Work machine

Abstract

The controller of the operating machinery performs the following model predictive control: It sets constraints in the model predictive control to prevent the operating device from intruding into the intrusion prevention zone. The controller calculates the target motion speed of the hydraulic actuator for a predetermined period starting from the current time point, in a manner that satisfies the constraints and minimizes the deviation between the coordinates of the operating tool and its target coordinates. Based on the posture of the operating device detected by the posture detection device, the controller calculates the motion speed of the hydraulic actuator and controls it to match the target motion speed. It determines whether the position of the control point of the operating device has deviated from the constraints. If it determines that the position of the control point of the operating device has deviated from the constraints, it executes motion prohibition control to prohibit or stop the operation of the operating device.

Description

Technical Field

[0001] This invention relates to a work machine with a multi-joint type working device. Background Technology

[0002] In response to the need for information-based construction, hydraulic excavators (operating machinery) have been developed that feature machine guidance that displays the position and posture of the multi-jointed working device, including the bucket (working tool), to the operator, and mechanical control (driver support control) that controls the movement of the working device along the target excavation face.

[0003] Patent Document 1 discloses a control system that uses Model Predictive Control (MPC) to control the working device, causing the bucket of a hydraulic excavator to move along the target digging face. Model Predictive Control is a control method that calculates the control input by minimizing the value of an evaluation function up to a predetermined time target. Model Predictive Control is suitable for controlling working machinery with multiple joints. Using Model Predictive Control eliminates the need to separately design the cylinder drive amounts for the boom and stick; appropriate cylinder drive amounts can be automatically calculated based on the situation. Furthermore, as an advantage of Model Predictive Control, it is widely known that it can explicitly handle constraints, meaning that calculations can be performed quickly with less computation. Patent Document 1 illustrates a method to avoid actions such as the bucket over-digging the target digging face by considering constraints related to the target digging face (design face) and the position of the bucket.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2020-125594 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] In the mechanical control of hydraulic excavators, GNSS (Global Navigation Satellite System) is used to calculate the excavator's position in three-dimensional space (vehicle position), and the coordinates of the bucket teeth are calculated based on the relationship between the target excavation surface and the vehicle's position. However, when using GNSS, the calculated vehicle position can vary significantly due to changes in the number of satellites available for positioning and interruptions in correction information. For example, it's possible that although the actual bucket teeth are located at the target excavation surface, the calculated coordinates of the teeth may be below the target excavation surface. Furthermore, when the operator manually sets the target excavation surface, it's also possible to set it at a position higher than the current bucket teeth. In this case, the calculated coordinates of the teeth will be below the target excavation surface.

[0009] If the calculated coordinates of the bucket tooth tip are below the target excavation surface, it is considered that constraint deviance has occurred in model predictive control. In the event of constraint deviance, the bucket may perform abrupt movements in order to recover from the constraint deviance as early as possible. Furthermore, when optimizing using a state that does not meet the constraints as the initial state, unexpected behaviors may occur during repeated optimization calculations. That is, if constraint deviance occurs, the operation of the machinery may become unstable.

[0010] The purpose of this invention is to prevent unstable operation of the working machinery when the constraints are broken.

[0011] Solution for solving the problem

[0012] One aspect of the present invention provides a working machine comprising: a working device having a plurality of driven components including a working tool and a plurality of hydraulic actuators for driving the plurality of driven components; a body on which the working device is mounted; a posture detection device for detecting the posture of the working device; a position detection device for detecting the position of the body; and a controller for controlling the movement of the working device. The controller performs model predictive control as follows: based on the posture of the working device detected by the posture detection device and the position of the body detected by the position detection device, it calculates the coordinates of the working tool at the current time point; based on the coordinates of the working tool and the boundary between a motion-limiting area allowing the movement of the working device and an intrusion-prevention area preventing the intrusion of the working device, it sets constraints in the model predictive control to prevent the working device from intruding into the intrusion-prevention area; and calculates a target movement speed of the hydraulic actuators for a predetermined time period from the current time point in such a way that the deviation between the coordinates of the working tool and the target coordinates of the working tool is reduced. The controller performs the following actions to prohibit control: based on the posture of the working device detected by the posture detection device, it calculates the action speed of the hydraulic actuator, controls the hydraulic actuator in a manner that the action speed of the hydraulic actuator is consistent with the target action speed, determines whether the position of the control point of the working device has deviated from the constraint conditions, and prohibits or stops the operation of the working device if the boundary surface is set in a manner that the coordinates of the working tool are located in the intrusion prevention area, or if the position of the control point of the working device is determined to have deviated from the constraint conditions due to the deterioration of the detection accuracy of the position detection device.

[0013] Invention Effects

[0014] According to the present invention, unstable operation of the working machinery can be prevented in the event of loss of constraint. Attached Figure Description

[0015] Figure 1 This is an exterior view of a hydraulic excavator.

[0016] Figure 2 It is a block diagram that shows the hardware structure and functions of the controller.

[0017] Figure 3 This is a block diagram illustrating the detailed functions of the controller according to the first embodiment.

[0018] Figure 4A This is a diagram representing an example of a target surface, specifically an example where the target surface is a horizontal plane.

[0019] Figure 4BThis is a diagram representing an example of a target surface, specifically an example where the target surface is an inclined plane.

[0020] Figure 4C This is a diagram representing an example of a target surface, indicating an example where multiple target surfaces are defined.

[0021] Figure 5 This is a flowchart illustrating an example of the processing sequence of the controller in the first embodiment.

[0022] Figure 6A This is a diagram showing a hydraulic excavator operating within a defined area of ​​motion.

[0023] Figure 6B It is a diagram showing the state of a part of the working device intruding into the intrusion prevention zone.

[0024] Figure 7 This is a block diagram showing the detailed functions of the controller in the second embodiment.

[0025] Figure 8 This is an example of an attention-grabbing screen displayed on the screen of a user interface (touch panel monitor).

[0026] Figure 9A This diagram illustrates the state where the bucket has disengaged from the actual movement limit area.

[0027] Figure 9B This diagram illustrates the alternative constraints set to make the bucket move closer to the actual motion limit area.

[0028] Figure 10A This is a flowchart illustrating an example of the processing sequence of the controller in the second embodiment.

[0029] Figure 10B This is a flowchart illustrating an example of the processing sequence of the controller in a variant of the second embodiment.

[0030] Figure 11 This is a block diagram showing the detailed functions of the controller in the third embodiment.

[0031] Figure 12 This is a block diagram showing the detailed functions of the controller in the fourth embodiment. Detailed Implementation

[0032] <First Implementation Method>

[0033] The embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 This is an exterior view of hydraulic excavator 1. (For example...) Figure 1As shown, the hydraulic excavator 1, as a working machine, includes: a working device 41 for performing excavation operations, etc.; and a body 42 on which the working device 41 is rotatably mounted. The body 42 includes a self-propelled traveling body 2 and a rotating body 3 rotatably mounted on the traveling body 2. The rotating body 3 is configured, for example, to rotate relative to the traveling body 2 via a rotary hydraulic motor 4, which is a hydraulic actuator.

[0034] The working device 41 is a multi-joint type working device. The working device 41 includes: multiple driven components; and multiple hydraulic actuators that drive the multiple driven components. The multiple driven components are rotatably connected in a vertical plane. The multiple driven components are the boom 6, the stick 7, and the bucket 8, which serves as the working tool. The base end of the boom 6 is rotatably mounted to the front of the slewing body 3 via a boom pin 6a. The front end of the stick 7 is rotatably mounted to the front end of the boom 6 via a stick pin 7a. The bucket 8 is rotatably mounted to the front end of the stick 7 via a bucket pin 8a. The multiple hydraulic actuators (hydraulic cylinders) constituting the working device 41 are the boom cylinder 10 that drives the boom 6, the stick cylinder 11 that drives the stick 7, and the bucket cylinder 12 that drives the bucket 8. Furthermore, the bucket cylinder 12 drives the bucket 8 via a connecting rod member 13 that rotates in conjunction with the bucket 8.

[0035] The vehicle body 2 is equipped with tracked driving devices 14 on the left and right sides. The driving devices 14 drive the vehicle body 2 by driving a driving hydraulic motor 14a, which is a hydraulic actuator.

[0036] The slewing unit 3 includes: a driver's cab 16 for the operator to ride in; and a machinery room 17 for housing various equipment. The driver's cab 16 is equipped with electrical operating devices 18a, 18b, and 18c for operating the hydraulic actuators (4, 10, 11, 12, 14a). Operating devices 18a and 18b, for example, have operating levers capable of tilting forward, backward, left, and right. Operating devices 18a and 18b have operating sensors (not shown) that electrically detect the tilting direction and amount of the operating levers, i.e., the operating direction and amount. The operating sensors output operating signals corresponding to the detected operating direction and amount to the controller 100.

[0037] The forward and backward movement and the left and right movement of the operating devices 18a and 18b are respectively assigned to the operation of each hydraulic actuator (4, 10, 11, 12). That is, each operation of the operating devices 18a and 18b is assigned to the operation of the working device 41 (drive indication of hydraulic actuators (10, 11, 12)) and the rotation operation of the rotating body 3 (drive indication of hydraulic actuator (4)). The operating device 18c has a travel lever that can tilt forward and backward and a travel pedal. The operating device 18c is assigned to the travel operation of the left and right travel device 14, that is, the drive indication of the hydraulic actuator (14a).

[0038] A user interface 19 is provided in the driver's cab 16. The user interface 19 includes a display device 19b for displaying various information (see reference). Figure 3 ) and the input device 19a that outputs input signals corresponding to the operator's operation to the controller 100 (see reference ) Figure 3 The display device 19b is a monitor with an LCD or similar device, which notifies the operator of information. The input device 19a is a touch sensor installed on the screen of the monitor, which is operated by the operator. That is, the user interface 19 in this embodiment is a touch panel monitor. In addition, the user interface 19 can be a structure installed in the cab 16, or it can be configured as a movable tablet terminal that can be installed and removed from the cab 16.

[0039] The machine room 17 houses a prime mover 21, including an engine and an electric motor, as well as a hydraulic pump unit 22 driven by the prime mover 21. The hydraulic pump unit 22, driven by the prime mover 21, draws in working oil from the oil tank and discharges it through the discharge pipe. The hydraulic oil ejected from the hydraulic pump unit 22 is supplied to various hydraulic actuators (4, 10, 11, 12, 14a). This drives each hydraulic actuator (4, 10, 11, 12, 14a). The driving of each hydraulic actuator (4, 10, 11, 12, 14a) is controlled by a control valve unit 23, which is an assembly of control valves corresponding to each hydraulic actuator (4, 10, 11, 12, 14a). Each control valve constituting the control valve unit 23 controls the direction and flow rate of the hydraulic oil (working oil) supplied from the hydraulic pump unit 22 to the corresponding hydraulic actuator (4, 10, 11, 12, 14a). The actuation of each control valve is controlled, for example, by a pilot pressure (drive signal) output from a pilot pump (not shown) via a solenoid proportional valve (not shown). The controller 100 controls each solenoid proportional valve based on the operating signals from the operating devices 18a, 18b, and 18c. Thus, the actuation of each hydraulic actuator (4, 10, 11, 12, 14a) is controlled by the control valve unit 23.

[0040] like Figure 1 as well as Figure 2As shown, an inertial measurement unit (IMU) 25 is provided on the rotating body 3 to measure information related to the posture of the machine body 42 (rotating body 3). Additionally, inertial measurement units 26, 27, and 28 are also provided on the boom 6, stick 7, and bucket 8, which are components of the working device 41, respectively, to measure information related to the posture of each component (6, 7, 8). To distinguish these four inertial measurement units 25, 26, 27, and 28, the inertial measurement unit 25 for the rotating body 3 (machine body) is sometimes referred to as the machine body IMU, the inertial measurement unit 26 for the boom 6 as the boom IMU, the inertial measurement unit 27 for the stick 7 as the stick IMU, and the inertial measurement unit 28 for the bucket 8 as the bucket IMU. Furthermore, the bucket IMU 28 is usually provided on the linkage member 13 that rotates in conjunction with the bucket 8, but it can also be provided on any member that drives the bucket 8 in conjunction with it.

