Roll-over evaluation system, roll-over evaluation method, and working machine

Abstract

The energy calculation section calculates, for each of a plurality of sides of a support polygon of the work machine, energy required for the work machine to overturn with the side as a rotation axis. The evaluation section evaluates the possibility of overturning of the work machine on the basis of the calculated energy for each side.

Description

Technical Field

[0001] This disclosure relates to a rollover assessment system, a rollover assessment method, and the machinery used for such assessments.

[0002] This application claims priority to Japanese Patent Application No. 2021-036156, filed on March 8, 2021, the contents of which are incorporated herein by reference. Background Technology

[0003] Patent Document 1 discloses a technique for calculating the ZMP (Zero Moment Point) of a working machine and informing the operator of information related to the possibility of tipping over. ZMP refers to the point where the torque in the pitch and roll directions is zero. It is known that when the ZMP exists on or inside the side of a support polygon that connects the working machine and the grounding point in a manner that does not form a recess, the working machine is stably grounded.

[0004] Prior art literature

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 2011 / 148946 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] The calculation method described in Patent Document 1 may determine a high probability of tipping over when the machine is lifted due to its own inertial force. Therefore, sometimes a method using energy stability margin to evaluate the probability of tipping over is used instead of ZMP. Energy stability margin refers to the energy required to tip over in a certain posture.

[0009] However, in operating machinery, the supporting polygon sometimes changes depending on the operating conditions. For example, in a hydraulic excavator, the upper slewing body rotates relative to the lower traveling body, so the position of the center of gravity relative to the supporting polygon changes with rotation.

[0010] The purpose of this disclosure is to provide a tipping evaluation system, tipping evaluation method, and work machinery that can evaluate the likelihood of tipping over based on the relationship between the rotational motion and the tipping direction.

[0011] Solution for solving the problem

[0012] According to a first aspect of the present invention, the overturning evaluation system is an overturning evaluation system for a work machine having a working device, wherein the overturning evaluation system includes a processor, the processor including: an energy calculation unit that calculates the energy required for the work machine to overturn with the work machine rotating around a plurality of sides of a support polygon of the work machine; and an evaluation unit that evaluates the likelihood of the work machine overturning based on the calculated energy for each of the sides.

[0013] According to a second aspect of the present invention, the overturning evaluation method includes: the steps of calculating the energy required for the working machine to overturn with the side as the rotation axis for each of the multiple sides of the supporting polygon of the working machine having the working device; and the steps of evaluating the likelihood of the working machine overturning based on the calculated energy for each of the sides.

[0014] According to a third aspect of the present invention, a working machine includes: a traveling body; a rotating body supported on the traveling body in a rotatable manner; a working device mounted on the rotating body; and a processor, the processor including: a center of gravity position calculation unit that calculates the center of gravity position of the working machine; an energy calculation unit that calculates, based on the center of gravity position of the working machine, the energy required for the working machine to tip over with the supporting polygon of the traveling body as a rotation axis around each of the sides; and an evaluation unit that evaluates the likelihood of the working machine tipping over based on the calculated energy for each of the sides.

[0015] Invention Effects

[0016] According to the above scheme, the likelihood of the working machine tipping over can be evaluated based on the relationship between the rotation action and the tipping direction. Attached Figure Description

[0017] Figure 1 This is a schematic diagram showing the structure of the working machine according to the first embodiment.

[0018] Figure 2 This is a schematic block diagram showing the structure of the control device according to the first embodiment.

[0019] Figure 3 It is a diagram used to illustrate the energy stability margin.

[0020] Figure 4 It is a diagram showing the relationship between the energy stability margin and the position of the center of gravity.

[0021] Figure 5 This is a diagram illustrating an example of a sign indicating the risk of tipping over in the first embodiment.

[0022] Figure 6This is a flowchart illustrating the operation of the control device according to the first embodiment.

[0023] Figure 7 This is a schematic block diagram showing the structure of the control device according to the second embodiment. Detailed Implementation

[0024] <First Implementation Method>

[0025] Structure of Operation Machinery 100

[0026] The following is a reference to the appendix. Figure 1 The implementation method will be described in detail below.

[0027] Figure 1 This is a schematic diagram showing the structure of the working machine according to the first embodiment. The working machine of the first embodiment is, for example, a hydraulic excavator. The working machine 100 includes a traveling body 110, a slewing body 130, a working device 150, a cab 170, and a control device 190.

[0028] The traveling body 110 supports the work machine 100 so that it can move. The traveling body 110 is, for example, a pair of tracks, left and right. The pair of tracks are parallel to and linearly symmetrical with respect to a straight line extending in the direction of travel. Therefore, in the first embodiment, the supporting polygon represented by the convex hull involving the contact point of the traveling body 110 is a rectangle. The convex hull is the smallest convex polygon that contains all specific points. The specific points are, for example, the points where the tracks contact the ground. Hereinafter, the convex hull involving the contact point of the traveling body 110, i.e., the rectangle, will be referred to as the supporting rectangle R.

