Patent Description:
A loading machine is used at a work site. <CIT> discloses an example of an automatic excavator including a measuring instrument for obtaining a distance to an excavation target and a loading target.

<CIT> discloses a rotation type working machine and a control method for the rotation type working machine that stops the rotation when the height of a bucket of the rotation type working machine is lower than the height of a dump truck. <CIT> discloses the features of the preambles of claims <NUM> and <NUM>. <CIT> discloses a control unit for a working machine that reduces the turning speed when it is determined that a contact between a work implement of the working machine and a transport vehicle could occur. <CIT> discloses the features of the preambles of claims <NUM> and <NUM>.

In a case where automation of loading work by a loading machine is to be achieved, a technique capable of favorably measuring relative positions of the loading machine and a loading target is required.

An object of an aspect of the present invention is to favorably measure relative positions of a loading machine and a loading target.

According to an aspect of the present invention, a loading machine control device comprises: a measurement data acquisition unit that acquires measurement data of a measurement device mounted in a loading machine that has working equipment; a target calculation unit that calculates, on the basis of the measurement data, a position of an upper end portion of a loading target to which an excavation object excavated by a bucket of the working equipment is loaded; a bucket calculation unit that calculates position data of the bucket; an overlap determination unit that determines whether or not the upper end portion of the loading target and the bucket that are in the measurement data overlap each other; a working equipment control unit that controls the working equipment on the basis of the measured position of the upper end portion of the loading target when it is determined that the upper end portion of the loading target and the bucket that are in the measurement data do not overlap each other; and wherein the overlap determination unit determines whether or not there is overlap on the basis of relative positions of the measurement device, the upper end portion of the loading target, and the bucket, and wherein the bucket calculation unit calculates a position of a lower end portion of the bucket, and the target calculation unit calculates the position of the upper end portion of the loading target when an angle specified on the basis of the measurement device, the upper end portion of the loading target, and the lower end portion of the bucket is equal to or larger than a predetermined angle.

Preferred embodiments of the loading machine control device are defined in dependent claims <NUM> to <NUM>.

According to a further aspect of the present invention, a loading machine control method is defined in independent method claim <NUM>.

According to an aspect of the present invention, it is possible to favorably measure relative positions of a loading machine and a loading target.

Components of the embodiments that will be described below may be combined as appropriate. Furthermore, there may be a case where a part of the components is not used.

<FIG> is a side view illustrating an example of a loading machine <NUM> according to the present embodiment. The loading machine <NUM> performs predetermined work at a work site. In the present embodiment, the loading machine <NUM> is assumed to be a wheel loader <NUM> that is a kind of an articulated loading machine. The predetermined work includes excavation work and loading work. A work target includes an excavation target and a loading target. The wheel loader <NUM> performs excavation work for excavating the excavation target and loading work for loading an excavation object excavated by the excavation work to the loading target. Concept of the loading work includes discharging work for discharging an excavation object to a discharging target. As the excavation target, at least one of a rock mass, a rock heap, coal, or a wall surface is exemplified. The rock mass is a heap including sediment. The rock heap is a heap including rock or stone. As the loading target, at least one of a transportation vehicle, a predetermined area of the work site, a hopper, a belt conveyor, or a crusher is exemplified.

As illustrated in <FIG>, the wheel loader <NUM> includes a vehicle body <NUM>, a cab <NUM> provided with a driver seat, a travel device <NUM> that supports the vehicle body <NUM>, working equipment <NUM> supported by the vehicle body <NUM>, an angle sensor <NUM> that detects an angle of the working equipment <NUM>, a transmission device <NUM>, a three-dimensional measurement device <NUM> that measures a measurement target ahead of the vehicle body <NUM>, and a control device <NUM>.

The vehicle body <NUM> includes a vehicle body front part 2F and a vehicle body rear part 2R. The vehicle body front part 2F and the vehicle body rear part 2R are bendably coupled via a joint mechanism <NUM>.

The cab <NUM> is supported by the vehicle body <NUM>. At least a part of the wheel loader <NUM> is operated by a driver on the cab <NUM>.

The travel device <NUM> supports the vehicle body <NUM>. The travel device <NUM> has wheels <NUM>. The wheels <NUM> rotate by driving force generated by an engine mounted in the vehicle body <NUM>. Tires <NUM> are fitted on the wheels <NUM>. The wheels <NUM> include two front wheels 5F fitted on the vehicle body front part 2F and two rear wheels 5R fitted on the vehicle body rear part 2R. The tires <NUM> include front tires 6F fitted on the front wheels 5F and rear tires 6R fitted on the rear wheels 5R. The travel device <NUM> can travel on ground RS.

The front wheels 5F and the front tires 6F are rotatable around a rotation shaft FX. The rear wheels 5R and the rear tires 6R are rotatable around a rotation shaft RX.

In the following description, a direction parallel to the rotation shaft FX of the front wheels 5F is referred to as a vehicle width direction as appropriate, a direction orthogonal to a ground contact surface of the front tires 6F, which contacts the ground RS, is referred to as a vertical direction as appropriate, and a direction orthogonal to both the vehicle width direction and the vertical direction is referred to as a front-back direction as appropriate. When the vehicle body <NUM> of the wheel loader <NUM> travels straight, the rotation shaft FX and the rotation shaft RX are parallel to each other.

The travel device <NUM> has a drive device 4A, a brake device 4B, and a steering device 4C. The drive device 4A generates driving force for accelerating the wheel loader <NUM>. The drive device 4A includes an internal combustion engine such as a diesel engine. The driving force generated by the drive device 4A is transmitted to the wheels <NUM> via the transmission device <NUM>, and the wheels <NUM> rotate. The brake device 4B generates braking force for decelerating or stopping the wheel loader <NUM>. The steering device 4C can adjust a travel direction of the wheel loader <NUM>. The travel direction of the wheel loader <NUM> includes orientation of the vehicle body front part 2F. The steering device 4C adjusts the travel direction of the wheel loader <NUM> by bending the vehicle body front part 2F with a hydraulic cylinder.

