JP5241690B2 - Work machine - Google Patents

Description

  The present invention relates to a work machine for rough terrain used on rough terrain such as slopes, overcoming obstacles, and uneven road surfaces, and in particular, has four or more traveling units capable of changing the vertical distance from an upper unit. Related to working machines.

  In recent years, in disaster recovery work such as earthquakes and forestry work, there is a demand for a work machine that can cope with a site that is difficult to enter with a work machine consisting of two fixed crawlers with lower traveling bodies provided on the left and right of the vehicle body. It is getting bigger. Conventionally known work machines that take into account such rough terrain sites are those disclosed in Patent Literature 1 and those disclosed in Patent Literature 2.

  In Patent Document 1, telescopic arms are provided on the front, rear, left and right sides of a chassis frame on which an upper swing body (upper unit) is rotatably mounted, and a crawler device or a running wheel type travel device (travel unit) is provided at the lower end of each telescopic arm. ) Is mounted so that it can be moved up and down. Further, in Patent Document 1, regarding the operation of the rough terrain work vehicle, the operator operates the expansion and contraction of the telescopic arm according to the unevenness of the road surface, so that the cab provided in the upper unit is kept horizontal. A technique for overcoming road surfaces is disclosed.

  On the other hand, Patent Document 2 includes four traveling bodies (traveling units) on the front, rear, left and right sides of the vehicle body, and the left and right of the bendable configuration for supporting the work machine body (upper unit) on the front traveling body and the rear traveling body. A leg joint is provided at the upper end of each of the left and right legs, and a hip joint shaft is provided for pivotally connecting the work machine body. By rotating the work machine body about the axis of the hip joint axis, the horizontal posture of the work machine body A traveling vehicle for rough terrain that maintains the above is disclosed. Also, this Patent Document 2 discloses a control in which a work machine body is provided with a pitch / roll angle sensor and an angular velocity sensor, and the posture of the work machine body is leveled according to the outputs of these sensors. Further, this Patent Document 2 includes a position detection unit for a hydraulic actuator for driving a leg, and suppresses an attitude leveling control command to the actuator near the lower limit of the actuator based on an output signal of the position detection unit. Technology is also disclosed.

JP 2000-335457 A JP 2008-213732 A

  By the way, in order to put into practical use a working machine having four traveling units as disclosed in Patent Documents 1 and 2, it is easy to keep the inclination angle of the upper unit at a desired value even when traveling on rough terrain. It is necessary to clear three problems: the unit does not lift off the road surface, and the vehicle height does not change or increase unnecessarily even when the traveling unit is driven up and down.

  That is, when the upper unit is inclined, it is difficult to maintain an appropriate posture for the operator to perform a lever operation or the like. Also, when the traveling unit is lifted off the ground, when the work machine is suddenly started or stopped, or when the center of gravity of the vehicle body is moved by excavating using the work front or turning the upper unit, etc. The upper unit tends to fall down in the direction of the unit. In addition, when the vehicle height increases, the center of gravity of the work machine increases and the stability of the vehicle body decreases.If the vehicle height changes repeatedly, the field of view rises and falls, making it difficult to see the road surface, etc. It is necessary to operate the lever to keep the constant. As a result, the operator who gets on the vehicle feels uneasy or the operability of the work machine deteriorates, increasing the operator's fatigue.

  In the invention described in Patent Document 1, the crawler device or the running wheel type traveling device constituting the traveling unit is supported by a telescopic cylinder type telescopic arm, and the upper revolving body is inclined or the crawler device is lifted. In this case, the operator must operate the lever according to the road surface shape and adjust the stroke of each telescopic arm. There is a problem that the work burden increases and the work efficiency is likely to decrease. In addition, technical measures against the issue of vehicle height are not mentioned.

  On the other hand, the invention described in Patent Document 2 includes a left and right front traveling unit, a left and right rear traveling unit, a work machine body in which a drive source and a work implement are arranged, and a front traveling unit and a rear traveling unit. A travel vehicle for rough terrain comprising a bendable left and right leg that supports the work machine body, and has a hip joint shaft that rotatably connects the work machine body to the upper end sides of the left and right leg bodies. Since the work machine body can be rotated and maintained in a horizontal posture around the axis, the work machine body is leveled with respect to the ground (road surface) and the floating leg is not affected by the movement of the left and right legs. Can be easily controlled. However, in the invention described in Patent Document 2, the difference in height between the left and right traveling parts cannot be made larger than that in Patent Document 1, and the subject of the change in vehicle height is left to the operator's operation. So there is room for improvement in this regard. In addition, since 11 active actuators are required to control the tilt angle of the work machine body and to suppress the floating legs, the configuration is complicated, and there is room for improvement in this respect.

  The present invention has been made in view of the actual situation of the prior art, and has an object of having a simple configuration, automatically setting the inclination angle and vehicle height of the upper unit to a desired state, and the travel unit. An object of the present invention is to provide a work machine for rough terrain that can automatically maintain ground contact.

  In order to solve the above-described problems, the present invention includes an upper unit having a driver's cab and a work front, and four or more leg units, one end of which is connected to the upper unit and swinging within a predetermined swing angle. The working machine having at least four or more traveling units supported for each leg unit and a controller for controlling the driving of each leg unit and each of the traveling units, the controller travels on rough terrain. In this case, the inclination angle of the upper unit is maintained within a preset threshold with respect to a preset target inclination angle, and the ground contact state between the traveling units and the rough road surface is maintained. In addition, within the range where the swing angle of each leg unit does not exceed the predetermined swing angle, a drive command for leg raising drive or leg lowering drive is output to each leg unit. And wherein the door.

  According to this configuration, the leg raising drive or leg lowering drive of each leg unit is automatically controlled by the controller, and the inclination angle of the upper unit is maintained within a preset threshold with respect to a preset target inclination angle. In addition, since the ground contact state between each traveling unit and the road surface of rough terrain is maintained, it is possible to prevent the occurrence of inconvenience due to the inclination of the upper unit and the floating of each traveling unit. And poor operability. In addition, there is no need to perform special operations for maintaining the inclination angle of the upper unit within the target inclination angle, and for maintaining the ground contact state between each traveling unit and the road surface of rough terrain. The operability of the machine is improved. Therefore, the operating efficiency of the work machine can be increased, the work time can be shortened, and the operator's fatigue can be reduced.

  The present invention further includes an upper unit inclination angle detection means for detecting an inclination angle of the upper unit, and the controller is configured such that the inclination angle of the upper unit detected by the upper unit inclination angle detection means is determined from the target inclination angle. The leg raising drive or the leg lowering drive of each leg unit is feedback-controlled so that the ground contact state between each running unit and the rough road surface is maintained within the threshold value.

  The present invention further includes a grounding force detecting means for detecting or estimating a grounding force acting on each traveling unit from the road surface of the rough terrain, and the controller detects the grounding force detected by the grounding force detecting means. The leg lowering drive of each leg unit is controlled so that the grounding force acting on each traveling unit becomes stronger than a preset first grounding force threshold value.

  According to such a configuration, the leg lowering drive of each leg unit is controlled so that the grounding force acting on each traveling unit detected by each grounding force detecting means is stronger than a preset first grounding force threshold. Since each traveling unit is simply in contact with the road surface, it can be prevented that the grounding force is hardly applied, and each traveling unit can be reliably pressed against the road surface. Therefore, idling of each traveling unit can be suppressed and traveling performance can be improved.

  The present invention further includes a vertical distance detecting means for detecting a vertical distance of each traveling unit with respect to the upper unit, wherein the controller is detected by the vertical distance detecting means, and the vertical distance of each traveling unit is detected. Controlling the leg raising drive or leg lowering drive of each leg unit so that the vehicle height defined by the maximum value is the minimum value at which the leg raising drive or leg lowering drive of each leg unit can be performed. It is characterized by.

  According to this configuration, the vehicle height is kept low because the leg raising drive or leg lowering drive of each leg unit is controlled so that the vehicle height becomes the minimum value at which each leg unit can be raised or lowered. Can improve the stability of the vehicle body.

  The present invention further includes a vertical distance detecting means for detecting a vertical distance of each traveling unit with respect to the upper unit, wherein the controller is detected by the vertical distance detecting means, and the vertical distance of each traveling unit is detected. The leg raising drive or leg lowering drive of each leg unit is controlled so that the vehicle height defined by the maximum value of the vehicle becomes a preset target vehicle height.

  According to such a configuration, since the leg raising drive or leg lowering drive of each leg unit is controlled so that the vehicle height becomes a preset target vehicle height, the vehicle height can be maintained at a constant height suitable for traveling or work. It is possible to improve driving safety and work efficiency.

  According to the present invention, when the deviation between the tilt angle of the upper unit detected by the upper unit tilt angle detecting means and the target tilt angle is equal to or greater than a preset tilt angle threshold, The traveling speed command output to the unit is suppressed more than when the deviation is equal to or less than the inclination angle threshold value.

  According to such a configuration, when the deviation between the tilt angle of the upper unit and the target tilt angle is equal to or greater than a preset tilt angle threshold, the travel speed command output to each travel unit is suppressed, so that the work machine is uneven. Even when traveling on rough terrain, the amount of change in the tilt angle of the upper unit per unit time proportional to the travel speed of the work machine can be reduced, and the tilt angle control of the upper unit can be facilitated. it can.

  According to the present invention, when the controller detects that each of the traveling forces detected by the respective grounding force detection means is less than a second grounding force threshold value set in advance, the traveling force is applied to each traveling unit. The traveling speed command output to the unit is suppressed more than when the grounding force acting on each traveling unit is equal to or greater than the second grounding force threshold.

  According to such a configuration, when any of the grounding forces acting on each traveling unit becomes equal to or less than a preset second grounding force threshold, the traveling speed command output to each traveling unit is suppressed. Even when traveling on rough terrain with large unevenness, the amount of change in the road surface height under each traveling unit per unit time proportional to the traveling speed of the work machine can be reduced, and the grounding acting on each traveling unit can be reduced. Force control can be facilitated.

