammatical objects of the article. By way of example, "a component" means one or more components, and thus more than one component may be contemplated and used in an implementation of the invention. Furthermore, the use of a singular noun includes the plural, and the use of a plural noun includes the singular, unless the context of use requires otherwise.

[0105] The use of terms such as: "includes", "which includes", "including", "has", "which has", "having", "contains", "which contains", "containing", "comprising" or "comprising", even incorporating some grammatical equivalents of these, should generally be understood as open and non-limiting, e.g., not excluding additional unmentioned elements or steps, unless explicitly stated or understood otherwise in the described context.

[0106] In the context of this application, and without limiting its scope, "plurality" shall be understood to mean two or more of the elements referred to herein. Consequently, the number of elements of the plurality referred to does not limit the scope of this application, provided it is greater than or equal to two. Furthermore, these elements of the plurality may or may not be identical to one another without this limiting the scope of this application.

[0107] When the term "approximately" or "around" is used before a quantitative value, these teachings also include the specific quantitative value, unless specifically stated otherwise. As used herein, the term "approximately" or "around" refers to a variation of ±10% of the stated nominal value, unless a range is explicitly stated herein. Unless otherwise stated, if the term "approximately" or "around" is mentioned before the first extreme value of a numerical interval, or a set of numbers, regardless of their mode of representation (e.g., ratios of the type A:B or A / B, where A and B are whole numbers or decimals, among other numerical representations), this term refers to all the numbers stated, and in the case of numerical intervals, to both the first and second extreme values ​​of the interval.For example, a mentioned interval of "approximately X to Y" should be read as "approximately X to approximately Y".

[0108] Before proceeding to a brief description of the present invention, it should also be noted that several directional terms, such as upper, lower, upward, vertical, downward, and the like, have been used throughout this specification to provide context and clarity for the invention with reference to the normal vertical use of the system for estimating a lifted load, typically on a flat surface. These terms should not be taken as limiting the invention; they are used only in a particular orientation.

[0109] In various places in this document, values ​​are described in groups or ranges. It is specifically intended that the description include each and every member of such groups and ranges individually and in subcombinations, and any combination of the different extreme values ​​of such groups or ranges. For example, an integer in the range of 0 to 40 is specifically intended to individually describe 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, and 40, and an integer in the range of 1 to 20 is specifically intended to individually describe 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 and 20. The above also applies to decimal numbers with up to two decimal places, that is, up to the hundredth.

[0110] To designate intervals and / or ranges, various expressions can be used, such as "X - Y", "from X to Y", "from X to Y", "from X - Y", "between X and Y", and others used for this purpose.

[0111] Although this application mentions separate modes of implementation, it should be understood that any mode of implementation, and its characteristic features, may be freely combined with any other mode of implementation and its characteristic features, even in the absence of an explicit statement to that effect. It should be understood that the order of the steps or the order in which certain actions are performed is irrelevant as long as these teachings remain operative.

[0112] Furthermore, two or more steps or actions may be performed simultaneously. The use of any and all examples, or exemplary language in this document, such as "as" or "including," is intended solely to better illustrate the disclosure herein and does not limit the scope of the invention unless expressly stated. Nothing in the description should be construed as indicating that any unclaimed element is essential to the practice of the invention described herein. APPLICATION EXAMPLES

[0113] The following are examples of embodiments of the present invention. It should be understood that these examples are described to provide a better understanding of the present invention, but in no way limit the scope of the protection sought. Furthermore, details of technical features specified in different examples may be combined with each other, or with other previously described preferred embodiments, in any manner provided without limiting the scope of the present invention.

[0114] Lifting efficiency is defined as the ratio between the potential energy of the load and the electrical energy measured during the lifting process. Based on data obtained from 49 lifting tests with varying load levels (200 to 1200 kg), a linear relationship was established between lifting efficiency and the load transported, allowing for load estimation with an average error of 4.28%. This method enabled the implementation of alarms to ensure, for example, that the load transported does not exceed 70% of the nominal capacity, thereby improving occupational safety and the operational safety of the crane.