In the present embodiment, the travel device <NUM> is operated by the driver on the cab <NUM>. The working equipment <NUM> is controlled by the control device <NUM>. A travel operation device <NUM> for operating the travel device <NUM> is placed on the cab <NUM>. The driver operates the travel operation device <NUM> to activate the travel device <NUM>. The travel operation device <NUM> includes an accelerator pedal, a brake pedal, a steering lever, and a shift lever <NUM> that is for switching between forward and backward movement. By the accelerator pedal being operated, travel speed of the wheel loader <NUM> increases. By the brake pedal being operated, travel speed of the wheel loader <NUM> decreases or travel is stopped. By the steering lever being operated, the wheel loader <NUM> swings. By the shift lever <NUM> being operated, forward movement or backward movement of the wheel loader <NUM> is switched.

The transmission device <NUM> transmits the driving force generated in the drive device 4A to the wheels <NUM>.

The working equipment <NUM> has a boom <NUM> rotatably coupled to the vehicle body front part 2F, and a bucket <NUM>, a bell crank <NUM>, and a link <NUM> that are rotatably coupled to the boom <NUM>.

The boom <NUM> is activated by power generated by a boom cylinder <NUM>. By the boom cylinder <NUM> extends and contracts, the boom <NUM> performs rising motion or falling motion.

The bucket <NUM> is a work member having a tip portion 12B including a cutting edge. The bucket <NUM> is placed ahead of the front wheels 5F. The bucket <NUM> is coupled to a tip portion of the boom <NUM>. The bucket <NUM> is activated by power generated by a bucket cylinder <NUM>. By the bucket cylinder <NUM> extends and contracts, the bucket <NUM> performs dumping motion or tilting motion.

By dumping motion by the bucket <NUM> is performed, an excavation object scooped up by the bucket <NUM> is discharged from the bucket <NUM>. By tilting motion by the bucket <NUM> is performed, the bucket <NUM> scoops an excavation object.

The angle sensor <NUM> detects an angle of the working equipment <NUM>. The angle sensor <NUM> includes a boom angle sensor <NUM> that detects an angle of the boom <NUM> and a bucket angle sensor <NUM> that detects an angle of the bucket <NUM>. The boom angle sensor <NUM> detects an angle of the boom <NUM> with respect to a reference axis of a vehicle body coordinate system specified to the vehicle body front part 2F, for example. The bucket angle sensor <NUM> detects an angle of the bucket <NUM> with respect to the boom <NUM>. The angle sensor <NUM> may be a potentiometer or a stroke sensor that detects stroke of the hydraulic cylinder.

The three-dimensional measurement device <NUM> is mounted in the wheel loader <NUM>. The three-dimensional measurement device <NUM> is supported by a housing <NUM>. The three-dimensional measurement device <NUM> measures a measurement target ahead of the vehicle body front part 2F. The measurement target includes a loading target in which an excavation object excavated by the working equipment <NUM> is loaded. The three-dimensional measurement device <NUM> measures a three-dimensional shape of the measurement target. The three-dimensional measurement device <NUM> measures relative positions from the three-dimensional measurement device <NUM> to each of a plurality of measurement points on a surface of the measurement target, and measures a three-dimensional shape of the measurement target. The control device <NUM> calculates a parameter related to the loading target on the basis of the measured three-dimensional shape of the loading target. The parameter related to the loading target includes at least one of a distance to the loading target, a position of an upper end portion of the loading target, and height of the loading target.

Relative positions of the wheel loader <NUM> and the measurement target include relative distances (three-dimensional distances) between the wheel loader <NUM> and the measurement target. The three-dimensional measurement device <NUM> can measure a three-dimensional shape of the measurement target and relative positions with the measurement target by measuring distances to each of the plurality of measurement points on the surface of the measurement target.

The three-dimensional measurement device <NUM> includes a laser radar <NUM> that is a kind of a laser measurement device and a stereo camera <NUM> that is a kind of a photographic measurement device.

Measurement data acquired by the laser radar <NUM> is output to the control device <NUM>. The control device <NUM> measures a three-dimensional shape of the measurement target on the basis of the measurement data by the laser radar <NUM>.

The stereo camera <NUM> images the measurement target and measures the measurement target. The stereo camera <NUM> has a first camera 22A and a second camera 22B. Image data acquired by the first camera 22A and image data acquired by the second camera 22B are output to the control device <NUM>. The control device <NUM> performs stereo processing on the basis of the image data acquired by the first camera 22A and the image data acquired by the second camera 22B, and measures a three-dimensional shape of the measurement target. The image data is an example of measurement data.

<FIG> is a schematic diagram illustrating motion of the wheel loader <NUM> according to the present embodiment. The wheel loader <NUM> works in a plurality of work modes. The work modes include an excavation work mode in which the bucket <NUM> of the working equipment <NUM> excavates an excavation target, and a loading work mode in which the excavation object scooped by the bucket <NUM> in the excavation work mode is loaded to the loading target. As the excavation target, a rock mass DS placed on the ground RS is exemplified. As the loading target, a vessel BE of a transportation vehicle LS capable of traveling on ground is exemplified. As the transportation vehicle LS, a dump truck is exemplified.

In the excavation work mode, the wheel loader <NUM> moves forward toward the rock mass DS in order to excavate the rock mass DS with the bucket <NUM> of the working equipment <NUM> in a state where no excavation object is held in the bucket <NUM> of the working equipment <NUM>. A driver of the wheel loader <NUM> operates the travel operation device <NUM> to move the wheel loader <NUM> forward to approach the rock mass DS, as indicated by an arrow M1 in <FIG>. The control device <NUM> controls the working equipment <NUM> so that the rock mass DS is excavated by the bucket <NUM>.

After the rock mass DS is excavated by the bucket <NUM> and the excavation object is scooped by the bucket <NUM>, the wheel loader <NUM> moves backward to be separated from the rock mass DS in a state where the excavation object is held in the bucket <NUM> of the working equipment <NUM>. The driver of the wheel loader <NUM> operates the travel operation device <NUM> to move the wheel loader <NUM> backward to be away from the rock mass DS, as indicated by an arrow M2 in <FIG>.