  The present invention further includes traveling unit inclination angle detecting means for detecting an inclination angle of each traveling unit, and horizontal traveling speed detecting means for detecting or estimating a horizontal traveling speed of each traveling unit, wherein the controller includes: The amount of change per unit time of the tilt angle of the upper unit from the tilt angle of the travel unit detected by the travel unit tilt angle detection means and the horizontal travel speed of the travel unit detected by the horizontal travel speed detection means And the leg raising drive or leg lowering drive of each leg unit is feedforward controlled so as to cancel the amount of change.

  According to such a configuration, the amount of change per unit time of the inclination angle of the upper unit is estimated from the inclination angle of the traveling unit and the horizontal traveling speed of the traveling unit, and each leg unit is driven or lifted so as to cancel this amount of change. Since the leg lowering drive is feed-forward controlled, the tilt angle response itself of the upper unit that occurs during the feedback control based on the upper unit tilt angle detecting means, and the hydraulic actuator used for the leg raising drive or leg lowering drive of the leg unit. It becomes possible to prevent the vibration of the upper unit due to the response delay, and to control the inclination angle of the upper unit stably.

  According to the present invention, the controller automatically controls the leg raising or leg lowering drive of each leg unit, and the inclination angle of the upper unit is maintained within a preset threshold with respect to a preset target inclination angle. In addition, since the ground contact state between each traveling unit and the road surface of rough terrain is maintained, it is possible to prevent the occurrence of inconvenience due to the inclination of the upper unit and the floating of each traveling unit. Also, a special operation for maintaining the inclination angle of the upper unit within a preset threshold with respect to the target inclination angle, and a special operation for maintaining the ground contact state between each traveling unit and the road surface of rough terrain. Therefore, the operability of the work machine can be improved. Furthermore, it is only necessary to provide as many actuators as the number of traveling units provided in the vehicle body as actuators for the upper unit inclination angle control and floating leg suppression control, so the construction of the work machine is significantly simplified compared to the prior art. Can be

It is a side view showing the whole work machine structure concerning an embodiment. It is a figure which shows the system configuration | structure of the working machine which concerns on embodiment. It is a figure which shows the drive command calculation flow of each leg unit for the upper inclination angle control of the working machine which concerns on embodiment. It is a figure which shows the example of a response | compatibility with the leg angle and leg drive limitation gain in the leg drive limit suppression calculation of the working machine which concerns on embodiment. It is a side view which shows the state before climbing the slope of the working machine in which upper angle control is performed. It is a side view which shows a state when the front side traveling unit of the working machine in which the upper angle control is performed is applied to the sloping ground. It is a side view which shows the state which is climbing up the slope of the working machine in which upper angle control is performed. It is a side view which shows a state when the working machine in which upper angle control is performed climbs the slope, and the front traveling unit is applied to the upper flat ground. It is a side view which shows a state when climbing up the slope of the working machine in which upper angle control is performed. It is a figure which shows the drive command calculation flow of each leg unit for the upper inclination angle control of the working machine which concerns on embodiment. It is a figure which shows the example of a response | compatibility with the cylinder thrust and leg drive command in the crawler grounding control of the working machine which concerns on embodiment. It is a figure which shows the example of a response | compatibility with the cylinder thrust and leg drive limitation gain in the crawler grounding control of the working machine which concerns on embodiment. It is a side view which shows the state before traveling over the small obstacle of the working machine in which crawler grounding control is performed. It is a side view which shows a state when the left front side travel unit of the working machine in which crawler grounding control is performed has got on a small obstacle. It is a side view showing a state when the rear traveling unit of the work machine on which the left front traveling unit rides on the small obstacle is grounded to the road surface by the crawler grounding control. It is a figure which shows the drive flow of each leg unit for the low vehicle height attitude | position control of the working machine which concerns on embodiment. It is a side view showing a state when the work machine on which the low vehicle height attitude control is performed climbs an inclined ground and the front traveling unit is applied to an upper flat ground. It is a side view which shows a state when the work machine in which low vehicle height attitude | position control is performed has finished climbing the slope. It is a figure which shows the drive flow of each leg unit for the constant vehicle height control of the working machine which concerns on embodiment. It is a side view which shows a state when the work machine in which constant vehicle height control is performed has finished climbing the slope. It is a figure which shows the example of a response | compatibility with the upper inclination angle and driving | running | working suppression gain in the traveling speed suppression control of the working machine which concerns on embodiment. It is a figure which shows the example of a response | compatibility with the minimum cylinder thrust and traveling suppression gain in the traveling speed suppression control of the working machine which concerns on embodiment. It is a figure which shows the drive flow of each leg unit for the upper inclination angle control of the working machine which concerns on embodiment. It is a side view which shows the state in which the working machine in which upper inclination angle control is performed based on the inclination angle and horizontal advancing speed of a traveling unit climbs an inclined ground. It is a side view which shows the state when the left front side traveling unit of the working machine in which the upper inclination angle control is performed based on the inclination angle and the horizontal traveling speed of the traveling unit ride on a small obstacle. It is a side view which shows the state when the front left side traveling unit of the working machine in which the upper inclination angle control is performed based on the inclination angle and the horizontal traveling speed of the traveling unit finishes over the small obstacle. It is a side view which shows a state when the left rear side traveling unit of the working machine in which the upper inclination angle control is performed based on the inclination angle and the horizontal traveling speed of the traveling unit ride on a small obstacle. It is a side view which shows the state when the left rear traveling unit of the work machine in which the upper inclination angle control is performed based on the inclination angle and the horizontal traveling speed of the traveling unit finishes over the small obstacle.

  Hereinafter, an embodiment of a work machine according to the present invention will be described with reference to FIGS.

(Overall structure of work machine)
As shown in FIG. 1, the work machine 1 of the present example is connected to a lower traveling body 2, an upper revolving body 3 that is turnably mounted on the lower traveling body 2, and a front portion of the upper revolving body 3. Mainly composed of a work front. The upper swing body 3 is driven by a swing motor (not shown). A driver's cab 4 is attached to the upper swing body 3 and a counterweight 8 is provided at a rear portion thereof. The upper swing body 3 is provided with an engine 5, a pump unit 7, and an upper control valve 30 shown in FIG. In the present specification, the upper swing body 3, the cab 4 and the counterweight 8 are collectively referred to as an upper unit 228.

  The work front is pivotally connected at one end to a fulcrum 40 provided at one end of a fulcrum 40 provided at the front of the upper swing body 3 and at a fulcrum 41 provided at the tip of the boom 10. And a bucket 23 having one end pivotably connected to a fulcrum 42 provided at the tip of the arm 12. Between the arm 12 and the bucket 23, a link 17 having one end rotatably connected to the arm 12 and a link 16 having one end rotatably connected to the bucket 23 are rotatably connected. A bent link is provided. The boom 10 is swung in the vertical direction by a boom cylinder 11 having both ends connected to the upper swing body 3 and the boom 10. The arm 12 is swung in the vertical direction by an arm cylinder 13 having both ends connected to the boom 10 and the arm 12. The bucket 23 is swung in the vertical direction by a work tool cylinder 15 having both ends connected to a connecting tent of the arm 12 and the bending link.

  The center frame 201 of the lower traveling body 2 includes a turning angle detector 231 that measures the turning angle of the upper turning body 3 and a biaxial inclination angle sensor that measures the inclination angle of the lower traveling body 2 around the pitch axis and the roll axis. 226. Further, leg units 202a to 202d are provided at the front, rear, left and right ends thereof, and crawler units 229a to 229d are individually attached to the leg units 202a to 202d as an example of a traveling unit. In the following, only the left front leg unit 202a and the crawler unit 229a attached thereto will be described, but the remaining three leg units 202b to 202d and crawler units 229b to 229d are configured similarly. The lower traveling body 2 includes a center frame 201, leg units 202a to 202d, and crawler units 229a to 229d. In addition to the crawler unit, the traveling unit may include a traveling wheel type traveling device (wheel unit).

  The left front leg unit 202a includes a leg base bracket 203a, a leg frame 204a, a leg tip bracket 205a, and a side frame 207a. The leg base bracket 203a is attached to the center frame 201 of the lower traveling body 2 through a fulcrum 208a so as to be swingable up and down. Reference numeral 214a denotes a leg vertical cylinder that swings the leg base bracket 203a up and down, and the leg vertical cylinder 214a is connected to the center frame 201 and the leg base bracket 203a. Reference numeral 230a denotes a leg angle sensor that measures a leg angle defined by the swing rotation angle of the leg frame 204a with respect to the center frame 201.

  The leg end bracket 205a is provided with a side frame 207a that can swing up and down via a fulcrum 213a. No actuator is provided between the leg tip bracket 205a and the side frame 207a, and the side frame 207a swings passively around the fulcrum 213a. Reference numeral 223a denotes a uniaxial inclination angle sensor attached to the side frame 207a. The uniaxial inclination angle sensor 223a is an inclination angle around the pitch axis of the side frame 207a, that is, around the pitch axis of the crawler unit 229. Measure the tilt angle.

  The crawler unit 229a includes an idler 217a that is rotatably provided on the front end side of the side frame 207a, a lower roller 218a that is rotatably provided on the lower side of the side frame 207a, and a rotary that is rotatable on the upper side of the side frame 207a. The upper roller 219a is provided, the drive sprocket 220a is provided on the rear end side of the side frame 207a, and the crawler belt 222a wound around these members. In the crawler unit 229a, the crawler belt 222a rotates around the side frame 207a by causing the driving sprocket 220a to rotate with respect to the side frame 207a by the operation of the traveling hydraulic motor 221a (not shown), thereby causing the work machine 1 to travel. As described above, the side frame 207a is configured to passively swing about the fulcrum 213a, and the crawler unit 229a is attached to the side frame 207a. Therefore, the crawler units 229a to 229a according to the present embodiment. 229d passively rotates according to the shape of the road surface with the fulcrum 213a as a fulcrum.

(Work machine system configuration)
As shown in FIG. 2, the hydraulic system for a work machine according to the present embodiment includes an engine 5, a pump unit 7 including a main pump 70 and a pilot pump 71 driven by the engine 5, and a discharge pipe of the main pump 70. The upper control valve 30 provided in the upper control valve 30, the plurality of upper actuators 26 provided for each actuator oil passage 39 branched from the upper control valve 30, and one of the upper control valve 30 and the actuator oil passage 39. The lower control valve 50 connected, the center joint 6 provided between the upper control valve 30 and the lower control valve 50, and a plurality of lower runnings provided for each actuator oil passage 59 branched from the lower control valve 50. From the body actuator 27 It has been made.