[0041] Each inertial measurement unit 25, 26, 27, and 28 is equipped with an angular velocity sensor for measuring the angular velocity of the measurement setup (the object being measured) and an accelerometer for measuring the acceleration. Each inertial measurement unit 25, 26, 27, and 28 includes an angle calculation device that uses the angular velocity measured by the angular velocity sensor and the acceleration measured by the accelerometer to calculate the angle of the object being measured.

[0042] For example, when the rotating body 3 is stationary, the IMU 25 can calculate the tilt (pitch angle) of the rotating body 3 relative to the horizontal plane (reference plane) in the forward-backward direction and the tilt (roll angle) in the left-right direction (width direction) based on the direction of gravitational acceleration measured in the IMU coordinate system set in the IMU 25 and the mounting state of the IMU 25 (the relative positional relationship between the IMU 25 and the rotating body 3). The IMU 25 outputs the calculated results of the pitch angle and roll angle of the rotating body 3 (attitude information of the rotating body 3) to the controller 100. In addition, the IMU 25 can calculate the rotation angle (yaw angle) of the rotating body 3 by integrating the detected angular velocity.

[0043] The boom IMU 26, stick IMU 27, and bucket IMU 28 respectively measure the angular velocity and acceleration of the measurement object (boom 6, stick 7, bucket 8), and calculate the angle of the measurement object relative to a reference based on the measurement results (acceleration and angular velocity). Specifically, each inertial measurement device 26-28 can calculate the rotation angle of the components (6, 7, 8) of the working device 41 by detecting the direction of gravity and integrating the detected angular velocity. The boom IMU 26, stick IMU 27, and bucket IMU 28 respectively output the measurement results of the angular velocity and acceleration of each component (6, 7, 8) and the calculated results of the angle information of each component (6, 7, 8) (the posture information of each component 6, 7, 8) to the controller 100.

[0044] The body IMU25, boom IMU26, stick IMU27, and bucket IMU28 constitute a posture detection device 29 that detects information related to the posture of the body 42 and the working device 41 (see reference). Figure 3 Furthermore, the angle calculation devices of each inertial measurement unit 25, 26, 27, and 28 can also be configured as a single calculation device. Additionally, the functions of the angle calculation devices of each inertial measurement unit 25, 26, 27, and 28 can also be provided by the controller 100. In this case, the angle calculation devices of the inertial measurement units can be omitted.

[0045] In this embodiment, by using the measurement results from the body IMU 25, boom IMU 26, stick IMU 27, and bucket IMU 28, the state quantities (angle, angular velocity, angular acceleration) of the swing hydraulic motor 4 and the state quantities (displacement, velocity, acceleration) of the boom cylinder 10, stick cylinder 11, and bucket cylinder 12 can be calculated. That is, each inertial measurement unit 25, 26, 27, and 28 functions as a state quantity detection device to detect information related to the state quantities of the hydraulic actuators (4, 10, 11, 12). Therefore, it is not necessary to prepare additional sensors to detect the state quantities of the hydraulic actuators (4, 10, 11, 12). However, the hydraulic excavator 1 may also include actuator sensors to detect the state quantities of the hydraulic actuators (4, 10, 11, 12). For example, a cylinder stroke sensor capable of detecting the stroke of a hydraulic cylinder can be used as an actuator sensor.

[0046] Two GNSS antennas 36 and 37 are installed on the rotating body 3 as receiving devices capable of receiving positioning signals from multiple GNSS satellites. The positioning signals received by each GNSS antenna 36 and 37 are input to the GNSS receiver 38 (see reference). Figure 2The GNSS receiver 38 performs positioning calculations based on the positioning signals received by the GNSS antennas 36 and 37, including calculations of the coordinates representing the positions of the GNSS antennas 36 and 37, and calculations of the azimuth angle of the rotating body 3 (the fuselage). The GNSS receiver 38 connects wirelessly to a fixed GNSS station located in the field, thereby enabling RTK (Real-Time Kinematic) positioning. In the absence of a fixed GNSS station, network-type RTK positioning utilizing information obtained from electronic base stations via the Internet can be performed. Hereinafter, it is assumed that the GNSS receiver 38 can perform RTK positioning regardless of the presence or absence of a fixed station in the field.

[0047] The GNSS receiver 38 can provide positioning status (standalone positioning, RTK-float, RTK-fix, etc.) to the controller 100. The controller 100 can estimate positioning accuracy (position detection accuracy) based on the positioning status provided by the GNSS receiver 38. Furthermore, statistical operations such as Kalman filtering are incorporated into the GNSS positioning calculation. Therefore, the GNSS receiver 38 can provide the correctness of the positioning result as error variance to the controller 100. Based on the error variance information provided by the GNSS receiver 38, the controller 100 can more accurately grasp the positioning accuracy information.

[0048] The GNSS receiver 38 outputs the positions (i.e., the position of the rotating body 3) of the GNSS antennas 36 and 37, as well as their speed and the azimuth angle of the rotating body 3 (the excavator body), which are the results of the positioning calculation, to the controller 100. The GNSS antennas 36 and 37 and the GNSS receiver 38 constitute a position detection device 35 for detecting the position of the body 42 (rotating body 3) of the hydraulic excavator 1 (see reference). Figure 3 ).

[0049] Figure 2 This is a block diagram that outlines the hardware structure and functions of the controller 100. For example... Figure 2 As shown, the controller 100 is composed of a computer having a processing unit 61, a storage unit 62, input / output interfaces, and other peripheral circuits. This hardware works together to enable software operation, realizing multiple functions. Furthermore, the controller can be composed of a single computer or multiple computers. The processing unit 61 consists of a CPU (Central Processing Unit), an MPU (Micro Processing Unit), a DSP (Digital Signal Processor), etc. The storage unit 62 consists of non-volatile memory such as ROM (Read Only Memory), flash memory, and hard disk drive, as well as volatile memory called RAM (Random Access Memory).

[0050] The non-volatile memory stores programs capable of performing various operations. That is, the non-volatile memory is a storage medium capable of reading programs that implement the functions of this embodiment. The volatile memory is a storage medium that temporarily stores the operation results of the processing device 61 and signals input from the input / output interface. The processing device 61 is a device that expands the program stored in the non-volatile memory into the volatile memory and performs operations, performing predetermined operations on data retrieved from the input / output interface, the non-volatile memory, and the volatile memory according to the program.

[0051] The input section of the input / output interface converts signals input from various devices (inertial measurement units 25, 26, 27, 28, GNSS receiver 38, user interface 19, etc.) into data that can be processed by the processing unit 61. Furthermore, the output section of the input / output interface generates an output signal corresponding to the processing result in the processing unit 61 and outputs this signal to various devices (hydraulic pump unit 22, control valve unit 23, user interface 19, etc.).

[0052] The controller 100 controls the movement of the hydraulic excavator 1. The controller 100 functions as a positioning calculation unit 101, a target setting unit 102, a motion control unit 103, and a display control unit 104 by executing programs stored in the storage device 62. Furthermore, the functions of the target setting unit 102 and the display control unit 104 are sometimes combined and referred to as the machine guidance system. Additionally, the functions of the target setting unit 102 and the motion control unit 103 are sometimes combined and referred to as the mechanical control system.

[0053] The positioning calculation unit 101 calculates the position (coordinates) and orientation of the hydraulic excavator 1 and the posture of the working device 41 at the work site based on the calculation results of the GNSS receiver 38 (i.e., position information) and the measurement results of each inertial measurement device 25, 26, 27, and 28. The positioning calculation unit 101 outputs the calculation results to the target setting unit 102, the motion control unit 103, and the display control unit 104.

[0054] The target setting unit 102 calculates a target surface that defines the target shape of the construction object (excavation object) based on construction information such as 3D construction drawings pre-stored in the storage device 62, and the position and posture information of the hydraulic excavator 1 as the calculation result of the positioning calculation unit 101. The construction information pre-stored in the storage device 62 is, for example, information input by the construction manager through the user interface 19 (input device 19a) or an external construction management system (not shown) of the hydraulic excavator 1. In addition, the target setting unit 102 calculates the distance between the target surface and the control point of the working device 41 (e.g., the tip of the bucket 8). Furthermore, the target surface can also be set on the spot by the operator through the operation input of the user interface 19. For example, when the traveling body 2 is in contact with the horizontal surface, when the operator inputs "-0.5m" as the height using the user interface 19, the target setting unit 102 sets a plane with a depth of 50cm as the target surface. As a result, it is possible to easily excavate a trench with a constant depth. The target setting unit 102 outputs the calculation results of the target surface, etc., to the motion control unit 103 and the display control unit 104.

[0055] The display control unit 104 controls, for example, the user interface 19 (display device 19b) within the cab 16, causing the display screen of the display device 19b to display a predetermined image. Based on the target surface calculated by the target setting unit 102 and the position and posture information of the hydraulic excavator 1 calculated by the positioning calculation unit 101, the display control unit 104 calculates instructions for operator support and displays the calculation results on the display device 19b. For example, by displaying the posture of the working device 41, the front end position of the bucket 8 of the working device 41, and the angle of the bucket 8 relative to the target surface on the display device 19b, the display control unit 104 performs the function of a machine guidance system supporting operator operation.

[0056] The motion control unit 103 controls the movement of the hydraulic excavator (body 42 and working device 41) by controlling the hydraulic system 24, which includes a hydraulic pump unit 22, multiple hydraulic actuators (4, 10, 11, 12, 14a), and a control valve unit 23. Based on the target surface calculated by the target setting unit 102 and the position and posture information of the body 42 and working device 41 calculated by the positioning calculation unit 101, the motion control unit 103 calculates the motion target of the body 42 and working device 41 that satisfies predetermined conditions. The motion control unit 103 controls the hydraulic system 24 to achieve the motion target by moving the body 42 and working device 41.

[0057] For example, the motion control unit 103 performs the function of a mechanical control system that controls the movement of the bucket 8 along the target surface or restricts the movement by preventing the tips of the bucket 8 from approaching the target surface by a certain distance.

[0058] The positioning calculation unit 101 may also have the function of verifying the accuracy of the posture information in the calculation results. The positioning calculation unit 101 determines whether the positioning results of each inertial measurement device 25, 26, 27, and 28 have become abnormal, and outputs the abnormality judgment result to the display control unit 104 and the motion control unit 103. In addition, the positioning calculation unit 101 determines whether the accuracy of the angle information in the calculation results of the posture detection device 29 has decreased, and outputs the accuracy judgment result to the display control unit 104 and the motion control unit 103.

[0059] If the positioning results of the inertial measurement units 25, 26, 27, and 28 are abnormal, or if the accuracy of the angle information calculated by any of the four inertial measurement units 25, 26, 27, and 28 does not meet the preset accuracy requirements, the display control unit 104 will stop the guidance execution and display a guidance interruption warning on the display device 19b. In other words, if the positioning results are abnormal or the accuracy of the angle information deteriorates, a screen will be displayed on the display device 19b to draw the operator's attention.

[0060] If the positioning results of each inertial measurement device 25, 26, 27, 28 are abnormal, or if the accuracy of the angle information of the calculation result of any one of the four inertial measurement devices 25, 26, 27, 28 does not meet the preset accuracy requirement, the motion control unit 103 stops the mechanical control function.

[0061] Reference Figure 3 The functions of controller 100 are described in detail. Figure 3 This is a block diagram illustrating the detailed functions of controller 100. For example... Figure 3As shown, the positioning calculation unit 101 includes a state calculation unit 111 that uses detection signals from the posture detection device 29, detection signals from the position detection device 35, and geometric information of the hydraulic excavator 1 to calculate the position and speed of the hydraulic excavator 1. The target setting unit 102 includes a target data calculation unit 121 that calculates the target coordinates of the tips of the bucket 8 teeth, etc., and a constraint setting unit 122 that sets constraint conditions for model predictive control. The motion control unit 103 includes a disengagement judgment unit 131 that determines whether a constraint disengagement has occurred based on the positional relationship between the bucket 8 and the target surface; a predictive control unit 132 that performs predictive control using a predictive control model; an actuator control unit 133 that controls the motion of the hydraulic actuator based on the calculation results of the predictive control unit 132; and a calculation condition modification unit 134 that changes the calculation conditions in the event of constraint disengagement. The aforementioned display control unit 104 includes an attention-awakening unit 141 that causes the display device 19b to display an image for attracting the operator's attention.

