Excavator impact load calculation method and system

Abstract

The invention discloses an excavator impact load calculation method which comprises the following steps: firstly, collecting the displacement and pressure of an oil cylinder of a working device of an excavator in a dynamic state, calculating and testing the actually measured oil cylinder force at an impact moment, and establishing a theoretical dynamic mathematical model; according to the established theoretical dynamic mathematical model, motion coordinates of a twisting point and a bucket tooth are calculated, and according to the motion coordinates and the gravity load of the excavator in the motion process, the theoretical mathematical model oil cylinder force of the working device is calculated by inputting assumed bucket tooth stress data; and finally, comparing the oil cylinder force of the theoretical mathematical model with the actually measured oil cylinder force at the impact moment to obtain an accurate impact load. The invention further provides a system for calculating the impact load of the excavator. The problems that in the prior art, special equipment needs to be used for excavation impact load testing, and testing data are different are solved. The impact load can be extracted more accurately only by collecting the pressure and displacement of the oil cylinder and considering the inertial load in the movement process.

Description

Technical Field

[0001] The present invention belongs to the field of hydraulic excavators, and in particular relates to a method for calculating the impact load of an excavator. The present invention also provides a system for calculating the impact load of an excavator. Background Art

[0002] Hydraulic excavators are one of the most widely used equipment in earth-moving machinery. The working device is a key component of hydraulic excavators. During the working process of the excavator, fatigue failure of the working device is a key factor restricting the improvement of the excavator quality, and the impact condition seriously affects the fatigue life of the working device. Therefore, it is particularly important to study the impact load of the excavator.

[0003] The Chinese invention patent (CN105067172A) discloses a force test device and test method for an excavator bucket. By improving the structure at the hinge point between the bucket and the dipper arm, a right hinge sensor and a left hinge sensor are set, and the right hinge sensor and the left hinge sensor are provided with a number of resistance strain gauges for measuring the lateral force Fa on the pin at the O axis, and the forces Fx and Fy on the pin at the O axis in the Ox plane and the Oy plane; the O axis lateral force and the forces on the Ox plane and the Oy plane on the bucket can be simply measured. The test results can be used as the original data of the load on the bucket during the development of the excavator, which is of great significance to improving the quality of the excavator and has high test accuracy. This method is applicable to all hydraulic excavators and loaders. The test device of this method is complex and the production cost is high, and it cannot be applied to the test of every model.

[0004] The Chinese invention patent (CN118228402A) discloses a composite excavation force analysis method, which is based on the actual excavation trajectory and oil pressure data, and selects two cylinders to actively calculate the composite excavation force. Compared with the traditional theoretical excavation force analysis method of a single cylinder, it is more in line with the actual excavation law of the excavator, solves the problem of mismatch between the traditional theoretical excavation force analysis method and the actual load, and can more accurately analyze the theoretical composite excavation force of the excavator, thereby improving the accuracy of the theoretical analysis in the design stage; for the processing method of the singular area of ​​the excavator's composite excavation action, the problem of distortion in the solution of the composite excavation force near the singular point is solved, and the arm cylinder and the bucket cylinder are used as active working cylinders at the same time, without limiting the oil pressure coupling of the two active cylinders, and a direction-determined composite excavation force calculation method is established, which can more comprehensively analyze the size and direction of all possible composite excavation forces under a certain excavation posture and within the oil pressure range that the active cylinder can provide; compared with the existing theoretical excavation force analysis method, this method can more truly and accurately reflect the excavation capacity of the excavator, which is conducive to theoretical analysis in the product design stage. This method is a theoretical analysis in the product design stage and does not take into account the impact of the impact load during the actual operation of the excavator. Therefore, there will be differences in the data of the digging force analysis. Summary of the invention

[0005] In order to overcome the defects in the prior art that special equipment is needed to test the excavation impact load and there are differences in the test data, the present invention provides an excavator impact load calculation method that only needs to collect the cylinder pressure and displacement, considers the gravity load of the working device during the movement, and uses the moment balance method, test data and mathematical model to more accurately extract the impact load of the working device.

[0006] The technical solution adopted by the present invention to achieve the above-mentioned purpose is: A method for calculating the impact load of an excavator comprises the following steps: firstly collecting the displacement and pressure of the oil cylinder of a working device of the excavator under dynamic conditions, calculating the oil cylinder force actually measured at the time of impact test, and establishing a theoretical dynamic mathematical model; then calculating the hinge point and the motion coordinates of bucket teeth according to the established theoretical dynamic mathematical model, and calculating the theoretical mathematical model oil cylinder force of the working device according to the motion coordinates and the gravity load of the excavator during the motion process by inputting the assumed bucket tooth force data; finally, comparing the theoretical mathematical model oil cylinder force with the actually measured oil cylinder force at the time of impact, and obtaining an accurate impact load.

