JP7704430B2 - Swing control device and method - Google Patents

Description

The present invention relates to a turning control device and a turning control method for automatically turning a tracked vehicle equipped with crawlers (crawler tracks, tracks, track belts, caterpillars) for running on the left and right.

Tracked vehicles have crawlers on the left and right for travel. Tracked vehicles can achieve high maneuverability on rough ground. For example, Patent Document 1 shows a tracked vehicle that uses an electric motor as a power source.

Japanese Patent Application Publication No. 11-46403

When a tracked vehicle makes a pivot turn or a yaw turn, the crawlers push soil in the direction of the turn. For example, when a tracked vehicle makes a pivot turn to the left, soil clods are formed on the left side of the front half of each crawler and on the right side of the rear half of each crawler. As the turning angle of the tracked vehicle increases, the soil clods become larger and the ground becomes rough. Furthermore, when a tracked vehicle makes a pivot turn while pushing a large soil clod, the power source (such as an electric motor) needs to generate a large torque. This increases the amount of energy consumed by the tracked vehicle. For these reasons, there is a need for a turning method that damages fields as little as possible when the tracked vehicle turns and allows it to turn with little power.

The present invention aims to solve the above-mentioned problems.

The first aspect of the present invention is a turning control device that automatically turns a tracked vehicle equipped with crawlers for travel on the left and right, and includes a turning control unit that controls the left and right crawlers to make the tracked vehicle make a pivot turn or a yaw turn until the turning angle of the tracked vehicle reaches a target turning angle, and a movement control unit that temporarily suspends the pivot turn or yaw turn by the turning control unit each time the tracked vehicle turns a predetermined division angle, and controls the left and right crawlers to move the tracked vehicle forward or backward a predetermined distance.

The second aspect of the present invention is a turning control method that uses a computer to automatically control the turning of a tracked vehicle equipped with crawlers for travel on the left and right, and includes a turning process that controls the left and right crawlers to make the tracked vehicle make a pivot turn or a yaw turn until the turning angle of the tracked vehicle reaches a target turning angle, and a moving process that temporarily suspends the pivot turn or yaw turn in the turning process each time the tracked vehicle turns a predetermined division angle, and controls the left and right crawlers to move the tracked vehicle forward or backward a predetermined distance.

The present invention can reduce damage to the ground and energy consumption.

FIG. 1 is a block diagram showing a tracked vehicle according to a first embodiment. FIG. 2 is a flowchart showing a flow of control performed by a computing device provided in the driving control device. FIG. 3 is an explanatory diagram showing a first example of turning operation of a tracked vehicle in a time series manner. FIG. 4 is an explanatory diagram showing a second example of the turning operation of the tracked vehicle in a time series manner.

[1 Configuration of tracked vehicle 10]
FIG. 1 is a block diagram showing a tracked vehicle 10. The tracked vehicle 10 is equipped with crawlers 12R, 12L on the left and right sides of the vehicle body. The tracked vehicle 10 can move forward, backward, and turn by driving the left and right crawlers 12R, 12L. The tracked vehicle 10 of this embodiment is a vehicle that automatically performs turning control. For example, the tracked vehicle 10 is an autonomous vehicle that automatically performs running control and turning control.

The tracked vehicle 10 of this embodiment has electric motors (travel motors 50R, 50L) as a power source, but may also have an engine, hydraulic motor, etc. as a power source. The tracked vehicle 10 of this embodiment has a pair of electric motors that correspond individually to the left and right crawlers 12R, 12L, but may also have a single electric motor. The output of the single electric motor is distributed and supplied to the left and right crawlers 12R, 12L. Note that in this embodiment, the tracked vehicle 10 is assumed to be a small transport machine that moves forward by following a preceding object to be followed (e.g. a person). The small transport machine transports, for example, agricultural crops harvested by a person in a field.