[0029] The rotating body 130 is supported on the traveling body 110 in a manner that allows it to rotate around the center of rotation.

[0030] The working device 150 is supported on the front of the rotary body 130 in a manner that allows it to be driven vertically. The working device 150 is hydraulically driven. The working device 150 includes a boom 151, a stick 152, and a bucket 153. The base end of the boom 151 is rotatably mounted to the rotary body 130. The base end of the stick 152 is rotatably mounted to the front end of the boom 151. The base end of the bucket 153 is rotatably mounted to the front end of the stick 152. Here, the portion of the rotary body 130 on which the working device 150 is mounted is referred to as the front portion. Furthermore, regarding the rotary body 130, based on the front portion, the portion opposite is referred to as the rear portion, the left portion as the left portion, and the right portion as the right portion.

[0031] The cab 170 is located at the front of the slewing body 130. The cab 170 is equipped with operating devices for the operator to operate the machinery 100, and an alarm device to inform the operator of the risk of tipping over. In the first embodiment, the alarm device informs of the risk of tipping over via a loudspeaker and a display device.

[0032] The control device 190 controls the traveling body 110, the rotating body 130, and the working device 150 based on the operator's operation of the operating device. The control device 190 is, for example, located inside the cab 170.

[0033] The working machine 100 is equipped with multiple sensors for detecting the working status of the working machine 100. Specifically, the working machine 100 is equipped with a tilt detector 101, a slewing angle sensor 102, a boom angle sensor 103, a stick angle sensor 104, a bucket angle sensor 105, and a load cell 106.

[0034] The tilt detector 101 measures the acceleration and angular velocity of the rotating body 130, and detects the tilt of the rotating body 130 relative to the horizontal plane (e.g., roll angle and pitch angle) based on the measurement results. The tilt detector 101 is, for example, located below the cab 170. As an example of the tilt detector 101, an IMU (Inertial Measurement Unit) can be cited.

[0035] The slewing angle sensor 102 is located at the center of rotation of the rotating body 130 and detects the slewing angle between the traveling body 110 and the rotating body 130. The measured value of the slewing angle sensor 102 is zero when the traveling body 110 and the rotating body 130 are in the same direction.

[0036] The boom angle sensor 103 detects the rotation angle of the boom 151 relative to the slewing body 130, i.e., the boom angle. The boom angle sensor 103 can be an IMU mounted on the boom 151. In this case, the boom angle sensor 103 detects the boom angle based on the tilt of the boom 151 relative to the horizontal plane and the tilt of the slewing body measured by the tilt detector 101. The measured value of the boom angle sensor 103 is zero when the direction of the straight line passing through the base and tip of the boom 151 is consistent with the forward / backward direction of the slewing body 130. It should be noted that in other embodiments, the boom angle sensor 103 can also be a stroke sensor mounted on the boom cylinder. Additionally, in other embodiments, the boom angle sensor 103 can also be an angle sensor disposed on the pin connecting the slewing body 130 and the boom 151.

[0037] The stick angle sensor 104 detects the rotation angle of the stick 152 relative to the boom 151, i.e., the stick angle. The stick angle sensor 104 can be an IMU mounted on the stick 152. In this case, the stick angle sensor 104 detects the stick angle based on the tilt of the stick 152 relative to the horizontal plane and the boom angle measured by the boom angle sensor 103. The measured value of the stick angle sensor 104 is zero when the direction of the straight line passing through the base and tip of the stick 152 is consistent with the direction of the straight line passing through the base and tip of the boom 151. It should be noted that in other embodiments, the stick angle sensor 104 can also use a stroke sensor mounted on the stick cylinder for angle calculation. The stick angle sensor 104 can also be a rotation sensor located on the pin connecting the boom 151 and the stick 152.

[0038] The bucket angle sensor 105 detects the rotation angle of the bucket 153 relative to the stick 152, i.e., the bucket angle. It can also be a stroke sensor installed in the bucket cylinder used to drive the bucket 153. In this case, the bucket angle sensor 105 detects the bucket angle based on the stroke of the bucket cylinder. The measured value of the bucket angle sensor 105 is zero when the direction of the straight line passing through the base and tip of the bucket 153 is consistent with the direction of the straight line passing through the base and tip of the stick 152. It should be noted that in other embodiments, the bucket angle sensor 105 can also be an angle sensor installed on the pin connecting the stick 152 and the bucket 153. Additionally, in other embodiments, the bucket angle sensor 105 can also be an IMU mounted on the bucket 153.

[0039] The load cell 106 measures the weight of the load held in the bucket 153. For example, the load cell 106 measures the bottom pressure of the cylinder of the boom 151 and converts it into the weight of the load. Alternatively, the load cell 106 could also be a force sensor.

[0040] Structure of Control Device 190

[0041] Figure 2 This is a schematic block diagram showing the structure of the control device 190 according to the first embodiment.

[0042] The control device 190 is a computer equipped with a processor 210, a main memory 230, a storage device 250, and an interface 270.

