JP2024004977A - Work machine - Google Patents

Abstract

To solve the problem in which: positioning alignment is performed before work by slip-moving a work machine in correspondence to positional deviation, a range in which work cannot be performed just after starting work is eliminated, and loads are not applied to a farm field and the work machine in positioning alignment is performed, when an inertia coordinate system detected by a reception section device and an inertia measurement device of a GPS is positionally deviated from an absolute coordinate system by latitude and longitude on the ground.SOLUTION: Positions in an inertia coordinate system calculated by a reception section device and an inertia measurement device of a GPS and in an absolute coordinate system detected by sensing imaging means and preliminarily registered latitude and longitude information on the ground are made to coincide with each other by an equation of motion by a coordinate conversion method in a rotary system. Rotational speed of single-wheel or two-wheels of four-wheels is made different from that of other wheels, and four-wheel steering is performed while slipping the wheels and a ground section. Thus, positional deviation is corresponded.SELECTED DRAWING: Figure 1

Description

The present invention relates to a work machine that enables automatic operation with high precision in agriculture.

An invention has been described that improves detection accuracy in automatic driving and deals with deviations in detected positions.However, in order to deal with position deviations in a short time at the start of work without any work loss, it is necessary to improve the running mechanism and steering control of work equipment. No description has been made. (Patent Document 1)

JP2020-164160A

In the above-mentioned conventional technology, there is a description of calculating positional deviation and azimuth deviation as a response to positional deviation of a running vehicle, but the running vehicle itself does not have a steering method or a driving method to cope with positional deviation. There is no particular description of the dedicated support for the mechanism. In the present invention, it becomes possible to control positional deviations such as positional deviation deviations in a short period of time and for a short work travel distance of a traveling vehicle, or to perform positional deviation countermeasures before traveling for work.

The first invention is solved by the following technical means.

The vehicle is equipped with a four-wheel drive and four-wheel steering system, and there is a misalignment between the vehicle's position on the travel line in the preset direction of travel 600 and the vehicle's position calculated by the GPS receiver and inertial measurement device. When the rotation speed of one or two of the four wheels is different from the rotation speed of the other wheels, and the movement is accompanied by slippage between the wheels and the ground contact area, the rotation speed in the traveling direction 600 While aligning the axle 610, misalignment is automatically dealt with.

The second invention is solved by the following technical means.

If the direction of travel 600 and the front and rear axles 610 exceed predetermined values after the positional deviation has been corrected, and control is performed to adjust the directions, the rotation speed of one or two of the four wheels may be set to a rotation speed that is different from the rotation speed of the other wheels. If the traveling direction 600 and the front and rear axles 610 fall within a predetermined value, the rotational speed of the four wheels will be the same rotational speed by performing slip movement while performing four-wheel steering while slipping the wheels and the ground contact area. Automatically controls the direction to return to.

The third invention is solved by the following technical means.

The coordinate system of the own vehicle position calculated by the GPS receiving device and the inertial measurement device, the position of the coordinate system detected by the imaging means for sensing and the latitude and longitude information on the ground registered in advance, and the coordinate system of the rotation system Match based on the equation of motion using the conversion method,
While driving based on this matched position, set the rotation speed of one or two of the four wheels to be different from the rotation speed of the other wheels, and perform four-wheel steering while performing slip between the wheels and the ground contact area. conduct,
The coordinate system of the own vehicle's position calculated by the GPS receiving device and the inertial measurement device is matched with the position of the coordinate system detected by the imaging means for sensing, and also in the direction of travel 600 and the direction of the front and rear axles 610. After that, the vehicle automatically changes the speed of rotation of all four wheels to the same speed.

The fourth invention is solved by the following technical means.

The coordinate system of the vehicle's position calculated by the GPS receiver and inertial measurement device and the position of the coordinate system detected by the imaging means for sensing and the latitude and longitude information on the ground registered in advance are converted into a rotational system coordinate system. Match based on the equation of motion according to the law,
While driving based on this matched position, using two-wheel steering, the coordinate system of the vehicle's position calculated by the GPS receiving device and inertial measurement device and the coordinate system detected by the imaging means for sensing are The traveling speed is set so as not to increase above a predetermined speed until the positions match, and when the traveling direction 600 and the front and rear axle 610 directions match, the traveling speed is increased to the set speed.

The fifth invention is solved by the following technical means.