The tracked vehicle 10 has an input device group 16, a driving control device 18, a battery 20, two motor control circuits 22R, 22L, and left and right drive devices 24R, 24L. The input device group 16 includes one or more cameras 26 and an inertial measurement device 28. The one or more cameras 26 are sensors that acquire information such as the position of the target to be tracked. LiDAR may be used as a sensor that acquires information about the target to be tracked. In addition, other tracking systems using beacons or the like may be used to make the tracked vehicle 10 automatically track the target to be tracked. In addition, an attitude and orientation reference device may be used instead of the inertial measurement device 28. The drive device 24R includes a traveling motor 50R, a power transmission mechanism 52R, and a crawler 12R. The drive device 24L includes a traveling motor 50L, a power transmission mechanism 52L, and a crawler 12L. The traveling motors 50R, 50L are the power sources of the tracked vehicle 10.

In the following, the motor control circuits 22R, 22L are also simply referred to as the motor control circuits 22. The travel motors 50R, 50L are also simply referred to as the travel motors 50. The power transmission mechanisms 52R, 52L are also simply referred to as the power transmission mechanisms 52. The crawlers 12R, 12L are also simply referred to as the crawlers 12.

The cameras 26 capture images of the area around the tracked vehicle 10. At least one of the cameras 26 captures images of the area in front of the tracked vehicle 10. The cameras 26 output image data acquired by capturing images to the cruise control device 18. The inertial measurement unit 28 has a three-axis gyro and three-directional acceleration sensors. The inertial measurement unit 28 measures the acceleration and turning angular velocity of the tracked vehicle 10. The inertial measurement unit 28 outputs the measurement data to the cruise control device 18.

The driving control device 18 controls the driving (forward, backward, turning, etc.) of the tracked vehicle 10. In other words, the driving control device 18 functions as a turning control device. The driving control device 18 has a calculation device 32 and a storage device 34.

The arithmetic device 32 is a computer and has a processing circuit. The processing circuit may be a processor such as a CPU. The processing circuit may be an integrated circuit such as an ASIC or an FPGA. The processor can execute various processes by executing programs stored in the storage device 34. The arithmetic device 32 functions as an acquisition unit 36, a target recognition unit 38, a position recognition unit 40, an operation determination unit 42, a travel control unit 44, a turning control unit 46, and a movement control unit 48. At least some of the multiple processes may be executed by electronic circuits including discrete devices.

The acquisition unit 36 acquires various data (image data from the camera 26, measurement data from the inertial measurement device 28, etc.) from the input device group 16. The target recognition unit 38 performs image recognition using the image data to recognize the target (person) to be followed. The position recognition unit 40 recognizes the position of the tracked vehicle 10 in the field and the orientation of the tracked vehicle 10 based on the measurement data. The operation determination unit 42 determines the operation of the tracked vehicle 10, such as the running direction (movement direction), running speed, whether or not turning is required, the angle to turn, etc., based on the recognition results of the target recognition unit 38 and the recognition results of the position recognition unit 40. The traveling control unit 44 performs running control of the tracked vehicle 10 based on the determination results of the operation determination unit 42. The turning control unit 46 performs turning control of the tracked vehicle 10 based on the determination results of the operation determination unit 42. The movement control unit 48 performs movement control of the tracked vehicle 10 based on the determination results of the operation determination unit 42.

The storage device 34 has a volatile memory and a non-volatile memory. Examples of the volatile memory include RAM. The volatile memory is used as a working memory for the processor. The volatile memory temporarily stores data and the like required for processing or calculation. Examples of the non-volatile memory include ROM and flash memory. The non-volatile memory is used as a storage memory. The non-volatile memory stores programs, tables, maps, and the like. At least a portion of the storage device 34 may be provided in the processor, integrated circuit, and the like as described above.

