CN102914351B - Weighting method for electric excavator - Google Patents

Abstract

The invention relates to a weighting method for an electric excavator. The weighting method is used for solving the technical problem of ultra-large weighting error of the present method. According to the technical scheme provided by the invention, the weighting method comprises the following steps: taking the center of a saddle as a torque balance point and establishing a rectangular coordinate system by taking the torque balance point as an original point; confirming barycenters of a shovel rod and materials which are fully filled in a bucket and attached to the upper part of the shovel rod, coordinates of acting points of lifting force and pushing force in a coordinate system when the shovel rod is located in a horizontal position, causing a force arm of the pushing force to be equal to a vertical coordinate of the acting point of the pushing force, solving the coordinates of the points at a weighting moment according to a motion track equation of the shovel rod, and causing a gravity force arm to be equal to the horizontal coordinate of the barycenters at the weighting moment; solving a tangent coordinate according to a position relation of the acting point of the lifting force and a tangent point of a lifting steel rope on the right side of a hoisting sheave to the hoisting sheave at the weighting moment, listing a straight line equation of the lifting steel rope, and solving the force arm of the lifting force according to a distance from the center of the saddle to the straight line; adopting a sensor for measuring the pushing force acting on a pushing pulley and a pushing buffer and the lifting force acting on a shovel; and listing a torque equilibrium equation and solving the weight of the materials.

Description

Electric excavator Weighing method

Technical field

The present invention relates to a kind of Weighing method of electric excavator, the method is especially adapted to exempt to turn round weighing of round shovel rod-type electric excavator.

Background technology

Electric excavator is mainly used in the excavation of the soil of glory-hole, rock, ore and coal, is divided into rack-and-pinion push-press type electric excavator according to the difference of pushing mode and exempts to turn round round shovel rod-type electric excavator.Output in the past in order to add up separate unit excavator can only be recorded load wagon number and estimate by special personnel, the numeral come out so not only error is many, also add the input of personnel.

Application number be 200710185462.5 Chinese patent announced a kind of Weighing method of rack-and-pinion push-press type electric excavator, this method calculates the lifting force of wire rope to scraper bowl by the relational expression between the torque on lifting motor and the lifting force of wire rope, calculated by the relational expression between the torque on pushing motor and wire rope pushing force and push the thrust of dipper to scraper bowl, then by swing arm, scrambler measured pushing stroke, in the triangle of lift stroke composition with the cosine law calculate respectively weigh time lifting beam and pushing dipper between angle and angle between lifting beam and hoisting cable, stress balance eventually through scraper bowl calculates the weight of material.

Although the technical scheme of this patent saves manpower, but these computing method have ignored shovel bar and are attached to the impact of other parts gravity on shovel bar, therefore the weight of material calculated according to this technical scheme has larger error, and this art solutions is not suitable with the power shovel of wire rope pushing.

Then the angle cosine law on the right side of the angle in this patent formula between lifting beam and pushing dipper and lifting beam and head sheave between hoisting cable calculates, because the hoisting cable extended line on the right side of the extended line of swing arm and head sheave does not intersect the point of contact on the right side of hoisting cable and head sheave, due to this point of contact relative to head sheave be change, swing arm can not become, padlock is certain deformation relative to shovel bar, the closed figure caused like this is not a real triangle, so utilize the cosine law to cause error.

In addition in this technical scheme, wire rope is calculated by these two power and lifting motor torque and the relational expression that pushes motor torque the lifting force of scraper bowl and pushing dipper to the thrust of scraper bowl respectively, pushing/lifting motor in these two relational expressions is often change to the transmission efficiency between working mechanism exports, and they are all get a fixing value in the calculation, the wire rope therefore calculated like this to the lifting force of scraper bowl and the thrust error of pushing dipper to scraper bowl larger.

Summary of the invention

The object of this invention is to provide the electric excavator Weighing method that a kind of accuracy is higher.

Technical scheme of the present invention is:

1, a Weighing method for electric excavator, is characterized in that comprising the steps:

1) to shovel saddle center when bar is horizontal for O point, be Y-axis perpendicular to the earth direction, being parallel to Athey wheel base direction is X-axis, sets up rectangular coordinate system,

Determine that shovel bar is in level and on the right side of head sheave, hoisting cable is perpendicular in described coordinate-system during shovel bar position, full bucket material barycentric coordinates are (x ₀, y ₀), shovel bar and to be attached to the overall barycentric coordinates that shovel bar upper-part forms be (x ₁, y ₁), pushing wire rope is (x with pushing pulley tie point coordinate ₂, y ₂), pushing wire rope with pushing impact damper tie point coordinate be (x ₃, y ₃), the coordinate of hoisting cable and scraper bowl connecting with padlock contact is (x ₄, y ₄), the central coordinate of circle of head sheave is (x ₅, y ₅);

2) with the displacement transducer of afterbody being arranged on shovel bar record weigh time shovel bar and be attached to the integrant horizontal displacement Δ x of shovel bar upper-part, record shovel bar with the obliquity sensor be arranged on shovel bar or saddle and be attached to shovel bar upper-part the integrant angle α with X-axis;

3) the center of gravity horizontal ordinate x ' of full bucket material when weighing with following rotation of coordinate formulae discovery ₀, shovel bar and be attached to shovel bar upper-part integrant center of gravity horizontal ordinate x ' ₁, hoisting cable and scraper bowl tie point coordinate (x ' ₄, y ' ₄),

x′ ₀＝(x ₀+Δx)×cosα-y ₀×sinα (1)

x′ ₁＝(x ₁+Δx)×cosα-y ₁×sinα (2)

x′ ₄＝(x ₄+Δx)×cosα-y ₄×sinα (3)

y′ ₄＝(x ₄+Δx)×sinα+y ₄×cosα (4)

