Work machinery

Abstract

To provide a work machine that can ensure good operability by not performing unnecessary speed restriction when there is no possibility of deviation from a target surface and by appropriately performing deceleration and stopping control even when the situation changes to one in which deviation from the target surface is expected.SOLUTION: A control machine calculates an estimated movement trajectory of a bucket tip and calculates a positional relation between a target surface and the estimated movement trajectory, based on an attitude of a work device and a required operating direction. When it is determined that the estimated movement trajectory intersects with the target surface based on the calculated positional relation, a bucket tip speed is restricted while maintaining the required operating direction. When it is determined that the estimated movement trajectory does not intersect with the target surface based on the calculated positional relation, the bucket tip speed is controlled using a tip speed based on an operation signal output from an operating device.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a work machine. [Background technology]

[0002] Known work machines used in road construction, building construction, civil engineering, dredging, and the like include a work machine body having a rotating body rotatably attached to the upper part of a traveling body that travels by a power system, a multi-jointed work front attached to the work machine body so as to be able to swing freely in the vertical direction, and each front member constituting the work front is driven by a cylinder. One example is a so-called hydraulic excavator having a work front composed of a boom, an arm, a bucket, and the like. Some hydraulic excavators of this type perform so-called machine control, in which the target surface to be excavated is set in advance and the boom operation, etc. are automatically controlled in accordance with the amount of arm operation by the operator so that the bucket can excavate along the target surface.

[0003] Machine control is a semi-automatic control function in which a controller controls front operations while an operator operates them manually, so in addition to control accuracy, ease of operation by the operator is also important. Prior art related to machine control is known, for example, from Patent Document 1 and Patent Document 2.

[0004] Patent Document 1 discloses a construction machinery control system that, when calculating the speed limit of the work equipment from the target surface distance and the target speed of the work implement, limits the speed of the boom rather than the arm, thereby relaxing the speed limit of the arm, which is strongly influenced by the operator's operating intention during excavation, and minimizing any discomfort felt by the operator.

[0005] Patent Document 2 discloses a work machine that determines whether or not there is a possibility that the work implement will intrude into the target surface when operating the arm, based on a set target surface and signals from a position sensor and an attitude sensor, and if it is determined that there is no possibility that the work implement will intrude into the target surface, controls the speed so that it does not slow down even if the position of the work implement is close to the target surface, understands the operator's intention to move the work implement quickly near the excavation surface, avoids restricting the arm, and minimizes any discomfort felt by the operator. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2014 / 167718 [Patent Document 2] International Publication No. 2021 / 064385 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the conventional technology described in Patent Document 1, the speed limit is calculated based on the distance of the work tool from the target surface. Therefore, even if the trajectory of the moving claw tip cannot deviate from the target surface near the target surface, the operating speed is limited, which may result in a situation contrary to the operator's intention to move quickly, resulting in a deterioration in operability.

[0008] The conventional technology described in Patent Document 2 determines whether or not an intrusion is possible based on the posture state and the input state of the operating lever, and determines whether or not to restrict the work equipment.Therefore, if an input that may indicate an intrusion is suddenly made when it is determined that no intrusion will occur and the speed is not restricted, a sudden deceleration operation is required, which may result in the operation not being stopped completely and deviating from the target plane, or a shock due to the sudden deceleration may occur, which may impair the operator's operability and workability.

[0009] The present invention has been made in view of the above, and an object of the present invention is to provide a work machine that does not impose unnecessary speed restrictions when there is no possibility of deviation from the target plane, and that can ensure good operability by performing appropriate deceleration and stop control even if the state changes to one in which deviation from the target plane is expected. [Means for solving the problem]

[0010] The present application includes a plurality of means for solving the above problems, and one example thereof is a crawler body, an upper rotating body provided so as to be able to rotate relative to the crawler body, a working device having a bucket attached to the upper rotating body and swingable at least in the vertical direction, an actuator for driving the upper rotating body and the working device, an operating device for operating the actuator, an operation amount detection device for detecting an operation amount of the operating device, an attitude detection device for detecting an attitude of the upper rotating body and the working device, a target surface setting device for setting a target surface to be excavated by the bucket, and a control device for calculating a required operation direction for the bucket based on the operation amount detected by the operation amount detection device, and controlling the bucket so that the bucket does not exceed the target surface based on the required operation direction. In a work machine having a control device that calculates an operation command value for the actuator so that the required operation direction is not exceeded, and a drive device that drives the actuator based on the operation command value of the control device, the control device calculates an estimated movement trajectory of the tip of the bucket based on the attitude of the work device and the required operation direction, and calculates the positional relationship between the target surface and the estimated movement trajectory, and if it is determined that the estimated movement trajectory intersects with the target surface based on the calculated positional relationship, it limits the tip of the bucket speed while maintaining the required operation direction, and if it is determined that the estimated movement trajectory does not intersect with the target surface based on the calculated positional relationship, it controls the tip of the bucket speed using a tip speed based on an operation signal output by the operating device. [Effects of the Invention]