A low-voltage battery 120 is provided at the front of the aircraft, and a high-voltage main battery 130 and an electric motor 140 are arranged in parallel in the front-rear direction behind it.
An HST (hydraulic continuously variable transmission) 150 is provided on the rear side of the vehicle body of the electric motor 140. Power is input from the electric motor 140, and the power is distributed from the output shaft of the HST 150 to the axle 190 of the traveling system and the hydraulic pump 200, and the surplus of the HST 150 is A regeneration motor 550 is provided for regenerating power, and the low voltage battery 120 is charged by the regeneration motor 550.

In the first invention, since lateral movement and rotational movement about the center position of the vehicle body are also possible, it is possible to perform positional alignment at the starting position almost without traveling.

In the second aspect of the present invention, even though the position of the machine has been adjusted, it is possible to perform direction control when there is a misalignment between the traveling direction 600 and the front and rear axles 610 after starting work. Similar to the first invention, it is possible to move laterally and rotate around the center position of the vehicle body, so it is possible to respond to misalignment at an early stage, and when it is confirmed that there is no misalignment, it automatically slips. Since the machine automatically runs after completing the process, the load on the field and working equipment is also reduced.

In the third invention, when the coordinate system of the own vehicle's position calculated by the GPS receiving device and the inertial measurement device and the position of the coordinate system detected by the imaging means for sensing are misaligned, the relationship of the misalignment is determined using a rotational system. By matching based on the equation of motion using the coordinate transformation method, positioning can be performed while taking into account the detection error of the coordinate systems calculated by each method.

In the fourth aspect of the invention, when dealing with misalignment in a two-wheel drive vehicle, lateral movement or the like is not possible, so the distance traveled until the misalignment is resolved becomes longer. By not increasing the traveling speed during this time, positioning can be achieved in a short traveling distance.

The fifth invention is that when the output to the HST decreases, power loss occurs, so when the output load from the HST is small, the output is connected to the regenerative motor to recover energy and reduce power loss. be able to. Charging the low voltage battery is effective in protecting the control system of the robot working machine.

A perspective view of a work machine with the exterior removed in an embodiment of the present invention An enlarged perspective view of a work machine with the exterior removed in an embodiment of the present invention A diagram related to the electrical system of a work machine in an embodiment of the present invention Diagram of correcting positional deviation before work of the present invention by slip lateral movement Diagram of adjusting the positional deviation before work of the present invention by slip lateral and backward movement A diagram of adjusting the positional deviation before work of the present invention by slip turning movement A diagram of adjusting the misalignment of the present invention by slip turning movement while traveling Diagram of adjusting the positional deviation of the present invention by spin turn of slip rotation movement Diagram showing how to correct the positional deviation of the present invention using slip turning and braking Flowchart for correcting GPS position coordinates Rotational motion diagram in the inertial and absolute coordinate systems Diagram of the relationship between space and time in the inertial coordinate system and absolute coordinate system Equation of motion diagram of space and time by coordinate system alignment of inertial coordinate system and absolute coordinate system Steering peripheral diagram of the present invention Operation diagram of the steering actuator of the present invention Control-related diagram of the present invention Engine mounting diagram of the present invention

The present invention will be described below based on embodiments shown in the drawings.

The working machines shown in FIGS. 1 to 17 are examples of the working machines of this embodiment.

The flow of power transmission according to the present invention will be explained.

As shown in FIGS. 1 and 2, inside the hood 110 at the front of the machine, there is a low voltage battery 120 in the left and right direction at the front of the machine, and a high voltage main battery 130 behind it in the front and back direction. An electric motor 140 is provided next to the main battery 130 in the front-rear direction and serves as a power source for operating the machine body and working equipment using the power of the main battery 130.

The low voltage battery 120 serves as a power source for the driver's seat display 330 and the controller 331 of the work machine. It is a controller that controls driving and work, external communication, and registers data on each operating state. It is an auxiliary battery, and is a low voltage battery such as a 12V battery. Normally, when a high voltage battery is also provided at the same time, the low voltage battery is charged by converting the voltage from the high voltage battery, but in the present invention, as shown in FIG. 3, a low voltage battery 120 and a high voltage main battery 130 are used. are independent, and the low voltage battery 120 is charged as regenerative electricity by the regenerative motor 550 from the surplus power of the HST 150. Further, the voltage of the high-voltage main battery 130 is managed by the MDU 131, and the electric motor 140 is controlled.

