Patent Application
20230392347
The present invention relates to a work machine.
As a technology for improving work efficiency of a work machine typified by a hydraulic excavator, machine control (MC) is known which semiautomatically controls the operation of a work device (for example, a work device including a boom, an arm, and a bucket) according to an operation made by an operator of the work device who operates an operation device and conditions determined in advance. The machine control (hereinafter referred to simply as MC) assists the operator to operate the work device by, for example, maintaining a distal end position of the bucket in the work device at a distance determined in advance with respect to a target surface or maintaining the posture (angle) of the bucket at an angle determined in advance with respect to the target surface.
As a technology related to MC settings, Patent Document 1, for example, discloses a control system for a work vehicle having a work implement (work device). The work vehicle control system includes a first control lever of the work implement, a first operating member provided to the first control lever, and a controller that performs automatic control of the work implement. The controller performs the function of the automatic control assigned to the first operating member, according to an operation of the first operating member, when execution conditions including a condition that the first control lever is at a neutral position are satisfied.
In order to achieve appropriate operation assistance in MC, it is necessary to switch between the enabling and disabling of MC according to work contents and a work environment and set appropriate assistance contents, for example. In the conventional technology, the operator alternately selects the enabling and disabling of the automatic control by operating the operating member provided to the control lever. In such a case, however, if the operator forgets to operate the operating member, work may be performed while the automatic control is disabled. Consequently, excavation may possibly be performed beyond a design surface. In addition, when the work contents are set through an operation made by the operator, if the operator sets the work contents or the assistance contents erroneously, the work device may not be set in a desired posture. As a result, the work device may erroneously excavate a construction surface excessively or drop soil transported to the construction surface, so that sufficient work accuracy may not be obtained. That is, in the case as described above, an appropriate MC operation may be unable to be performed, and thus, the work accuracy may be decreased.
The present invention has been made in view of the above. It is an object of the present invention to provide a work machine that can perform an appropriate assisting operation in the machine control and consequently improve the work accuracy.
The present application includes a plurality of pieces of means for solving the above-described problems. As an example of the means, there is provided a work machine including a lower track structure, an upper swing structure that is swingable with respect to the lower track structure, an articulated front work implement that is attached to the upper swing structure and includes a plurality of front implement members rotatably coupled together, an operation device that outputs operation signals for driving the upper swing structure and the front work implement according to amounts of operations made by an operator, a plurality of front work implement actuators that individually drive the plurality of front implement members on the basis of driving signals generated according to the operation signals output from the operation device, a swing actuator that swing-drives the upper swing structure on the basis of the operation signal output from the operation device, a posture information sensor that senses posture information as information regarding postures of the upper swing structure and the front work implement, and a controller that performs operation correction control to output a driving signal to at least one of the plurality of front work implement actuators such that the front work implement is set in a predetermined position or posture on a predetermined target surface and within one area with respect to the target surface, on the basis of the operation signals output from the operation device and the posture information sensed by the posture information sensor. The work machine further includes a load information sensor that senses load information as information regarding a load on at least one hydraulic actuator of the plurality of front work implement actuators, and a work area setting device that sets a work area over the predetermined target surface. The controller determines a working status indicating a status related to present work of the work machine, on the basis of the operation signals output from the operation device, the posture information sensed by the posture information sensor, the load information sensed by the load information sensor, and the work area set by the work area setting device, decides an operation form indicating contents of an operation in the operation correction control of the front work implement, from a plurality of operation forms set in advance, according to the determined working status, and performs the operation correction control such that the front work implement moves according to the operation form.
According to the present invention, it is possible to perform an appropriate assisting operation in machine control and consequently improve the work accuracy.
Embodiments of the present invention will hereinafter be described with reference to the drawings. It is to be noted that, while a hydraulic excavator mounted with an articulated front work implement will be illustrated and described as an example of a work machine in the embodiments, the present invention is also applicable to other work machines provided with a front work implement.
A first embodiment of the present invention will be described with reference to
In
The front work implement 12 is of an articulated type and includes a plurality of front implement members (a boom 13, an arm 14, and a bucket (work tool) 15) that each rotate in a vertical direction and that are coupled together. A proximal end of the boom 13 is supported by a front portion of the upper swing structure 11 rotatably in the vertical direction. One end of the arm 14 is supported by an end portion (distal end) of the boom 13, which is opposite to the proximal end of the boom 13, rotatably in the vertical direction. The bucket 15 as a work tool is supported by the other end of the arm 14 rotatably in the vertical direction.
The boom 13, the arm 14, and the bucket 15 are rotationally driven by a boom cylinder 17, an arm cylinder 18, and a bucket cylinder 19, respectively, which are hydraulic actuators (front work implement actuators). Further, the upper swing structure 11 is swing-driven by a swing hydraulic motor 16 which is a hydraulic actuator (swing actuator). In addition, the lower track structure 10 is travel-driven by left and right travelling hydraulic motors, not illustrated, which are hydraulic actuators (travelling actuators).
The boom cylinder 17 includes a pressure sensor 32a and a pressure sensor 32b that serve as load information sensors for sensing load information as information regarding a load on the hydraulic actuator. The pressure sensor 32a senses a hydraulic pressure on a rod side, and the pressure sensor 32b senses a hydraulic pressure on a bottom side. Similarly, the arm cylinder 18 includes a pressure sensor 33a and a pressure sensor 33b that serve as the load information sensors. The pressure sensor 33a senses a pressure on a rod side, and the pressure sensor 33b senses a pressure on a bottom side. Hereinafter, the pressure sensors 32a and 32b and the pressure sensors 33a and 33b may collectively be referred to as a pressure sensor 32 and a pressure sensor 33, respectively.