[0115] For this invention, tests were conducted using a lifting device: a Toyota® brand electric forklift, model FBMF-16. This forklift is an electro-hydraulically operated machine whose key electrical system components include the battery bank, traction motor, lifting motor, and power steering motor. It has a lifting capacity of up to 1600 kg and is equipped with a double mast that facilitates lifting loads up to 3.5 meters.

[0116] The battery bank consists of 40 lead-acid cells connected in series, allowing it to reach a nominal voltage of 80 V and a capacity of 450 Ah. The forklift has three direct current (DC) motors.

[0117] The series-wound DC motor, responsible for the traction system, generated the torque necessary for movement, transmitting it to the front tires via the transmission, thus enabling the forklift to move. This motor has a rated power of 8.6 kW and a rated voltage of 80 V. It has four connection terminals, as shown in Figure 1. Terminals A and B correspond to the armature circuit, while terminals E and F belong to the field circuit.

[0118] The series-wound DC hoist motor has a rated voltage of 80 V and a rated power of 13 kW. This motor powers the hydraulic pump, which provides the pressurized fluid necessary to drive the hydraulic actuator. This actuator controls the crane's hoist and tilt cylinders. Figure 2 identifies the DC motor's connection terminals: terminal A corresponds to the armature circuit supply and terminal F to the field circuit output. The permanent magnet DC power steering (PS) motor provides steering assistance, independent of the machine's load. It has a rated power of 1 kW and a rated voltage of 70 V. The motor is shown in Figure 3, where the power connector is highlighted in a rectangular frame.

[0119] The arrangement of the instruments used for data collection during crane operation is shown in Figure 4.

[0120] The SEFRAM DAS 60 data logger was used to measure and record electrical variables. Specifically, voltage and current signals were measured over time from the traction, hoist, and power steering motors at a sampling frequency of 50 kHz. An MR416 current probe was used to acquire the current signals.

[0121] A circuit was designed that repeats every two laps, for a total of 10 laps per applied load. Figure 5 shows a diagram of the test procedure. The movements within the circuit followed the guidelines of the VDI-2198 standard, adapted to the available space.

[0122] According to Figure 5, the distance between P1, P2, P3, and P4 is 30 meters, while between P2, P3, P4, and P1, there is a curve with a radius of 5 meters. In the loading area, maneuvers were performed to deposit or pick up the load, and in the lifting area, the load was lifted to an average height of 2 meters.

[0123] These tests allowed for the recording of electrical signals from the forklift's three motors under varying load conditions. For the traction motor and the power steering motor, no significant variations in electrical signals were observed across different load levels, so the analysis focused on the lifting motor.

[0124] The different load levels were implemented using two LBC tanks, shown in Figure 6a, which allowed the load weight to be adjusted by filling them with water. Load measurement was performed using a low-profile scale connected to an XK3190-A12 / A12E digital weighing indicator, shown in Figures 6b and 6c, respectively. A total of 11 load levels were established, ranging from 202.5 kg to 1202.0 kg, in approximate increments of 100 kg, as detailed in Table I. Due to the number of rotations performed during the tests, a total of 5 samples were obtained for each load level used on the hoist motor. Table I: Load levels per test

[0125] Test No. Load Level Load Level

[0126] — IES] _ [%] _

[0127] 1 202.5 12.66

[0128] 2 301.5 18.84

[0129] 3 404.5 25.28

[0130] 4 500.5 31.28

[0131] 5 600.0 37.50

[0132] 6 701,0 43,81

[0133] 7 800.5 50.03

[0134] 8 907.5 56.72

[0135] 9 1002.5 62.66

[0136] 10 1100,068,75

[0137] 11 1202,0 75 , 13

[0138] The forklift's lifting system motor is regulated by voltage control. This control is implemented using power electronics, specifically DC / DC converters. In a regulator employing this technique, a pulse-width modulation (PWM) signal is generated. The main function of this technique is to regulate and control the average voltage delivered to the motors by adjusting the ratio between the time the device is active (conduction period) and the time it remains inactive.