Next, the loading work mode is performed. In the loading work mode, the wheel loader <NUM> moves forward toward the transportation vehicle LS in order to load the excavation object excavated by the bucket <NUM> of the working equipment <NUM> in a state where the excavation object is held in the bucket <NUM> of the working equipment <NUM>. The driver of the wheel loader <NUM> operates the travel operation device <NUM> to move the wheel loader <NUM> forward, while swinging the wheel loader <NUM>, to approach the transportation vehicle LS, as indicated by an arrow M3 in <FIG>. The three-dimensional measurement device <NUM> mounted in the wheel loader <NUM> measures the transportation vehicle LS. The control device <NUM> controls the working equipment <NUM> on the basis of the measurement data in the three-dimensional measurement device <NUM> so that the excavation object held by the bucket <NUM> is loaded to the vessel BE of the transportation vehicle LS. That is, the control device <NUM> controls the working equipment <NUM> so that the boom <NUM> performs rising motion in a state where the wheel loader <NUM> is moving forward so as to approach the transportation vehicle LS. After the boom <NUM> performs rising motion and the bucket <NUM> is placed above the vessel BE, the control device <NUM> controls the working equipment <NUM> so that the bucket <NUM> performs tilting motion. With this arrangement, the excavation object is discharged from the bucket <NUM> and loaded to the vessel BE.

After the excavation object is discharged from the bucket <NUM> and loaded to the vessel BE, the wheel loader <NUM> moves backward to be separated from the transportation vehicle LS in a state where no excavation object is held in the bucket <NUM> of the working equipment <NUM>. The driver operates the travel operation device <NUM> to move the wheel loader <NUM> backward to be away from the transportation vehicle LS, as indicated by an arrow M4 in <FIG>.

The driver and the control device <NUM> repeat the above-described motion until the vessel BE is fully loaded with an excavation object.

<FIG> is a schematic diagram illustrating the loading work mode of the wheel loader <NUM> according to the present embodiment. The driver of the wheel loader <NUM> operates the travel operation device <NUM> to move the wheel loader <NUM> forward to approach the transportation vehicle LS. As illustrated in <FIG>, the three-dimensional measurement device <NUM> mounted in the wheel loader <NUM> measures a three-dimensional shape of the transportation vehicle LS. The control device <NUM> detects a distance between the wheel loader <NUM> and the transportation vehicle LS and height of an upper end portion of the vessel BE on the basis of the measurement data in the three-dimensional measurement device <NUM>. The distance from the wheel loader <NUM> to the transportation vehicle LS includes a distance from the tip portion 12B of the bucket <NUM> to the transportation vehicle LS, a distance from any point of the bucket <NUM> to the transportation vehicle LS, a distance from any point of a main body of the wheel loader <NUM> to the transportation vehicle LS, and a distance from the three-dimensional measurement device <NUM> to the transportation vehicle LS. The distance from the tip portion 12B of the bucket <NUM> includes a distance from a central portion of the tip portion 12B and a distance from any one point of both ends of the tip portion 12B. The distance from the wheel loader <NUM> to the transportation vehicle LS includes a distance extending from the tip portion 12B of the bucket <NUM> in a traveling direction of the vehicle body front part 2F to a point crossing the transportation vehicle LS, and a shortest distance from the tip portion 12B of the bucket <NUM> to the transportation vehicle LS. The distance from the wheel loader <NUM> to the transportation vehicle LS includes a horizontal distance and a distance in a direction parallel to the ground RS. Furthermore, the distance to the transportation vehicle LS includes a distance to a closest point of the transportation vehicle LS, that is, a point closest on a wheel loader <NUM> side of the transportation vehicle LS.

As illustrated in <FIG>, in a state where the wheel loader <NUM> is moving forward to approach the transportation vehicle LS, the control device <NUM>, on the basis of the measurement data in the three-dimensional measurement device <NUM>, causes the boom <NUM> to perform rising motion, by controlling an angle of the bucket <NUM> so that the bucket <NUM> is placed above the upper end portion of the vessel BE and that the excavation object held by the bucket <NUM> does not spill out of the bucket <NUM>.

As illustrated in <FIG>, after the boom <NUM> performs rising motion and the bucket <NUM> is placed above the vessel BE, the control device <NUM> controls the working equipment <NUM> so that the bucket <NUM> performs tilting motion. With this arrangement, the excavation object is discharged from the bucket <NUM> and loaded to the vessel BE.

<FIG> is a functional block diagram illustrating the control device <NUM> of the wheel loader <NUM> according to the present embodiment. The control device <NUM> includes a computer system.

The working equipment <NUM>, the transmission device <NUM>, the travel device <NUM>, the three-dimensional measurement device <NUM>, the angle sensor <NUM>, and the travel operation device <NUM> are connected to the control device <NUM>.

The control device <NUM> has a measurement data acquisition unit <NUM>, a storage unit <NUM>, a bucket calculation unit <NUM>, a target calculation unit <NUM>, an overlap determination unit <NUM>, and a working equipment control unit <NUM>.

The measurement data acquisition unit <NUM> acquires measurement data in the three-dimensional measurement device <NUM> from the three-dimensional measurement device <NUM>. The three-dimensional measurement device <NUM> outputs the measurement data to the control device <NUM>.

Furthermore, the storage unit <NUM> stores working equipment data. The working equipment data includes design data or specification data of the working equipment <NUM>. The design data of the working equipment <NUM> includes, for example, computer aided design (CAD) data of the working equipment <NUM>. The working equipment data includes outer shape data of the working equipment <NUM>. The outer shape data of the working equipment <NUM> includes dimension data of the working equipment <NUM>. In the present embodiment, the working equipment data includes data of boom length, bucket length, and an outer shape of the bucket. The boom length refers to a distance between a boom rotation shaft and a bucket rotation shaft. The bucket length refers to a distance between the bucket rotation shaft and the tip portion 12B of the bucket <NUM>. The boom rotation shaft refers to a rotation shaft of the boom <NUM> with respect to the vehicle body front part 2F, and includes a coupling pin that couples the vehicle body front part 2F and the boom <NUM>. The bucket rotation shaft refers to a rotation shaft of the bucket <NUM> with respect to the boom <NUM>, and includes a coupling pin that couples the boom <NUM> and the bucket <NUM>. The outer shape of the bucket includes a shape and dimensions of the bucket <NUM>. The dimensions of the bucket <NUM> include a bucket width that indicates a distance between a left end and a right end of the bucket <NUM>, height of an opening of the bucket <NUM>, length of a bottom surface of the bucket, and the like.

