Construction machine

Abstract

The purpose of the present invention is to provide a construction machine equipped with an operation assistance function that can prevent work from being continued in a state in which control of a work tool is unstable, even if it is predicted that the work tool may move outside its movable range due to an operation of an operator. This construction machine comprises: an actuator that drives a vehicle body and a work device that includes a work tool; and a controller that calculates a target trajectory of the work tool on the basis of design surface information, orientation information of the work device and the vehicle body, and operation information for the actuator, and controls the operation of the actuator such that the work tool follows the target trajectory. The controller determines, on the basis of mechanical constraints of the work device and the vehicle body, whether a target position and orientation included in the target trajectory can be achieved, and generates and outputs determination information including the type of actuator that is outside the movable range at a target position and orientation determined to be infeasible.

Description

Construction Machinery

[0001] The present invention relates to a construction machine such as a hydraulic excavator that controls the operation of an actuator so that a work tool follows a target trajectory.

[0002] Against the background of a decrease in the number of skilled operators, construction machines are expected to be equipped with operation support functions mainly for unskilled operators, or automatic control functions or semi-automatic control functions for labor saving. In addition, construction machines such as hydraulic excavators equipped with tilt rotators have begun to spread mainly in Europe, and it is necessary to develop advanced operation support functions with more degrees of freedom.

[0003] The bucket attached to the arm via the tilt rotator can change the angle of the bucket relative to the arm in directions other than the crowding direction and the dumping direction, so that excavation work and shaping work can be performed over a wide range without traveling by means of the lower traveling body. For the bucket attached to the arm via the tilt rotator, in addition to the lever operation for operating the bucket directly attached to the arm in the crowding direction and the dumping direction, it is necessary to operate actuators (a tilt cylinder and a rotary motor) that change the angle of the bucket in the tilt direction and the rotary direction. Therefore, the bucket attached to the arm via the tilt rotator has a higher operation difficulty than the bucket directly attached to the arm, so a more advanced operation support function is required.

[0004] As a prior art related to an operation support function for a bucket attached to an arm via a tilt rotator, Patent Document 1 is known. Patent Document 1 discloses a control system for a construction machine that rotates a rotating body at a limited rotation speed so as to prevent the bucket from digging into a design surface when it is predicted that the tilt speed of the bucket will exceed the maximum speed in the future according to an operator's operation.

[0005] Japanese Unexamined Patent Publication No. 2023-026481

[0006] The technology disclosed in Patent Document 1 only considers the constraints on the operating speed of the bucket, and does not consider any mechanical constraints in the work device and slewing body. Therefore, the technology disclosed in Patent Document 1 has difficulty adequately addressing situations where the work tool is expected to move outside its range of motion due to mechanical constraints in the work device and slewing body, and the control of the bucket by the operation support function becomes unstable. As a result, the technology disclosed in Patent Document 1 may have reduced work accuracy near the boundary of the work tool's range of motion.

[0007] The present invention has been made in view of the above, and aims to provide a construction machine equipped with an operation support function that can prevent work from continuing in an unstable state of control of the work tool, even when it is expected that the work tool will move outside its range of motion due to the operator's actions.

[0008] To solve the above problems, the present invention provides a construction machine comprising: a multi-jointed work device rotatably connected to a vehicle body and including a work tool connected to a tilt rotator; a posture detection device for detecting posture information of the work device and the vehicle body; an actuator for driving the work device and the vehicle body; an operation detection device for detecting operator operation information for the actuator; and a controller that calculates a target trajectory, which is time-series data of the future target position and posture of the work tool, based on design surface information indicating the target shape of the work object, the posture information and the operation information, and controls the operation of the actuator so that the work tool follows the target trajectory, wherein the controller determines whether the target position and posture included in the target trajectory is achievable based on the mechanical constraints of the work device and the vehicle body, generates determination information including the type of actuator that is outside the range of motion in the target position and posture determined to be unachievable, and outputs the generated determination information.

[0009] According to the present invention, even in cases where it is anticipated that the work tool may move outside its range of motion due to operator operation, it is possible to provide a construction machine equipped with an operation support function that can prevent work from continuing in a state of unstable control of the work tool. Other problems, components, and effects will be clarified by the following description of embodiments.

[0010] A schematic side view showing the configuration of a hydraulic excavator, an example of construction machinery. A block diagram illustrating the functions of the controller of the first embodiment. A diagram illustrating the target trajectory calculated by the target trajectory calculation unit shown in Figure 2. A flowchart showing the processing contents of the controller shown in Figure 2. A flowchart showing the processing contents of the feasibility determination unit shown in Figure 2. A flowchart showing the processing contents of the target motion calculation unit shown in Figure 2. A diagram illustrating the predicted trajectory calculated in step S304 of Figure 6. A diagram illustrating the trajectory and work accuracy of the bucket controlled by the controller of the comparative example. A diagram illustrating the trajectory and work accuracy of the bucket controlled by the controller of the first embodiment. A flowchart showing the processing contents of the feasibility determination unit of the second embodiment. A diagram illustrating the trajectory and work accuracy of the bucket controlled by the controller of the second embodiment. A block diagram illustrating the functions of the controller of the third embodiment. A diagram showing the posture condition table. A flowchart showing the processing contents of the controller shown in Figure 12. A diagram illustrating the trajectory and work accuracy of the bucket controlled by the controller of the third embodiment.

[0011] Embodiments of the present invention will be described below with reference to the drawings. In each embodiment, components denoted by the same reference numerals are similar in each embodiment unless otherwise specified, and their descriptions will be omitted.

[0012] In this embodiment, the construction machine 30 is described using a hydraulic excavator equipped with a bucket 1c as a work tool (attachment) at the tip of the work device 1 as an example. The construction machine 30 may be a hydraulic excavator equipped with work tools other than the bucket 1c, or it may be a construction machine other than a hydraulic excavator.

[0013] [First Embodiment] A first embodiment of the present invention will be described with reference to Figures 1 to 9. Figure 1 is a schematic side view showing the configuration of a hydraulic excavator, which is an example of a construction machine 30.

[0014] The construction machine 30 comprises a multi-jointed working device 1 formed by connecting a plurality of components 1a to 1d, and an upper slewing body 2 and a lower traveling body 3 that constitute the vehicle body 2 and 3. The lower traveling body 3 is driven by a traveling motor (not shown). The upper slewing body 2 is rotatably attached to the lower traveling body 3 via a slewing device (not shown).

[0015] The upper rotating body 2 is driven by the rotating motor 8c of the rotating device and rotates in the yaw direction (direction around the Z axis) of the vehicle coordinate system FV set on the vehicle bodies 2 and 3. The rotation angle of the upper rotating body 2 relative to the lower traveling body 3 is detected by a rotation angle detection device 4c attached to the rotating device. The upper rotating body 2 is also equipped with a vehicle body angle detection device 5 that detects the inclination angle of the vehicle bodies 2 and 3 with respect to the horizontal plane, and a GNSS receiving device 6 (including a GNSS antenna and receiver) that detects the position information of the vehicle bodies 2 and 3. Furthermore, the upper rotating body 2 is equipped with a driver's cab 7 in which the operator sits, and a controller 10 that controls the overall operation of the construction machine 30.