[0139] Due to this type of voltage pulse control, the recorded signals exhibit discontinuous operation oscillating between zero and the battery voltage, as shown in Figure 7. To obtain more representative signals in the analysis of these variables, a Butterworth low-pass filter is applied, which allowed the identification of the transient and steady states in the operation of the lifting motor.

[0140] Figure 8 shows the difference between the original signal and the filtered signal of the electrical power supplied to the lifting motor during testing.

[0141] From the filtered power signals, the cumulative energy consumption during the load lifting process was calculated, given that the same lifting height was used in all tests. Figure 9 shows an example of electrical power measurement for lifting (a) without a load and (b) with a 202.5 kg load. For these tests, a lifting height of 2 m was defined. From these power measurements, the electrical energy consumed in the process (EEL) is obtained, which is shown in Figure 10 (a) without a load and (b) with a 202.5 kg load. For the calculation of the energy consumed (EEL), the cumtrapz function of MATLAB® was used, which approximates the cumulative integral using the trapezoidal method, considering the spacing between the units of the electrical power signal supplied to the lifting motor.

[0142] The weight and lifting height were known and the lifting potential energy (LPE) was calculated for each reference load used in the tests, as shown in Table I:

[0143]

[0144] Where m is the mass transported, g is the gravitational acceleration constant, and h is the height of the load being lifted.

[0145] Knowing the potential energy and the electrical energy supplied to the lifting motor (EEL), calculated from the measured electrical voltage and current signals, it is possible to obtain a lifting efficiency (EFF) value using the following formula:

[0146]

[0147] EFF EL

[0148] Subsequently, a graph was constructed showing the lifting efficiency values ​​as a function of the median electrical power of the lifting device (also measured from the voltage and current sensors). Figure 12 presents the graph of Lifting Efficiency (EFF) versus the median electrical power, considering a total of 49 samples. Values ​​corresponding to a load of 0 kg, as well as outliers that deviated significantly from the average for each load level, were discarded.

[0149] A linear trend line was incorporated in Figure 12, yielding a coefficient of determination of 0.9. This indicates that 90% of the variability in lifting efficiency can be explained by the variability in the median electrical power measured at the motor's power terminals. This result suggests that, as the median power varies, it is possible to predict with reasonable accuracy how the efficiency will change using this linear relationship.

[0150] The equation that allows calculating the lifting efficiency from the median power (Pmed) measured as follows:

[0151] FF2 = 0.00003 * Pmed — 0.0528 Once the estimated efficiency (EFF) is known, the estimated potential lift energy (EPL) can be calculated from the electrical lift energy (EEL) measured by the voltage and current sensors:

[0152] EPL2 = EFF2 * EEL

[0153] With this new value for potential energy, it is possible to calculate the estimated mass transported (m2) from the estimated potential energy of elevation, using the following formula:

[0154]

[0155] In these tests, a gravitational acceleration constant of 9.81 N was considered. 2 / kg 2 With a lifting height of 2 meters, an average mass estimation error of 4.28% was obtained across 49 tests. The maximum observed error was 27.33%, when the transported mass was 800.5 kg and the estimated mass was 1019.3 kg. The minimum observed error was -15.4%, when the transported mass was 301.5 kg and the estimated mass was 255.03 kg.

[0156] The method of the present invention made it possible to estimate the load carried by an electric forklift, helping the operator to avoid exceeding 70% of the machine's rated load. This contributes to improved safety for both the operator and the forklift, preventing mechanical problems, rollovers, work delays, and / or workplace accidents.

[0157] Knowing the weight capacity of forklifts not only allows for more efficient use of this equipment but also contributes to safer operation. Furthermore, by promoting the use of electric machinery instead of combustion-powered machinery, a more sustainable industrial activity is fostered and the carbon footprint is reduced.

[0158] Moreover, as shown in Figure 11, this method and system not only provides an accurate estimate of load weight but also utilizes data from electric motors in general to overcome the limitations of traditional sensors. This improves the crane's energy efficiency, increases operational safety, and promotes more sustainable use of electric machinery. Furthermore, the ability to transmit data over the internet allows companies to monitor their machines' energy consumption online and in real time, and make adjustments to optimize processes, generating savings in operating time and promoting a more efficient and safer system.

