Work machine

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 working machine.

Background Art

[0002] As a working machine used in road construction, building construction, civil engineering, dredging work, etc., a multi-joint working front is swingably attached in the vertical direction to a working machine body in which a revolving body is rotatably attached to the upper part of a traveling body that travels by a power system, and each front member constituting the working front is driven by a cylinder. As an example, there is a so-called hydraulic excavator having a working front composed of a boom, an arm, a bucket, etc. Further, in this type of hydraulic excavator, a so-called machine control is performed in which a construction target surface to be excavated is set in advance, and boom operation and the like are automatically controlled according to the operation amount of the operator's arm movement so that the bucket can excavate along the construction target surface. [[ID=I3]]

[0003] Machine control is a semi-automatic control function in which a controller controls the front operation and an operator manually operates, so in addition to control accuracy, operator operability is also emphasized. As a conventional technique related to machine control, for example, those described in Patent Document 1 and Patent Document 2 are known.

[0004] Patent Document 1 discloses a control system for a construction machine that relaxes the speed limit of an arm in which the operator's operation intention is strongly expressed in an excavation scene by limiting the speed of the boom rather than the arm when calculating the limit speed of the working device from the target surface distance and the target speed of the working tool, and suppresses the operator's discomfort.

[0005] Patent Document 2 discloses a working machine that determines whether a working tool may enter a target surface based on a set target surface and signals from a position sensor and an attitude sensor, and when it is determined that the working tool cannot enter the target surface, controls so as not to decelerate the speed even when the position of the working tool is close to the target surface, grasps the operator's intention to move the working tool quickly in the vicinity of the excavation surface, avoids restrictions on the arm, and reduces the operator's sense of discomfort.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, in the prior art described in Patent Document 1, since the restricted speed is calculated according to the distance of the working tool from the target surface, even if the trajectory of the moving tool tip cannot deviate from the target surface in the vicinity of the target surface, the operating speed is restricted, which may deteriorate the operability by being in a state contrary to the operator's intention to move quickly.

[0008] In the prior art described in Patent Document 2, since it determines whether entry is possible based on the attitude state and the input state of the operation lever, and determines whether the working device can be restricted, when an input that may suddenly cause entry is made in a state where it is determined that entry is not possible and the speed is not restricted, a sudden deceleration operation is required, and there is a risk of deviating from the target surface without being able to stop the operation, or a shock due to sudden deceleration may occur, which may impair the operability and workability of the operator.

[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 can ensure good operability by not performing unnecessary speed limit when there is no possibility of deviating from the target surface, and by appropriately performing deceleration and stop control even when the state changes to a state where deviation from the target surface is assumed.

Means for Solving the Problems

[0010] This application includes a plurality of means for solving the above problems. For example, a traveling body, an upper swing body rotatably provided with respect to the traveling body, a working device attached to the upper swing body and having a bucket that can swing at least in the vertical direction, an actuator that drives the upper swing body and the working device respectively, an operating device that operates the actuator, an operating amount detection device that detects the operating amount of the operating device, a posture detection device that detects the postures of the upper swing 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 operation direction for the bucket based on the operation amount detected by the operation amount detection device and calculates an operation command value of the actuator so that the bucket does not exceed the target surface based on the required operation direction, and a driving device that drives the actuator based on the operation command value of the control device. In the work machine, the control device calculates an estimated movement trajectory of the tip of the bucket based on the posture of the working device and the required operation direction, and calculates a positional relationship between the target surface and the estimated movement trajectory. When it is determined that the estimated movement trajectory intersects the target surface according to the calculated positional relationship, the tip speed of the bucket is limited while maintaining the required operation direction. When it is determined that the estimated movement trajectory does not intersect the target surface according to the calculated positional relationship, the tip speed of the bucket is controlled by the tip speed based on the operation signal output by the operating device.