[0043] Storage 250 is a non-volatile tangible storage medium. Examples of storage 250 include magnetic disks, optical disks, optical discs, and semiconductor memories. Storage 250 can be an internal medium directly connected to the bus of control device 190, or an external medium connected to control device 190 via interface 270 or a communication line. Storage 250 stores programs for controlling the machine 100.

[0044] The program can be a part of the program used to implement the functions of the control device 190. For example, the program can also function by combining with other programs already stored in the memory 250 or with other programs installed on other devices. It should be noted that in other embodiments, the control device 190 may also have a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to or replacing the above-described structure. Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). In this case, part or all of the functions implemented by the processor may also be implemented by the integrated circuit.

[0045] The storage device 250 records geometric data representing the dimensions and center of gravity positions of the traveling body 110, rotating body 130, boom 151, stick 152, and bucket 153, as well as the weights of the traveling body 110, rotating body 130, boom 151, stick 152, and bucket 153. The geometric data represents the position of an object in a defined coordinate system. The coordinate system in the first embodiment includes a world coordinate system and a local coordinate system. The world coordinate system is formed by the Z-axis extending vertically. w axis and Z w orthogonal X-axis w Axis and Y w An orthogonal coordinate system represented by axes. A local coordinate system is an orthogonal coordinate system with a reference point of a certain object as its origin.

[0046] The geometric data of the vehicle 110 represents the position of the center of gravity (x) of the vehicle 110 in the vehicle coordinate system, which is the local coordinate system. tb＿com y tb＿com z tb＿com The coordinate system includes the track length L, width w, and height h. The traveling body coordinate system is based on the rotation center of the traveling body 110, and extends along the X-axis in the front-rear direction. tb Axis, Y extending in the left-right direction tb Axis, Z extending in the vertical direction tb A coordinate system formed by axes.

[0047] The geometric data of the rotating body 130 represent the position (x) of the pin of the supporting arm 151 of the rotating body 130 in the rotating body coordinate system, which is the local coordinate system. bm y bm zbm The position of the origin of the driving body coordinate system (x) tb y tb z tb ) and the position of the center of gravity of the rotating body 130 (x sb＿com y sb＿com z sb＿com The coordinate system of the rotating body is based on the center of rotation of the rotating body 130, and extends along the X-axis in the front-rear direction. sb Axis, Y extending in the left-right direction sb Axis, Z extending in the vertical direction sb A coordinate system formed by axes.

[0048] The geometric data of boom 151 represents the position (x) of the support stick 152 pin in the boom coordinate system, which is the local coordinate system. am y am z am ) and the center of gravity position (x) of boom 151 bm＿com y bm＿com z bm＿com The boom coordinate system is based on the position of the pin connecting the boom 151 and the rotating body 130, and extends along the length direction from the X-axis. bm Y-axis extending along the direction of the pin bm Axis, and X bm axis and Y bm Z-axis orthogonal bm A coordinate system formed by axes.

[0049] The geometric data of the boom 152 represents the position (x) of the pin supporting the bucket 153 in the boom coordinate system, which is the local coordinate system. bk y bk z bk ) and the center of gravity position (x) of pole 152. am＿com y am＿com z am＿com The stick coordinate system is based on the position of the pin connecting the stick 152 and the boom 151, and extends along the length direction by the X-axis. am Y-axis extending along the direction of the pin am Axis, and X am axis and Y am Z-axis orthogonal am A coordinate system formed by axes.

[0050] The geometric data of bucket 153 represents the position of the bucket tip (x) in the bucket coordinate system, which is the local coordinate system. ed y ed z ed ), the center of gravity position of bucket 153 (x bk＿com y bk＿comz bk＿com ) and the center of gravity (x) of the load pl＿com y pl＿com z pl＿com The bucket coordinate system is based on the position of the pin connecting the bucket 153 and the stick 152, and extends along the X-axis in the direction of the bucket tip. bk Y-axis extending along the direction of the pin bk Axis, and X bk axis and Y bk Z-axis orthogonal bk A coordinate system formed by axes.

[0051] Software Structure

[0052] The processor 210 performs its functions as an acquisition unit 211, a position determination unit 212, a center of gravity calculation unit 213, an energy calculation unit 214, a normalization unit 215, an evaluation unit 216, and an output unit 217 by executing a program.

[0053] The acquisition unit 211 acquires measurement values ​​from the tilt detector 101, the slewing angle sensor 102, the boom angle sensor 103, the stick angle sensor 104, the bucket angle sensor 105, and the load cell 106, respectively.

[0054] The position determination unit 212 determines the center of gravity position of each part of the working machine 100 based on various measurement values ​​obtained by the acquisition unit 211 and geometric data recorded in the storage unit 250. Specifically, the position determination unit 212 determines the center of gravity position of the traveling body 110, the slewing body 130, the boom 151, the stick 152, the bucket 153, and the load in the world coordinate system in the following order.