  The sensor system of the lower traveling body 2 changes as the turning angle detector 231 that measures the turning angle of the upper turning body 3 with respect to the center frame 201 and the driving of each leg vertical cylinder 214 other than the traveling hydraulic motor in the actuator 27. A leg angle sensor 230 that measures the leg angle of each leg unit 202 viewed from the center frame 201, a plurality of one-axis tilt angle sensors 223 that measure the tilt angles of the plurality of side frames 207, and the pitch axis of the lower traveling body 2 The sensor includes a biaxial tilt angle sensor 226 that measures the tilt angle around the roll axis, and a pressure sensor 93 that can measure the load pressure of the lower traveling body actuator 27.

  The operation system of the upper actuator 26 includes an operation device 80 for the upper actuator 26 provided in the cab 4 (see FIG. 1), and an electromagnetic valve controller 85 that controls the electromagnetic proportional valve 82 based on a signal from the operation device 80. The electromagnetic proportional controller 82 operates the flow control valve of the upper control valve 30 based on the output current from the electromagnetic valve controller 85.

  The operation / control system of the lower traveling body 2 includes an operating device 81 for the lower traveling body provided in the cab 4 and a communication controller that transmits a signal of the operating device 81 to a control arithmetic controller 92 provided in the lower traveling body 2. 84, a slip ring 87 provided between the communication controller 84 and the control arithmetic controller 92, a control arithmetic controller 92 for calculating upper attitude control described later, and an electromagnetic proportional based on a command signal from the control arithmetic controller 92 An electromagnetic valve controller 86 that controls the valve 83 and an electromagnetic proportional valve 83 that operates the flow control valve of the lower control valve 50 based on the output current from the electromagnetic valve controller 86 are configured.

  The center joint 6 and the slip ring 87 are provided at a connection portion between the upper swing body 3 and the lower traveling body 2. Even when the upper swing body 3 rotates 360 degrees or more with respect to the lower traveling body 2, An electric signal can be transmitted to the lower traveling body 2.

  In the above configuration, the biaxial tilt angle sensor 226 is installed in the center frame 201, but the biaxial tilt angle sensor 226 may be installed in the upper turning unit 3. The biaxial tilt angle measurement result of the upper swing body 3 is obtained by installing the biaxial tilt angle sensor 226 on the center frame 201 based on the swing angle detector 231 that measures the swing angle of the upper swing body 3. It may be converted to be equalized with the measurement result to be used and used for calculation of the upper inclination angle control described later.

(Upper tilt angle control)
Hereinafter, the upper inclination angle control of the work machine according to the embodiment will be described with reference to FIGS. Here, in FIG. 6, the roll angle ψ represents an inclination about the axis of the traveling direction of the center frame 201 with respect to the horizontal plane, and the clockwise direction toward the traveling direction is positive and the counterclockwise direction is negative. The pitch angle φ represents the inclination with respect to the horizontal plane with respect to the axis orthogonal to both the axis of the center frame 201 and the axis of the vertical direction. As shown in FIG. Negative around. Note that the pitch angle φ and the roll angle ψ are expressed with reference to the center frame 201, and do not change even when the upper swing body 3 turns.

FIG. 3 is a flowchart showing a calculation procedure of a drive command to the leg unit 202 performed by the control calculation controller 92 for the upper inclination angle control. After starting the control arithmetic controller 92 (step S301), in step S302, the pitch axis inclination angle φ and the roll axis inclination angle ψ from the biaxial inclination angle sensor 226 and the angle of each leg from the leg angle sensor 230 (FIG. 5). Of θ _LF ^Leg ). Next, in step S303, a later-described upper inclination angle control command calculation for each leg is performed, and a drive command S ^FB (vector) for the leg unit 202 is generated. Further, in step S304, a leg drive limit suppression calculation described later is performed, and the drive command S ^FB is updated to S ^Leg (vector). The leg drive command S ^Leg is output from the electromagnetic valve controller 86 of FIG. 2 to the electromagnetic proportional valve 83 and controls the driving of the leg vertical cylinder 214 via the lower control valve 50. Thereafter, the process proceeds to step S305, and the operations from step S302 to step S304 are repeated.

In the upper tilt angle control command calculation in step S303, the drive commands to the leg units 202a to 202d for controlling the upper tilt angle are calculated by the following equations (1a), (1b), and (1c).

Here, φ _ref and ψ _ref in the formula (1a) are a target pitch inclination angle and a roll inclination angle of the upper unit 228, respectively. Further, the subscripts LF, LR, RF, and RR in the expressions (1b) and (1c) are sequentially associated with the left front, left rear, right front, and right rear leg units 202a to 202d, respectively. Furthermore, each component of K ^FB of formula (1c) (matrix), the pitch angle of inclination deviation for each leg vertical cylinder 214a~214d (φ-φ _ref) that there is a gain for the roll tilt angle error (ψ-ψ _ref) Set a positive value.

Each component of the formula (1b) is a leg lowering operation that widens the vertical interval between the crawler units 229a to 229d and the upper unit 228 when the value is positive, and each crawler unit 229a to 229d and the upper unit 228 when the value is negative. Corresponds to a leg-lifting action that narrows the vertical interval between Further, it is assumed that the target driving speed of each of the crawler units 229a to 229d is increased as the absolute value of each component of the formula (1b) is larger. Although not represented here by the equation, S ^FB obtained by the formula (1a) ~ (1c), as the driving speed when driving the actual leg unit 202a~202d coincides with the target drive velocity It is converted again and sent to step S304. This conversion is based on a database of experimentally measured driving speeds for leg raising and leg lowering obtained under various leg raising and leg lowering command patterns for various upper unit tilt angles and running command conditions. You may refer to the converted version. Hereinafter, the converted command value is expressed as S ^FB .

Each component of K ^FB is set in consideration of the response characteristics of the hydraulic system and the mechanical system of the work machine 1 and may be adjusted experimentally. Further, each component of K ^FB is particularly small when the deviation of the tilt angle is small in consideration of the tilt angle of the upper unit 228, the geometric correspondence between the leg angle and the leg vertical cylinder 214, etc. If the deviation of the angle is large, a particularly large command may be used. For example, the command may be set as a variable according to the leg angle, pitch angle φ, and roll angle ψ. Further, each component of K ^FB may be provided with a dead band in a range of small values such that the tilt angle deviation is not perceivable by the operator. In addition, each component of K ^FB has a maximum value of drive command to each of the leg units 202a to 202d with a slightly smaller value of the deviation of the inclination angle that is sufficient for the operator to feel uneasy. It may be set so that the deviation is larger, or it may be set so that the drive command to each of the leg units 202a to 202d is saturated with the maximum value.

  In the leg drive limit suppression calculation of step S304, when oil is sent to the leg upper and lower cylinders 214a to 214d by the leg drive command of step S303, the leg units 202a to 202d reach the drive limit or do not move in the drive limit state. A leg drive command suppression calculation is performed to avoid a situation in which the cylinder load pressure or the discharge pressure suddenly increases.

Specifically, as shown in Equation 2 below, according to the drive command value s _* ^FB (scalar) obtained in step S303 and the detection result θ _* ^Leg (scalar) of the leg angle sensor 230, FIG. Alternatively, the leg drive command limit gain K ^Leg (s _* ^FB , θ _* ^Leg ) (scalar) determined as shown in FIG. 5 is used as the drive command value s _* ^FB for each leg unit 202a to 202d calculated in step S303. By multiplying, the leg drive command value S _* ^Leg (scalar) of equation (2) is calculated.

S _* ^Leg = K ^Leg (S _* ^FB , θ _* ^Leg ) x S _* ^FB Equation (2)
Thereby, it is possible to suppress a leg drive command that causes the leg unit 202 to reach the drive limit, and to prevent the leg unit 202 from reaching the drive limit.

Here, the leg drive command limit gain K ^Leg (S _* ^FB , θ _* ^Leg ) will be described with reference to FIGS. 4 (a) and 4 (b). When the drive command value S _* ^FB obtained in step S303 is 0 or a positive value, that is, in the case of a leg lowering command, the leg driving command limit gain K ^Leg (S _* ^FB , θ _* ^Leg ) is the leg lowering limit. In the case of the leg angle from the angle θ _LD1 to θ _LD2 , take 0, gradually increase the gain from θ _LD2 to θ _LD3 , and take 1 from θ _LD3 to the leg raising limit angle θ _LU3 Set it. On the other hand, if the drive command value S _* ^FB is a negative value, that is, a leg lift command, the leg drive command limit gain K ^Leg (S _* ^FB , θ _* ^Leg ) is the leg lift limit angle θ _LU3 to θ _LU2. In the case of the angle, 0 is set, the gain is gradually increased from θ _LU2 to θ _LU1 , and _{1 is set} from θ _LU1 to the leg lowering limit angle θ _LD1 . In this way, by setting the leg drive command limit gain K ^Leg (S _* ^FB , θ _* ^Leg ) in accordance with the drive command value S _* ^FB and the detection result θ of the leg angle sensor 230, the drive limit in step S303 is reduced. The leg units 202a to 202d are prevented from reaching the driving limit by suppressing or blocking the close leg raising / lowering driving command.

The above-described θ _LD2 and θ _LU2 are set to values close to θ _LD1 and θ _LU3 within a range in which the drive command value S _* ^FB does not reach θ _LD1 and θ _{LU3 even if the} drive command value S _* ^FB takes the maximum value. In addition, the gain between θ _LD2 and θ _LD3 when the legs are lowered and the gain between θ _LU2 and θ _LU1 when the legs are raised are set so that the leg units 202a to 202d stop smoothly when the drive unit is close to the drive limit angle. The effect to do. Here, θ _LD3 and θ _LU1 are set to values close to θ _LD2 and θ _LU2 in a range where the above-described effect can be obtained. Thereby, it is aimed to suppress the vibration of the structure and the impact force applied when the leg units 202a to 202d stop suddenly at the drive limit angle.