[0011] According to the present invention, when there is no possibility of deviation from the target plane, unnecessary speed restrictions are not imposed, and even if the state changes to one in which deviation to the target plane is expected, appropriate deceleration and stopping control can be performed, thereby ensuring good operability. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a side view schematically showing the overall configuration of a hydraulic excavator, which is an example of a work machine. [Figure 2] FIG. 2 is a diagram illustrating the main controller together with related components. [Figure 3] FIG. 2 is a functional block diagram showing the processing contents of a main controller. [Figure 4] FIG. 10 is a diagram showing the relationship between a target surface and an estimated toe movement trajectory. [Figure 5] FIG. 10 is a diagram showing the relationship between a target surface and an estimated toe movement trajectory. [Figure 6] 10 is a flowchart showing the processing contents of the main controller. [Figure 7] 10 is a flowchart showing the processing contents of the main controller. [Figure 8] FIG. 10 is a diagram showing the relationship between a target surface and an estimated toe movement trajectory. [Figure 9] FIG. 10 is a diagram showing the relationship between a target surface and an estimated toe movement trajectory. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0014] <Target device> The subject of this embodiment is made up of a work machine 1 and a construction target surface. The construction target surface is a construction target surface that has so-called three-dimensional information, that is, information on the left and right directions in addition to the front and rear directions of the work machine 1. The construction target surface may be set relative to the work machine 1, or may be set in a global coordinate system based on the construction site or the Earth.

[0015] <Device configuration> FIG. 1 is a side view showing a schematic overall configuration of a hydraulic excavator, which is an example of a work machine according to this embodiment.

[0016] As shown in Fig. 1, the work machine 1 includes a front work unit 2 (working device), a revolving unit 3 (upper revolving unit), and a running unit 4. The revolving unit 3 (upper revolving unit) and the running unit 4 form the work machine main body.

[0017] The front work unit 2 is configured to rotate relative to the rotating unit 3, and the rotating unit 3 is configured to rotate relative to the running unit 4, each centering on a connecting portion. The front work unit 2 is equipped with a boom 20 having one end connected to the rotating unit 3, an arm 21 having one end connected to the boom 20, a bucket 22 having one end connected to the arm 21, a boom cylinder 20A having both ends connected to the boom 20 and the rotating unit 3, respectively, an arm cylinder 21A connected to the arm 21 and the boom 20, respectively, a link A 22B, a link B 22C, and a bucket cylinder 22A connected to link B 22C and the arm 21. These members are configured to rotate vertically, each centering on a connecting portion. The running unit 4 is equipped with a travel motor 41 and a crawler track 45.

[0018] The boom cylinder 20A, arm cylinder 21A, and bucket cylinder 22A are each hydraulically extendable and retractable, and the extension and contraction of these cylinders allows the boom 20, arm 21, and bucket 22 to rotate. The bucket 22 can be replaced with any attachment (not shown), such as a grapple, breaker, ripper, magnet, or rotary tilt bucket.

[0019] The boom 20 and the arm 21 are respectively equipped with an IMU (Inertial Measurement Unit) (boom) 20S and an IMU (arm) 21S for detecting the attitudes of the boom 20 and the arm 21. The link A 22B is equipped with an IMU (bucket) 22S for detecting the attitude of the bucket 22. The IMU (boom) 20S, IMU (arm) 21S, and IMU (bucket) 22S are each composed of an angular velocity sensor and an acceleration sensor.

[0020] The boom cylinder 20A is equipped with a pressure sensor (boom rod) 20RP and a pressure sensor (boom bottom) 20BP for detecting the load. The arm cylinder 21A is equipped with a pressure sensor (arm rod) 21RP and a pressure sensor (arm bottom) 21BP for detecting the load. The bucket cylinder 22A is equipped with a pressure sensor (bucket rod) 22RP and a pressure sensor (bucket bottom) 22BP for detecting the load.

[0021] The rotating body 3 includes a rotation angle sensor 2S, an IMU (rotating body) 30S, a main frame 31, a cab 32, a main controller 34, a drive unit 35, a prime mover 36, a rotation load measuring device 37, and a position measuring device 250.

[0022] The turning angle sensor 2S is attached so as to be able to detect the relative angle between the running body 4 and the turning body 3.

