CN118194451A - Dynamic weighing calculation method and system for excavator - Google Patents
Dynamic weighing calculation method and system for excavator Download PDFInfo
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Abstract
The invention discloses a dynamic weighing calculation method and a dynamic weighing calculation system for an excavator, wherein the method comprises the following steps: acquiring the body excavation parameters of the excavator, and establishing a static weighing model of the excavator when the excavator is in idle load; nonlinear regression is carried out on a static weighing model of the excavator in a data calibration mode, so that an identification model coefficient is obtained; acquiring dynamic excavation parameters of the excavator, and establishing a dynamic weighing model of the excavator; and calculating the load weight of the excavator in the action process according to the established static weighing model, identification model coefficient and dynamic weighing model of the excavator. The influence of the gravity center change of the tool on the weighing precision is directly avoided; on the basis of realizing a static model, the influence caused by parameters such as acceleration speed, moment of inertia and the like in the dynamic loading process is greatly reduced on the basis of coefficient regression of a dynamic model; in the specific loading gesture range process of the excavator, the stable area of the large arm oil cylinder is automatically identified, and the weighing of the load of the excavator is dynamically realized under each stable working period.
Description
Technical Field
The invention relates to the technical field of excavator weighing, in particular to a dynamic weighing calculation method and system for an excavator.
Background
At present, most of domestic hydraulic excavators are not provided with an on-line metering device in the process of picking, loading and transporting, and the hydraulic excavators rely on truck transportation wagon balance off-line weighing. In the prior art, the weight of the excavated material in the excavator bucket is obtained through calculation of sensor parameters and gravity center structural parameters, and as the gravity center of the tool changes in real time in the dynamic loading process of the excavator, the influence caused by parameters such as the speed of an oil cylinder, friction force and the like is not considered, a large amount of measurement errors are introduced, and the overall weighing error is larger.
Disclosure of Invention
In order to solve part or all of the technical problems in the prior art, the invention provides a dynamic weighing calculation method and a dynamic weighing calculation system for an excavator, which avoid the influence of the change of parameters such as gravity center, speed and the like when the excavator is dynamically weighed, realize the dynamic weighing of the excavator under a specific gesture and greatly improve the weighing measurement precision.
The technical scheme of the invention is as follows:
in a first aspect, the present invention provides a method for calculating dynamic weighing of an excavator, including:
Acquiring the body excavation parameters of the excavator, and establishing a static weighing model of the excavator when the excavator is in idle load;
Nonlinear regression is carried out on a static weighing model of the excavator in a data calibration mode, so that an identification model coefficient is obtained;
acquiring dynamic excavation parameters of the excavator, and establishing a dynamic weighing model of the excavator;
and calculating the load weight of the excavator in the action process according to the established static weighing model, identification model coefficient and dynamic weighing model of the excavator.
Further, the fuselage parameters include: boom angle α, stick angle β, and bucket angle γ.
Further, the static weighing model of the excavator in no-load is as follows:
MEmpty＝(W1*x1+W2*G+W3*G)*cosα-(W1*y1)*sinα+(W2*x2+W3*I)*cosβ-(W2*y2)*sinβ+(W3*x3)*cosβ-(W3*y3)*sinβ
Wherein W 1 represents the mass of the large arm of the excavator; w 2 represents the mass of the excavator bucket rod; w a represents the excavator bucket mass; i represents the distance from the hinge point of the head of the excavator bucket to the hinge point of the head of the big arm; g represents the distance from the hinge point of the head of the large arm of the excavator to the rear hinge point of the large arm; x 1,x2,x3 respectively represents the abscissa of the gravity center of the large arm, the bucket rod and the bucket; y 1,y2,y3 represents the ordinate of the gravity center of the big arm, the bucket rod and the bucket respectively;
Further, the identification model coefficients include a, B, C, D, E, and F, and the identification model coefficients are static model coefficients, wherein:
A*＝W1*x1+W2*G+W3*G；
B*＝W1*y1；
C*＝W2*x2+W3*I；
D*＝W2*y2；
E*＝W3*x3；
F*＝W3*y3；
in the above formula, W 1 represents the excavator boom mass; w 2 represents the mass of the excavator bucket rod; w 3 represents the excavator bucket mass; i represents the distance from the hinge point of the head of the excavator bucket to the hinge point of the head of the big arm; g represents the distance from the hinge point of the head of the large arm of the excavator to the rear hinge point of the large arm; x 1,x2,x3 respectively represents the abscissa of the gravity center of the large arm, the bucket rod and the bucket; y 1,y2,y3 represents the ordinate of the center of gravity of the boom, stick, and bucket, respectively.