[0062] The state calculation unit 111 calculates the three-dimensional coordinates of a predetermined position of the hydraulic excavator 1, including the coordinates of the bucket 8 representing the current position, based on the posture of the working device 41 detected by the posture detection device 29, the position of the machine body 42 detected by the position detection device 35, and the geometric information of the hydraulic excavator 1. The coordinates of the hydraulic excavator 1 as the calculation result are, for example, global coordinate system coordinates. Furthermore, the global coordinate system coordinates can be converted to field coordinate system coordinates or excavator reference coordinate system coordinates. The geometric information of the hydraulic excavator 1, such as the length from the boom pin 6a to the stick pin 7a (boom length), the length from the stick pin 7a to the bucket pin 8a (stick length), and the length from the bucket pin 8a to the tip of the bucket 8 (bucket length), is pre-stored in the storage device 62. The state calculation unit 111 performs geometric calculations of the hydraulic excavator 1, but does not include a characteristic calculation method; therefore, the description of this calculation method is omitted.

[0063] The state calculation unit 111 can simultaneously calculate the coordinates of multiple positions in the hydraulic excavator 1. As a predetermined position (predetermined part) of the hydraulic excavator 1, it can set any position of the hydraulic excavator 1, such as the tip and back of the bucket 8, any position of the boom 6 and stick 7, and any position of the slewing body 3.

[0064] The state calculation unit 111 calculates state quantities (such as the extension and retraction speed and acceleration of the hydraulic cylinders) representing the working state of the hydraulic actuators (10, 11, 12) based on the posture information of the working device 41 detected by the posture detection device 29. For example, the state calculation unit 111 performs geometric calculations using the angle information of the driven components from the posture detection device 29, thereby calculating the length of the hydraulic cylinders (10, 11, 12). The state calculation unit 111 calculates the operating speed (extension and retraction speed) of the hydraulic cylinders (10, 11, 12) by performing a time derivative on the length of the hydraulic cylinders (cylinder length). The cylinder length is expressed as a function including the angle information of the driven components (6, 7, 8). Therefore, the time derivative of the cylinder length includes the angular velocity (linkage angular velocity) of the driven components (6, 7, 8). The angular velocities detected by the inertial measurement devices 26, 27, 28 are equivalent to the linkage angular velocities, so only this value needs to be used. The state calculation unit 111 can also calculate the extension and retraction acceleration of the hydraulic cylinders (10, 11, 12) in the same way. To calculate the cylinder extension and retraction acceleration, the connecting rod angular acceleration is required. The connecting rod angular acceleration can be calculated by using an approximation of the time change of the angular velocity detected by inertial measurement devices 26, 27, and 28.

[0065] The target data calculation unit 121 sets the target surface St, i.e. the target excavation surface Se, as the excavation target based on the construction information stored in the storage device 62 and the position of the machine body 42 calculated by the state calculation unit 111. Furthermore, the target data calculation unit 121 calculates the time series data of the target coordinates from the current time point to the predetermined time target by moving the tip of the bucket 8 along the target excavation surface Se.

[0066] Figures 4A to 4C This is a diagram representing an example of the target surface St. Figure 4A This example represents a target surface St that is horizontal. Figure 4B This represents an example where the target surface St is an inclined plane. Figure 4C This represents an example where multiple target surfaces St are defined. Furthermore, as... Figure 4C As shown, when multiple target surfaces St1 and St2 are set, the target data calculation unit 121 calculates the shortest distance from the tip of the bucket 8 to each target surface St1 and St2 within the working range. Based on the calculation result, the target surface St with the shortest distance to the tip of the bucket 8, i.e., the target surface St closest to the front end of the bucket 8, is selected as the target digging surface Se. Furthermore, when there is only one target surface St, the target data calculation unit 121 sets that target surface St as the target digging surface Se.

[0067] like Figures 4A to 4CAs shown, the target excavation surface Se corresponds to the boundary between the action-limiting area A1, which allows the hydraulic excavator 1 to move, and the intrusion-prevention area A2, which prevents the hydraulic excavator 1 from intruding. The controller 100 activates the working device 41 to bring the tip of the bucket 8, located away from the target excavation surface Se, closer to it. Furthermore, the controller 100 activates the working device 41 to move the tip of the bucket 8 along the target excavation surface Se. During these actions, the working device 41 operates within the action-limiting area A1, preventing intrusion into the intrusion-prevention area A2. That is, it prevents excavation beyond the target excavation surface Se.

[0068] The target data calculation unit 121 calculates the target value of the bucket 8's tooth tip speed, namely the tooth tip target speed Vt, based on the set target digging surface Se, the coordinates representing the position of the bucket 8's tooth tip (hereinafter also referred to as tooth tip coordinates), which are the calculation results of the state calculation unit 111, and the operation amount and operation direction of the operating devices 18a and 18b. This calculation is used to provide driving assistance control that respects the operator's operation of the operating devices 18a and 18b and satisfies the predetermined conditions. For example, the target data calculation unit 121 calculates the bucket 8's tooth tip target speed Vt corresponding to the operation direction and operation amount of the operating devices 18a and 18b while satisfying the condition that the front end of the bucket 8 does not submerge to a position lower than the target digging surface Se. The calculation method of the tooth tip target speed Vt is well known, so its description is omitted.

[0069] The target data processing unit 121 calculates, for example, the time series data of the target value of the tooth tip coordinate ξ(k) of the bucket 8 at time k (the time of the calculation point) and the target tooth tip velocity Vt(k) at time k. This is the tooth tip target coordinate ξr. For example, if it is assumed that the tooth tip of the bucket 8 moves at a constant speed of the tooth tip target velocity Vt(k), the tooth tip target coordinate ξr(k+M) in prediction step M is obtained by adding the control period (interval of calculation steps) Δt multiplied by the tooth tip target velocity Vt(k) to the tooth tip target coordinate ξr(k+M-1) in the previous step M-1.

[0070] When the tooth tip target coordinate ξr of the calculation result reaches the target excavation surface Se, the target data calculation unit 121 sets the tooth tip target coordinate ξr after that time on the target excavation surface Se. In this way, the tooth tip target coordinate ξr from time k+1 to time k+N (N is the predetermined prediction step) is calculated.

[0071] Figure 3 The constraint setting unit 122 shown sets constraints based on the position of the target excavation surface Se set by the target data calculation unit 121. For example, as Figure 4AAs shown, when the target excavation surface Se is given by a horizontal plane, the constraint condition for preventing the tip of the bucket 8 (control point) from crossing the target excavation surface Se is expressed by the following equation (1a). Similarly, the constraint condition for preventing the predetermined position (control point) of the back of the bucket 8 from crossing the target excavation surface Se is expressed by the following equation (1b). Furthermore, the tip coordinate ξ, which represents the position of the tip of the bucket 8, and the back coordinate η, which represents the position of the back of the bucket 8, are determined by coordinates in an orthogonal coordinate system with the horizontal axis as the x-axis and the vertical axis as the z-axis. The x-coordinate of the tip coordinate ξ of the bucket 8 is denoted as x1, and the z-coordinate of the tip coordinate ξ of the bucket 8 is denoted as z1. In addition, the x-coordinate of the back coordinate η of the bucket 8 is denoted as x2, and the z-coordinate of the back coordinate η of the bucket 8 is denoted as z2.

[0072]

[0073] Here, ε is the allowable excavation depth. For general construction, the allowable excavation depth ε is set to approximately 2 cm. Furthermore, the allowable excavation depth ε can be set to any value using the user interface 19. h is the height (z-coordinate) of the target excavation surface Se.

[0074] like Figure 4B As shown, when the target digging surface Se is given by an inclined plane, the constraint condition for preventing the tip of the bucket 8 from crossing the target digging surface Se is expressed by the following equation (2a). Similarly, the constraint condition for preventing the back of the bucket 8 from crossing the target digging surface Se is expressed by the following equation (2b).

[0075]

[0076] Here, a is the slope of the straight line representing the orthogonal coordinate system of the target excavation surface Se, and b is the intercept.

[0077] In addition, such as Figure 4C As shown, when the target surface St is assigned by a combination of a horizontal plane and an inclined plane, the target surface St closest to the bucket 8 is selected as the target digging surface Se, as described above. Therefore, when the target digging surface Se is switched according to the movement of the bucket 8, the constraint conditions are also switched. In this way, the constraint setting unit 122 sets constraint conditions to prevent the working device 41 from entering the intrusion prevention area A2 based on the position of the bucket 8 (tooth tip coordinates and back surface coordinates) and the target surface St.

[0078] Figure 3 The motion control unit 103 shown performs model predictive control that can be easily applied to the motion control of the hydraulic excavator 1. The motion control unit 103 performs motion control of the working device 41 based on a control input that makes the predicted values ​​of the state variables (position or speed) of a predetermined part of the working device 41 obtained using the predictive model follow their target values.

[0079] The motion control unit 103 can be used to control the coordinates of any part of the working device 41 of the hydraulic excavator 1. For simplicity, the following explanation will focus on the case where the coordinates (tooth tip coordinates) ξ of the tip of the bucket 8 are set as the controlled object. The motion control unit 103 can simultaneously control the slewing body 3, the traveling body 2, the boom 6, the stick 7, and the bucket 8. For simplicity, the following explanation will focus on the case where only the hydraulic actuators (boom cylinder 10, stick cylinder 11, and bucket cylinder 12) of the working device 41 are controlled. The motion control unit 103 performs position tracking control to make the actual coordinates of the tip of the bucket 8 follow the target coordinates of the tip.

[0080] The departure determination unit 131 determines whether the tooth tip coordinate ξ and back coordinate η of the bucket 8, calculated by the state calculation unit 111, have departed from the constraint conditions set by the constraint condition setting unit 122. That is, the departure determination unit 131 determines whether a departure from the constraint conditions has occurred. The constraint conditions are expressed by inequalities as shown in equations (1a), (1b), (2a), and (2b). Therefore, the departure determination unit 131 can easily determine whether the state satisfies the constraint conditions or the state is free from the constraint conditions.

[0081] Under the model predictive control described later, constraint deviance is almost nonexistent during normal operation. However, as mentioned above, if the target plane St set by the operator is inappropriate—for example, if the target plane St is set such that the tip coordinate of the bucket 8 exceeds the target plane St—or if the calculation result of the vehicle's position is incorrect primarily due to variations in the GNSS positioning status (e.g., the tip coordinate of the bucket 8 exceeds the target plane St due to variations in the GNSS positioning status, or the state of exceeding the target plane St is detected due to the recovery of the GNSS positioning status), constraint deviance may sometimes occur during the calculation process. That is, the tip coordinate ξ or the back coordinate η of the bucket 8 may be in a position that does not meet the constraint conditions. Furthermore, when the calculation cycle of the model predictive control is slow, or when the dynamics of the hydraulic excavator 1 envisioned in the model predictive control differ from the actual dynamics of the hydraulic excavator 1, the possibility of constraint deviance needs to be considered.

[0082] The predictive control unit 132 calculates the target motion speed (speed command value) vref of each hydraulic actuator (10, 11, 12) based on the current time k (the time of the calculation point) of the bucket 8 tooth tip position (tooth tip coordinate) ξ(k) calculated by the state calculation unit 111, the time series data of the target position (tooth tip target coordinate) ξr of the bucket 8 tooth tip from time k+1 to time k+N calculated by the target data calculation unit 121, and the constraints set by the constraint setting unit 122. The calculation of the target motion speed is realized using model predictive control.

[0083] The predictive control unit 132 calculates the target movement speed vref (extension speed) relative to the boom cylinder 10, stick cylinder 11, and bucket cylinder 12 by making the tip coordinate ξ of the bucket 8 follow the time series data of the target tip coordinate ξr of the bucket 8, which is the result of the calculation by the target data calculation unit 121. Specifically, based on the deviation between the predicted value of the tip coordinate of the bucket 8 in a predetermined time interval obtained by using a predictive model that predicts the state quantity of the tip of the bucket 8, i.e., the tip coordinate, by using the speed of each hydraulic actuator (10, 11, 12) as a control input and the time series data of the target tip coordinate ξr of the bucket 8, the result of the calculation by the target data calculation unit 121, the target movement speed vref of each hydraulic actuator (10, 11, 12) is calculated.

