Working machinery

Abstract

To prevent the control device from exceeding its allowable computational load and to suppress a decrease in control accuracy. [Solution] The drive control device includes: an motion generation unit that generates a target motion of the front work device using parameters based on the detection result of the attitude sensor and work design information; an actuator control unit that calculates the target operating speed of the actuator based on the target motion generated by the motion generation unit and generates and outputs a control signal to control the operation of the actuator at the calculated target operating speed; a computation load estimation unit that estimates the computation load of the drive control device based on the calculation time of the target motion in the motion generation unit, the calculation time of the target operating speed in the actuator control unit, and the load of the overall control device; and a parameter adjustment unit that adjusts the parameters to reduce the computation load of the motion generation unit if it is determined that the computation load estimated by the computation load estimation unit is higher than a predetermined reference value.

Description

Technical Field

[0001] The present invention relates to a working machine.

Background Art

[0002] With the response to informatized construction, machine guidance that displays the position and posture of working devices such as booms, arms, and buckets (working tools) to an operator, and machine control (operation support control) that controls the position of the working device to move along a target construction surface, are developed. Machine control contributes to improving construction accuracy by avoiding over-excavation of the target excavation surface when the control system intervenes in the operator's operation. On the other hand, there is concern that the calculation load of the controller increases with the addition of these functions. In particular, for a control system that utilizes model predictive control (MPC: Model Predictive Control), which is known for its high calculation load, for example, the technology of Patent Document 1 is known for the purpose of reducing the calculation load.

[0003] Patent Document 1 discloses a control device for an internal combustion engine that performs idle speed control to control the rotational speed during idle operation of the internal combustion engine to a predetermined idle rotational speed, having a multi-core processor equipped with a plurality of cores, an arithmetic means for allocating various arithmetic tasks related to the operation of the internal combustion engine to the plurality of cores and performing arithmetic operations in parallel, and a control means for reducing the number of cores used for the arithmetic means compared to before when stopping the idle speed control.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the conventional technology described above, the computational load is reduced by optimally allocating cores according to the computational load of the internal combustion engine. However, if the allowable computational load of a core is limited, or if the number of cores is limited, the computational load of the control device may exceed the allowable computational load (hereinafter, this phenomenon will be referred to as task overrun). If a task overrun occurs, real-time control becomes difficult, and it may not be possible to achieve the expected control accuracy.

[0006] The present invention has been made in view of the above, and aims to provide a work machine that can prevent the computational load in the control device from exceeding the allowable computational load and suppress a decrease in control accuracy. [Means for solving the problem]

[0007] The present invention includes multiple means for solving the above problems, but to give one example, a work machine comprising: a lower traveling body; an upper rotating body rotatably mounted relative to the lower traveling body; a multi-jointed front working device mounted on the upper rotating body and having a working tool at its tip; actuators for driving the lower traveling body, the upper rotating body, and the front working device, respectively; a posture sensor for detecting posture information which is information relating to the posture of the upper rotating body and the front working device; and a drive control device which acquires predetermined work design information relating to work and design by the front working device and controls the actuator based on the detection result of the posture sensor so that the working tool of the front working device operates according to the work design information, wherein the work machine is further equipped with a control load measuring device for measuring the load of an overall control device that controls the overall operation of the work machine including the drive control device, and the drive control The device comprises: a motion generation unit that generates a target motion of the front work device using parameters based on the detection result of the attitude sensor and the work design information; an actuator control unit that calculates the target operating speed of the actuator based on the target motion generated by the motion generation unit and generates and outputs a control signal to control the operation of the actuator at the calculated target operating speed; a calculation load estimation unit that calculates the calculation time of the target motion in the motion generation unit and the calculation time of the target operating speed in the actuator control unit and estimates the calculation load of the drive control device based on the two calculated calculation times and the load of the overall control device measured by the control load measuring device; and a parameter adjustment unit that adjusts the parameters to reduce the calculation load of the motion generation unit if it is determined that the calculation load estimated by the calculation load estimation unit is higher than a predetermined reference value. [Effects of the Invention]

[0008] According to the present invention, it is possible to prevent the control device from exceeding its allowable computational load and to suppress a decrease in control accuracy. [Brief explanation of the drawing]

[0009] [Figure 1]This is a schematic perspective view showing the appearance of a hydraulic excavator, which is an example of a type of construction machinery. [Figure 2] This is a functional block diagram that schematically shows some of the processing functions of the control system installed in a hydraulic excavator. [Figure 3] This figure shows an example of table data illustrating the relationship between the computational load of the motion generation unit and the number of computation attempts. [Figure 4] This figure shows the relationship between parameters related to the computational load of the MPC in the motion generation unit. [Figure 5] This figure shows the time variation of the allowable computational load, the computational load of the control device, and the actual allowable computational load. [Figure 6] This is a flowchart showing the processing steps of the control device. [Figure 7] This is a schematic functional block diagram showing some of the processing functions of a control device mounted on a hydraulic excavator according to the first embodiment. [Figure 8] This diagram provides a schematic overview of the intrusion / deviation detection process. [Figure 9] This diagram provides a schematic overview of the intrusion / deviation detection process. [Figure 10] This is a flowchart showing the processing content of the control device according to the second embodiment. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings. In the embodiments of the present invention, a hydraulic excavator equipped with a front working device will be used as an example of the working machine, but the present invention can also be applied to other working machines equipped with working devices such as wheel loaders and cranes.

[0011] Furthermore, in the following explanation, when multiple identical components exist, an alphabet letter may be added to the end of the code (number), but this alphabet letter may be omitted, and the multiple components may be referred to collectively. That is, for example, when there are four attitude sensors (attitude sensors 26A, 26B, 26C, 26D), they may be referred to collectively as attitude sensor 26. Also, for simplicity, diagrams may be omitted for signal lines, etc., whose connection relationships are clear from the explanation.