[0007] Furthermore, the step of calculating the hinge point and bucket tooth motion coordinates by the established dynamic mathematical model is: the model and working device size of the excavator are known, and AM points are set on the working device of the excavator, and the displacement angle of the working device is calculated according to the collected oil cylinder displacement of the working device, and the coordinate position of each hinge point of AM is calculated by the displacement angle; The working device includes a boom, an arm, and a bucket, and the positioning angles include a displacement angle of the boom relative to the platform, a displacement angle of the arm relative to the boom, and a displacement angle of the bucket relative to the arm; The calculation obtains the displacement angle a of the movable arm relative to the platform: a=arccos((AB^2+AC^2-BC^2) / (2*AB*AC))-∠EAC-∠ABy-; Where: BC represents the displacement of the boom cylinder; The calculation results in the displacement angle b of the bucket arm relative to the boom: b=-(Π-(2*Π-∠AED-∠FEK-arccos((ED^2+EF^2-DF^2) / (2*DE*EF)))); Where: DF represents the displacement of the boom cylinder; The calculation results in the displacement angle c of the bucket relative to the dipper arm: ∠GHJ=arccos((GH^2+HJ^2-GJ^2) / (2*GH*HJ)); ∠JGH=arccos((GH^2+GJ^2-HJ^2) / (2*GH*GJ)); ∠GJH=Π-∠JGH-∠GHJ; ∠JHK=∠GHK-∠GHJ; JK=(HJ^2+HK^2-2*HJ*HK*cos(∠JHK))^0.5; ∠JKL=arccos((JK^2+KL^2-JL^2) / (2*JK*KL)); ∠JKH=arccos((HK^2+JK^2-HJ^2) / (2*JK*HK)); c=-(Π-(2*Π-∠EKH-∠JKL-∠MKL-∠JKH)); Where: GJ represents the displacement of the bucket cylinder; The calculation results in the coordinate positions of each AM node: Ya=known parameters; Za = known parameters; Yc=AC*cos(a+∠EAC); Zc=AC*sin(a+∠EAC); Yg1=AG1*cos(a+∠EAG1); Zg1=AG1*sin(a+∠EAG1); Ye=AE*cos(a); Ze=AE*sin(a); Yd=AD*cos(a+∠EAD); Zd=AD*sin(a+∠EAD); Yf=AE*cos(a)+EF*cos(∠FEK+a+b); Zf=AE*sin(a)+EF*sin(∠FEK+a+b); Yg=AE*cos(a)+EG*cos(∠GEK+a+b); Zg=AE*sin(a)+EG*sin(∠GEK+a+b); Yg2=AE*cos(a)+BG2*cos(∠KEG2+a+b); Zg2=AE*sin(a)+BG2*sin(∠KEG2+a+b); Yh=AE*cos(a)+EH*cos(∠HEK+a+b); Zh=AE*sin(a)+EH*sin(∠HEK+a+b); Yk=AE*cos(a)+EK*cos(a+b); Zk=AE*sin(a)+EK*sin(a+b); Ym=EK*cos(a+b)+AE*cos(a)+KM*cos(a+b+c); Zm=EK*sin(a+b)+AE*sin(a)+KM*sin(a+b+c); Yl=EK*cos(a+b)+AE*cos(a)+KL*cos(∠MKL+a+b+c); Zl=EK*sin(a+b)+AE*sin(a)+KL*sin(∠MKL+a+b+c); Yg3=EK*cos(a+b)+AE*cos(a)+KG3*cos(∠MKG3+a+b+c); Zg3=EK*sin(a+b)+AE*sin(a)+KG3*sin(∠MKG3+a+b+c); Yj=EK*cos(a+b)+JK*cos(∠JKL+∠MKL+a+b+c)+AB*cos(a); Zj=EK*sin(a+b)+JK*sin(∠JKL+∠MKL+a+b+c)+AB*sin(a); Where: Y*, Z* represent the horizontal and vertical coordinates of each hinge point in the YOZ coordinate system; given the model and working device dimensions of the excavator, a two-dimensional coordinate system is established with the intersection of the rotation center and the horizontal line as the origin o of the absolute coordinate system, the positive direction of the horizontal axis y in front and the positive direction of the vertical axis z above. A indicates the hinge point of the rear support of the boom, B indicates the hinge point of the large cavity of the boom cylinder, C indicates the hinge point of the middle support of the boom, i.e. the small cavity of the boom cylinder, D indicates the hinge point of the large cavity of the arm cylinder, E indicates the hinge point of the front support of the boom, i.e. the hinge point of the rear support of the arm, F indicates the hinge point of the small cavity of the arm cylinder, G indicates the hinge point of the large cavity of the bucket cylinder, J indicates the hinge point of the small cavity of the bucket cylinder, H indicates the hinge point of the middle support of the arm, K indicates the hinge point of the front support of the arm, i.e. the hinge point of the rear ear plate of the bucket, L indicates the hinge point of the front ear plate of the bucket, M indicates the bucket tooth point, g1 indicates the center of gravity of the boom, g2 indicates the center of gravity of the arm, g3 indicates the center of gravity of the bucket, a indicates the movement angle of the boom relative to the slewing platform, b indicates the movement angle of the arm relative to the boom, and c indicates the movement angle of the bucket relative to the arm.