[0023] The IMU (rotating body) 30S includes an acceleration sensor and an angular velocity sensor, and is attached so as to be able to detect the tilt angle of the rotating body 3.

[0024] The operator's cab 32 is equipped with an operation device 33 , a setting input / display device 100 , and a construction surface management device 2000 .

[0025] The operation device 33 is composed of an operation lever and is provided with an operation amount detection device that detects the amount by which the operation lever is tilted. The operation amount detection device is composed of an operation amount detection sensor such as an angle sensor provided on the operation lever, and is attached so that by detecting the amount by which the operator tilts the operation lever, it can convert the target operation of each movable part requested by the operator into an electric signal.

[0026] The construction surface management device 2000 is connected to the setting input / display device 100 and is installed so as to be able to manage and store the construction target surface that is the target for excavation by the front work unit 2.

[0027] The setting input / display device 100 is composed of a display monitor and a touch panel, and is attached so that it can display the posture of the work machine 1, information on the construction target surface, the positional relationship and distance between the construction target surface and the work front 2, etc., and can also set various dimensions and mass of the work front 2.

[0028] FIG. 2 is a diagram showing the main controller together with the related components.

[0029] As shown in FIG. 2, the drive device 35 is composed of an electromagnetic control valve and a directional change valve, and is installed so as to operate the drive actuators, that is, the boom cylinder 20A, the arm cylinder 21A, and the bucket cylinder 22A, by driving the electromagnetic control valve and the directional change valve in accordance with operation command values ​​instructed by the main controller 34.

[0030] The prime mover 36, which is the power source, is made up of an engine 36a and a hydraulic pump 36b connected to the output shaft of the engine 36a. More specifically, the hydraulic pump 36b is driven by the power of the engine 36a, and is installed so that the power required to operate the work machine 1 is generated by the pressurized oil discharged by the hydraulic pump 36b.

[0031] The swing load measuring device 37 is made up of a pressure sensor and is attached so as to be able to measure the load in the swing direction of the swing body 3.

[0032] The running body 4 is equipped with tracks, and the operator can make the work machine 1 travel by operating the operating device 33. The running body 4 is not limited to one equipped with tracks, but may be one equipped with running wheels made up of tires. Note that in this embodiment, a mobile work machine equipped with the running body 4 has been described as an example, but the present invention is not limited to this, and may be one that is fixed to a construction site, for example.

[0033] The configuration of the work machine 1 is an example, and the work machine 1 may have a similar device or configuration.

[0034] FIG. 3 is a functional block diagram showing the processing contents of the main controller.

[0035] As shown in FIG. 3, the main controller 34 provided in the work machine 1 is connected to an operation device 33, an attitude detection device 200, a load measurement device 210, a position measurement device 250, a drive device 35, a construction surface management device 2000, and a setting input / display device 100.

[0036] The construction surface management device 2000 is connected to the setting input / display device 100 .

[0037] The driving device 35 is connected to a prime mover 36 and an actuator 2ACT.

[0038] <Detailed configuration and functions of the device> <Operating device 33> The operating device 33 is composed of an operating lever and is provided with an operation amount detection device that detects the amount by which the operating lever is tilted. The amount by which the operating lever is operated by the operator (i.e., the amount of tilt) is detected by the operation amount detection device and converted into an electrical signal. In hydraulic excavators, the operating speed of the actuators is generally set to increase as the amount by which the lever is tilted increases, and the operator operates the work machine by changing the amount by which the lever is tilted, thereby changing the operating speed of each actuator. Note that the operating device 33 may be of a hydraulic pilot type or a remotely controlled type, as long as it has equivalent functions.

[0039] <Posture detection device 200> The attitude detection device 200 is equipped with an angular velocity sensor and an acceleration sensor in each of the IMU (swivel unit) 30S, IMU (boom) 20S, IMU (arm) 21S, and IMU (bucket) 22S, and further equipped with a swing angle sensor 2S. Attitude information of the work machine 1 can be obtained from these IMUs and angle sensors. The boom 20, arm 21, bucket 22, boom cylinder 20A, arm cylinder 21A, bucket cylinder 22A, link A 22B, link B 22C, and revolving unit 3 are each mounted so as to be able to swing, so the attitudes of the boom 20, arm 21, bucket 22, and revolving unit 3 can be estimated from the mechanical link relationships. Note that the attitude detection method shown here is just one example, and the relative angles of each part of the work front 2 may be directly measured, or the strokes of the boom cylinder 20A, arm cylinder 21A, and bucket cylinder 22A may be detected to calculate the attitude of each part of the work machine 1.

