WO2014166331A1

WO2014166331A1 - Stability monitoring system and excavator

Info

Publication number: WO2014166331A1
Application number: PCT/CN2014/073920
Authority: WO
Inventors: 曹东辉; 杨洪波; 徐瑾; 杨俊�
Original assignee: 三一重机有限公司; 上海华兴数字科技有限公司
Priority date: 2013-04-09
Filing date: 2014-03-24
Publication date: 2014-10-16
Also published as: CN103234701B; CN103234701A

Abstract

A stability monitoring system comprising several force measuring apparatus (1), a processor (2), and a controller (3). The several force measuring apparatus (1) are arranged on the inner circumference of a base (5) of a slewing bearing (4) of an excavator and are uniformly distributed on the inner circumference of the base (5). The force measuring apparatus (1) are connected to the controller (3) via the processor (2). The stability monitoring system is an excavator overall stability real-time monitoring system that is highly integrated, is simple and easy, covers a wide range of working conditions, and allows for implementation of functions such as excavator inclination angle monitoring, real-time monitoring of bending moments that the excavator is subjected to in various working conditions, excavator operating direction identification, and critical tipping bending moment auxiliary control. Also provided is the excavator comprising the monitoring system.

Description

A stability monitoring system and an excavator. This application claims priority to Chinese Patent Application No. 201310122358.7, entitled "A Stability Monitoring System and Excavator", submitted to the China Patent Office on April 9, 2013. The entire contents of which are incorporated herein by reference. Technical field

The invention belongs to the field of engineering machinery monitoring, and relates to a monitoring system, in particular to a stability monitoring system and an excavator including the same. Background technique

The excavator is a multi-purpose earthwork construction machine. It mainly excavates and loads earth and stone, and can also carry out land leveling, slope repairing and hoisting operations, road construction, bridge construction, urban construction, airport port and water conservancy construction. It is widely used. The environment in which the excavator is operating is complex and variable. The excavator needs to constantly move with the change of working conditions and the attitude adjustment of the whole machine. The operational safety depends largely on the driver's driving experience. When the working platform of the excavator has a large slope, the load bearing platform is soft and easy to collapse, the roadway has a large ups and downs, or when the lifting operation is performed, the excavator is easy to be unstable. If the operator does not handle it properly, the excavator will fall. Serious consequences of turning over.

Traditional methods for improving operational safety include: 1. Increasing the weight, widening the track shoes, and improving the stability of the machine; 2. Using a larger vision cab and installing a rear camera to improve the driver's observation. 3. The ability to detect the stability of the excavator with various real-time monitoring equipment, feedback to the driver after processing the signal, and automatically control the whole machine if necessary.

Prior to the invention of the present invention, the inventors of the present invention found that the prior art has the following problems: The method of improving the stability of the whole machine to improve the stability has certain limitations, and cannot be reformed without an upper limit; the weight is increased, and the crawler is widened. The role of measures such as boards is limited. And use larger view The wild cab, the installation of the rear camera and other measures are only intended to enhance the driver's perception, and still have a large dependence on the driver's operating level, and the durability of the attachment is not good. Summary of the invention

In view of this, the present invention provides a real-time monitoring system for the stability of an excavator with small changes, high system integration, simple and easy operation, and wide working conditions, which can realize the inclination monitoring of the excavator and the excavator work. Under the condition of real-time monitoring of bending moment, identification of excavator running direction, and auxiliary control of critical tipping moment.

In order to achieve the above objectives, the specific technical solutions are as follows:

In one aspect, the present invention provides a stability monitoring system for monitoring an excavator, including a plurality of force measuring devices, a processor, and a controller, wherein the plurality of force measuring devices are disposed on an inner circumference of a base of the slewing bearing of the excavator. And the hooks are distributed on the inner circumference of the base, and the force measuring device is configured to monitor the force of the inner circumference of the base, and the force measuring device is connected to the controller through the processor.

Preferably, a tilt sensor for monitoring the tilt of the excavator is further provided, the tilt sensor is disposed on a lower frame of the excavator, and the tilt sensor is connected to the controller through the processor.

Preferably, the method further comprises transmitting a signal generated by the force measuring device to a signal transmission unit of the processor, wherein the force measuring device is connected to the processor through a signal transmission unit.

Preferably, the number of the force measuring devices is four.