[0055] The position determination unit 212 determines the position based on the pitch angle θ obtained by the acquisition unit 211. p and the roll angle θ r The measured values ​​are used to generate the rotation-world transformation matrix T for transforming from the rotation coordinate system to the world coordinate system using the following equation (1). sb w Rotational body-world transformation matrix T sb w By around Y sb Axis rotation pitch angle θ p The rotation matrix and the rotation around X sb Shaft rotation tilt angle θ r It is represented by the product of the rotation matrices.

[0056] [Mathematical Formula 1]

[0057]

[0058] The position determination unit 212 determines the position based on the rotation angle θ between the traveling body 110 and the rotating body 130 obtained by the acquisition unit 211. s The measured values ​​and geometric data of the rotating body 130 are used to generate the driving-rotating body transformation matrix T for transformation from the driving body coordinate system to the rotating body coordinate system using the following equation (2). tb sb Transformation matrix T between moving body and rotating body tb sb It is to make Z-shaped tb Axis rotation pitch angle θ p Furthermore, the deviation (x) between the origin of the parallel translation rotation coordinate system and the origin of the driving coordinate system tb y tb z tb The matrix of ) is used. Additionally, the position determination unit 212 calculates the revolution-world transformation matrix T. sb w Transformation matrix T between moving body and rotating body tb sb The product of these components generates the vehicle-to-world transformation matrix T, used for transforming from the vehicle coordinate system to the world coordinate system. tb w .

[0059] [Mathematical Formula 2]

[0060]

[0061] The position determination unit 212 determines the boom angle θ obtained by the acquisition unit 211. bm The measured values ​​and geometric data of the slewing body 130 are used to generate the boom-slewing body transformation matrix T for transformation from the boom coordinate system to the slewing body coordinate system using the following equation (3). bm sb Boom-rotor transformation matrix T bm sb It is to make Y-shaped bm Axis rotation boom angle θ bm Furthermore, the deviation (x) between the origin of the parallel translation rotary coordinate system and the origin of the boom coordinate system bm y bm z bm The matrix of ) is used. Additionally, the position determination unit 212 calculates the revolution-world transformation matrix T. sb w With boom-rotor transformation matrix T bm sb The product of these components generates the stick-world transformation matrix T, used for transforming from the boom coordinate system to the world coordinate system. bm w .

[0062] [Mathematical Formula 3]

[0063]

[0064] The position determination unit 212 is based on the stick angle θ obtained by the acquisition unit 211. am The measured values ​​and geometric data of boom 151 are used to generate the stick-boom transformation matrix T for transformation from the stick coordinate system to the boom coordinate system using the following equation (4). am bm boom-stick conversion matrix T am bm It is to make Y-shaped am Axis rotation boom angle θ am Furthermore, the deviation (x) between the origin of the parallel movement boom coordinate system and the origin of the stick coordinate system am y am z am The matrix is ​​used to determine the position. Additionally, the position determination unit 212 calculates the stick-world transformation matrix T. bm w With the stick-boom conversion matrix T am bm The product of these components generates the stick-world transformation matrix T, used for transforming from the stick coordinate system to the world coordinate system. am w .

[0065] [Mathematical Formula 4]

[0066]

[0067] The position determination unit 212 is based on the bucket angle θ obtained by the acquisition unit 211. bk The measured values ​​and geometric data of the stick 152 are used to generate the bucket-stick transformation matrix T for transformation from the bucket coordinate system to the stick coordinate system using the following equation (5). bk am Bucket-stick transformation matrix T bk am It is to make Y-shaped bk Axis rotation bucket angle θ bk Furthermore, the deviation (x) between the origin of the parallel movement boom coordinate system and the origin of the bucket coordinate system bk y bk z bk The matrix is ​​used to determine the position. Additionally, the position determination unit 212 calculates the stick-world transformation matrix T. am w Bucket-stick transformation matrix T bk am The product of these components generates the bucket-world transformation matrix T, used for transforming from the bucket coordinate system to the world coordinate system. bk w .

[0068] [Mathematical Formula 5]

[0069]

[0070] Position determination unit 212 uses vehicle-world transformation matrix T tb w The relative position (x) of the center of gravity of the driving body 110, as shown by the geometric data of the driving body 110. tb＿com y tb＿com z tb＿com Convert to absolute position T tb＿com w The position determination unit 212 uses the rotation-world transformation matrix T. sb w The relative position (x) of the center of gravity of the rotating body 130 as shown by the geometric data of the rotating body 130. sb＿com y sb＿com z sb＿com Convert to absolute position T sb＿com w The position determination unit 212 uses the stick-world transformation matrix T bm w The relative position (x) of the center of gravity of boom 151 is shown by the geometric data of boom 151. bm＿com y bm＿com z bm＿com Convert to absolute position T bm＿com w The position determination unit 212 uses the stick-world transformation matrix T am w The relative position (x) of the center of gravity of the stick 152, as shown by the geometric data of the stick 152. am＿com y am＿com z am＿com Convert to absolute position T am＿com w The location determination unit 212 uses the bucket-world transformation matrix T. bk w The relative position (x) of the center of gravity of bucket 153 is shown by the geometric data of bucket 153. bk＿com y bk＿com z bk＿com Convert to absolute position T bk＿com w The location determination unit 212 uses the bucket-world transformation matrix T. bk w The relative position of the center of gravity of the load, as shown by the geometric data of bucket 153 (x) pl＿com y pl＿com z pl＿com Convert to absolute position T pl＿comw .