[0016] The operator's cab 7 is equipped with an operating device for the operator to operate the actuator 8, and an operation detection device 7a that detects the amount and direction of operation of the operating device by the operator (hereinafter also referred to as "operation information") (see Figure 2). In other words, the operation detection device 7a detects the operator's operation information for the actuator 8. The larger the amount of operation of the operating device included in the operation information detected by the operation detection device 7a, the faster the movement speed or rotation speed of the bucket 1c becomes, and the faster the operating speed required of the corresponding actuator 8 becomes. The direction of operation of the operating device included in the operation information detected by the operation detection device 7a corresponds to the movement direction or rotation direction of the bucket 1c and corresponds to the operating direction required of the corresponding actuator 8.

[0017] Furthermore, the operator's cab 7 is equipped with a display device 7d that displays various information, including warnings to the operator, a posture condition setting device 7b that sets the posture conditions of the bucket 1c (described later), and a design surface setting device 7c that sets the design surface information (described later). The display device 7d is configured as a touchscreen monitor. The posture condition setting device 7b and the design surface setting device 7c may be provided integrally with the display device 7d, or they may be configured as external terminals such as tablet PCs. The posture condition setting device 7b and the design surface setting device 7c receive input operations from the operator and set the posture conditions of the bucket 1c and the design surface information corresponding to the input operations in the controller 10.

[0018] As shown in Figure 1, the work device 1 includes a boom 1a rotatably connected to the front of the upper slewing body 2, an arm 1b rotatably connected to the tip of the boom 1a, a tilt rotator 1d connected to the tip of the arm 1b, and a bucket 1c rotatably connected to the arm 1b via the tilt rotator 1d. In other words, the work device 1 is a multi-jointed work device that includes a bucket 1c, which is a work tool connected to the tilt rotator 1d, and is rotatably connected to the vehicle bodies 2 and 3.

[0019] The boom 1a and arm 1b are driven by boom cylinder 8a and arm cylinder 8b, and rotate in the pitch direction (direction around the Y axis) of the vehicle coordinate system FV. The rotation angle of the boom 1a relative to the upper slewing body 2 (hereinafter also referred to as the "boom angle") is detected by a boom angle detection device 4a attached to the boom 1a. The rotation angle of the arm 1b relative to the boom 1a (hereinafter also referred to as the "arm angle") is detected by an arm angle detection device 4b attached to the arm 1b.

[0020] Bucket 1c is a work tool used for excavation or shaping work on construction targets such as slopes or horizontal surfaces in mines. Bucket 1c is connected to a tilt rotator 1d and rotates around each coordinate axis of the work tool coordinate system FE set at the base end of bucket 1c. Bucket 1c is driven by a bucket cylinder 8d and rotates in the pitch direction (direction around the y-axis) of the work tool coordinate system FE. The rotation angle of bucket 1c in the pitch direction relative to arm 1b (hereinafter also referred to as "bucket angle") is detected by a bucket tilt angle detection device 4d attached to the tilt rotator 1d. Bucket 1c is driven by a tilt cylinder 8e and rotates in the roll direction (direction around the x-axis) of the work tool coordinate system FE. The rotation angle of bucket 1c in the roll direction relative to arm 1b (hereinafter also referred to as "tilt angle") is detected by a bucket tilt angle detection device 4d. The bucket 1c is driven by a rotary motor 8f and rotates in the yaw direction (direction around the z-axis) of the work tool coordinate system FE. The rotation angle of the bucket 1c in the yaw direction relative to the arm 1b (hereinafter also referred to as the "rotary angle") is detected by a rotary angle detection device 4e attached to the tilt rotator 1d.

[0021] The vehicle coordinate system FV has its origin at the intersection of the pivot axis of the upper rotating body 2 and the ground contact surface of the lower traveling body 3. The vehicle coordinate system FV is an orthogonal coordinate system having a Z-axis along the pivot axis, an X-axis along the front-rear direction of the lower traveling body 3 perpendicular to the Z-axis, and a Y-axis along the left-right direction of the lower traveling body 3 perpendicular to the Z-axis and X-axis. The work tool coordinate system FE has its origin at the intersection of the pivot axis of the bucket 1c by the rotary motor 8f and a straight line along the bucket pin that constitutes the pivot point of the bucket 1c by the bucket cylinder 8d. The work tool coordinate system FE is an orthogonal coordinate system having a z-axis along the pivot axis of the bucket 1c by the rotary motor 8f, a y-axis along the bucket pin perpendicular to the z-axis, and an x-axis in a direction perpendicular to the z-axis and y-axis.

[0022] In this embodiment, the boom cylinder 8a, arm cylinder 8b, slewing motor 8c, bucket cylinder 8d, tilt cylinder 8e, and rotary motor 8f are collectively referred to as the "actuator 8". That is, the actuator 8 is an actuator that drives the work device 1 and the upper slewing body 2, which change the position and orientation of the bucket 1c, which is a work tool. The actuator 8 is operated by hydraulic fluid supplied from a hydraulic pump driven by a prime mover such as an engine or electric motor. The operation of the actuator 8 is controlled by controlling the flow rate and direction of the hydraulic fluid supplied from the hydraulic pump using a control valve. The operation of the control valve is controlled by the controller 10 based on operation information detected by the operation detection device 7a. In this way, the operation of the actuator 8 is controlled.

[0023] In this embodiment, the boom angle detection device 4a, arm angle detection device 4b, slewing angle detection device 4c, bucket tilt angle detection device 4d, and rotary angle detection device 4e are collectively referred to as the "attitude detection device 4". The attitude detection device 4 may also include the vehicle body angle detection device 5. In this embodiment, the joint angles of the work device 1, consisting of the boom angle, arm angle, bucket angle, tilt angle, and rotary angle, as well as the slewing angle of the upper slewing body 2, are collectively referred to as the "attitude information" detected by the attitude detection device 4. The attitude information may also include the inclination angles of the vehicle bodies 2 and 3. The attitude detection device 4 is composed of various sensors such as inertial measuring devices or potentiometers.

[0024] Figure 2 is a block diagram illustrating the functions of the controller 10 in the first embodiment. Figure 3 is a diagram illustrating the target trajectory calculated by the target trajectory calculation unit 10c shown in Figure 2.

[0025] The controller 10 is a control device equipped with a machine control operation support function that semi-automatically controls the actuator 8 based on the operator's input. Specifically, the controller 10 calculates the target trajectory of the bucket 1c, which is a work tool, based on design surface information indicating the target shape of the work object, posture information detected by the posture detection device 4, and operation information detected by the operation detection device 7a. The controller 10 then controls the operation of the actuator 8 so that the bucket 1c follows the target trajectory.