[0008] Further, the step of calculating the cylinder pressure by inputting the assumed bucket tooth force data through the motion coordinates and the gravity load of the excavator during the motion is: according to the coordinate positions of each hinge point of AM, the boom, the dipper arm, and the bucket use the moment balance method to calculate the moment balance of the three points A, E, and K respectively, and obtain the boom, dipper arm, and bucket cylinder forces; The bucket seeks moment balance at point K, and the bucket cylinder force is obtained: f5=arctan(Zj-Zl,Yj-Yl); Fly=-Fmy*(Zk-Zm)+Fmz*(Yk-Ym)+Fg3z*(YkYg3)) / ((Zk-Zl)-(sin(f5) / cos(f5)*(Yk-Yl)); F4=Fly / cos(f5); Fbucket=-F4*sin(∠LJH) / sin(∠GJH); Where: Fg3z represents bucket gravity, Fmy and Fmz represent bucket tooth tip force values, which need to be input by yourself and calibrated by the measured cylinder pressure; The arm moment balance at point E can be obtained by: Fky=-Fly-Fmy; Fkz=-Flz-Fg3z-Fkz; f3=arctan(Zg-Zj,Yg-Yj); Fgy=Fbucket*cos(f3); Fgz=Fbucket*sin(f3); f4=arctan(Zh-Zj,Yh-Yj); Fhy=-(Fbucket*sin(Π-∠GJH-∠LJH) / sin(∠LJH))*cos(f4); Fhz=-(Fbucket*sin(Π-∠GJH-∠LJH) / sin(∠LJH))*sin(f4); f2=arctan(Zd-Zf,Yd-Yf); Ffy=-(-Fky*(Ze-Zk)+Fhy*(Ze-Zh)+Fgy*(Ze-Zg)+Fkz*(Ye-Yk)-Fhz*(Ye-Yh)-Fg2z*(Ye-Yg2)-Fgz*(Ye-Yg)) / (-(tan(f2)*(Ye-Yf))+(Ze-Zf)); Ffz=Ffy*tan(f2); Fdy=-Ffy; Fdz=-Ffz; Farm=sqrt(Ffy^2+Ffz^2); Where: Fg2z represents the weight of the arm; The moment balance of the boom about point A is obtained, and the boom cylinder force is obtained: Fey=Fky-Fhy-Fgy-Ffy; Fez=Fkz-Fhz-Fgz-Fg2z-Ffz; f1=a+EAC+ACB; Fcy=-(-Fey*(Za-Ze)+Fdy*(Za-Zd)+Fez*(Ya-Ye)-Fdz*(Ya-Yd)-Fg1z*(Ya-Yg1)) / (-(tan(f1)*(Ya-Yc))+(Za-Zc)); Fcz=Fcy*tan(f1); Fboom=Fcy / cos(f1); Where: Fg1z represents the boom gravity.

[0009] Furthermore, the measured oil cylinder pressure at the impact moment is calculated based on the collected oil cylinder pressure, and the specific calculation steps are as follows: Fboom measurement = number of cylinders*(pb1*sb1-pb2*(sb1-sb2))*10^6; Farm measurement = number of oil cylinders*(pa1*sa1-pa2*(sa1-sa2))*10^6; Fbucket measurement = number of oil cylinders * (pc1*sc1-pc2*(sc1-sc2))*10^6; In the formula: pb1 represents the large-cavity cylinder pressure of the boom, pb2 represents the small-cavity cylinder pressure of the boom, sb1 represents the large-cavity cross-sectional area of ​​the boom, sb2 represents the small-cavity cross-sectional area of ​​the boom; pa1 represents the large-cavity cylinder pressure of the arm, pa2 represents the small-cavity cylinder pressure of the arm, sa1 represents the large-cavity cross-sectional area of ​​the arm, sa2 represents the small-cavity cross-sectional area of ​​the boom; pc1 represents the large-cavity cylinder pressure of the bucket, pc2 represents the small-cavity cylinder pressure of the bucket, sc1 represents the large-cavity cross-sectional area of ​​the bucket, and sc2 represents the small-cavity cross-sectional area of ​​the bucket.

[0010] Preferably, the step of comparing the theoretical mathematical model cylinder force with the actually measured cylinder force at the impact moment to obtain the accurate impact load is: (theoretical mathematical model cylinder force - actually measured cylinder force at the impact moment) / If the value of the theoretical mathematical model cylinder force is less than 5%, the accurate impact load is the theoretical mathematical model cylinder force; otherwise, it is necessary to re-enter Fmy, Fmz and recalculate until the three cylinder forces match the sizes of the three tested cylinder forces.

[0011] Preferably, the cylinder pressure and displacement are acquired by using a cylinder pressure sensor and a wire displacement sensor; the movement of the excavator boom, arm and bucket is compounded with the rotation of the rear support.

[0012] The present invention also provides an excavator impact load calculation system, comprising: Dynamic mathematical model building module, collects the cylinder displacement and pressure of the working device under the dynamic state of the excavator, and builds a theoretical dynamic mathematical model; The module for acquiring the measured cylinder pressure at the impact moment calculates the measured cylinder force at the impact moment based on the collected cylinder force of the working device under the dynamic state of the excavator; The force analysis module calculates the hinge point and bucket tooth motion coordinates through the established dynamic mathematical model. The theoretical mathematical model cylinder force of the working device is calculated through the motion coordinates and the gravity load of the excavator during the movement. The impact load calculation module compares the theoretical mathematical model cylinder force with the measured cylinder force at the impact moment to obtain the accurate impact load.

[0013] Furthermore, the specific steps of the force analysis module are as follows: the model and size of the working device of the excavator are known, and an AM point is set on the working device of the excavator. The displacement angle of the working device is calculated according to the collected cylinder displacement of the working device, and the coordinate position of each AM hinge point is calculated by the displacement angle. According to the coordinate position, the load calculation system calculates the moment balance for the three points A, E, and K respectively according to the moment balance method, and the theoretical mathematical model cylinder force of the working device can be calculated.