[0012] <First Embodiment> A first embodiment of the present invention will be described with reference to Figures 1 to 6.

[0013] Figure 1 is a schematic perspective view showing the external appearance of a hydraulic excavator, which is an example of a work machine according to this embodiment. Figure 2 is a schematic functional block diagram showing some of the processing functions of the control device mounted on the hydraulic excavator.

[0014] In Figure 1, the hydraulic excavator 100 (working machine) comprises a multi-jointed front working device 24, which is composed of multiple driven members (boom 8, arm 9, bucket 10 (working tool)) that rotate vertically, and an upper slewing body 22 and a lower traveling body 20 that constitute the vehicle body. The upper slewing body 22 is provided to be rotatable relative to the lower traveling body 20 via a slewing mechanism 21. The slewing mechanism 21 has a slewing motor 23 and a posture sensor 26D (vehicle body slewing angle detection device). The slewing motor 23 drives the upper slewing body 22 to slewing relative to the lower traveling body 20, and the posture sensor 26D detects the slewing angle relative to the lower traveling body 20, and the detection result is output as posture information.

[0015] The proximal end of the boom 8 of the front working device 24 is supported so as to be vertically rotatable at the front part of the upper swing body 22. One end of the arm 9 is supported so as to be vertically rotatable at an end (tip) different from the proximal end of the boom 8, and a bucket 10 is supported so as to be vertically rotatable at the other end of the arm 9. The boom 8, the arm 9, the bucket 10, the upper swing body 22, and the lower traveling body 20 are respectively driven by a boom cylinder 5, an arm cylinder 6, a bucket cylinder 7, a swing motor 23, and left and right traveling motors 3a, 3b (however, only one traveling motor 3a is shown in the figure, and the other traveling motor 3b is indicated only by a symbol in parentheses), which are hydraulic actuators.

[0016] Here, a vehicle body coordinate system is set with the intersection of the swing center axis 25 of the upper swing body 22 and the lower surface of the upper swing body 22 as the origin, a z-axis with the upward direction along the swing center axis 25 being positive, an x-axis with the front direction in the front-rear direction perpendicular to the z-axis from the origin being positive, and a y-axis with the right direction in the left-right direction perpendicular to the z-axis and the x-axis from the origin being positive.

[0017] On the front left side of the upper swing body 22, a cab 2 for the operator to board is mounted. Also, on the upper swing body 22, a control device 28 (drive control device) for controlling the operation of the hydraulic excavator 100, a work design information storage device 29 to be described later, and a controller load measurement device 45 are arranged, and an overall control device 101 is configured with each functional part for performing the overall operation control of the hydraulic excavator 100. In the cab 2, there are provided operation levers 2a, 2b (operation devices) for outputting operation signals (operation commands) for operating the boom cylinder 5, arm cylinder 6, bucket cylinder 7, and swing motor 23 (hereinafter sometimes referred to as hydraulic actuators 5, 6, 7, 23), a display device 36 (described later) such as a monitor for presenting and notifying various information to the operator, etc. Although not shown in the figure, the operation levers 2a, 2b can be tilted forward, backward, left, and right respectively, and include a detection device not shown in the figure for electrically detecting the tilt amount of the lever, that is, the lever operation amount, and the lever operation amount detected by the detection device is output to the control device 28 via electrical wiring. That is, the operation of the hydraulic actuators 5, 6, 7, 23 is respectively assigned to the front-rear direction or left-right direction of the operation levers 2a, 2b. Also, although not shown in the figure, the cab 2 is provided with a travel operation lever (travel pedal) for operating the travel motors 3a, 3b, and the lever operation amount of the travel operation lever detected electrically is output to the control device 28 via electrical wiring.

[0018] The operation control of the boom cylinder 5, arm cylinder 6, bucket cylinder 7, swing motor 23, and the left and right travel motors 3a, 3b (hereinafter sometimes referred to as hydraulic actuators 3a, 3b) is performed by controlling the direction and flow rate of the hydraulic oil supplied from a hydraulic pump device driven by a prime mover such as an engine or an electric motor not shown in the figure to each hydraulic actuator 3a, 3b, 5, 6, 23 with a control valve or the like. The control valve is operationally controlled by the control device 28 based on the operation signals from the operation levers 2a, 2b and the travel operation lever, and thereby the operations of each hydraulic actuator 3a, 3b, 5, 6, 7, 23 are controlled.

[0019] Attitude sensors 26A, 26B, and 26C are attached to the base of the boom 8, the connection point between the boom 8 and the arm 9, and the connection point between the arm 9 and the bucket 10, respectively. Attitude sensors 26A, 26B, and 26C are mechanical angle sensors, such as potentiometers, and output the detection results as attitude information. Attitude sensor 26A measures the angle between the longitudinal direction of the boom 8 (the straight line connecting the pivot centers at both ends) and the xy-plane and transmits it to the control device 28. Similarly, attitude sensor 26B measures the angle between the longitudinal direction of the boom 8 (the straight line connecting the pivot centers at both ends) and the longitudinal direction of the arm 9 (the straight line connecting the pivot centers at both ends) and transmits it to the control device 28. Likewise, attitude sensor 26C measures the angle β3 between the longitudinal direction of the arm 9 (the straight line connecting the pivot centers at both ends) and the longitudinal direction of the bucket 10 (the straight line connecting the pivot center and the toe) and transmits it to the control device 28. As described above, the attitude sensors 26A, 26B, 26C, and 26D detect attitude information of the upper rotating body 22 and the front work device 24 and transmit it to the control device 28.