The bucket calculation unit <NUM> calculates position data of the working equipment <NUM> on the basis of angle data of the working equipment <NUM> detected by the angle sensor <NUM> and the working equipment data of the working equipment <NUM>, the working equipment data being stored in the storage unit <NUM>. The bucket calculation unit <NUM> calculates position data of the bucket <NUM> in a vehicle body coordinate system, for example. The bucket calculation unit <NUM> calculates at least a position of the tip portion 12B of the bucket <NUM> and a position and height of a lower end portion 12E of the bucket <NUM>.

On the basis of the measurement data acquired by the measurement data acquisition unit <NUM>, the target calculation unit <NUM> calculates three-dimensional data of the transportation vehicle LS including the vessel BE, three-dimensional data being measured by the three-dimensional measurement device <NUM>. The three-dimensional data of the transportation vehicle LS indicates a three-dimensional shape of the transportation vehicle LS.

The target calculation unit <NUM> calculates a parameter related to the transportation vehicle LS on the basis of the three-dimensional data of the transportation vehicle LS. The parameter related to the transportation vehicle LS includes at least one of the distance from the wheel loader <NUM> to the transportation vehicle LS and height of an upper end portion BEt of the vessel BE. The height of the upper end portion BEt of the vessel BE is an example of the position of the upper end portion of the loading target, the height of the loading target, a position of the upper end portion of the transportation vehicle LS, and height of the transportation vehicle LS.

The overlap determination unit <NUM> determines whether or not the upper end portion BEt of the vessel BE and the bucket <NUM> overlap each other in the measurement data.

On the basis of relative positions of a position of the three-dimensional measurement device <NUM>, a position of the upper end portion BEt of the vessel BE, and the bucket <NUM>, the overlap determination unit <NUM> determines whether or not the upper end portion BEt of the vessel BE and the bucket <NUM> overlap each other.

When it is determined in the overlap determination unit <NUM> that the upper end portion BEt of the vessel BE and the bucket <NUM> do not overlap each other, the target calculation unit <NUM> calculates the height of the upper end portion BEt of the vessel BE.

In the present embodiment, the bucket calculation unit <NUM> calculates a position of the bucket <NUM> in a vehicle body coordinate system of the wheel loader <NUM>. When an angle specified on the basis of the position of the three-dimensional measurement device <NUM>, a position of the upper end portion BEt of the vessel BE, and a position of a lower end portion of the bucket <NUM> is equal to or larger than a predetermined angle, the target calculation unit <NUM> calculates the position of the upper end portion BEt of the vessel BE.

On the basis of the distance to the transportation vehicle LS and height of the upper end portion BEt of the vessel BE that are calculated by the target calculation unit <NUM>, the working equipment control unit <NUM> controls motion of the working equipment <NUM> for loading the excavation object to the vessel BE. When it is determined in the overlap determination unit <NUM> that the upper end portion BEt of the vessel BE and the bucket <NUM> do not overlap each other, the working equipment control unit <NUM> calculates the working equipment <NUM> on the basis of the position of the upper end portion BEt of the vessel BE.

Control of motion of the working equipment <NUM> includes control of motion of at least one of the boom cylinder <NUM> and the bucket cylinder <NUM>. The wheel loader <NUM> has a hydraulic pump, a boom control valve that controls a flow rate and direction of hydraulic oil supplied from the hydraulic pump to the boom cylinder <NUM>, and a bucket control valve that controls a flow rate and direction of hydraulic oil supplied from the hydraulic pump to the bucket cylinder <NUM>. The working equipment control unit <NUM> can output a control signal to the boom control valve and the bucket control valve, control the flow rate and direction of the hydraulic oil supplied to the boom cylinder <NUM> and the bucket cylinder <NUM>, and control rising/falling motion of the boom <NUM> and rising/falling motion of the bucket <NUM>.

In the present embodiment, the target calculation unit <NUM> removes partial data that indicates at least a part of the working equipment <NUM> from the measurement data on the basis of the position data of the working equipment <NUM> calculated by the bucket calculation unit <NUM>, and calculates the height data of the upper end portion BEt of the vessel BE and distance data to the transportation vehicle LS on the basis of the measurement data from which the partial data is removed.

In the present embodiment, the wheel loader <NUM> has a transmission control unit <NUM> and a travel control unit <NUM>.

The transmission control unit <NUM> controls motion of the transmission device <NUM> on the basis of operation of the travel operation device <NUM> by the driver of the wheel loader <NUM>. Control of motion of the transmission device <NUM> includes control of a shift change.

The travel control unit <NUM> controls motion of the travel device <NUM> on the basis of operation of the travel operation device <NUM> by the driver of the wheel loader <NUM>. The travel control unit <NUM> outputs an operation command including an acceleration command for activating the drive device 4A, a brake command for activating the brake device 4B, and a steering command for activating the steering device 4C.

In the present embodiment, on the basis of a position of the upper end portion of the vessel BE calculated by the target calculation unit <NUM> and the position of the lower end portion of the bucket <NUM> calculated by the bucket calculation unit <NUM>, the working equipment control unit <NUM> determines whether or not relative positions of the upper end portion of the vessel BE and the lower end portion of the bucket <NUM> satisfy a specified condition.

<FIG>, <FIG>, and <FIG> are diagrams illustrating a measurement range in the stereo camera <NUM> as an example of a measurement range AR of the three-dimensional measurement device <NUM>. When measuring a measurement target by using the three-dimensional measurement device <NUM>, there is a possibility that at least a part of the working equipment <NUM> is placed within the measurement range AR of the three-dimensional measurement device <NUM>. In a case where the three-dimensional measurement device <NUM> is the stereo camera <NUM>, a measurement range of the three-dimensional measurement device <NUM> includes an imaging range of the stereo camera <NUM> (a field of view of an optical system of the stereo camera <NUM>). In a case where the three-dimensional measurement device <NUM> is the laser radar <NUM>, the measurement range of the three-dimensional measurement device <NUM> includes an irradiation range of laser light emitted from the laser radar <NUM>.