[0014] Furthermore, the steps of the cylinder force calculation module are: (theoretical mathematical model cylinder force-actually measured cylinder force at the impact moment) / If the value of the theoretical mathematical model cylinder force is less than 5%, the accurate impact load is the theoretical mathematical model cylinder force; otherwise, Fmy and Fmz need to be re-entered and recalculated until the three cylinder forces match the sizes of the three tested cylinder forces.

[0015] Preferably, the working device includes a boom, a bucket and an arm, and cylinder pressure sensors and wire displacement sensors are respectively provided on the cylinders of the boom, the bucket and the arm.

[0016] The present invention only needs to collect the dynamic cylinder pressure and displacement of the excavator, establish a dynamic mathematical model, and calculate the hinge point and bucket tooth motion coordinates. According to the obtained motion coordinates, the gravity load of the working device during the movement is considered, and the impact load of the working device is more accurately extracted through the moment balance method, test data and mathematical model. The impact load calculation method adopts the method of calibrating the cylinder force by testing and mathematical calculation, the purpose of which is to calculate the load size at the impact moment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below in conjunction with the accompanying drawings, in which: Figure 1 It is a flow chart of the present invention; Figure 2 This is a schematic diagram of the working state structure of the excavator and working device. DETAILED DESCRIPTION

[0018] Example 1

[0019] like Figures 1 to 2 As shown, the excavator impact load calculation method of this embodiment includes the following steps: The excavator impact load calculation method includes the following steps: first collect the cylinder displacement and pressure of the working device of the excavator under dynamic conditions, calculate the actual cylinder force at the test impact moment, and establish a theoretical dynamic mathematical model; then calculate the hinge point and bucket tooth motion coordinates according to the established theoretical dynamic mathematical model, and calculate the theoretical mathematical model cylinder force of the working device according to the motion coordinates and the gravity load of the excavator during the movement by inputting the assumed bucket tooth force data; finally, compare the theoretical mathematical model cylinder force with the actual measured cylinder force at the impact moment to obtain an accurate impact load.

[0020] Furthermore, the step of calculating the hinge point and bucket tooth motion coordinates by the established dynamic mathematical model is: the model and working device size of the excavator are known, and AM points are set on the working device of the excavator, and the displacement angle of the working device is calculated according to the collected oil cylinder displacement of the working device, and the coordinate position of each hinge point of AM is calculated by the displacement angle; The working device includes a boom, an arm, and a bucket, and the positioning angles include a displacement angle of the boom relative to the platform, a displacement angle of the arm relative to the boom, and a displacement angle of the bucket relative to the arm; The calculation obtains the displacement angle a of the movable arm relative to the platform: a=arccos((AB^2+AC^2-BC^2) / (2*AB*AC))-∠EAC-∠ABy-; Where: BC represents the displacement of the boom cylinder; The calculation results in the displacement angle b of the bucket arm relative to the boom: b=-(Π-(2*Π-∠AED-∠FEK-arccos((ED^2+EF^2-DF^2) / (2*DE*EF)))); Where: DF represents the displacement of the boom cylinder; The calculation results in the displacement angle c of the bucket relative to the dipper arm: ∠GHJ=arccos((GH^2+HJ^2-GJ^2) / (2*GH*HJ)); ∠JGH=arccos((GH^2+GJ^2-HJ^2) / (2*GH*GJ)); ∠GJH=Π-∠JGH-∠GHJ; ∠JHK=∠GHK-∠GHJ; JK=(HJ^2+HK^2-2*HJ*HK*cos(∠JHK))^0.5; ∠JKL=arccos((JK^2+KL^2-JL^2) / (2*JK*KL)); ∠JKH=arccos((HK^2+JK^2-HJ^2) / (2*JK*HK)); c=-(Π-(2*Π-∠EKH-∠JKL-∠MKL-∠JKH)); Where: GJ represents the displacement of the bucket cylinder; The calculation results in the coordinate positions of each AM node: Ya=known parameters; Za = known parameters; Yc=AC*cos(a+∠EAC); Zc=AC*sin(a+∠EAC); Yg1=AG1*cos(a+∠EAG1); Zg1=AG1*sin(a+∠EAG1); Ye=AE*cos(a); Ze=AE*sin(a); Yd=AD*cos(a+∠EAD); Zd=AD*sin(a+∠EAD); Yf=AE*cos(a)+EF*cos(∠FEK+a+b); Zf=AE*sin(a)+EF*sin(∠FEK+a+b); Yg=AE*cos(a)+EG*cos(∠GEK+a+b); Zg=AE*sin(a)+EG*sin(∠GEK+a+b); Yg2=AE*cos(a)+BG2*cos(∠KEG2+a+b); Zg2=AE*sin(a)+BG2*sin(∠KEG2+a+b); Yh=AE*cos(a)+EH*cos(∠HEK+a+b); Zh=AE*sin(a)+EH*sin(∠HEK+a+b); Yk=AE*cos(a)+EK*cos(a+b); Zk=AE*sin(a)+EK*sin(a+b); Ym=EK*cos(a+b)+AE*cos(a)+KM*cos(a+b+c); Zm=EK*sin(a+b)+AE*sin(a)+KM*sin(a+b+c); Yl=EK*cos(a+b)+AE*cos(a)+KL*cos(∠MKL+a+b+c); Zl=EK*sin(a+b)+AE*sin(a)+KL*sin(∠MKL+a+b+c); Yg3=EK*cos(a+b)+AE*cos(a)+KG3*cos(∠MKG3+a+b+c); Zg3=EK*sin(a+b)+AE*sin(a)+KG3*sin(∠MKG3+a+b+c); Yj=EK*cos(a+b)+JK*cos(∠JKL+∠MKL+a+b+c)+AB*cos(a); Zj=EK*sin(a+b)+JK*sin(∠JKL+∠MKL+a+b+c)+AB*sin(a); Where: Y*, Z* represent the horizontal and vertical coordinates of each hinge point in the YOZ coordinate system; given the model and working device dimensions of the excavator, a two-dimensional coordinate system is established with the intersection of the rotation center and the horizontal line as the origin o of the absolute coordinate system, the positive direction of the horizontal axis y in front and the positive direction of the vertical axis z above. A indicates the hinge point of the rear support of the boom, B indicates the hinge point of the large cavity of the boom cylinder, C indicates the hinge point of the middle support of the boom, i.e. the small cavity of the boom cylinder, D indicates the hinge point of the large cavity of the arm cylinder, E indicates the hinge point of the front support of the boom, i.e. the hinge point of the rear support of the arm, F indicates the hinge point of the small cavity of the arm cylinder, G indicates the hinge point of the large cavity of the bucket cylinder, J indicates the hinge point of the small cavity of the bucket cylinder, H indicates the hinge point of the middle support of the arm, K indicates the hinge point of the front support of the arm, i.e. the hinge point of the rear ear plate of the bucket, L indicates the hinge point of the front ear plate of the bucket, M indicates the bucket tooth point, g1 indicates the center of gravity of the boom, g2 indicates the center of gravity of the arm, g3 indicates the center of gravity of the bucket, a indicates the movement angle of the boom relative to the slewing platform, b indicates the movement angle of the arm relative to the boom, and c indicates the movement angle of the bucket relative to the arm.