The electric motor 140 is equipped with an external fan 141 at the rear end of the motor, which is linked to the motor shaft. When the motor is in operation, the wind generated by the external fan 141 protects the motor, low voltage battery 120, and main battery 130. Air cooled. The hot air is discharged to the outside from the grill mesh section 111 in front of the hood 110 or from the front lower part of the hood. Further, the hood 110 is configured to completely cover the electric motor 140, the low voltage battery 120, and the main battery 130, thereby making the hood 110 weatherproof against rain and car washes, and is also appropriately dustproof.

As shown in FIG. 2, the electric motor 140 has an output shaft on the rear side in the longitudinal direction of the vehicle body, and is electrically driven to an HST 150 provided at the rear thereof. The transmission method may be to connect pulleys provided on each shaft with a belt, or may be to directly connect the electric motor 140 and the HST shaft. In the case of belt drive, the axis of the electric motor 140 and the input and output shafts of the HST 150 are in parallel directions, and as a power mechanism, they are serial and transmit power without bending, so there is little loss and a compact arrangement is possible. Can be formed.

In FIG. 17, the output shaft of the electric motor 140 is placed at the rear of the vehicle body and connected to the HST 150, thereby making it easy to be compatible with the engine 650 configuration. By disposing the heavy main battery 130 and electric motor 140 in the hood 110 and making the weight close to that of the engine 650, the configuration is such that there is no difference in balance between the specifications of the electric motor 140 and the specifications of the engine. By removing the BMS and the inverter 160 from the hood 110 and placing it behind the seat 170, it becomes possible to improve maintainability and deal with heat build-up. Also in this configuration, the low voltage battery 120 is charged as regenerative electricity by the regenerative motor 550 from the surplus power of the HST 150.

As shown in FIG. 3, the BMS (battery management system) manages the high-voltage main battery 130, and receives commands from the control unit 180 and performs voltage management, etc. according to the control. There is. The inverter located at the same location is also called MDU and controls the rotation speed of the electric motor. In this proposal, the BMS and inverter 160 are integrated and placed at the rear of the seat for easy maintenance, and can also handle heat build-up and dust. Depending on the configuration, the BMS and the inverter (MDU) may be located at different locations.

With this arrangement, the electric motor 140 may rotate continuously at a fixed rotation speed, or may be controlled by an inverter so that the rotation can be varied according to the required power. In the embodiment of the present invention, the system controls the rotation speed of the electric motor 140 while managing the high voltage main battery 130 via the BMS and the inverter 160 in response to commands from the control unit 180 of the machine. . Because of this system, even when the machine stops traveling and the work equipment is also stopped, the rotation of the electric motor 140 is reduced to the extent that the reference oil pressure of the HST 150 can be generated.

The mechanism after HST150 of the present invention will be explained.

Although it is less power loss for the HST 150 to directly receive the rotation of the electric motor 140, the electric motor 140 is housed in the front hood 110 and the heat is exhausted using the external fan 141 attached to the electric motor 140. , it is necessary to arrange it at the center of the hood 110 in the height direction. Also, in order to prevent the HST150 from burning out, it is necessary to radiate heat to the outside air. Although it would be effective to provide a dedicated fan or the like, in order to achieve a compact configuration, the HST 150 is mounted below the main body frame so as to be open to the outside air.

For this reason, since the electric motor 140 and the HST 150 are misaligned in their vertical positions, power is transmitted through the belt 141. However, since they are connected in series, there is little power loss. Similarly, as shown in FIG. 3, the axle 190 of the traveling system, the hydraulic pump 200, and the air compressor 210 are arranged in series, so that the configuration including the work equipment has little power loss.

In this way, the power system is arranged in series from the electric motor 140 to the air compressor 210, and is arranged by electric belts on the top, bottom, left and right sides to cope with heat trapping. Further, by disposing the air compressor 210 above the working machine 220, it is possible to create a configuration in which damage due to dust does not occur during suction.

The regenerative motor 550 will be explained.

The rotation speed of the electric motor 140 can be controlled by the BMS and the inverter 160, but since the traveling speed and the rotation speed of the PTO 230 are changed using the HST, the electric motor 140 is fixed at a high rotation speed during work. state. Therefore, if the traveling speed is reduced during work or the output of the PTO 230 is reduced, surplus power will be generated in the HST 150 because it receives the full power from the electric motor 140. In some cases, the HST 150 internally uses relief power to prevent the oil temperature from rising, but in the present invention, when the output to the HST 150 running system or the output of the PTO 230 decreases, the power is transmitted to the regenerative motor 550. By doing so, it is possible to cope with surplus power to the HST. The HST 150 has a power output shaft 151 to the regenerative motor 550, from which power is input to the regenerative motor 550. The regenerative motor 550 is a motor for generating low voltage, and generates DC 12V to charge the low voltage battery 110.