Next, a state where the work machine 1 according to the present embodiment moves uphill from the horizontal road surface 501a through the slope 501b to the upper horizontal road surface 501c will be described with reference to FIGS. In the subsequent control, the target inclination angle is set to be horizontal, that is, φ _ref = ψ _ref = 0 degrees. Further, when the leg angle is taken as in θ _LF ^{Leg in} FIG. 5, the above-mentioned leg raising limit angle θ _{LU3 is set} to 0 degree, and the leg lowering limit angle θ _{LD1 is set} to 60 degrees.

As shown in FIG. 6, when the crawler units 229a and 229b on the front side get on the slope 501b and the upper unit 228 is inclined, the control arithmetic controller 92 follows the flowchart of FIG. The leg unit drive command ^SFB is calculated based on the pitch axis inclination angle φ obtained from (Step S303). At this time, the front leg driving commands S _LF ^FB and S _RF ^FB are negative values, that is, leg raising commands, and the rear leg driving commands S _RF ^FB and S _RR ^FB are positive values, that is, leg lowering commands. Here, in the situation of FIG. 6, since the leg angles of the front legs and the rear legs have a margin of the leg angles with respect to θ _LU2 and θ _{LD2 with} respect to the driving direction, the leg units 202a to 202d in step S304 of FIG. drive command S _* ^Leg is equal to S _* ^FB calculated in step S303 for. Through predetermined calculations and operations in the electromagnetic proportional valve 83 and the lower control valve 50 based on this drive command, the front left and right leg up / down cylinders 214a, 214b perform a leg raising operation, and the rear left / right leg up / down cylinders 214c, 214d perform a leg lowering operation. I do. That is, the upper unit 228 is rotated in the counterclockwise direction (counterclockwise) in FIG. 7 according to the pitch axis inclination angle φ, and the size of the pitch φ is canceled to bring the upper unit 228 into a substantially horizontal state. Control to be. As a result, it is possible to climb while gradually decreasing the pitch axis inclination angle φ, and as shown in FIG. 7, it is possible to climb while the inclination of the upper unit 228 is returned to substantially horizontal. However, in the process of shifting from the state of FIG. 6 to the state of FIG. 7, when the front leg angle reaches θ _LD2 and the drive commands S _LF ^FB and s _RF ^FB to the front leg unit 202 become 0 by the calculation of step S304. In such a situation, the upper inclination angle control is performed only by the rear leg.

  In the process of moving from the slope 501b to the upper horizontal road surface 501c, as shown in FIG. 8, the upper unit 228 is in a state of being pitch-inclined in the opposite direction to that in FIG. 6, but in step S303 in FIG. Since the leg lowering command is calculated for the front leg and the leg raising command is calculated for the rear leg, and all the leg units 202a to 202d have a sufficient leg angle, this drive command is continued as it is and each leg unit 202a to 202d is continued. As shown in FIG. 9, it is possible to drive the upper unit 228 by returning it to a substantially horizontal state.

  As described above, the work machine according to the present embodiment controls the upper and lower leg cylinders 214a to 214d in accordance with the outputs of the leg angle sensor 230 and the biaxial tilt angle sensor 226, whereby the upper unit 228 of the work machine 1 is controlled. Can be automatically set to the target inclination angle.

(Crawler grounding control)
Hereinafter, the crawler grounding control for preventing the crawler from lifting from the road surface will be described with reference to FIGS.

  FIG. 10 is a flowchart showing a calculation procedure of a drive command to the leg units 202a to 202d performed by the control calculation controller 92 for crawler grounding control. As is apparent from FIG. 10, in this example, the crawler grounding control is performed after the calculation of the drive commands to the leg units 202a to 202d (steps S601 to S603) for the upper inclination angle control similar to that shown in FIG. Calculation of drive commands to the leg units 202a to 202d for the purpose (step S604) is performed.

In step S604, a drive command calculation that prompts grounding of each of the crawler units 229a to 229d is performed based on the leg drive command value obtained in step S603 and the cylinder thrust of each of the leg units 202a to 202d described below. In the present embodiment, as means for indirectly detecting the grounding force acting on the crawler units 229a to 229d from the rough road surface necessary for performing the crawler grounding control, the upper and lower sides of the legs that drive the leg units 202a to 202d are used. From the bottom pressure Pb _* and the rod pressure Pr _* acquired by the hydraulic sensor 92 that measures the load pressure of the cylinders 214a to 214d, the cylinder thrust F _* of each leg upper and lower cylinders 214a to 214d calculated by the following equation (3) _: Is used.

F _* = Pb _* × Sb−Pr _* × Sr (3)
In the equation (3), Sb and Sr are the pressure receiving areas on the bottom side and the rod side, respectively, and as shown in FIG. 1, the rod side is swingable to the center frame 201 and the bottom side is swingable to the leg base bracket 203. It is attached. At this time, the cylinder thrust F _* corresponds to a grounded state when the value is positive and to a floating state when the value is negative.

In step S604, the control operation controller 92, a drive command value for the crawler grounding of FIG. 11 which is determined in accordance with the cylinder thrust F _* S _* ^UD (scalar), obtained by the cylinder thrust F _* and step S603 determined the leg drive command as shown in FIGS. 12 and 13 in response to the driving command value s _* ^FB limiter gain ^{_{K c (F *, s *}} FB) drive command value obtained in step S603 (the scalar) s _* By adding the leg drive command multiplied by ^FB , the leg drive command S ^c (scalar) of Equation (4) is calculated.

S ^c = S _* ^UD + K ^c (F _* , S _* ^FB ) × S _* ^FB (Formula 4)
FIG. 11 is a diagram showing a leg lowering command S _* ^UD for crawler contact according to the cylinder thrust F _* . As is apparent from this figure, the work machine of this example determines that the ground contact force acting on the crawler from the rough road surface is weak when the cylinder thrust F _* is less than the set value Ft for each of the leg units 202a to 202d. As the cylinder thrust F _* decreases, the leg lowering command S _* ^UD is gradually increased to the set value Fd. As a result, the crawler that floats or floats from the road surface can be restored to the ground contact state.

Next, the leg thrust command limit gain K ^c (F _* , S _* ^FB ) determined according to the cylinder thrust F _* in FIG. 12 and the leg drive command value S _* ^FB obtained in step S603 in FIG. 11 will be described. To do.

When the leg drive command value S _* ^FB is 0 or a positive value, that is, in the case of a leg lowering command, the leg drive command limit gain K ^c (F _* , S _* ^FB ) is always 1 regardless of the cylinder thrust F. On the other hand, when the leg drive command value S _* ^FB is a negative value, that is, a leg lift command, the leg drive command limit gain K ^c (F _* , S _* ^FB ) is such that the cylinder thrust F _* is Ft = <F _* <= Ft + α. The gain is gradually increased as the cylinder thrust F _* increases in the range of 0, while in the range of Ft + α <F _* <Fu. That is, the leg raising command by the upper inclination angle control command calculation for the leg unit 202 whose cylinder thrust F _* is close to Ft is suppressed. Accordingly, it is possible to suppress the occurrence of hunting by the cylinder thrust F _{* at} the control switching point Ft and the occurrence of chattering of control switching between the crawler grounding control and the upper inclination angle control.

Here, Fd in FIG. 11, and a leg lowering command S _* ^UD between Fd from Ft, FIG 12 alpha value in (b), Fu, and Ft + leg drive command limit gain of between α Fu K ^c (F _* , S _* ^FB ) shall be set so that crawler float does not occur frequently and hunting of cylinder thrust does not occur. The Ft is set to a small value within a range where the crawler grounding state is maintained by the drive command value S _* ^UD . This setting is such that even if the cylinder thrust falls below Ft, the crawler grounding is maintained by the drive command value S _* ^UD , and even when the cylinder thrust F _* is relatively small, the leg raising operation in the upper inclination angle control is executed. Thus, the setting method takes into consideration that the effect of the upper inclination angle control is not hindered.

  Next, using FIG. 13 to FIG. 15, the crawler unit 229a of the work machine 1 for which the crawler grounding control is performed climbs on the small obstacle 801b protruding from the horizontal road surface 801a while moving on the horizontal road surface 801a. I will explain the situation. Here, it is assumed that the center of gravity of the work machine 1 is forward, there is a backlash between the sprocket 220a and the crawler belt 222a in the crawler unit 229a, and the upper unit 228 also has a roll inclination.

  When the left front crawler 229a starts to ride on the small obstacle 801b, the work machine 1 rolls toward the back side of the paper surface. At this time, the work machine 1 performs a leg lowering operation for both the right front and rear legs and a leg raising operation for both the left front and rear legs. Therefore, when the upper inclination angle control is performed but the crawler grounding control is not performed, the inclination angle of the upper unit 228 is substantially horizontal, but the left rear crawler 229c is in a floating state as shown in FIG.

On the other hand, when the crawler grounding control is performed, when the left front crawler 229a gets on the obstacle 801b, the cylinder thrust F _* of the left rear leg unit 202c falls into a state of F _* <Ft. In step S604 of FIG. 10, a leg lowering command corresponding to the weakening of the cylinder thrust is issued as shown in FIG. 11, and the left rear crawler 229c is restored to the ground contact state. Further, when the cylinder thrust F _* is recovered to Ft or more, in step S604, the leg raising command obtained in step S603 is received, but when the cylinder thrust F _* is less than Fu, the gain K in FIG. ^c (F _* , S _* ^FB ) and the formula (4) suppress this leg raising command, so that the left rear crawler 229c actively falls into the floating state by the command obtained in step S603. Suppress. From the above operation, as shown in FIG. 15, the crawler units 229a to 229d are prevented from floating while maintaining the upper inclination angle substantially horizontal, and the obstacle 801b can be overcome while maintaining the ground contact state. It becomes possible.

  As described above, by performing the upper inclination angle control and the crawler grounding control shown in FIG. 10, based on the inclination angle of the upper unit 228 and the ground contact force from the road surface indirectly measured based on the pressure sensor 99. The inclination angle of the upper unit 228 can be automatically made substantially horizontal while keeping the crawler units 229a to 229d in a grounded state.

(Low vehicle height control)
Next, low vehicle height control performed to keep the vehicle height low will be described with reference to FIGS. 16 and 17.