[0020] In this embodiment, the pivot center of the front work device 24 (the connection point with the upper rotating body 22 of the boom 8) is described as being located at a different position from the pivot axis 25, but the pivot center may be arranged so as to intersect with the pivot axis 25.

[0021] Furthermore, in this embodiment, an example was described in which angle sensors or rotation angle sensors are used as attitude sensors 26A, 26B, 26C, and 26D to detect the relative angles of the lower traveling body 20, upper slewing body 22, boom 8, arm 9, and bucket 10, but the embodiment is not limited to this. That is, for example, an inertial measurement unit (IMU) may be used as the attitude sensors 26A, 26B, 26C, and 26D. Alternatively, stroke sensors may be placed on the boom cylinder 5, arm cylinder 6, and bucket cylinder 7, respectively, and the relative angles at each connection point of the upper slewing body 22, boom 8, arm 9, and bucket 10 may be determined from the stroke change amount.

[0022] In Figure 2, the control device 28 includes an action generation unit 30, an actuator control unit 31, a computation load estimation unit 32, a parameter adjustment unit 33, and a warning unit 34.

[0023] The motion generation unit 30 generates target motions (motion commands) for each hydraulic actuator 5, 6, 7, and 23, such as target cylinder speed and target rotational speed, using parameters based on the posture information detected by the posture sensor 26 and the work design information pre-stored in the work design information storage device 29, and transmits them to the actuator control unit 31. The specific method for generating motion commands will be described in detail later.

[0024] The actuator control unit 31 calculates the target operating speed for operating the control valves of each hydraulic actuator 5, 6, 7, 23 based on the target operation (operation command) of each actuator 35 generated by the motion generation unit 30, and outputs it to each hydraulic actuator 5, 6, 7, 23 (more precisely, to flow control valves that control the flow rate and direction of pressurized oil supplied to each hydraulic actuator 5, 6, 7, 23 from a hydraulic pump driven by a prime mover such as an engine). At this time, the actuator control unit 31 controls the operating speed of each actuator 35 to match the target operating speed based on the response of each hydraulic actuator 5, 6, 7, 23 detected by various sensors, including the attitude sensor 26.

[0025] The computation load estimation unit 32 estimates the computation load of the control device 28 based on information related to the load of the overall control device 101 obtained from the controller load measurement device 45 (e.g., power consumption) and the computation load of the motion generation unit 30 and the actuator control unit 31. It then determines whether the estimation result is higher than a predetermined reference value and transmits the determination result to the parameter adjustment unit 33 and the warning unit 34. The specific method for estimating the computation load will be described in detail later.

[0026] The parameter adjustment unit 33 adjusts the parameters to reduce the computational load of the motion generation unit 30 based on the computational load estimation result of the control device 28 estimated by the computational load estimation unit 32. The specific method of adjusting the parameters will be described in detail later.

[0027] The alerting unit 34 determines whether an alert is necessary based on the computational load of the control device 28 estimated by the computational load estimation unit 32. If it is determined that the estimated computational load is higher than the standard value, it notifies the operator of the alert via the display device 36. The specific details of the alert notification will be described later.

[0028] <Movement generator 30> The specific method for generating operation commands in the operation generation unit 30 will be described below.

[0029] The motion generation unit 30 first calculates the toe position of the bucket 10 (work tool) based on the posture information detected by the posture sensor 26. Next, it generates a target motion based on the calculated toe position of the bucket 10 and the target position obtained as work design information from the work design information storage device 29. One method for generating the target motion is to calculate a toe velocity vector based on the toe position of the bucket 10 and the target position, and then calculate the target joint angular velocity of each hydraulic actuator 5, 6, and 7 using the inverse Jacobian matrix. On the other hand, when using Model Predictive Control (MPC), a convergence calculation is performed to calculate the control input so as to minimize the value of the evaluation function up to a predetermined time in the future (predicted horizon). For example, if the deviation between the toe position and the target position is set in the evaluation function, and the control input is calculated so as to minimize this evaluation function, it is not necessary to individually design the cylinder drive amounts related to the boom 8, arm 9, and bucket 10, and the appropriate drive amounts for the hydraulic actuators 5, 6, and 7 can be automatically calculated according to the situation. The evaluation function described above is merely one example; a different evaluation function may be used if the same reasoning is followed.

[0030] The parameters used in the motion generation unit 30 include parameters for adjusting the computation load, parameters for adjusting the operation, and parameters for adjusting (switching) the enabled / disabled state of the calculations performed by the motion generation unit 30.

[0031] Parameters related to computational load can be adjusted by the parameter adjustment unit 33. Specific parameter adjustments will be described in detail later.

[0032] The parameters that adjust the operation can be switched between prioritizing the elimination of deviations or suppressing the control input by adjusting the weight matrix.

[0033] The parameter for enabling / disabling the calculation performed by the motion generation unit 30 can be adjusted by the parameter adjustment unit 33. Specifically, when a parameter indicating "enabled" for the calculation is input from the parameter adjustment unit 33, the calculation operation to generate the target motion is started and continued, and when a parameter indicating "disabled" for the calculation is input, the calculation operation to generate the target motion is stopped. For example, if the calculation load of the motion generation unit 30 is high and there is no prospect of sufficiently reducing the calculation load of the motion generation unit 30 by adjusting the parameter for adjusting the calculation load by the parameter adjustment unit 33, a parameter indicating "disabled" for the calculation will be input from the parameter adjustment unit 33, the calculation by the motion generation unit 30 will be stopped, and the operation of the hydraulic excavator 100 will be stopped.

[0034] <Computational load estimator 32> The specific method for estimating the computational load in the computational load estimation unit 32 will be described below.