As another embodiment, a system may be considered in which the regenerative motor 550 generates high voltage and the main battery 130, which is a high voltage battery, is charged with the regenerated electricity. In this case, the converter lowers the voltage, converts it to a low voltage, and charges the low voltage battery 120.

The recovery of regenerative electricity according to the fifth invention is that when the output of the HST decreases and surplus power is generated, the power is generated by a low-voltage regenerative motor and directly charged to the low-voltage battery 110. . This not only eliminates the need for a converter from a high voltage battery to a low voltage battery, but also prevents energy loss by converting the voltage from high voltage to low voltage using a converter, and by eliminating the exchange of electricity between batteries again. be.

In this way, the fifth invention shows the characteristics of a work machine that enables automatic operation. Slip movement involves a large load, and the HST, which is the power for the traveling system, must be configured to stably and immediately output power. Therefore, it is necessary to input power to the HST above a certain rotation speed. Furthermore, although the BMS issues a command to change the rotation speed of the electric motor, the electric motor is often kept at a high rotation speed because it cannot immediately respond to the speed change of the HST. In other words, with the mechanism that transmits power from the electric motor to the HST or hydraulic pump, it is difficult to precisely control the rotation speed of the electric motor to prevent power loss, and surplus power must be recovered from the output of the HST or hydraulic pump. method is preferred.

If the output to the HST decreases in this way, power loss will occur, so if the output load from the HST is small, connecting the output to the regenerative motor can recover energy and reduce power loss. . Furthermore, charging the low-voltage battery is effective in protecting the control system since it is a robot working machine.

The hydraulic pump 200 of the present invention will be explained.

Rotational power is obtained from the output shaft of the HST 150 to operate the hydraulic pump 200, which in turn operates the hydraulic actuator 260. The hydraulic actuator 260 is connected by a hydraulic piping 270. Although the present invention is an embodiment in which the motor is operated by an electric motor 280, a configuration in which a small hydraulic motor is used is also possible. In the present invention, the hydraulic pump is operated by receiving power from the output shaft of the HST, but as another embodiment, the hydraulic pump may receive power directly from the electric motor 140.

The air compressor 210 of the present invention will be explained.

An air compressor 210 is installed under the seat 170 via the output of the HST 150. By placing it above each working machine in this machine, it is possible to sort out dust and dirt by weight during suction. The pressurized air generated by the air compressor 210 can be used for suction work by using an air nozzle, or for operating a working machine by using an air cylinder.

The operation section of the driver's seat display 330 will be explained.

When driving manually, the remaining battery capacity, vehicle speed, main and auxiliary gear settings, GNSS sensitivity, the status of the vehicle's driving line and target line, and the fuel gauge in the case of engine specifications are displayed. You can set conditions on the 330 and use each lever and dial. These same functions can also be displayed and set using the remote control.

The work system operating device 340 will be explained.

It is possible to operate the work machine using the operating device 340 on the right side of the driver's seat. The operating device 340 is equipped with a large display, which displays images taken by the imaging means A410, B411, C412, and D413, and allows operation and settings of the working machine. The settings screen on the display and the roles of the control levers and control switches change depending on the work equipment installed.

Explain automatic driving and manual driving.

This machine is a robot working machine 100, and is capable of automatic operation with the contents set and registered in advance. It can also be operated remotely using a remote control.

This machine is equipped with a LOPUS 300 behind the seat 170 to prevent falls, and the top end of the LOPUS 300 is also equipped with a GPS receiver 310 and an inertial measurement device IMU 320 for confirming and correcting the position of the machine. There is. By using this receiver, the device can accurately determine the vehicle's location, making autonomous driving possible.

Further, the robot working machine 100 can be operated manually while riding on the robot. The central part of this machine is equipped with a seat 170 and a steering wheel 171 so that a person can drive the machine, and when the driving operation device 175 detects movement, the driving mode is switched, and it is possible to drive the machine with a person sitting in the seat. It is.

Basic positional shift handling and automatic steering of the robot work machine 100 will be explained.