[0071] The center of gravity calculation unit 213 calculates the center of gravity position of the entire working machine 100 based on the center of gravity position of each part and the weight of each part determined by the position determination unit 212. Specifically, the center of gravity calculation unit 213 calculates the center of gravity position of the working machine 100 based on the known weight m of the traveling body 110. tb The weight of the rotating body at 130 degrees is m. sb The weight of boom 151m bm The weight of the boom 152m am And the weight of the bucket 153m bk The measured value of load cell 106 m pl The affine matrix T is obtained by the following equation (6). com w ', according to the affine matrix T com w 'Calculate the center of gravity T of the entire working machinery 100.' com w .

[0072] [Mathematical Formula 6]

[0073]

[0074] Through the calculation of equation (6), the centroid calculation unit 213 obtains a 4×4 affine matrix T as shown in equation (7). com w '.

[0075] [Mathematical Expression 7]

[0076]

[0077] The centroid calculation unit 213 extracts the obtained affine matrix T com w The translation component of ', that is, by using the affine matrix T com w The rotational component of ' is replaced with an identity matrix, as shown in equation (8), to calculate the position T of the center of gravity of the entire working machine 100. com w .

[0078] [Mathematical Formula 8]

[0079]

[0080] Based on the center of gravity position calculated by the center of gravity calculation unit 213, the energy calculation unit 214 calculates the energy required for the overturning of the working machine 100 for each rotation axis, i.e., the energy stabilization margin. The energy stabilization margin is a quantity expressed by equation (9). Figure 3 It is a diagram used to illustrate the energy stability margin.

[0081] [Mathematical Expression 9]

[0082]

[0083] That is, the energy stability margin is determined by the height z of the center of gravity of the working machine 100. com w The height z of the center of gravity when the center of gravity of the working machine 100 is directly above the axis of rotation. r＿com w The difference Q is obtained by multiplying the weight M of the working machine 100 and the gravitational acceleration g.

[0084] The energy calculation unit 214 uses each side of the support rectangle R containing the grounding point of the driving body 110 as the rotation axis ax1-ax4 to calculate the energy stability margin.

[0085] Consider setting the axis of rotation to X. ax Let the axis, which extends vertically, be designated as Z. ax Axis, will be with X ax Axis and Z ax Let the orthogonal axis be Y. ax In the case of a rotation axis coordinate system, the rotation axis-world transformation matrix T is used for transformation from the rotation axis coordinate system to the world coordinate system. ax1 w ~T ax4 w The length L, height h, and width w of the track of the traveling body 110 are expressed as in equation (10).

[0086] [Mathematical Formula 10]

[0087]

[0088] Energy calculation unit 214 is based on the rotation axis-world transformation matrix T obtained from equation (10). ax w Calculate the tilt angle θ of the Earth's surface about the rotation axis ax. gnd ax Additionally, the energy calculation unit 214 uses the rotation axis-world transformation matrix T ax w The inverse matrix and the overall center of gravity T of the working machine 100 com w The product is used to calculate the relative position T of the center of gravity of the working machine 100 in the rotating axis coordinate system. com ax The energy calculation unit 214, as shown in equation (11), is based on the relative position T of the center of gravity. com ax Z ax Axial translation component zcom ax With Y ax y-axis translation component com ax Calculate the elevation angle θ of the center of gravity as viewed from the axis of rotation. com ax .

[0089] [Mathematical Formula 11]

[0090]

[0091] It should be noted that atan2(x, y) in equation (11) is a function to find the deflection angle of the position (x, y) in the orthogonal coordinate system.

[0092] The energy calculation unit 214 is based on the tilt angle θ as shown in equation (12). gnd ax and the angle of elevation θ of the center of gravity com ax Calculate the rotation angle θ required for the center of gravity of the entire operating machine 100 to be directly above the axis of rotation. sup ax .

[0093] [Mathematical Formula 12]

[0094]

[0095] The energy calculation unit 214, as shown in equation (13), is based on the relative position T of the center of gravity. com ax Rotation angle θ sup ax and the rotation axis-world transformation matrix T ax w Calculate the rotation angle θ when the operating machinery is rotated by 100°. sup ax The absolute position T of the center of gravity of the entire working machine 100 r＿com w .