The storage device 34 stores various predetermined values used in various controls. For example, the storage device 34 stores, as the predetermined values, a division angle as a predetermined angle for turning the tracked vehicle 10 at one turning center position, and a predetermined distance that the tracked vehicle 10 moves forward and backward during turning. As the division angle, for example, a calculated value of (length of turning arc corresponding to width D of crawler 12)/(turning radius of pivot turning) is set in advance. This division angle is a turning angle that moves the front and rear ends of the crawler 12 in the turning direction by about the width D of the crawler 12. More specifically, this division angle is the angle at which the right front end of the crawler 12L turns in the turning direction when the tracked vehicle 10 turns left until it reaches the position of the left side of the crawler 12L before turning. Additionally, this division angle is the angle through which the left front end of the crawler 12R turns when the tracked vehicle 10 turns right before it reaches the position of the right side of the crawler 12R before turning.

The motor control circuit 22 has an inverter circuit and the like. The switching elements of the inverter circuit are switched in response to a control signal output by the calculation device 32. The motor control circuit 22 converts the direct current of the battery 20 into alternating current and outputs it to the driving motor 50.

The traveling motor 50 is an electric motor, for example a three-phase AC motor. The traveling motor 50 is driven by power supplied from the battery 20 via the motor control circuit 22. The output shaft of the traveling motor 50 is connected to a drive wheel (not shown) via a power transmission mechanism 52. The power transmission mechanism 52 has, for example, a reducer. The drive wheel rotates the crawler 12.

[2. Turning control and movement control]
FIG. 2 is a flowchart showing the flow of control performed by the arithmetic unit 32 provided in the travel control device 18. When the tracked vehicle 10 travels following a target, the operation determination unit 42 determines the rotation direction and rotation speed of each travel motor 50 so that the orientation of the tracked vehicle 10 coincides with the direction of the target. The operation determination unit 42 determines that turning is necessary when the angle difference between the orientation of the tracked vehicle 10 and the direction of the target is equal to or greater than a predetermined value. In this specification, this angle difference is referred to as the angle at which the vehicle should turn, that is, the target angle of turning. The operation determination unit 42 calculates the target angle and stores it in the storage device 34. The storage device 34 stores the target angle until the turning is completed. When the tracked vehicle 10 turns, the travel control device 18 performs the process shown in FIG. 2.

In step S1, the turning control unit 46 performs turning control. Here, the turning control unit 46 performs control of a whirlpool turn as the turning control. Note that the turning control unit 46 may also perform control of a whirlpool turn as the turning control. The turning control unit 46 performs a whirlpool turn by rotating the driving motor 50R and the driving motor 50L in opposite directions. During a whirlpool turn, the turning control unit 46 may make the rotation speed of the driving motor 50R and the rotation speed of the driving motor 50L equal to each other, or may make them different from each other. When step S1 ends, the process proceeds to step S2.

In step S2, the acquisition unit 36 acquires measurement data from the inertial measurement device 28. The position recognition unit 40 calculates a first turning angle and a second turning angle based on the measurement data. The first turning angle is the angle at which the tracked vehicle 10 turns continuously at the same position. The maximum allowable value of the first turning angle is the divided angle. On the other hand, the second turning angle is the angle at which the tracked vehicle 10 turns from when it starts turning to the time when the latest turning angle is calculated. The maximum allowable value of the second turning angle is the target angle. When step S2 ends, the process proceeds to step S3.

In step S3, the turning control unit 46 compares the second turning angle with the target angle. If the second turning angle is less than the target angle (step S3: YES), the process proceeds to step S4. At this stage, turning has not ended. Therefore, the turning control unit 46 continues turning control. On the other hand, if the second turning angle is equal to or greater than the target angle (step S3: NO), the series of processes shown in FIG. 2 ends. At this stage, the tracked vehicle 10 is heading toward the target to be followed.

When moving from step S3 to step S4, the turning control unit 46 compares the first turning angle with the division angle. If the first turning angle is equal to or greater than the division angle (step S4: YES), the process moves to step S5. At this stage, turning up to the division angle is complete. On the other hand, if the first turning angle is less than the division angle (step S4: NO), the process returns to step S1. At this stage, turning up to the division angle and turning up to the target angle are not complete. Therefore, the turning control unit 46 continues turning control.