[0021] Further, the step of calculating the cylinder pressure by inputting the assumed bucket tooth force data through the motion coordinates and the gravity load of the excavator during the motion is: according to the coordinate positions of each hinge point of AM, the boom, the dipper arm, and the bucket use the moment balance method to calculate the moment balance of the three points A, E, and K respectively, and obtain the boom, dipper arm, and bucket cylinder forces; The bucket seeks moment balance at point K, and the bucket cylinder force is obtained: f5=arctan(Zj-Zl,Yj-Yl); Fly=-Fmy*(Zk-Zm)+Fmz*(Yk-Ym)+Fg3z*(YkYg3)) / ((Zk-Zl)-(sin(f5) / cos(f5)*(Yk-Yl)); F4=Fly / cos(f5); Fbucket=-F4*sin(∠LJH) / sin(∠GJH); Where: Fg3z represents bucket gravity, Fmy and Fmz represent bucket tooth tip force values, which need to be input by yourself and calibrated by the measured cylinder pressure; The arm moment balance at point E can be obtained by: Fky=-Fly-Fmy; Fkz=-Flz-Fg3z-Fkz; f3=arctan(Zg-Zj,Yg-Yj); Fgy=Fbucket*cos(f3); Fgz=Fbucket*sin(f3); f4=arctan(Zh-Zj,Yh-Yj); Fhy=-(Fbucket*sin(Π-∠GJH-∠LJH) / sin(∠LJH))*cos(f4); Fhz=-(Fbucket*sin(Π-∠GJH-∠LJH) / sin(∠LJH))*sin(f4); f2=arctan(Zd-Zf,Yd-Yf); Ffy=-(-Fky*(Ze-Zk)+Fhy*(Ze-Zh)+Fgy*(Ze-Zg)+Fkz*(Ye-Yk)-Fhz*(Ye-Yh)-Fg2z*(Ye-Yg2)-Fgz*(Ye-Yg)) / (-(tan(f2)*(Ye-Yf))+(Ze-Zf)); Ffz=Ffy*tan(f2); Fdy=-Ffy; Fdz=-Ffz; Farm=sqrt(Ffy^2+Ffz^2); Where: Fg2z represents the weight of the arm; The moment balance of the boom about point A is obtained, and the boom cylinder force is obtained: Fey=Fky-Fhy-Fgy-Ffy; Fez=Fkz-Fhz-Fgz-Fg2z-Ffz; f1=a+EAC+ACB; Fcy=-(-Fey*(Za-Ze)+Fdy*(Za-Zd)+Fez*(Ya-Ye)-Fdz*(Ya-Yd)-Fg1z*(Ya-Yg1)) / (-(tan(f1)*(Ya-Yc))+(Za-Zc)); Fcz=Fcy*tan(f1); Fboom=Fcy / cos(f1); Where: Fg1z represents the boom gravity.

[0022] Furthermore, the measured oil cylinder pressure at the impact moment is calculated based on the collected oil cylinder pressure, and the specific calculation steps are as follows: Fboom measurement = number of cylinders*(pb1*sb1-pb2*(sb1-sb2))*10^6; Farm measurement = number of oil cylinders*(pa1*sa1-pa2*(sa1-sa2))*10^6; Fbucket measurement = number of oil cylinders * (pc1*sc1-pc2*(sc1-sc2))*10^6; In the formula: pb1 represents the large-cavity cylinder pressure of the boom, pb2 represents the small-cavity cylinder pressure of the boom, sb1 represents the large-cavity cross-sectional area of ​​the boom, sb2 represents the small-cavity cross-sectional area of ​​the boom; pa1 represents the large-cavity cylinder pressure of the arm, pa2 represents the small-cavity cylinder pressure of the arm, sa1 represents the large-cavity cross-sectional area of ​​the arm, sa2 represents the small-cavity cross-sectional area of ​​the boom; pc1 represents the large-cavity cylinder pressure of the bucket, pc2 represents the small-cavity cylinder pressure of the bucket, sc1 represents the large-cavity cross-sectional area of ​​the bucket, and sc2 represents the small-cavity cross-sectional area of ​​the bucket.