4) coordinate (x at hoisting cable and head sheave point of contact on the right side of head sheave when being weighed by following formulae discovery ₆, y ₆),

Scraper bowl on the left of head sheave,

x ₆＝x′ ₄+L ₂×cos(β ₂-β ₁) (5)

y ₆＝y′ ₄+L ₂×sin(β ₂-β ₁) (6)

Scraper bowl on the right side of head sheave,

x ₆＝x′ ₄-L ₂×cos(β ₁+β ₂) (7)

y ₆＝y′ ₄+L ₂×sin(β ₁+β ₂) (8)

In formula (5), (6), (7) and (8), L ₂be with absolute value encoder record weigh time head sheave on the right side of the length of hoisting cable, obtain with following formulae discovery,

$L_2=\frac{C_i-C_0}{C_n-C_0}\×L---\left(9\right)$

In formula (9), C ₀the numerical value that hoisting cable is pulled to that scrambler is corresponding the most in short-term, C _nthe hoisting cable numerical value that scrambler is corresponding when being pulled to the longest, C _ibe scrambler numerical value when weighing corresponding to hoisting cable length, L is C ₀to C _ncorresponding hoisting cable length;

In formula (5), (6), (7) and (8), β ₁hoisting cable between head sheave and scraper bowl when weighing, with the head sheave center of circle (x ₅, y ₅) to hoisting cable and scraper bowl connecting with padlock contact (x ' ₄, y ' ₄) the angle of line, can obtain with following formulae discovery,

${\mathrm{\β}}_1={\sin }^{-1}\frac{r}{\sqrt{r^2+L_2^2}}---\left(10\right)$

In formula (10), r is head sheave radius;

In formula (5), (6), (7) and (8), β ₂the head sheave center of circle (x when weighing ₅, y ₅) to hoisting cable and scraper bowl connecting with padlock contact (x ' ₄, y ' ₄) line and the angle of X-axis, available following formulae discovery obtains,

${\mathrm{\β}}_2={\tan }^{-1}\left|\frac{y_5-y_4^{\′}}{x_4^{\′}-x_5}\right|---\left(11\right)$

5) by following formulae discovery hoisting cable tensile force f ₁arm of force D ₁,

$D_1=\frac{|-\frac{y_4^{\′}-y_6}{x_4^{\′}-x_6}\×x_6+y_6|}{\sqrt{{\left(\frac{y_4^{\′}-y_6}{x_4^{\′}-x_5}\right)}^2+1}}---\left(12\right)$

6) with the tension pick-up be arranged between arm carrier and hoisting cable record weigh time hoisting cable tensile force f ₁,

$F_1=\frac{F_1^{\′}}{(\cos {\mathrm{\γ}}_{11}+\cos {\mathrm{\γ}}_{12})}---\left(13\right)$

In formula (13), F ' ₁be mounted in the pressure that the tension pick-up between arm carrier and hoisting cable records, γ ₁₁and γ ₁₂hoisting cable and the angle being arranged on the tension pick-up central shaft between arm carrier and hoisting cable,

7) the thrust F on pushing pulley is acted on following formulae discovery pushing wire rope ₂

$F_2=F_2^{\′\′}\×\frac{(\cos {\mathrm{\γ}}_{21}+\cos {\mathrm{\γ}}_{22})}{(\cos {\mathrm{\γ}}_{23}+\cos {\mathrm{\γ}}_{24})}---\left(14\right)$

In formula (14), γ ₂₁and γ ₂₂the pushing wire rope at pushing pulley place and the angle of shovel bar respectively, γ ₂₃and γ ₂₄be pushing wire rope respectively and be arranged on arm carrier and push the angle of tension pick-up central shaft between wire rope, F " ₂shovel when bar advances to ore body with the pressure be arranged between arm carrier and pushing wire rope measured by tension pick-up;

8) the power F on pushing impact damper is acted on following formulae discovery pushing wire rope ₃

$F_3=F_3^{\′\′}\×\frac{(\cos {\mathrm{\γ}}_{31}+\cos {\mathrm{\γ}}_{32})}{(\cos {\mathrm{\γ}}_{23}+\cos {\mathrm{\γ}}_{24})}---\left(15\right)$

In formula (15), γ ₃₁and γ ₃₂the pushing wire rope at pushing impact damper place and the angle of shovel bar respectively, F " ₃shovel when bar is withdrawn from from ore body with pressure measured by the tension pick-up be arranged between arm carrier and pushing wire rope;

9) push wire rope by following formulae discovery and act on pushing pulley lifting force F ₂arm of force D ₂impact damper lifting force F is pushed with acting on ₃arm of force D ₃,

D ₂＝y ₂ (16)

D ₃＝y ₃ (17)

10) according to the quality of shovel stick force square EQUILIBRIUM CALCULATION FOR PROCESS material,

$M=\frac{F_1\×D_1+(1-s)\×F_3\×D_3-s\×F_2\×D_2-G_1\×x_1^{\′}}{x_0^{\′}\×g}---\left(18\right)$

In formula (18), G ₁be shovel bar and be attached to the integrant gravity of shovel bar upper-part, g is that acceleration of gravity gets 9.8N/m ², s is a coefficient, and when shovel bar advances to ore body, s equals 1, and when shoveling bar and withdrawing from from ore body, s equals 0.