[0035] The computational load of the overall control device 101 related to the overall operation control of the work machine 100 can be broadly divided into the operation load Lc caused by the startup and operation of the overall control device 101, the communication load Lt that occurs when the overall control device 101 communicates with other systems, and the computational load Lcs of the control device 28.

[0036] When estimating the computation load Lcs of the control device 28, the computation load estimation unit 32 first calculates the rated operating load Lcu of the overall control device 101 based on the rated power consumption Wcu and the maximum power consumption Wcumax of the overall control device 101. The rated operating load Lcu of the overall control device 101 can be expressed by the following (Equation 1) using the rated power consumption Wcu and the maximum power consumption Wcumax.

[0037]

number

[0038] The maximum power consumption Wcumax of the overall control unit 101 can be determined based on the publicly available product specifications of the overall control unit 101. Furthermore, the rated power consumption Wcu of the overall control unit 101 can be obtained by experimental measurement under conditions where no communication or internal calculations are performed.

[0039] (Computational load Lcs) The method for estimating the computational load Lcs of the control device 28 will be described.

[0040] The computational load Lcs of the control device 28 is expressed as the sum of the computational load Lact of the actuator control unit 31 and the computational load Lmp of the motion generation unit 30, as shown in (Equation 2) below.

[0041]

number

[0042] As can be seen from (Equation 2) above, assuming that the computational load Lact of the actuator control unit 31 is approximately constant, the amount of change in the computational load Lcs of the control device 28 will depend on the amount of change in the computational load Lmp of the motion generation unit 30. In other words, by estimating the amount of change in the computational load Lmp of the motion generation unit 30, it becomes possible to estimate the amount of change in the computational load Lcs.

[0043] The calculation load Lmp of the motion generation unit 30 is estimated, for example, by creating a table in advance that shows the relationship between the number of calculation attempts (number of calculation attempts [No.]) until the MPC calculation converges and the calculation load Lmp of the motion generation unit 30, and then referring to this table data.

[0044] Figure 3 shows an example of table data illustrating the relationship between the computational load of the motion generation unit and the number of computation attempts. In Figure 3, the vertical axis shows the computational load Lmp[%] of the motion generation unit 30, and the horizontal axis shows the number of computation attempts[No.].

[0045] In creating the table data, first, the power consumption Wref1 of the overall control device 101 is experimentally measured under conditions where no communication is performed and the operation of the motion generation unit 30 is stopped. Then, as shown in (Equation 3) below, the power consumption Wact of the actuator control unit 31 is calculated by taking the difference between this amount and the rated power consumption Wcu of the overall control device 101.

[0046]

number

[0047] Next, with the motion generation unit 30 in operation, the power consumption Wref2 of the overall control device 101 is measured experimentally. Then, as shown in (Equation 4) below, the power consumption Wmp of the motion generation unit 30 for each calculation is calculated by taking the difference between the power consumption Wact of the actuator control unit 31 and the rated power consumption Wcu of the overall control device 101 for each calculation. This allows for the creation of table data.

[0048]

number

[0049] The power consumption Wcs of the control device 28 is expressed as the sum of the power consumption Wact of the actuator control unit 31 and the power consumption Wmp of the motion generation unit 30, as shown in (Equation 5) below.

[0050]

number

[0051] Therefore, the computational load Lact of the actuator control unit 31 and the computational load Lmp of the motion generation unit 30 are expressed by (Equation 6) and (Equation 7) below, respectively.

[0052]

number

[0053]

number

[0054] The computational load Lmp of the motion generation unit 30 is used by the parameter adjustment unit 33 when adjusting parameters related to the computational load. The adjustment of parameters using the computational load Lmp of the motion generation unit 30 will be described in detail later.

[0055] (Communication load Lt) This section describes a method for estimating the communication load Lt that occurs when the overall control unit 101 communicates with other systems.

[0056] The communication load Lt is determined by the communication cycle and the amount of data transmitted. Generally, the more data transmitted, the greater the overall communication load. Also, when communicating with multiple different communication cycles, the communication load increases most at the least common multiple of the cycles. For example, when communicating with multiple communication cycles of 1ms, 5ms, and 10ms, the communication load increases most at every 10ms cycle.

[0057] Specifically, the communication load Lt can be estimated from the current power consumption Wref3 of the overall control unit 101, the rated power consumption Wcu of the overall control unit 101, the power consumption Wcs of the control unit 28, and the maximum power consumption Wcumax using the following equation (Equation 8).

[0058]

number

[0059] (Allowable computational load La) This section explains how to determine the allowable computational load La.

[0060] The allowable computational load La is determined by the sum of the rated operating load Lcu and the communication load Lt of the overall control unit 101. For example, if the rated operating load Lcu of the overall control unit 101 is 10% and the rated communication load Lt is 20%, then the allowable computational load La is 70%. However, in practice, a margin M is generally provided so that the overall control unit 101 is not driven at its maximum load. That is, the actual allowable computational load LaMargin, including the margin M, is expressed by (Equation 9) below.

[0061]

number

[0062] In this embodiment, the parameters of the operation generation unit 30 are adjusted so that the computation load Lcs of the control device 28 does not exceed the allowable computation load La, thereby reducing the computation load.

[0063] <Parameter adjustment unit 33> This section describes a specific method for adjusting the parameters that control the computational load in the parameter adjustment unit 33.

[0064] Figure 4 shows the relationship between parameters related to the computational load of the MPC in the motion generation unit. In Figure 4, the parameters related to the computational load [%] of the motion generation unit 30 are the number of predicted horizons [No.] and the calculation period [s] of the motion generation unit 30.

[0065] The number of predicted horizons [No.] is a parameter that adjusts the time width predicted by the MPC (predicted time width). The higher the number of predicted horizons [No.], the further into the future the toe position can be predicted. In other words, the higher the number of predicted horizons [No.], the longer the predicted time width becomes, and the greater the computational load [%] of the motion generation unit 30. The future predicted time width can be calculated by multiplying the number of predicted horizons [No.] by the calculation period [s] of the motion generation unit 30.