The specified condition includes a condition in which the upper end portion of the vessel BE is placed within the measurement range AR of the three-dimensional measurement device <NUM> without being blocked by the bucket <NUM> of the working equipment <NUM>.

<FIG> illustrates an example in which the bucket <NUM> is placed within the measurement range AR of the three-dimensional measurement device <NUM>, and the lower end portion 12E of the bucket <NUM> is placed below the upper end portion of the vessel BE. As illustrated in <FIG>, there may be a case where the upper end portion of the vessel BE is hidden by the bucket <NUM> depending on relative positions of the upper end portion of the vessel BE and the lower end portion 12E of the bucket <NUM>.

<FIG> illustrates an example in which the lower end portion 12E of the bucket <NUM> is placed above the upper end portion of the vessel BE although the bucket <NUM> is placed within the measurement range AR of the three-dimensional measurement device <NUM>. As illustrated in <FIG>, there may be a case where the upper end portion of the vessel BE appears within the measurement range AR without being hidden by the bucket <NUM> depending on the relative positions of the upper end portion of the vessel BE and the lower end portion 12E of the bucket <NUM>.

<FIG> illustrates an example in which the bucket <NUM> is placed within the measurement range AR of the three-dimensional measurement device <NUM>, and an upper end portion 12T of the bucket <NUM> is placed below the upper end portion of the vessel BE. As illustrated in <FIG>, there may be a case where the upper end portion of the vessel BE appears within the measurement range AR without being hidden by the bucket <NUM> depending on relative positions of the upper end portion of the vessel BE and the upper end portion 12T of the bucket <NUM>.

In a case of a state illustrated in <FIG>, the working equipment control unit <NUM> determines that the relative positions of the upper end portion of the vessel BE and the lower end portion of the bucket <NUM> do not satisfy a specified condition. When having determined that the specified condition is not satisfied, the working equipment control unit <NUM> controls motion of the working equipment <NUM> on the basis of, for example, a distance to a closest point that indicates a portion of the transportation vehicle LS, which is closest to the wheel loader <NUM> in a horizontal direction. It should be noted that the working equipment control unit <NUM> may cause the boom <NUM> to rise at predetermined rising speed on the basis of a distance between the three-dimensional measurement device <NUM> and the closest point of the transportation vehicle LS.

In a case of a state illustrated in <FIG>, the working equipment control unit <NUM> determines that the relative positions of the upper end portion of the vessel BE and the lower end portion of the bucket <NUM> satisfy the specified condition. When having determined that the specified condition is satisfied, the working equipment control unit <NUM> controls motion of the working equipment <NUM> on the basis of, for example, the height of the upper end portion of the vessel BE and a distance between the wheel loader <NUM> and the closest point of the transportation vehicle LS.

<FIG> is a flowchart illustrating a method for controlling the wheel loader <NUM> according to the present embodiment, the flowchart including a method for determining a specified condition. <FIG>, and <FIG> are diagrams for describing a method for determining the specified condition.

In the loading work mode in which the wheel loader <NUM> moves forward toward the transportation vehicle LS to load the excavation object excavated by the working equipment <NUM>, the three-dimensional measurement device <NUM> measures a measurement target that includes at least the transportation vehicle LS. The measurement data in the three-dimensional measurement device <NUM> is output to the control device <NUM>. The measurement data acquisition unit <NUM> acquires the measurement data from the three-dimensional measurement device <NUM> (Step S10).

The target calculation unit <NUM> calculates a distance Db between the tip portion 12B of the bucket <NUM> and the transportation vehicle LS on the basis of the measurement data acquired by the measurement data acquisition unit <NUM> and the position data of the bucket (Step S20). The position of the tip portion 12B of the bucket <NUM>, which is the position data of the bucket, can be obtained by using working equipment data of the bucket <NUM> and angle data of the working equipment <NUM>. The angle data of the working equipment <NUM> is detected by the angle sensor <NUM>. The angle of the working equipment <NUM> includes an angle of the boom <NUM> detected by the boom angle sensor <NUM> and an angle of the bucket <NUM> detected by the bucket angle sensor <NUM>. Angle data that indicates the angle of the working equipment <NUM> is output to the bucket calculation unit <NUM>.

The bucket calculation unit <NUM> calculates a position of the lower end portion 12E of the bucket <NUM> on the basis of the angle data of the working equipment <NUM> and the working equipment data of the working equipment <NUM>, the working equipment data being stored in the storage unit <NUM>. The position of the lower end portion 12E of the bucket <NUM> is specified, for example, in the vehicle body coordinate system of the wheel loader <NUM> (Step S30). The position of the lower end portion 12E of the bucket <NUM> is not a predetermined position, but is identified from a position of a lower end portion of the outer shape of the bucket viewed from the three-dimensional measurement device <NUM>.

For example, as illustrated in <FIG>, in a case where the lower end portion 12E of the bucket <NUM> is placed below the upper end portion BEt of the vessel BE, as described with reference to <FIG>, the upper end portion BEt of the vessel BE is hidden by the bucket <NUM>, and the upper end portion BEt of the vessel BE is not placed within the measurement range AR of the three-dimensional measurement device <NUM>. In this state, although an upper end portion BEs of the vessel BE in the measurement data in <FIG> is determined to be the upper end portion of the vessel BE, this determination is incorrect, because a position of the upper end portion BEs of the vessel BE in the measurement data does not match the position of the upper end portion BEt of an actual vessel BE, as illustrated in <FIG>. Therefore, in cases of states illustrated in <FIG> and <FIG>, the working equipment control unit <NUM> determines that the position of the upper end portion BEt of the vessel BE cannot be calculated.

The overlap determination unit <NUM> determines whether or not the upper end portion BEt of the actual vessel BE and the bucket <NUM> overlap each other. In a case where it is determined that the both do not overlap each other, the position of the upper end portion BEs of the vessel BE in the measurement data matches the position of the upper end portion BEt of the actual vessel BE as illustrated in <FIG>, and therefore, it can be determined that height of the upper end portion BEs of the vessel BE in the measurement data is height of the upper end portion BEt of the actual vessel BE.