The gravity that technical scheme of the present invention considers shovel bar, the pushing pulley of shovel bar afterbody, pushing impact damper between shovel bar and scraper bowl, scraper bowl and is attached to the padlock on scraper bowl is on the impact of shoveling bar equalising torque, and be the shovel bar torque equilibrium equation built for equilibrium point with saddle center, thus eliminate the saddle indefinite power that this crosses saddle center on the anchorage force of shovel bar to the impact of shovel bar equalising torque, improve weighing accuracy.

Shoveling bar inclination angle in the technical program to record with being arranged on shovel bar afterbody obliquity sensor, having following two advantages compared with the shovel bar inclination angle drawn by account form: 1, efficiency is high, needing to spend the more time because calculate inclination angle, 2, accuracy is high.

The hoisting cable of the technical program acts on the pulling force on scraper bowl and wire rope acts on pushing pulley and the thrust pushed on impact damper is all directly recorded by the sensor be arranged on arm carrier, and accuracy is high.

Accompanying drawing explanation

Fig. 1 electric excavator is weighed view

Fig. 2 shovels stressed schematic diagram in bar motion process

The position relationship schematic diagram of head sheave and scraper bowl when scraper bowl is on the right side of head sheave when Fig. 3 weighs

The position relationship schematic diagram of head sheave and scraper bowl when scraper bowl is on the left of head sheave when Fig. 4 weighs

Fig. 5 arm carrier is surveyed the stressed schematic diagram of tension pick-up of hoisting cable pulling force

Pulley stressed schematic diagram is pushed when Fig. 6 weighs

Fig. 7 arm carrier is surveyed the stressed schematic diagram of tension pick-up of pushing lineoutofservice signal pull

Impact damper stressed schematic diagram is pushed when Fig. 8 weighs

Embodiment

Below in conjunction with embodiment, the solution of the present invention is further described

As shown in Figure 1, electric excavator is generally made up of travel mechanism 1, hoisting gear 2, slew gear 3, dipper crowding gear 4 and electric part.Electric excavator takes to and excavates destination by travel mechanism 1; The scraper bowl 10 that dipper crowding gear 4 pulls the promotion of pushing wire rope 5 to be fixedly mounted on shovel bar 9 shovels into ore body; Hoisting gear 2 pulls hoisting cable 6 upwards to mention and is fixedly mounted on the scraper bowl 10 shoveled on bar 9, makes ore fill scraper bowl 10, and rest on the height higher than electric power wheel self-discharging vehicle vehicle body; Slew gear 3 forwards from ore body sidespin the scraper bowl 10 filling ore to electric power wheel self-discharging vehicle side, and then scraper bowl 10 is opened, and ore is poured in self-unloading wheel car, and then electric excavator goes back to original position, and hoisting gear puts down scraper bowl, repeats a work period.

From the electric excavator course of work, when electric excavator is in turning course, the steady quality of ore body in scraper bowl, and be the quality finally pouring ore body in self-unloading wheel car into, in addition the position of scraper bowl is also relatively-stationary, and therefore turning course is best opportunity of weighing.

As shown in Figure 2, in the whole mining process of electric excavator, shovel bar is mainly by shovel bar and the Action of Gravity Field being attached to ore in other parts and scraper bowl on shovel bar, and other External Force Acting.Shovel bar and be attached to other parts on shovel bar mainly comprise shovel bar 9, scraper bowl 10, shovel bar afterbody pushing pulley 11, be located at the padlock 14 on scraper bowl and the pushing impact damper 13 between shovel bar and scraper bowl.Other external force acted on shovel bar mainly comprises pushing wire rope and acts on the thrust F pushed towards ore side on pulley ₂, pushing wire rope acts on pushing impact damper and carries on the back the thrust F of ore side ₃, hoisting cable acts on the tensile force f on scraper bowl ₁, and saddle to shovel bar anchorage force F ₄.Wherein act on the thrust F towards ore side on pushing pulley ₂the thrust F of ore side is carried on the back with acting on pushing impact damper ₃both can only have one, because apply to the thrust of ore side or the thrust to scraper bowl applying back of the body ore side scraper bowl at synchronization pushing wire rope.

The foundation of weighing is the equalising torque of shovel bar, in order to eliminate the anchorage force F of saddle to shovel bar ₄this power being difficult to measure is on the impact of shovel bar equalising torque, and also in order to simplify the analysis of equalising torque, what the equilibrium point shoveling stick force square was selected is saddle center.

First the gravity torque acting on equalising torque point two ends is analyzed, shovel bar and be attached to shovel bar on other parts after finalization of the manufacture, its center of gravity and gravity also just can be determined, completely during bucket, the center of gravity of material is constant relative to the position of scraper bowl, therefore completely bucket material center of gravity also can be determined, therefore next step is exactly the gravity arm of force will tried to achieve shovel bar and be attached to other parts and full bucket material on shovel bar, namely shovels bar and to be attached on shovel bar other parts and material relative to the position of equalising torque point.But because each excavation surface of electric excavator all can be different, the height that the scraper bowl filling ore promotes is also different, therefore shoveling bar and be attached to the center of gravity of shoveling other parts and material on bar also can be different relative to equalising torque point position.

By analysis, can finding that the mining track of electric excavator is determined jointly by pushing wire rope and hoisting cable: scraper bowl is pushed ore body by exerting a force on the pushing pulley of shovel bar by pushing wire rope, by exerting a force on the pushing impact damper of shovel bar scraper bowl being withdrawn from ore body; Hoisting cable hauls scraper bowl by force on scraper bowl padlock and rotates up and down around saddle center.