[0066] Ideally, the number of predicted horizons and the calculation period should be determined based on the predicted time width and control accuracy intended by the designer. However, the number of predicted horizons and the calculation period should be set to avoid task overruns that may occur when the computational load becomes large. Specifically, the parameter adjustment unit 33 reduces the number of predicted horizons or slows down (lengthens) the calculation period according to the computational load to prevent task overruns.

[0067] As shown in Figure 4, the parameter adjustment unit 33 pre-determines table data showing the relationship between computation load [%], predicted number of horizons [No.], and computation period [s], and outputs appropriate parameters to the motion generation unit 30 according to the computation load Lcs of the motion generation unit 30 based on this table data. Note that slowing down (lengthening) the computation period also affects the granularity of the motion command values ​​generated by the motion generation unit 30, so it is desirable to prioritize reducing the predicted number of horizons first, and then slowing down (lengthening) the computation period in the order of adjustment.

[0068] Next, we will explain specific ways to prevent task overruns.

[0069] Figure 5 shows the time variation of the allowable computational load, the computational load of the control device, and the actual allowable computational load.

[0070] For example, if parameter adjustments are not made as in this embodiment, a task overrun will occur when the computation load Lcs of the control device 28 exceeds the allowable computation load La. If a task overrun occurs, real-time control becomes difficult, and it may not be possible to achieve the expected control accuracy. One example of a case in which a task overrun may occur is when the communication load Lt temporarily increases due to a communication error with another system.

[0071] In contrast, in this embodiment, as shown in Figure 5, when the computation load Lcs of the control device 28 approaches the allowable computation load La (in this case, when it reaches the actual allowable computation load LaMargin), the parameter adjustment unit 33 changes the parameters of the operation generation unit 30 to reduce the computation load Lcs, thereby preventing task overruns from occurring by ensuring that the computation load Lcs does not exceed the allowable computation load La. When the allowable computation load La returns to its rated value, the parameters of the operation generation unit 30 are returned to the design value.

[0072] <Caution section 34> The warnings in the warning section 34 will be explained below.

[0073] The alerting unit 34 determines whether an alert is necessary based on the computational load of the control device 28 estimated by the computational load estimation unit 32, and if it determines that an alert is necessary, it notifies the operator of the alert. Specifically, first, when the computational load Lcs of the control device 28 reaches the actual allowable computational load LaMargin, it notifies the operator that the intended operation may not be possible. Next, if it is not possible to address the issue by adjusting the parameters of the operation generation unit 30 by the parameter adjustment unit 33, that is, if the computational load of the control device 28 cannot be sufficiently reduced, it notifies the operator again that the calculation of the operation generation unit 30 will be stopped.

[0074] Figure 6 is a flowchart showing the processing steps of the control device.

[0075] In Figure 6, the control device 28 first inputs work design information acquired from the user interface or another system and stored in the work design information storage device 29 (step S101), and then acquires attitude information of the upper rotating body 22 and the front work device 24 from attitude sensors 26A, 26B, 26C, and 26D (step S102).

[0076] Next, the motion generation unit 30 calculates the target operation of each hydraulic actuator 5, 6, and 7 based on the tip position of the bucket 10 of the front work device 24 and the work design information (step S103).

[0077] Next, the computation load estimation unit 32 measures the computation load of the overall control device 101 (step S104) and the computation load of the control device 28 (step S105).

[0078] Here, it is determined whether the computational load of the control device 28 measured in step S105 exceeds the actual allowable computational load (step S106). If the result of the determination in step S106 is NO, that is, if the computational load of the control device 28 does not exceed the actual allowable computational load, the target operation generated by the operation generation unit 30 is output to the actuator control unit 31 (step S107), and the process ends (return to START).

[0079] Furthermore, if the determination result in step S106 is YES, that is, if the computational load of the control device 28 exceeds the actual allowable computational load, a warning is notified to the operator via the display device 36 (step S107).

[0080] Next, the parameter adjustment unit 33 adjusts the parameters of the MPC of the motion generation unit 30 (step S109), and it is determined whether or not it is possible to reduce the computation load by adjusting the parameters (step S110).

[0081] If the result of the determination in step S110 is YES, that is, if the computational load can be reduced by adjusting the parameters of the operation generation unit 30, the process returns to step S106.

[0082] Furthermore, if the determination result in step S110 is NO, that is, if it is difficult to reduce the computation load by adjusting the parameters of the motion generation unit 30, a warning is issued to the operator again via the display device 36 (step S111), the calculation of the motion generation unit 30 is stopped, the previous value of the target motion is output to the actuator control unit 31 (step S112), and the process is terminated (return to START).

[0083] The effects of this embodiment, configured as described above, will now be explained.