The GPS receiving device 310 and the positioning unit, which is a positioning method, are composed of a mobile station provided at a positioning satellite and a base station provided at a known position. Thereby, the position of the mobile station, that is, the position of the work implement, can be accurately obtained from the position information transmitted from the positioning satellite to the mobile station and the correction position information transmitted from the base station to the mobile station.

The base station is comprised of a fixed communication device, a GPS receiver 310 that receives position information from positioning satellites, and a fixed data transmission antenna that transmits correction position information to the mobile station.

The mobile station includes a mobile communication device, a mobile GPS receiver that receives position information from a positioning satellite, and a mobile data transmission antenna that receives correction position information from a base station. The control unit 180 of the work machine is formed of a processing unit including a CPU, a storage unit including ROM, RAM, hard disk drive, flash memory, etc., and a communication unit for data communication with the outside.

For the GPS receiving device 310, it is preferable to use a method suitable for the area where work is to be performed, such as a single positioning method, a DGPS (relative positioning) method, or an RTK (interferometric positioning) method. However, if the ground height of the GPS receiver 310 changes due to the influence of the aircraft's tilt or vibration, a coordinate position different from the actual aircraft position will be measured, reducing reception accuracy and causing the aircraft to travel in a direction that deviates from straight ahead. A problem arises. In order to prevent this, in addition to the GPS receiving device 310, an inertial measurement device IMU 320 is provided. The inertial measurement device IMU 320 is based on the difference between the height from the ground surface to the GPS receiving device 310 when the robot working machine 100 is in a tilted position and the height from the ground surface to the GPS receiving device 310 when the robot work machine 100 is not tilted. , the control unit 180 corrects the position coordinates acquired by the GPS receiving device 310.

Note that the height from the ground surface to the GPS receiving device 310 is determined by measuring the behavior of the robot working machine 100, such as inclination, using a triaxial acceleration sensor and an angular velocity sensor built into the inertial measurement device IMU 320. . In addition to this, a direction sensor 311 is provided to allow the control unit 180 to more reliably determine whether the direction in which the aircraft is traveling by the automatic straight-ahead system is correct. Correction of the position coordinates at this time is as shown in SS1 to SS5 in FIG. 10. This allows the aircraft's course to be determined based on the measured direction, further improving the accuracy of straight travel.

The position information acquired by the GPS receiving device 310 is corrected by the control unit 180 based on information detected by the inertial measurement device IMU 320 and the orientation sensor 311. Then, the control unit 180 compares the current position information with the previously acquired position information, and if the difference in position information exceeds the allowable range, the control unit 180 adjusts the left front wheel 560 to return the aircraft to the straight-ahead running position. The right front wheel 570 is steered in the left-right direction.

In order to automate the steering of the left front wheel 560 and the right front wheel 570, an automatic steering device 172 is provided that rotates a steering wheel 171 with a steering actuator 173. The automatic steering device 172 performs steering operations based on the difference between the X coordinate of the current position information calculated by the control unit 180 and the X coordinate of the previously acquired reference position information, as shown in SS6 to SS9 in FIG. By varying the operating amount of the actuator 173, the steering wheel 171 is turned left and right to direct the aircraft to the straight-ahead position, and when the aircraft reaches the straight-ahead position, the steering actuator 173 is stopped and the automatic steering 172 of the steering wheel 171 is activated. It is something that makes it stop.

The steering actuator 173 is composed of an electric or hydraulic motor or a cylinder. With the above configuration, the steering wheel 171 is automatically steered according to the difference in the X coordinate of the calculated position information, and the aircraft can be automatically aligned to the straight-ahead traveling position, so that the work position of the work device can be adjusted in the left-right direction. Misalignment is prevented, and it is less likely that there will be areas in the field where work is not performed. This eliminates the need to manually perform work on areas where no work has been done afterwards, reducing the labor of the worker.

The vehicle position and inertial coordinates calculated by the GPS receiver and inertial measurement device will be explained.

In the robot working machine 100, control is performed to superimpose the coordinates of the GPS receiving device 310 with the east-west direction as the X-axis and the north-south direction as the Y-axis, as the coordinate position of the own vehicle. Also, the coordinates of one side of the field, which is the starting point of the automatic straight-ahead movement of the robot working machine 100, and the coordinates of the other side of the field, which is the end point of the automatic straight-ahead movement of the robot working machine 100, are acquired.

With the first reference point A601 obtained, the second reference point B602 is obtained, and this straight line becomes the traveling direction 600. If the front and rear axles 610 of the own vehicle, so-called direction lines, are inclined with respect to the traveling line heading in the traveling direction 600, the direction is changed as shown in FIG.