[0084] The target motion speed vref is calculated considering the following: When the controller 100 controls the hydraulic actuators (10, 11, 12), the actual speed response v of each hydraulic actuator (10, 11, 12) follows the target motion speed vref with a certain delay. This relationship can be expressed, for example, by a transfer function with a second delay, such as Equation (3).

[0085]

[0086] In equation (3), s represents the Laplace transform, ζ represents the attenuation coefficient, and ω represents the natural angular frequency. The subscript i is the number corresponding to the hydraulic actuator, i=1 represents boom cylinder 10, i=2 represents stick cylinder 11, and i=3 represents bucket cylinder 12.

[0087] The transfer function shown in equation (3) can be transformed into the state-space representation of equation (4). In equation (4), l and a contained in the state vector x represent the actual displacement and extension acceleration response of the hydraulic cylinder, respectively. u is the target motion speed vref, which is used as the control input. The subscript i is the number corresponding to the hydraulic actuator (boom cylinder 10, stick cylinder 11, bucket cylinder 12), just like in equation (3).

[0088]

[0089] Regarding equation (4), if we summarize the state vector xi and control input ui related to all hydraulic actuators (i = 1, 2, 3), we can obtain equation (5).

[0090]

[0091] Equation (5) can be discretized, for example, as shown in equation (6a) below, by using the control period Δt. Furthermore, since equation (5) is a linear system, it can also be accurately discretized using equation (6b) below.

[0092]

[0093] If the target operating speed vref of each hydraulic cylinder (10, 11, 12) as the control input u can be determined, then the state vector x up to the predetermined time target can be predicted by using equation (6a) or equation (6b). The state vector x includes the extension length (displacement) l of each hydraulic cylinder (10, 11, 12). Therefore, by specifying the extension length l of each hydraulic cylinder (10, 11, 12) of the driving device 41... i The angle θ between the driven components (6, 7, 8) constituting the working device 41 and the angle θ between the driven components (6, 7, 8) constituting the working device 41 i The function h1, which represents the geometric relationship between the components, can calculate the angle θ of each driven component (6, 7, 8). i That is, angle θ i It can be calculated according to the following formula (7).

[0094]

[0095] Angle θ1 is the tilt angle of boom 6 relative to the x-axis (boom angle), angle θ2 is the tilt angle of stick 7 relative to boom 6 (stick angle), and angle θ3 is the tilt angle of bucket 8 relative to stick 7 (bucket angle).

[0096] Furthermore, by using the angle θ of each component (6, 7, 8) of the specified working device 41... i The function h2, which relates the geometric relationship between the tip position of the bucket 8 and the tip position, can be used to calculate the tip coordinate ξ of the bucket 8. That is, the tip coordinate ξ can be calculated according to the following equation (8).

[0097]

[0098] Furthermore, equations (7) and (8) are purely geometric calculations without any special design, so the details of the equations are omitted. By using the series of equations (3) to (8) mentioned above, the time series data of the control input u from the time k of the calculation time point to the predetermined time target k+N, i.e., the time series data of the target action speed vref of each hydraulic cylinder (10, 11, 12), can be determined. Thus, the trajectory of the tooth tip coordinate ξ of the bucket 8 during this time interval (time series data of the coordinates) can be predicted.

[0099] The predictive control unit 132 calculates the predicted trajectory of the tooth tip coordinate ξ of the bucket 8 using the aforementioned predictive model that uses the speed of each hydraulic actuator (10, 11, 12) as the control input u. The predictive control unit 132 calculates the time series data (trajectory) of the control input u that makes the calculated predicted trajectory of the tooth tip coordinate ξ close to the target tooth tip coordinate ξr of the bucket 8. The predicted trajectory of the tooth tip coordinate ξ close to the trajectory of the target tooth tip coordinate ξr is equivalent to minimizing these deviations e(k) within a predetermined time interval (e(k) = ξ(k) - ξr(k)).

[0100] Furthermore, the smaller the control input u(k) that reduces the deviation e(k), i.e. the smaller the target motion speed vref, the smaller the motion of each hydraulic cylinder (10, 11, 12). Therefore, it is believed that the smaller the control input u(k), the more efficiently the hydraulic excavator 1 can be controlled.

[0101] These requirements are equivalent to minimizing the value of the evaluation function J assigned by equation (9). In equation (9), S, Q, and R are weight matrices, respectively. The control input u is preferably calculated in a manner that minimizes the evaluation function J. However, by adjusting the parameters S, Q, and R, it is possible to choose whether to prioritize eliminating the deviation e(k) or to prioritize reducing the control input u (target motion speed vref).

[0102]

[0103] Furthermore, the evaluation function J in equation (9) is an example. If we follow the above idea, we can also use different evaluation functions to calculate the control input u(k).

[0104] However, since the hydraulic actuator of the driving device 41 is a hydraulic cylinder (10, 11, 12), there is a limitation on the range of extension and retraction. Similarly, there are also limitations on the extension and retraction speed and acceleration of the hydraulic cylinders (10, 11, 12). These conditions can be expressed by the following equation (10).

[0105]

[0106] In equation (10), the subscript min represents the minimum value and the subscript max represents the maximum value. For the boom cylinder 10, stick cylinder 11, and bucket cylinder 12, the minimum and maximum values ​​are set to different or the same values ​​according to the specifications. Furthermore, the constraint condition of equation (10) is inherent to the hydraulic excavator that is being controlled and does not depend on construction information. That is, the constraint condition is not set by the constraint condition setting unit 122 and will not become the object of the departure judgment of the departure judgment unit 131. Originally, the constraint condition of equation (10) is a physical constraint condition, so during the operation of the hydraulic excavator 1, there will be no situation of departure from the constraint condition.

[0107] The constraints determined by the constraint setting unit 122 (equations (1a), (1b), (2a), (2b)) can be expressed as a more general expression (11) by using the function c.

[0108]

[0109] With the above preparations in place, model predictive control (MMCC) calculations are performed. Specifically, the MCC calculation involves solving the optimization problem of equation (12) with constraints, and calculating the optimal control input u. * Time series data U * Furthermore, in equation (12), "st" is an abbreviation for "subject to," meaning that subsequent mathematical expressions are used as constraints. In model predictive control, only the control input U of the time series (times k, k+1, ..., k+N) is used. * The control input (first input) u at time k in the middle * (k) is used as the actual target motion speed.

[0110]

[0111] The optimization problem in Equation (12) means that the control input u, which calculates the control input u that satisfies the constraints and is predicted using the prediction model, follows the target coordinate ξr of the bucket 8's tooth tip calculated based on the operation of the operating devices 18a and 18b, is the target coordinate ξr of the bucket 8's tooth tip. This means that the optimal target operating speed of the hydraulic actuators (10, 11, 12) for a predetermined period of time from the current time point is automatically calculated in a way that minimizes the deviation between the predicted value of the tooth tip coordinate ξ and the target coordinate ξr. Therefore, even if the number of hydraulic actuators for the controlled objects, such as the slewing body 3 and the hydraulic motor that tilts the rotor and rotates the bucket, is increased, it is possible to calculate the target operating speed that optimizes the overall operation of the hydraulic excavator 1 without calculating the target operating speed relative to each hydraulic actuator individually.

[0112] In this way, the predictive control unit 132 calculates the target movement speeds of the boom cylinder 10, stick cylinder 11, and bucket cylinder 12 in order to control the tooth tip coordinate ξ of the bucket 8. The calculation results of the predictive control unit 132 are output to the actuator control unit 133.

[0113] The actuator control unit 133 adjusts the operating speed (actual speed) of the hydraulic actuators (10, 11, 12) calculated by the state calculation unit 111 against the target operating speed vref (equivalent to u) calculated by the prediction control unit 132. * Feedback control of the hydraulic actuators (10, 11, 12) is performed in a consistent manner (k). Specifically, the actuator control unit 133 calculates the command value of the control valve unit 23 to achieve the target operating speed vref based on the deviation between the actual operating speed (actual speed) of the hydraulic actuators (10, 11, 12) and the target operating speed vref of the hydraulic actuators. The actuator control unit 133 outputs a control signal (e.g., control current) corresponding to the command value to the control valve unit 23. Such a control method for hydraulic actuators is well known, therefore detailed description is omitted.

[0114] The predictive control unit 132 is configured to calculate the control input U by solving the optimization problem of equation (12). * However, the optimization calculation of the predictive control unit 132 may become unstable if the operator sets the target surface St to a position higher than the tip of the bucket 8, or if the GNSS positioning status deteriorates during the operation of the hydraulic excavator 1, causing the state variable x(k) at the current time point (k) to deviate from the constraints. As a result, the operation of the hydraulic excavator 1 may become unstable.

[0115] Under conditions of unstable optimization calculation, based on the calculated control input U... * If the hydraulic excavator 1 continues to operate, the constraint condition of equation (11) cannot be guaranteed to hold. Furthermore, it may be impossible to reduce the value of the evaluation function J in equation (9), and the position of the tooth tip of the bucket 8 may be far from the target tooth tip coordinate ξr. Obviously, neither of these is ideal behavior.

[0116] To reliably avoid such a situation, when the departure determination unit 131 determines that the constraint condition (equation (11)) has been lost, the calculation condition modification unit 134 modifies the calculation condition to prohibit or stop the operation of the hydraulic excavator 1. For example, the calculation condition modification unit 134 modifies the control input U calculated by the predictive control unit 132. * The coverage is 0. The control input calculated by the predictive control unit 132 is the target operating speed of the hydraulic actuators (10, 11, 12). Therefore, by making the control input U... *A value of 0 indicates that the operation of the hydraulic actuators (10, 11, 12) can be prohibited or stopped. That is, if the hydraulic excavator 1 is stopped and the constraint condition is broken, even if the operator begins operation, the hydraulic excavator 1 cannot be moved, and the stopped state is maintained. In other words, the operation of the stopped working device 41 is prohibited. Furthermore, if the constraint condition is broken during the operation of the hydraulic excavator 1, the operation of the hydraulic excavator 1 will stop even if the operator continues operation. Thus, the calculation condition change unit 134 and the predictive control unit 132 perform operation prohibition control to prohibit or stop the operation of the hydraulic excavator 1 when the constraint condition is broken.

[0117] Furthermore, according to the program stored in the controller 100, as described above, if the control input U is... * If the coverage is 0, a division by zero (error) may occur during the calculation. Therefore, the following method is preferred as a method for controlling the prohibition of action. When the separation judgment unit 131 determines that the constraint condition (equation (11)) has been separated, the calculation condition change unit 134 invalidates the constraint condition (equation (11)) related to the tooth tip position. In order to invalidate the constraint condition, instead of the constraint condition of equation (11), an obvious constraint condition such as the following equation (13) that must be satisfied can be set. The calculation condition change unit 134 performs the calculation process of invalidating the constraint condition and substituting the tooth tip coordinate ξ(k) at the current time point into the tooth tip target coordinate ξr(k).

[0118]

[0119] Therefore, the deviation e(k) of equation (9) calculated by the predictive control unit 132 becomes 0, and the control input U * =0 is calculated as an obvious solution. Using this method, the operation of the hydraulic actuator is also prohibited, thus avoiding unwanted actions.

[0120] When the above-mentioned action prohibition control (stop control) is executed, the operation of the hydraulic excavator 1 stops regardless of whether there is a lever operation. Therefore, the operator can anticipate that some kind of abnormality has occurred. Therefore, when the disengagement judgment unit 131 determines that the constraint condition (equation (11)) has been disengaged, the attention reminder unit 141 notifies the operator of the reason for the stoppage of the hydraulic excavator 1 via the user interface 19. The attention reminder unit 141 displays, for example, an illustration showing that the tip of the bucket 8 is located below the target digging surface Se, and a message on the display screen of the user interface 19 (display device 19b). In this way, when the disengagement judgment unit 131 determines that the constraint condition has been disengaged, the attention reminder unit 141 performs output control (notification control) to output the judgment result to the user interface (notification device) 19.