[0040] <Position measurement device 250> The position measurement device 250 may be a GNSS (Global Navigation Satellite System), a laser positioner, or a total station. Position measurement devices other than those mentioned above may also be provided as long as they can identify the position of the work machine 1.

[0041] <Driver 35> The drive unit 35 is made up of an electromagnetic control valve and a directional change valve, and controls the amount of pressurized oil supplied to the cylinders and hydraulic motors that drive each part of the work machine according to operation command values ​​issued from the main controller 34. The operation command value output from the main controller 34 is converted into pilot pressure by the electromagnetic control valve, and the pilot pressure drives the directional change valve, which controls the amount of movement of the actuator. The hydraulic oil, the flow rate of which is adjusted by the directional change valve, is supplied to the cylinders and hydraulic motors that drive each part of the work machine, and drives each moving part. In addition, by adding or changing the configuration, it is possible to drive additional attachments and equipment not included above.

[0042] <Motor Device 36> The power unit 36 ​​is made up of an engine and a hydraulic pump, and generates as power the hydraulic pressure required to operate the work machine 1. In addition to the above, it may also be possible to extract hydraulic power from an electrically driven motor.

[0043] <Actuator 2ACT> Actuator 2ACT is a general term for actuators including boom cylinder 20A, arm cylinder 21A, bucket cylinder 22A, a hydraulic motor for swinging, a hydraulic motor for traveling, and the like.

[0044] <Construction surface management device 2000> The construction surface management device 2000 can set and manage a construction target surface for the work machine 1 using the setting input / display device 100. The construction target surface can be set to have multiple planes in addition to a single plane, and the range that can be excavated by the work front 2 can be set. The construction target surface can be set relative to the work machine 1 as the base, or it can be set in a coordinate system based on the construction site or the earth.

[0045] <Settings input / display device 100> The setting input / display device 100 can display to the operator the posture of the work machine 1, area information of the construction target surface set by the construction surface management device 2000, the distance between the work front 2 and the construction target surface, and the like.

[0046] <Main Controller 34> As shown in FIG. 3, the main controller 34 is connected to the operation device 33, the construction surface management device 2000, the setting input / display device 100, the attitude detection device 200, the position measurement device 250, and the drive device 35, and is composed of an attitude calculation unit 310, a target surface distance calculation unit 320, a required speed calculation unit 330, an estimated toe movement trajectory calculation unit 340, a target surface interference determination unit 350, a required speed holding unit 360, a memory unit 370, a speed limit coefficient calculation unit 400, a target speed calculation unit 410, and an operation command value calculation unit 430.

[0047] The attitude calculation unit 310 calculates the attitude of the work machine 1 based on the information from the attitude detection device 200.

[0048] The target surface distance calculation unit 320 uses the attitude and position information of the work machine 1 to calculate the distance to the construction target surface (hereinafter referred to as the target surface distance).

[0049] The required speed calculation section 330 calculates the operating speed required of the work machine 1 using the attitude of the work machine 1 and the amount of operation by the operator.

[0050] The estimated toe movement trajectory calculation unit 340 uses the attitude and required speed of the work machine 1 to estimate the movement of the toe of the bucket, thereby calculating an estimated toe movement trajectory (hereinafter, movement trajectory).

[0051] The target surface interference determination unit 350 determines whether or not the toe of the bucket is estimated to interfere with the construction target surface, using the construction target surface information and the movement trajectory.

[0052] The required speed holding unit 360 holds the required speed using the required speed, the target surface interference determination result, and the speed limit coefficient, and applies the held required speed to the speed limit coefficient calculation unit.

[0053] The storage unit 370 is made up of a memory that stores various settings and information input by the setting input / display device 100, and transmits them to each functional unit of the main controller .

[0054] The speed limit coefficient calculation unit 400 calculates a speed limit coefficient for correcting the required speed in accordance with the posture information of the work machine 1, the target surface distance, the required speed to be maintained, and the target surface interference determination result.

[0055] The target speed calculation unit 410 calculates the target speed of the actuator 2ACT in accordance with the attitude information of the work machine 1, the target surface distance, the required speed and the speed limit coefficient.

[0056] The operation command value calculation unit 430 generates an operation command value for controlling the driving device 35 based on the target speed of the actuator 2ACT calculated by the target speed calculation unit 410.

[0057] <Device Operation and Calculation Method> <Machine control operation> In machine control, a controller controls the operation of a work machine 1 so that the implement of the work machine, which is driven based on the operator's operation, operates without sinking into the target construction surface. For example, when operating the front toward the target surface to perform excavation with a bucket, the front speed is reduced from the approach stage to bring the toe closer to the target surface so that the bucket toe position does not deviate from the target surface, and if the toe is above the target surface, the front operation is restricted so that it does not move any further below the target surface. This control is performed by calculating the operator's requested speed, which quantitatively gives the operation required by the operator, and calculating the target speed based on the calculation result of the speed limit coefficient.