The first reference point A 601 and the second reference point B 602 are relocated to predetermined positions at one end and the other end of the field, for example, the position where the work equipment starts turning after finishing straight traveling and the position where straight traveling starts after completing turning. Set and drive straight.

As mentioned above, when the first reference point A601 and the second reference point B602 are newly acquired, the reference line connecting the respective Y coordinates of the first reference point A601 and the second reference point B602 is set to be relocated. This is a line that serves as a guide for automatic straight-ahead travel, and it is determined whether the X coordinate of the position of the moving aircraft matches the X-coordinate of the line that serves as a guide for automatic straight-ahead travel.If it does not match, the automatic steering system By automatically steering the steering wheel 171 in a direction that is more consistent with the steering wheel 172, automatic straight-ahead driving can be realized. The control unit 180 compares the Y coordinate of the position coordinate acquired by the GPS receiving device 310 with the Y coordinate of the reference line, operates the steering actuator 173 to rotate the steering wheel 171 in the left and right direction, and moves the robot working machine 100 straight. Control to move the vehicle to the desired position is started. This automatic steering ends when the steering wheel 171 is operated to an angle that turns the traveling vehicle body within a predetermined time, or when the automatic straight-ahead setting member 207 is operated in the second direction. The steering angle of the steering wheel 171 is detected by a handle potentiometer 172. When the traveling vehicle body 2 reaches a location that matches the Y coordinate of the first reference point A or the second reference point B, the automatic straight-ahead control may be terminated and the turning control may be started.

In this embodiment, the positional information of the reference line is acquired for each work process, and the positional information of the target line in the next process of the work process is determined each time. As a result, the deviation of the reference line can be minimized, the deviation of the target line in the next work process can be reduced, and the line alignment in the automatic turning process can also be carried out.

There may be deviations in the reference line over time or due to the influence of clouds, etc., so by acquiring a new reference line for each work process as described above, it is possible to eliminate deviations in the reference line. It is possible to minimize the deviation of the target line in the next planting work process, and it is also possible to perform row alignment in the automatic turning process.

Four-wheel drive four-wheel steering driving will be explained.

This work machine is four-wheel drive and allows four-wheel steering. The left front wheel 560, the right front wheel 570, the left rear wheel 580, and the right rear wheel 590 are arranged, and each wheel 560, 570, 580, and 590 rotates by receiving power from the same HST 150, but the power transmission path In this system, individual speed changes are performed for each shaft, and the rotational speed can be changed individually using planetary gears in the final case of each wheel. It is also possible to apply the brakes on each wheel individually using electronic control.

Additionally, each wheel can be steered by an individual link. In the present invention, individual electric gear motors are provided for each axle as a front left motor 561, a front right motor 571, a rear left motor 581, and a rear right motor 591, and the rotation is controlled by the control unit 180. ing. Potentiometers 562, 572, 573, and 574 are provided on each axle to individually detect the steering angle. If the detected angle differs from the steering angle instruction given by the control unit 180, each electric gear motor is operated.

4 to 9 show embodiments of the first invention.

With this invention, as mentioned above, this machine is capable of automatic operation, and the rotation speed of the four wheels can be changed independently, and the direction of the four wheels can also be changed independently, so it can move laterally and the center position of the car body can be changed independently. Rotational movement is also possible. With a two-wheel steering mechanism, if a positional shift is detected, the position must be gradually adjusted while the vehicle is running. However, if the positional deviation exceeds 1m, there will be areas that cannot be worked on by positioning while driving, so it is necessary to adjust the position by switching between forward and backward movement and steering before starting work. However, there were cases where the farmland was damaged. In the present invention, since lateral movement and rotational movement about the center position of the vehicle body are also possible, it is possible to perform positional alignment at the starting position almost without traveling.

I will explain how to drive. The first reference point A601 and the second reference point B602 described above are acquired, and a travel line is determined. Further, the vehicle position calculated by the GPS receiving device and the inertial measurement device is an inertial coordinate.

In automatic driving, the position deviation between the position detected by inertial coordinates, the position according to the driving line obtained by acquiring the first reference point A601 and the second reference point B602, and the own vehicle position calculated by the GPS receiving device and inertial measurement device This is to adjust the traveling direction and position while also performing control to match the traveling direction 600 and the front and rear axles 610.