Effects of the Invention

[0011] According to the present invention, when there is no possibility of deviating from the target surface, unnecessary speed limits are not imposed, and even when the state changes to a state where deviation from the target surface is assumed, appropriate deceleration and stop control can be performed, ensuring good operability.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Modes for Carrying Out the Invention

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

[0014] <Target Device> The target of the present embodiment is composed of a working machine 1 and a construction target surface. The construction target surface is a so-called three-dimensional construction target surface having information not only in the front-rear direction of the working machine 1 but also in the left-right direction. The construction target surface may be set relatively with respect to the working machine 1, or may be set in a global coordinate system based on the construction site or the earth.

[0015] <Configuration of the device> FIG. 1 is a side view schematically showing the overall configuration of a hydraulic excavator which is an example of a working machine according to the present embodiment.

[0016] As shown in FIG. 1, the working machine 1 includes a working front 2 (working device), a revolving body 3 (upper revolving body), and a traveling body 4. Note that the revolving body 3 (upper revolving body) and the traveling body 4 constitute the working machine body.

[0017] The working front 2 is configured to rotate about a connecting portion with respect to the revolving body 3, and the revolving body 3 is configured to rotate about a connecting portion with respect to the traveling body 4. The working front 2 includes a boom 20 having one end connected to the revolving body 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 revolving body 3 respectively, an arm cylinder 21A connected to the arm 21 and the boom 20 respectively, a link A22B, a link B22C, and a bucket cylinder 22A connected to the link B22C and the arm 21. These members are each configured to rotate in the vertical direction about a connecting portion. The traveling body 4 includes a traveling motor 41 and crawlers 45.

[0018] The boom cylinder 20A, the arm cylinder 21A, and the bucket cylinder 22A are each structured to expand and contract by hydraulic pressure, and can rotate the boom 20, the arm 21, and the bucket 22 respectively by the expansion and contraction. The bucket 22 can be arbitrarily replaced with an attachment (not shown) such as a grapple, a breaker, a ripper, a magnet, or a bucket with a rotary tilt.

[0019] The boom 20 and the arm 21 are each provided with an IMU (Inertial Measurement Unit) (boom) 20S and an IMU (arm) 21S for detecting the postures of the boom 20 and the arm 21. The link A22B is provided with an IMU (bucket) 22S for detecting the posture of the bucket 22. The IMU (boom) 20S, the IMU (arm) 21S, and the IMU (bucket) 22S are each composed of an angular velocity sensor and an acceleration sensor.

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

[0021] The slewing body 3 is provided with a slewing angle sensor 2S, an IMU (slewing body) 30S, a main frame 31, a cab 32, a main controller 34, a driving device 35, a prime mover 36, a slewing load measuring device 37, and a position measuring device 250.

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

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

[0024] The cab 32 is provided with an operating device 33, a setting input / display device 100, and a construction surface management device 2000.

[0025] 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 operation amount detection device is composed of an operation amount detection sensor such as an angle sensor provided on the operating lever, and is attached so as to be able to convert the target operations of the respective movable parts required by the operator into electrical signals by detecting the amount by which the operator tilts the operating lever.

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

[0027] The setting input / display device 100 is composed of a display monitor and a touch panel, and is attached so as to be able to display the posture of the working 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 to set various dimensions and masses of the work front 2.

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

[0029] As shown in Figure 2, the drive device 35 is composed of an electromagnetic control valve and a direction switching valve, and is attached so as to operate the boom cylinder 20A, arm cylinder 21A, and bucket cylinder 22A, which are drive actuators, by driving the electromagnetic control valve and the direction switching valve according to the operation command value instructed from the main controller 34.

[0030] The prime mover 36, which is a power source, is composed of an engine 36a and a hydraulic pump 36b connected to the output shaft of this engine 36a. More specifically, it is attached so that the hydraulic pump 36b is driven by the power of the engine 36a, and the hydraulic oil discharged by the hydraulic pump 36b generates the power required for the operation of the working machine 1.

[0031] The swing load measurement device 37 consists 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 traveling body 4 is equipped with crawlers, and the operator can move the working machine 1 by operating the operating device 33. The traveling body 4 is not limited to being equipped with crawlers, and may be equipped with traveling wheels made of tires. In addition, in this embodiment, a working machine that can move with the traveling body 4 has been exemplified and described, but it is not limited to this, and for example, it may be fixed at a construction site.