[0023] Preferably, the step of comparing the theoretical mathematical model cylinder force with the actually measured cylinder force at the impact moment to obtain the accurate impact load is: (theoretical mathematical model cylinder force - actually measured cylinder force at the impact moment) / If the value of the theoretical mathematical model cylinder force is less than 5%, the accurate impact load is the theoretical mathematical model cylinder force; otherwise, it is necessary to re-enter Fmy, Fmz and recalculate until the three cylinder forces match the sizes of the three tested cylinder forces.

[0024] Preferably, the cylinder pressure and displacement are acquired by using a cylinder pressure sensor and a wire displacement sensor; the movement of the excavator boom, arm and bucket is compounded with the rotation of the rear support.

[0025] Example 2

[0026] like Figures 1 to 2 As shown, the excavator impact load calculation system of this embodiment includes: Dynamic mathematical model building module, collects the cylinder displacement and pressure of the working device under the dynamic state of the excavator, and builds a theoretical dynamic mathematical model; The module for acquiring the measured cylinder pressure at the impact moment calculates the measured cylinder force at the impact moment based on the collected cylinder force of the working device under the dynamic state of the excavator; The force analysis module calculates the hinge point and bucket tooth motion coordinates through the established dynamic mathematical model. The theoretical mathematical model cylinder force of the working device is calculated through the motion coordinates and the gravity load of the excavator during the movement. The impact load calculation module compares the theoretical mathematical model cylinder force with the measured cylinder force at the impact moment to obtain the accurate impact load.

[0027] Furthermore, the specific steps of the force analysis module are as follows: the model and size of the working device of the excavator are known, and an AM point is set on the working device of the excavator. The displacement angle of the working device is calculated according to the collected cylinder displacement of the working device. The coordinate position of each AM hinge point is calculated through the displacement angle. According to the coordinate position and the moment balance method, the moment balance is calculated for the three points A, E, and K respectively, and the theoretical mathematical model cylinder force of the working device can be calculated.

[0028] Furthermore, the steps of the cylinder force calculation module are: (theoretical mathematical model cylinder force-actually measured cylinder force at the impact moment) / If the value of the theoretical mathematical model cylinder force is less than 5%, the accurate impact load is the theoretical mathematical model cylinder force; otherwise, Fmy and Fmz need to be re-entered and recalculated until the three cylinder forces match the sizes of the three tested cylinder forces.

[0029] Preferably, the working device comprises a boom, a bucket and a dipper rod, and the oil cylinders of the boom, the bucket and the dipper rod are respectively provided with an oil cylinder pressure sensor and a pull-wire displacement sensor. The oil cylinder pressure sensor and the pull-wire displacement sensor are both universal models.

[0030] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for calculating the impact load of an excavator, characterized in that: The following steps are involved: First, the cylinder displacement and pressure of the working device of the excavator under dynamic conditions are collected, the measured cylinder force at the test impact moment is calculated, and a theoretical dynamic mathematical model is established; then, the hinge point and bucket tooth motion coordinates are calculated based on the established theoretical dynamic mathematical model, and the theoretical mathematical model cylinder force of the working device is calculated by inputting the assumed bucket tooth force data based on the motion coordinates and the gravity load of the excavator during movement; finally, the theoretical mathematical model cylinder force is compared with the measured cylinder force at the impact moment to obtain an accurate impact load.