In the operation room 22, control levers 24a and 24b (see
The controller 23 is constituted by a central processing unit (CPU), a memory, and an interface. The CPU executes a program stored in the memory in advance and performs processing on the basis of set values stored in the memory and a signal input from the interface. Then, the interface outputs a signal.
The display input device 26 is, for example, a pointing device such as a touch panel. The display input device 26 displays information and receives an instruction from the operator through a graphical user interface (GUI) displayed on a screen.
The upper swing structure 11, the boom 13, the arm 14, and the bucket 15 have inertial measuring devices (inertial measurement units (IMUs)) 27, 28, 29, and 30, respectively. Each of the inertial measuring devices serves as a posture information sensor for sensing posture information as information regarding the posture of a corresponding one of the members. Hereinafter, when there is a need to distinguish these inertial measuring devices from one another, the respective inertial measuring devices will be referred to as a machine body inertial measuring device 27, a boom inertial measuring device 28, an arm inertial measuring device 29, and a bucket inertial measuring device 30. The relative positions where the inertial measuring devices 27, 28, 29, and 30 are attached to the respective members can be obtained from design information or the like. Thus, the relative rotational angles of the upper swing structure 11, the boom 13, the arm 14, and the bucket 15 can be estimated on the basis of sensing results (angular velocities and accelerations) from the inertial measuring devices 27, 28, 29, and 30.
In addition, two global navigation satellite system (GNSS) antennas 31a and 31b which are positional information sensors for sensing positional information are attached to an upper portion of the upper swing structure 11. Each of the GNSS antennas 31a and 31b has a position computing function of computing a signal received from an artificial satellite, to thereby compute the positional information. The GNSS antennas 31a and 31b can estimate the azimuth (orientation) of the upper swing structure 11 from a difference between the positional information obtained by the GNSS antenna 31a and the positional information obtained by the GNSS antenna 31b. Hereinafter, the two GNSS antennas 31a and 31b may collectively be referred to as a GNSS antenna 31.
The control lever 24 disposed in the operation room 22 includes the two control levers 24a and 24b that are swingable forward, rearward, leftward, and rightward. Each of the two control levers 24a and 24b of the control lever 24 is capable of receiving, as input, operation amounts of a total of four axial swings in a forward-rearward direction and a left-right direction. By generating driving signals in the controller 23 on the basis of operation signals generated according to the operation amounts of swinging operations of the control lever 24, it is possible to drive the swing hydraulic motor 16, the boom cylinder 17, the arm cylinder 18, and the bucket cylinder 19 individually according to the operations of the control lever 24. In addition, operation buttons 25a and 25b (see
In
The control valves 34, 35, 36, and 37 are driven by hydraulic pressures (pilot pressures) of the hydraulic fluids delivered from the pilot pump 40. The hydraulic fluids delivered from the pilot pump 40 are introduced into directional control valves 34a, 35a, 36a, and 37a via solenoid proportional pressure reducing valves 34b and 34c, 35b and 35c, 36b and 36c, and 37b and 37c of the control valves 34, 35, 36, and 37. The solenoid proportional pressure reducing valves 34b and 34c, 35b and 35c, 36b and 36c, and 37b and 37c are controlled on the basis of current commands output from the controller 23, so that the driving of the directional control valves 34a, 35a, 36a, and 37a is controlled. After the hydraulic fluids are supplied from the hydraulic pump 39 to the directional control valves 34a, 36a, and 37a, the flow rates of hydraulic fluids to be distributed to the hydraulic actuators 16, 17, 18, and 19 are adjusted according to operations of the solenoid proportional pressure reducing valves 34b and 34c, 35b and 36b and 36c, and 37b and 37c.
The hydraulic pump 39 is of a variable displacement type. When a regulator 39a operates on the basis of a current command output from the controller 23, the displacement of the hydraulic pump 39 is adjusted, and thus the flow rate of the hydraulic fluid to be delivered from the hydraulic pump 39 is controlled.
The bleed-off unit 43 includes a bleed-off valve 43a and a bleed-off valve solenoid proportional pressure reducing valve 43b. The bleed-off valve 43a allows some of the hydraulic fluids delivered from the hydraulic pump 39 to return to the hydraulic operating fluid tank 42. The bleed-off valve solenoid proportional pressure reducing valve 43b adjusts the flow rate of the hydraulic fluid to be released by the bleed-off valve 43a. Some of the hydraulic fluids delivered from the hydraulic pump 39 are discharged to the hydraulic operating fluid tank 42 when the bleed-off valve 43a makes a hydraulic line communicate with the hydraulic operating fluid tank 42. The bleed-off valve 43a is driven by a pilot pressure adjusted by the bleed-off valve solenoid proportional pressure reducing valve 43b. That is, the flow rate of the hydraulic fluid returning to the hydraulic operating fluid tank 42 via the bleed-off valve 43a is controlled by the pilot pressure adjusted by the bleed-off valve solenoid proportional pressure reducing valve 43b on the basis of a current command output from the controller 23.