FIG. 4 shows a case where, although the orientation is the same with respect to the traveling direction 600, the own vehicle center position 611 is not on the traveling line of the traveling direction 600 and is displaced. With the conventional technology, this positional shift is adjusted while the vehicle is running. Therefore, even if the directions match, the system allows the direction to be changed and changes the direction within a predetermined range to adjust the position, and gradually adjusts the position to within the traveling direction line while driving. be. In this type of position alignment, there will be parts that cannot be worked on until the vehicle matches the travel route.

There would be no problem if the system simply operated along a travel route, but the present invention is a working machine, and if there is a part that cannot be worked on, that part must be repaired again. In order to deal with this inconvenience, it is sufficient if the positioning can be performed by moving the position without running, if possible, instead of gradually aligning the position by driving.

As shown in FIG. 4, if the position is shifted parallel to the left side with respect to the traveling direction 600, the left front wheel 560 and the right front wheel 570 are turned to the left side. The left rear wheel 580 and the right rear wheel 590 are steered to the opposite side from the front wheels. In this case, the front wheels are on the left, so turn the steering to the right. In addition, the left front wheel 560 and the right front wheel 570 are assumed to rotate rearward, and the left rear wheel 580 and right rear wheel 590 are assumed to be rotated forward.

In other words, the steering direction and traveling direction are set to the right from the center of the vehicle body. Through this steering and wheel rotation control, the vehicle body moves as if the front and rear wheels are pushing against each other, allowing the vehicle body to move in parallel to the right while slipping between the wheels and the ground contact area. This makes it possible to control the positioning by parallel movement without traveling or changing the direction of objects whose directions match.

In FIG. 5, although the directions match, there is a positional shift, and lateral movement and rearward movement are required. In this case, the front and rear wheels may be steered in the same direction to move diagonally. If the distance of positional deviation is long, such a diagonal movement method is better, but if the distance is minute, it may go too far, and switching and steering at this time may damage the field. Therefore, the slip running shown in FIG. 4 is used. The difference in the length of → shown in the figure indicates the difference in the number of rotations of the wheels. In this figure, the left front wheel 560 and the right front wheel 570 are turned to the left, and the rotation speed is set to be fast for backward rotation. Further, the left rear wheel 580 and the right rear wheel 590 are turned to the right side, and the wheels rotate forward, but the rotation speed is set to be slow. This causes the vehicle body to gradually move diagonally backward in parallel. While observing the positional deviation, we respond by changing and controlling the rotation speed of the front and rear wheels. For example, if it is determined during movement that the rearward movement is insufficient, this can be countered by further reducing the rotational speed of the left rear wheel 580 and the right rear wheel 590.

FIG. 6 shows a case where both direction and position are shifted. The vehicle is facing left in the direction of travel, and the vehicle body position is determined to be on the left and toward the front. In this case, the same control as in FIG. 5 is performed, but the difference is in the steering angles of the front wheels and rear wheels. By making the leftward steering angle of the front wheels larger than the rightward steering angle of the rear wheels to increase the amount of movement on the front side, rotational movement can be performed. This makes it possible to align the traveling direction 600 with the front and rear axles 610 while rotating backward, and also to align both coordinate positions.

In FIG. 7, a method of positioning while traveling will be explained. However, the positioning is not done gradually, but rather over a short distance while slipping, which is different from the prior art. In FIG. 7, the front and rear axles 610 are directed to the left with respect to the traveling direction 600, and it is determined that the vehicle body coordinate position is shifted to the left. All four wheels turn to the right, but since this involves rotational movement, the steering angle of the front wheels is increased and the rotational speed of the front wheels is also increased. In this case, position detection accuracy will vary due to positioning while the vehicle is running, so the front wheels will be flexibly steered for a while and will not enter fixed steering control for straight-ahead travel.

FIG. 8 shows spin control. With crawlers such as combine harvesters, this can be done by changing the left and right rotation directions, but with four wheels, the ground pressure is low, so it is impossible to slip and rotate in the field. Therefore, steering the four wheels in the same direction by changing the front and rear rotation speeds, or changing the rotation speeds of the left and right wheels, stopping the rotation of one wheel on the inside wheel that is the center of rotation, or extreme By lowering the wheel to a lower position, the wheel is rotated around the axis.

FIG. 9 shows vehicle body turning control using fixed wheels. In this figure, the brake is applied to the right rear wheel 590, and the left front wheel 560 and left rear wheel 580 are driven. The front wheel 570 only rotates as a result. This control enables direction change control with the right rear wheel 590 as the central axis.