When the process moves from step S4 to step S5, the movement control unit 48 temporarily suspends the turning control performed by the turning control unit 46. When step S5 ends, the process moves to step S6.

In step S6, the movement control unit 48 rotates each of the travel motors 50 a predetermined amount in the same direction, thereby moving the tracked vehicle 10 forward or backward a predetermined distance. After rotating each of the travel motors 50 a predetermined amount in the same direction, the movement control unit 48 releases the suspension of turning control. When step S6 ends, the process proceeds to step S7.

In step S7, the position recognition unit 40 resets the first rotation angle. When step S7 ends, the process returns to step S1.

[3 Operation of the Tracked Vehicle 10]
[3-1 First Example]
3 is an explanatory diagram showing a first example of a turning operation of the tracked vehicle 10 in a time series. The first example is a control example in which the movement control unit 48 moves the tracked vehicle 10 forward in the movement control (step S6 in FIG. 2).

Between time t0 and time t1, the turning control unit 46 makes the tracked vehicle 10 make a pivot turn counterclockwise (arrow A) (step S1 in Figure 2). While the tracked vehicle 10 is turning, clods of soil 56 are formed to the left of the front half of the crawler 12 and to the right of the rear half of the crawler 12. In Figure 3, the dotted area is the clods of soil 56.

At time t1, the turning control unit 46 determines that the first turning angle has reached the division angle (step S4 in FIG. 2: YES). The turning control unit 46 temporarily suspends turning control (step S5 in FIG. 2).

Between time t1 and time t2, the movement control unit 48 moves the tracked vehicle 10 forward (arrow B) a predetermined distance. (Step S6 in FIG. 2). By moving the tracked vehicle 10 forward by more than half L/2 of the crawler length L, the front half of the crawler 12 can move to a position where there is no soil mass 56 on the left side, and the rear half of the crawler 12 can move to a position where there is no soil mass 56 on the right side. On the other hand, if the moving distance of the tracked vehicle 10 is too long, the positional deviation of the turning center of the tracked vehicle 10 becomes large until the turning angle of the tracked vehicle 10 reaches the target angle. In order to reduce the positional deviation of the turning center, it is preferable that the predetermined distance is as small as possible. From the above, it is preferable that the predetermined distance that the tracked vehicle 10 moves during one turning interruption is more than half L/2 of the crawler length L and is less than the crawler length L. More specifically, it is preferable that the predetermined distance is half L/2 of the crawler length L. The crawler length L is the length from the front end of the crawler 12 to the rear end of the crawler 12.

After time t2 (time t2, time t3, etc.), the turning control unit 46 performs the same control as that performed from time t0 to time t2 until the second turning angle reaches the target angle. When the second turning angle reaches the target angle, the turning control unit 46 ends the turning control. At this point, the tracked vehicle 10 is facing the target to be followed. The traveling control unit 44 controls each traveling motor 50 so that the tracked vehicle 10 travels following the target to be followed.

In this way, in the first example, the travel control device 18 (turning control device) alternates between turning control and movement control when turning the tracked vehicle 10 by the target angle. In other words, the tracked vehicle 10 turns by the target angle while moving the turning position (turning center position). The size of each earth lump 56 formed by the first example is smaller than the size of the earth lump 56 formed by turning by the target angle at one location. Therefore, the travel control device 18 can reduce the size of the earth lump 56 formed when the tracked vehicle 10 turns. As a result, the torque required for the travel motor 50 when the tracked vehicle 10 turns is reduced. In other words, the travel control device 18 can reduce roughness of the ground and reduce power consumption by performing the operation of the first example.

[3-2 Second Example]
4 is an explanatory diagram showing a second example of the turning operation of the tracked vehicle 10 in a time series. The second example is a control example in which the movement control unit 48 alternates between moving the tracked vehicle 10 forward and moving the tracked vehicle 10 backward.