[0026] The controller 10 is composed of a processor such as a CPU, memory such as ROM and RAM, and a program that implements various functions of the controller 10. The controller 10 realizes its various functions by having the processor execute the program stored in memory. As for these various functions, the controller 10 includes a position and attitude calculation unit 10a, a coordinate transformation unit 10b, a target trajectory calculation unit 10c, a feasibility determination unit 10d, an alarm control unit 10e, and an actuator control unit 10g.

[0027] The position and orientation calculation unit 10a calculates the three-dimensional position and three-dimensional orientation (hereinafter also referred to as "position and orientation") of the bucket 1c, which is a work tool, based on the orientation information of the work device 1 and the vehicle body 2, 3 detected by the orientation detection device 4. The position and orientation calculation unit 10a calculates the position and orientation of the bucket 1c with respect to the vehicle body coordinate system FV.

[0028] The coordinate transformation unit 10b acquires the position and orientation of vehicle bodies 2 and 3 detected by the GNSS receiver 6 and the vehicle body angle detection device 5. The position and orientation of vehicle bodies 2 and 3 detected by the GNSS receiver 6 and the vehicle body angle detection device 5 is data based on the global coordinate system of the construction site. The coordinate transformation unit 10b converts the position and orientation of vehicle bodies 2 and 3 based on the global coordinate system to the position and orientation of vehicle bodies 2 and 3 based on the vehicle body coordinate system FV. The coordinate transformation unit 10b also acquires information on the design surface that indicates the target shape of the construction target, which is set in the controller 10 by the design surface setting device 7c. The design surface information is coordinate data of the design surface based on the global coordinate system. Based on the position and orientation of vehicle bodies 2 and 3 based on the vehicle body coordinate system FV, the coordinate transformation unit 10b converts the design surface information based on the global coordinate system to the design surface information based on the vehicle body coordinate system FV.

[0029] The target trajectory calculation unit 10c calculates the target trajectory of bucket 1c based on the operation information detected by the operation detection device 7a and the attitude conditions of bucket 1c set in the controller 10 by the attitude condition setting device 7b. The target trajectory is time-series data of the future target position and target attitude of bucket 1c (hereinafter also referred to as "target position and attitude"). The attitude conditions of bucket 1c are conditions that constrain the attitude of bucket 1c with respect to the design plane when bucket 1c moves following the target trajectory. The attitude conditions of bucket 1c are set by the attitude condition setting device 7b to be one of a plurality of predetermined attitude conditions, as shown in Figure 13 described later.

[0030] The target trajectory calculation unit 10c calculates multiple target position and attitudes at regular intervals such that the bucket 1c satisfies the attitude conditions set by the attitude condition setting device 7b and the bucket 1c moves according to the operation information detected by the operation detection device 7a. In this way, the target trajectory calculation unit 10c calculates the target trajectory of the bucket 1c. The target trajectory calculation unit 10c calculates a number of target position and attitudes corresponding to a preset predicted length (predicted horizon) at predetermined control cycles.

[0031] The upper part of Figure 3 shows the target trajectory in which bucket 1c moves from its current position and orientation CP to the leftward direction of the paper, while keeping the bottom surface of bucket 1c in surface contact with the design surface S. The target trajectory shown in the upper part of Figure 3 includes multiple target position and orientation values ​​TP1 to TP3. Target position and orientation values ​​TP1 to TP3 are calculated based on the vehicle coordinate system FV. The lower part of Figure 3 shows that each target position and orientation included in the target trajectory consists of a target position and target orientation, and that a number of calculations corresponding to the predicted length are performed at regular time intervals.

[0032] The target position that constitutes each target position and attitude is calculated assuming that each actuator 8 operates at a constant speed relative to the required operating speed of the actuator 8, which is determined according to the amount of operation included in the operation information detected by the operation detection device 7a. The target attitude that constitutes each target position and attitude is calculated to satisfy the attitude conditions of the bucket 1c set by the attitude condition setting device 7b. A specific example of the attitude conditions is shown in Figure 13 (the attitude conditions of the bucket 1c set in the example of Figure 3 correspond to PC4 in Figure 13). The target trajectory is composed of a sequence of points of target position and attitude calculated a number of times corresponding to the predicted length with a constant time step width, i.e., time-series data of target position and attitude.

[0033] The feasibility determination unit 10d determines whether the target trajectory of the bucket 1c calculated by the target trajectory calculation unit 10c is feasible. Specifically, the feasibility determination unit 10d determines whether each target position and orientation included in the target trajectory of the bucket 1c is feasible based on the mechanical constraints of the work device 1 and the vehicle bodies 2 and 3 (hereinafter also referred to as "mechanical constraints"). The mechanical constraints of the work device 1 and the vehicle bodies 2 and 3 refer to constraints on the range of motion of each joint of the work device 1 and the upper rotating body 2. For example, this refers to a state where the tilt cylinder 8e or bucket cylinder 8d, etc., have reached their stroke end, and the orientation of the bucket 1c cannot be changed any further, making it impossible to achieve the target orientation.

[0034] If the feasibility determination unit 10d determines that at least one target position and orientation included in the target trajectory of the bucket 1c calculated by the target trajectory calculation unit 10c is unrealizable, it identifies the type of actuator 8 that is outside the range of motion for the target position and orientation of the bucket 1c that is determined to be unrealizable. The feasibility determination unit 10d then generates determination information including the identified type of actuator 8 and outputs the generated determination information.

[0035] Based on the determination information generated by the feasibility determination unit 10d, the alarm control unit 10e causes the display device 7d to display an alarm that includes the type of actuator 8 that is outside the movable range at the target position and orientation of the bucket 1c, which has been determined to be unrealizable.

[0036] The target motion calculation unit 10f calculates the target operating speed of the actuator 8 so that the bucket 1c moves in accordance with the target trajectory of the bucket 1c calculated by the target trajectory calculation unit 10c. That is, the target motion calculation unit 10f calculates the target operating speed of the actuator 8 for each target position and attitude so as to realize each target position and attitude included in the target trajectory of the bucket 1c calculated by the target trajectory calculation unit 10c. The target motion calculation unit 10f may also calculate the target operating speed of the actuator 8 using model predictive control.

[0037] The actuator control unit 10g calculates a control command to the actuator 8 to achieve the target operating speed of the actuator 8 calculated by the target motion calculation unit 10f. The actuator control unit 10g then controls the operation of the actuator 8 by operating the control valve connected to the actuator 8 according to the calculated control command.

[0038] Figure 4 is a flowchart showing the processing details of the controller 10 shown in Figure 2.