Preferably, the signal transmission unit is a frequency division multi-channel remote sensing device.

Preferably, the four force measuring devices are all distributed on the base at positions corresponding to the front, rear, left and right directions of the walking direction of the excavator.

Preferably, the force measuring device comprises a hollow circular section rod vertically disposed on an inner circumference of the base, and a plurality of strain gauges uniformly disposed on an outer circumference of the hollow circular section rod.

Preferably, the force measuring device further comprises a connecting plate and a fastening bolt, and the connecting plate and the connecting plate One end of the force measuring device is connected to the base, and the other end of the force measuring device is connected to the connecting plate by the fastening bolt.

Preferably, the strain gauge comprises a first set of strain gauges and a second set of strain gauges, wherein the first set and the second set of strain gauges respectively comprise two strain gauges distributed along the longitudinal direction of the hollow circular section rod and two The transversely distributed strain gauges have a total of 8 strain gauges, and the 8 strain gauges are connected to a DC full-bridge circuit to detect strain, and the longitudinally distributed strain gauges in the first and second sets of strain gauges and the transversely distributed strain The sheets are sequentially connected in series to form a half bridge.

In another aspect, the invention also provides an excavator comprising a monitoring system as described above. Compared with the prior art, the present invention has the following advantages:

1. The system structure is simple, and the integration of measurement, signal transmission, signal processing and feedback is high;

2. 8 Use 8 strain gauges to form a full bridge to measure strain, and the system accuracy is high;

3, compact structure, easy to install and change with the design changes.

4. The overall installation is convenient, the structure is reasonable, the degree of automation is high, and the applicability is wide. DRAWINGS

Figure 1 is a system block diagram of an embodiment of the present invention;

2 is a schematic view of an excavator according to an embodiment of the present invention;

Figure 3 is a schematic view of a base of an embodiment of the present invention;

Figure 4 is a schematic view of a force measuring device of an embodiment of the present invention;

Figure 5 is a schematic view showing the wiring of the force measuring device of the embodiment of the present invention;

Figure 6 is a graph showing changes in stress of an embodiment of the present invention;

Fig. 7 is a view showing a position of a strain gauge corresponding to a wiring diagram of a force measuring device according to an embodiment of the present invention.

Among them, 1 is the force measuring device, 2 is the processor, 3 is the controller, 4 is the slewing bearing, 5 is the base, 6 is the inclination sensor, 7 is the hollow circular section rod, 8 is the strain gauge, 9 is the connecting plate, 10 To tighten the bolts. detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, but not all embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

It should be noted that the embodiments of the present invention and the features of the embodiments may be combined with each other without conflict.

The embodiments of the present invention will be specifically explained below in conjunction with the accompanying drawings.

An excavator stability monitoring system of the embodiment of the invention as shown in Fig. 1 is intended to monitor an excavator, comprising a plurality of force measuring devices 1, a processor 2 and a controller 3. As shown in Figs. 2 and 3, the force measuring device 1 is provided on the inner circumference of the base 5 of the slewing ring 4 of the excavator. As shown in Fig. 3, a plurality of force measuring devices 1 are evenly distributed on the inner circumference of the base 5. As shown in Fig. 1, the force measuring device 1 is connected to the controller 3 via the processor 2.

The embodiment of the present invention measures the magnitude of the pressure received by the excavator base in the direction of the force measuring device by the force measuring device disposed on the excavator base 5, and the signals are summarized and processed by the processor 2, and then transmitted to the location. The controller of the cab 3. Therefore, according to the calculated steering of the upper part of the excavator relative to the lower frame, and the bending moment of the upper part of the excavator base, the whole working condition of the excavator is obtained, and the dangerous point is judged. When the danger may occur, the controller 3 makes a warning signal; when the danger is about to occur, the controller 3 assists the whole machine to control.

The embodiment of the invention has high system integration, simple and easy operation, and covers the real-time monitoring system of the whole machine stability of the excavator, which can realize the inclination monitoring of the excavator and the real-time monitoring of the bending moment of the excavator under various working conditions. Preferably, the operation direction identification of the excavator, the critical tilting moment assist control, and the like are preferred, and the force measuring device 1 can employ a pressure sensor, and the number of the force measuring device 1 can be set. Preferably, the four force measuring devices 1 can be uniformly distributed in the front, rear, left and right directions of the excavator traveling direction, that is, the longitudinal direction of the excavator lower frame is set to a right angle from the forward direction to the coordinate system X positive direction. Coordinate System.