[0121] Furthermore, in the event of a breach in the constraint conditions, the aforementioned action prohibition control may be omitted, and only the output control (notification control) based on the attention activation unit 141 may be executed. In this case, the attention activation unit 141 causes the display screen of the display device 19b to display an attention activation screen to notify the operator that an abnormality has occurred. Additionally, the attention activation unit 141 may also control the speaker provided on the user interface 19 to alert the operator's attention through sound output from the speaker. Thus, the operator can interrupt lever operation until the constraint conditions are restored (until the abnormality is cleared). As a result, unstable operation of the hydraulic excavator 1 can be prevented.

[0122] Next, use Figure 5 An example of the processing sequence of the controller 100 in the first embodiment will be described. Figure 5 This is a flowchart illustrating one example of the processing sequence of the controller 100. However, the processing sequence of the controller 100 in this embodiment is not limited to... Figure 5 The flowchart shown illustrates the processing sequence. Figure 5 The process shown in the flowchart begins when the ignition switch of the hydraulic excavator 1 is turned on, and is repeatedly executed at predetermined calculation cycles.

[0123] like Figure 5 As shown, in step S110, the controller 100 (positioning calculation unit 101) acquires sensor data representing the position detected by the position detection device 35 and sensor data representing the posture (angle, etc.) detected by the posture detection device 29.

[0124] In the next step S115, the controller 100 (state calculation unit 111) calculates the posture state and working state of the hydraulic excavator 1 based on the position information (coordinates of antennas 36 and 37, etc.) and attitude information (angles of driven components, etc.) obtained in step S110. In the posture state calculation of the hydraulic excavator 1, for example, the three-dimensional coordinates of predetermined parts of the hydraulic excavator 1, such as the tips of the bucket 8, the boom 6, and a portion of the stick 7, are calculated. In the working state calculation of the hydraulic excavator 1, for example, the working state quantities (actual speed and other action information at the calculation time) of each hydraulic actuator (4, 10, 11, 12, 14a) are calculated using the detection information from the posture detection device 29.

[0125] In the next step S120, the controller 100 (target data calculation unit 121) refers to the calculation results in step S115, namely the coordinates of the predetermined part of the hydraulic excavator 1 and the coordinates of the tooth tip of the bucket 8, and selects the target excavation surface Se based on the construction information obtained from the construction management system and the like.

[0126] In the next step S125, the controller 100 (target data calculation unit 121) calculates the target speed Vt of the bucket 8 tip, which satisfies predetermined conditions and corresponds to the operation of the operating devices 18a and 18b, based on the position of each part of the hydraulic excavator 1 at the current time point calculated in step S115 and the target excavation surface Se selected in step S120.

[0127] Furthermore, the controller 100 (target data calculation unit 121) calculates the time series data of the target tooth coordinate ξr of the tooth tip of the bucket 8 from the calculation time point (time k) to N steps ago (the predetermined time target) based on the target speed Vt of the tooth tip of the bucket 8 and the tooth tip coordinate ξ of the bucket 8 at the current time point calculated in step S115.

[0128] In the next step S130, the controller 100 (constraint setting unit 122) sets constraints based on the position of the target excavation surface Se set in step S120 (Equation (11)).

[0129] In the next step S135, the controller 100 (disengagement determination unit 131) determines whether the constraint condition set in step S130 is valid based on the tooth tip coordinate ξ of the bucket 8 calculated in step S115 and the constraint condition equation (11). If the constraint condition is valid, that is, if no constraint disengagement occurs, the process proceeds to step S140. If the constraint condition is invalid, that is, if constraint disengagement occurs, the process proceeds to step S150.

[0130] In step S140, the controller 100 (predictive control unit 132) uses the tooth tip coordinate ξ(k) of the bucket 8 at the calculation time (step k) calculated in step S115, the time series data of the target tooth tip coordinate ξr of the bucket 8 calculated in step S125, and the constraint conditions determined in step S130 to calculate the target motion speed vref of each hydraulic actuator (10, 11, 12) as the control input u by calculation based on the prediction model (e.g., the calculation of the above formula (12)).

[0131] In step S150, the controller 100 (calculation condition change unit 134) performs a calculation process that changes the constraint condition determined in step S130 from equation (11) to equation (13) and substitutes the current tooth tip coordinate ξ(k) into the tooth tip target coordinate ξr(k).

[0132] In the next step S160, the controller 100 (attention alerting unit 141) outputs a display control signal to the display device 19b, including an image notifying that a constraint detachment has occurred, to display an attention alerting screen. This displays the attention alerting screen on the display device 19b, alerting the operator. After the notification of the detachment (the process in step S160), the process proceeds to the aforementioned step S140.

[0133] If the predictive control calculation process (step S140) is completed, the process proceeds to step S145. In step S145, the controller 100 (actuator control unit 133) outputs a control signal corresponding to the target operating speed vref of each hydraulic actuator (10, 11, 12) calculated in step S140 to the controlled object (control valve unit 23). As a result, each hydraulic actuator 10, 11, 12 is driven according to the control signal.

[0134] Upon completion of step S145, one control cycle ends, and controller 100 transitions to the next control cycle. That is, the processes following step S110 are executed again in the next control cycle. Furthermore, the above processing flow is an example, and the order can be appropriately changed. For example, the order of steps S150 and S160 can be reversed, or they can be processed in parallel. Additionally, in Figure 5 The example illustrates the following: In the event of constraint decoupling, to modify the constraint equations and make the deviation e(k) zero, predictive control operations are performed based on the calculation of substituting the current tooth tip coordinates ξ(k) into the target tooth tip coordinates ξr(k). However, these operations can be substituted instead by performing operations that make the control input U... * A process where the value is 0. In this case, the predictive control operation is omitted.

[0135] According to the above implementation method, the following effects are achieved.

[0136] (1) The hydraulic excavator (operating machinery) 1 has an operating device 41 and a body 42 on which the operating device 41 is mounted. The operating device 41 has multiple driven components (bucket 8, stick 7 and boom 6) including a bucket (operating tool) 8 and multiple hydraulic actuators (bucket cylinder 12, stick cylinder 11 and boom cylinder 10) for driving the multiple driven components. The hydraulic excavator 1 has a posture detection device 29 for detecting the posture of the operating device 41, a position detection device 35 for detecting the position of the body 42, and a controller 100 for controlling the movement of the operating device 41.

[0137] The controller 100 calculates the coordinates of the bucket 8 at the current time point based on the posture of the working device 41 detected by the posture detection device 29 and the position of the machine body 42 detected by the position detection device 35. Figure 5 S110, S115). Based on the coordinates of the bucket 8 and the boundary surface of the action-limiting area A1 that allows the operation of the working device 41 and the intrusion prevention area A2 that prevents the intrusion of the working device 41, i.e., the target excavation surface Se, the controller 100 sets constraints in the model predictive control to prevent the working device 41 from intruding into the intrusion prevention area A2. Figure 5 S130). The controller 100 performs model predictive control of the target motion speed vref of the hydraulic actuators (10, 11, 12) for a predetermined time period from the current time point, in a manner that satisfies the constraints and the deviation e between the coordinates (tooth tip coordinate ε) of the bucket 8 and the target coordinates (tooth tip target coordinate εr) of the bucket 8 decreases. Figure 5 (S140). The controller 100 calculates the operating speed of the hydraulic actuators (10, 11, 12) based on the posture of the working device 41 detected by the posture detection device 29. Figure 5 (S115). Controller 100 controls the hydraulic actuators to make the operating speed of the hydraulic actuators (10, 11, 12) match the target operating speed. Figure 5 (S145).

[0138] The controller 100 determines whether the position of the control point of the working device 41 (e.g., the tip of the teeth of the bucket 8, the back of the bucket 8) has deviated from the constraint conditions. Figure 5 S135). For example, if the controller 100 determines that the position of the control point of the working device 41 is out of the constraint condition due to the target excavation face Se being set such that the coordinates of the bucket 8 are located in the intrusion prevention zone A2, or due to the deterioration of the GNSS positioning status (the detection accuracy of the position detection device 35), the controller 100 executes output control to output the determination result to the user interface (notification device) 19. Figure 5 S160), and performs action prohibition control to prohibit or stop the operation of the working device 41 ( Figure 5 (S150, S140). According to this structure, unstable operation of the hydraulic excavator 1 can be prevented.

[0139] Furthermore, an example has been described in which the controller 100 of this embodiment performs both output control to alert the operator and motion prohibition control to forcibly prohibit or stop the operation of the hydraulic excavator 1. However, the controller 100 may also perform only either output control or motion prohibition control. For example, in the case of performing only output control, the operator can be aware that a constraint has been breached. The operator can interrupt the operation as needed, thus preventing unstable operation of the hydraulic excavator 1. In addition, in the case of performing only motion prohibition control, the working device 41 automatically stops, thus preventing unstable operation of the hydraulic excavator 1.

[0140] (2) For example, in motion prohibition control, the controller 100 sets the target motion speed vref of the hydraulic actuators (bucket cylinder 12, boom cylinder 11, and boom cylinder 10) to 0. The controller 100 controls the hydraulic actuators (10, 11, 12) in such a way that the motion speed of the hydraulic actuators (10, 11, 12) is consistent with the target motion speed vref. Therefore, by setting the target motion speed vref to 0, the action of the hydraulic actuators (10, 11, 12) can be prohibited or stopped.

[0141] (3) For example, in motion prohibition control, the controller 100 sets the target coordinates (tooth tip target coordinates ξr) of the bucket 8 at the current time point to the target coordinates (tooth tip target coordinates ξr) of the bucket 8, and invalidates the constraint conditions (equation (11)) under normal control. The controller 100 invalidates the constraint conditions under normal control by changing the expression of the constraint conditions from expression (11) under normal control to expression (13) under motion prohibition control. According to this structure, the risk of generating adverse situations (errors caused by division by zero) in the calculation processing of the controller 100 can be reduced, and the operation of the hydraulic actuators (10, 11, 12) can be prohibited or stopped.

[0142] <Second Implementation Method>

[0143] Reference Figures 6A to 10A The hydraulic excavator 1 according to the second embodiment of the present invention will be described. Furthermore, reference numerals are used for structures that are the same as or equivalent to those described in the first embodiment, and the main differences will be explained. In the first embodiment, an example was described where the target excavation surface Se, which serves as the boundary between the action-limiting region A1 and the intrusion prevention region A2, is set inside the object being excavated (e.g., the ground). In contrast, in the second embodiment, the intrusion prevention surface Sp, which serves as the boundary between the action-limiting region A1 and the intrusion prevention region A2, is set in the air.

[0144] For example, such as Figure 6A As shown, in a confined work area where a hydraulic excavator 1 and worker 50 are performing trenching operations, the controller 200 (refer to...) Figure 7 An intrusion prevention surface Sp is provided in front of the hydraulic excavator 1. The intrusion prevention surface Sp is positioned between the hydraulic excavator 1 and the operator 50. Therefore, the area closer to the operator 50 than the intrusion prevention surface Sp is defined as the intrusion prevention area A2, and the area closer to the hydraulic excavator 1 than the intrusion prevention surface Sp is defined as the action restriction area A1.

[0145] In the second embodiment, the constraints for model predictive control are set based on the position of the intrusion prevention surface Sp. This prevents the working device 41 from coming into contact with the worker 50. Furthermore, unlike the target excavation surface Se described in the first embodiment, even if the working device 41 intrudes into the intrusion prevention area A2, no immediate problem will occur. For example, as... Figure 6B As shown, even if the working device 41 intrudes into the intrusion prevention zone A2 before the operator 50 arrives at the work site, there is no particular problem. Conversely, in such a situation, if the operation of the hydraulic excavator 1 is prohibited as in the first embodiment, the work efficiency may decrease. Therefore, in the second embodiment, a constraint condition is set based on the position of the intrusion prevention surface Sp, and control that prevents a decrease in work efficiency is executed when the constraint condition is broken. Hereinafter, the control content of the second embodiment will be described in detail.