[0039] In step S101, the position and orientation calculation unit 10a calculates the current position and orientation of the bucket 1c, which is a work tool.

[0040] In step S102, the coordinate conversion unit 10b acquires design surface information set by the design surface setting device 7c, and converts the information into design surface information based on the vehicle body coordinate system FV.

[0041] In step S103, the target trajectory calculation unit 10c calculates the target trajectory of the bucket 1c by calculating a number of future target positions and postures of the bucket 1c corresponding to the predicted length at fixed time intervals.

[0042] In step S104, the feasibility determination unit 10d determines whether each target position and posture included in the target trajectory calculated in step S103 is feasible.

[0043] In step S105, the feasibility determination unit 10d determines whether all target positions and postures included in the target trajectory are determined to be feasible. If it is determined that all target positions and postures included in the target trajectory are feasible, the feasibility determination unit 10d proceeds to step S108. If it is determined that at least one target position and posture included in the target trajectory is not feasible, the feasibility determination unit 10d identifies the type of target actuator 8 that is outside the movable range in the unfeasible target position and posture. Then, the feasibility determination unit 10d generates determination information including the identified type of the actuator 8, and proceeds to step S106.

[0044] In step S106, based on the determination information, the feasibility determination unit 10d corrects the target trajectory calculated in step S103 such that the unfeasible target position and posture of the bucket 1c matches the target position and posture determined to be feasible at the previous time. This eliminates the difference in the operation of the actuator 8 between the unfeasible target position and posture and the immediately preceding feasible target position and posture. As a result, when the position and posture of the bucket 1c reaches the unfeasible target position and posture, the feasibility determination unit 10d can stop only the operation of the target actuator 8 that is outside the movable range in the unfeasible target position and posture, and can continue the operation of the actuator 8 other than the actuator 8 whose operation is stopped.

[0045] In step S107, the alarm control unit 10e causes the display device 7d to display an alarm including the type of the target actuator 8 that is out of the movable range at the target position and orientation of the bucket 1c determined to be unrealizable, based on the determination information.

[0046] In step S108, the target motion calculation unit 10f calculates the target motion speed of the actuator 8 so as to realize each target position and orientation included in the target trajectory calculated in step S103 or each target position and orientation included in the target trajectory corrected in step S106.

[0047] In step S109, the actuator control unit 10g calculates a control command for the actuator 8 so as to achieve the target motion speed of the actuator 8 calculated in step S108, and controls the motion of the actuator 8. Thereafter, the controller 10 ends the processing shown in the flowchart of FIG. 4.

[0048] FIG. 5 is a flowchart showing the processing content of the realizability determination unit 10d shown in FIG. 2. FIG. 5 is a flowchart illustrating steps S104 to S106 of FIG. 4 in detail.

[0049] In step S201, the realizability determination unit 10d selects a target position and orientation at a certain time included in the target trajectory of the bucket 1c calculated in step S103.

[0050] In step S202, the realizability determination unit 10d calculates, by inverse kinematics, the target joint angles of the work device 1 and the target swing angle of the upper swing structure 2 required for the bucket 1c to achieve the target position and orientation selected in step S201.

[0051] In step S203, the realizability determination unit 10d determines whether the target joint angles of the work device 1 and the target swing angle of the upper swing structure 2 (hereinafter also referred to as "target joint angles, etc.") could be calculated by inverse kinematics (whether a solution was obtained). If calculation by inverse kinematics was possible, the realizability determination unit 10d proceeds to step S205. If calculation by inverse kinematics was not possible, the realizability determination unit 10d proceeds to step S204.

[0052] In step S204, the feasibility determination unit 10d compares the inverse kinematics calculation result, which was determined to be uncalculable in step S203, with the inverse kinematics calculation result, which was determined to be calculable in the previous time step, to identify the target joint angle, etc., of the factors that were determined to be uncalcululable. After that, the feasibility determination unit 10d proceeds to step S208.

[0053] In step S205, the feasibility determination unit 10d determines whether all target joint angles calculated by inverse kinematics are within the range of motion of the work device 1 and the upper swivel body 2. If all target joint angles are within the range of motion, the feasibility determination unit 10d proceeds to step S206. If at least one target joint angle is outside the range of motion, the feasibility determination unit 10d proceeds to step S208. Step S205 is a process in which the feasibility determination unit 10d determines whether the target position and posture can be achieved based on the mechanical constraints of the work device 1 and the upper swivel body 2.

[0054] In step S206, the feasibility determination unit 10d determines whether the change in all target joint angles, etc., calculated by inverse kinematics from the previous time is less than or equal to a threshold. This threshold is set in advance by the constraints on the operating speeds of the work device 1 and the upper rotating body 2, which are determined based on the constraints on the operating speed of the actuator 8. If the change in all target joint angles, etc., is less than or equal to the threshold, the feasibility determination unit 10d proceeds to step S207. If the change in at least one target joint angle, etc., is greater than the threshold, the feasibility determination unit 10d proceeds to step S208.

[0055] In step S207, the feasibility determination unit 10d determines that the target position and attitude selected in step S201 is feasible. Subsequently, the feasibility determination unit 10d proceeds to step S210.

[0056] In step S208, the feasibility determination unit 10d determines that the target position and posture selected in step S201 is unattainable. The feasibility determination unit 10d then identifies the type of actuator 8 corresponding to the target joint angle, etc. The feasibility determination unit 10d determines that the identified type of actuator 8 is an actuator that is outside the range of motion in the target position and posture that was determined to be unattainable. The feasibility determination unit 10d generates determination information including the type of actuator 8 that is outside the range of motion in the target position and posture that was determined to be unattainable. The target joint angle, etc. refers to the target joint angle, etc. identified in step S204, the target joint angle, etc. determined to be outside the range of motion in step S205, or the target joint angle, etc. whose change amount was determined to be greater than a threshold in step S206.

[0057] In step S209, the feasibility determination unit 10d corrects the target position and orientation selected in step S201 so that the corresponding target joint angle, etc. matches the appropriate target joint angle, etc. value from the previous time. As a result, when the position and orientation of the bucket 1c reaches a target position and orientation that has been determined to be unattainable, the feasibility determination unit 10d can stop the operation of only the target actuator 8 that is outside the range of motion at the target position and orientation that has been determined to be unattainable, and can continue the operation of other actuators 8 that have not had their operation stopped. The appropriate target joint angle, etc. from the previous time refers to the target joint angle, etc. that was determined to be calculable by inverse kinematics at the previous time, the target joint angle, etc. that was determined to be within the range of motion at the previous time, or the target joint angle, etc. that was determined to have a change amount below a threshold at the previous time.

[0058] In step S210, the feasibility determination unit 10d determines whether or not all target positions and orientations included in the target trajectory have been selected. If not all target positions and orientations have been selected, the feasibility determination unit 10d proceeds to step S201. If all target positions and orientations have been selected, the feasibility determination unit 10d outputs the determination information and terminates the process shown in the flowchart of Figure 5.