As shown in Fig. 4, in the embodiment of the present invention, the force measuring device 1 comprises a hollow circular section rod 7 vertically disposed on the inner circumference of the base, and a plurality of strain gauges 8 uniformly disposed on the outer circumference of the hollow circular section rod 7.

8 strain gauges 8 of the same specification are evenly attached around the hollow circular section rod 7, and the strain gauges 8 are arranged longitudinally four, four in the transverse direction, and the hollow circular section rods 7 are used to reduce the additional sensor structure to the original The effect of the actual stress of the structure. The actual resistance of the eight strain gauges 8 is represented by R1 R8, and the initial values are the same. The wiring is shown in Figure 5. The measuring circuit is connected to the DC full-bridge circuit by the eight strain gauges to detect strain. Each bridge arm is longitudinally along the rod. The two strain gauges opposite to each other are connected in series. The force measuring device 1 further comprises a connecting plate 9 and a fastening bolt 10, the two connecting plates 9 are fixedly connected with the base 5, and the hollow circular section rod 7 of the force measuring device 1 is placed in the middle of the two connecting plates 9, by fastening bolts The pressing pad applies a pre-tightening force to the hollow circular section bar 7 to adjust the initial state of measurement of the force measuring device 1. The deformation caused by the longitudinal force of the excavator base 5 causes the relative position of the two connecting plates 9 to change. By measuring the strain of the hollow circular section rod 7 on the force measuring device 1, the equivalent excavator base 5 is between the two connecting plates 9. The average strain, which in turn leads to the stress state there.

As shown in FIG. 4, FIG. 5 and FIG. 7, the strain gauge comprises a first set of strain gauges and a second set of strain gauges, and the first set of strain gauges comprises two strain gauges R1, R3 distributed along the longitudinal direction of the hollow circular section rods. And two laterally distributed strain gauges R6, R8, and respectively form a bridge arm I and a bridge arm II; the second set of strain gauges comprises two strain gauges R2, R4 and two transverse distributions distributed along the longitudinal section of the hollow circular section rod The strain gauges R5 and R7 form the bridge arm ΠΙ and the bridge arm IV respectively; the bridge arm I is adjacent to the bridge arms II and IV, and is opposite to the bridge arm III. The strain gauges in the first group and the second group of strain gauges are respectively The half bridge is formed in series, and the eight strain gauges are connected into a DC current strain full bridge. The difference between the output voltage of the strain bridge and the rate of change of the resistance of the adjacent arms, or proportional to the sum of the rate of change of the resistance of the two arms. When the four arms of the bridge are connected to the same strain gauge, there are:

ΚΕ _η , , In the structure of the force measuring device 1, for a single strain gauge, there are three factors that affect the change of resistance: first, longitudinal average stress; second longitudinal offset equivalent bending moment produces additional stress Third temperature effect. The first influencing factor has an effect on all longitudinal strain gauges, and the effect on all transverse strain gauges is R. The second influencing factor produces equal, positive and negative resistance changes for all strain gauges that are symmetric along the longitudinal section of the hollow circular section rod. The third influencing factor has the same effect on all strain gauge resistance. For the bridge arm I, its resistance change rate ^ is:

In this formula, the longitudinal average stress is equal to p: the longitudinal eccentric equivalent bending moment M,

Two sizes are equal, square

Under the influence of temperature changes,

Two equal

This extends to the full bridge, and the effects of the equivalent bending moment and temperature change of the eccentric load are eliminated by each other; the initial resistance is equal to R1=R2= ... =R8 ; the influence of the longitudinal average stress

p, after derivation calculation, output voltage:

Where ~ is the resistance change rate of the four bridge arms, K is the strain gauge sensitivity coefficient, E0 is the constant input voltage of the bridge, and the longitudinal strain value generated by the load cell 1 transmitting the longitudinal pressure of the base 5, μ is a hollow circular section The Poisson's ratio of the material of the rod 7 and the strain value measured by the horizontal transverse strain gauge are -μ times the longitudinal strain.