Further, when data calibration is carried out, the excavator is set to be in a low gear or an initial gear, the excavator is started, and when the temperature of hydraulic oil reaches 45-60 ℃, the bucket rod and the large arm are calibrated respectively, wherein the calibration conditions are as follows:
The angle of the big arm is adjusted to 26 degrees+/-0.2 degrees, the angle of the bucket rod is adjusted to-100 degrees+/-0.2 degrees, and the bucket cylinder is shortened to the shortest time;
The angle of the large arm is adjusted to 26 degrees+/-0.2 degrees, the bucket rod oil cylinder is contracted to the shortest, and the bucket oil cylinder extends to the longest;
the angle of the big arm is adjusted to 17 degrees+/-0.2 degrees, the angle of the bucket rod is-104 degrees+/-0.2 degrees, the bucket cylinder is contracted to the longest, and the big arm is lifted to the bottom.
Further, the dynamic excavation parameters of the excavator include a hydraulic cylinder static friction coefficient, a viscous friction coefficient, a hydraulic cylinder pressure, a hydraulic cylinder inclination angle, a hydraulic cylinder speed, and a hydraulic cylinder resultant force.
Further, the hydraulic cylinder resultant force is: f Closing device ＝Pnrod*A2-Prod*A1; wherein P nrod represents: variable amplitude cylinder rodless cavity pressure (Pa); p rod represents: the amplitude variation oil cylinder has rod cavity pressure (Pa); a 2 represents: the effective area of the rodless cavity of the amplitude variation oil cylinder; a 1 represents: the amplitude variation oil cylinder has a rod cavity effective area.
Further, the load weight calculation model in the excavator action process is as follows:
Wherein: l radius represents: bucket load center of gravity is on the abscissa under the XOY coordinate system; p nrod represents: the pressure of the rodless cavity of the amplitude variable oil cylinder; a 2 represents: the effective area of the rodless cavity of the amplitude variation oil cylinder; p rod represents: the amplitude variation oil cylinder has rod cavity pressure; a 1 represents: the effective area of the rod cavity of the amplitude variation oil cylinder; f k denotes: static friction force of the oil cylinder; ; f v denotes: the viscosity friction coefficient of the oil cylinder; v represents: linear velocity of the amplitude variation cylinder; calc B denotes: the straight line intercept of the large arm oil cylinder under the XOY coordinate; calc K denotes: the slope of a straight line of the large arm cylinder under the XOY coordinate; a, B, C, D, E, F represent: static model coefficients; alpha represents: a large arm angle; beta represents: angle of the bucket rod.
In a second aspect, the present invention also provides a excavator dynamic weighing computing system comprising:
the static weighing model building module is used for obtaining the body excavation parameters of the excavator and building a static weighing model of the excavator when the excavator is in idle load;
The identification model coefficient acquisition module is used for carrying out nonlinear regression on the static weighing model of the excavator in a data calibration mode to obtain an identification model coefficient;
the dynamic weighing model building module is used for obtaining dynamic excavating parameters of the excavator and building a dynamic weighing model of the excavator;
and the load weight calculation module is used for calculating the load weight in the action process of the excavator according to the established static weighing model, the identification model coefficient and the dynamic weighing model of the excavator.
The technical scheme of the invention has the main advantages that:
According to the excavator dynamic weighing calculation method, the static weighing model is built by acquiring the body parameters of the excavator, the dynamic parameters of the excavator are acquired, the dynamic weighing model of the excavator is built, the static balance equation is built by using the hinge points of the large-arm vehicle body, the static model is subjected to nonlinear regression through data calibration, the static model coefficient is identified, and the influence of the gravity center change of the tool on the weighing precision is directly avoided; on the basis of realizing a static model, the influence caused by parameters such as acceleration speed, moment of inertia and the like in the dynamic loading process is greatly reduced on the basis of coefficient regression of a dynamic model; in the specific loading gesture range process of the excavator, the stable area of the large arm oil cylinder is automatically identified, and the weighing of the load of the excavator is dynamically realized under each stable working period.
Drawings
The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and without limitation to the invention. In the drawings:
FIG. 1 is a flow chart of a method for calculating dynamic weighing of an excavator according to an embodiment of the present invention;
Fig. 2 is a schematic structural diagram of building corresponding coordinates and setting related parameters on an excavator when building a dynamic weighing model and a static weighing model in the method for calculating dynamic weighing of an excavator according to an embodiment of the present invention;
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments of the present invention and corresponding drawings. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The following describes in detail the technical scheme provided by the embodiment of the invention with reference to the accompanying drawings.