The operation from time t0 to time t3 in the second example is the same as the operation from time t0 to time t3 in the first example. The first and second examples differ in the movement direction of the tracked vehicle 10 from time t3 to time t4, i.e., the movement direction of the second movement control. In the first example, after time t3, the movement control unit 48 moves the tracked vehicle 10 forward (arrow B) a predetermined distance (distance L/2, half the crawler length L). On the other hand, in the second example, from time t3 to time t4, the movement control unit 48 moves the tracked vehicle 10 backward (arrow C) a predetermined distance (distance L/2, half the crawler length L).

In this way, in the second example, the movement control unit 48 moves the tracked vehicle 10 forward during odd-numbered movement controls (step S6 in FIG. 2) and moves the tracked vehicle 10 backward during even-numbered movement controls (step S6 in FIG. 2). The movement control unit 48 may also move the tracked vehicle 10 backward during odd-numbered movement controls and move the tracked vehicle 10 forward during even-numbered movement controls. In short, the movement control unit 48 makes the movement direction of the tracked vehicle 10 at the nth (n is a natural number equal to or greater than 2) turning interruption the opposite direction to the movement direction of the tracked vehicle 10 at the n-1th turning interruption.

The movement control unit 48 may also move forward and backward in a pre-set sequence.

By performing the operation of the second example, the travel control device 18 can not only achieve the same effect as the first example, but also further reduce the positional deviation of the turning center. In addition, the travel control device 18 alternates the moving direction of the tracked vehicle 10, so that the tracked vehicle 10 moves over a part of the soil mass 56 formed immediately before the nth movement. Then, the soil mass 56 is compacted. In other words, by performing the operation of the second example, the travel control device 18 can reduce roughness of the ground even more than the first example. Furthermore, the travel control device 18 can turn the tracked vehicle 10 by an angle equivalent to the width D of the crawler 12 and move it forward and backward in the opposite direction to the forward and backward movement direction after the previous turn. This allows the tracked vehicle 10 to move without overlapping with an area already compacted by the crawler 12. In this way, the travel control device 18 can efficiently reduce roughness of the ground.

[4 Other embodiments]
The tracked vehicle 10 of the above-mentioned embodiment moves forward while following the target (person). However, the tracked vehicle 10 may move forward along a preset travel route. In this case, the target recognition unit 38 recognizes the travel route. The operation determination unit 42 determines the direction in which the tracked vehicle 10 should travel, the angle at which the tracked vehicle 10 should turn, etc., based on the travel route recognized by the target recognition unit 38 and the position and orientation of the tracked vehicle 10 recognized by the position recognition unit 40.

Alternatively, the tracked vehicle 10 may be a manned vehicle in which the user controls everything other than turning, and only turning is performed automatically. The tracked vehicle 10 may also be a remote-operated vehicle operated by a user from a remote location. When the tracked vehicle 10 is a manned or remote-operated vehicle, for example, the user issues a turning instruction (such as a button operation), and the turning control unit 46 and the movement control unit 48 perform the automatic control shown in FIG. 2.

The position recognition unit 40 does not need to use the measurement data of the inertial measurement unit 28 when calculating the turning angle of the tracked vehicle 10. For example, the position recognition unit 40 can calculate the turning angle of the tracked vehicle 10 based on the turning time, the load of the power source (the current value of the driving motor 50 in the above embodiment), etc.

The division angle may be variable. For example, the operation determination unit 42 may calculate the division angle by dividing the target angle into predetermined equal parts.

The division angle may be set according to the soil conditions at the location where the tracked vehicle 10 is working. For example, a small division angle may be set for soft soil. Also, a large division angle may be set for hard soil.

[5. Invention Obtained from the Embodiments]
The invention that can be understood from the above embodiment will be described below.

The first aspect of the present invention is a turning control device (18) that automatically turns a tracked vehicle (10) equipped with left and right crawlers (12) for travel, and includes a turning control unit (46) that controls the left and right crawlers to make the tracked vehicle make a pivot turn or a yaw turn until the turning angle of the tracked vehicle reaches a target turning angle, and a movement control unit (48) that temporarily suspends the pivot turn or yaw turn by the turning control unit each time the tracked vehicle turns a predetermined division angle, and controls the left and right crawlers to move the tracked vehicle forward or backward a predetermined distance.