In the structure of the force measuring device 1, two strain gauges connected in series with the same bridge arm eliminate the influence of load eccentricity; the strain gauges are arranged horizontally and vertically in the series pair and then adjacent to the adjacent half bridge, which can compensate for temperature effects and make relative The result is larger than the single strain gauge ( l + μ ) times; the full bridge method is used to double the above voltage output.

In an embodiment of the invention, a signal transmission unit is further included, and the force measuring device 1 is connected to the processor 2 via a signal transmission unit. Preferably, the signal transmission unit is a frequency division multi-channel remote sensing device. The frequency division multi-channel remote sensing device comprises a transmitter and a receiver, the transmitter comprises an amplifier, a subcarrier generator, a modulator, a high frequency oscillator; the receiver comprises an amplifier, a demodulator, a filter, a subcarrier demodulator.

The electric signal outputted by the measuring circuit of the force measuring device 1 is amplified by the amplifier and sent to the subcarrier generator, and the carrier is modulated. The center frequency of each carrier is different, and the modulated carriers are mixed and modulated. The main carrier of the frequency oscillator is then transmitted by the antenna in the form of electromagnetic waves. The receiver amplifies and demodulates the received main carrier and sends it to each bandpass filter. The passband corresponds to the carrier center frequency of each transmitter, and the subcarrier filtered out by each filter is sent to the carrier solution. The modulator obtains an electrical signal similar to the original signal, amplifies it and sends it to the processor 2, and obtains the strain value of each measuring circuit after the multiple operation, and then calculates the corresponding stress value σ 1~ σ 4 .

σ _ι + σ ₂ + σ ₃ + σ ₄

Processor 2 further calculates the average stress of the base: ° ⁴ The weight of the base that bears the upper part of the vehicle is: ^G i ^=cr o' ^S ^S is the annular cross-sectional area of the base. The difference between the four stresses and the average stress is: ^Acr i ^=cr i- ^σ ο ^{i = 1} ~ ⁴ As shown in Figure 6, after the four stresses remove the average stress, it can be regarded as the rotation of the base stress plane around the center of the circle. The axis is inverted by a certain angle α, and the rotation axis 成 is at an angle m to the following coordinate system, and the inner diameter of the base is R, which is obtained by geometric relationship:

Ασ _ι - c tan = R- sin m . Δσ ₂ .ctan = R.cosm

Δσ,

Tan m = ^L

Available:

The relative rotation angle between the front and rear direction of the upper frame and the lower frame, that is, the angle between the front of the driver and the direction of the chassis of the excavator is: π

η = arc tan m

2 tan a = ― tana = ² can also get the stress plane tilt angle: Rsinm, (or: Rcosm, correct the front formula under the angle limit state).

Base 5 is based on the average stress level in the stress plane, and the maximum stress change is:

Aa _m = Rtainr Base maximum stress value: ^= +A _m = _{0 +} Rt _a n The bending moment of the base is: ^M

w

D is the bending section modulus of the circular section of the base 5.

That is, the four stress values measured by the force measuring device 1 calculate the rotation angle of the frame on the excavator relative to the lower frame, thereby judging the traveling direction of the excavator and the overall pair of the boarding portion. The bending moment of the base 5. In general, the front side of the upper frame (the side of the working device) and the rear side (the weight side) have a large effect on the bending moment of the slewing support 4, and in special cases, when the excavator bucket supports the ground or the digging action cuts into the hard material, Due to the greater influence of the ground on the upward force of the bucket, the bending moment of the lower frame base 5 is opposite, that is, the rotation angle calculated above needs to be increased by 180°, which can be directly judged by the driver.

As shown in Fig. 1, in the embodiment of the present invention, it is preferable to further include a tilt sensor 6, the tilt sensor is disposed on the lower frame of the excavator, and the tilt sensor 6 is connected to the controller 3 through the processor 2.

The inclination of the excavator is measured by the inclination sensor 6 disposed on the lower frame, and the real-time working condition of the excavator is obtained by combining the rotation angle of the upper part of the vehicle with the bending moment formed. For the fixed excavator model, there is a fixed center of gravity and a fixed tilting line in all directions. From the above-mentioned inclination angle, the center of gravity of the lower frame against the tilting line is calculated. Combining the gravity and bending moment values of the upper part of the vehicle calculated by the data of the load cell 1 of the base 5, the real-time stability of the excavator is calculated.