  FIG. 16 is a flowchart showing a calculation procedure of drive commands to the leg units 202a to 202d performed by the control calculation controller 92 for low vehicle height control. As is clear from FIG. 16, in this example, the calculation of the drive command to the leg units 202a to 202d for the upper inclination angle control similar to that shown in FIG. 3 (steps S901 to S903), and FIG. After the calculation of the drive command to the leg units 202a to 202d for the crawler grounding control (steps S904 to S905), the calculation of the drive command to the leg units 202a to 202d for the low vehicle height control (step S906). To S908).

  When the upper inclination angle control shown in FIG. 3 and the crawler contact control shown in FIG. 10 are used, when the work machine 1 gets over the inclined ground shown in FIGS. 5 to 8 and the small obstacle shown in FIGS. Although the unit 228 is kept substantially horizontal, the vehicle height becomes indefinite and a situation may occur in which the vehicle height becomes higher and higher. For example, when only the upper inclination angle control is performed, as is clear from a comparison between FIG. 5 and FIG. 9, the vehicle height that was Ha before climbing is He, and the vehicle height is He after climbing. -Ha increases. This is because when the work machine climbs from the state shown in FIG. 6 to the state shown in FIG. 7, the front leg is not lifted before the drive limit leg angle, so that only the rear leg is lowered to increase the vehicle height. On the other hand, at the stage of reaching FIG. 8, both the front leg and the rear leg are driven, and the leg raising amount of the rear leg at this time is between the state of FIG. 6 and the state of FIG. This is due to being less than the amount of lowering. In this way, when the vehicle height increases with the upper inclination angle control during rough terrain traveling, the center of gravity of the work machine 1 is increased and the entire work machine is destabilized. In addition, the operator feels uneasy / uncomfortable, and a lever operation for lowering the vehicle height is required, resulting in poor workability.

  The low vehicle height control is for preventing the occurrence of such inconvenience, and each of the upper units 228 is controlled so as to keep the vehicle height at a minimum required for the upper inclination angle control. The vertical distances of the crawler units 229a to 229d are obtained indirectly using the leg angle sensor 230, and the leg raising command leg of the four leg units 202a to 202d is selected from the leg lowering command leg according to the flowchart shown in FIG. By driving with priority, the upper inclination angle control is performed.

  Hereinafter, the calculation of the drive command to the leg units 202a to 202d for the low vehicle height control shown in FIG. 16 (steps S906 to S908) will be described. First, in step S906, it is determined whether or not there is a leg raising command leg. If it is determined that there is any leg raising command leg, the process proceeds to step S907, and the upper inclination angle control obtained in step S903 is determined. After the leg raising command leg is driven by the drive command to the leg units 202a to 202d for driving, the process proceeds to step S908 to drive the leg units 202a to 202d for the crawler grounding control obtained in step S904. The leg lowering command leg is driven by the command. If it is determined in step S906 that there is no leg raising command leg, the process proceeds to step S909, and the leg lowering command leg based on the drive command to the leg units 202a to 202d for the upper inclination angle control obtained in step S903. And the leg lowering command leg driving by the driving command to the leg units 202a to 202d for the crawler grounding control obtained in step S904.

  As shown in FIG. 6, when the front crawler units 229a and 229b of the work machine 1 ride on the slope 501b and the upper unit 228 is pitch-inclined, according to the flowchart of FIG. The upper inclination angle control command calculation is performed for each leg unit 202a to 202d. Accordingly, in the process from FIG. 5 to FIG. 7, the crawler units 229a to 229d are always kept in the grounded state, and the command value obtained in step S903 passes through step S904 as it is and proceeds to step S905. If the front leg has a leg allowance for raising the leg in the calculation of step S905, a leg raising command is output, and the process proceeds to step S906 and step S907, and the upper posture is leveled only by the leg raising operation of the front leg. If the front leg has reached the drive limit, the leg raising command is completely suppressed in step S905, and thus the process proceeds from step S906 to step S908, and the upper unit 228 is omitted only by the leg lowering operation based on the posture control of the rear leg. Make it horizontal. With the above operation, the upper unit 228 can be kept substantially horizontal during the traveling of the slope 501b shown in FIG.

  When moving from the inclined surface 501b to the horizontal surface 501c, as shown in FIG. 17, the upper unit 228 is in a state of being pitch inclined in the direction opposite to that in FIG. At this time, in step S903, a leg lowering command for the front leg and a leg raising command for the rear leg are calculated. At this time, since all the crawler units 229a to 229d are grounded and there is a drive margin leg angle, the drive command of step S903 proceeds directly to step S906 through step S904 and step S905. In step S906, since the rear leg is instructed to raise the leg, the process proceeds to step S907, where only the rear leg is raised and the upper unit 228 is leveled. Here, in order to level the upper unit 228 on the horizontal road surface 501c, the rear leg is raised until the leg angle is the same as the leg angle of the front leg. Therefore, as shown in FIG. 18, when the work machine body 1 reaches the horizontal road surface 501c, the upper unit 228 can be made substantially horizontal at the minimum vehicle height.

  As described above, when the above-described low vehicle height control is performed, the work machine 1 is traveling on rough terrain by driving the leg raising command leg preferentially among the upper inclination angle control command values during rough terrain traveling. It is possible to automatically make the posture of the upper unit 228 substantially horizontal while keeping the vehicle height at a minimum required for the upper inclination angle control. As a result, the center of gravity of the work machine 1 can be kept low and stabilized, and the operator's anxiety can be suppressed.

The above-mentioned minimum vehicle height is determined by the drive limit angle of the leg unit 202. However, when the minimum vehicle height is sufficient to prevent the bottom surface of the center frame 201 from coming into contact with the rough road surface. In consideration of the leg angle corresponding to the vehicle height, θ _LU1 , θ _LU2 , θ _LU3 in FIG. 4B may be set. Further, in order to accurately detect the pressure sensor for crawler contact control, from the minimum leg angle that does not reach the stroke end on the leg raising side of each leg vertical cylinder 214, θ _LU1 , θ _LU2 , θ _LU3 may be set.

(Constant height control)
Next, constant vehicle height control performed to keep the vehicle height constant will be described with reference to FIGS.

  According to the low vehicle height control described above, as can be seen from the comparison between FIG. 6 and FIG. 18, the vehicle height after riding over rough terrain is lower than before riding over. However, from the viewpoint of the operator's feeling of operation, a lever operation for adjusting the vehicle height must be performed every time the rider gets over rough terrain, which is complicated.

  The constant vehicle height control eliminates the complexity of lever operation, and detects the vertical distance of each of the crawler units 229a to 229d with respect to the upper unit 228 so as to keep the vehicle height before and after riding over rough terrain as constant as possible. Is indirectly acquired by the leg angle sensor 230, and control according to the flowchart shown in FIG. 19 is performed. It is assumed that the operator can set a desired vehicle height in advance before traveling on rough terrain. This vehicle height is set from the viewpoint of adjusting the field of view and providing a driving margin leg angle in both the direction of raising and lowering the legs so that the cab does not move up and down when overcoming obstacles. Here, the vehicle height set by the operator is referred to as a set vehicle height, and at this time, the leg angle corresponding geometrically is referred to as the set leg angle. When the four leg angles corresponding geometrically do not match, the set leg angle is, for example, the leg angle of the leg unit with the most leg lifted or the average value of the leg angles. Set as a common value for.

  FIG. 19 is a flowchart showing a calculation procedure of drive commands to the leg units 202a to 202d performed by the control calculation controller 92 for constant vehicle height control. As is clear from FIG. 19, in this example, the calculation of the drive command to the leg units 202a to 202d for the upper inclination angle control similar to that shown in FIG. 3 (steps S1101 to S1103), and FIG. After the calculation of the drive command to the leg units 202a to 202d for crawler grounding control (steps S1104 to S1105), the calculation of the drive command to the leg units 202a to 202d for constant vehicle height control (step S1106) To S1113).

  In step S1106, if one or more leg units 202 for which the leg raising command is issued by the upper inclination angle control command calculation in step S1103, even if there is a drive margin leg angle in the leg raising direction up to the set leg angle, The process proceeds from step S1107 to step S1113, and the leg raising command leg in step S1103 and the leg lowering command leg in step S1104 are driven. On the other hand, if there is no corresponding leg raising command leg in step S1106, the process proceeds to step S1108, and if there is a drive margin leg angle in the leg lowering direction up to even one set leg angle, the process proceeds from step S1109 to step S1109. Proceeding to step S1113, the leg lowering command leg in step S1103 and the leg lowering command leg in step S1104 are driven. Further, if there is no corresponding leg lowering leg in step S1108, the process proceeds to step S1110, and if there is any leg raising command leg, the process proceeds from step S1111 to step S1113, and the leg raising command leg in step S1103 is set respectively. The leg lowering command leg in step S1104 is driven. If there is no corresponding leg raising command leg in step S1110, the process proceeds to step S1112 to drive all leg lowering command legs.

The state in which the work machine 1 that has performed constant vehicle height control advances uphill from the lower horizontal road surface 501a to the upper horizontal road surface 501c through the slope 501b will be described with reference to FIGS. 5 to 7, FIG. 17, and FIG. To do. In this example, the vehicle height Ha shown in FIG. 5 is set as the set vehicle height, and the leg angle θ _LF ^Leg shown in FIG. 5 is set as the set leg angle.

  As shown in FIG. 6, when the front crawler units 229a and 229b of the work machine 1 ride on the inclined surface 501b and the upper unit 228 is pitch inclined, according to the flowchart of FIG. Upper tilt angle control command calculation is performed for each leg unit 202a to 202d. At this time, the crawler units 229a to 229d are always kept in a grounded state, and the command value in step S1103 proceeds directly to step S1106. In the situation of FIG. 6, in step S1103, a leg raising command is calculated for the front leg and a leg lowering command is calculated for the rear leg. However, since there is no driving margin leg angle up to the set leg angle, it corresponds to step S1106 and step S1107. Without proceeding to step S1110. Since the leg raising command is output until step S1105 until the leg has a leg raising drive margin, the process proceeds from step S1110 to step S1111 and the upper unit 228 is leveled only by the leg raising operation of the front leg. When the front leg reaches the drive limit, the leg raising command is completely suppressed in step S1105, so the process proceeds from step S1110 to step S1112, and the upper unit 228 is leveled only by the leg lowering operation by the posture control of the rear leg. To do. With the above operation, the upper unit 228 can be kept substantially horizontal during traveling on the slope 501b as shown in FIG.