For example, as illustrated in <FIG>, in a case where a determination angle θ1 formed by a virtual line L1 connecting the three-dimensional measurement device <NUM> and the upper end portion BEs of the vessel BE in the measurement data, and a virtual line L2 connecting the three-dimensional measurement device <NUM> and the lower end portion 12E of the bucket BE is equal to or larger than a predetermined angle, as described with reference to <FIG>, the upper end portion BEt of the vessel BE appears, and the upper end portion BEt of the vessel BE is placed within the measurement range AR of the three-dimensional measurement device <NUM>. In cases of states illustrated in <FIG> and <FIG>, the overlap determination unit <NUM> can determine that the bucket <NUM> and the transportation vehicle LS do not overlap each other. Meanwhile, as illustrated in <FIG>, in a case where the determination angle θ1 is approximately <NUM> degrees, it is highly possible that an actual upper end portion BEt overlaps the bucket <NUM>. In this case, the overlap determination unit <NUM> determines that the actual upper end portion BEt cannot be calculated.

The target calculation unit <NUM> calculates the position of the upper end portion BEs in the measurement data on the basis of the measurement data acquired by the measurement data acquisition unit <NUM>. The position of the upper end portion BEs of the vessel BE is specified, for example, in the vehicle body coordinate system of the wheel loader <NUM> (Step S60).

The working equipment control unit <NUM> calculates the determination angle θ1 on the basis of the calculated position of the lower end portion 12E of the bucket <NUM>, the calculated position of the upper end portion BEs of the vessel BE in the measurement data, and the position of the three-dimensional measurement device <NUM> in the vehicle body coordinate system (Step S70). The position of the three-dimensional measurement device <NUM> in the vehicle body coordinate system is known and stored in the storage unit <NUM>. Furthermore, the position of the lower end portion 12E of the bucket <NUM> and the position of the upper end portion BEs of the vessel BE in the measurement data are specified in the vehicle body coordinate system. Therefore, the working equipment control unit <NUM> can calculate the determination angle θ1.

The working equipment control unit <NUM> determines whether or not a determination angle θ is equal to or larger than a predetermined threshold (Step S80). The threshold is an angle larger than <NUM> [°]. In the present embodiment, the threshold is <NUM> [°], for example. This is because it is not possible to determine whether or not the upper end portion BEs of the vessel BE in the measurement data is the upper end portion BEt of the actual vessel BE, unless the virtual line L1 and the virtual line L2 are separated from each other to some extent.

In Step S80, in a case where it is determined that the determination angle θ1 is not equal to or larger than the threshold (Step S80: No), the working equipment control unit <NUM> controls motion of the working equipment <NUM> on the basis of the distance Db from the wheel loader <NUM> to the transportation vehicle LS (Step S50).

In Step S80, in a case where it is determined that the determination angle θ is equal to or larger than the threshold (Step S80: Yes), the target calculation unit <NUM> calculates height Hb of the upper end portion BEt of the vessel BE from the ground RS on the basis of the position of the upper end portion of the vessel BE (Step S85).

The working equipment control unit <NUM> controls motion of the working equipment <NUM> on the basis of the height Hb of the upper end portion of the vessel BE and the distance Db from the wheel loader <NUM> to the transportation vehicle LS (Step S90).

That is, as described with reference to <FIG>, in a state where the wheel loader <NUM> is moving forward to approach the transportation vehicle LS, and on the basis of the height of the upper end portion of the vessel BE and the distance to the transportation vehicle LS, which are calculated by the target calculation unit <NUM>, the working equipment control unit <NUM> causes the boom <NUM> to perform rising motion by controlling an angle of the bucket <NUM> so that the bucket <NUM> is placed above the upper end portion of the vessel BE and that the excavation object held by the bucket <NUM> does not spill out of the bucket <NUM>. After the boom <NUM> performs rising motion and the bucket <NUM> is placed above the vessel BE, the working equipment control unit <NUM> controls the working equipment <NUM> so that the bucket <NUM> performs tilting motion. With this arrangement, the excavation object is discharged from the bucket <NUM> and loaded to the vessel BE.

Furthermore, the travel speed of the wheel loader <NUM> and height of the bucket at a moment may be taken into consideration. With this arrangement, it is possible to control the working equipment <NUM> at optimal rising speed so that the position of the tip portion 12B is higher than the upper end portion BEt of the vessel BE immediately before the tip portion 12B reaches the closest point of the transportation vehicle LS.

In the present embodiment, even if the upper end portion of the vessel BE appears within the measurement range AR, the working equipment control unit <NUM> controls the working equipment <NUM> without reference to the height of the upper end portion of the vessel BE but only on the basis of the distance to the vessel BE, until the determination angle θ1 is determined to be equal to or larger than the threshold.

It should be noted that, in the present embodiment, it is determined whether or not a specified condition is satisfied on the basis of the determination angle θ1. In a case where the bucket <NUM> is located below as illustrated in <FIG>, it may be determined that the upper end portion BEt of the actual bucket BE can be calculated if a determination angle θ2 formed by a virtual line L1 connecting the three-dimensional measurement device <NUM> and the upper end portion BEt of the vessel BE, and a virtual line L2 connecting the three-dimensional measurement device <NUM> and the upper end portion 12T of the bucket <NUM> is equal to or larger than a predetermined angle (a direction opposite to θ1). Furthermore, in a case where the bucket <NUM> is located below, if even a small portion of the vessel BE is detected, the position of the upper end portion BEs of the vessel BE in the measurement data matches the position of the upper end portion BEt of the actual vessel BE as illustrated in <FIG>, and therefore, it can be determined that the upper end portion BEt of the actual bucket BE can be calculated.

The overlap determination unit <NUM> may determine there is overlap not only in a case where an entire region of the upper end portion BEs of the vessel BE in the measurement data overlaps the bucket, but also in a case where, for example, a predetermined proportion of a region of the upper end portion BEs of the vessel BE in the measurement data overlaps the bucket.