[0084] In this embodiment, the system includes a lower traveling body 20, an upper rotating body 22 rotatably mounted relative to the lower traveling body 20, a multi-jointed front working device 24 mounted on the upper rotating body 22 and having a bucket 10 (working tool) at its tip, hydraulic actuators 5, 6, 7, 23 (actuators) that drive the lower traveling body 20, the upper rotating body 22, and the front working device 24 respectively, posture sensors 26A, 26B, 26C, 26D that detect posture information, which is information regarding the posture of the upper rotating body 22 and the front working device 24, and work and design by the front working device 24. A hydraulic excavator 100 (working machine) is equipped with a control device 28 (drive control device) that acquires predetermined work design information related to the information and controls hydraulic actuators 5, 6, 7, 23 based on the detection results of attitude sensors 26A, 26B, 26C, 26D so that the bucket 10 of the front work device 24 operates according to the work design information, and is further equipped with a controller load measuring device 45 (control load measuring device) that measures the load of the overall control device 101 that controls the overall operation of the hydraulic excavator 100 including the control device 28, and the control device 28 acquires predetermined work design information related to the information related to the hydraulic excavator 100, and controls hydraulic actuators 5, 6, 7, 23 based on the detection results of attitude sensors 26A, 26B, 26C, 26 Based on the detection results of C,26D and work design information, the system includes: an motion generation unit 30 that generates a target motion of the front work device 24 using parameters; an actuator control unit 31 that calculates the target operating speed of the hydraulic actuators 5,6,7 based on the target motion generated by the motion generation unit 30, and generates and outputs a control signal to control the operation of the hydraulic actuators 5,6,7 at the calculated target operating speed; a calculation load estimation unit 32 that calculates the calculation time of the target motion in the motion generation unit 30 and the calculation time of the target operating speed in the actuator control unit, and estimates the calculation load of the control device 28 based on the two calculated calculation times and the load of the overall control device 101 measured by the controller load measurement device 45; and a parameter adjustment unit 33 that adjusts the parameters to reduce the calculation load of the motion generation unit 30 if the calculation load estimated by the calculation load estimation unit 32 is determined to be higher than a predetermined reference value. By adjusting the parameters related to the calculation load within the control device according to the allowable calculation load and the calculation load of the control device, it is possible to prevent the calculation load in the control device from exceeding the allowable calculation load and suppress a decrease in control accuracy.

[0085] <Second Embodiment> A second embodiment of the present invention will be described with reference to Figures 7 to 10. In this embodiment, components similar to those in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted as appropriate.

[0086] In the first embodiment, the computational load Lcs of the control device 28 was prevented from exceeding the allowable computational load La by adjusting parameters related to the computational load Lcs of the control device 28 in accordance with the allowable computational load La of the overall control device 101 and the computational load Lcs of the control device 28. In this embodiment, in addition to the configuration of the first embodiment, the possibility of intrusion and deviation is calculated based on the positional relationship between a representative point of the hydraulic excavator 100 and the control surface 40, and if the computational load Lcs of the control device 28 is high and the possibility of intrusion and deviation is high, the control method is changed to one that has a lower possibility of intrusion and deviation.

[0087] Figure 7 is a schematic functional block diagram showing some of the processing functions of the control device installed in the hydraulic excavator according to this embodiment.

[0088] In Figure 7, the control device 28A includes an action generation unit 30, an actuator control unit 31, a computation load estimation unit 32A, a parameter adjustment unit 33A, a warning unit 34, an intrusion / deviation determination unit 38, and a switching unit 39.

[0089] As shown in Figure 7, the control device 28A receives operation commands corresponding to the amount of movement of the operation levers 2a and 2b by the operator.

[0090] The motion generation unit 30A generates target movements (motion commands) for each hydraulic actuator 5, 6, 7, 23, such as target cylinder speed and target rotational speed, using parameters based on operation commands from the operation levers 2a and 2b, posture information detected by the posture sensor 26, and work design information pre-stored in the work design information storage device 29, and transmits them to the actuator control unit 31. The parameters of the motion generation unit 30 can be adjusted by the parameter adjustment unit 33.

[0091] The intrusion / deviation determination unit 38 calculates the toe position of the bucket 10 as the representative coordinate of the front work device 24 based on the detection results of the attitude sensors 26A, 26B, 26C, and 26D, and calculates the distance between the representative coordinate (toe position) and the control surface 40 (described later), which is set in advance as work design information. The intrusion / deviation determination unit 38 then performs an intrusion / deviation determination process to determine whether the representative coordinate of the bucket 10 enters or deviates from the control surface 40 in the predicted operation based on the operation commands from the operation levers 2a and 2b, and in the target operation for a predetermined number of predicted horizons of the front work device 24 calculated by the motion generation unit 30. The intrusion / deviation determination unit 38 outputs the determination result of the intrusion / deviation determination process to the parameter adjustment unit 33 and the calculation load estimation unit 32A.

[0092] The computation load estimation unit 32A estimates the computation load of the control device 28 based on information related to the load of the overall control device 101A obtained from the controller load measurement device 45 (for example, power consumption) and the computation load of the motion generation unit 30 and the actuator control unit 31. It then determines whether the estimation result is higher than a predetermined reference value and transmits the determination result to the parameter adjustment unit 33 and the warning unit 34.

[0093] The switching unit 39 switches the target operation output to the actuator control unit 31 to either the target operation of the front work device 24 calculated by the operation generation unit 30A or the operation commands from the operation levers 2a and 2b, according to the parameters from the parameter adjustment unit 33A.

[0094] The parameter adjustment unit 33A adjusts the parameters to reduce the computation load of the motion generation unit 30A based on the computation load estimation result of the control device 28 estimated by the computation load estimation unit 32A. The parameter adjustment unit 33A also adjusts the parameters of the switching unit 39 based on the determination result of the intrusion / deviation determination process in the intrusion / deviation determination unit 38. Specifically, if the intrusion / deviation determination unit 38 determines that there is no possibility of intrusion or deviation, the parameters of the switching unit 39 are adjusted so that the target operation of the front work device 24 calculated by the motion generation unit 30A is selected and input to the actuator control unit 31. If the intrusion / deviation determination unit 38 determines that there is a possibility of intrusion or deviation, the parameters of the switching unit 39 are adjusted so that the operation commands from the operation levers 2a and 2b are selected as target operations and input to the actuator control unit 31.

[0095] Figures 8 and 9 are schematic diagrams illustrating the contents of the intrusion / deviation detection process.