  When the work machine 1 tries to move from the inclined surface 501b to the horizontal surface 501c, as shown in FIG. 17, the upper unit 228 is in a state of being pitch inclined in the direction opposite to that in FIG. At this time, in step S1103, a leg lowering command for the front leg and a leg raising command for the rear leg are calculated. At this time, since all the crawler units 229a to 229d are grounded and there is a leg drive margin leg angle, the drive command in step S1103 proceeds directly to step S1104 and step S1105, and then proceeds to step S1106. At this time, since the rear leg has a leg raising drive margin leg angle to the set leg angle, the process proceeds from step S1106 to step S1107, and the upper unit 228 is leveled by raising the rear leg only until the set leg angle is reached. Next, when the rear leg reaches the set leg angle, the drive command in step S1103 proceeds to step S1108. At this time, the front leg has a leg lowering margin angle up to the set leg angle, so the process proceeds from step S1108 to step S1109. The leg lowering command leg is driven until the upper unit 228 becomes substantially horizontal. Here, the leg angle of the rear leg on the lower horizontal road surface 501a shown in FIG. 5 and the leg angle of the rear leg on the upper horizontal road surface 501c shown in FIG. When it becomes substantially horizontal on the road surface 501c, the leg angle of the front leg also becomes the set leg angle. That is, the vehicle heights before and after climbing the slope of 501b coincide.

  As described above, when the work machine 1 is controlled at a constant vehicle height, during the rough terrain traveling, the leg unit 202 mainly oriented in the direction of the set leg angle in the upper inclination angle control command calculation is preferentially driven, so that the rough terrain is controlled. It is possible to automatically level the upper unit 228 and keep the vehicle height before and after traveling on rough terrain while keeping the vehicle height during traveling as close to the set vehicle height as possible. Further, when overcoming a convex obstacle lower than the center frame 201 at the set vehicle height on the horizontal road surface, the operator's cab can be overcome naturally without moving up and down the cab. As a result, it is possible to prevent the operator from feeling uncomfortable with the change in the vehicle height and to omit the lever operation necessary for adjusting the vehicle height. Note that after the constant vehicle height control, the vehicle height may include an error with respect to the set vehicle height even though the upper unit is substantially horizontal. In this case, correction control based on the amount of error in the vehicle height may be performed so that the vehicle height is adjusted for each leg unit so that the actual vehicle height matches the set vehicle height.

  When the leg units 202a to 202d are driven in the low vehicle height control and the constant vehicle height control, for example, as shown in step S906, if the leg is not lowered until there is no leg raising command, the upper slope Problems such as the effect of the angle control being weakened or the vehicle body vibrating due to sudden control switching are assumed. Therefore, for example, in the case of step S906 or step S1110, when this branch condition is relaxed and the maximum leg raising command value of the four leg units 202a to 202d falls below a certain value, in addition to the leg raising command leg, It is also possible to start driving the leg-lowering leg weakly. In the constant vehicle height control, for the same reason, after step S1107, it may be set to proceed to step S1108 instead of step S1113. Thereby, the effect of smoothly shifting the driving leg is expected without weakening the effect of the upper inclination angle control. In addition, the low vehicle height control and the constant vehicle height control may allow the operator to select which control mode is appropriate at the time of movement.

(Travel speed control to promote upper tilt angle control)
Next, the traveling speed suppression control for promoting the upper inclination angle control will be described with reference to FIG.

  In the control of each work machine 1 described above, when the unevenness of the rough road surface with respect to the traveling direction is large, the increase amount per unit time of the road surface height difference of each of the crawler units 229a to 229d increases, and the unit time of the upper unit 228 increases. The inclination angle becomes larger. At this time, when the amount of change in the upper inclination angle per unit time due to the uneven terrain is steadily larger than the amount of cancellation of the upper inclination angle per unit time by the above upper inclination angle control, the upper inclination angle Will increase monotonically. Travel speed suppression control to promote upper tilt angle control solves this problem.If the absolute value of the upper tilt angle exceeds a certain value, the current travel speed is suppressed and the unit time due to rough terrain undulations. Keeping the upper inclination angle (and the deviation from the target angle) small by reducing the increase in the upper inclination angle per unit and relatively increasing the cancellation amount of the upper inclination angle per unit time by controlling the upper inclination angle The running speed suppression control that promotes is performed.

Specifically, the travel motor drive command S ^r (vector) calculated by the control operation controller 92 is converted into a travel command S ^o calculated by lever operation related to the travel of the operator as shown in the following equation (5). (Vector) is multiplied by a travel suppression gain K _g ^r (φ, ψ) (scalar) that decreases in accordance with the magnitude of the upper inclination angle obtained from the biaxial inclination angle sensor 226, and is calculated, The traveling speed is suppressed according to the magnitude of the upper inclination angle (φ, ψ).

S ^r = K _g ^r (φ, ψ) × S ^o Formula (5)
21A, 21B, and 21C show examples of correspondence between the upper inclination angle {φ, ψ} and the travel suppression gain K _g ^r (φ, ψ). For example, in FIG. 21A, with respect to the square root value of the square sum of φ and ψ, the gain is set to 1 up to the allowable limit value in the figure, and the gain is set to 0 when the value is equal to or greater than the limit value. As a result, the vehicle travels with the travel command value intended by the operator until the upper limit angle is exceeded as the upper tilt angle increases, and when the upper limit angle is exceeded, the vehicle stops and immediately cancels the upper tilt angle. This makes it possible to keep the upper inclination angle within a certain value.

  However, in FIG. 21A, there is a case where chattering of the travel command occurs near the allowable limit value. Accordingly, as shown in FIG. 21B, a suppression start value smaller than the allowable limit value may be provided, and the gain may be set so as to gradually decrease from the suppression start value to the allowable limit value. At this time, if the upper inclination angle becomes larger and travel suppression starts, the responsiveness of the work machine 1 to the operator's operation of the travel lever is reduced, but the upper inclination angle is kept within a certain value and chattering of the travel command is performed. It becomes possible to suppress.

Here, with the settings shown in FIGS. 21A and 21B, when the upper inclination angle corresponding to the allowable limit value or more is exceeded, the travel command is completely suppressed. However, the operator may want to continue traveling even when the inclination angle of the upper unit 228 is large. Therefore, as shown in FIG. 21 (c), the travel suppression gain may be set to a value larger than 0 even when the speed suppression gain K _g ^r (φ, ψ) is set to the allowable limit value or more.

In addition to the upper inclination angle information, the travel suppression gain may be calculated based on a margin cancellation amount of the upper inclination angle calculated from the drive margin leg angle of each leg unit 202a to 202d. For example, when the margin cancellation amount approaches 0, the travel suppression gains shown in FIGS. 21A, 21B, and 21C are set smaller. Furthermore, the operator may freely switch the setting of the speed suppression gain K _g ^r (φ, ψ) exemplified in FIGS. 21 (a), (b), and (c).

(Travel speed suppression control to promote crawler contact control)
Next, traveling speed suppression control for promoting crawler contact control will be described with reference to FIG.

When the unevenness of the rough road surface with respect to the traveling direction is large, the amount of change per unit time of the road surface height under each of the crawler units 229a to 229d also increases. For this reason, the crawler grounding control is not in time for the crawler floating sign (decrease in the cylinder thrust) caused by the geometrical condition of each leg angle and the road surface height under the crawler, and the crawler floating tends to occur frequently. The traveling speed suppression control for promoting the crawler contact control solves this problem. When the minimum value of the thrust F _* of each leg upper and lower cylinders 214 falls below a certain value, the current traveling speed is controlled by the traveling speed suppression control. By suppressing the speed, the amount of change per unit time in the road surface height under each crawler is reduced, and the effect of the crawler grounding control is relatively increased, thereby maintaining the grounding state of each crawler unit 229. Promote.

  Specifically, the above formula (5) is changed to the following formula (6).

_{^{S r = K c r (min}} (F *)) × K g r (φ, ψ) × So ··· formula (6)
Here, min (F _* ) indicates the minimum value among the cylinder thrusts F _* of the four leg units 202 at the same time.

The corresponding example of the speed reduction gain ^{_{K c r (min (F *}} )) ( scalar) and min (F _*) shown in FIG. 22. As the cylinder thrust is weakened, the crawler contact control is started from Ft. A value smaller than this Ft is set, and from this value, the speed suppression gain is set to gradually decrease toward Fd.

  According to the travel speed suppression control for promoting the crawler contact control, the crawler lift sign is detected by the minimum cylinder thrust, and the travel speed is suppressed to reduce the amount of change per unit time of the road surface under each crawler. Thus, it is possible to relatively promote the effect of the crawler grounding control.

  In each control described so far, if the travel command is large in the first place, the actual leg drive amount is greatly reduced regardless of the leg drive command, for example, by distributing a relatively large amount of hydraulic power to the travel motor. May end up. Therefore, in order to ensure sufficient leg driving even during traveling, the maximum value of the traveling command may be suppressed from the beginning when each of the above controls is performed. Further, when each of the above controls is performed without considering the traveling state, for example, when the vehicle is stopped from the traveling state, the oil that has been flowing to the traveling motor suddenly flows to the leg vertical cylinder 214a, so that the leg units 202a to 202d. May suddenly become faster and the upper unit may vibrate. Therefore, as described above in connection with Equation 1, the leg drive command is corrected based on the drive speed of each leg unit 202a to 202d corresponding to the magnitude of the travel command value that has been databased in advance in the actual machine test. In each control, each leg is driven smoothly regardless of the running / stopped state.

(Upper tilt angle control based on crawler unit tilt angle and horizontal travel speed)
Next, the upper inclination angle control based on the inclination angle of the crawler unit and the horizontal traveling speed will be described with reference to FIGS.