It should be noted that whether or not the specified condition is satisfied may be determined on the basis of height He of the lower end portion 12E of the bucket <NUM> from the ground RS, the height He being based on the ground RS. For example, height of the upper end portion BEs of the vessel BE in the measurement data may be obtained in a case where the height He of the lower end portion 12E of the bucket <NUM> is higher by a predetermined distance than the upper end portion BEs of the vessel BE in the measurement data. The ground RS may be specified on the basis of a ground contact surface of the tires <NUM>, for example. A position of the ground contact surface of the tires <NUM> is known data specified in the vehicle body coordinate system, for example.

It should be noted that, in a case where the wheel loader <NUM> is provided with an inertial measurement unit (Inertial Measurement Unit: IMU) or a tilt sensor, a position of the ground RS may be identified on the basis of detection data of the inertial measurement device or tilt sensor.

Next, a method for calculating the position of the upper end portion BEs of the vessel BE in measurement data of the stereo camera <NUM> will be described.

In the loading work mode in which the wheel loader <NUM> moves forward toward the transportation vehicle LS to load the excavation object excavated by the working equipment <NUM>, the stereo camera <NUM> measures the transportation vehicle LS. The measurement data acquisition unit <NUM> acquires, from the stereo camera <NUM>, the measurement data of the transportation vehicle LS measured by the stereo camera <NUM>.

The stereo camera <NUM> measures distances to each of a plurality of measurement points PI on a surface of the transportation vehicle LS.

<FIG> is a diagram illustrating an example of image data including the transportation vehicle LS acquired by the stereo camera <NUM> according to the present embodiment. In <FIG>, an image illustrating the bucket <NUM> is omitted. It should be noted that, although only one measurement point PI (point data) is illustrated in <FIG>, a measurement point PI is set for each pixel of the image data illustrated in <FIG>. The stereo camera <NUM> can obtain point cloud data, namely three-dimensional data, which corresponds to each pixel by performing stereo processing on the image data.

On the basis of image data that is the measurement data of the stereo camera <NUM>, the target calculation unit <NUM> calculates distances from the stereo camera <NUM> in the vehicle body coordinate system to the plurality of measurement points PI on the surface of the transportation vehicle LS that are viewed in each pixel. The target calculation unit <NUM> calculates a three-dimensional shape of the transportation vehicle LS on the basis of the distances to each of the plurality of measurement points PI on the surface of the transportation vehicle LS.

Next, the target calculation unit <NUM> creates a histogram illustrating a relation between distances from the stereo camera <NUM> and the number of data of measurement points PI that indicates the distances.

<FIG> is a schematic diagram illustrating a histogram that indicates a relation between distances from the stereo camera <NUM> to the measurement points PI, and the number of data of the measurement points PI existing for each distance. Each distance has a constant distance width.

Because the image data illustrated in <FIG> includes a measurement target other than the transportation vehicle LS, such as ground for example, histogram data exists over a wide range of distances, as illustrated in <FIG>. Meanwhile, a side surface region of the transportation vehicle LS occupies a large proportion of the image data illustrated in <FIG>. Furthermore, a side surface of the transportation vehicle LS stands substantially vertically from ground, and distances from the stereo camera <NUM> to each of measurement points on the side surface of the transportation vehicle LS are substantially constant. Therefore, in the histogram, a large amount of data is counted for the distances from the stereo camera <NUM> to the measurement points PI of the transportation vehicle LS. The target calculation unit <NUM> determines that three-dimensional data within a distance width for which the large amount of data is counted to be measurement data of the transportation vehicle LS. Then, the target calculation unit <NUM> calculates the distance Db from the wheel loader <NUM> to the transportation vehicle LS on the basis of the three-dimensional data determined to be the measurement data of the transportation vehicle LS and the position data of the bucket <NUM>. Furthermore, the target calculation unit <NUM> calculates height of the upper end portion BEs of the vessel BE in the measurement data on the basis of the three-dimensional data determined to be the measurement data of the transportation vehicle LS.

The working equipment control unit <NUM> controls the working equipment <NUM> on the basis of the height Hb of the upper end portion of the vessel BE and the distance Db to the transportation vehicle LS that are calculated by the target calculation unit <NUM>.

Next, a method for calculating a position of an upper end portion of the vessel BE based on measurement data of the laser radar <NUM> will be described.

<FIG> schematically illustrates a measuring method by the laser radar <NUM>. It should be noted that, in <FIG>, a diagram illustrating the bucket <NUM> is omitted. As illustrated in <FIG>, the laser radar <NUM> measures distances to each of a plurality of irradiation points PJ on the surface of the transportation vehicle LS. The measurement data acquisition unit <NUM> acquires three-dimensional data including position data of each of the irradiation points PJ. The target calculation unit <NUM> divides the measured three-dimensional data into a ground group and a transportation vehicle group.

The target calculation unit <NUM> calculates the distance Db from the wheel loader <NUM> to the transportation vehicle LS, from three-dimensional data in the transportation vehicle group and position data of the working equipment <NUM>.

The target calculation unit <NUM> extracts an irradiation point PJ existing at a highest position among the three-dimensional data in the transportation vehicle group, and calculates the height Hb of the upper end portion BEt of the vessel BE on the basis of this irradiation point PJ.

As described above, according to the present embodiment, when relative positions of the upper end portion of the vessel BE and the lower end portion of the bucket <NUM> satisfy a specified condition, the working equipment control unit <NUM> controls the working equipment <NUM> on the basis of a position of the upper end portion of the vessel BE and a distance from the wheel loader <NUM> to the transportation vehicle LS. In a state where the upper end portion of the vessel BE is hidden by the bucket <NUM>, it is highly possible that a position of the upper end portion BEs of the vessel BE in the measurement data calculated by the target calculation unit <NUM> does not match a position of the upper end portion BEt of the actual vessel BE. In the present embodiment, when the upper end portion of the vessel BE is not blocked by the bucket <NUM> and satisfies a specified condition of being placed within the measurement range AR of the three-dimensional measurement device <NUM>, the working equipment control unit <NUM> controls the working equipment <NUM> on the basis of the position of the upper end portion of the vessel BE calculated by the target calculation unit <NUM>. With this arrangement, the working equipment control unit <NUM> can control the working equipment <NUM> on the basis of the position of the upper end portion of the vessel BE that is accurately calculated. Furthermore, when the specified condition is not satisfied, the working equipment control unit <NUM> controls the working equipment <NUM> without reference to the position of the upper end portion of the vessel BE. With this arrangement, the working equipment control unit <NUM> can prevent controlling the working equipment <NUM> on the basis of incorrect measurement data.