The controller 23 is connected to the control lever 24, the operation button 25, the display input device 26, the inertial measuring devices 27, 28, 29, and 30, and the GNSS antenna 31. The controller 23 outputs current command signals for driving the solenoid proportional pressure reducing valves 34b and 34c, 35b and 35c, 36b and 36c, 37b and 37c, and 43b and the regulator 39a on the basis of respective input signals from the control lever 24, the operation button 25, the display input device 26, the inertial measuring devices 27, 28, 29, and 30, and the GNSS antenna 31, and drives the hydraulic actuators 16, 17, 18, and 19, the hydraulic pump 39, and the bleed-off unit 43. Thus, the controller 23 controls the operation of the hydraulic excavator 1.
In the present embodiment, a system within the controller 23 is executed as a combination of some programs. The controller 23 receives instruction signals from the control lever 24, the operation button 25, and the display input device 26 and sensing signals from the inertial measuring devices 27, 28, 29, and 30, a rotational angle meter 47, and the GNSS antenna 31 via interfaces, performs processing in the CPU, and then outputs, via interfaces, driving signals for individually driving the control valves 34, 35, 36, and 37, the hydraulic pump 39, and the bleed-off unit 43.
In
Next, an example of the details of work performed by the hydraulic excavator according to the embodiment of the present invention under the operation correction control (assisting operation) and the like.
As illustrated in
When such slope face shaping work is executed, the operation correction control (assisting operation) is performed to assist in the excavating operation on the target surface 5 such that the claw tip of the bucket 15 does not reach a position below the target surface 5, that is, the claw tip of the bucket 15 is moved along the target surface 5. In addition, in the operation of pressing the bucket 15 against the target surface 5, adjustment of the angle of the bucket 15 is assisted such that the bottom surface of the bucket 15 coincides with the target surface 5 while the claw tip of the bucket 15 is moved along the target surface 5. By performing the assisting operation in this way, accuracy of the slope face shaping work can be improved.
Moreover, in the operation of transporting the soil excavated by the target surface 5 to the stock 4 and the operation of transporting the soil scooped from the stock 4 to the target surface 5, the adjustment of the angle of the bucket 15 is assisted such that an opening plane where the bucket 15 is open is horizontal, so that the soil being transported can be prevented from dropping from the bucket Thus, extra work such as cleaning can be reduced, and work accuracy and work efficiency can be improved.
As illustrated in
When such groove excavation work is executed, the operation correction control (assisting operation) is performed to assist in the excavating operation on the target surface 5 such that the claw tip of the bucket 15 does not reach a position below the target surface 5, that is, the claw tip of the bucket 15 is moved along the target surface 5, so that the work accuracy can be improved.
Moreover, in the operation of transporting the soil excavated in forming the groove 3 to the stock 4 and the operation of transporting the soil scooped from the stock 4 to the groove 3, the adjustment of the angle of the bucket 15 is assisted such that the opening plane of the bucket 15 is horizontal, so that the soil being transported can be prevented from dropping from the bucket 15. Thus, extra work such as cleaning can be reduced, and the work accuracy and the work efficiency can be improved.
That is, as illustrated in
The work tool position and posture computing section 50 computes the distal end position (claw tip position) and posture (angle) of the bucket 15 as posture information regarding the hydraulic excavator 1 by using variables defined in
A distal end position (claw tip position) Pbk of the bucket 15 with respect to the origin Og of the excavator coordinate system can be obtained by using a swing angle θsw of the upper swing structure 11, a swing angle θbm of the boom 13, a swing angle θam of the arm 14, and a swing angle θbk of the bucket 15 as well as lengths Lf1, Lf2, Lbm, Lam, and Lbk of the respective members, and applying a D-H method (Denaviet-Hartenberg notation) or the like with the hydraulic excavator 1 as a link structure constituted of four links, that is, obtaining a product of simultaneous transformation matrices defined for the respective links.
Here, relations between the distal end position Pbk=(Xbk, Ybk, Zbk) of the bucket 15, an angle (Pitch_bk) formed between the horizontal plane (global coordinate system) and the excavator coordinate system, and the angles (θsw, θbm, θam, and θbk) between the respective members can be expressed by the following vector equations (Equation 1) to (Equation 3). Incidentally, “{circumflex over ( )}T” in (Equation 1) and (Equation 2) below represents transposition.
r=[Xbk,Ybk,Zbk,Pitch_bk]{circumflex over ( )}T (Equation 1)
q=[θsw,θbm,θam,θbk]{circumflex over ( )}T (Equation 2)
r=F(q) (Equation 3)
As illustrated in
As illustrated in
In the present embodiment, a case where the target surface 5 and the upper surface of the work area 7 are defined to be parallel with each other and where the size of the work area 7 is set by indicating one of the four representative points constituting the upper surface on the work area adjustment display 91 has been described by way of example. It is to be noted, however, that the configuration is not limited to this. For example, such a configuration may be adopted that distances from the target surface 5 to a plurality of points among the four representative points constituting the upper surface of the work area 7 can be adjusted individually.