[0033] The configuration of the working machine 1 is an example, and those having the same devices and configurations may be used.

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

[0035] As shown in Figure 3, an operating 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 are connected to the main controller 34 provided in the working machine 1.

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

[0037] A prime mover 36 and an actuator 2ACT are connected to the drive device 35.

[0038] <Detailed configuration and functions of the device> <Operating device 33> The operating device 33 is composed of an operating lever, and an operation amount detection device for detecting the amount by which the operating lever is tilted is provided. The operation amount (i.e., the tilting amount) of the operating lever by the operator is detected by the operation amount detection device and converted into an electrical signal. In a hydraulic excavator, generally, as the amount by which the lever is tilted increases, the operating speed of the actuator is set to increase, and the operator changes the amount by which the lever is tilted to change the operating speed of each actuator and operate the working machine. Note that the operating device 33 may be of a hydraulic pilot type or a remotely operable type as long as it has an equivalent function.

[0039] <Posture detection device 200> The posture detection device 200 is provided with an angular velocity sensor and an acceleration sensor in each of the IMU (swivel body) 30S, IMU (boom) 20S, IMU (arm) 21S, and IMU (bucket) 22S, and further includes a swivel angle sensor 2S. Posture information of the working machine 1 can be obtained from these IMUs and angle sensors. Since the boom 20, arm 21, bucket 22, boom cylinder 20A, arm cylinder 21A, bucket cylinder 22A, link A 22B, link B 22C, and swivel body 3 are each attached so as to be swingable, the postures of the boom 20, arm 21, bucket 22, and swivel body 3 can be estimated from the mechanical link relationship. Note that the posture detection method shown here is an example, and it may be possible to directly measure the relative angles of each part of the work front 2, or to detect the strokes of the boom cylinder 20A, arm cylinder 21A, and bucket cylinder 22A to calculate the postures of each part of the working machine 1.

[0040] <Position measurement device 250> The position measurement device 250 includes a GNSS (Global Navigation Satellite System), a laser rangefinder, and a total station. As long as the position of the working machine 1 can be specified, a position measurement device other than the above may be provided.

[0041] <Drive device 35> The drive device 35 is composed of an electromagnetic control valve and a direction switching valve, and controls the amount of pressure oil supplied to the cylinders and hydraulic motors that drive each part of the working machine according to the operation command value commanded by the main controller 34. The operation command value output from the main controller 34 is converted into a pilot pressure by the electromagnetic control valve, and the direction switching valve that controls the operation amount of the actuator by the pilot pressure is driven. The hydraulic oil with adjusted flow rate by the direction switching valve is supplied to the cylinders and hydraulic motors that drive each part of the working machine to drive each movable part. In addition, by adding or changing the configuration, attachments and devices not included in the above can be additionally driven.

[0042] <Prime mover 36> The prime mover 36 is composed of an engine and a hydraulic pump, and generates the hydraulic pressure required for the operation of the working machine 1 as power. In addition to the above, a motor driven by electricity may be used to extract the hydraulic source.

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

[0044] <Construction surface management device 2000> The construction surface management device 2000 can set and manage the construction target surface for the working machine 1 using the setting input / display device 100. In addition to a single plane, the construction target surface can be set to have a plurality of planes, and the range that the work front 2 can excavate can be set. The construction target surface may be set relatively with respect to the working machine 1, or may be set in a coordinate system based on the construction site or the earth.

[0045] <Setting input / display device 100> The setting input / display device 100 can display the posture of the working machine 1, the 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, etc. to the operator.

[0046] <Main Controller 34> As shown in FIG. 3, the main controller 34 is connected to the operating 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 bucket tip 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 working machine 1 based on the information from the attitude detection device 200.

[0048] The target surface distance calculation unit 320 calculates the distance from the construction target surface (hereinafter referred to as the target surface distance) using the attitude and position information of the working machine 1.

[0049] The required speed calculation unit 330 calculates the operating speed required for the working machine 1 using the attitude of the working machine 1 and the operator's operation amount.

[0050] The estimated bucket tip movement trajectory calculation unit 340 calculates the estimated bucket tip movement trajectory (hereinafter referred to as the movement trajectory) by estimating the movement of the bucket tip using the attitude and required speed of the working machine 1.