<FIG> is a block diagram illustrating an example of a computer system <NUM>. The above-described control device <NUM> includes the computer system <NUM>. The computer system <NUM> has a processor <NUM> such as a central processing unit (CPU), a main memory <NUM> including a non-volatile memory such as a read only memory (RAM) and a volatile memory such as a random access memory (RAM), a storage <NUM>, and an interface <NUM> including an input/output circuit. A function of the above-described control device <NUM> is stored in the storage <NUM> as a program. The processor <NUM> reads the program from the storage <NUM>, expands the program to the main memory <NUM>, and executes the above-described processing according to the program. It should be noted that the program may be delivered to the computer system <NUM> via a network.

It should be noted that, in the above-described embodiment, the wheel loader <NUM> is provided with both the laser radar <NUM> and the stereo camera <NUM> as the three-dimensional measurement device <NUM>. One of the laser radar <NUM> or the stereo camera <NUM> may be provided in the wheel loader <NUM>. Furthermore, the three-dimensional measurement device <NUM> is required at least to measure a three-dimensional shape of a work target and relative positions with the work target, and is not limited to the laser radar <NUM> and the stereo camera <NUM>.

In the above-described embodiment, instead of the three-dimensional measurement device <NUM>, an image of the measurement target may be acquired by using an imaging device as a measurement device, and whether or not a bucket <NUM> overlaps an upper end portion of a vessel BE may be determined with image recognition by artificial intelligence (Artificial Intelligence: AI), or the like. Furthermore, presence of overlap of the bucket <NUM> and the upper end portion of the vessel BE may be determined by an analysis by AI, or the like, on the basis of three-dimensional data measured by the three-dimensional measurement device <NUM>.

In the above-described embodiment, whether or not an upper end portion BEs of the vessel BE in measurement data is hidden by the bucket <NUM> is determined. However, not limited to the form, for example, whether or not an entire transportation vehicle LS in the measurement data is hidden by the bucket <NUM> may be determined. Then, for example, the working equipment control unit <NUM> may not control the working equipment <NUM> in a case where a region larger than a predetermined proportion with respect to a region of the entire transportation vehicle LS in the measurement data overlaps the bucket <NUM>, and the working equipment control unit <NUM> may control the working equipment <NUM> on the basis of a position of a measured loading target when it is determined that only a region of equal to or less than the predetermined proportion with respect to the region of the entire transportation vehicle LS overlaps the bucket.

In the above-described embodiment, the working equipment <NUM> is controlled on the basis of distance Db to the transportation vehicle LS in a case where it is determined that the upper end portion BEs of the vessel BE in the measurement data is hidden by the bucket <NUM>. However, not limited to the form, the working equipment <NUM> may not be controlled, or the working equipment <NUM> may be controlled to rise at predetermined rising speed, in a case where, for example, it is determined that the upper end portion BEs of the vessel BE in the measurement data is hidden by the bucket <NUM>.

Alternatively, a target calculation unit <NUM> may store in a storage unit <NUM> height Hb of an upper end portion BEt of the vessel BE measured in a state as illustrated in <FIG>, and may control the working equipment <NUM> on the basis of the stored height Hb of the upper end portion BEt of the vessel BE even in a case where it is determined that the upper end portion BEt of the vessel BE is hidden by the bucket <NUM> in a state as illustrated in <FIG>.

It should be noted that, in each of the above-described embodiments, the work site where the wheel loader <NUM> performs work may be a mining site of a mine, or may be a construction site or a building site.

It should be noted that the wheel loader <NUM> may be used for snow removal work, may be used for work in agriculture or livestock farming, or may be used for work in forestry.

It should be noted that, in the above-described embodiments, the bucket <NUM> may have a plurality of blades or may have a straight cutting edge.

It should be noted that a work member coupled to a tip portion of a boom <NUM> may not necessarily be the bucket <NUM> but may be a snow plow or snow bucket used for snow removal work, a bale glove or fork used for work in agriculture or livestock farming, or a fork or bucket used for work in forestry.

Claim 1:
A loading machine control device (<NUM>) comprising:
a measurement data acquisition unit (<NUM>) that acquires measurement data of a measurement device (<NUM>) mounted in a loading machine (<NUM>) that has working equipment (<NUM>);
a target calculation unit (<NUM>) that calculates, on the basis of the measurement data, a position of an upper end portion (BEs) of a loading target (BE) to which an excavation object excavated by a bucket (<NUM>) of the working equipment (<NUM>) is loaded;
a bucket calculation unit (<NUM>) that calculates position data of the bucket (<NUM>);
an overlap determination unit (<NUM>) that determines whether or not the upper end portion (BEs) of the loading target (BE) and the bucket (<NUM>) that are in the measurement data overlap each other;
a working equipment control unit (<NUM>) that controls the working equipment (<NUM>) on the basis of the measured position of the upper end portion (BEs) of the loading target (BE) when it is determined that the upper end portion (BEs) of the loading target (BE) and the bucket (<NUM>) that are in the measurement data do not overlap each other;
wherein the overlap determination unit (<NUM>) determines whether or not there is overlap on the basis of relative positions of the measurement device (<NUM>), the upper end portion (BEs) of the loading target (BE), and the bucket (<NUM>),
characterized in that the bucket calculation unit (<NUM>) calculates a position of a lower end portion (12E) of the bucket (<NUM>), and
the target calculation unit (<NUM>) calculates the position of the upper end portion (BEs) of the loading target (BE) when an angle specified on the basis of the measurement device (<NUM>), the upper end portion (BEs) of the loading target (BE), and the lower end portion (12E) of the bucket (<NUM>) is equal to or larger than a predetermined angle.