2. The method for calculating the impact load of an excavator according to claim 1, characterized in that: The steps of calculating the hinge point and bucket tooth motion coordinates by the established dynamic mathematical model are: the model and size of the working device of the excavator are known, and the AM point position is set on the working device of the excavator, and the displacement angle of the working device is calculated according to the collected oil cylinder displacement of the working device, and the coordinate position of each hinge point of the AM is calculated by the displacement angle; The working device includes a boom, an arm, and a bucket, and the positioning angles include a displacement angle of the boom relative to the platform, a displacement angle of the arm relative to the boom, and a displacement angle of the bucket relative to the arm; The calculation obtains the displacement angle a of the movable arm relative to the platform: a=arccos((AB^2+AC^2-BC^2) / (2*AB*AC))-∠EAC-∠ABy-; Where: BC represents the displacement of the boom cylinder; The calculation results in the displacement angle b of the bucket arm relative to the boom: b=-(Π-(2*Π-∠AED-∠FEK-arccos((ED^2+EF^2-DF^2) / (2*DE*EF)))); Where: DF represents the displacement of the boom cylinder; The calculation obtains the displacement angle c of the bucket relative to the dipper arm; ∠GHJ=arccos((GH^2+HJ^2-GJ^2) / (2*GH*HJ)); ∠JGH=arccos((GH^2+GJ^2-HJ^2) / (2*GH*GJ)); ∠GJH=Π-∠JGH-∠GHJ; ∠JHK=∠GHK-∠GHJ; JK=(HJ^2+HK^2-2*HJ*HK*cos(∠JHK))^0.5; ∠JKL=arccos((JK^2+KL^2-JL^2) / (2*JK*KL)); ∠JKH=arccos((HK^2+JK^2-HJ^2) / (2*JK*HK)); c=-(Π-(2*Π-∠EKH-∠JKL-∠MKL-∠JKH)); Where: GJ represents the displacement of the bucket cylinder; The calculation results in the coordinate positions of each AM node: Ya = known parameters; Za = known parameters; Yc=AC*cos(a+∠EAC); Zc=AC*sin(a+∠EAC); Yg1=AG1*cos(a+∠EAG1); Zg1=AG1*sin(a+∠EAG1); Ye = AE * cos (a); Ze = AE*sin(a); Yd=AD*cos(a+∠EAD); Zd=AD*sin(a+∠EAD); Yf=AE*cos(a)+EF*cos(∠FEK+a+b); Zf=AE*sin(a)+EF*sin(∠FEK+a+b); Yg=AE*cos(a)+EG*cos(∠GEK+a+b); Zg=AE*sin(a)+EG*sin(∠GEK+a+b); Yg2=AE*cos(a)+BG2*cos(∠KEG2+a+b); Zg2=AE*sin(a)+BG2*sin(∠KEG2+a+b); Yh=AE*cos(a)+EH*cos(∠HEK+a+b); Zh=AE*sin(a)+EH*sin(∠HEK+a+b); Yk=AE*cos(a)+EK*cos(a+b); Zk=AE*sin(a)+EK*sin(a+b); Ym=EK*cos(a+b)+AE*cos(a)+KM*cos(a+b+c); Zm=EK*sin(a+b)+AE*sin(a)+KM*sin(a+b+c); Yl=EK*cos(a+b)+AE*cos(a)+KL*cos(∠MKL+a+b+c); Zl=EK*sin(a+b)+AE*sin(a)+KL*sin(∠MKL+a+b+c); Yg3=EK*cos(a+b)+AE*cos(a)+KG3*cos(∠MKG3+a+b+c); Zg3=EK*sin(a+b)+AE*sin(a)+KG3*sin(∠MKG3+a+b+c); Yj=EK*cos(a+b)+JK*cos(∠JKL+∠MKL+a+b+c)+AB*cos(a); Zj=EK*sin(a+b)+JK*sin(∠JKL+∠MKL+a+b+c)+AB*sin(a); Where: Y*, Z* represent the horizontal and vertical coordinates of each hinge point in the YOZ coordinate system; given the model and working device dimensions of the excavator, a two-dimensional coordinate system is established with the intersection of the rotation center and the horizontal line as the origin o of the absolute coordinate system, the positive direction of the horizontal axis y in front and the positive direction of the vertical axis z above. A indicates the hinge point of the rear support of the boom, B indicates the hinge point of the large cavity of the boom cylinder, C indicates the hinge point of the middle support of the boom, i.e. the small cavity of the boom cylinder, D indicates the hinge point of the large cavity of the arm cylinder, E indicates the hinge point of the front support of the boom, i.e. the hinge point of the rear support of the arm, F indicates the hinge point of the small cavity of the arm cylinder, G indicates the hinge point of the large cavity of the bucket cylinder, J indicates the hinge point of the small cavity of the bucket cylinder, H indicates the hinge point of the middle support of the arm, K indicates the hinge point of the front support of the arm, i.e. the hinge point of the rear ear plate of the bucket, L indicates the hinge point of the front ear plate of the bucket, M indicates the bucket tooth point, g1 indicates the center of gravity of the boom, g2 indicates the center of gravity of the arm, g3 indicates the center of gravity of the bucket, a indicates the movement angle of the boom relative to the slewing platform, b indicates the movement angle of the arm relative to the boom, and c indicates the movement angle of the bucket relative to the arm.

3. The method for calculating the impact load of an excavator according to claim 2, characterized in that: The steps of calculating the cylinder pressure by inputting the assumed bucket tooth force data through the motion coordinates and the gravity load of the excavator during the motion process are as follows: according to the coordinate positions of each hinge point of AM, the boom, dipper arm and bucket use the moment balance method to calculate the moment balance of the three points A, E and K respectively, and obtain the boom, dipper arm and bucket cylinder forces; The bucket seeks moment balance at point K, and the bucket cylinder force is obtained: f5=arctan(Zj-Zl,Yj-Yl); Fly=-Fmy*(Zk-Zm)+Fmz*(Yk-Ym)+Fg3z*(YkYg3)) / ((Zk-Zl)-(sin(f5) / cos(f5)*(Yk-Yl)); F4=Fly / cos(f5); Fbucket=-F4*sin(∠LJH) / sin(∠GJH); Where: Fg3z represents bucket gravity, Fmy and Fmz represent bucket tooth tip force values, which need to be input by yourself and calibrated by the measured cylinder pressure; The arm moment balance at point E can be obtained by: Fky=-Fly-Fmy; Fkz=-Flz-Fg3z-Fkz; f3=arctan(Zg-Zj,Yg-Yj); Fgy=Fbucket*cos(f3); Fgz=Fbucket*sin(f3); f4=arctan(Zh-Zj,Yh-Yj); Fhy=-(Fbucket*sin(Π-∠GJH-∠LJH) / sin(∠LJH))*cos(f4); Fhz=-(Fbucket*sin(Π-∠GJH-∠LJH) / sin(∠LJH))*sin(f4); f2=arctan(Zd-Zf,Yd-Yf); Ffy=-(-Fky*(Ze-Zk)+Fhy*(Ze-Zh)+Fgy*(Ze-Zg)+Fkz*(Ye-Yk)-Fhz*(Ye-Yh)-Fg2z*(Ye-Yg2)-Fgz*(Ye-Yg)) / (-(tan(f2)*(Ye-Yf))+(Ze-Zf)); Ffz=Ffy*tan(f2); Fdy=-Ffy; Fdz=-Ffz; Farm = sqrt(Ffy^2+Ffz^2); Where: Fg2z represents the weight of the arm; The moment balance of the boom about point A is obtained, and the boom cylinder force is obtained: Fey=Fky-Fhy-Fgy-Ffy; Fez=Fkz-Fhz-Fgz-Fg2z-Ffz; f1=a+∠EAC+∠ACB; Fcy=-(-Fey*(Za-Ze)+Fdy*(Za-Zd)+Fez*(Ya-Ye)-Fdz*(Ya-Yd)-Fg1z*(Ya-Yg1)) / (-(tan(f1)*(Ya-Yc))+(Za-Zc)); Fcz=Fcy*tan(f1); Fboom = Fcy / cos(f1); Where: Fg1z represents the boom gravity.