[0051] The target surface interference determination unit 350 determines whether the bucket tip 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 memory unit 370 consists 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 34.

[0054] The speed limit coefficient calculation unit 400 calculates a speed limit coefficient for correcting the required speed according to the attitude information of the working machine 1, the target surface distance, the required holding speed, and the target surface interference determination result.

[0055] The target speed calculation unit 410 calculates the target speed of the actuator 2ACT according to the attitude information of the working 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 drive device 35 based on the target speed of the actuator 2ACT calculated by the target speed calculation unit 410.

[0057] <Operation and calculation method of the device> <Operation of machine control> In machine control, the controller controls the operation of the working machine 1 so that the working tool of the working machine 1 driven based on the operator's operation does not dive into the construction target surface. For example, when trying to operate the front toward the target surface and perform excavation with the bucket, the front speed is decelerated from the stage of approaching to bring the tip of the bucket closer to the target surface so that the tip position of the bucket does not deviate from the target surface. When there is a tip on the target surface, the front operation is restricted so that it does not move further below the target surface. This control is implemented by calculating the required speed of the operator that quantitatively gives the operation required by the operator and calculating the target speed based on the calculation result of the speed limit coefficient.

[0058] <Calculation method of required speed: Required speed calculation unit 330> As one method of calculating the required operation of the operator, there is a method of calculating a required speed vector based on the lever operation amount. Since all of the working machines 1 are mechanically connected and the operation of the actuator corresponds one-to-one to the lever operated by the operator, the lever operation amount can be obtained as the speed of each actuator, that is, the required speed. Therefore, for example, it is possible to express as a vector how much and in which direction the tip of the bucket 22 (hereinafter simply referred to as the tip) moves with respect to the lever operation amount.

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

[0060] In the case shown in Figure 4, the vector points to a dotted arrow extending obliquely downward to the right from the claw 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, defined by a dotted arrow extending to the right from the claw tip, and a speed component V_z perpendicular to the construction target surface, defined by a dotted arrow extending downward from the claw 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, except in an emergency, a maximum value is set for the time change amount of the required speed so that acceleration and deceleration can be performed smoothly, and a value that does not exceed this is used. In this way, an operation that conforms to the operator's intuition that a large 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 claw 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 velocity limit coefficient of the z-component is a dimensionless quantity calculated based on the required velocity component V_z perpendicular to the construction target surface and the target surface distance d, and is defined by b_z. Here, the closer the value of b_z is to 0, the stronger the velocity limit acts; the closer the value of b_z is to 1, the weaker the velocity limit acts; when b_z takes the value of 1, it means that no velocity limit acts. Further, as shown in the following (Equation 1), (Equation 2), and (Equation 3), at d = 0, b_z = 0; at a certain target surface distance d1, b_z = 1. When d exceeds 0 and is less than d1, as d increases, b_z also has a larger value in the range of exceeding 0 and less than 1 (that is, the change rate b_z' of b_z with respect to d has a positive value). When d is greater than or equal to d1, b_z has a constant value of 1. Generally, as V_z increases, d1 takes a larger value. However, if the working tool of the working machine 1 operates without diving into the construction target surface, d1 can take any value. When b_z calculated by the above method is finally transmitted to the target velocity calculation, the control is called "deceleration control".

[0064] d = 0; b_z = 0 …(Equation 1) 0 < d < d1; 0 < b_z < 1 and b_z' > 0 …(Equation 2) d >= d1; b_z = 1 …Equation (3) Note that b_z calculated by the deceleration control may be rejected depending on the positional relationship between the target surface and the movement trajectory described later, and may be defined by another value that is 0 or more and 1 or less.

[0065] <Calculation method of the velocity limit coefficient of the x-component in deceleration control: Velocity limit coefficient calculation unit 400> The velocity limit coefficient b_x of the x-component is calculated as shown in the following (Equation 4) by the velocity limit coefficient b_z of the z-component calculated by the above method.