In addition, when the size of the work area 7 is set by depressing of the confirmation button 95 on the work area setting screen of the display input device 26, an intra-work area bucket setting screen 92 is next displayed on the display input device 26. On the intra-work area bucket setting screen 92, the details of the assisting operation (operation form) for the bucket 15 within the work area 7 is set. The intra-work area bucket setting screen 92 displays a bucket height adjustment display 93 and receives a setting of the claw tip position of the bucket 15 (distance from the target surface 5) made by the operator. The intra-work area bucket setting screen 92 also displays a bucket posture adjustment display 94 and receive a setting of the posture (angle with respect to the horizontal plane) of the bucket 15 made by the operator. Incidentally, on the intra-work area bucket setting screen 92, the claw tip position and posture of the bucket 15 are set to correspond to each of a plurality of kinds of operation forms.
The kinds of operation forms of the assisting operation include a “bucket posture maintaining mode,” a “claw tip position designating mode,” and a “bucket horizontal maintaining mode.” The “bucket posture maintaining mode” is an operation form in which the angle of the bucket 15 is controlled such that the bottom surface of the bucket 15 is made to coincide with the target surface 5. In addition, the “claw tip position designating mode” is an operation form in which the position of the bucket 15 is controlled such that the claw tip of the bucket 15 is made to coincide with the target surface 5. Moreover, the “bucket horizontal maintaining mode” is an operation form in which the angle of the bucket 15 is controlled such that the opening plane of the bucket 15 is held horizontal.
The work tool operation form setting section 52 sets an operation form on the basis of the instruction input by the operator to the display input device 26, and stores the operation form in the work tool operation form storage section 53.
Next, working status determination processing in the working status determining section 54 will be described. The working status determining section 54 performs work type determination processing and work tool state determination processing as the working status determination processing for determining a working status indicating the status of the work of the hydraulic excavator 1. In the work type determination processing, a work type that is a classification indicating the state of the work being performed by the hydraulic excavator 1 is determined on the basis of the computation result from the work tool position and posture computing section 50 and the settings made by the work target setting section 51. In addition, in the work tool state determination processing, a work tool state that is the state of the bucket 15 is determined on the basis of the sensing results from the pressure sensors 32 and 33 and the computation result from the work tool position and posture computing section 50. Incidentally, the working status determination processing (the work type determination processing and the work tool state determination processing) in the controller 23 is repeatedly performed at intervals of a unit processing time (for example, a sampling time) determined in advance.
In the work type determination processing, the work type, which is the classification indicating the state of the work being performed by the hydraulic excavator 1, is set on the basis of the position and operation direction of the front work implement 12 (specifically, the bucket 15).
As illustrated in
The transformation of the representative points Pt1 to Pt4 and Pt1′ to Pt4′ and the normal vector n from the global coordinate system to the machine body coordinate system can be performed according to (Equation 4) to (Equation 6) below using a simultaneous transformation matrix Tsh (here, suppose that “l” is a positive integer indicating a number).
Ptl=(Tsh{circumflex over ( )}−1)×Pt (Equation 4)
Ptl′=(Tsh{circumflex over ( )}−1)×Pt′ (Equation 5)
nl=(Tsh{circumflex over ( )}−1)×(Pt+n)−Ptl (Equation 6)
Next, whether or not a claw tip position Pst of the bucket 15 is within the work area 7 is determined on the basis of the computation result from the work tool position and posture computing section 50 and the settings made by the work target setting section 51 (step S120).
Whether or not the claw tip position Pst of the bucket 15 is within the work area 7 can be determined, for example, by using the magnitude of an inner product of a normal to each surface of a hexahedron formed by the representative points Pt1 to Pt4 and Pt1′ to Pt4′, the normal extending in a direction towards the area, and a vector connecting each representative point and the claw tip position Pst of the bucket 15 to each other. For example, as illustrated in
Next, a movement destination of the claw tip position Pst of the bucket 15 corresponding to an operation made by the operator of the hydraulic excavator 1, that is, a demanded claw tip position Pest demanded by the operator, is predicted on the basis of an operation signal output from the control lever 24, and whether a result of the prediction (demanded claw tip position Pest) is within the work area 7 is determined (step S130).
The demanded claw tip position Pest can be obtained by (Equation 7) and (Equation 8) below. In the following Equations, ωlev represents angular velocity target values of the angles θsw, θbm, θam, and θbk of the respective parts which are obtained by geometric transformation of speed target values of the swing hydraulic motor 16, the boom cylinder 17, the arm cylinder 18, and the bucket cylinder 19, the speed target values being proportional to operation amounts (operation signals) of the control lever 24, and an estimated time Δtest determined in advance is used.
J(q)=∂F(q)/∂q (Equation 7)
Pest=Pst+J(q)×ωlev×Δtest (Equation 8)
Whether or not the demanded claw tip position Pest is located within the work area 7 can be determined by subjecting the obtained demanded claw tip position Pest to computation similar to that of step S120.
Next, whether the present claw tip position Pst of the bucket 15 is within the work area 7 is determined on the basis of a result of the computation in step S120 (step S140). When a result of the determination is YES, whether the demanded claw tip position Pest is within the work area 7 is next determined on the basis of a result of the computation in step S130 (step S150).
When a result of the determination in step S150 is YES, that is, when both the claw tip position Pst and the demanded claw tip position Pest of the bucket 15 are within the work area 7, the work type indicating the state of the work of the hydraulic excavator 1 is set to “intra-target work” which indicates that the work is being performed within the work area 7 (step S151). The processing is then ended.