[0096] [Mathematical Formula 13]

[0097]

[0098] The energy calculation unit 214 calculates the absolute position T of the center of gravity after rotation. r＿com w Z w Axial translation component z r＿com w The absolute position T of the center of gravity before rotation com w Z w Axial translation component z comw The difference Q is used as the energy stabilization margin. It should be noted that the energy stabilization margin obtained here is equal to the energy stabilization margin obtained by normalizing the energy to units of length. It should be noted that, as shown in equation (7), if the absolute position T of the rotated center of gravity is... r＿com w The absolute position T of the center of gravity before rotation com w Z w Multiplying the difference Q of the axis translation components by the weight and gravitational acceleration of the working machine 100 yields the unnormalized energy stability margin. Therefore, the absolute position T of the center of gravity after rotation can be calculated. r＿com w The absolute position T of the center of gravity before rotation com w Z w The difference Q between the axis translation components is equivalent to calculating the energy stability margin.

[0099] The normalization unit 215 calculates the normalization margin (normalized value) by dividing the energy stability margin calculated by the energy calculation unit 214 by the length of the other side orthogonal to the side involved in the rotation axis. The normalization margin is a dimensionless quantity and represents the approximation of the most stable state of the working machine 100 relative to its rotation about the rotation axis. For example, the normalization unit 215 calculates the normalization margin by dividing the energy stability margin when rotating about the side end of the track (about the rotation axis ax2 or ax4) by the width w of the track. Alternatively, for example, the normalization unit 215 calculates the normalization margin by dividing the energy stability margin when rotating about the straight line connecting the front or rear ends of a pair of tracks (about the rotation axis ax1 or ax3) by the length L of the track.

[0100] Figure 4 This is a diagram showing the relationship between the energy stability margin and the position of the center of gravity. For example... Figure 4 As shown, the lower the position of the center of gravity, the higher the energy stability margin calculated in equation (7). In addition, the farther the distance between the rotation axis and the center of gravity, the higher the energy stability margin. That is, for a certain rotation axis, the energy stability margin taken by the working machine 100 is the largest when the center of gravity is located on the support rectangle R and is the point farthest from the rotation axis. Therefore, by dividing the energy stability margin calculated by the energy calculation unit 214 by the length of the other side orthogonal to the side involved in the rotation axis, the energy stability margin can be made dimensionless.

[0101] Evaluation unit 216 evaluates the tipping risk of the operating machinery 100 based on the normalized margin calculated by normalization unit 215. Specifically, evaluation unit 216 determines whether the normalized margin for each rotating axis exceeds a threshold. A threshold such as the attention threshold th can be considered. c Warning threshold th w Note the threshold th.c Greater than the warning threshold th w In addition, each threshold is greater than 0 and less than 1.

[0102] Based on the evaluation results of the evaluation unit 216, the output unit 217 generates an indication of the risk of the working machinery tipping over, which is displayed on the display device of the alarm device. Figure 5 This diagram illustrates an example of a tip-over risk indicator according to the first embodiment. The tip-over risk indicator displays an icon I1 for the vehicle 110, an icon I2 for the rotating body 130, and multiple indicator marks I3. The icon I2 for the rotating body 130 always faces upwards, indicating the front (front). The icon I1 for the vehicle 110 varies depending on the rotation angle θ. s The display is tilted. Multiple indicator markers I3 are displayed as icons I2 surrounding the rotating body 130. Figure 5 In the example shown, the tip-over risk indication uses 12 equally spaced indicator markers I3 arranged on a circle centered on icon I2. The indicator markers I3 indicate the height of the tip-over risk in the direction they represent by changing color. For example, indicator marker I3 turns yellow when the tip-over risk is at the caution level and red when the tip-over risk is at the warning level.

[0103] The output unit 217 outputs the evaluation results of the evaluation unit 216 to the alarm device. The output unit 217 outputs a label indicating the risk of the operating machinery tipping over to the alarm device. In addition, if the normalized margin with respect to at least one rotating axis is lower than the warning threshold for a certain period of time, the output unit 217 outputs an alarm tone to the alarm device to issue an alarm instruction.

[0104] Operation of Control Device 190

[0105] Figure 6 This is a flowchart illustrating the operation of the control device 190 according to the first embodiment.

[0106] When the control device 190 starts and executes the program, the following processing is performed at regular intervals.

[0107] The acquisition unit 211 acquires measurement values ​​from the tilt detector 101, slewing angle sensor 102, boom angle sensor 103, stick angle sensor 104, bucket angle sensor 105, and load cell 106 respectively (step S1). The position determination unit 212 determines the absolute position of the center of gravity of the traveling body 110, slewing body 130, boom 151, stick 152, bucket 153, and load using the various measurement values ​​acquired in step S1 and the geometric data recorded in the storage 250 (step S2).

[0108] The center of gravity calculation unit 213 calculates the absolute position T of the center of gravity of the entire machine 100 based on the absolute position of the center of gravity of the component determined in step S2 and the weight of the component recorded in the storage 250. com w (Step S3). Based on the center of gravity position calculated in step S3, the energy calculation unit 214 calculates the height Q of the energy required to tip over the working machine 100, i.e., the energy stabilization margin, for each side of the support rectangle R of the working machine 100 (Step S4).

[0109] Normalization unit 215 calculates a dimensionless normalization margin by dividing the height Q calculated in step S4 by the length of the other side orthogonal to the side involved in the rotation axis (step S5). Evaluation unit 216 compares the normalization margin of each side calculated in step S5 with the attention threshold th. c and warning threshold th w Compare (step S6).