[0058] <Method of Calculating Required Speed: Required Speed ​​Calculation Unit 330> One method for calculating the operator's required movement is to calculate a required speed vector based on the amount of lever operation. Since the work machine 1 is all mechanically connected and there is a one-to-one correspondence between the levers operated by the operator and the actuator operations, the amount of lever operation can be obtained as the speed of each actuator, i.e., the required speed. Therefore, for example, it is possible to express as a vector the direction and amount of movement of the tip of the bucket 22 (hereinafter simply referred to as the tip) in response to the amount of lever operation.

[0059] Figures 4 and 5 are diagrams showing the relationship between the target surface and the estimated tip movement locus.

[0060] In the case shown in Figure 4, the vector points to a dotted arrow extending diagonally downward to the right from the tip. Further, if the required speed defined as above is defined as V, the required speed V is decomposed into a speed component V_x parallel to the construction target surface, which is defined by a dotted arrow extending to the right from the tip, and a speed component V_z perpendicular to the construction target surface, which is defined by a dotted arrow extending downward from the tip. Hereinafter, the component parallel to the construction target surface is defined as the x-component, and the component perpendicular to the construction target surface is defined as the z-component.

[0061] In the above description, as one method of calculating the required operation of the operator, a method of calculating the required operation vector based on the lever operation amount is shown. However, as long as the required operation of the operator can be calculated or determined, methods other than the above may be used. Also, based on the mass of the work machine, V_x and V_z may be corrected by a certain correction value α. As an example of the correction value α, for example, when a sudden lever operation is input, a maximum value is set for the time change amount of the required speed so that acceleration and deceleration can be performed reasonably except in an emergency, and a value that does not exceed this is used. Thus, an operation that conforms to the operator's intuition that a larger mass is difficult to accelerate and decelerate (this is also an operation that conforms to physical properties) can be performed.

[0062] <Calculation method of target surface distance: Target surface distance calculation unit 320> As shown in Figure 4, the target surface distance is defined and calculated by the shortest distance d between the tip and the construction target surface. Note that as long as a variable can be defined and calculated such that the value becomes smaller as the distance between the work machine 1 and the construction target surface becomes closer, methods other than the above may be used.

[0063] <Calculation method of speed limit coefficient for z-component: Speed limit coefficient calculation unit 400> The speed limit coefficient for the z-component is calculated using the required speed component V_z perpendicular to the target surface and the target surface distance d, and is a dimensionless quantity defined by b_z. Here, the closer b_z is to 0, the stronger the speed limit; the closer b_z is to 1, the weaker the speed limit; and b_z = 1 means no speed limit is applied. Furthermore, as shown in the following (Equation 1), (Equation 2), and (Equation 3), when d = 0, b_z = 0, and at a certain target surface distance d1, b_z = 1. When d is greater than 0 but less than d1, b_z also takes on larger values ​​in the range greater than 0 but less than 1 as d increases (i.e., the rate of change b_z' of b_z with respect to d takes a positive value), and when d is d1 or greater, b_z takes on a constant value of 1. Note that, generally, d1 takes on larger values ​​as V_z increases, but any value may be used for d as long as the implement of the work machine 1 operates without diving into the target surface. When b_z calculated by the above method is finally transmitted to the target speed calculation, i.e., adopt and apply a speed limiting factor Control " Restrictions apply This is called "control."

[0064] d=0;b_z=0 …(Formula 1) 0 <d<d1;0<b_z<1 かつ b_z‘> 0…(Formula 2) d>=d1;b_z=1 …Equation (3) In addition Restrictions apply The b_z calculated by the control may be rejected depending on the positional relationship between the target surface and the movement trajectory, which will be described later, and may be defined as a different value between 0 and 1.

[0065] < Restrictions apply Method of calculating the speed limit coefficient of the x component in control: Speed ​​limit coefficient calculation unit 400 The speed limiting coefficient b_x of the x component is calculated as shown in the following (Equation 4) using the speed limiting coefficient b_z of the z component calculated by the above method.

[0066] b_x=b_z …(Formula 4) In addition, Restrictions applyThe b_z calculated by the control may be rejected depending on the positional relationship between the target surface and the movement trajectory, which will be described later, and may be defined as a different value between 0 and 1.