In contrast, when the result of the determination in step S150 is NO, that is, when the present claw tip position Pst of the bucket 15 is within the work area 7 but the demanded claw tip position Pest is outside the work area 7, the work type is set to “target leaving work” which indicates that the position of the bucket 15 is moving from the inside of the work area 7 towards the outside of the work area 7 (step S152). The processing is then ended.
In addition, when a result of the determination in step S140 is NO, that is, when the present claw tip position Pst of the bucket 15 is outside the work area 7, whether or not the demanded claw tip position Pest is outside the work area 7 is next determined on the basis of the result of the computation in step S130 (step S160).
When a result of the determination in step S160 is YES, that is, when both the present claw tip position Pst and the demanded claw tip position Pest of the bucket 15 are outside the work area 7, the work type indicating the state of the work of the hydraulic excavator 1 is set to “extra-target work” which indicates that work is being performed outside the work area 7 (step S161). The processing is then ended.
In contrast, when the result of the determination in step S160 is NO, that is, when the present claw tip position Pst of the bucket 15 is outside the work area 7 but the demanded claw tip position Pest is within the work area 7, the work type is set to “target approaching work” which indicates that the position of the bucket 15 is approaching the target surface 5 within the work area 7 from the outside of the work area 7 (step S162). The processing is then ended.
In the work tool state determination processing, the work tool state, which is the classification indicating the state of the bucket 15 (work tool), is set on the basis of the posture (angle) of the bucket 15 with respect to the target surface 5 and a load on the front work implement 12.
Incidentally, in the work tool state determination processing, the work tool state includes both a filling state of the bucket 15 (determination result indicating whether or not the bucket 15 is filled with soil) and a coincidence state of the bucket 15 (determination result indicating whether or not the bottom surface of the bucket is close to a state of coinciding with the target surface Each of the states is stored independently.
Incidentally, as the work tool state, a work tool state at a time of a previous processing cycle is taken over and stored. Here, it is assumed that, as initial values, the filling state is a “soil unfilled state” and the coincidence state is a “posture coincidence state,” for example.
As illustrated in
When a result of the determination in step S200 is YES, that is, when the bottom pressure Pam of the arm cylinder 18 is higher than the threshold value Pth_am and the work tool state (filling state) is the “soil unfilled state,” an excavation start flag indicating that the excavating operation is started is set to “ON” (step S210).
In the excavating operation by the hydraulic excavator 1, the arm 14 is driven in a crowding direction, that is, the arm cylinder 18 is extended. Hence, as illustrated in
Next, when the result of the determination in step S200 is NO or when the processing of step S210 is ended, whether or not the bottom pressure Pam of the arm cylinder 18 is equal to or lower than the threshold value Pth_am determined in advance and the excavation start flag is “ON” is next determined on the basis of the sensing result from the pressure sensor 33 and the stored contents of the work tool state (filling state) (step S220).
When a result of the determination in step S220 is YES, that is, when the bottom pressure Pam of the arm cylinder 18 is equal to or lower than the threshold value Pth_am and the excavation start flag is “ON,” the excavation start flag is set to “OFF,” and an excavation end flag indicating that the excavating operation is ended is set to “ON” (step S230).
When the excavating operation by the hydraulic excavator 1 is ended, the bottom pressure Pam of the arm cylinder 18 becomes low, as illustrated in
Next, when the result of the determination in step S220 is NO or when the processing of step S230 is ended, whether or not a bottom pressure Pbm of the boom cylinder 17 is higher than a threshold value Pth_bm determined in advance and an angle θst of the bottom surface of the bucket 15 with respect to the horizontal plane is smaller than a threshold value θth_hr determined in advance and the excavation end flag is “ON” is then determined on the basis of the sensing result from the pressure sensor 32, the contents of the excavation end flag, and the computation result from the work tool position and posture computing section 50 (step S240). Incidentally, the angle θst can be computed as a sum of the angles θbm, θam, and θbk and an angle formed between the opening plane and the bottom surface of the bucket 15.
When a result of the determination in step S240 is YES, that is, when the bottom pressure Pbm of the boom cylinder 17 is higher than the threshold value Pth_bm and the angle θst is smaller than the threshold value th_hr and the excavation end flag is “ON,” the excavation end flag is set to “OFF,” and the work tool state (filling state) is set to a “soil filled state” which indicates that the bucket 15 is filled with soil (step S250).
In the transporting operation performed by the hydraulic excavator 1 after the excavating operation, the bucket 15 is filled with soil, and therefore, the weight of the bucket 15 is increased. Thus, as illustrated in
Next, when the result of the determination in step S240 is NO or when the processing of step S250 is ended, whether or not the angle θst of the bottom surface of the bucket 15 with respect to the horizontal plane is equal to or higher than the threshold value θth_hr determined in advance is then determined on the basis of the computation result from the work tool position and posture computing section 50 (step S260).
When a result of the determination in step S260 is YES, that is, when the opening plane of the bucket 15 is not horizontal, the work tool state (filling state) is set to the “soil unfilled state,” which indicates that the bucket 15 is not filled with soil (step S270).
As illustrated in
Next, when the result of the determination in step S260 is NO or when the processing of step S270 is ended, whether or not the angle θst of the bottom surface of the bucket 15 with respect to the horizontal plane is smaller than a sum of an angle θtgt formed between the target surface 5 and the horizontal plane and a threshold value θth determined in advance and the angle θst is larger than a difference (θtgt−θth) between the angle θtgt and the threshold value θth is then determined (step S280).