[0096] Figure 8 shows how the hydraulic excavator 100 determines whether it will enter the control surface 40, which is set vertically in the xz plane. Starting from the current tip position t00a of the bucket 10 of the hydraulic excavator 100, the tip position for multiple calculation cycles is determined based on multiple motion commands. For example, in the case of trajectories t11a to t14a, it can be seen that the tip (representative point) of the bucket 10 generates an action that causes it to enter the control surface 40. On the other hand, in the case of trajectories t21a to t24a, it can be seen that the tip (representative point) of the bucket 10 avoids entering the control surface 40.

[0097] If intrusion avoidance is determined in the target operation generated by the motion generation unit 30A, the parameter adjustment unit 33A selects the target operation from the motion generation unit 30A and sends the parameters to the switching unit 39 to output to the actuator control unit 31. At this time, the toes of the bucket 10 perform an operation following the trajectory t11a to t14a.

[0098] Furthermore, if intrusion is detected in the target operation generated by the motion generation unit 30A, the parameter adjustment unit 33A selects the operation commands from the operation levers 2a and 2b as the target operation and transmits the parameters to the switching unit 39 to be output to the actuator control unit 31.

[0099] Furthermore, if intrusion into the control surface 40 is expected in either the target operation from the motion generation unit 30A or the operation commands from the operation levers 2a and 2b, the parameter adjustment unit 33A transmits a parameter to the switching unit 39 to stop the output of the target operation to the actuator control unit 31, thereby stopping the operation of the hydraulic actuators 5, 6, and 7. In addition, if there is a change in the operation mode selected by the operator (such as the output of the MPC), it is desirable to notify the operator via the warning unit 34.

[0100] Figure 9 shows how the hydraulic excavator 100 determines whether it will enter the control surface 41, which is set horizontally in the xz plane. Starting from the current tip position t00b of the bucket 10 of the hydraulic excavator 100, the tip position for multiple calculation cycles is determined based on multiple motion commands. For example, in the case of trajectories t11b to t14b, it can be seen that the tip (representative point) of the bucket 10 generates an action that causes it to enter the control surface 41. On the other hand, in the case of trajectories t21b to t24b, it can be seen that the tip (representative point) of the bucket 10 avoids entering the control surface 41.

[0101] If intrusion avoidance is determined in the target operation generated by the motion generation unit 30A, the parameter adjustment unit 33A selects the target operation from the motion generation unit 30A and sends the parameters to the switching unit 39 to output to the actuator control unit 31. At this time, the toes of the bucket 10 perform an operation following the trajectory t11b to t14b.

[0102] Furthermore, if intrusion is detected in the target operation generated by the motion generation unit 30A, the parameter adjustment unit 33A selects the operation commands from the operation levers 2a and 2b as the target operation and transmits the parameters to the switching unit 39 to be output to the actuator control unit 31.

[0103] Furthermore, if intrusion into the control surface 40 is expected in either the target operation from the motion generation unit 30A or the operation commands from the operation levers 2a and 2b, the parameter adjustment unit 33A transmits a parameter to the switching unit 39 to stop the output of the target operation to the actuator control unit 31, thereby stopping the operation of the hydraulic actuators 5, 6, and 7. In addition, if there is a change in the operation mode selected by the operator (such as the output of the MPC), it is desirable to notify the operator via the warning unit 34.

[0104] Figure 10 is a flowchart showing the processing contents of the control device according to this embodiment.

[0105] In Figure 10, the control device 28A first inputs work design information acquired from the user interface or another system and stored in the work design information storage device 29 (step S201), and then acquires attitude information of the upper rotating body 22 and the front work device 24 from attitude sensors 26A, 26B, 26C, and 26D (step S202).

[0106] Next, the motion generation unit 30A calculates the target operation of each hydraulic actuator 5, 6, and 7 based on the tip position of the bucket 10 of the front work device 24 and the work design information (step S203).

[0107] Next, the computation load estimation unit 32A measures the computation load of the overall control device 101A (step S204) and the computation load of the control device 28A (step S205).

[0108] Here, it is determined whether the computational load of the control device 28A measured in step S205 exceeds the actual allowable computational load (step S206). If the result of the determination in step S206 is NO, that is, if the computational load of the control device 28A does not exceed the actual allowable computational load, the target operation generated by the operation generation unit 30A is output to the switching unit 39 (step S207).

[0109] Furthermore, if the determination result in step S206 is YES, that is, if the computational load of the control device 28A exceeds the actual allowable computational load, a warning is notified to the operator via the display device 36 (step S207).

[0110] Next, the parameter adjustment unit 33A adjusts the parameters of the MPC of the motion generation unit 30A (step S209), and it is determined whether or not it is possible to reduce the computation load by adjusting the parameters (step S210).

[0111] If the result of the determination in step S210 is YES, that is, if the computational load can be reduced by adjusting the parameters of the operation generation unit 30A, the process returns to step S206.

[0112] Furthermore, if the determination result in step S210 is NO, that is, if it is difficult to reduce the computation load by adjusting the parameters of the motion generation unit 30A, a warning is issued to the operator again via the display device 36 (step S211), the calculation of the motion generation unit 30A is stopped, and the previous value of the target operation is output to the switching unit 39 (step S212).

[0113] When the processing in step S207 or step S212 is completed, the future position of the representative point of the vehicle body is calculated for each input (step S213), and it is determined whether or not there is a possibility of the future representative point of the vehicle body entering or leaving the input (step S214).

[0114] If the result of the determination in step S214 is NO, that is, if there is no possibility of future intrusion or deviation of the vehicle body representative point, the switching unit 39 selects the target operation from the operation generation unit 30A (including the previous value of the MPC) and outputs it to the actuator control unit 31 (step S215), and the process ends (returns to START).