[0146] Figure 7 This is a block diagram illustrating the detailed functions of the controller 200 in the second embodiment. The controller 200, like the controller 100 in the first embodiment, has the function of setting a target digging surface Se and controlling each hydraulic actuator to move the tips of the bucket 8 along the target digging surface Se.

[0147] The target setting unit 102 not only sets the target excavation surface Se, but also sets the intrusion prevention surface Sp, and determines the constraint conditions corresponding to the intrusion prevention surface Sp. The intrusion prevention surface Sp is set to not include obstacles that the hydraulic excavator 1 cannot access. Examples of obstacles include workers 50, walls, overhead power lines, and work vehicles (dump trucks, wheel loaders). The motion restriction area A1 is not a specific part of the hydraulic excavator 1, but rather an area where the entire constituent parts of the hydraulic excavator 1 cannot be detached. That is, the motion control of the hydraulic excavator 1 is not only... Figure 6A as well as Figure 6B The front end position P0 and the back end position P1 of the bucket 8 of the working device 41 shown, as well as the position P2 of the connecting pin at the front end of the bucket cylinder 12 or the position P3 of the connecting pin at the front end of the boom cylinder 11, etc., also need to be operated in a manner that does not leave the action limitation area A1.

[0148] The target data calculation unit 221 sets an intrusion prevention surface Sp based on construction information from the construction management system (not shown) or input information (construction information set by the operator) from the user interface 19 (input device 19a). If the construction information includes information about obstacles, the target data calculation unit 221 automatically sets the intrusion prevention surface Sp between the hydraulic excavator 1 and the obstacle. Regarding the target data calculation unit 221, if the construction information does not include information about obstacles, or if there are moving obstacles such as work vehicles around the hydraulic excavator 1, the operator sets the intrusion prevention surface Sp via the user interface 19.

[0149] The constraint setting unit 222 determines the constraint conditions based on the position of the intrusion prevention surface Sp set by the target data calculation unit 221. For example, ... Figure 6A As shown, the case where the intrusion prevention surface Sp is assigned by a vertical plane (a plane parallel to the direction of gravity) orthogonal to the front-back direction of the rotating body 3 will be explained. In the example shown, the position of the intrusion prevention surface Sp is x = xd. Therefore, the constraint condition can be expressed by the formula (x(k) ≤ xd) indicating that the x-coordinate x(k) of the control point P of the bucket 8 (e.g., the front end position P0 of the bucket 8) is less than the x-coordinate xd of the intrusion prevention surface Sp. Furthermore, the contact judgment of obstacles, etc., is not limited to the front end of the bucket 8, and it is necessary to note that any part of the hydraulic excavator 1 is the object. The constraint condition corresponding to the intrusion prevention surface Sp can be expressed as the general expression formula (14) by using the function d.

[0150]

[0151] The detachment determination unit 231 uses the coordinates of the control points P0 and P1 of the bucket 8 and the constraint equation (11) to determine whether a detachment based on the constraint of the target excavation surface Se has occurred. Furthermore, the detachment determination unit 231 uses the coordinates of the control points P0, P1, P2, and P3 of the bucket 8 and the constraint equation (14) to determine whether a detachment based on the constraint of the intrusion prevention surface Sp has occurred.

[0152] The calculation condition modification unit 234 modifies the calculation conditions for model predictive control when the departure determination unit 231 confirms that a departure from the constraint conditions has occurred, and the departure aligns with the operator's intention. For example, such as... Figure 6B As shown, this is a function that assists the operation of the working device 41 so that the operator can start the grooving operation from a state where a part of the working device 41 has entered the intrusion prevention area A2, and the working device 41 is housed within the action limitation area A1.

[0153] The calculation condition modification unit 234, based on the input information from the input device 19a, determines whether the detachment of the constraint conditions of the intrusion prevention surface Sp is in accordance with the operator's intention, that is, whether the operator intends to operate the work device 41. A specific example will be described below. If the detachment judgment unit 231 confirms that the work device 41 has detached from the operation limitation area A1 (i.e., intruded into the intrusion prevention area A2), the attention awakening unit 241 outputs a display control signal for an attention awakening screen to the display device 19b to awaken the operator's attention.

[0154] Figure 8 This diagram illustrates an example of an attention-awakening screen displayed on the user interface (touch panel monitor) 19. For example... Figure 8 As shown, when the display device 19b receives a display control signal, it displays an attention-awakening screen corresponding to the display control signal on the display screen.

[0155] The user interface 19 displays three images: a disengagement notification image (POP1), an intention confirmation image (POP2), and a selection image (POP3). The disengagement notification image (POP1) indicates that a portion of the hydraulic excavator 1 has disengaged from the action-limited area A1, i.e., a disengagement from the constraint conditions has occurred. For example, it displays a message such as, "The vehicle has stopped because disengagement has been confirmed." The intention confirmation image (POP2) is used to confirm with the operator whether the disengagement aligns with the operator's intention. For example, it displays a message such as, "Is the auxiliary control to eliminate disengagement active?" Thus, the user interface 19 notifies the operator of information indicating that the control point P of the working device 41 has disengaged from the constraint conditions (disengagement notification image POP1) and information confirming the operator's intention to activate the working device 41 (intention confirmation image POP2).

[0156] The selection image POP3 is an image indicating whether the removal of a constraint aligns with the operator's intention, for example, it includes a positive operation image "Yes" and a negative operation image "No". In this embodiment, the user interface 19 is a touch panel monitor. Therefore, the operator can indicate whether the removal of the constraint is intended by touching either the positive or negative operation image. When the positive operation image is touched, the user interface 19 outputs a positive operation signal to the controller 200; when the negative operation image is touched, it outputs a negative operation signal to the controller 200. When the user interface 19 has a structure with a monitor and physical input switches (buttons or a keyboard), the display of the selection image POP3 can be omitted. The positive operation signal is equivalent to an operation signal indicating that the operator intends to operate the work device 41, and the negative operation signal is equivalent to an operation signal indicating that the operator does not intend to operate the work device 41. Furthermore, the positive operation signal is an operation signal used to restore the work device 41 to a state where it can operate normally; therefore, it can also be described as a restoration operation signal.

[0157] When the departure determination unit 231 determines that a departure of the constraint condition (equation (14)) has occurred, the calculation condition modification unit 234 performs a first calculation condition modification process. In the first calculation condition modification process, the calculation condition modification unit 234 performs an operation that changes the constraint condition from equation (14) to the following obvious constraint condition (15), and substitutes the current tooth tip coordinate ξ(k) into the tooth tip target coordinate ξr(k). This process is equivalent to setting a condition that prohibits the operation of the hydraulic excavator 1. As a result, the operation of the hydraulic excavator 1 is prohibited. That is, the stopped state of the hydraulic excavator 1 is maintained until the departure of the constraint condition (equation (14)) is eliminated, or the above-mentioned positive operation signal is input to the controller 200.

[0158]

[0159] If the calculation condition modification unit 234 receives a negative operation signal from the user interface 19, it determines that the departure of the constraint condition does not conform to the operator's intention. In this case, the operation of the hydraulic excavator 1 is prohibited.

[0160] When the calculation condition modification unit 234 receives a positive operation signal from the user interface 19, it determines that the departure of the constraint condition is in accordance with the operator's intention. When the departure determination unit 231 determines that a departure of the constraint condition has occurred and that the departure is in accordance with the operator's intention, the calculation condition modification unit 234 executes a second calculation condition modification process. In the second calculation condition modification process, the calculation condition modification unit 234 modifies the calculation conditions of the model predictive control so that each control point P0, P1, P2, and P3, including the tip position (front end position) of the bucket 8, converges within the action limitation region A1. Hereinafter, refer to... Figure 9A as well as Figure 9B The changes to the second calculation conditions are explained in detail. Additionally, the constraints on the actual action-limiting region A1 are also referred to as the baseline constraints.

[0161] Figure 9A This diagram shows the state where the bucket has disengaged from the actual motion-limited area A1. Figure 9B This diagram illustrates the alternative constraints set to bring the bucket closer to the actual motion limit region A1. These alternative constraints are other constraints different from equation (14) above. Figure 9A In the example shown, the intrusion prevention surface Sp of the actual action-limited region A1 is set to x = xd. The expression for the basic constraint is, for example, x ≤ xd. Figure 9A In the example shown, the x-coordinate of the control point P1 of the bucket 8 is xp1 (>xd). In the second calculation condition change process, the calculation condition change unit 234 sets a substitute constraint to replace the obvious constraint set in the first calculation condition change process. The formula for the substitute constraint is, for example, x≤xd′. The initial value of xd′ is set to xp1. That is, the calculation condition change unit 234 sets the substitute constraint (x≤xd′) in such a way that the intrusion prevention surface Sp′ is set at the position of the control point P1 at this time. This intrusion prevention surface Sp′ is the surface that defines the provisional action restriction area A1′ that temporarily allows action, and is therefore also referred to as the provisional intrusion prevention surface Sp′ below. The calculation condition change unit 234 changes the substitute constraint so that the provisional intrusion prevention surface Sp′ gradually approaches the intrusion prevention surface Sp (hereinafter also referred to as the reference intrusion prevention surface Sp) that defines the actual action restriction area A1.

[0162] Specifically, as shown in the following equation (16), the calculation condition change unit 234 sets the constraint condition in such a way that the time passes and the actual action limit region A1 is closer.

[0163]

[0164] Here, α is a parameter that adjusts the speed at which the current position of the bucket 8 approaches the action limit area A1. If the action speed of the control point P1 of the bucket 8 is set to vdes, then the control cycle Δt can be defined as "α = vdes × Δt". That is, in each control cycle (unit of time) Δt, the temporary intrusion prevention surface Sp′ shifts to the left by a distance α as shown in the figure. As time passes, the temporary intrusion prevention surface Sp′ gradually approaches the reference intrusion prevention surface Sp and becomes consistent with the reference intrusion prevention surface Sp.

[0165] Thus, the controller 200 of this second embodiment controls the hydraulic actuators (10, 11, 12) using model predictive control with alternative constraint conditions. Therefore, as... Figure 9B As shown, in order to satisfy the substitution constraint conditions at each moment, the position of the bucket 8 gradually approaches the actual action limit area A1 (x = xd), and finally becomes the posture of the working device 41 housed in the action limit area A1.

[0166] In addition, Figure 9A In the diagram, P1 represents the rear position of the bucket 8, but other coordinates of the working device 41 can also be used as control points. Additionally, in... Figure 9A The example shown is a single control point, but the above control can also be performed based on multiple control points.

[0167] When the disengagement determination unit 231 determines that no disengagement has occurred due to constraint conditions, the predictive control unit 232 calculates the control input U using equation (17) obtained by adding the constraint conditions (equation (14)) of the action limitation region A1 to equations (12) and (9) of the model predictive control in the first embodiment. * .

[0168]

[0169] When the disengagement determination unit 231 determines that a disengagement from the constraint condition (equation (14)) has occurred, and determines that the occurrence of the disengagement is in line with the operator's intention, the predictive control unit 232 calculates the control input U using the equation (18) set by the calculation condition change unit 234 to replace the constraint condition. * Furthermore, d′ in (18a) of equation (18) is equivalent to replacing the constraint condition.

[0170]

[0171] The above method illustrates an example of adjusting the position of the working device 41 by changing the constraints (making the substitute constraints effective). However, the control method for containing the working device 41 within the actual motion-limited area A1 is not limited to this. For example, the movement of the working device 41 can also be controlled by changing the target coordinate ξr of the tooth tip of the bucket 8 so that the working device 41 is contained within the actual motion-limited area A1.

[0172] For example, the calculation condition change section 234 Figure 9A As shown, at time k0, the actual tooth tip coordinate ξ(k0) of the bucket 8 is set as the target tooth tip coordinate ξr(k0) of the bucket 8. The tooth tip target coordinate set here is a second target coordinate (replacing the tooth tip target coordinate) set separately from the first target coordinate (tooth tip target coordinate) set based on the target excavation surface Se. For example... Figure 9B As shown, the calculation condition change unit 234 gradually brings the target coordinate εr of the tooth tip closer to the actual motion limit area A1 over time. As a result, the working device 41 operates in a manner that is contained within the actual motion limit area A1.