When a result of the determination in step S280 is YES, the work tool state (coincidence state) is set to the “posture coincidence state” which indicates that the orientations of the bottom surface of the bucket 15 and the target surface 5 substantially coincide with each other (step S281). The processing is then ended. In contrast, when the result of the determination in step S280 is NO, the work tool state (coincidence state) is set to a “posture non-coincidence state” which indicates that the angle of the bottom surface of the bucket 15 and the angle of the target surface 5 do not coincide with each other (step S282). The processing is then ended.
As illustrated in
Next, operation form invocation processing in the work tool operation form invoking section 55 will be described. The work tool operation form invoking section 55 performs operation form readout processing for reading an operation form stored in the work tool operation form storage section 53, on the basis of a processing result of the working status determination processing (the work type determination processing and the work tool state determination processing) in the working status determining section 54. Incidentally, the operation form readout processing in the controller 23 is repeatedly performed at intervals of a unit processing time (for example, a sampling time) determined in advance.
As illustrated in
When a result of the determination in step S310 is YES, that is, when the work type has changed to the target approaching work and the work tool state is the posture coincidence state, the “bucket posture maintaining mode” is read out from the work tool operation form storage section 53 and set as an operation form (step S320).
A state in which the work type has changed from the extra-target work to the target approaching state can be considered to be a state in which the bucket 15 is to enter the work area 7, and can thus be determined to be a working status in which the operator of the hydraulic excavator 1 intends to make a transition to the work in the vicinity of the target. In addition, at this time, when the work tool state is the posture coincidence state, it can be determined that it is a working status in which the bottom surface of the bucket 15 is to coincide with the target surface 5. That is, it is possible to determine, on the basis of the determinations in steps S300 and S310, whether or not an assisting operation appropriate for the present working status is the “bucket posture maintaining mode,” which is the operation form in which the angle of the bucket 15 is controlled to make the bottom surface of the bucket 15 coincide with the target surface 5.
Next, when the result of the determination in step S300 or S310 is NO or when the processing of step S320 is ended, whether or not the work type has changed to the intra-target work is then determined (step S330). In addition, when a result of the determination in step S330 is YES, whether or not the work tool state is the soil filled state is determined (step S340).
When a result of the determination in step S340 is NO, that is, when the work type has changed to the intra-target work and the work tool state is not the soil filled state, the “claw tip position designating mode” is read out from the work tool operation form storage section 53 and set as an operation form (step S341).
A state in which the work type has changed to the intra-target work can be considered to be a state in which the work is being performed within the work area 7. In addition, at this time, when the work tool state is not the soil filled state, it can be determined that it is a working status in which excavation is to be performed within the work area. That is, it is possible to determine, on the basis of the determinations in steps S330 and S340, whether or not an assisting operation appropriate for the present working status is the “claw tip position designating mode,” which is the operation form in which the position of the bucket 15 is controlled to make the claw tip of the bucket 15 coincide with the target surface 5. Incidentally, when the result of the determination in step S340 is YES, that is, when the work tool state is the soil filled state, it can be estimated that the work of strewing soil, such as laying and leveling of the soil, is performed within the work area 7, and therefore, such control that makes the claw tip of the bucket 15 coincide with the target surface 5 is not performed.
Next, when the result of the determination in step S330 is NO, when the result of the determination in step S340 is YES, or when the processing of step S341 is ended, whether or not the work type has changed to the target leaving work is then determined (step S350). When a result of the determination in step S350 is YES, the bucket posture maintaining mode is cancelled (step S360), and the claw tip position designating mode is cancelled (step S370).
A state in which the work type has changed to the target leaving work is a state in which the bucket 15 is to leave the work area 7, and can be determined to be a working status in which the operator of the hydraulic excavator 1 intends to make a transition to the work at a place separated from the target surface 5. That is, it is possible to determine, on the basis of the determination in step S350, whether or not to cancel the assisting operation for work on the target surface 5.
Next, when the result of the determination in step S350 is NO or when the processing of steps S360 and S370 is ended, whether or not the work type is one of the extra-target work and the intra-target work is then determined (step S380). In addition, when a result of the determination in step S380 is YES, whether or not the work tool state has changed to the soil filled state is next determined (step S390).
When a result of the determination in step S390 is YES, that is, when the work type is the extra-target work or the intra-target work and the work tool state has changed to the soil filled state, the “bucket horizontal maintaining mode” is read out from the work tool operation form storage section 53 and set as an operation form (step S400).
A state in which the work tool state has changed to the soil filled state at a position separated from the target surface 5 in the case of the extra-target work or within the work area in the case of the intra-target work can be determined to be a working status in which transportation is started after soil is excavated. That is, it is possible to determine, on the basis of the determinations in steps S380 and S390, whether or not to set the “bucket horizontal maintaining mode,” which is the operation form in which the angle of the bucket 15 is controlled so as to hold the opening plane of the bucket 15 horizontal.
Next, when the result of the determination in step S380 or S390 is NO or when the processing of step S400 is ended, whether or not the work tool state is the soil filled state is next determined (step S410). In addition, when a result of the determination in step S410 is YES, whether or not the work type has changed to one of the intra-target work and the extra-target work is next determined (step S420).