[0115] Furthermore, if the determination result in step S214 is YES, that is, if there is a possibility of future intrusion or deviation from the vehicle body representative point, a warning is again issued via the display device 36 (step S216), the switching unit 39 selects an output other than the MPC (in this case, an operation command from the operation levers 2a and 2b) as the target operation and outputs it to the actuator control unit 31 (step S217), and the process ends (returns to START).

[0116] The other configurations are the same as in the first embodiment.

[0117] In this embodiment configured as described above, the same effects as in the first embodiment can be obtained.

[0118] Furthermore, based on the positional relationship between the representative point of the hydraulic excavator 100 (the tip of the bucket 10) and the control surfaces 40 and 41, the possibility of the representative point entering or leaving the control surfaces 40 and 41 is calculated. If the possibility of entry or departure is high, the control method is changed to one with a lower probability of entry or departure, thereby suppressing a decrease in control accuracy. In particular, when the computational load Lcs of the control device 28 is high, the control method is changed to one with a lower probability of entry or departure, thereby improving work continuity while suppressing a decrease in control accuracy.

[0119] <Note> It should be noted that the present invention is not limited to the embodiments described above, and includes various modifications and combinations that do not depart from the spirit of the invention. Furthermore, the present invention is not limited to having all the configurations described in the embodiments described above, and includes configurations in which some of the configurations are omitted. In addition, some or all of the above configurations, functions, etc. may be realized by designing, for example, an integrated circuit. Furthermore, each of the above configurations, functions, etc. may be realized in software by having a processor interpret and execute a program that realizes each function. [Explanation of Symbols]

[0120] 2...Cab, 2a,2b...Operating levers (operating devices), 3a,3b...Travel motors, 5...Boom cylinder, 6...Arm cylinder, 7...Bucket cylinder, 8...Boom, 9...Arm, 10...Bucket, 20...Lower travel body, 21...Slewing mechanism, 22...Upper slewing body, 23...Slewing motor, 24...Front working device, 25...Slewing central axis, 26,26A,26B,26C,26D...Attitude sensors, 28,28A...Control device 100...Hydraulic excavator (working machine), 101, 101A...Overall control unit

Claims

1. Lower running body and An upper slewing body is provided so as to be rotatable relative to the lower traveling body, A multi-jointed front work device provided on the upper rotating body and having a work tool at its tip, Actuators that drive the lower traveling body, the upper rotating body, and the front working device, respectively, A posture sensor that detects posture information, which is information regarding the posture of the upper rotating body and the front work device, A drive control device acquires predetermined work design information related to the work and design performed by the front work device, and controls the actuator based on the detection result of the attitude sensor so that the work tools of the front work device operate according to the work design information. In the work machine, The system includes a control load measuring device that measures the load on the overall control device that controls the overall operation of the work machine, including the drive control device, The drive control device is A motion generation unit generates a target motion of the front work device using parameters based on the detection results of the attitude sensor and the work design information, An actuator control unit calculates the target operating speed of the actuator based on the target motion generated by the motion generation unit, and generates and outputs a control signal to control the operation of the actuator at the calculated target operating speed. A calculation load estimation unit calculates the calculation time for the target motion in the motion generation unit and the calculation time for the target motion speed in the actuator control unit, and estimates the calculation load of the drive control unit based on the two calculated calculation times and the load of the overall control unit measured by the control load measuring device, If the computation load estimated by the computation load estimation unit is determined to be higher than a predetermined reference value, the parameter adjustment unit adjusts the parameters to reduce the computation load of the operation generation unit. A work machine characterized by having the following features.

2. In the work machine described in claim 1, The parameter adjustment unit is A work machine characterized in that, if the calculation load of the drive control device estimated by the calculation load estimation unit is determined to be higher than the reference value, the number of predicted horizons and the calculation period of the motion generation unit included in the parameters are adjusted to reduce the calculation load of the motion generation unit.

3. In the work machine described in claim 2, The parameter adjustment unit is A work machine characterized by adjusting the parameters using a pre-set table data to determine the relationship between the predicted number of horizons and the calculation period related to the computational load of the motion generation unit.

4. In the work machine described in claim 3, The parameter adjustment unit adjusts the parameters so as to stop the calculation of the motion generation unit if, after the calculation load of the motion generation unit has been reduced by adjusting the parameters, the calculation load of the drive control device estimated by the calculation load estimation unit is higher than the reference value. The operation generation unit is characterized in that, when the parameters are adjusted by the parameter adjustment unit to stop the calculation, it outputs the target operation calculated in the previous calculation cycle to the actuator control unit.

5. In the work machine described in claim 4, The device further includes an operating device that outputs an operating command for operating the actuator according to the amount of operation performed by the operator, The drive control device is Based on the detection results of the attitude sensor, the system calculates the representative coordinates of the work tool of the front work device, calculates the distance between the control surface, which is set in advance as work design information, and the representative coordinates of the work tool, and determines whether the representative coordinates of the work tool enter the control surface in the predicted operation based on the operation command from the operating device and the target operation for a predetermined number of predicted horizons of the front work device calculated by the motion generation unit. The system includes a switching unit that, according to the parameters from the parameter adjustment unit, switches the target operation output to the actuator control unit to either the target operation of the front work device calculated by the operation generation unit or the operation command from the operation device, The parameter adjustment unit is characterized by outputting a parameter to switch the output of the switching unit based on the determination result of the intrusion / deviation determination unit.

6. In the work machine described in claim 1, It is equipped with a display unit that displays vehicle information and presents it to the operator. The drive control device is characterized in that, when the calculation load of the drive control device estimated by the calculation load estimation unit is determined to be higher than the reference value, the drive control device has a warning unit that notifies the operator via the display unit to alert them.

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