[0173] Furthermore, it is preferable to perform the change of constraint conditions and the change of tooth tip target coordinates simultaneously. That is, when the disengagement judgment unit 231 determines that the disengagement of constraint condition (equation (14)) has occurred, and determines that the occurrence of the disengagement is in line with the operator's intention, the predictive control unit 232 calculates the control input U using the alternative constraint conditions set by the calculation condition change unit 234 and the following equation (19) using the alternative tooth tip target coordinates. * Furthermore, in equation (19), d′ in (19a) is equivalent to replacing the constraint condition, and ξr′ in (19b) is equivalent to replacing the target coordinates of the tooth tip.

[0174]

[0175] Figure 10A Is with Figure 5 The same figure is a flowchart illustrating an example of the processing sequence of the controller 200 in the second embodiment. Figure 10A In the flowchart, instead Figure 5 The flowchart shows the processing of steps S130, S135, S150, and S160, and the processing of steps S230, S235, S250, S260, S265, and S275.

[0176] In step S230, the controller 200 (constraint setting unit 222) sets the constraint conditions (equation (11)) through the same process as in step S130, and sets the constraint conditions (equation (14)) based on the position of the intrusion prevention surface Sp set by the target data calculation unit 221.

[0177] In the next step S235, the controller 200 (disengagement determination unit 231) determines whether a constraint disengagement has occurred based on the position of the tooth tip of the bucket 8 calculated in step S115 and the constraint conditions (11) and (14) set in step S230. If it is determined that no constraint disengagement has occurred, the process proceeds to step S140.

[0178] Furthermore, although not illustrated, in step S235, if it is determined that a detachment from the constraint condition (equation (11)) has occurred, the same procedure as in the first embodiment is followed. Figure 5 The processing of steps S150 and S160. In step S235, if it is determined that the constraint condition (equation (14)) has been detached, the processing proceeds to step S250.

[0179] In step S250, the controller 200 (calculation condition change unit 234) performs a calculation process that changes the constraint condition determined in step S230 from equation (14) to equation (15), and substitutes the current tooth tip coordinate ξ(k) into the tooth tip target coordinate ξr(k). Furthermore, in step S250, the controller 200 (predictive control unit 232, actuator control unit 133) performs the same processing as in steps S140 and S145. That is, step S250 is equivalent to motion prohibition control.

[0180] In the next step S260, the controller 200 (attention-awakening unit 241) outputs a display control signal to the user interface 19, including an image notifying that a constraint has been escaped. As a result, the display screen on the display device 19b displays... Figure 8 The screen shown is designed to draw attention.

[0181] In the next step S265, the controller 200 (calculation condition change unit 234) determines, based on the operation signal corresponding to the selected image POP3, whether the release of the constraint condition conforms to the operator's intention, i.e., whether the operator intends to operate the work device 41. If a positive operation signal (recovery operation signal) is input from the input device 19a, the controller 200 (calculation condition change unit 234) determines that the release of the constraint condition conforms to the operator's intention and proceeds to step S275. If a negative operation signal is input from the input device 19a, the controller 200 (calculation condition change unit 234) determines that the release of the constraint condition does not conform to the operator's intention and returns the process to step S235. Furthermore, although not shown, this determination process can be repeatedly executed when a negative operation signal is input until it is determined in the release determination process (step S235) that no release of the constraint condition has occurred.

[0182] In step S275, the controller 200 (calculation condition change unit 234) changes the constraint condition determined in step S250 from equation (15) to equation (19a). This process is equivalent to setting the conditions for guiding the working device 41 to the actual action-limited area A1.

[0183] In the next step S140, the predictive control unit 232 performs predictive control calculations based on either the constraint conditions set in step S230 or the constraint conditions set in step S275.

[0184] According to the second embodiment, in addition to the same effects as the first embodiment, it also has the following effects.

[0185] (4) The hydraulic excavator 1 has a user interface 19. The user interface 19 has an input device (e.g., a touch sensor) 19a operated by the operator and a notification device for notifying the operator. The notification device includes a display device (monitor) 19b and a sound output device (speaker). When the controller 200 determines that the position of the control point P (P0 to P3) of the working device 41 has deviated from the constraint condition, it executes output control ( Figure 10A S260) and motion prohibition control ( Figure 10A (S250).

[0186] In output control, the controller 200 notifies the operator via the user interface (notification device) 19 that the position of control point P (P0~P3) of the working device 41 has deviated from the constraint conditions. Figure 8 The detachment notification image POP1 and the information confirming the intention to activate the working device 41 ( Figure 8 (Intention confirmation image POP2 and selection image POP3) Figure 10A (S260).

[0187] When the controller 200 determines that the position of the control point P (P0~P3) of the working device 41 is out of the constraint condition, and upon inputting an operation signal (affirmative operation signal) indicating that the operator intends to move the working device 41, it releases the action prohibition control, invalidates the constraint condition, and sets the target coordinates of the tip of the bucket 8 in a manner that brings the control point P (P0~P3) of the working device 41 close to the action limitation area A1. Figure 9A , Figure 9B , Figure 10A (S265, S275, S140). Touch operation Figure 8 When the selected image POP3 is the positive operation image, a positive operation signal is output from the user interface 19 to the controller 200.

[0188] According to this structure, the operation of the working device 41 is prohibited at the moment when the constraint condition is broken, thus effectively preventing unstable operation of the hydraulic excavator 1. In addition, according to this structure, when there are no obstacles around the hydraulic excavator 1, the hydraulic actuator can be operated by the operator as needed to retract the working device 41 into the operation limitation area A1.

[0189] <Modifications of the Second Embodiment>

[0190] The processing order of controller 200 can also be changed as follows. Figure 10B Is with Figure 10A The same figure is a flowchart illustrating an example of the processing sequence of the controller 200 in a modified embodiment of the second implementation. Figure 10B In the flowchart, omitting Figure 10A The process of step S250 in the flowchart is processed, and if the determination in step S265 is negative, the process of step S270 is executed.

[0191] In the second embodiment described above, the controller 200 performs output control (notification control) and action prohibition control when it determines that the position of the control point P of the working device 41 is out of the constraint conditions. In contrast, in this modified example, the controller 200 only performs output control (notification control) when it determines that the position of the control point P of the working device 41 is out of the constraint conditions. If a negative operation signal indicating that the operator has not activated the working device 41 is input, it performs action prohibition control (…). Figure 10B (S265, S270, S140, S145). When touch operation... Figure 8 When the selection image POP3 is the negative operation image, the negative operation signal is output from the user interface 19 to the controller 200.

[0192] (5) When the controller 200 determines that the position of the control point P of the working device 41 has deviated from the constraint condition, it executes output control. Figure 10B (S260). In output control, the controller 200 notifies the operator via the user interface (notification device) 19 of information indicating that the position of the control point P of the working device 41 has escaped the constraint conditions and information confirming the intention to operate the working device 41. When the controller 200 determines that the position of the control point P of the working device 41 has escaped the constraint conditions, upon inputting a positive operation signal indicating that the operator intends to operate the working device 41, it invalidates the constraint conditions and sets the target coordinates of the tip of the bucket 8 in a manner that brings the control point P of the working device 41 closer to the action limitation area A1. Figure 10B (S235, S265, S275).

[0193] When the controller 200 determines that the position of the control point P of the working device 41 has deviated from the constraint condition, and a negative operation signal indicating that the operator has not intended to operate the working device 41 is input, the controller 200 executes the action prohibition control. Figure 10B (S265, S270, S140, S145). According to this structure, when there are obstacles around the hydraulic excavator 1, the operation of the hydraulic excavator 1 can be stopped by the operator as needed. In addition, when there are no obstacles around the hydraulic excavator 1, the hydraulic actuator can be operated by the operator as needed to house the working device 41 within the operation limitation area A1.

[0194] <Third Implementation Method>

[0195] Reference Figure 11 The hydraulic excavator 1 according to the third embodiment of the present invention will be described. Furthermore, reference numerals are used for structures that are the same as or equivalent to those described in the first embodiment, and the main differences will be explained. In the first embodiment, an example of operating the hydraulic excavator 1 by operating the operating devices 18a, 18b, and 18c within the cab 16 was described. In contrast, in the third embodiment, an example of automatically operating the hydraulic excavator 1 without operator intervention will be described.

[0196] Figure 11 This is a block diagram illustrating the detailed functions of the controller 300 in the third embodiment. For example... Figure 11 As shown, in the case of automatic driving, since it does not rely on operator intervention, operating devices 18a and 18b are not required (see reference). Figure 3 Furthermore, since the operator is not present, there is no need to notify the operator of the release of the constraint. Therefore, there is no need to use the display device 19b to draw the operator's attention.

[0197] The target data processing unit 321 automatically determines the digging start position based on the posture of the hydraulic excavator 1 calculated by the state processing unit 111 and the construction information obtained from the external construction management system 51, and outputs the digging start position as the target coordinate of the tooth tip. For example, as Figure 4A as well as Figure 4B As shown, the target coordinates of the tooth tip are preferably set as the point (closest point) within the target digging surface Se that is closest to the tooth tip of the bucket 8. The target data processing unit 321 draws a perpendicular line to the target digging surface Se, and sets the intersection point (closest point) of the perpendicular line and the target digging surface Se as the target coordinates of the tooth tip.

[0198] When the hydraulic excavator 1 is in automatic driving mode, the operator does not set the target excavation surface Se on site. Therefore, the situation where the constraint condition is lost mainly becomes the situation where the state calculation unit 111 generates calculation errors caused by GNSS positioning errors. Therefore, in the event of constraint condition loss, it is preferable to stop the operation of the hydraulic excavator 1 and wait for the GNSS positioning state to be restored.

[0199] The calculation condition modification unit 334 determines whether the detection accuracy (i.e., GNSS positioning status) of the position detection device 35 is good based on the detection signal from the position detection device 35, and modifies the calculation conditions corresponding to the determination result. For example, the calculation condition modification unit 334 receives the positioning status (communication strength, etc.) from the position detection device 35, and similarly to the first embodiment, sets the current tooth tip position as the tooth tip target coordinate and changes the constraint condition from equation (11) to equation (13), so that the control input U * The value becomes 0 until the positioning state is restored (until the communication strength reaches a predetermined value or higher). Upon restoration of the positioning state, i.e., when the communication strength reaches a predetermined value or higher, the calculation condition change unit 334 releases the control input U used to achieve the aforementioned value. * Changes to constraints with a value of 0, etc. That is, the action prohibition control is released, and the constraint condition returns from Equation (13) to Equation (11). As a result, the working device 41 is controlled again to make the tip of the bucket 8 move along the target digging surface Se.

[0200] Furthermore, the method for determining whether the detection accuracy of the position detection device 35 is good is not limited to the case where it is based on the communication strength, that is, the value of the reception strength of each positioning satellite included in the GNSS data. The calculation condition change unit 334 may also determine whether the detection accuracy of the position detection device 35 is good based on the value of DOP (Dilution of Precision), which indicates the configuration status of the satellites.

[0201] According to this third embodiment, it has the same effect as the first embodiment, and has the following effects.

[0202] (6) The position detection device 35 receives signals from GNSS satellites to detect the position of the machine body 42. If the controller 300 determines that the position of the control point P of the working device 41 has deviated from the constraint conditions, it executes an action prohibition control. Based on the signals from the position detection device 35, the controller 300 determines whether the detection accuracy of the position detection device 35 is good. If the controller 300 determines that the detection accuracy of the position detection device 35 is poor, it continues the action prohibition control. If the controller 300 determines that the detection accuracy of the position detection device 35 is good, it releases the action prohibition control. According to this structure, in the event of a deviation from the constraint conditions due to a decrease in the detection accuracy of the position detection device 35, the operation of the hydraulic excavator 1 can be prohibited until the detection accuracy becomes good. Therefore, unstable actions during automatic driving can be effectively prevented.

[0203] Furthermore, in this third embodiment, the case of enabling the hydraulic excavator 1 of the first embodiment to have an automatic driving function has been described as an example, but the case of enabling the hydraulic excavator 1 of the second embodiment to have an automatic driving function is the same.