Claims

CLAIMS 1. A method for estimating a load lifted by lifting means driven by an electric motor and / or electric motion generation means, independent of the drive method and / or the lifting speed of the load, to maintain operational safety, CHARACTERIZED in that it comprises: a) initiate a calibration stage, where the calibration stage comprises: i. provide a first load that has a known mass and is to be lifted to a predetermined calibration height during at least two calibration lifting operations; i. actuate lifting means by means of at least one electrical motion generation means to lift the first load; iii. measure a current as a function of time and a voltage as a function of time of at least one electrical motion generation means during at least two calibration lifting operations of the first load to the calibration height; iv. obtain an electrical power as a function of time from at least one means of generating electrical motion during the at least two calibration lifting operations of the first load to the calibration height from the current as a function of time and the voltage as a function of time; v. obtain an energy consumed (EEL) by at least one means of generating electrical motion during each of the at least two calibration lifting operations from the electrical power as a function of time; and vi. obtain at least two lifting efficiency (EFF) values ​​from the comparison between the energy consumed (EEL) during each of the at least two calibration lifting operations and a lifting potential energy (EPL) associated with the known mass and calibration height; b) obtain, from the at least two lifting efficiency (EFF) values ​​obtained during the at least two calibration lifting operations, a relationship between an estimated lifting efficiency value (EFF2) and a characteristic value of electrical power as a function of time; c) start a work operation, which comprises: i. provide at least a second load with an unknown mass to be lifted to a predefined working height (IIT) during at least one working lifting operation; i. drive the lifting means through at least one electrical motion generation means to lift the second load; iii. measure a working current as a function of time and a working voltage as a function of time of at least one electrical motion generation means during at least one working lifting operation of the second load to the predefined working height (hy); iv. obtaining a time-dependent electrical working power from at least one means of generating electrical motion during at least one working lifting operation of the second load to the predefined working height (IIT) from the time-dependent working current and the time-dependent working voltage; and v. obtain an energy of work consumed (EELT) by at least one means of generating electrical motion during each of the at least one work lifting operation from the electrical work power as a function of time; d) obtain, from the relationship obtained in step b) and the work energy consumed (EELT) obtained in step c), an estimated potential energy of lift (EPL2); and e) determine an estimated mass (m e ) of the second load, based on the estimated lifting potential energy (EPL2), to maintain operational safety.

2. The conformity estimation method according to claim 1, CHARACTERIZED in that the calibration step a), from sub-step i to vi, is performed iteratively, and wherein the mass of the first load is modified in a known manner for each iteration of the calibration step a).

3. The conformity estimation method according to claim 2, CHARACTERIZED in that for each iteration of the calibration stage a) the mass of the first load is modified with constant mass differentials.

4. The conformity estimation method according to any one of claims 1 to 3, CHARACTERIZED in that the calibration step a), from sub-step i to vi, is performed iteratively, and wherein the calibration height is modified in a known manner for each iteration of the calibration step a).

5. The conformity estimation method according to claim 4, CHARACTERIZED in that for each iteration of the calibration stage a) the calibration height is modified with constant height differentials.

6. The method of estimating conformity with any one of claims 1 to 5, CHARACTERIZED in that the lifting action is performed with at least one lifting means which is an electric motor of at least one phase.

7. The method of estimating conformity with claim 1, CHARACTERIZED in that it comprises repeating steps c) to e) iteratively for each new load that is lifted.

8. The conformity estimation method according to claim 1, CHARACTERIZED in that in step a) and in step c) the actuation of the lifting means is carried out by means of an actuator.

9. The conformity estimation method according to the preceding claim, CHARACTERIZED in that in step a) and in step c) the drive of the lifting means carried out through the actuator is variable.