[0059] Figure 6 is a flowchart showing the processing details of the target motion calculation unit 10f shown in Figure 2. Figure 6 is a flowchart showing step S108 in Figure 4 in detail. Figure 7 is a diagram illustrating the predicted trajectory calculated in step S304 of Figure 6.

[0060] In step S301, the target motion calculation unit 10f acquires the target trajectory of bucket 1c calculated in step S103, or the target trajectory of bucket 1c corrected in step S106.

[0061] In step S302, the target motion calculation unit 10f acquires the current position and orientation of the bucket 1c calculated in step S101.

[0062] In step S303, the target motion calculation unit 10f initializes the candidate target operating speed of the actuator 8 calculated in the previous time step. The initialized candidate target operating speed of the actuator 8 is a value determined based on the required operating speed of the actuator 8 corresponding to the operation amount included in the operation information detected by the operation detection device 7a.

[0063] In step S304, the target motion calculation unit 10f calculates the predicted trajectory of bucket 1c based on the current position and orientation of bucket 1c and candidate target operating speeds of actuator 8. The predicted trajectory of bucket 1c is time-series data of the predicted position and orientation of bucket 1c (hereinafter also referred to as "predicted position and orientation") based on the current position and orientation of bucket 1c and candidate target operating speeds of actuator 8. As shown in Figure 7, the predicted trajectory is composed of a sequence of points of predicted position and orientation calculated a number of times corresponding to the predicted length with a fixed time step width.

[0064] In step S305, the target motion calculation unit 10f determines whether the predicted position and attitude included in the predicted trajectory calculated in step S304 matches the target position and attitude included in the target trajectory acquired in step S301. If all predicted position and attitudes match the target position and attitude, the target motion calculation unit 10f proceeds to step S307. If at least one predicted position and attitude does not match the target position and attitude, the target motion calculation unit 10f proceeds to step S306.

[0065] In step S306, the target motion calculation unit 10f corrects the candidate target motion speed of the actuator 8 so that the predicted position and attitude, which was determined not to match the target position and attitude in step S305, matches the target position and attitude. After that, the target motion calculation unit 10f proceeds to step S304.

[0066] In step S307, the target motion calculation unit 10f determines the candidate target operating speed of the actuator 8 as the optimal target operating speed of the actuator 8 and outputs it. After that, the target motion calculation unit 10f completes the process shown in the flowchart of Figure 6.

[0067] In the flowchart of Figure 6, model predictive control is used to calculate the target operating speed of actuator 8 so that the predicted trajectory of bucket 1c matches the target trajectory. In other words, steps S304 to S306 describe the outline of the convergence calculation of the optimization problem performed by model predictive control. If the predicted trajectory calculated in step S304 based on the corrected target operating speed candidate in step S306 matches the target trajectory, the target motion calculation unit 10f terminates the convergence calculation and outputs the current target operating speed candidate for actuator 8 as the optimal target operating speed to the actuator control unit 10g in step S307. However, the target motion calculation unit 10f may calculate the target operating speed of actuator 8 using a method other than model predictive control.

[0068] Figure 8 illustrates the trajectory and work accuracy of the bucket 1c controlled by the controller 10 of the comparative example. Figure 9 illustrates the trajectory and work accuracy of the bucket 1c controlled by the controller 10 of the first embodiment.

[0069] The upper part of Figures 8 and 9 shows an example of semi-automatic control during shaping work in which the controller 10 moves the bucket 1c from position P1 to P5 while ensuring that the bottom surface of the bucket 1c is in surface contact with the design surface S. The lower part of Figures 8 and 9 shows examples of shaping errors of the bucket 1c (shape errors relative to the design surface S of the shaped construction object) at each position and position P1 to P5. In Figures 8 and 9, it is assumed that the target position and position that the bucket 1c can achieve is calculated for position and position P1 to P3, and that the target position and position that the bucket 1c cannot achieve is calculated for position and position P4.

[0070] In the comparative example controller 10, as shown in Figure 8, the target position and orientation that the bucket 1c can achieve is calculated for position and orientation P1 to P3, so the bucket 1c works in an appropriate position and orientation that follows the target position and orientation. As a result, the shaping error of the bucket 1c is small in position and orientation P1 to P3, and the bucket 1c can work with high precision. However, in position and orientation P4, an unattainable target position and orientation is calculated, so the bucket 1c tries to forcibly achieve the unattainable target position and orientation. As a result, the shaping error of the bucket 1c becomes excessively large in position and orientation P4, and the work accuracy of the bucket 1c decreases excessively. Furthermore, the operator does not realize that the bucket 1c cannot work in an appropriate position and orientation, that is, that the bucket 1c is outside the range of motion, and tries to move the bucket 1c to position and orientation P5. As a result, the shaping error of the bucket 1c becomes even larger in position and orientation P5, and the work accuracy of the bucket 1c decreases even further.

[0071] In the controller 10 of the first embodiment, as shown in Figure 9, the target position and orientation that the bucket 1c can achieve is calculated for position and orientation P1 to P3. Therefore, similar to the comparative example shown in Figure 8, the shaping error of the bucket 1c is small, and the bucket 1c can work with high precision. On the other hand, at position and orientation P4, a target position and orientation that the bucket 1c cannot achieve is calculated. When the position and orientation of the bucket 1c reaches P4, the controller 10 of the first embodiment stops the operation of only the actuator 8 that is outside the movable range. As a result, at position and orientation P4, the shaping error of the bucket 1c does not become excessively large, and the work accuracy of the bucket 1c does not decrease excessively. Furthermore, since an alarm is displayed on the display device 7d, the operator can notice that the bucket 1c cannot work at the proper position and orientation, that is, that the bucket 1c is outside the movable range, and can temporarily stop the operation at position and orientation P4. As a result, at position and orientation P5, it is possible to prevent the shaping error of the bucket 1c from becoming even larger and to prevent a further decrease in the work accuracy of the bucket 1c.

[0072] Thus, in the construction machine 30 of the first embodiment, if it is predicted that the bucket 1c will move outside the movable range due to the operator's actions, the operation of only the actuator 8 that is outside the movable range can be stopped, and an alarm can be sent to the operator. As a result, the construction machine 30 of the first embodiment can reliably prevent the control of the actuator 8 by the operation support function from becoming unstable, and can reliably prevent a decrease in the working accuracy of the bucket 1c near the boundary of the movable range of the bucket 1c.