  Each upper inclination angle control after the crawler grounding control described above is feedback control using a deviation itself between the upper inclination angle to be controlled and its target value. Hereinafter, this control is referred to as upper inclination angle feedback control. According to this control, the deviation of the upper inclination angle always occurs in accordance with the undulation of the rough road surface and the leg angles of the leg units 202a to 202d. As described above, the work machine 1 is driven by the hydraulic circuit, but the response of the hydraulic actuator that is the control target is generally low. Therefore, when the work machine 1 is traveling on rough terrain during the upper inclination angle feedback control, unnecessary vibration and behavior of the upper unit 228 may occur due to this control delay, which may cause anxiety and discomfort to the operator. I could give it. The upper inclination angle control based on the inclination angle and the horizontal traveling speed of the crawler unit solves this problem. When the leg unit 202 rides on the uneven road surface, the crawler units 229a to 229d respond to the road surface unevenness. By following the above, the upper tilt angle control is performed by paying attention to the mechanism by which the crawler units 229a to 229d tilt prior to the tilt of the upper unit 228, the control delay described above is alleviated, and unnecessary vibration / behavior of the upper unit 228 is achieved. And the upper inclination angle is maintained at the target value. Furthermore, within the range where the leg angle drive limit angle is not reached, the vehicle height constant control is realized in substantially the same manner.

  Specifically, the inclination angle of each of the crawler units 229a to 229d detected by the uniaxial inclination angle sensor 223 attached to the side frame 207 of each of the crawler units 229a to 229d, and the horizontal progression of each of the left and right crawler units 229a to 229d. Based on the speed, a change amount per unit time of the upper inclination angle is estimated from the current time, and the leg units 202a to 202d are driven so as to cancel the change amount in advance. Hereinafter, this control method is referred to as upper inclination angle feedforward control in order to distinguish it from each upper inclination angle control after the crawler grounding control.

  The upper inclination angle feedforward control logic 1500 shown in FIG. 23 corresponds to a situation in which the terrain is symmetrical with respect to the traveling direction and the obstacle or the depression on the horizontal road surface is climbed over only one of the left and right sides. It is an upper inclination angle feedforward control logic, and is executed by the control arithmetic controller 92 for each control cycle.

  When the system is activated (step S1501), first, predetermined sensor information and operation information from the operator are acquired in step S1502. In step S1503, it is determined whether the vehicle is traveling on rough terrain that is bilaterally symmetric with respect to the traveling direction that is the target of this control logic, or that it is over the obstacle or indentation on the horizontal road surface on one side of the left and right. judge. Here, the traveling determination on the symmetric rough terrain includes the inclination angle of the front two crawler units 229a and 229b, the inclination angle of the rear two crawler units 229c and 229d, the leg angle of the front two legs, and the rear two. It is determined whether the leg angles of the legs are approximately equal to each other, and whether the operator's traveling operation commands are the same on the left and right. Further, whether the left and right side road surfaces are the same horizontal road surface is determined by whether the left and right crawler units 229a and 229c have substantially the same inclination angle and leg angle, or the right and left crawler units. Judgment is made based on whether the inclination angle of 229b and 229d and the leg angle are approximately equal. If it is determined that the road surface is the target, the process proceeds to step S1504. Otherwise, the process proceeds to step S1509. In step S1504, if at least one of the inclination angles of the left and right front crawler units 229a and 229b is substantially horizontal, the process proceeds to step S1505, and if not, the process proceeds to step S1508. In step S1505, if at least one of the left and right front leg angles has a value approximately equal to the previous leg angle, the process proceeds to step S1506. Otherwise, the process proceeds to step S1508. In step S1506, if both the left and right rear crawler units 229c and 229d are substantially horizontal, the process proceeds to step S1508, and if not, the process proceeds to step S1507. In step S1507, the leg drive control described later is performed. In step S1508, front leg drive control is performed, and the process proceeds to step S1509. In step S1509, the process returns to the next control cycle.

The leg drive control in step S1507 will be described. Based on the sensor information acquired in step S1502, the control arithmetic controller 92 detects or estimates later-described horizontal traveling speeds V _{L and} V _R of each of the crawler units 229a to 229d, and the inclination angle θ _LF of each of the crawler units 229a to 229d. ^{_{P, θ LR P, θ RF}} P, to detect the theta _RR ^P. The sign of θ ^P is in the same direction as the pitch angle φ in FIG. At this time, the displacement amount Δh _* of each leg with respect to the vertical direction per unit time is estimated by equations (7a) to (7d).

Δh _LF = V _L × (tan θ _LF ^P ) Equation (7a)
Δh _LR = V _L × (tan θ _LR ^P ) (7b)
Δh _RF = V _R × (tan θ _RF ^P ) Equation (7c)
Δh _RR = V _R × (tan θ _RR ^P ) (7d)
Using this amount of displacement, the leg is driven as follows. Taking the left front leg as an example, the stroke speed of the left front leg up / down cylinder 214 of the left front leg corresponds to the displacement of the fulcrum 213 (the side frame passive axis shown in FIG. 1) Δh _LF per unit time of the left front leg unit 202a. The control arithmetic controller 92 transmits a signal to the solenoid valve controller 86 (and the engine 5) to control the left front leg upper / lower cylinder 214a so that the speed is reached. When Δh _LF is a positive value, a leg raising operation is performed, and when Δh _LF is a negative value, a leg lowering operation is performed. In other words, the stroke of the front leg vertical cylinder 214 is controlled so that the relative displacement amount of the left front crawler unit 229a and the left rear crawler unit 229c per unit time in the vertical direction with respect to the horizontal plane becomes Δh _LF shown in the equation (7a). It becomes. The other leg units 202b to 202d are driven in the same manner. From the above operation, the upper inclination angle is maintained at the target value by driving the leg units 202a to 202d so as to cancel the displacement amount per unit time of the road surface under the crawler units 229a to 229d.

The front leg drive control in step S1508 will be described. The front leg drive control is intended to cancel the displacement amounts Δh _LR and Δh _RR relating to the rear leg described above by driving the front legs. When the left front leg is described as an example, the relative displacement amount Δh _L of the left front and rear legs with respect to the vertical direction per unit time is estimated by the following equation (8).

Δh _L = Δh _LF −Δh _LR = V _L × (tan θ _LF ^P −tan θ _LR ^P ) (8)
Using this amount of displacement, the legs are driven as described above as described above. The control arithmetic controller 92 adjusts the stroke speed of the left front leg vertical cylinder 214a so that the fulcrum 213 (the side frame passive axis shown in FIG. 1) of the left front leg unit 202a is displaced by Δh _L per unit time. A signal is transmitted to the solenoid valve controller 86 (and the engine 5) to control the left front leg vertical cylinder 214a. In other words, the stroke of the front leg upper / lower cylinder 214 is controlled so that the relative displacement of the left front crawler unit 229a per unit time in the vertical direction with respect to the horizontal plane becomes Δh _L shown in Expression (8). The driving of the right front leg is performed in the same manner.

  With the above operation, the upper inclination angle is maintained at the target value by driving the left and right front leg units 202a and 202b so as to cancel the displacement amount per unit time of the road surface below each of the crawler units 229a to 229d.

For the detection or estimation of the horizontal traveling speeds V _{L and} V _R of each of the crawler units 229a to 229d, the rotational angular speed of the engine 5 or the rotational angular speed command value of the engine 5, the low speed / high speed mode information, the low speed / high speed of the traveling motor The current traveling speed may be estimated from a database obtained by previously measuring the traveling speed on the horizontal road surface according to information, lever command value, etc., and the horizontal speed may be estimated from the inclination angle of the track frame. Also, by measuring the load pressure of the travel motor with a pressure sensor and estimating the oil flow rate of the travel motor or attaching a direct flow sensor to the travel motor and acquiring the flow rate to the travel motor, the rotational angular speed of the travel motor And the traveling speed may be estimated.

  FIG. 23 shows a state in which the work machine 1 that has performed the upper inclination angle control based on the inclination angle and the horizontal traveling speed of the crawler unit advances uphill from the lower horizontal road surface 501a to the upper horizontal road surface 501c through the inclined surface 501b. This will be described with reference to FIG. The set vehicle height is set when all the crawler units 229a to 229d are on the lower horizontal road surface 501a and the upper inclination angle is substantially horizontal. The leg angle at this time is set as the set leg angle.

  FIG. 24A shows a situation in which the work machine 1 starts to climb from the horizontal road surface 501a to the slope 501b. The crawler units 229a to 229d are each leg units until the front left and right crawler units 229c and 229d completely ride on the slope 501b after the front left and right crawler units 229a and 229b start to reach the slope 501b from the horizontal road surface 501a. The fulcrum 213 (side frame passive axis) 202a to 202d starts to be inclined uniformly in accordance with the shape of the inclined surface 501b around the rotation center. At this time, since the front and rear crawler units 229 are inclined symmetrically to the left and right, the process proceeds in steps S1501 → 1502 → 1503 → 1504 → 1508 of the upper inclination angle feedforward control logic 1500, and the front leg is controlled by performing the front leg drive control. While raising the legs, keep the upper inclination angle approximately horizontal.

  When the vehicle further travels, all the crawler units 229a to 229d of the work machine 1 are completely on the slope 501b as shown in FIG. At this time, the upper inclination angle feedforward control logic 1500 proceeds in the same manner as before, step S1501 → 1502 → 1503 → 1504 → 1508, but since the inclination angles of the front and rear crawler units 229 are equal, the front leg drive control in step S1508 is expressed by the equation The front leg is not driven by (8). Therefore, it will move forward while maintaining each leg angle, and the upper inclination angle will be kept substantially horizontal.

  When the vehicle further moves forward, the work machine 1 finishes climbing the slope 501b as shown in FIG. At this time, when the front left and right crawler units 229a and 229b start to ride on the horizontal road surface 501c, the inclination angle of the front left and right crawler units 229a and 229b starts to decrease and returns to the horizontal. At this time, the upper inclination angle feedforward control logic 1500 follows the flow of steps S1501 → 1502 → 1503 → 1504 → 1508, and this time the front leg is lowered by the front leg drive control, thereby maintaining the upper inclination angle substantially horizontal. And run.