1-2, An embodiment of the invention provides a dynamic weighing calculation method for an excavator, which comprises the following steps:
Acquiring the body excavation parameters of the excavator, and establishing a static weighing model of the excavator when the excavator is in idle load;
Nonlinear regression is carried out on a static weighing model of the excavator in a data calibration mode, so that an identification model coefficient is obtained;
acquiring dynamic excavation parameters of the excavator, and establishing a dynamic weighing model of the excavator;
and calculating the load weight of the excavator in the action process according to the established static weighing model, identification model coefficient and dynamic weighing model of the excavator.
The principle of the excavator dynamic weighing calculation method is that the geometrical information of the load position and the hydraulic cylinder pressure are obtained by utilizing the angle and the pressure sensor, an equation is established through a moment balance principle, and the load weight is calculated, so that the load is dynamically weighed under each normal working period; the known input comprises structural parameter input, sensor input (angle and pressure), no-load moment, an oil cylinder force arm and an oil cylinder force are calculated, parameters are identified through static coefficient calibration and dynamic coefficient calibration, and finally weight is solved through actual moment, no-load moment and amplitude.
Specifically, the body parameters include at least a boom angle α, an arm angle β, and a bucket angle γ when performing static weighing model calculations when the excavator is empty.
The boom angle α, the arm angle β, the bucket angle γ, the vehicle body horizontal inclination angle δ, and the structural parameters are known, and thus are known amounts, because the model and the size of the excavator are known. When the static weighing model and the dynamic weighing model are built, a hinge point of the large arm and the vehicle body is used as an origin O of an absolute coordinate system, the right front is the positive direction of a horizontal axis X, and the right upper is the positive direction of a vertical axis Y, so that a two-dimensional coordinate system is built. Meanwhile, in order to facilitate calculation and construction of a static weighing model and a dynamic weighing model, a plurality of points and a plurality of dimensions are arranged on the excavator and are used for assisting calculation, as shown in fig. 2, A represents the horizontal distance from a rotation center shaft to a rear hinge point of a large arm, and B represents the vertical height from the rear hinge point of the large arm to the ground; c represents the horizontal distance from the lower hinge point of the large arm cylinder to the rear hinge point of the large arm; d represents the vertical height from the lower hinge point of the large arm oil cylinder to the ground; e represents the horizontal distance from the hinge point on the large arm cylinder to the hinge point behind the arm; f represents the vertical height from the hinge point on the large arm oil cylinder to the ground; g represents the distance from the hinge point of the head of the big arm to the rear hinge point of the big arm, namely the length of the big arm; h represents the vertical height from the hinge point of the head of the large arm to the ground; i represents the distance from the hinge point of the head of the bucket rod to the hinge point of the head of the large arm, namely the length of the bucket rod; θ represents the initial angle between the connecting line of the upper hinge point of the large arm cylinder and the rear hinge point of the large arm and the horizontal when α is 0 degrees; w1 represents the boom mass (kg); w2 represents the arm mass (kg); w3 represents bucket mass (kg); therefore, the coordinates of the upper hinge point and the lower hinge point of the large arm cylinder are (calc_UP_X, calc_UP_Y) and (C, D-B) according to the rotation matrix.
In some alternative implementations of the present embodiment, as shown in fig. 2, points denoted by P1, P2, P3, and P4 are tilt sensors mounted on the boom, stick, rocker, and body, respectively, and the boom angle α, stick angle β, and bucket angle γ, and body horizontal tilt δ can be calculated from the numerical and structural geometry thereof.
It should be noted that α represents the included angle between the connecting line from the hinge point of the head of the large arm to the hinge point of the rear of the large arm and the horizontal angle; beta represents the horizontal included angle between the connecting line from the hinge point of the head of the bucket rod to the hinge point of the head of the large arm; gamma represents the horizontal included angle between the connecting line of the hinge point of the head of the bucket rod and the tooth tip of the bucket; the alpha, beta and gamma angles are positive on the horizontal line and negative on the lower line. In the invention, the horizontal inclination angle |delta| is less than or equal to 2 degrees based on the double axes of the vehicle body X and Y.
Also to be described is: the above parameters are obtained with the excavator boom α=0° and the arm cylinder retracted to the bottom and the bucket extended to the bottom.
Therefore, the calculated coordinates of the hinge point on the large arm oil cylinder are as follows:
Calc_UP_x＝E*cos(α+θ)-(F-B)sin(α+θ)；
Calc_UP_Y＝E*sin(α+θ)-(F-B)cos(α+θ)；
Considering that the vertical and horizontal condition exists when the large arm oil cylinder stretches and contracts under the coordinate, namely the slope of the connecting line of the upper hinge point and the lower hinge point of the large arm oil cylinder is Calc_K which is 0; so if calc_up_x=c, calc_k=0; whereas the slope is calck and the intercept is calcb.