[0067] <Method of Calculating Movement Trajectory: Estimated Toe Movement Trajectory Calculation Unit 340> The movement trajectory is defined by the x-component V_x and z-component V_z of the current attitude and required speed of the work machine 1. First, as shown in FIG. 4 and equation (5), the vector direction θ of the required speed is defined by V_x and V_z.

[0068] θ=Tan^(-1)(V_x / V_z) …(Equation 5) Next, assuming that the required speed is the speed given by the boom and arm of the work machine 1, the operation amount ratio of the boom and arm to achieve θ is uniquely determined. If it is assumed that the work machine 1 continues to operate while maintaining a constant operation amount ratio, it will trace a trajectory that is convex downward and passes through the current tip of the bucket, as shown in Figure 4. This type of trajectory is defined as the "estimated movement trajectory."

[0069] The movement trajectory may be defined over the entire range of motion of the boom and arm of the work machine 1, or may be defined within a range of a separately defined effective length β. Furthermore, if a method other than the above can estimate the movement trajectory with greater accuracy, the movement trajectory may be defined using that method. For example, the effective length β may be defined as the shorter of the length predicted up to a predetermined time later and the length predicted up to the end of the range of motion. Furthermore, the effective length β may be determined taking into account the surrounding environment at the time of prediction and the computational cost.

[0070] <Method of calculating the positional relationship between the construction target surface and the movement trajectory: Target surface interference determination unit 350> The movement trajectory may have no intersection with the construction target surface as shown in Figure 4, or may have an intersection with the construction target surface as shown in Figure 5. If a two-dimensional plane model is assumed and the construction target surface is defined as a straight line at z = 0, the positional relationship between the movement trajectory and the construction target surface can be determined as follows: if the positive and negative z coordinates of the entire movement trajectory are always constant, there is no intersection with the construction target surface; if the positive and negative z coordinates switch, there is an intersection with the construction target surface.

[0071] If it is possible to make a determination, other numerical models may be defined and used for calculation.

[0072] <Definition and calculation method of limit release control> When it is determined by the calculation of the positional relationship that the construction target surface and the movement trajectory have no intersection with each other, as shown in FIG. 4, Restrictions apply The value of the z-component speed limit coefficient b_z calculated by the control is discarded and instead applied as b_z = 1. At the same time, the value of the x-component speed limit coefficient b_x is also applied as b_x = 1.

[0073] Here, it is assumed that the situation where b_x=b_z=1 occurs due to (State 1) and (State 2) shown below.

[0074] State 1: When d>=d1, regardless of the relationship between the construction target surface and the movement trajectory State 2: The construction target surface and the movement trajectory have no intersection with each other, and d <d1であるとき In (State 1), Restrictions apply In (State 1), the bucket tip speed is defined as being in a "limit release control" state, and in (State 2), the bucket tip speed is defined as being in a "limit release control" state. If the bucket tip speed were controlled only by the magnitude of the target surface distance d, a target speed lower than the requested speed would be calculated. However, in "limit release control," the calculation result is rejected based on the positional relationship between the construction target surface and the movement trajectory, and the target speed is set to the same value as the requested speed.

[0075] Furthermore, (State 3) is defined as follows:

[0076] State 3: The construction target surface and the movement trajectory have an intersection with each other, and d <d1であるとき In the situation where the state switches from (State 1) to (State 3), Restrictions apply It would be fine to continue executing the control, but when switching from (State 2) to (State 3), the time changes of b_x and b_z become significantly larger as shown in Figure 8, raising the risk that control will not be able to be completed in time and the control target surface will interfere with the bucket. Therefore, calculations to reduce this risk are performed using the method described below.

[0077] <Definition of holding toe velocity vector: required velocity holding unit 360> In the limit release control state, assuming a situation where the state switches from (State 2) to (State 3), the current required speed is recorded in the required speed storage unit to support the calculation method described below. A speed vector constructed based on the recorded required speed is called the held toe speed vector V_hold.

[0078] <Calculation method when the control state switches from the limit release state to the state where the movement trajectory interferes with the target surface> In the limit release control state, when the state switches from (State 2) to (State 3), this is defined as a "limit release deviation." In the "limit release deviation" state, as shown in FIG. 9, a resultant vector direction Φ is calculated, which is defined by the vector V+V_hold, which is a combination of the current toe speed vector V and the held toe speed vector V_hold held in the required speed holding unit. Furthermore, the z-component speed limit coefficient b_z is determined, for example, using one of the above (Equation 1), (Equation 2), or (Equation 3), and the x-component speed limit coefficient b_x is calculated based on Φ and the x-component required speed V_x. Note that b_z may be determined using another method as long as there is no interference between the construction target surface and the bucket.