When the excavator is in a steady state, the stabilizing torque is greater than the tipping moment, and there are:

G ₁ L ₁ +G ₂ L^ > k M , ^ are the force arm of the upper part of the gravity value Gi and the lower part of the gravity value ⁶² on the tilting line, respectively, and the arm is adjusted as the tilt angle of the excavator is changed. The value is specifically the ^CQ times of the force arm value when the whole machine is placed horizontally; ^k is the safety factor; M is the bending moment value of the upper part to the base.

Preferably, the controller 3 is provided with a display, and the real-time working condition of the excavator can be checked on the display, including the inclination angle of the whole machine, the rotation angle of the upper frame relative to the lower frame (the direction of the excavator), and the tilting moment of the upper frame. And preferably, the controller 3 is provided with an alarm device, when the upper type stable torque is less than

1.2 times the roll moment ^(k = l. ^2), the controller 3 controls the whole audible warning signal. when When the stabilizing torque is less than 1.1 times the tilting moment ( ^{k = L 1} ), the controller 3 controls the excavator to perform the operation of reducing the tilting moment to realize the automatic hedging function. The controller 3 is also provided with a lock switch, and the controller 3 can turn off the automatic control function by releasing the lock switch.

The embodiment of the present invention further includes an excavator, wherein the monitoring system is provided. Since the monitoring system has the above technical effects, the excavator provided with the monitoring system should also have corresponding technical effects, and the specific The implementation process is similar to the above embodiment, and will not be described again.

The specific embodiments of the present invention have been described in detail above, but by way of example only, the invention is not limited to the specific embodiments described above. Any equivalent modifications and substitutions to the invention are also within the scope of the invention. Therefore, equivalent changes and modifications may be made without departing from the spirit and scope of the invention. Industrial applicability

The stability monitoring system provided by the invention has high integration degree, and can realize the functions such as the inclination monitoring of the excavator, the real-time monitoring of the bending moment under the working conditions of the excavator, the identification of the running direction of the excavator, and the auxiliary control of the critical tilting moment. Therefore, the present invention has industrial applicability.

Claims

claims

1. A stability monitoring system for monitoring excavators, characterized in that it includes a number of force measuring devices, a processor and a controller, and a number of the force measuring devices are located on the inner circumference of the base of the slewing support of the excavator, And evenly distributed on the inner circumference of the base, the force measuring device is used to monitor the pressure on the inner circumference of the base, and the force measuring device is connected to the controller through the processor.

2. The monitoring system according to claim 1, further comprising an inclination sensor for monitoring the inclination of the excavator, the inclination sensor being arranged on the lower frame of the excavator, and the inclination sensor passing through The processor is connected to the controller.

3. The monitoring system according to claim 1, further comprising a signal transmission unit that transmits the signal generated by the force measuring device to the processor, and the force measuring device is connected to the processor through the signal transmission unit.

4. The monitoring system according to claim 1, characterized in that the number of said force measuring devices is four.

5. The monitoring system according to claim 3, characterized in that the signal transmission unit is a frequency division multi-channel remote sensing device.

6. The monitoring system according to claim 4, characterized in that the four force measuring devices are evenly distributed on the base at positions corresponding to the front, rear, left and right directions of the excavator's traveling direction. superior.

7. The monitoring system according to any one of claims 1 to 6, characterized in that the force measuring device includes a hollow circular cross-section rod arranged vertically on the inner circumference of the base, and several rods are hooked on the hollow Strain gauges on the outer circumference of a circular cross-section rod.

8. The monitoring system according to claim 7, wherein the force measuring device further includes a connecting plate and a fastening bolt, the connecting plate is connected to the base, and one end of the force measuring device is connected to the base. The base is connected, and the other end of the force measuring device is connected to the connection through the fastening bolt. Board connection.

9. The monitoring system according to claim 7, wherein the strain gauges include a first group of strain gauges and a second group of strain gauges, and each of the first group and the second group of strain gauges respectively includes two edges. The longitudinally distributed strain gauges and two transversely distributed strain gauges of the hollow circular cross-section rod total 8 strain gauges. The 8 strain gauges are connected into a DC full-bridge circuit to detect strain, and the first group and the second group of strain gauges are The longitudinally distributed strain gauges and transversely distributed strain gauges in the piece are connected in series to form a half-bridge.

10. An excavator, characterized by including the monitoring system according to any one of claims 1 to 9.