In a first aspect, the movement control unit may move the tracked vehicle forward or backward a distance equal to or greater than half the crawler length (L), which is the length from the front end of the crawler to the rear end of the crawler, and equal to or less than the crawler length.

In a first aspect, the movement control unit may move the tracked vehicle forward or backward a distance equal to half the crawler length.

In a first aspect, the movement control unit may set the movement direction of the tracked vehicle at the nth (n is a natural number equal to or greater than 2) turning interruption to be opposite to the movement direction of the tracked vehicle at the n-1th turning interruption.

In a first embodiment, the power source of the tracked vehicle may be an electric motor (50).

In a first aspect, when the tracked vehicle is made to make a pivot turn, the turning control unit may set the division angle to (length of the turning arc equivalent to the width (D) of the crawler)/(turning radius of the pivot turn).

In the first aspect, the division angle may be set according to the soil conditions at the location where the tracked vehicle is performing work.

The second aspect of the present invention is a turning control method that uses a computer to automatically control the turning of a tracked vehicle equipped with crawlers for travel on the left and right, and includes a turning process that controls the left and right crawlers to make the tracked vehicle make a pivot turn or a yaw turn until the turning angle of the tracked vehicle reaches a target turning angle, and a moving process that temporarily suspends the pivot turn or yaw turn in the turning process each time the tracked vehicle turns a predetermined division angle, and controls the left and right crawlers to move the tracked vehicle forward or backward a predetermined distance.

10: Tracked vehicle 12: Crawler 18: Travel control device (turning control device) 46: Turning control unit 48: Movement control unit 50: Travel motor (electric motor)

Claims (8)

A turning control device for automatically turning a tracked vehicle having crawlers for traveling on the left and right sides,
a turning control unit that controls the left and right crawlers to make the tracked vehicle perform a pivot turn or a yaw turn until the turning angle of the tracked vehicle reaches a target turning angle;
A turning control device comprising: a movement control unit that temporarily suspends the pivot turning or swivel turning performed by the turning control unit each time the tracked vehicle turns by a predetermined divided angle, and controls the left and right crawlers to move the tracked vehicle forward or backward by a predetermined distance. The turning control device according to claim 1,
The movement control unit is a turning control device that moves the tracked vehicle forward or backward a distance equal to or greater than half the crawler length, which is the length from the front end of the crawler to the rear end of the crawler, and less than or equal to the crawler length. The turning control device according to claim 2,
The movement control unit is a turning control device that moves the tracked vehicle forward or backward a distance equal to half the crawler length. The turning control device according to any one of claims 1 to 3,
The movement control unit is a turning control device that changes the movement direction of the tracked vehicle at the nth (n is a natural number greater than or equal to 2) turning interruption to the opposite direction to the movement direction of the tracked vehicle at the n-1th turning interruption. The turning control device according to any one of claims 1 to 4,
A turning control device in which the power source of the tracked vehicle is an electric motor. The turning control device according to any one of claims 1 to 5,
The turning control unit is a turning control device that sets the divided angle to (length of turning arc corresponding to width of the crawler) / (turning radius of the pivot turn) when the tracked vehicle is made to make a pivot turn. The turning control device according to any one of claims 1 to 5,
A turning control device in which the division angle is set according to the soil conditions at the location where the tracked vehicle is working. A method for automatically controlling the turning of a tracked vehicle having crawlers for traveling on the left and right sides, comprising the steps of:
a turning process for controlling the left and right crawlers to perform a pivot turn or a yaw turn of the tracked vehicle until the turning angle of the tracked vehicle reaches a target turning angle;
A turning control method comprising: a moving process in which the pivot turning or swivel turning in the turning process is temporarily interrupted each time the tracked vehicle turns by a predetermined divided angle, and the left and right crawlers are controlled to move the tracked vehicle forward or backward by a predetermined distance.

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