[0073] As described above, the construction machine 30 of the first embodiment is a construction machine comprising: a multi-jointed work device 1 that includes a bucket 1c, which is a work tool connected to a tilt rotator 1d, and is rotatably connected to the vehicle bodies 2 and 3; a posture detection device 4 that detects posture information of the work device 1 and the vehicle bodies 2 and 3; an actuator 8 that drives the work device 1 and the vehicle bodies 2 and 3; an operation detection device 7a that detects operator operation information for the actuator 8; and a controller 10 that calculates a target trajectory, which is time-series data of the future target position and posture of the bucket 1c, based on design surface information indicating the target shape of the construction target, posture information, and operation information, and controls the operation of the actuator 8 so that the bucket 1c follows the target trajectory. The controller 10 determines whether the target position and posture included in the target trajectory is achievable based on the mechanical constraints of the work device 1 and the vehicle bodies 2 and 3, generates determination information including the type of actuator 8 that is outside the range of motion in the target position and posture that is determined to be achievable, and outputs the generated determination information.

[0074] As a result, the construction machine 30 can identify the type of actuator 8 that is causing the bucket 1c to go out of its movable range due to the operator's operation. The construction machine 30 can also appropriately deal with situations where it is predicted that the bucket 1c will go out of its movable range due to the operator's operation, and can prevent the control of the actuator 8 by the operation support function from becoming unstable. Therefore, the construction machine 30 can prevent a decrease in the working accuracy of the bucket 1c near the boundary of the bucket 1c's movable range. Thus, according to the first embodiment, even in situations where it is predicted that the bucket 1c will go out of its movable range due to the operator's operation, it is possible to provide a construction machine 30 equipped with an operation support function that can prevent work from continuing in an unstable state of control of the bucket 1c.

[0075] Furthermore, the construction machine 30 of the first embodiment further includes a display device 7d that displays a warning to the operator. If the controller 10 determines that at least one target position or attitude included in the target trajectory is unattainable, it causes the display device 7d to display a warning based on the determination information, including the type of actuator that is outside the range of motion at the target position or attitude that was determined to be unattainable.

[0076] As a result, the construction machine 30 can make the operator aware of the type of actuator 8 that is causing the bucket 1c to go outside its range of motion due to the operator's actions. The construction machine 30 can prevent the control of the actuator 8 by the operation support function from becoming continuously unstable by having the operator continue to request the operation of the actuator 8 that is outside its range of motion. Therefore, the construction machine 30 can reliably prevent a decrease in the working accuracy of the bucket 1c near the boundary of the bucket 1c's range of motion. Thus, according to the first embodiment, even in cases where it is predicted that the bucket 1c will go outside its range of motion due to the operator's actions, it is possible to provide a construction machine 30 equipped with an operation support function that can reliably prevent work from continuing in a state of unstable control of the bucket 1c.

[0077] Furthermore, in the construction machine 30 of the first embodiment, if the controller 10 determines that at least one target position and attitude included in the target trajectory is unattainable, it stops the operation of only the actuator 8 that is outside the range of motion at the target position and attitude determined to be unattainable, based on the determination information.

[0078] As a result, the construction machine 30 can stop only the operation of the actuator 8 that causes the bucket 1c to go outside its movable range due to the operator's operation. The construction machine 30 can reliably prevent the control of the actuator 8 by the operation support function from becoming unstable, while preventing the actuator 8 from stopping excessively and reducing work efficiency. Therefore, the construction machine 30 can prevent a decrease in the work accuracy of the bucket 1c near the boundary of the bucket 1c's movable range, while preventing a decrease in the work efficiency of the bucket 1c. Thus, according to the first embodiment, even in cases where it is predicted that the bucket 1c will go outside its movable range due to the operator's operation, it is possible to provide a construction machine 30 equipped with an operation support function that can prevent work from continuing in an unstable state of control of the bucket 1c without reducing the work efficiency of the bucket 1c.

[0079] [Second Embodiment] A second embodiment of the present invention will be described with reference to Figures 10 and 11. In the second embodiment, the same components as in the first embodiment will not be described.

[0080] Figure 10 is a flowchart showing the processing content of the feasibility determination unit 10d in the second embodiment. Figure 10 is a flowchart corresponding to Figure 5. In Figure 10, step S209 in Figure 5 is replaced by step S212. Otherwise, the controller 10 in the second embodiment is the same as the controller 10 in the first embodiment.

[0081] In step S212, the feasibility determination unit 10d of the second embodiment corrects the target position and orientation selected in step S201 so that all target joint angles, etc., calculated by inverse kinematics match the appropriate target joint angle, etc., values ​​from the previous time. As a result, the feasibility determination unit 10d of the second embodiment can stop the operation of all actuators 8 after the bucket 1c has reached the final target position and orientation that has been determined to be feasible, but before the bucket 1c has reached a target position and orientation that has been determined to be unfeasible. Consequently, the controller 10 of the second embodiment can stop the operation of the bucket 1c from that point onward once the bucket 1c has reached the final target position and orientation that has been determined to be feasible.

[0082] Figure 11 illustrates the trajectory and work accuracy of the bucket 1c controlled by the controller 10 of the second embodiment.

[0083] The upper part of Figure 11 shows an example of semi-automatic control during shaping work, where the controller 10 moves the bucket 1c from position P1 to P5 while ensuring that the bottom surface of the bucket 1c is in surface contact with the design surface S, similar to Figure 9. The lower part of Figure 11 shows examples of shaping errors of the bucket 1c at each position and position P1 to P5, similar to Figure 9. In Figure 11, similar to Figure 9, it is assumed that the target position and position that the bucket 1c can achieve is calculated for positions and positions P1 to P3, and the target position and position that the bucket 1c cannot achieve is calculated for position and position P4.

[0084] In the controller 10 of the second embodiment, as shown in Figure 11, the target position and orientation that the bucket 1c can achieve is calculated for position and orientation P1 to P3. Therefore, similar to the first embodiment shown in Figure 9, the shaping error of the bucket 1c is small, and the bucket 1c can work with high precision. On the other hand, at position and orientation P4, a target position and orientation that the bucket 1c cannot achieve is calculated. The controller 10 of the second embodiment stops the operation of all actuators 8 and stops the movement of the bucket 1c after the bucket 1c has reached position and orientation P3 but before it has reached position and orientation P4. This reliably prevents the bucket 1c from moving to position and orientation P4 and P5 in an attempt to forcibly achieve an unattainable target position and orientation. As a result, the shaping error of the bucket 1c is kept small at position and orientation P4 and P5, and the bucket 1c can work with high precision.

[0085] As described above, in the construction machine 30 of the second embodiment, if the controller 10 determines that at least one target position and attitude included in the target trajectory is unattainable, it stops the operation of all actuators 8 after the bucket 1c has reached the final target position and attitude that has been determined to be achievable, based on the determination information.

[0086] As a result, the construction machine 30 can forcibly stop the movement of the bucket 1c once it has reached the final target position that has been determined to be achievable. The construction machine 30 can more reliably prevent the control of the actuator 8 by the operation support function from becoming unstable. Therefore, the construction machine 30 can more reliably prevent a decrease in the working accuracy of the bucket 1c near the boundary of the bucket 1c's movable range. Thus, according to the second embodiment, even in cases where it is predicted that the bucket 1c will move outside the movable range due to operator operation, it is possible to provide a construction machine 30 equipped with an operation support function that can more reliably prevent work from continuing in a state of unstable control of the bucket 1c.