[0079] <Target speed calculation method> The x-component V_xlim of the target speed V_lim is calculated using the speed limit coefficient b_x of the x-component and the x-component V_x of the required speed V as shown in Equation 6 below, and the z-component V_zlim of the target speed V_lim is calculated using the speed limit coefficient b_z of the z-component and the z-component V_z of the required speed V as shown in Equation 7 below.

[0080] V_xlim=b_x×V_x …(Formula 6) V_zlim=b_z×V_z …(Equation 7) An example of calculation and operation is shown in Figure 9. For example, when the movement trajectory is in a positional relationship where it does not intersect with the construction target surface, the above (Equation 4) holds, and V_xlim is equal to V_x, and V_zlim is equal to V_z. Furthermore, if (State 2) applies, the target speeds V_xlim' and V_zlim', which would be calculated if the bucket tip speed were controlled only by the magnitude of the target surface distance d, are also potentially calculated, but are actually discarded.

[0081] Next, consider the case where the required speed V changes and the system switches to (State 3). In conventional technology, the target speed was given in the same vector direction as the required speed vector, so the movement trajectory would not change due to control. Therefore, if the system switches to (State 3) when the target surface distance d is small, there is a risk that control will not be able to be completed in time and the bucket will interfere with the work target surface. In contrast, in the present invention, the target speeds V_xlim and V_zlim are given in the same vector direction as the vector direction Φ defined by the vector V+V_hold, which is a combination of the current toe speed vector V and the held toe speed vector V_hold held in the required speed holding unit, thereby changing the movement trajectory and reducing the risk.

[0082] <Control procedure> 6 and 7 are flowcharts showing the processing contents of the main controller.

[0083] As shown in Figures 6 and 7, first, the main controller 34 acquires and calculates the attitude of the work machine (step S100), acquires and calculates information about the construction target surface (step S110), acquires and calculates the amount of operation by the operator (step S120), calculates the speed required by the operator (step S130), calculates an estimated toe movement trajectory (step S140), calculates the positional relationship between the construction target surface and the estimated toe movement trajectory (step S150), and provisionally calculates a speed limit coefficient b_z of the z component based on the target surface distance d (step S160).

[0084] Here, it is determined whether or not there is an intersection between the construction target surface and the estimated toe movement trajectory (step S170).

[0085] If the determination result in step S170 is YES, that is, if it is determined that an intersection exists, it is then determined whether the speed limiting coefficient b_z of the z component temporarily calculated in step S160 is 1 (step S180).

[0086] If the determination result in step S180 is NO, that is, if the speed limit coefficient b_z is other than 1, the control mode when the processing shown in FIGS. 6 and 7 was executed last time is then determined. Restrictions apply It is determined whether or not the control was performed (step S200). If the calculation has not been performed immediately before, such as at the start of the control, Restrictions apply The judgment is made assuming that it was control.

[0087] If the determination result in step S200 is YES, the speed limiting coefficient b_z of the z component temporarily calculated in step S160 is applied as a numerical value to be passed to the target calculation unit, and further, the speed limiting coefficient b_x of the x component is set to the same value as b_z (step S220). Machine Control Under control (Restrictions being applied) It is determined that this is the case (step S230).

[0088] If the result of the determination in step S200 is NO, that is, if the previous calculation Restrictions applyIf it is not control, the held toe velocity vector and the current toe velocity vector are combined to calculate the vector direction Φ (step S240), the speed limit coefficient b_z of the z component temporarily calculated in step S160 is applied as a numerical value to be passed to the target calculation unit, and further the speed limit coefficient b_x of the x component is calculated so that the vector direction becomes Φ (step S250), and it is determined that the restriction release deviation processing is in progress (step S260).

[0089] Furthermore, if the determination result in step S170 is NO (i.e., if it is determined that no intersection exists), or if the determination result in step S180 is YES (i.e., if the speed limiting coefficient b_z is 1), the speed limiting coefficients b_x and b_z of the x and z components are set to 1 (step S190), and then it is determined whether the speed limiting coefficient b_z of the provisionally calculated z component is 1 (step S210).

[0090] If the determination result in step S210 is YES, that is, if the speed limit coefficient b_z is 1, Machine Control Under control (Normal control) It is determined that this is the case (step S270).

[0091] Also, if the determination result in step S210 is NO, that is, if the speed limit coefficient b_z is other than 1, the held toe speed vector is updated to the current toe speed vector (step S280), and it is determined that limit release control is underway (step S290).

[0092] After the processing of any one of steps S230, S260, S270, and S290 is completed, the target speed is calculated based on the speed limit coefficient calculated in step S190, step S220, or step S250 (step S300).