When a result of the determination in step S420 is YES, that is, when the work tool state is the soil filled state and the work type is the intra-target work or the extra-target work, the bucket horizontal mode is cancelled (step S430). The processing is then ended. In addition, the processing is ended when the result of the determination in either step S410 or S420 is NO.
A state in which the work tool state is the soil filled state and the work type has changed to the intra-target work or the extra-target work can be determined to be a working status in which soil has been transported to a position separated from the target surface 5 within the work area 7 or to above the target surface 5 outside the work area 7. That is, it is possible to determine, on the basis of the determinations in steps S410 and S420, whether or not to cancel the bucket horizontal maintaining mode to enable a soil discharge operation.
Next, computation processing in the work tool operation correction amount computing section 56 will be described. The work tool operation correction amount computing section 56 computes a control amount (operation correction amount) to perform the assisting operation, on the basis of the computation result from the work tool position and posture computing section 50, the settings made by the work target setting section 51, the work type invoked by the work tool operation form invoking section 55, and the operation state of the operation button 25.
The work tool operation correction amount computing section 56 first calculates a point Pn on the target surface 5 that is the closest to a distal end position Pst of the bucket 15, by using (Equation 9) below.
Pn=Ptl−n·(Pst−Pt1)/|n|{circumflex over ( )}2×n (Equation 9)
Incidentally, “|n|” in the above (Equation 9) represents the norm of a vector.
In addition, an angular difference dθ between the angle θst of the bottom surface of the bucket 15 with respect to the horizontal plane and the angle of the target surface 5 or the horizontal is computed. With this, a movement correction speed vadj for the distal end position Pst of the bucket 15 is calculated by (Equation 10) below by using predetermined gains Kadjp and Kadjθ.
vadj=[Kadjp×(Pst−Pn),Kadjθ×dθ]{circumflex over ( )}T (Equation 10)
Then, each swing angular velocity of the hydraulic excavator 1 is computed by converting the movement correction speed vadj. In addition, when a Jacobian matrix J corresponding to the relations between (Equation 1) to (Equation 3) is used, a correction swing angular velocity ωadj of the hydraulic excavator 1 can be expressed as in (Equation 11) and (Equation 12) below by using the speed vadj of the distal end position Pst of the bucket 15.
J(q)=∂F(q)/∂q (Equation 11)
ωadj=(J(q){circumflex over ( )}−1)×vadj (Equation 12)
Then, the work tool operation correction amount computing section 56 selects an actuator(s) to which ωadj is to be applied, on the basis of the setting made by the work tool operation form invoking section 55. For example, in the bucket horizontal maintaining mode or the bucket posture maintaining mode for correcting the posture of the bucket only a component of ωadj related to rotation of the bucket 15 is extracted. In the claw tip position designating mode, only components of ωadj related to rotation of the boom 13 and the arm 14 are extracted. In addition, ωadj is set to 0 (zero) when the operation button is depressed, so that the assisting operation is forcibly prevented from being performed when the hydraulic excavator 1 performs an operation different from an intention of the operator.
The work implement control amount computing section 57 computes and outputs current commands (driving signals) for driving the control valves 34, 35, 36, and 37, the hydraulic pump 39, and the bleed-off unit 43, on the basis of an operation instruction amount indicated by the operation signal output from the control lever 24 and of the correction swing angular velocity ωadj output by the work tool operation correction amount computing section 56. That is, the work implement control amount computing section 57 converts the operation amount of the control lever 24 into a swing angular velocity command value ωope of the hydraulic excavator 1 which is proportional to the operation amount, and calculates a current command Cctrl by (Equation 13) below by using the correction swing angular velocity ωadj and a predetermined conversion map Kctrl(q) of swing angular velocity and the current command.
Cctrl=Kctrl(q)×(ωope+ωadj) (Equation 13)
Next, a method of displaying the state of the assisting operation to the operator will be described.
Effects of the present embodiment configured as described above will be described.
In order to achieve appropriate operation assistance in MC, it is necessary to switch between the enabling and disabling of MC according to the work contents and a work environment and set appropriate assistance contents. In the conventional technology, the operator alternately selects the enabling and disabling of the automatic control by operating the operating member provided to the control lever. In such a case, however, if the operator forgets to operate the operating member, work may be performed while the automatic control is disabled. Consequently, excavation may possibly be performed beyond a design surface. In addition, when the work contents are set through an operation made by the operator, if the operator sets the work contents or the assistance contents erroneously, the work device may not be set in a desired posture. As a result, the work device may erroneously excavate a construction surface excessively or drop the soil transported to the construction surface, so that sufficient work accuracy may not be obtained. For example, in work of shaping the terrain profile of a construction object into a desired shape, a shaping operation and a transporting operation may alternately be performed. In the shaping operation, while the position and posture of the bucket are adjusted, the hydraulic excavator 1 excavates soil with the bottom surface of the bucket made to coincide with the construction surface to be shaped. In the transporting operation, while the bucket opening plane is kept parallel to the horizontal plane so as not to drop soil onto the shaped surface, the hydraulic excavator 1 moves the soil that becomes a surplus during the shaping. In the shaping work where the automatic control is performed such that the posture of the bucket corresponds to a predetermined angle, if the operating member is operated erroneously and the automatic control of the shaping operation and the transporting operation is performed conversely, the bucket may not be set in a desired posture. As a result, the hydraulic excavator 1 may erroneously excavate the construction surface excessively or drop the transported soil onto the construction surface, so that sufficient work accuracy may not be obtained. That is, in such a case as described above, an appropriate MC operation may be unable to be performed, and thus, the work accuracy may be decreased.