Therefore to know that the center of gravity of to shovel bar when weighing and being attached to other parts and material on shovel bar is relative to equalising torque point position, we need to determine an initial position, determine now to shovel the position of center of gravity relative to equalising torque point of other parts and material on bar, then measure and shovel bar when weighing relative to the distance advancing or withdraw from ore body during initial position, shovel bar relative to the angle rotated during initial position, shovel bar when just can go out weigh by rotation of coordinate formulae discovery and be attached to shovel other parts and material on bar center of gravity relative to equalising torque point position.Obvious shovel bar be in level and on the right side of head sheave hoisting cable perpendicular to shovel bar position be a most convenient subsequent calculations initial position.For simplifying the analysis the movement locus of shovel bar is decomposed into the state of three shown in Fig. 2.Wherein first state is horizontal for shoveling bar, and second state is that shovel bar level stretches into or withdraw from ore body, and the 3rd state is that shovel bar promotes complete, enters gyration.

For the ease of follow-up calculating, as shown in step 1 we with saddle center for initial point establishes rectangular coordinate system, so both can eliminate saddle to shovel bar anchorage force to the impact of equalising torque, also the calculating of the follow-up lifting force arm of force is facilitated, and when being in first excavation state with scraper bowl, namely shovel bar is horizontal state is the center of gravity that initial position is determined to shovel bar and be attached to shovel bar upper-part, the center of gravity of full bucket material is (although the material in initial position scraper bowl is discontented certainly, but be in full bucket material centre of gravity place when weighing state is constant relative to scraper bowl, therefore the coordinate of the full bucket material center of gravity of initial position relative to equalising torque position can still be determined), with the coordinate of other external force application point on shovel bar.

1) to shovel saddle center when bar is horizontal for O point, be Y-axis perpendicular to the earth direction, being parallel to Athey wheel base direction is X-axis, sets up rectangular coordinate system,

Determine that shovel bar is in level and on the right side of head sheave, hoisting cable is perpendicular in described coordinate-system during shovel bar position, full bucket material barycentric coordinates are (x ₀, y ₀), shovel bar and to be attached to the overall barycentric coordinates that shovel bar upper-part forms be (x ₁, y ₁), pushing wire rope is (x with pushing pulley tie point coordinate ₂, y ₂), pushing wire rope with pushing impact damper tie point coordinate be (x ₃, y ₃), the coordinate of hoisting cable and scraper bowl connecting with padlock contact is (x ₄, y ₄), the central coordinate of circle of head sheave is (x ₅, y ₅);

Behind the original center of gravity position determining shovel bar and be attached to shovel bar upper-part, by known next step of analysis be above exactly to know shovel bar from initial position actually level stretch into ore body how far distance and upwards promote to have rotated how many angles.As shown in step 2 below, the distance that shovel bar level stretches into ore body can be recorded by the displacement transducer of the afterbody being arranged on shovel bar, and the inclination angle of shovel bar, namely shovels the angle of bar and X-axis, then the obliquity sensor by being arranged on shovel bar afterbody records,

2) with the displacement transducer of afterbody being arranged on shovel bar record weigh time shovel bar and be attached to the integrant horizontal displacement Δ x of shovel bar upper-part, record shovel bar with the obliquity sensor be arranged on shovel bar or saddle and be attached to shovel bar upper-part the integrant angle α with X-axis;

Shovel bar when known initial position and be attached to shovel bar upper-part, full bucket material barycentric coordinates, and shovel bar and be attached to the center of gravity of shovel bar upper-part, full bucket material when just can obtain weighing by rotational coordinates formulae discovery as described in step 3 shovel angle that Distance geometry that bar level stretched into or withdrew from ore body rotates up by initial position after, and the coordinate of the application point of other external force.Owing to calculating the horizontal ordinate that shovel bar equalising torque only needs to use shovel bar and be attached to shovel bar upper-part and full bucket material center of gravity, therefore step 3 just no longer calculates shovel bar and is attached to the ordinate of shovel bar upper-part and material center of gravity.

The center of gravity horizontal ordinate x ' of full bucket material when weighing with following rotation of coordinate formulae discovery ₀, shovel bar and be attached to shovel bar upper-part integrant center of gravity horizontal ordinate x ' ₁, hoisting cable and scraper bowl tie point coordinate (x ' ₄, y ' ₄),

x′ ₀＝(x ₀+Δx)×cosα-y ₀×sinα (1)

x′ ₁＝(x ₁+Δx)×cosα-y ₁×sinα (2)

x′ ₄＝(x ₄+Δx)×cosα-y ₄×sinα (3)

y′ ₄＝(x ₄+Δx)×sinα+y ₄×cosα (4)

By step 3 calculated weigh state time shovel bar and the coordinate of other parts center of gravity that is attached on shovel bar, gravity torque can be determined, next step is exactly ask the moment acting on external force on shovel bar.

From the lifting moment of hoisting cable, first ask hoisting cable tensile force f ₁the arm of force, the straight-line equation that this arm of force first must try to achieve hoisting cable place on the right side of head sheave be tried to achieve, then tried to achieve by the range formula of saddle center to this straight line.As shown in Figure 3, Figure 4, on the right side of head sheave hoisting cable have one with the tie point of scraper bowl padlock (x ' ₄, y ' ₄) and one with the point of contact (x of head sheave ₆, y ₆), due to scraper bowl padlock tie point (x ' ₄, y ' ₄) simultaneously also on the attachment members of shovel bar, therefore can be calculated by step 3.And the point of contact (x of hoisting cable and head sheave ₆, y ₆), do not shoveling bar and be attached on the parts of shovel bar, then calculated by it and the position relationship of hoisting cable and scraper bowl tie point when weighing, according to the position relationship of scraper bowl and head sheave, can be divided into scraper bowl on the left of head sheave with scraper bowl two kinds of situations on the right side of head sheave.