[0066] b_x = b_z …(Equation 4) Note that b_z calculated by the deceleration control may be rejected depending on the positional relationship between the target surface and the movement trajectory described later, and may be defined by another value that is 0 or more and 1 or less.

[0067] <Calculation method of movement trajectory: Estimated bucket tip movement trajectory calculation unit 340> The movement trajectory is defined by the current posture of the working machine 1 and the x-component V_x and z-component V_z of the required speed. 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 working machine 1, the operation amount ratio of the boom and arm for realizing θ is uniquely determined. Here, assuming that the working machine 1 operates while keeping the operation amount ratio constant hereafter, as shown in FIG. 4, a trajectory that is convex downward passes through the current bucket tip. Such a trajectory is defined as the "estimated movement trajectory".

[0069] Note that the movement trajectory may be defined over the entire movable range of the boom and arm of the working machine 1, or a certain effective length β may be defined separately and defined within that range. Also, if the movement trajectory can be estimated more accurately by a method other than the above method, the movement trajectory may be defined by that method. As the effective length β, for example, it is conceivable to define the shorter one among the length predicted until a predetermined time and the length predicted until the end of the movable range. Also, it is conceivable to determine the effective length β in consideration of the surrounding environment and calculation cost at the time of prediction.

[0070] <Calculation method of the positional relationship between the construction target surface and the movement trajectory: Target surface interference determination unit 350> As shown in FIG. 4, the movement trajectory may not have an intersection with the construction target surface, or as shown in FIG. 5, it may have an intersection with the construction target surface. Such a positional relationship between the construction target surface and the movement trajectory can be determined as follows. For example, assuming a two-dimensional plane model and defining the construction target surface as a straight line of z = 0, if the positive and negative of the z-coordinate of the entire movement trajectory are always constant, it has no intersection with the construction target surface, and if the positive and negative switch, it has an intersection with the construction target surface.

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

[0072] <Definition and calculation method of restriction release control> When it is determined by the calculation of the positional relationship that the construction target surface and the movement trajectory do not intersect with each other as shown in FIG. 4, the value of the velocity limit coefficient b_z in the z component calculated by the deceleration control is rejected, and instead, b_z = 1 is applied. At the same time, the value of the velocity limit coefficient b_x in the x component is also applied as b_x = 1.

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

[0074] State 1: Regardless of the relationship between the construction target surface and the movement trajectory, when d >= d1 State 2: When the construction target surface and the movement trajectory do not intersect with each other and d < d1 In (State 1), it is defined as being in the "deceleration control" state, and in (State 2), it is defined as being in the "restriction release control" state. "Restriction release control" is characterized in that, if the claw tip speed of the bucket is controlled only by the magnitude of the target surface distance d and a target speed smaller than the required speed has been calculated, 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 required speed.

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

[0076] State 3: When the construction target surface and the movement trajectory intersect with each other and d < d1 In the situation of switching from (State 1) to (State 3), deceleration control may be continuously implemented. However, in the situation of switching from (State 2) to (State 3), as shown in FIG. 8, the time changes of b_x and b_z become extremely large, and there is a concern that the control will not be in time and the bucket will interfere with the control target surface. Therefore, calculations for reducing the risk are performed by the method described later.

[0077] <Definition of the holding toe speed vector: Required speed holding unit 360> In the control state of restriction release, assuming a situation where the state switches from (state 2) to (state 3), in order to cope with the calculation method described later, the current required speed is recorded in the required speed holding unit. Based on the recorded required speed, what is configured as a speed vector is called the holding toe speed vector V_hold.

[0078] <Calculation method when the movement trajectory switches from the control state of restriction release to a state where it interferes with the target surface> In the control state of restriction release, when switching from (state 2) to (state 3), it is defined as "deviation from restriction release". In the state of "deviation from restriction release", as shown in Fig. 9, the combined vector direction Φ defined by the vector V+V_hold obtained by combining the current toe speed vector V and the holding toe speed vector V_hold held in the required speed holding unit is calculated. Furthermore, the speed limit coefficient b_z of the z component is determined by, for example, any of the above (Equation 1), (Equation 2), and (Equation 3), and the speed limit coefficient b_x of the x component is calculated based on Φ and the required speed V of the x component. Note that b_z may be determined by another method if the construction target surface does not interfere with the bucket.