[0204] <Fourth Implementation Method>

[0205] Reference Figure 12 The hydraulic excavator 1 according to the fourth embodiment of the present invention will be described. Furthermore, reference numerals are used for structures that are the same as or equivalent to those described in the second embodiment, and the main differences will be explained. In the third embodiment, an example was described where, in the event of constraint loss due to deterioration of GNSS positioning during automatic driving, the operation of the hydraulic excavator 1 was stopped, and automatic driving was resumed when the GNSS positioning status was restored. In contrast, in the fourth embodiment, in the second embodiment, when the GNSS positioning status deteriorates to the point where constraint loss is possible, the operator is notified of the deterioration of the GNSS positioning status, and the operation of the hydraulic excavator 1 is stopped.

[0206] Figure 12 This is a block diagram illustrating the detailed functions of the controller 400 in the fourth embodiment. The controller 400 has the same functions as the controller 200 described in the second embodiment. Furthermore, the controller 400 monitors the GNSS positioning status in the same way as in the third embodiment. The calculation condition modification unit 434 determines whether the GNSS positioning status is good based on the detection signal from the position detection device 35. For example, the calculation condition modification unit 434 determines whether the GNSS positioning status is good based on the receive strength value of each positioning satellite included in the GNSS data, or the DOP value indicating the satellite configuration status, etc.

[0207] When the calculation condition change unit 434 determines that the GNSS positioning status is good, the predictive control unit 432 performs predictive control based on equation (12). When the calculation condition change unit 434 determines that the GNSS positioning status is not good, it changes the constraint condition from equation (11) to the obvious constraint condition equation (13), and sets the current tooth tip coordinates as the tooth tip target coordinates. Therefore, through the predictive control of the predictive control unit 432, the control input U is... * Become 0.

[0208] When the calculation condition change unit 434 determines that the GNSS positioning status is not good, the attention alerting unit 441 displays an attention alerting screen indicating the determination result on the display screen of the display device 19b. The attention alerting screen indicating the deterioration of the GNSS positioning status includes an image displaying a message such as "Due to the deterioration of the GNSS positioning status, the vehicle should be stopped" (positioning status notification image), an image displaying a message such as "Continue work?" (intention confirmation image), and a selection image indicating the operator's intention to continue work (intention to activate the work device 41). This selection image includes, for example, a positive operation image "Yes" and a negative operation image "No".

[0209] When the operator touches a positive operation image, the input device 19a outputs a positive operation signal to the controller 400. When the operator touches a negative operation image, the input device 19a outputs a negative operation signal to the controller 400.

[0210] When the calculation condition modification unit 434 receives a positive operation signal from the user interface 19, it determines that the operator intends to perform the operation and executes the modification process for the second calculation condition. When the calculation condition modification unit 434 receives a negative operation signal from the user interface 19, it determines that the operator does not intend to perform the operation and does not execute the modification process for the second calculation condition. Without performing the modification process for the second calculation condition, the hydraulic excavator 1 remains in a stopped state until the GNSS positioning state is restored. The modification process for the second calculation condition is the same as in the second embodiment, therefore, its description is omitted.

[0211] According to this fourth embodiment, it has the same effect as the second embodiment, and has the following effects.

[0212] (7) The controller 400 determines whether the detection accuracy (GNSS positioning status) of the position detection device 35 is good based on the detection signal from the position detection device 35. If the controller 400 determines that the detection accuracy of the position detection device 35 is poor, it executes action prohibition control and notification control regardless of whether the position of the control point of the working device 41 is out of the constraint condition. In the notification control, the controller 400 notifies the operator through the user interface (notification device) 19 of the information indicating that the detection accuracy of the position detection device 35 is poor and the information confirming the intention to make the working device 41 move. If the controller 400 determines that the detection accuracy of the position detection device 35 is poor, it releases the action prohibition control and invalidates the constraint condition when an operation signal (affirmation operation signal) indicating that the operator intends to make the working device 41 move is input. According to this structure, the operation of the hydraulic excavator 1 can be prohibited or stopped at the moment when the constraint condition may be out of the control condition, thus more effectively preventing the unstable operation of the hydraulic excavator 1. In addition, the working device 41 can be made to move and continue working even when there are no obstacles around the hydraulic excavator 1.

[0213] The following variations are also within the scope of the present invention. The structures shown in the variations can be combined with the structures described in the above embodiments, or the structures described in the different embodiments described above can be combined with each other, or the structures described in the different variations below can be combined with each other.

[0214] <Variation Example 1>

[0215] In the above-described embodiments, an example of a working tool for the working device 41 is shown, which is a bucket 8 capable of rotating only in the vertical direction around a horizontal axis. However, the working tool may also be a bucket having at least one of a tilting function and a rotating function (such as a rotating tilting bucket).

[0216] <Variation Example 2>

[0217] In the above embodiment, a structure is shown that uses a hydraulic motor (rotary hydraulic motor 4) as the drive source for the rotary drive of the rotary body 3. However, the drive source for rotary drive can also be an electric motor. Alternatively, the drive source for rotary drive can be configured to use both a hydraulic motor and an electric motor.

[0218] <Variation Example 3>

[0219] In the above embodiments, examples are shown where the operating devices 18a, 18b, and 18c for operating the hydraulic actuators are electrically operated. However, the operating devices can also be hydraulically piloted. The hydraulically piloted operating device outputs an operating pilot pressure corresponding to the operating direction and operating amount. This operating pilot pressure acts as a drive signal on the pressure-receiving portion of each control valve in the control valve unit 23. Thus, each hydraulic actuator 4, 10, 11, 12, and 14a is driven according to the operating direction and operating amount of the operating device.

[0220] The embodiments of the present invention have been described above, but the above embodiments only show a part of the application examples of the present invention, and the technical scope of the present invention is not limited to the specific structure of the above embodiments.

[0221] Symbol Explanation

[0222] 1—Hydraulic excavator (operating machinery), 2—Traveling body, 3—Swing body, 6—Boom (driven component), 7—Stick (driven component), 8—Bucket (working tool, driven component), 10—Boom cylinder (hydraulic cylinder, hydraulic actuator), 11—Stick cylinder (hydraulic cylinder, hydraulic actuator), 12—Bucket cylinder (hydraulic cylinder, hydraulic actuator), 18a, 18b, 18c—Operating devices, 19—User interface (notification device, display device, input device, touch panel monitor), 19a—Input device, 19b—Display device, 21—Prime mover, 22—Hydraulic pump unit, 23—Control valve unit, 25-28—Inertial measurement unit, 29—Attitude detection device, 35—Position detection device, 36, 37—GNSS antenna, 38—GNSS receiver, 41—Working device, 42—Machine body, 51—Construction management system, 61—Processing device, 62—Storage device, 10 0, 200, 300, 400—Controller; 101—Positioning Calculation Unit; 102—Target Setting Unit; 103—Motion Control Unit; 104—Display Control Unit; 111—Status Calculation Unit; 121, 221, 321—Target Data Calculation Unit; 122, 222—Constraint Setting Unit; 131, 231—Exit Judgment Unit; 132, 232, 432—Predictive Control Unit; 133—Actuator Control Unit; 134, 234, 334, 434—Calculation Condition Change Unit; 141, 241, 441—Attention Arousal Unit; A1—Motion Limitation Area; A1′—Temporary Motion Limitation Area; A2—Intrusion Prevention Area; POP1—Exit Notification Image; POP2—Intention Confirmation Image; POP3—Selection Image; Se—Target Excavation Surface (Boundary Surface between Motion Limitation Area and Intrusion Prevention Area); Sp—Intrusion Prevention Surface (Boundary Surface between Motion Limitation Area and Intrusion Prevention Area).

Claims

1. A type of operating machinery, comprising: A working device comprising: a plurality of driven components including a working tool; and a plurality of hydraulic actuators for driving the plurality of driven components; The machine body, on which the aforementioned working device is installed; A posture detection device that detects the posture of the working device; A position detection device that detects the position of the machine body; and The controller controls the operation of the working device. The controller performs the following model predictive control: Based on the posture of the working device detected by the posture detection device and the position of the machine body detected by the position detection device, the coordinates of the working tool at the current time point are calculated. Based on the coordinates of the working tool and the boundary between the action-limited area allowing the working device to move and the intrusion-prevention area preventing the working device from intruding, constraints are set in the model predictive control to prevent the working device from intruding into the intrusion-prevention area. The target operating speed of the hydraulic actuator is calculated for a predetermined period of time from the current time point in a manner that satisfies the constraints and minimizes the deviation between the coordinates of the working tool and the target coordinates of the working tool. The characteristics of this operating machine are: The controller performs the following action to disable control: Based on the posture of the working device detected by the posture detection device, the operating speed of the hydraulic actuator is calculated. The hydraulic actuator is controlled in such a way that its operating speed matches the target operating speed. Determine whether the position of the control point of the working device has deviated from the constraint condition. If the boundary surface is set such that the coordinates of the working tool are located in the intrusion prevention area, or if the position of the control point of the working device is determined to be out of the constraint condition due to a decrease in the detection accuracy of the position detection device, the operation of the working device shall be prohibited or stopped.

2. The operating machinery according to claim 1, characterized in that, If the controller determines that the position of the control point of the working device has deviated from the constraint conditions, the controller executes the action to prohibit control. In the action prohibition control, the controller sets the target action speed of the hydraulic actuator to 0.

3. The operating machinery according to claim 1, characterized in that, If the controller determines that the position of the control point of the working device has deviated from the constraint conditions, the controller executes the action to prohibit control. In the action prohibition control, the controller sets the coordinates of the working tool at the target coordinates of the working tool at the current time point and invalidates the constraint conditions.

4. The work machine of claim 1, wherein, have: Input device, which is operated by an operator; and The notification device notifies the operator of information. If the controller determines that the position of the control point of the working device has deviated from the constraint condition, the controller will execute output control to output the determination result to the notification device. In the output control, the controller, through the notification device, notifies the operator of information indicating that the position of the control point of the working device has deviated from the constraints and confirms the intention to activate the working device. If the controller determines that the position of the control point of the working device has deviated from the constraint conditions, and upon inputting an operation signal indicating that the operator intends to move the working device, the controller invalidates the constraint conditions and sets the target coordinates of the working tool so that the control point of the working device approaches the action-limited area. If the controller determines that the position of the control point of the working device has deviated from the constraint conditions, and an operation signal indicating that the operator does not intend to make the working device move is input, the controller executes the action prohibition control.

5. The operating machinery according to claim 1, characterized in that, have: Input device, which is operated by an operator; and The notification device notifies the operator of information. If the controller determines that the position of the control point of the working device has deviated from the constraint conditions, it executes output control to output the determination result to the notification device and the action prohibition control. In the output control, the controller, through the notification device, notifies the operator of information indicating that the position of the control point of the working device has deviated from the constraints and confirms the intention to activate the working device. If the controller determines that the position of the control point of the working device is out of the constraint condition, and an operation signal indicating that the operator intends to make the working device move is input, the controller releases the action prohibition control, invalidates the constraint condition, and sets the target coordinates of the working tool in such a way that the control point of the working device is close to the action limitation area.

6. The operating machinery according to claim 1, characterized in that, The position detection device receives signals from GNSS satellites to detect the position of the aircraft. If the controller determines that the position of the control point of the working device has deviated from the constraint conditions, the controller executes the action to prohibit control. The controller determines whether the detection accuracy of the position detection device is good based on the signal from the position detection device. If it is determined that the position detection device has poor detection accuracy, the operation will be prohibited from continuing. If the position detection device is determined to have good detection accuracy, the action prohibition control is lifted.

7. The operating machinery according to claim 1, characterized in that, have: Input device, which is operated by an operator; and The notification device notifies the operator of information. The position detection device receives signals from GNSS satellites to detect the position of the aircraft. The controller determines whether the detection accuracy of the position detection device is good based on the signal from the position detection device. If the position detection device is determined to have poor detection accuracy, the action prohibition control and notification control will be executed regardless of whether the position of the control point of the working device deviates from the constraint conditions. In the notification control, the notification device notifies the operator of information indicating poor detection accuracy of the position detection device and confirms the intention to activate the operating device. If the position detection device is determined to have poor detection accuracy, and an operation signal indicating that the operator intends to activate the working device is input, the action prohibition control is released, and the constraint condition is invalidated.

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