When scraper bowl is on the right side of head sheave, as shown in Figure 3, with the hoisting cable on the right side of head sheave for hypotenuse, to cross point of contact (x on the right side of hoisting cable and head sheave ₆, y ₆) and be parallel to Y-axis straight line, cross hoisting cable and scraper bowl padlock tie point (x ' ₄, y ' ₄) and the straight line being parallel to X-axis is in the right-angle triangle of right-angle side, hoisting cable length L when weighing on the right side of head sheave ₂shown in (9), can be recorded by absolute value encoder, rise wire rope and scraper bowl padlock tie point (x ' ₄, y ' ₄) be known, therefore only require to obtain the angle of hoisting cable and X-axis, just successfully can try to achieve the point of contact (x of hoisting cable and head sheave ₆, y ₆).The angle of hoisting cable and X-axis, can be decomposed into the angle β to hoisting cable and connecting with padlock contact line of hoisting cable and the head sheave center of circle on the right side of head sheave ₁, with the head sheave center of circle to hoisting cable and the line of connecting with padlock contact and the angle β of X-axis ₂.

When scraper bowl is on the left of head sheave, as shown in Figure 4, now the angle of hoisting cable and X-axis is the head sheave center of circle to hoisting cable and the line of connecting with padlock contact and the angle β of X-axis ₂, with hoisting cable on the right side of head sheave and the head sheave center of circle to the angle β of hoisting cable and connecting with padlock contact line ₁difference.

Due to the hoisting cable length L on the right side of the radius r of head sheave and head sheave ₂known, therefore in the right-angle triangle be made up of the line at hoisting cable and head sheave point of contact on the right side of hoisting cable, the head sheave center of circle to head sheave on the right side of head sheave, the head sheave center of circle to the line of hoisting cable and scraper bowl connecting with padlock contact, therefore β ₁can try to achieve with the arcsin function of step 4 formula (10).Coordinate (the x in the head sheave center of circle ₅, y ₅) and hoisting cable and scraper bowl connecting with padlock contact coordinate (x ' ₄, y ' ₄) determined before step 4, therefore β ₂can try to achieve with arctan function.But consider that when weighing, scraper bowl in the left side of head sheave, also may, on the right side of head sheave, may need to calculate by following two formulas respectively,

Scraper bowl on the right side of head sheave,

${\mathrm{\β}}_2={\tan }^{-1}\frac{y_5-y_4^{\′}}{x_4^{\′}-x_5}$

Scraper bowl on the left of head sheave,

${\mathrm{\β}}_2={\tan }^{-1}\frac{y_5-y_4^{\′}}{{x_5-x}_4^{\′}}$

Obviously can by above-mentioned calculating β ₂these two formulas are merged into the formula (11) of step (4),

4) coordinate (x at hoisting cable and head sheave point of contact on the right side of head sheave when being weighed by following formulae discovery ₆, y ₆),

Scraper bowl on the left of head sheave,

x ₆＝x′ ₄+L ₂×cos(β ₂-β ₁) (5)

y ₆＝y′ ₄+L ₂×sin(β ₂-β ₁) (6)

Scraper bowl on the right side of head sheave,

x ₆＝x′ ₄-L ₂×cos(β ₁+β ₂) (7)

y ₆＝y′ ₄+L ₂×sin(β ₁+β ₂) (8)

In formula (5), (6), (7) and (8), L ₂be with absolute value encoder record weigh time head sheave on the right side of the length of hoisting cable, obtain with following formulae discovery,

$L_2=\frac{C_i-C_0}{C_n-C_0}\×L---\left(9\right)$

In formula (9), C ₀the numerical value that hoisting cable is pulled to that scrambler is corresponding the most in short-term, C _nthe hoisting cable numerical value that scrambler is corresponding when being pulled to the longest, C _ibe scrambler numerical value when weighing corresponding to hoisting cable length, L is C ₀to C _ncorresponding hoisting cable length;

In formula (5), (6), (7) and (8), β ₁hoisting cable between head sheave and scraper bowl when weighing, with the head sheave center of circle (x ₅, y ₅) to hoisting cable and scraper bowl connecting with padlock contact (x ' ₄, y ' ₄) the angle of line, can obtain with following formulae discovery,

${\mathrm{\β}}_1={\sin }^{-1}\frac{r}{\sqrt{r^2+L_2^2}}---\left(10\right)$

In formula (10), r is head sheave radius;

In formula (5), (6), (7) and (8), β ₂the head sheave center of circle (x when weighing ₅, y ₅) to hoisting cable and scraper bowl connecting with padlock contact (x ' ₄, y ' ₄) line and the angle of X-axis, available following formulae discovery obtains,

${\mathrm{\β}}_2={\tan }^{-1}\left|\frac{y_5-y_4^{\′}}{x_4^{\′}-x_5}\right|---\left(11\right)$

Try to achieve the point of contact coordinate (x of hoisting cable and head sheave on the right side of head sheave ₆, y ₆) and hoisting cable and scraper bowl padlock tie point coordinate (x ' ₄, y ' ₄) by 2, just can be shown below determines that straight line theorems list the equation of hoisting cable place straight line on the right side of head sheave,

$\frac{x-x_6}{x_6-x_4^{\′}}=\frac{y-y_4^{\′}}{y_6-y_4^{\′}}$

Conveniently with the distance calculating lifting force arm of force of point to straight line, the equation of hoisting cable place straight line on the right side of head sheave is above changing into following standard straight-line equation,

$\frac{y_4^{\′}-y_6}{x_4^{\′}-x_6}\×x-y-\frac{y_4^{\′}-y_6}{x_4^{\′}-x_6}\×x_6+y_6=0$

List the equation of hoisting cable place straight line on the right side of head sheave, just as described in step 5 below, the distance of hoisting cable on the right side of saddle center to head sheave when weighing can be obtained, i.e. the arm of force of lifting force.