In summary, the perpendicular line distance from the back twisting point of the main arm to the straight line of the upper twisting point and the lower twisting point of the oil cylinder can be obtained. Specifically, the principle of point-to-straight distance: knowing the point (a, b) straight line ax+by+c=0, distanceObtaining the productNamely the arm of force from the rear hinge point of the large arm to the force of the large arm cylinder. The far point O is selected as a balance point, so that the moment M oil＝F Closing device of the large arm oil cylinder to the original point O is equal to d.
In some optional implementation manners of this embodiment, a hinge point on the arm and the boom is selected to be O 1; the connecting line of the hinge points on the bucket rod and the large arm and the hinge point of the bucket rod and the bucket is an X axis, and the axis perpendicular to the X 1 in the tool plane is a Y 1 axis. The hinge point of the bucket rod and the bucket is selected as O 2,O2, the connecting line of the tooth heel is selected as X 2 axis, and the Y 2 axis perpendicular to the X 2 axis is selected as shown in figure 2, so that X 1O1Y1 and X 2O2Y2 are relative coordinate systems. The structural member boom, stick, and bucket center of gravity are assumed to be (x, y), (x 1,y1), and (x 2,y2) in order. The no-load moment is:
MEmpty＝W1*(x1*cosα-y1*sinα)+W2*(G*cos+x2*cosβ-y2*sinβ)+W3*(G*cosα+I*cosβ+x3*cosγ-y3*sinγ);
simplifying the above method, and obtaining a static weighing model of the excavator when the excavator is in no-load state, wherein the static weighing model is as follows:
MEmpty＝(W1*x1+W2*G+W3*G)*cosα-(W1*y1)*sinα+(W2*x2+W3*I)*cosβ-(W2*y2)*sinβ+(W3*x3)*cosβ-(W3*y3)*sinβ;
Wherein W1 represents the mass of the large arm of the excavator; w 2 represents the mass of the excavator bucket rod; w 3 represents the excavator bucket mass; i represents the distance from the hinge point of the head of the excavator bucket to the hinge point of the head of the big arm; g represents the distance from the hinge point of the head of the large arm of the excavator to the rear hinge point of the large arm; x 1,x2,x3 respectively represents the abscissa of the gravity center of the large arm, the bucket rod and the bucket; y 1, y2, y3 represent the ordinate of the center of gravity of the boom, stick, bucket, respectively.
Specifically, the identification model coefficients include a, B, C, D, E, and F, and the identification model coefficients are static model coefficients, wherein:
A*＝W1*x1+W2*G+W3*G；
B*＝W1*y1；
C*＝W2*x2+W3*I；
D*＝W2*y2；
E*＝W3*x3；
F*＝W3*y3；
In the above formula, W 1 represents the excavator boom mass; w 2 represents the mass of the excavator bucket rod; w 3 represents the excavator bucket mass; i represents the distance from the hinge point of the head of the excavator bucket to the hinge point of the head of the big arm; g represents the distance from the hinge point of the head of the large arm of the excavator to the rear hinge point of the large arm; x 1,x2,x3 respectively represents the abscissa of the gravity center of the large arm, the bucket rod and the bucket; y 1, y2, y3 represent the ordinate of the center of gravity of the boom, stick, bucket, respectively.
Substituting the identification model coefficient into the simplified static weighing model of the excavator in no-load state to obtain the following steps:
MEmpty＝A*cosα-B*sinα+C*cosβ-D*sinβ+E*cosβ-F*sinβ；
in some optional implementation manners of the embodiment, in order to better establish a static weighing no-load moment model of the excavator, the model coefficient A, B, C, D, E, F is obtained by low gear calibration, and the bucket calibration, the bucket rod calibration and the large arm calibration are included in the calibration, and the data acquisition data are obtained to perform reverse thrust on the digital model, so that model parameters are regressed and identified, and model residual errors are reduced.
Specifically, when data calibration is carried out, the excavator is set to be in a low gear or an initial gear, the excavator is started, and when the temperature of hydraulic oil reaches 45-60 ℃, the bucket rod and the large arm are calibrated respectively, wherein the calibration conditions are as follows:
The angle of the big arm is adjusted to 26 degrees+/-0.2 degrees, the angle of the bucket rod is adjusted to-100 degrees+/-0.2 degrees, and the bucket cylinder is shortened to the shortest time;
The angle of the large arm is adjusted to 26 degrees+/-0.2 degrees, the bucket rod oil cylinder is contracted to the shortest, and the bucket oil cylinder extends to the longest;
the angle of the big arm is adjusted to 17 degrees+/-0.2 degrees, the angle of the bucket rod is-104 degrees+/-0.2 degrees, the bucket cylinder is contracted to the longest, and the big arm is lifted to the bottom.