10. The estimation method according to claim 1, CHARACTERIZED in that in sub-step iv of step a), obtaining the at least two lifting efficiency (EFF) values ​​from the comparison between the energy consumed (EEL) during the at least two calibration lifting operations and a lifting potential energy (EPL) associated with the known mass and calibration height, is done through EFF = EPL / EEL.

11. The estimation method according to claim 1, CHARACTERIZED in that in step e), the estimated mass (m e ) is obtained through m e = (EPL2) / (g ■ T), where g is the acceleration due to gravity.

12. The estimation method according to claim 1, CHARACTERIZED in that in step b), the relationship between the estimated lifting efficiency value (EFF2) and the characteristic value of electrical power as a function of time is obtained by regression.

13. The estimation method according to claim 12, CHARACTERIZED in that the regression is linear.

14. The estimation method according to claim 12, CHARACTERIZED in that the regression is non-linear (quadratic, exponential, logarithmic, power, polynomial) 15. The estimation method in accordance with any one of claims 12 to 14, CHARACTERIZED in that the characteristic value of the electrical power as a function of time corresponds to the median of the electrical power as a function of time.

16. The estimation method according to claim 1, CHARACTERIZED in that the current as a function of time and the voltage as a function of time are measured by means of measuring devices, wherein the measuring devices are measuring equipment selected from: current probes, voltage probes, multimeter, ammeter, voltmeter, oscilloscope, among others.

17. The estimation method according to claim 1, CHARACTERIZED in that the work operation c) further comprises in stage 11: measure a second operating current as a function of time and a second operating voltage as a function of time of at least one second means of generating electrical motion during at least one displacement operation of the second load, to determine more accurately the estimated mass (m e ) of the second load.

18. The conformity estimation method according to claim 17, CHARACTERIZED in that the work operation c) further comprises in stage ill: measure acceleration variations through an IMU.

19. The conformity estimation method according to claim 1, CHARACTERIZED in that the work operation e) further comprises activating an alarm when the transported load exceeds at least 50% of a nominal capacity.

20. The conformity estimation method according to claim 19, CHARACTERIZED in that the work operation e) further comprises activating the alarm when the transported load exceeds at least 70% of the nominal capacity.

21. A system for estimating a load lifted by lifting means powered by an electric motor and / or electric motion generation means, independent of the method of drive and / or the lifting speed of the load, in order to maintain operational safety, CHARACTERIZED in that: a base structure comprising lifting means operatively connected to said base structure and at least one electrical motion generating means rigidly connected to the base structure and further said at least one electrical motion generating means operatively connected to the lifting means for lifting at least one load during at least one calibration or work lifting operation; a power source electrically connected to it at least one means of generating electrical motion; means for measuring current as a function of time and voltage as a function of time, electrically connected to the means for generating electrical motion; one or more processors connected to the time-dependent current and time-dependent voltage measurement means, comprising a display means, at least one human interface, and one or more processors implemented in circuits and communicatively coupled to a memory that are configured to execute the following steps: a) initiate a calibration stage, where the calibration stage comprises: i. provide a first load that has a known mass and is to be lifted to a predetermined calibration height during at least two calibration lifting operations; i. actuate the lifting means by means of at least one electrical motion generation means to lift the first load; iii. measure a current as a function of time and a voltage as a function of time of at least one electrical motion generation means during at least two calibration lifting operations of the first load to the calibration height; iv. obtain an electrical power as a function of time from at least one means of generating electrical motion during the at least two calibration lifting operations of the first load to the calibration height from the current as a function of time and the voltage as a function of time; v. obtain an energy consumed (EEL) by at least one means of generating electrical motion during each of the at least two calibration lifting operations from the electrical power as a function of time; and vi. obtain at least two lifting efficiency (EFF) values ​​from the comparison between the energy consumed (EEL) during each of the at least two calibration lifting operations and a lifting potential energy (EPL) associated with the known mass and calibration height; b) obtain, from the at least two lifting values ​​obtained during the at least two calibration lifting operations, a relationship between an estimated lifting efficiency value (EFF2) and a characteristic value of electrical power as a function of time; c) start a work operation, which comprises: i. provide at least a second load with an unknown mass to be lifted to a predefined working height (Irr) during at least one working lifting operation; i. actuate the lifting means through at least one electrical motion generating means to lift the second load; iii. measure a working current as a function of time and a working voltage as a function of time of the at least one electrical motion generating means during the at least one working lifting operation of the second load to the predefined working height (hy); iv. obtaining a time-dependent electrical working power from at least one means of generating electrical motion during at least one working lifting operation of the second load to the predefined working height (IIT) from the time-dependent working current and the time-dependent working voltage; and v. obtain an energy of work consumed (EELT) by at least one means of generating electrical motion during each of the at least one work lifting operation from the electrical work power as a function of time; d) obtain, from the relationship obtained in step b) and the work energy consumed (EELT) obtained in step c), an estimated potential energy of lift (EPL2); and e) determine an estimated mass (m e ) of the second load, based on the estimated lifting potential energy (EPL2), to maintain operational safety.