5) by following formulae discovery hoisting cable tensile force f ₁arm of force D ₁,

$D_1=\frac{|-\frac{y_4^{\′}-y_6}{x_4^{\′}-x_6}\×x_6+y_6|}{\sqrt{{\left(\frac{y_4^{\′}-y_6}{x_4^{\′}-x_5}\right)}^2+1}}---\left(12\right)$

The hoisting cable pulling force acted on scraper bowl records with the tension pick-up be arranged between arm carrier and hoisting cable, as shown in Figure 5, the dynamometry end that this tension pick-up 16 has one to contact with hoisting cable, dynamometry end can by hoisting cable jack-up, the pressure F ' now measured by tension pick-up ₁be equivalent to the tensile force f of two sections of hoisting cables ₁making a concerted effort along tension pick-up dynamometry end axis, and when installation tension sensor, the angle γ of these two sections of wire rope and tension pick-up dynamometry end ₁₁and γ ₁₂just can determine, therefore the pressure F ' that records of tension pick-up ₁with the tensile force f of hoisting cable ₁meet following relationship:

$F_1=\frac{F_1^{\′}}{(\cos {\mathrm{\γ}}_{11}+\cos {\mathrm{\γ}}_{12})}$

6) with the tension pick-up be arranged between arm carrier and hoisting cable record weigh time hoisting cable tensile force f ₁,

$F_1=\frac{F_1^{\′}}{(\cos {\mathrm{\γ}}_{11}+\cos {\mathrm{\γ}}_{12})}---\left(13\right)$

In formula (13), F ' ₁be mounted in the pressure that the tension pick-up between arm carrier and hoisting cable records, γ ₁₁and γ ₁₂hoisting cable and the angle being arranged on the tension pick-up central shaft between arm carrier and hoisting cable,

When shoveling bar and advancing to ore body, pushing wire rope only has the thrust F acted on towards ore side on pushing pulley 11 ₂, as shown in Figure 6, this power be equivalent to two sections lay respectively at (being equivalent to set up rectangular coordinate system Z-direction) of side before and after shovel bar push tensile force f on wire rope 5 ' ₂along shovel bar towards ore body direction make a concerted effort, these two sections pushing wire rope with shovel bar angles be respectively γ ₂₁and γ ₂₂, obviously act on the thrust F of pushing pulley 11 ₂with pushing wire rope 5 on tensile force f ' ₂meet following relationship:

F ₂＝F′ ₂×(cosγ ₂₁+cosγ ₂₂)

As shown in Figure 7, push wire rope 5 tensile force f ' ₂be record with the tension pick-up 18 be arranged between arm carrier and pushing wire rope, pushing wire rope 5 is respectively and γ with the angle of tension pick-up 18 dynamometry end central shaft ₂₃and γ ₂₄, the same with the analysis of lifting force, pushing wire rope 5 tensile force f ' ₂and be arranged on the pressure F that the tension pick-up between arm carrier and pushing wire rope records " ₂relation be:

$F_2^{\′}=\frac{F_2^{\′\′}}{(\cos {\mathrm{\γ}}_{23}+\cos {\mathrm{\γ}}_{24})}$

Merge the formula (17) that above-mentioned two formulas can obtain step 7.

When shoveling bar and withdrawing from from ore body, pushing wire rope only acts on the power F on pushing impact damper ₃, as shown in Figure 8, pushing wire rope is respectively γ at pushing impact damper place and the angle of shovel bar ₃₁and γ ₃₂, obviously pushing wire rope acts on the thrust F of pushing impact damper along shovel bar back of the body ore body direction ₃with pushing wire rope tensile force f ' ₃meet following relationship:

F ₃＝F′ ₃×(cosγ ₃₁+cosγ ₃₂)

Owing to acting on the thrust F of pushing pulley ₂with the thrust F on pushing impact damper ₃all applied by same steel cable (pushing wire rope), therefore be arranged on the tension pick-up 18 between arm carrier and pushing wire rope both can measure shovel to push when bar advances to ore body tensile force f on wire rope ' ₂can measure again the tensile force f of shovel bar when withdrawing from from ore body pushing wire rope ' ₃, as shown in Figure 7, shovel bar when withdrawing from from ore body pushing wire rope and the angle of tension pick-up 18 dynamometry end central shaft that is arranged between arm carrier and pushing wire rope be respectively γ ₂₃and γ ₂₄, the pressure F that tension pick-up 18 records " ₃with pushing wire rope on tensile force f ' ₃meet following relationship:

$F_3^{\′}=\frac{F_3^{\′\′}}{\cos {\mathrm{\γ}}_{23}+\cos {\mathrm{\γ}}_{24}}$

7) the thrust F on pushing pulley is acted on following formulae discovery pushing wire rope ₂

$F_2=F_2^{\′\′}\×\frac{(\cos {\mathrm{\γ}}_{21}+\cos {\mathrm{\γ}}_{22})}{(\cos {\mathrm{\γ}}_{23}+\cos {\mathrm{\γ}}_{24})}---\left(14\right)$

In formula (14), γ ₂₁and γ ₂₂the pushing wire rope at pushing pulley place and the angle of shovel bar respectively, γ ₂₃and γ ₂₄be pushing wire rope respectively and be arranged on arm carrier and push the angle of tension pick-up central shaft between wire rope, F " ₂shovel when bar advances to ore body with the pressure be arranged between arm carrier and pushing wire rope measured by tension pick-up;

8) the power F on pushing impact damper is acted on following formulae discovery pushing wire rope ₃