[0079] <Calculation method of the target speed> The x component V_xlim of the target speed V_lim is calculated as follows in the following (Equation 6) by the speed limit coefficient b_x of the x component and the x component V_x of the required speed V, and the z component V_zlim of the target speed V_lim is calculated as follows in the following (Equation 7) by the speed limit coefficient b_z of the z component and the z component V_z of the required speed V.

[0080] V_xlim = b_x × V_x …(Equation 6) V_zlim = b_z × V_z …(Equation 7) The calculation and operation examples are shown in FIG. 9. For example, when the moving trajectory is in a positional relationship where it has no intersection with the construction target surface, the above (Equation 4) holds, and V_xlim becomes equal to V_x, and V_zlim becomes equal to V_z respectively. Also, assuming that if it corresponds to (State 2), the target speeds V_xlim' and V_zlim' in the case where the bucket tip speed is controlled only by the magnitude of the target surface distance d are also potentially calculated, but are actually rejected.

[0081] Next, consider the case where the required speed V changes and switches to (State 3). In the prior art, since the target speed is given in the vector direction equal to the required speed vector, the moving trajectory does not change due to control. Therefore, when switching to (State 3) in a state where the target surface distance d is small, there is a risk that the control will not be in time and the bucket will interfere with the construction target surface. On the other hand, in the present invention, the target speeds V_xlim and V_zlim are given in the vector direction equal to the vector direction Φ defined by the vector V + V_hold obtained by synthesizing the current tip speed vector V and the held tip speed vector V_hold held in the required speed holding unit, thereby changing the moving trajectory and reducing the risk.

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

[0083] As shown in FIGS. 6 and 7, first, the main controller 34 acquires and calculates the posture of the work machine (step S100), acquires and calculates the information of the construction target surface (step S110), acquires and calculates the operation amount by the operator (step S120), calculates the required speed by the operator (step S130), calculates the estimated tip movement trajectory (step S140), calculates the positional relationship between the construction target surface and the estimated tip movement trajectory (step S150), and temporarily calculates the speed limit coefficient b_z of the z component according to the target surface distance d (step S160).

[0084] Here, it is determined whether there is an intersection between the construction target surface and the estimated tip movement locus (step S170).

[0085] If the determination result in step S170 is YES, that is, if it is determined that an intersection exists, then subsequently, it is determined whether the velocity limit 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 velocity limit coefficient b_z is other than 1, then subsequently, it is determined whether the control mode at the time when the processing shown in FIGS. 6 and 7 was last executed was deceleration control (step S200). In addition, when the calculation has not been performed immediately before, such as at the start, it is determined assuming that it was deceleration control.

[0087] If the determination result in step S200 is YES, then the velocity limit coefficient b_z of the z component temporarily calculated in step S160 is applied as the value to be passed to the target calculation unit, and further, the velocity limit coefficient b_x of the x component is set to the same value as b_z (step S220), and subsequently, it is determined that deceleration control is in progress (step S230).

[0088] Also, if the determination result in step S200 is NO, that is, if deceleration control was not performed at the time of the previous calculation, then the holding tip velocity vector and the current tip velocity vector are synthesized, and the vector direction Φ is calculated (step S240). The velocity limit coefficient b_z of the z component temporarily calculated in step S160 is applied as the value to be passed to the target calculation unit, and further, the velocity 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 process is in the deviation process with restriction released (step S260).

[0089] Also, when the determination result in step S170 is NO (i.e., when it is determined that there is no intersection), or when the determination result in step S180 is YES (i.e., when the speed limit coefficient b_z is 1), the speed limit coefficients b_x and b_z of each of the x and z components are set to 1 (step S190). Subsequently, it is determined whether the temporarily calculated speed limit coefficient of the z component is 1 (step S210).

[0090] When the determination result in step S210 is YES, i.e., when the speed limit coefficient b_z is 1, it is determined that deceleration control is in progress (step S270).