[0110] Based on the measurement value of the rotation angle sensor 102 obtained in step S1, the output unit 217 determines the angle of the icon I1 of the vehicle 110 indicating the risk of tipping over (step S7). Furthermore, the output unit 217 determines the color of each indicator mark I3 based on the comparison result of step S6 (step S8). Specifically, the color of the indicator mark I3 opposite the side that forms the rotation axis and the adjacent indicator marks I3 on ​​both sides are determined to be the color corresponding to the comparison result of the normalized margin of the rotation axis.

[0111] Output unit 217 outputs a display indication of the generated tipping risk to the alarm device (step S9). Additionally, based on the comparison result of step S6, output unit 217 determines whether the normalized margin for at least one rotation axis is lower than the warning threshold th. w After a certain period of time (step S10), the output unit 217 detects that the normalized margin with respect to at least one rotation axis is below the warning threshold th. w If a certain period of time has passed (step S10: Yes), an alarm instruction is issued by outputting an alarm sound to the alarm device (step S11).

[0112] Function / Effect

[0113] Thus, the control device 190 of the first embodiment evaluates the likelihood of the work machine 100 tipping over for each side of the support rectangle R represented by the convex hull involving the grounding point of the work machine 100, based on the energy stability margin of the work machine 100 when that side is used as the axis of rotation and the length of the side of the support rectangle R. Therefore, the control device 190 is able to evaluate the likelihood of tipping over for each tipping direction where there is a possibility of tipping over with rotational movement.

[0114] It should be noted that, in other embodiments, the control device 190 can evaluate the possibility of tipping over in the same way as in the first embodiment when the convex hull involved in the grounding point of the working machine 100 is not rectangular, by using the longest distance among the multiple vertices of the convex hull from the rotation axis.

[0115] Furthermore, the control device 190 of the first embodiment calculates the normalized margin by dividing the energy stabilization margin by the length of the side supporting the rectangle R. Therefore, the control device 190 can evaluate the likelihood of tipping over on each side using the same threshold (attention threshold, warning threshold). Since the normalized margin is dimensionless, the control device 190 can use the same threshold for evaluation regardless of individual differences in the operating machinery 100. It should be noted that the control device 190 of other embodiments can also evaluate the unnormalized energy stabilization margin by using a threshold obtained by multiplying by the length of the side supporting the rectangle R.

[0116] <Second Implementation>

[0117] Figure 7 This is a schematic block diagram showing the structure of the control device 190 according to the second embodiment.

[0118] The control device 190 of the second embodiment includes a limiting unit 218 instead of the output unit 217 of the first embodiment. Furthermore, the evaluation unit 216 of the second embodiment may not generate a tipping risk indicator.

[0119] Based on the evaluation results of the evaluation unit 216, the limiting unit 218 restricts the operation of the traveling body 110, the rotating body 130, and the working device 150. For example, the limiting unit 218 restricts the operation of the traveling body 110, the rotating body 130, and the working device 150 when the normalized margin is lower than the warning threshold th. w If the time exceeds a certain threshold, the traveling body 110, the rotating body 130, and the working device 150 will be brought to a stop. As a result, the control device 190 can reduce the possibility of the machine tipping over due to the movement of the working machine 100.

[0120] It should be noted that in other embodiments, the limiting part 218 can also limit movement by reducing the operating speed instead of stopping the traveling body 110, the rotating body 130, and the working device 150. Furthermore, in other embodiments, the limiting part 218 can also limit the movement of any one or two of the traveling body 110, the rotating body 130, and the working device 150. In this case, if the posture is changed in a way that reduces the possibility of the working machine 100 tipping over by utilizing the operation of the unrestricted movable parts, the normalized margin becomes the warning threshold th. w In the above case, the restriction on the action of the restriction unit 218 is lifted.

[0121] <Other Implementation Methods>

[0122] The above description of one embodiment, with reference to the accompanying drawings, is detailed, but the specific configuration is not limited to the above method, and various design changes can be made. That is, in other embodiments, the order of the above processes can be appropriately changed. In addition, some processes can be performed in parallel.

[0123] The control device 190 described in the above embodiments can be a single computer, or the structure of the control device 190 can be separately configured in multiple computers, and the multiple computers can cooperate with each other to function as the control device 190. In this case, it is also possible that the computer constituting part of the control device 190 is installed inside the machine 100, while other computers are located outside the machine 100.

[0124] The work machine 100 described in the above embodiment includes a speaker and a display device as an alarm device. However, in other embodiments, it is not limited to this and may only have either a speaker or a display device. Furthermore, the alarm device is not limited to a speaker and a display device. For example, in other embodiments, the alarm device may be an actuator installed on the operating device. The actuator can warn the operator by applying a reaction force to the operation of the operating device performed by the operator. Alternatively, the actuator can warn the operator by causing the operating device to vibrate.