4. The method for calculating the impact load of an excavator according to claim 1, characterized in that: The measured oil cylinder pressure at the impact moment is calculated based on the collected oil cylinder pressure. The specific calculation steps are as follows: Fboom measurement = number of cylinders*(pb1*sb1-pb2*(sb1-sb2))*10^6; Farm measurement = number of oil cylinders*(pa1*sa1-pa2*(sa1-sa2))*10^6; Fbucket measurement = number of oil cylinders * (pc1*sc1-pc2*(sc1-sc2))*10^6; In the formula: pb1 represents the large-cavity cylinder pressure of the boom, pb2 represents the small-cavity cylinder pressure of the boom, sb1 represents the large-cavity cross-sectional area of ​​the boom, sb2 represents the small-cavity cross-sectional area of ​​the boom; pa1 represents the large-cavity cylinder pressure of the arm, pa2 represents the small-cavity cylinder pressure of the arm, sa1 represents the large-cavity cross-sectional area of ​​the arm, sa2 represents the small-cavity cross-sectional area of ​​the boom; pc1 represents the large-cavity cylinder pressure of the bucket, pc2 represents the small-cavity cylinder pressure of the bucket, sc1 represents the large-cavity cross-sectional area of ​​the bucket, and sc2 represents the small-cavity cross-sectional area of ​​the bucket.

5. The method for calculating the impact load of an excavator according to claim 1, characterized in that: The steps of comparing the theoretical mathematical model cylinder force with the actually measured cylinder force at the impact moment to obtain the accurate impact load are: (theoretical mathematical model cylinder force - actually measured cylinder force at the impact moment) / If the value of the theoretical mathematical model cylinder force is less than 5%, the accurate impact load is the theoretical mathematical model cylinder force. Otherwise, it is necessary to re-enter Fmy and Fmz and recalculate until the three cylinder forces match the sizes of the three tested cylinder forces.

6. The method for calculating the impact load of an excavator according to claim 1, characterized in that: The oil cylinder pressure and displacement are acquired by using an oil cylinder pressure sensor and a wire displacement sensor; the movement of the excavator boom, dipper arm and bucket is compounded with the rotation of the rear support.

7. A calculation system for impact load of an excavator, characterized in that: include: Dynamic mathematical model building module, collects the cylinder displacement and pressure of the working device under the dynamic state of the excavator, and builds a theoretical dynamic mathematical model; The module for acquiring the measured cylinder pressure at the impact moment calculates the measured cylinder force at the impact moment based on the collected cylinder force of the working device under the dynamic state of the excavator; The force analysis module calculates the hinge point and bucket tooth motion coordinates through the established dynamic mathematical model. The theoretical mathematical model cylinder force of the working device is calculated through the motion coordinates and the gravity load of the excavator during the movement. The impact load calculation module compares the theoretical mathematical model cylinder force with the measured cylinder force at the impact moment to obtain the accurate impact load.

8. The excavator impact load calculation system according to claim 7, characterized in that: The specific steps of the force analysis module are as follows: the model and size of the working device of the excavator are known, and an AM point is set on the working device of the excavator. The displacement angle of the working device is calculated based on the collected cylinder displacement of the working device. The coordinate positions of each AM hinge point are calculated through the displacement angle. According to the coordinate position and the moment balance method, the moment balance is calculated for the three points A, E, and K respectively, and the theoretical mathematical model cylinder force of the working device can be calculated.

9. The excavator impact load calculation system according to claim 7, characterized in that: The steps of the cylinder force calculation module are: (theoretical mathematical model cylinder force-actually measured cylinder force at the impact moment) / If the value of the theoretical mathematical model cylinder force is less than 5%, the accurate impact load is the theoretical mathematical model cylinder force. Otherwise, Fmy and Fmz need to be re-entered and recalculated until the three cylinder forces match the sizes of the three tested cylinder forces.

10. The excavator impact load calculation system according to any one of claims 7 to 9, characterized in that: The working device comprises a boom, a bucket and a dipper rod, and oil cylinder pressure sensors and wire displacement sensors are respectively arranged on the oil cylinders of the boom, the bucket and the dipper rod.

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