$F_3=F_3^{\′\′}\×\frac{(\cos {\mathrm{\γ}}_{31}+\cos {\mathrm{\γ}}_{32})}{(\cos {\mathrm{\γ}}_{23}+\cos {\mathrm{\γ}}_{24})}---\left(15\right)$

In formula (15), γ ₃₁and γ ₃₂the pushing wire rope at pushing impact damper place and the angle of shovel bar respectively, F " ₃shovel when bar is withdrawn from from ore body with pressure measured by the tension pick-up be arranged between arm carrier and pushing wire rope;

Act on the thrust F on pushing pulley ₂with the thrust F acted on pushing impact damper ₃all the time along shovel bar direction, and shovel bar around saddle central rotation, therefore saddle center can not change to the distance of shovel bar, and as shown in step 9 below, the arm of force of these two power just equals the ordinate of these two power initial position application point on shovel bar.

9) push wire rope by following formulae discovery and act on the thrust F pushed on pulley ₂arm of force D ₂with the thrust F acted on pushing impact damper ₃arm of force D ₃,

D ₂＝y ₂ (16)

D ₃＝y ₃ (17)

By the shovel bar of trying to achieve above and be attached to the equalising torque formula that the gravity of other parts, its external force and their moment on shovel bar lists shovel bar and be:

F ₁×D ₁+(1-s)×F ₃×D ₃＝s×F ₂×D ₂+G ₁×x ₁+M×g×x ₀

The formula asking full bucket material quality described in step 10 is changing into by above-mentioned equalising torque formula

10) according to the quality of shovel stick force square EQUILIBRIUM CALCULATION FOR PROCESS material,

$M=\frac{F_1\×D_1+(1-s)\×F_3\×D_3-s\×F_2\×D_2-G_1\×x_1^{\′}}{x_0^{\′}\×g}---\left(18\right)$

In formula (18), G ₁be shovel bar and be attached to the integrant gravity of shovel bar upper-part, g is that acceleration of gravity gets 9.8N/m ², s is a coefficient, and when shovel bar advances to ore body, s equals 1, and when shoveling bar and withdrawing from from ore body, s equals 0.

When shovel bar be in weigh state time, scraper bowl may be in the state of deep excavation ore body, now only acts on pushing pulley towards the thrust of ore body side, and does not act on the thrust of pushing impact damper being carried on the back ore body side; Scraper bowl also may be in the state withdrawing from ore body, now only acts on the thrust of pushing impact damper back of the body ore body side, does not act on the thrust of pushing pulley towards ore body side.

After revolution starts, start check weighing after 0.3 to 0.7 second, when can prevent revolution from starting, scraper bowl is still in workplace, and revolution starts also not easily oversize to the time started between check weighing, to stop the enough time to weighing.

When power shovel is in turning course, although coordinate system is in the state of geo-stationary, but it moves in three dimensions really, power shovel in motion brings interference to possibly the signals collecting of native system, the change of the external environment such as electricity, magnetic, light bring certain interference, meanwhile, due to the difference of operation technique also can to the collection of signal in addition, sometimes power shovel also departs from place of working face sensor completely and just starts transmission of signal, and this also can cause error.Therefore in order to ensure the accuracy of weighing, our weighing results adds the step of a screening, the full bucket material mass value Mn of setting power shovel, when weighing results M is less than 5% of Mn or be greater than 120% of Mn, then this result of weighing, refuses value not in the reasonable scope; Be greater than 5% of Mn as weighing results M and be less than 120% of Mn, then this result of weighing, gives value in the reasonable scope.

Claims (3)

1. a Weighing method for electric excavator, is characterized in that comprising the steps:

1) to shovel saddle center when bar is horizontal for O point, be Y-axis perpendicular to the earth direction, being parallel to Athey wheel base direction is X-axis, sets up rectangular coordinate system,

Determine that shovel bar is in level and on the right side of head sheave, hoisting cable is perpendicular in described coordinate-system during shovel bar position, full bucket material barycentric coordinates are (x ₀, y ₀), shovel bar and to be attached to the overall barycentric coordinates that shovel bar upper-part forms be (x ₁, y ₁), pushing wire rope is (x with pushing pulley tie point coordinate ₂, y ₂), pushing wire rope with pushing impact damper tie point coordinate be (x ₃, y ₃), the coordinate of hoisting cable and scraper bowl connecting with padlock contact is (x ₄, y ₄), the central coordinate of circle of head sheave is (x ₅, y ₅);

2) with the displacement transducer of afterbody being arranged on shovel bar record weigh time shovel bar and be attached to the integrant horizontal displacement Δ x of shovel bar upper-part, record shovel bar with the obliquity sensor be arranged on shovel bar or saddle and be attached to shovel bar upper-part the integrant angle α with X-axis;

3) the center of gravity horizontal ordinate x ' of full bucket material when weighing with following rotation of coordinate formulae discovery ₀, shovel bar and be attached to shovel bar upper-part integrant center of gravity horizontal ordinate x ' ₁, hoisting cable and scraper bowl tie point coordinate (x ' ₄, y ' ₄),

x′ ₀＝(x ₀+Δx)×cosα-y ₀×sinα (1)

x′ ₁＝(x ₁+Δx)×cosα-y ₁×sinα (2)

x′ ₄＝(x ₄+Δx)×cosα-y ₄×sinα (3)

y′ ₄＝(x ₄+Δx)×sinα+y ₄×cosα (4)

4) coordinate (x at hoisting cable and head sheave point of contact on the right side of head sheave when being weighed by following formulae discovery ₆, y ₆),