On the other hand, in the present embodiment, the work machine (hydraulic excavator 1) includes the lower track structure 10; the upper swing structure 11 that is swingable with respect to the lower track structure 10; the articulated front work implement 12 that is attached to the upper swing structure 11 and includes a plurality of front implement members (the boom 13, the arm 14, and the bucket rotatably coupled together; the operation device (control lever 24) that outputs operation signals for driving the upper swing structure 11 and the front work implement 12 according to amounts of operations made by the operator; a plurality of front work implement actuators (the boom cylinder 17, the arm cylinder 18, and the bucket cylinder 19) that individually drive the plurality of front implement members on the basis of driving signals generated according to the operation signals output from the operation device; the swing actuator (swing hydraulic motor 16) that swing-drives the upper swing structure 11 on the basis of the operation signal output from the operation device; the posture information sensor (inertial measuring devices 27 to that senses posture information as information regarding the postures of the upper swing structure 11 and the front work implement 12; and the controller (controller 23) that performs the operation correction control to output a driving signal to at least one of the plurality of front work implement actuators such that the front work implement 12 is set in a predetermined position or posture on the predetermined target surface 5 and within one area with respect to the target surface, on the basis of the operation signals output from the operation device and the posture information sensed by the posture information sensors. The work machine further includes the load information sensor (pressure sensors 32 and 33) that senses load information as information regarding a load on at least one of the plurality of front work implement actuators, and a work area setting device (display input device 26) that sets the work area 7 over the predetermined target surface 5. The controller determines a working status indicating a status related to the present work of the work machine, on the basis of the operation signals output from the operation device, the posture information sensed by the posture information sensor, the load information sensed by the load information sensor, and the work area set by the work area setting device, decides an operation form indicating contents of an operation in the operation correction control of the front work implement, from a plurality of operation forms set in advance, according to the determined working status, and performs the operation correction control such that the front work implement moves according to the operation form. It is thus possible to perform an appropriate assisting operation in machine control and consequently improve the work accuracy.
A second embodiment of the present invention will be described with reference to
The present embodiment represents a case where a rotary tilt bucket 44 is used in place of the bucket 15 used as a work tool in the first embodiment.
In
A rotational angle meter 47 which is a posture information sensor is attached to the rotary tilt bucket 44 and is capable of sensing a rotational angle (rotary angle) of the rotary tilt bucket 44 about the rotational axis A6. In addition, an inertial measuring device 30 which is a posture information sensor can sense a rotational angle (tilt angle) about the rotational axis A5 in addition to a rotational angle about the rotational axis A4. That is, the orientation of the rotary tilt bucket 44 can be calculated on the basis of sensing results from the inertial measuring device 30 and the rotational angle meter 47.
In such a work machine, the position and posture of the rotary tilt bucket can be adjusted independently with three degrees of freedom with respect to the machine body of the hydraulic excavator 1, so that complex operations can be performed. With such a hydraulic excavator 1, the operation form of the work tool in the work tool operation form setting section 52 is not limited to the posture of the bucket 15 and the position of the claw tip as illustrated in the first embodiment, and, for example, a plurality of postures of the rotary tilt bucket 44 about the A5 axis and the A6 axis can be set individually, together with the direction in which the rotary tilt bucket 44 moves and the posture of the rotary tilt bucket 44 about the A4 axis.
In addition, the working status determining section 54 may determine the working status by a different method. For example, the working status may be computed by using a reaction force acting on the rotary tilt bucket 44, on the basis of the posture of the front work implement 12 and thrusts of the respective cylinders, the thrusts being computed on the basis of the pressures of the boom cylinder 17, the arm cylinder 18, and the bucket cylinder 19. Needless to say, a result of estimation of a payload of the soil within the rotary tilt bucket 44 may also be used.
In addition, the combination of the work area and the work tool operation form that are set by the work target setting section 51 and the work tool operation form setting section 52 is not limited to only one combination as in the first embodiment. For example, as in the laying and leveling work performed by the hydraulic excavator 1 provided with the rotary tilt bucket 44 illustrated in
Incidentally, an example has been described above in which the work implement control amount computing section 57 calculates the current command Cctrl by using the conversion map Kctrl(q) of the swing angular velocity and the current command. However, it is needless to say that the current command Cctrl may be computed by a different method and that the control command may be generated by using a map that uses a pressure of the hydraulic circuit or a control law of model predictive control or the like.
The other configurations are similar to those of the first embodiment.
The present embodiment configured as described above can also provide effects similar to those of the first embodiment.
It is to be noted that the present invention is not limited to the foregoing embodiments and includes various modifications and combinations of embodiments within a scope not departing from the spirit of the present invention. Further, the present invention is not limited to those including all of the configurations described in the foregoing embodiments and also includes those from which some of the configurations are omitted. In addition, a part or the whole of each of the configurations, the functions, and the like described above may be implemented by, for example, being designed in an integrated circuit or the like. Moreover, each of the configurations, the functions, and the like described above may be implemented by software causing a processor to interpret and execute a program for implementing the respective functions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-202727 | Dec 2020 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/041803 | 11/12/2021 | WO |