[0125] The work machine 100 described in the above embodiment is a hydraulic excavator, but it is not limited to this. For example, the work machine 100 in other embodiments may also be a wheel loader or other work machine equipped with tires but not tracks. Furthermore, the work machine 100 in other embodiments may not have a driving function. Additionally, in other embodiments, the supporting polygon may not be rectangular. Furthermore, the work machine 100 in other embodiments may replace the bucket 153 with other accessories such as a grab bucket, a breaker, or a crusher.

[0126] Industrial availability

[0127] Based on the above method, the likelihood of the work machinery tipping over can be evaluated by considering the relationship between the rotational motion and the tipping direction.

[0128] Explanation of reference numerals in the attached figures

[0129] 100…Working machinery; 101…Inclination detector; 102…Slewing angle sensor; 103…Boom angle sensor; 104…Stick angle sensor; 105…Bucket angle sensor; 106…Load gauge; 110…Traveling body; 130…Rotating body; 150…Working device; 151…Boom; 152…Stick; 153…Bucket; 170…Cab; 190…Control device; 210…Processor; 211…Acquisition unit; 212…Position determination unit; 213…Center of gravity calculation unit; 214…Energy calculation unit; 215…Normalization unit; 216…Evaluation unit; 217…Output unit; 218…Limiting unit; 230…Main memory; 250…Memory; 270…Interface.

Claims

1. A rollover evaluation system of a work machine having a work device, wherein the rollover evaluation system is provided with a processor, the processor is provided with: an energy calculation section that calculates, for each of a plurality of sides of a support polygon of the work machine, an energy required for the work machine to roll over with the side as a rotation axis; and an evaluation section that evaluates a possibility of the work machine rolling over, based on the energy calculated for each of the sides, the evaluation section evaluates the possibility of the work machine rolling over, based on a longest distance among distances from the side of the support polygon represented by a convex hull involving a grounding point to a plurality of vertices of the convex hull.

2. The rollover evaluation system according to claim 1, wherein the processor is further provided with a center-of-gravity position calculation section that calculates a center-of-gravity position of the work machine, the energy calculation section calculates the energy required for the work machine to roll over, based on the center-of-gravity position of the work machine.

3. The rollover evaluation system according to claim 1, wherein the support polygon is a rectangle, the evaluation section evaluates the possibility of the work machine rolling over, based on the energy of each of the sides and a length of a side orthogonal to the side.

4. The rollover evaluation system according to claim 1, wherein the evaluation section evaluates the possibility of the work machine rolling over by comparing a normalized value obtained by dividing the energy of each of the sides of the support polygon represented by a convex hull involving a grounding point by a longest distance among distances from the side to a plurality of vertices of the convex hull, with a threshold value.

5. The rollover evaluation system according to claim 1, wherein the rollover evaluation system is provided with a display device, the processor is further provided with an output section, the output section generates an indicator indicating a rollover risk of the work machine based on a result of the evaluation of the possibility of the rollover by the evaluation section, and outputs to the display device.

6. The rollover evaluation system according to claim 5, wherein an icon representing an appearance of the work machine and a plurality of indicator marks arranged in a manner surrounding a periphery of the icon are included in the indicator, the output section makes a form of an indicator mark of the plurality of indicator marks arranged at a position corresponding to a side of the work machine determined by the evaluation section as having a high possibility of the work machine rolling over different from forms of the other indicator marks.

7. The rollover evaluation system according to claim 1, wherein the processor is provided with a restriction section that restricts a movement of the work machine in a case where the result of the evaluation of the possibility of the rollover indicates a high possibility of the work machine rolling over.

8. A rollover evaluation method, wherein the rollover evaluation method includes: a step of calculating, for each of a plurality of sides of a support polygon of a work machine having a work device, an energy required for the work machine to roll over with the side as a rotation axis; and a step of evaluating a possibility of the work machine rolling over, based on the energy calculated for each of the sides, the evaluation section evaluates the possibility of the work machine rolling over, based on a longest distance among distances from the side of the support polygon represented by a convex hull involving a grounding point to a plurality of vertices of the convex hull. The step of evaluating the possibility of the rollover of the work machine includes a step of evaluating the possibility of the rollover of the work machine based on a longest distance among distances from the edges of the support polygon represented by a convex hull involving the grounding point to a plurality of vertices of the convex hull.

9. A work machine, wherein The work machine is provided with: a traveling body; a turning body supported to the traveling body in a turnable manner; a work device mounted to the turning body; and a processor, The processor is provided with: a center-of-gravity position calculation section that calculates a center-of-gravity position of the work machine; an energy calculation section that calculates, for a plurality of edges of a support polygon of the traveling body, an energy required for a rollover of the work machine with the edge as a rotation axis based on the center-of-gravity position of the work machine; and an evaluation section that evaluates a possibility of the rollover of the work machine based on the energy calculated for each of the edges, The evaluation section evaluates the possibility of the rollover of the work machine based on a longest distance among distances from the edges of the support polygon represented by a convex hull involving the grounding point to a plurality of vertices of the convex hull. ​

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