[0091] Also, when the determination result in step S210 is NO, i.e., when the speed limit coefficient b_z is other than 1, the holding fingertip speed vector is updated to the current fingertip speed vector (step S280), and it is determined that control for releasing the restriction is in progress (step S290).

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

[0093] Subsequently, an operation command value for operating the working machine is calculated (step S310), the operation command value is transmitted to the drive device (step S320), and the process ends.

[0094] <Effects of the Present Embodiment> As described above, according to the present embodiment, when there is no possibility of deviating from the target plane even in the vicinity of the target plane, the bucket can be moved in the direction intended by the operator without performing unnecessary speed limitation, and even when switching to a state where deviation from the target plane is assumed, it is possible to appropriately shift to a deceleration / stop control state, so that good operability can be ensured.

[0095] <Others> Note that the present invention is not limited to the above-described embodiments, and various modifications within the scope not departing from the gist thereof are included. Further, for example, the present invention is not limited to having all the configurations described in the above embodiments, and also includes those in which a part of the configuration is deleted. Further, it is possible to add or replace a part of the configuration according to a certain embodiment with the configuration according to another embodiment. Further, each configuration related to the above control device, the functions and execution processes of the respective configurations, etc. may be realized in part or in whole by hardware (for example, designing the logic for executing each function with an integrated circuit). Further, the configuration related to the above control device may be a program (software) in which each function related to the configuration of the control device is realized by being read and executed by an arithmetic processing device (for example, a CPU). Information related to the program can be stored in, for example, a semiconductor memory (flash memory, SSD, etc.), a magnetic storage device (hard disk drive, etc.), and a recording medium (magnetic disk, optical disk, etc.).

Explanation of Signs

[0096] 1... Working machine, 2... Working front, 2ACT... Actuator, 2S... Swivel angle sensor, 3... Swiveling 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... Cab, 33... Operating device, 34... Main controller, 35... Driving device, 36... Prime mover (36a... Engine, 36b... Hydraulic pump), 37... Swivel load measuring device, 41... Traveling motor, 45... Crawler, 100... Setting input / display device, 200... Attitude detection device, 250... Position measuring device, 310... Attitude calculation unit, 320... Target surface distance calculation unit, 330... Required speed calculation unit, 340... Estimated tip 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 traveling body, An upper slewing body provided rotatably with respect to the traveling body, A working device attached to the upper slewing body and having a bucket that can swing at least in the vertical direction, Actuators for driving the upper slewing body and the working device respectively, An operating device for operating the actuators, An operation amount detection device for detecting the operation amount of the operating device, An attitude detection device for detecting the attitudes of the upper slewing 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 operation direction for the bucket based on the operation amount detected by the operation amount detection device, and calculates an operation command value for the actuator so that the bucket does not exceed the target surface based on the required operation direction, In a working machine having a driving device for driving the actuator based on the operation command value of the control device, The control device, Based on the attitude of the working device and the required operation direction, calculates an estimated movement locus of the tip of the bucket and calculates a positional relationship between the target surface and the estimated movement locus, When it is determined that the estimated movement locus intersects the target surface according to the calculated positional relationship, the tip speed of the bucket is limited while maintaining the required operation direction, When it is determined that the estimated movement locus does not intersect the target surface according to the calculated positional relationship, the tip speed of the bucket is controlled by the tip speed based on the operation signal output by the operating device. A working machine characterized by this.

2. In the working machine according to Claim 1, The control device, When it is determined that the estimated movement locus does not intersect the target surface and the tip speed is controlled based on the operation signal output by the operating device, and when the estimated movement locus changes to a state of intersecting the target surface, the required operation direction and the actual tip speed vector calculated from the value obtained from the attitude sensor A working machine characterized by calculating a tip target speed based on the direction of the composite vector.

3. In the working machine according to Claim 2, The control device, Corrects the actual tip speed vector using a correction value calculated based on the mass of the working device. A working machine characterized by this.

4. In the working machine according to any one of Claims 1 to 3, The control device, Set the effective length of the estimated movement trajectory to a predetermined value starting from the tip of the claw of the bucket. An operating machine, characterized by calculating the positional relationship between the target surface and the estimated movement trajectory within the range of the effective length.

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