[0093] Next, an operation command value for operating the work machine is calculated (step S310), and the operation command value is transmitted to the drive device (step S320), thereby terminating the process.

[0094] <Effects of this embodiment> As described above, according to this embodiment, when there is no possibility of deviation from the target surface even when the bucket is near the target surface, it is possible to move the bucket in the direction intended by the operator without imposing unnecessary speed restrictions, and even when the state switches to one in which deviation from the target surface is anticipated, it is possible to appropriately transition to a deceleration / stop control state, thereby ensuring good operability.

[0095] <Other> The present invention is not limited to the above-described embodiments and includes various modifications within the spirit and scope of the present invention. For example, the present invention is not limited to those including all of the configurations described in the above-described embodiments and includes those in which some of the configurations are omitted. It is also possible to add or replace part of the configuration of one embodiment with the configuration of another embodiment. The components of the above-described control device, as well as their functions and execution processes, may be implemented in part or in whole by hardware (e.g., by designing logic that executes each function using an integrated circuit). The components of the above-described control device may also be implemented as a program (software) that is read and executed by an arithmetic processing unit (e.g., a CPU) to realize the functions of the control device. Information related to the program may be stored in, for example, a semiconductor memory (e.g., a flash memory, an SSD), a magnetic storage device (e.g., a hard disk drive), or a recording medium (e.g., a magnetic disk, an optical disk), etc. [Explanation of symbols]

[0096] 1...work machine, 2...work front, 2ACT...actuator, 2S...swing angle sensor, 3...swinging body, 4...traveling body, 20...boom, 20A...boom cylinder, 20BP...pressure sensor (boom bottom), 20RP...pressure sensor (boom rod), 20S, 21S, 22S, 30S...IMU (inertial measurement unit), 21...arm, 21A...arm cylinder, 21BP...pressure sensor (arm bottom), 21RP...pressure sensor (arm rod), 22...bucket, 22A...bucket cylinder, 22BP...pressure sensor (bucket bottom), 22RP...pressure sensor (bucket rod), 31...main frame, 32...driving Room, 33... operation device, 34... main controller, 35... drive device, 36... prime mover (36a... engine, 36b... hydraulic pump), 37... turning load measuring device, 41... travel motor, 45... track, 100... setting input / display device, 200... attitude detection device, 250... position measurement device, 310... attitude calculation unit, 320... target surface distance calculation unit, 330... required speed calculation unit, 340... estimated toe movement trajectory calculation unit, 350... target surface interference determination unit, 360... required speed holding unit, 370... memory unit, 400... speed limit coefficient calculation unit, 410... target speed calculation unit, 430... operation command value calculation unit, 2000... construction surface management device, A22B, B22C... link

Claims

1. A running body, an upper rotating body provided rotatably relative to the traveling body; a working device attached to the upper rotating body and having a bucket that can swing freely at least in the vertical direction; actuators that drive the upper rotating body and the working device; an operating device for operating the actuator; an operation amount detection device that detects an operation amount of the operation device; an attitude detection device that detects the attitudes of the upper rotating body and the working device; a target surface setting device for setting a target surface to be excavated by the bucket; a control device that calculates a required movement direction and a required movement speed for the bucket based on the operation amount detected by the operation amount detection device, and calculates an operation command value for the actuator based on the required movement direction so that the bucket does not exceed the target surface; a drive device that drives the actuator based on an operation command value of the control device, The control device calculating an estimated movement trajectory of the tip of the bucket based on the attitude of the working device and the required movement direction, and calculating a positional relationship between the target surface and the estimated movement trajectory; When it is determined that the estimated movement trajectory intersects with the target surface based on the calculated positional relationship, and a value based on a component of the required operation speed that is perpendicular to the target surface and a distance between the toe of the bucket and the target surface does not satisfy a specific value, control is executed to limit the toe speed of the bucket while maintaining the required operation direction, or control is executed to calculate a target toe speed based on a resultant vector direction of the required operation direction and an actual toe speed vector calculated using a value acquired from the attitude detection device, a control unit that controls a tip speed of the bucket based on a tip speed that is based on an operation signal output by the operation device when it is determined from the calculated positional relationship that the estimated movement trajectory does not intersect with the target surface.

2. 2. The work machine according to claim 1, The control device A work machine comprising: a work implement; a work implement mass sensor configured to detect a mass of the work implement; a work implement control unit configured to correct the actual toe velocity vector;

3. The work machine according to claim 1 or 2, The control device setting an effective length of the estimated movement trajectory to a predetermined value that is determined in advance with the tip of the bucket as a starting point; A work machine characterized in that a positional relationship between the target surface and the estimated movement trajectory is calculated within the range of the effective length.

Images