Scraper bowl on the left of head sheave,

x ₆＝x′ ₄+L ₂×cos(β ₂-β ₁) (5)

y ₆＝y′ ₄+L ₂×sin(β ₂-β ₁) (6)

Scraper bowl on the right side of head sheave,

x ₆＝x′ ₄-L ₂×cos(β ₁+β ₂) (7)

y ₆＝y′ ₄+L ₂×sin(β ₁+β ₂) (8)

In formula (5), (6), (7) and (8), L ₂be with absolute value encoder record weigh time head sheave on the right side of the length of hoisting cable, obtain with following formulae discovery,

$L_2=\frac{C_i-C_0}{C_n-C_0}\×L---\left(9\right)$

In formula (9), C ₀the numerical value that hoisting cable is pulled to that scrambler is corresponding the most in short-term, C _nthe hoisting cable numerical value that scrambler is corresponding when being pulled to the longest, C _ibe scrambler numerical value when weighing corresponding to hoisting cable length, L is C ₀to C _ncorresponding hoisting cable length;

In formula (5), (6), (7) and (8), β ₁hoisting cable between head sheave and scraper bowl when weighing, with the head sheave center of circle (x ₅, y ₅) to hoisting cable and scraper bowl connecting with padlock contact (x ' ₄, y ' ₄) the angle of line, can obtain with following formulae discovery,

${\mathrm{\β}}_1={\sin }^{-1}\frac{r}{\sqrt{r^2+L_2^2}}---\left(10\right)$

In formula (10), r is head sheave radius;

In formula (5), (6), (7) and (8), β ₂the head sheave center of circle (x when weighing ₅, y ₅) to hoisting cable and scraper bowl connecting with padlock contact (x ' ₄, y ' ₄) line and the angle of X-axis, available following formulae discovery obtains,

${\mathrm{\β}}_2={\tan }^{-1}\left|\frac{y_5-y_4^{\′}}{x_4^{\′}-x_5}\right|---\left(11\right)$

5) by following formulae discovery hoisting cable tensile force f ₁arm of force D ₁,

$D_1=\frac{\text{|-}\frac{y_4^{\′}-y_6}{x_4^{\′}-x_6}\×x_6+y_6|}{\sqrt{{\left(\frac{y_4^{\′}-y_6}{x_4^{\′}-x_6}\right)}^2+1}}---\left(12\right)$

6) with the tension pick-up be arranged between arm carrier and hoisting cable record weigh time hoisting cable tensile force f ₁,

$F_1=\frac{F_1^{\′}}{(\cos {\mathrm{\γ}}_{11}+{\cos \mathrm{\γ}}_{12})}---\left(13\right)$

In formula (13), F ' ₁be mounted in the pressure that the tension pick-up between arm carrier and hoisting cable records, γ ₁₁and γ ₂₂hoisting cable and the angle being arranged on the tension pick-up central shaft between arm carrier and hoisting cable,

7) the thrust F on pushing pulley is acted on following formulae discovery pushing wire rope ₂

$F_2=F_2^{\′\′}\×\frac{({\cos \mathrm{\γ}}_{21}+{\cos \mathrm{\γ}}_{22})}{({\cos \mathrm{\γ}}_{23}+{\cos \mathrm{\γ}}_{24})}---\left(14\right)$

In formula (14), γ ₂₁and γ ₂₂the pushing wire rope at pushing pulley place and the angle of shovel bar respectively, γ ₂₃and γ ₂₄be pushing wire rope respectively and be arranged on arm carrier and push the angle of tension pick-up central shaft between wire rope, F " ₂shovel when bar advances to ore body with the pressure be arranged between arm carrier and pushing wire rope measured by tension pick-up;

8) the power F on pushing impact damper is acted on following formulae discovery pushing wire rope ₃

$F_3=F_3^{\′\′}\×\frac{({\cos \mathrm{\γ}}_{31}+{\cos \mathrm{\γ}}_{32})}{({\cos \mathrm{\γ}}_{23}+{\cos \mathrm{\γ}}_{24})}---\left(15\right)$

In formula (15), γ ₃₁and γ ₃₂the pushing wire rope at pushing impact damper place and the angle of shovel bar respectively, F " ₃shovel when bar is withdrawn from from ore body with pressure measured by the tension pick-up be arranged between arm carrier and pushing wire rope;

9) push wire rope by following formulae discovery and act on pushing pulley lifting force F ₂arm of force D ₂impact damper lifting force F is pushed with acting on ₃arm of force D ₃,

D ₂＝y ₂ (16)

D ₃＝y ₃ (17)

10) according to the quality of shovel stick force square EQUILIBRIUM CALCULATION FOR PROCESS material,

$M=\frac{F_1\×D_1+(1-s)\×F_3\×D_3-s\×F_2\×D_2-G_1\×x_1^{\′}}{x_0^{\′}\×g}---\left(18\right)$

In formula (18), G ₁be shovel bar and be attached to the integrant gravity of shovel bar upper-part, g is that acceleration of gravity gets 9.8N/m ², s is a coefficient, and when shovel bar advances to ore body, s equals 1, and when shoveling bar and withdrawing from from ore body, s equals 0.

2. electric excavator Weighing method according to claim 1, is characterized in that: the beginning in 0.3 to 0.7 second after turning course starts of weighing of described electric excavator.

3. electric excavator Weighing method according to claim 1 and 2, characterized by further comprising the step of weighing results screening, the full bucket material mass value Mn of setting power shovel, when weighing results M is less than 5% of Mn or be greater than 120% of Mn, then this result of weighing, refuses value not in the reasonable scope; Be greater than 5% of Mn as weighing results M and be less than 120% of Mn, then this result of weighing, gives value in the reasonable scope.