It should be noted that, when calibrating, still need to park the vehicle as far as horizontal position and firm place, from this, can further ensure the stability and the accuracy of the data that acquire in the in-process of calibration, and then ensure the reliability and the accuracy of the structure that demarcates.
In some alternative implementations of the present embodiment: when the calibration is performed, the gear of the throttle can be set to be 1 gear.
Specifically, the dynamic excavation parameters of the excavator include a hydraulic cylinder static friction coefficient, a viscous friction coefficient, a hydraulic cylinder pressure, a hydraulic cylinder inclination angle, a hydraulic cylinder speed, and a hydraulic cylinder resultant force.
Under the condition of constant load, the moment of the luffing cylinder can change along with the change of factors such as the speed, the friction force and the like of the movable arm. Dynamic weighing requires a secondary dynamic compensation of the effect of these factors on the weighing system. Through actual verification, the dynamic weighing is mainly related to friction force; the friction model comprises the factors of hydraulic cylinder speed (m/s), hydraulic cylinder resultant force (N) and the like;
specifically, the hydraulic cylinder friction force includes two parts: (1) static friction; (2) Dynamic friction force, which is related to the hydraulic cylinder static friction coefficient, viscous friction coefficient, hydraulic cylinder pressure, hydraulic cylinder inclination angle, and hydraulic cylinder speed;
f＝f Static state +f Dynamic movement ；
Wherein f represents: cylinder friction, including static friction and dynamic friction (coulomb friction); f Static state denotes: static friction force of the oil cylinder; f Dynamic movement denotes: and (5) oil cylinder dynamic friction force.
The static friction force of the luffing cylinder is related to the cylinder pressure, the cylinder inclination angle and the cylinder friction coefficient, and is shown in the following formula:
Wherein F Closing device represents: the resultant force (N) of the oil cylinder is shown in the following formula; wherein the method comprises the steps of The representation is: the inclination angle of the amplitude variation oil cylinder; f k denotes: coefficient of friction.
Specifically, F Closing device is: f Closing device ＝Pnrod*A2-Prod*A1;
In the above formula, P nrod represents the boom cylinder rodless cavity pressure (Pa); p rod represents the boom cylinder cavity pressure (Pa); a 2 represents the effective area of a rodless cavity of the amplitude cylinder; a 1 represents the effective area of the rod cavity of the amplitude cylinder.
Specifically, because the dynamic friction force of the amplitude variation oil cylinder is related to the linear speed of the hydraulic cylinder and the viscosity friction coefficient of the hydraulic cylinder, the hydraulic linear speed is obtained by a mathematical model from the angular speed of the large arm; the following formula is shown:
f Dynamic movement ＝fv*v；
Wherein f Dynamic movement represents: cylinder kinetic friction force (N); v represents: linear velocity of the amplitude variation cylinder; f v denotes: viscosity friction coefficient of the oil cylinder.
In summary, the bucket excavator weighing dynamic compensation model is shown in the following formula, and f k and f v are obtained through sample acquisition data identification; the moment loss caused by friction force is available, namely the bucket excavator is weighed and compensated;
Order the
Obtaining:
In the above formula, P nrod represents: variable amplitude cylinder rodless cavity pressure (Pa); p rod represents: the amplitude variation oil cylinder has rod cavity pressure (Pa); a 2 represents: the effective area of the rodless cavity of the amplitude variation oil cylinder; a 1 represents: the effective area of a rod cavity of the amplitude variation oil cylinder is W1, and the mass of a large arm of the excavator is represented; w 2 represents the mass of the excavator bucket rod; w 3 represents the excavator bucket mass; i represents the distance from the hinge point of the head of the excavator bucket to the hinge point of the head of the big arm; g represents the distance from the hinge point of the head of the large arm of the excavator to the rear hinge point of the large arm; x 1,x2,x3 respectively represents the abscissa of the gravity center of the large arm, the bucket rod and the bucket; y 1,y2,y3 represents the ordinate of the center of gravity of the boom, the arm and the bucket, and f k represents: static friction force of the oil cylinder; f v denotes: the viscosity friction coefficient of the oil cylinder; v represents: linear velocity of the amplitude variation cylinder; calc B denotes: the straight line intercept of the large arm oil cylinder under the XOY coordinate; calc K denotes: the slope of a straight line of the large arm cylinder under the XOY coordinate; a, B, C, D, E, F represent: static model coefficients; alpha represents: a large arm angle; beta represents: angle of the bucket rod.