[0087] [Third Embodiment] A third embodiment of the present invention will be described with reference to Figures 12 to 15. In the third embodiment, the same components as in the first and second embodiments will not be described.

[0088] Figure 12 is a block diagram illustrating the functions of the controller 10 of the third embodiment. In Figure 12, a posture condition changing unit 10h is added compared to Figure 2. Otherwise, the controller 10 of the third embodiment is the same as the controller 10 of the first embodiment. Figure 13 is a diagram showing the posture condition table PC.

[0089] The controller 10 of the third embodiment includes a posture condition changing unit 10h that changes the posture conditions of the bucket 1c, which are set in advance by the posture condition setting device 7b. If the posture condition changing unit 10h determines that at least one target position posture included in the target trajectory is not achievable by the feasibility determination unit 10d, it changes the preset posture conditions based on the determination information. The posture condition changing unit 10h then outputs the changed posture conditions to the target trajectory calculation unit 10c, causing the target trajectory to be recalculated to satisfy the changed posture conditions. The target motion calculation unit 10f calculates the target motion speed of the actuator 8 based on the recalculated target trajectory, and the actuator control unit 10g calculates a control command to the actuator 8 based on the target motion speed calculated based on the recalculated target trajectory.

[0090] When the posture condition changing unit 10h changes a preset posture condition, it refers to the posture condition table PC shown in Figure 13, which is pre-stored in the controller 10, to make the change. The posture condition table PC defines multiple posture conditions to which different priorities are assigned according to the working efficiency of bucket 1c, which changes depending on the posture of bucket 1c relative to the design plane.

[0091] Figure 13 shows an example of a posture condition table PC that defines multiple posture conditions for the bucket 1c during shaping work. In the example shown in Figure 13, the posture condition table PC defines the identification number of the posture condition, the specific content of the posture condition, the constraints regarding the contact state of the bucket 1c in the posture condition, the constraints regarding the direction of movement of the bucket 1c in the posture condition, the actuator 8 that needs to be controlled in the posture condition, and the priority of the posture condition.

[0092] The constraints regarding the contact state of bucket 1c specify whether the contact state of bucket 1c with the design surface must be point contact, line contact, or surface contact. The constraints regarding the direction of movement of bucket 1c specify whether the direction of movement MV of bucket 1c must coincide with the orientation of the reference part of bucket 1c (for example, the orientation of the opening of bucket 1c). The actuators 8 that require control under posture conditions specify the type of actuator 8 that must be controlled at a minimum in order to satisfy the posture conditions.

[0093] Priority is assigned so that the posture conditions that result in higher work efficiency for bucket 1c when bucket 1c is working in a posture that satisfies the posture conditions are given priority. Posture condition PC5 with priority "5" is the posture condition with the highest work efficiency and the highest priority. Posture condition PC1 with priority "1" is the posture condition with the lowest work efficiency and the lowest priority. However, the higher the priority of a posture condition, the more actuators 8 that need to be controlled at a minimum to satisfy the posture condition, making it more difficult to achieve the posture of bucket 1c specified in the posture condition.

[0094] When the attitude condition changing unit 10h changes a preset attitude condition, it specifies an attitude of the bucket 1c that can be achieved by actuators 8 other than the actuator 8 that is outside the range of motion at the target position attitude that has been determined to be unattainable, and changes the attitude condition to one with a higher priority. Furthermore, the attitude conditions preset by the attitude condition setting device 7b are the attitude conditions desired by the operator. Therefore, it is preferable for the attitude condition changing unit 10h to change the attitude condition to one that specifies an achievable attitude of the bucket 1c, has a high priority, and is as close as possible to the attitude condition desired by the operator.

[0095] Figure 14 is a flowchart showing the processing steps of the controller 10 shown in Figure 12. The flowchart in Figure 14 is an excerpt of the processing steps of the controller 10 shown in Figure 12 that differ from the flowchart in Figure 4. The flowchart in Figure 14 is performed immediately after step S104 in Figure 4.

[0096] In step S401, the feasibility determination unit 10d determines whether all target positions and attitudes included in the target trajectory are feasible. If all target positions and attitudes included in the target trajectory are determined to be feasible, the feasibility determination unit 10d proceeds to step S108. If at least one target position and attitude included in the target trajectory is determined to be unfeasible, the feasibility determination unit 10d identifies the type of actuator 8 that is outside the range of motion for the unfeasible target position and attitude. The feasibility determination unit 10d then generates determination information including the identified type of actuator 8 and proceeds to step S402.

[0097] In step S402, the attitude condition changing unit 10h acquires judgment information and confirms the type of actuator 8 that is outside the movable range at the target position and attitude of the bucket 1c which has been determined to be impossible to achieve.

[0098] In step S403, the posture condition change unit 10h determines whether there is a changeable posture condition among the multiple posture conditions defined in the posture condition table PC. Specifically, the posture condition change unit 10h determines whether there is a posture condition among the multiple posture conditions defined in the posture condition table PC that defines a posture of the bucket 1c that can be achieved by actuator 8 other than actuator 8 that is outside the range of motion at the target position posture of the bucket 1c which has been determined to be impossible to achieve. If a changeable posture condition exists, the posture condition change unit 10h proceeds to step S404. If no changeable posture conditions exist, the posture condition change unit 10h proceeds to step S106.

[0099] In step S404, the attitude condition changing unit 10h changes the pre-set attitude condition to an attitude condition that has a higher priority and is achievable by actuators 8 other than actuator 8 that are outside the range of motion at the target position and attitude of the bucket 1c which has been determined to be unattainable.

[0100] In step S405, the attitude condition change unit 10h outputs the attitude conditions changed in step S404 to the target trajectory calculation unit 10c, and proceeds to step S103. The target trajectory is recalculated to satisfy the changed attitude conditions.

[0101] Figure 15 illustrates the trajectory and work accuracy of the bucket 1c controlled by the controller 10 of the third embodiment.

[0102] The upper part of Figure 15 shows an example of semi-automatic control during shaping work, where the controller 10 moves the bucket 1c from position P1 to P5 while ensuring that the bottom surface of the bucket 1c is in surface contact with the design surface S, similar to Figure 11. The lower part of Figure 15 shows examples of shaping errors of the bucket 1c at each position and position P1 to P5, similar to Figure 11. In Figure 15, similar to Figure 11, it is assumed that the target position and position that the bucket 1c can achieve is calculated for positions and positions P1 to P3, and the target position and position that the bucket 1c cannot achieve is calculated for position and position P4.