  When the work machine 1 continues to move forward, the front left and right crawler units 229a and 229b are horizontal, while the rear left and right crawler units 229c and 229d start to ride on the horizontal road surface 501c, and the rear left and right crawler units 229c and 229d are inclined. The angle starts to decrease and converges horizontally. At this time, since the left and right front leg angles have not yet returned to the set leg angle (as shown in FIG. 24C), the left front side frame 207a is returned to the horizontal, but the left front leg unit 202a is smaller than the set leg angle. The upper inclination angle feedforward control logic 1500 follows the flow of steps S1501 → 1502 → 1503 → 1504 → 1505 → 1508, and lowers the front leg by the front leg drive control, thereby the upper inclination angle. Keep the vehicle almost horizontal. When the inclination angles of the rear left and right crawler units 229c and 229d become horizontal, the front left and right leg angles return to the set leg angle.

  Thereafter, when all the crawler units 229a to 229d reach the upper horizontal road surface 501c, all the inclination angles of the crawler units 229a to 229d become substantially horizontal. Therefore, the upper inclination angle feedforward control logic 1500 performs steps S1501 → 1502 → 1503-> 1504-> 1505-> 1506-> 1508, but the front leg drive control in step S1508 does not actually drive the leg unit 202 according to equation (8). The vehicle will move forward with the angle kept substantially horizontal and at the set vehicle height. In the above description, an example of slope climbing has been given as an example of operation on rough terrain that is symmetrical with respect to the traveling direction, but the same operation is performed on other symmetric rough terrain.

  Next, the work machine 1 that has performed the upper inclination angle control based on the inclination angle of the crawler unit and the horizontal traveling speed keeps the obstacle 801b on the horizontal road surface 801a on the left side while keeping the upper inclination angle and the vehicle height constant. A state where only the crawler units 229a and 229c get over will be described with reference to FIGS. 24 and 25 to 28. FIG.

  FIG. 25 shows a situation where the left front crawler unit 229a starts to ride on the obstacle 801b while the work machine 1 moves forward on the horizontal road surface 801a. Further, FIG. 26 shows a situation in which the work machine 1 moves slightly forward from the state of FIG. 25 and the obstacle 801b is located behind the left front crawler unit 229a. In these cases, the upper inclination angle feedforward control logic 1500 follows the flow of steps S1501 → 1502 → 1503 → 1504 → 1505 → 1506 → 1508, and returns to 1501 in the next control cycle in 1509.

  At this time, if the front leg drive control in step S1508 is in the case of FIG. 25, Expression (8) becomes only the change amount of the left front leg crawler unit 229a, and the leg raising operation corresponding to this is performed. Similarly in the case of FIG. 26, only the change amount of the left front leg crawler unit 229a is calculated by the equation (8), and the corresponding leg is lowered. As a result, the upper inclination angle is kept substantially horizontal, and the vehicle height does not change from the set vehicle height.

  27 and 28 show a situation where the left front crawler unit 229a gets over the obstacle 801b, the inclination angle of the left front crawler unit 229a becomes horizontal, and the left rear crawler unit 229c gets over the obstacle 801b. In this case, the upper inclination angle feedforward control logic 1500 follows the flow of steps S1501 → 1502 → 1503 → 1504 → 1505 → 1506 → 1507, and returns to step S1501 in the next control cycle.

At this time, in the leg drive control in step S1507, in the case of FIG. 27, Δh _{LR in} equation (7c) is raised from a positive value according to Δh _LR . In the case of FIG. 28, Δh _LR in equation (7c) is a negative value, and a leg lowering operation is performed according to Δh _LR . When the left rear crawler unit 229c completely passes the obstacle 801b and returns to the horizontal road surface 801a, the left rear leg angle returns to the set leg angle. As a result, the upper inclination angle is kept substantially horizontal, and the vehicle height does not change from the set vehicle height.

  In the above description, the operation of one side of a convex obstacle on the horizontal road surface is shown.However, even in a situation where the vehicle runs on a concave indentation on only one side, the upper inclination angle is kept constant and The height of the cab 4 can be kept constant. However, at this time, the vehicle height does not become constant from the above definition of vehicle height.

  Further, in the leg drive control 1507 in step S1507 and the front leg drive control in step S1508, when the drive margin leg angle of the leg unit 202 to be controlled is lost, the change that the leg unit 202 should originally cancel is described above. The values of Expressions (7a) to (7d) and Expression (8) are corrected so that the amount is covered by driving the remaining leg units 202. Also in the upper inclination angle feedforward control, the upper inclination angle feedback control described above can be used in combination in case the upper inclination angle deviates from the target angle.

  In the embodiment, the case where the crawler units 229a to 229d are used as the traveling units has been described as an example. However, the present invention can also be applied to the case where a running wheel type traveling device is used. In the above embodiment, the case where the four crawler units 229a to 229d are provided has been described as an example, but the present invention can be applied to the case where four or more crawler units are provided.

  1: work machine, 2: lower traveling body, 3: upper turning body, 4: cab, 5: engine, 6: center joint, 7: pump unit, 8: counterweight, 10: boom, 11: boom cylinder, 12: arm, 13: arm cylinder, 15: work tool cylinder, 16: link, 17: link, 23: bucket, 30: upper control valve, 40: fulcrum, 41: fulcrum, 42: fulcrum, 50: lower control valve , 80: operating device (for upper rotating body), 81: operating device (for lower traveling body), 82: electromagnetic proportional valve (for upper rotating body), 83: electromagnetic proportional valve (for lower traveling body), 84: communication 85: Solenoid valve controller (for upper swing body), 86: Solenoid valve controller (for lower traveling body), 87: Slip ring, 92: Control arithmetic controller, 20 : Center frame, 202a, 202b, 202c, 202d: leg unit, 203a: leg base bracket, 204a: leg frame, 205a: leg tip bracket, 207a: side frame, 208a: fulcrum (center frame-base bracket), 213a : Fulcrum (side frame passive shaft), 214a: leg vertical cylinder, 217a: idler, 218a: lower roller, 219a: upper roller, 220a: drive sprocket, 222a: crawler belt, 223a: 1-axis tilt angle sensor, 226: 2-axis Tilt angle sensor, 228: upper unit, 229a: crawler unit, 229c: crawler unit, 230a: leg angle sensor, 231: turning angle detector, 300: drive command to leg unit 202 performed for upper tilt angle control Calculation flowchart 303: Upper inclination angle control command calculation, 304: Leg drive limit suppression calculation, 501a: Horizontal road surface, 501b: Slope, 501c: Horizontal road surface, 600: Drive command calculation flowchart of each leg unit in upper inclination angle control and crawler grounding control 603: Upper inclination angle control command calculation, 604: Crawler contact control command calculation, 605: Leg drive limit suppression calculation, 801a: Horizontal road surface 503, 801b: Small obstacle, 900: Low vehicle height flowchart, 1100: Constant vehicle height Flowchart 1500: Upper tilt angle feedforward control logic.

Claims (8)

An upper unit having a driver's cab and a work front; four or more leg units, one end of which is connected to the upper unit and swinging within a predetermined swing angle; and at least each leg unit supported In a work machine having four or more traveling units and a controller that controls driving of each leg unit and each traveling unit,
When the controller travels on rough terrain, the tilt angle of the upper unit is maintained within a preset threshold with respect to a preset target tilt angle, and each of the travel units and the road surface of the rough terrain In order to maintain the ground contact state, the leg unit is given a drive command for leg raising drive or leg lowering drive within a range in which the swing angle of each leg unit does not exceed the predetermined swing angle. A work machine characterized by output.   And an upper unit inclination angle detecting means for detecting an inclination angle of the upper unit, wherein the controller has an inclination angle of the upper unit detected by the upper unit inclination angle detecting means within the threshold with respect to the target inclination angle. 2. The leg raising drive or the leg lowering drive of each leg unit is feedback-controlled so that the ground contact state between the running unit and the rough road surface is maintained. Working machine.   It further comprises a contact force detecting means for detecting or estimating a contact force acting on each traveling unit from the road surface of the rough terrain, and the controller acts on each traveling unit detected by each contact force detecting means. The leg lowering drive of each leg unit is controlled so that the grounding force to be applied is stronger than a first grounding force threshold value set in advance. Working machine.   Vertical distance detection means for detecting the vertical distance of each travel unit relative to the upper unit is further provided, and the controller is detected by the vertical distance detection means, and is a maximum value of the vertical distances of the travel units. The defined vehicle height is the minimum within a range in which the inclination angle of the upper unit is maintained within the threshold with respect to the target inclination angle, and the ground contact state between the traveling units and the road surface of rough terrain is maintained. The work machine according to any one of claims 1 to 3, wherein a leg raising drive or a leg lowering drive of each leg unit is controlled.   Vertical distance detection means for detecting the vertical distance of each travel unit relative to the upper unit is further provided, and the controller is detected by the vertical distance detection means, and is a maximum value of the vertical distances of the travel units. The leg raising drive or leg lowering drive of each leg unit is controlled so that a defined vehicle height becomes a preset target vehicle height. The working machine described in.   The controller is output to each traveling unit when a deviation between the inclination angle of the upper unit detected by the upper unit inclination angle detecting means and the target inclination angle is equal to or larger than a preset inclination angle threshold. The work machine according to any one of claims 2 to 5, wherein a travel speed command is suppressed more than when the deviation is equal to or less than the inclination angle threshold value.   The controller outputs to each traveling unit when any of the grounding forces acting on each traveling unit detected by the respective grounding force detecting means becomes equal to or less than a second grounding force threshold value set in advance. 6. The driving speed command is suppressed more than when the grounding force acting on each of the traveling units is greater than or equal to the second grounding force threshold value. 6. The working machine described in.   Traveling unit inclination angle detecting means for detecting an inclination angle of each traveling unit; and horizontal traveling speed detecting means for detecting or estimating a horizontal traveling speed of each traveling unit; and the controller further comprising: From the inclination angle of the traveling unit detected by the detecting means and the horizontal traveling speed of the traveling unit detected by the horizontal traveling speed detecting means, the amount of change in the vertical direction per unit time of each traveling unit is estimated. The work machine according to any one of claims 1 to 7, wherein the leg raising drive or the leg lowering drive of each leg unit is feedforward controlled so as to cancel the amount of change.

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