It should be noted that, the calibration conditions of the dynamic weighing model are consistent with those of the static weighing model, and the specific calibration steps are as follows: the angle of the large arm is 17 degrees plus or minus 0.2 degrees, the angle of the bucket rod is minus 104 degrees plus or minus 0.2 degrees, and the bucket cylinder is retracted to the longest; and operating the large arm lifting handle to pull down to the bottom, and lifting the large arm to the bottom to be in an ending posture. It should be noted that, the bottom represents the maximum angle or the maximum limit, that is, the large arm lifting handle is pulled down to the maximum angle or the maximum limit, and the large arm is lifted to the maximum angle or the maximum limit.
In some alternative implementations of this embodiment, the boom down is performed in the same gear, returning to the boom initial position 17 °; setting the gear as 2 gears, and repeating the operation until the gear reaches 10 gears; and (3) storing data and carrying out nonlinear regression on the data to the formula A, cos alpha-B, sin alpha+C, cos beta-D, sin beta+E, cos beta-F, sin beta, so as to identify model coefficients fk and fv.
Specifically, the hydraulic cylinder resultant force is: f Closing device ＝Pnrod*A2-Prod*A1; wherein P nrod represents: variable amplitude cylinder rodless cavity pressure (Pa); p rod represents: the amplitude variation oil cylinder has rod cavity pressure (Pa); a 2 represents: the effective area of the rodless cavity of the amplitude variation oil cylinder; a 1 represents: the amplitude variation oil cylinder has a rod cavity effective area.
Specifically, the load weight calculation model in the excavator action process is as follows:
In the above formula: l radius represents: bucket load center of gravity is on the abscissa under the XOY coordinate system; p nrod represents: the pressure of the rodless cavity of the amplitude variable oil cylinder; a 2 represents: the effective area of the rodless cavity of the amplitude variation oil cylinder; p rod represents: the amplitude variation oil cylinder has rod cavity pressure; a 1 represents: the effective area of the rod cavity of the amplitude variation oil cylinder; f k denotes: static friction force of the oil cylinder; f v denotes: the viscosity friction coefficient of the oil cylinder; v represents: linear velocity of the amplitude variation cylinder; calc B denotes: the straight line intercept of the large arm oil cylinder under the XOY coordinate; calc K denotes: the slope of a straight line of the large arm cylinder under the XOY coordinate; a, B, C, D, E, F represent: static model coefficients; alpha represents: a large arm angle; beta represents: angle of the bucket rod.
Also to be described is: judging whether the gesture meets the loading weighing condition, and judging the opening degree of a large arm handle after the gesture is met, wherein the optimal weighing range is a bucket rod [ -120 degrees and-70 degrees ]; bucket [ -180 °, -150 ° ] and [0 °,10 ° ], large arm range [10 °,40 ° ]. If the condition is met, a stable pressure identification module can be started, and then real-time data of filtering resultant force of the large arm oil cylinder is read, wherein the data length is 30 (sliding reading); and calculating the slope of the resultant force curve of the oil cylinder after reading, selecting points as a plurality of groups of head and tail data, and finally screening the pressure stabilizing section data through a slope threshold value. In the present application, as one way that this embodiment can be implemented, the judgment condition is that the slope K is larger than 0, if K > 0, the stable pressure flag bit is identified, and the effective load average mass can be calculated at this time, and the data length is 30.
In some optional implementations of this embodiment, when determining whether the attitude meets a loading weighing condition, if the condition is met, the excavator must be operated within the attitude limit, i.e., a specific attitude; the optimal weighing range is the bucket rod [ -120 DEG, -70 DEG ]; bucket [ -180 °, -150 ° ] and [0 °,10 ° ], large arm range [10 °,40 ° ].
In some alternative implementations of this embodiment, the pressure recognition module may use a pressure sensor, but it should be noted that, here, the pressure input is an original parameter, the pressure is fluctuating, and the output or input of the pressure stabilizing section is implemented through a conversion processing display of the pressure sensor and the connection with an external existing control unit.