[0103] In the controller 10 of the third embodiment, as shown in Figure 15, the target position and orientation that the bucket 1c can achieve is calculated for position and orientation P1 to P3. Therefore, similar to the second embodiment shown in Figure 11, the shaping error of the bucket 1c is small, and the bucket 1c can work with high precision. On the other hand, at position and orientation P4, a target position and orientation that the bucket 1c cannot achieve is calculated. When the position and orientation of the bucket 1c reaches P4, the controller 10 of the third embodiment changes the orientation conditions (changed from PC4 to PC3 in Figure 15) and recalculates the target trajectory, and controls the operation of the actuator 8 based on the recalculated target trajectory. As a result, at position and orientation P4 and P5, the shaping error of the bucket 1c is suppressed as much as possible, while the operation of the actuator 8 continues. Therefore, compared to the second embodiment shown in Figure 11, the controller 10 of the third embodiment can expand the working range of the bucket 1c controlled by the operation support function, and can improve work efficiency.

[0104] As described above, in the construction machine 30 of the third embodiment, the controller 10 calculates a target trajectory according to posture conditions that constrain the posture of the bucket 1c with respect to the design plane, and if it is determined that at least one target position posture included in the target trajectory is unattainable, the controller 10 changes the posture conditions based on the determination information and recalculates the target trajectory, and controls the operation of the actuator 8 based on the recalculated target trajectory.

[0105] As a result, even if the construction machine 30 determines that at least one target position and posture is unattainable, it can relax the constraints on the posture of the bucket 1c and continue the operation of the actuator 8. The construction machine 30 can prevent the control of the actuator 8 by the operation support function from becoming unstable, while also preventing the working range of the bucket 1c from being reduced by the control of the actuator 8 by the operation support function. Therefore, the construction machine 30 can prevent a decrease in the working accuracy of the bucket 1c near the boundary of the movable range of the bucket 1c, while also preventing a decrease in the working efficiency of the bucket 1c. Thus, according to the third embodiment, even in cases where it is predicted that the bucket 1c will move outside the movable range due to operator operation, it is possible to provide a construction machine 30 equipped with an operation support function that can prevent work from continuing in an unstable state of control of the bucket 1c without reducing the working efficiency of the bucket 1c.

[0106] Furthermore, in the construction machine 30 of the third embodiment, the controller 10 has one of several posture conditions pre-set, each assigned a different priority according to the working efficiency of the bucket 1c, which changes depending on the posture of the bucket 1c relative to the design plane. When the controller 10 changes a pre-set posture condition, it has defined a posture of the bucket 1c that can be achieved by actuators 8 other than the actuator 8 that is outside the range of motion at the target position posture that is determined to be impossible to achieve, and changes to a posture condition with a higher priority.

[0107] As a result, the construction machine 30 can reliably prevent the control of the actuator 8 by the operation support function from becoming unstable, while preventing as much as possible the reduction in the working range of the bucket 1c due to the control of the actuator 8 by the operation support function. Therefore, the construction machine 30 can reliably prevent a decrease in the working accuracy of the bucket 1c near the boundary of the movable range of the bucket 1c, while preventing as much as possible a decrease in the working efficiency of the bucket 1c. Thus, according to the third embodiment, even in cases where it is predicted that the bucket 1c will go outside the movable range due to operator operation, it is possible to provide a construction machine 30 equipped with an operation support function that can further prevent work from continuing in an unstable state of control of the bucket 1c without further reducing the working efficiency of the bucket 1c.

[0108] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are included. For example, the embodiments described above are described in detail to make the present invention easier to understand, and are not necessarily limited to those comprising all the components described. Furthermore, it is possible to replace some of the components of one embodiment with components of another embodiment, and it is also possible to add components of another embodiment to the components of one embodiment. In addition, it is possible to add, delete, or replace some of the components of each embodiment with components of other embodiments.

[0109] Furthermore, each of the above-mentioned components, functions, processing units, or processing means may be implemented in hardware, in whole or in part, for example, by designing them as integrated circuits. Alternatively, each of the above-mentioned components or functions may be implemented in software by a processor interpreting and executing programs that implement each function. Information such as programs, tables, or files that implement each function can be stored in a recording device such as memory, a hard disk, or an SSD (solid state drive), or in a recording medium such as an IC card, SD card, or DVD.

[0110] Furthermore, the control lines and information lines shown are those deemed necessary for explanatory purposes, and not all control lines and information lines are necessarily shown in the actual product. In reality, it can be assumed that almost all components are interconnected.

[0111] 1...Working device, 1c...Bucket (working tool), 1d...Tilt rotator, 2,3...Vehicle body, 4...Attitude detection device, 7a...Operation detection device, 7d...Display device, 8...Actuator, 10...Controller, 30...Construction machine

Claims

1. A construction machine comprising: a multi-jointed work device rotatably connected to a vehicle body and including a work tool connected to a tilt rotator; a posture detection device for detecting posture information of the work device and the vehicle body; an actuator for driving the work device and the vehicle body; an operation detection device for detecting operator operation information for the actuator; and a controller that calculates a target trajectory which is time-series data of the future target position and posture of the work tool based on design surface information indicating the target shape of the work object, the posture information and the operation information, and controls the operation of the actuator so that the work tool follows the target trajectory, wherein the controller determines whether the target position and posture included in the target trajectory is achievable based on the mechanical constraints of the work device and the vehicle body, generates determination information including the type of actuator that is outside the range of motion in the target position and posture determined to be unachievable, and outputs the generated determination information.

2. The construction machine according to claim 1, further comprising a display device, wherein the controller determines that at least one of the target position and attitude included in the target trajectory is unattainable, and based on the determination information, causes the controller to display an alarm on the display device including the type of actuator that is outside the range of motion.

3. The construction machine according to claim 1, characterized in that, if the controller determines that at least one of the target position and attitude included in the target trajectory is unattainable, it stops the operation of only the actuator that is outside the range of motion based on the determination information.

4. The construction machine according to claim 1, characterized in that, if the controller determines that at least one of the target position and orientation included in the target trajectory is unattainable, it stops the operation of all the actuators after the position and orientation of the work tool has reached the final target position and orientation determined to be attainable, based on the determination information.

5. The construction machine according to any one of claims 2 to 4, wherein the controller calculates the target trajectory according to posture conditions that restrict the posture of the work tool with respect to the design surface, and if it is determined that at least one of the target position postures included in the target trajectory is unattainable, it changes the posture conditions based on the determination information and recalculates the target trajectory, and controls the operation of the actuator based on the recalculated target trajectory.

6. The controller has a set of a plurality of posture conditions, each assigned a different priority according to the working efficiency of the work tool, which changes depending on the posture of the work tool relative to the design surface, and when the controller changes the set of posture conditions, a posture of the work tool that can be achieved by an actuator other than the actuator that is outside the range of motion is defined, and the controller changes to the posture condition with the higher priority, as described in claim 5.

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