22. The conformity estimation system of claim 21, CHARACTERIZED in that the means for measuring current as a function of time and voltage as a function of time are measuring equipment selected from: ampere probes, voltage probes, multimeter, ammeter, voltmeter, oscilloscope, among others. (The data is transferred wirelessly to the billing and warehouse management systems) 23. The conformity estimation system according to claim 21, CHARACTERIZED in that the at least one lifting means is an electric motor of at least one phase.

24. The conformity estimation system according to claim 21, CHARACTERIZED in that the at least one lifting means is a direct current (DC) electric motor.

25. The conformity estimation system according to claim 21, CHARACTERIZED in that the at least one lifting means is an alternating current (AC) electric motor.

26. The conformity assessment system of claim 21, CHARACTERIZED in that it further comprises an alarm that is selected from among an audible, vibrating, and / or visual alarm.

27. A non-transient, computer-readable storage medium CHARACTERIZED in that it stores instructions which, when executed, cause one or more processors to perform the following steps: a) initiate a calibration stage, where the calibration stage comprises: i. provide a first load that has a known mass and is to be lifted to a predetermined calibration height during at least two calibration lifting operations; i. actuate lifting means by means of at least one electrical motion generation means to lift the first load; iii. measure a current as a function of time and a voltage as a function of time of at least one electrical motion generation means during at least two calibration lifting operations of the first load to the calibration height; iv. obtain an electrical power as a function of time from at least one means of generating electrical motion during the at least two calibration lifting operations of the first load to the calibration height from the current as a function of time and the voltage as a function of time; v. obtain an energy consumed (EEL) by at least one means of generating electrical motion during each of the at least two calibration lifting operations from the electrical power as a function of time; and vi. obtain at least two lifting efficiency (EFF) values ​​from the comparison between the energy consumed (EEL) during each of the at least two calibration lifting operations and a lifting potential energy (EPL) associated with the known mass and calibration height; b) obtain, from the at least two lifting efficiency values ​​obtained during the at least two calibration lifting operations, a relationship between an estimated lifting efficiency value (EFF2) and a characteristic value of electrical power as a function of time; c) start a work operation, which comprises: i. provide at least a second load with an unknown mass to be lifted to a predefined working height (Irr) during at least one working lifting operation; i. actuate the lifting means through at least one electrical motion generating means to lift the second load; iii. measure a working current as a function of time and a working voltage as a function of time of the at least one electrical motion generating means during the at least one working lifting operation of the second load to the predefined working height (hy); iv. obtaining a time-dependent electrical working power from at least one means of generating electrical motion during at least one working lifting operation of the second load to the predefined working height (IIT) from the time-dependent working current and the time-dependent working voltage; and v. obtain an energy of work consumed (EELT) by at least one means of generating electrical motion during each of the at least one work lifting operation from the electrical work power as a function of time; d) obtain, from the relationship obtained in step b) and the work energy consumed (EELT) obtained in step c), an estimated potential energy of lift (EPL2); and e) determine an estimated mass (m e ) of the second load, based on the estimated lifting potential energy (EPL2), to maintain operational safety.

Images