Therefore, the principle of the excavator dynamic weighing calculation method of the invention is as follows: the geometrical information of the load position and the pressure of the hydraulic cylinder are obtained by utilizing the angle and the pressure sensor, an equation is established by a moment balance principle, and the weight of the load is calculated, so that the load is dynamically weighed under each normal working period; the known input comprises structural parameter input, sensor input such as angle, pressure and the like, no-load moment, an oil cylinder arm and oil cylinder force are calculated, parameters are identified through static coefficient calibration and dynamic coefficient calibration, and finally weight is solved through actual moment, no-load moment and amplitude. Specifically, two models, namely a static weighing model and a dynamic weighing model, are included in the present invention; the static balance equation is established by the hinge point of the large arm body through the parameter input of the sensor, the static model coefficient is identified through the nonlinear regression of the data calibration on the static model, and the influence of the gravity center change of the tool on the weighing precision is directly avoided; on the basis of realizing a static model, the influence caused by parameters such as acceleration speed, moment of inertia and the like in the dynamic loading process is greatly reduced on the basis of coefficient regression of a dynamic model; in the specific loading attitude range process of the excavator, the stable area of the large arm oil cylinder is automatically identified, and the weighing of the load of the excavator is dynamically realized under each stable working period; the known sensor input and model calibration nonlinear regression can obtain load quality.
It should be noted that, the automatic identification of the stable region of the boom cylinder realizes the dynamic weighing of the load under each stable working period, i.e. the pressure identification module, such as the pressure sensor, identifies the stable region of the pressure.
In summary, the excavator dynamic weighing calculation method comprises the steps of including static model coefficients A, B, C, D, E and F; and fk and fv, can avoid the influence of the change of parameters such as the gravity center, speed, and the like when the excavator is weighed, and realize the effect of the change of parameters such as-120 degrees and-70 degrees of the bucket rod; the shovel is dynamically weighed in a large arm range [10 DEG, 40 DEG ] under the specific gesture, and the symmetrical heavy influencing factors in the static model are secondarily compensated by the dynamic model, so that the weighing measurement precision is greatly improved.
In addition, the invention also provides a dynamic weighing and calculating system of the excavator, which comprises the following components:
The static weighing model building module is used for obtaining the body excavation parameters of the excavator and building a static weighing model of the excavator when the excavator is in idle load; the identification model coefficient acquisition module is used for carrying out nonlinear regression on the static weighing model of the excavator in a data calibration mode to obtain an identification model coefficient; the dynamic weighing model building module is used for obtaining dynamic excavating parameters of the excavator and building a dynamic weighing model of the excavator; and the load weight calculation module is used for calculating the load weight in the action process of the excavator according to the established static weighing model, the identification model coefficient and the dynamic weighing model of the excavator.
According to the system disclosed by the invention, when the dynamic weighing calculation of the excavator is carried out, the influence of the gravity center, the speed and other parameter changes can be avoided when the excavator is dynamically weighed through the calculation among the system modules, so that the dynamic weighing of the excavator under a specific gesture is realized, and the weighing measurement precision is greatly improved.
It should be noted that in this document, relational terms such as "first" and "second" and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. In this context, "front", "rear", "left", "right", "upper" and "lower" are referred to with respect to the placement state shown in the drawings.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting thereof; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (9)
1. The dynamic weighing calculation method for the excavator is characterized by comprising the following steps of:
Acquiring the body excavation parameters of the excavator, and establishing a static weighing model of the excavator when the excavator is in idle load;
Nonlinear regression is carried out on a static weighing model of the excavator in a data calibration mode, so that an identification model coefficient is obtained;
acquiring dynamic excavation parameters of the excavator, and establishing a dynamic weighing model of the excavator;
and calculating the load weight of the excavator in the action process according to the established static weighing model, identification model coefficient and dynamic weighing model of the excavator.
2. The method of claim 1, wherein the body parameters include: boom angle α, stick angle β, and bucket angle γ.
3. The method for calculating the dynamic weighing of the excavator according to claim 1, wherein when the static weighing model and the dynamic weighing model are established, a hinge point of the large arm and the vehicle body is taken as an origin O of an absolute coordinate system, the right front is a positive direction of a horizontal axis X, and the right top is a positive direction of a longitudinal axis Y, and a two-dimensional coordinate system is established, wherein the static weighing model when the excavator is unloaded is as follows:
MEmpty＝(W1*x1+W2*G+W3*G)*cosα-(W1*y1)*sinα+(W2*x2+W3*I)*cosβ-(W2*y2)*sinβ+(W3*x3)*cosβ-(W3*y3)*sinβ
Wherein W 1 represents the mass of the large arm of the excavator; w 2 represents the mass of the excavator bucket rod; w 3 represents the excavator bucket mass; i represents the distance from the hinge point of the head of the excavator bucket to the hinge point of the head of the big arm; g represents the distance from the hinge point of the head of the large arm of the excavator to the rear hinge point of the large arm; x 1,x2,x3 respectively represents the abscissa of the gravity center of the large arm, the bucket rod and the bucket; y 1,y2,y3 represents the ordinate of the center of gravity of the boom, stick, and bucket, respectively.
4. The method of claim 1, wherein the identification model coefficients include a, B, C, D, E, and F, and the identification model coefficients are static model coefficients, wherein:
A*＝W1*x1+W2*G+W3*G；
B*＝W1*y1；
C*＝W2*x2+W3*I；
D*＝W2*y2；
E*＝W3*x3；
F*＝Wa*y3；
In the above formula, W 1 represents the excavator boom mass; w 2 represents the mass of the excavator bucket rod; w a represents the excavator bucket mass; i represents the distance from the hinge point of the head of the excavator bucket to the hinge point of the head of the big arm; g represents the distance from the hinge point of the head of the large arm of the excavator to the rear hinge point of the large arm; x 1,x2,x3 respectively represents the abscissa of the gravity center of the large arm, the bucket rod and the bucket; y 1,y2,y3 represents the ordinate of the center of gravity of the boom, stick, and bucket, respectively.
5. The method for calculating the dynamic weighing of the excavator according to claim 1, wherein when data calibration is carried out, the excavator is set to be in a low gear or an initial gear, the excavator is started, and when the temperature of hydraulic oil reaches 45 ° -60 °, the bucket rod and the large arm are calibrated respectively, wherein the calibration conditions are as follows:
The angle of the big arm is adjusted to 26 degrees+/-0.2 degrees, the angle of the bucket rod is adjusted to-100 degrees+/-0.2 degrees, and the bucket cylinder is shortened to the shortest time;
The angle of the large arm is adjusted to 26 degrees+/-0.2 degrees, the bucket rod oil cylinder is contracted to the shortest, and the bucket oil cylinder extends to the longest;
the angle of the big arm is adjusted to 17 degrees+/-0.2 degrees, the angle of the bucket rod is-104 degrees+/-0.2 degrees, the bucket cylinder is contracted to the longest, and the big arm is lifted to the bottom.
6. The method of claim 1, wherein the dynamic excavating parameters of the excavator include a static friction coefficient of a hydraulic cylinder, a viscous friction coefficient, a hydraulic cylinder pressure, a hydraulic cylinder inclination angle, a hydraulic cylinder speed, and a hydraulic cylinder resultant force.
7. The method for calculating the dynamic weighing of the excavator according to claim 6, wherein the resultant force of the hydraulic cylinders is as follows: f Closing device ＝Pnrod*A2-Prod*A1; wherein P nrod represents: variable amplitude cylinder rodless cavity pressure (Pa); p rod represents: the amplitude variation oil cylinder has rod cavity pressure (Pa); a 2 represents: the effective area of the rodless cavity of the amplitude variation oil cylinder; a 1 represents: the amplitude variation oil cylinder has a rod cavity effective area.
8. The method for calculating the dynamic weighing of the excavator according to claim 1, wherein the load weight calculation model in the action process of the excavator is as follows:
wherein: l radius represents: bucket load center of gravity is on the abscissa under the XOY coordinate system; p nrod represents: the pressure of the rodless cavity of the amplitude variable oil cylinder; a 2 represents: the effective area of the rodless cavity of the amplitude variation oil cylinder; p rod represents: the amplitude variation oil cylinder has rod cavity pressure; a 1 represents: the effective area of the rod cavity of the amplitude variation oil cylinder; f k denotes: static friction force of the oil cylinder; f v denotes: the viscosity friction coefficient of the oil cylinder; v represents: linear velocity of the amplitude variation cylinder; calc B denotes: the straight line intercept of the large arm oil cylinder under the XOY coordinate; calc K denotes: the slope of a straight line of the large arm cylinder under the XOY coordinate; a, B, C, D, E, F represent: static model coefficients; alpha represents: a large arm angle; beta represents: angle of the bucket rod.
9. A excavator dynamic weighing computing system, comprising:
the static weighing model building module is used for obtaining the body excavation parameters of the excavator and building a static weighing model of the excavator when the excavator is in idle load;
The identification model coefficient acquisition module is used for carrying out nonlinear regression on the static weighing model of the excavator in a data calibration mode to obtain an identification model coefficient;
the dynamic weighing model building module is used for obtaining dynamic excavating parameters of the excavator and building a dynamic weighing model of the excavator;
and the load weight calculation module is used for calculating the load weight in the action process of the excavator according to the established static weighing model, the identification model coefficient and the dynamic weighing model of the excavator.
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