4 to 9 show typical movements of slip running. The basic idea is to cause slippage by changing the rotation speed of one or two of the four wheels. While it is difficult for a car or other vehicle to slip on asphalt, it is easy for a working machine that works on the soil in a field to slip, and by combining four-wheel drive and four-wheel steering, it is possible to move the position without traveling for work. By doing this, there is a control system that allows you to immediately start good automatic operation by taking measures against positional deviations before starting work. Rather than aligning while working, the robot can be operated without missing any work because it can be aligned before starting work.

As for the second aspect of the invention, if positional deviation control reacts to even minute differences, slip running must be performed at all times, and conversely, malfunction may occur. As a method for dealing with this, it is necessary to provide a range for dealing with positional deviations. A predetermined angle is set for the direction angle, and if it falls within this range, positional deviation detection continues, steering control is performed, but the rotational speed of the four wheels is kept at the same rotational speed, and slip running due to the difference in the rotational speed of the drive wheels is stopped. It is something. This eliminates running loss, allows stable straight-line driving, and improves fuel efficiency. The fact that no load is applied to the working machine itself is also advantageous in terms of consumable parts and the like. In this way, slip driving is highly effective, but it also has risks, and by incorporating early response and early release controls, automatic driving control can be used stably.

The coordinate system of the vehicle's position calculated by the GPS receiver and inertial measurement device and the position of the coordinate system detected by the imaging means for sensing and the latitude and longitude information on the ground registered in advance are converted into a rotational system coordinate system. A third invention in which matching is performed based on an equation of motion according to the method will be explained.

This invention uses an inertial coordinate system calculated by a GPS receiving device and an inertial measurement device, and an absolute coordinate system detected by an imaging means for sensing and latitude and longitude information registered in advance on the ground as a rotating system. Matching is done based on the equation of motion using the coordinate transformation method, the rotation speed of one wheel or two wheels is set to a rotation speed different from the rotation speed of the other wheels, and four-wheel steering is performed while slipping between the wheels and the ground contact area. We respond by doing things.

First, the inertial coordinate system will be explained. The GPS receiving device 310 uses a method suitable for the area where work is to be performed, such as a single positioning method, a DGPS (relative positioning) method, or an RTK (interferometric positioning) method. However, no matter which method is used, when the earth is used as the coordinate reference, there is an offset amount in the measured coordinates. In order to correct the amount of offset, corrections are made using information from multiple satellites and position information from base stations on the ground.

As an existing technology, there is an invention that corrects position information using an inertial measurement unit IMU 320 instead of information only from a satellite. However, the inertial measurement device can be calculated by measuring forces such as yaw rate when the robot work machine 100 moves, and when it is stopped, it can only detect obstacles, etc. It does not play a role in correcting position detection.

In the present invention, the positional shift is dealt with while the machine is stopped at the start of the work. The inertial measurement device IMU 320 is not fully functioning and cannot sufficiently correct the coordinate system of the GPS reception device 310 based on data from the satellite. The coordinate system of the own vehicle position calculated by the IMU 320 is defined as an inertial coordinate.

Next, the absolute coordinate system will be explained. In the robot work machine 100, the control unit 180 has field position data 621 in which the coordinate system of the field to be worked on and the work start position of the field is registered in advance. It is registered as an absolute position on the earth's surface based on latitude and longitude. As field data, the absolute position coordinates of several locations such as work start positions and reference positions are registered as coordinate numerical data, and it is also possible to register and read data as field map data. In some cases, by pressing the target position on the map from the field position selection terminal 620, the absolute coordinates of the reference point of each field can be read out.

The robot work machine 100 is also equipped with imaging means B411, C412, and D413. This video is used to check crops in the field and nearby obstacles, but it also has a function that allows you to check the direction. Images captured by the imaging means B411, C412, and D413 at positions determined in advance as work start positions are registered. The control unit 180 has a function of calculating the orientation shift from the arrangement and area of the shaped object in the image photographed in advance. In the robot work machine 100, the amount of movement of the machine body is determined while comparing the images taken by the imaging means B411, C412, and D413 with the images registered in advance.

In the absolute coordinate system, the offset amount of the initial absolute coordinate position is corrected using the coordinate reference of each field based on the earth and the coordinate reference based on image matching by the imaging means. This coordinate position is more accurate than the position calculated from the GPS receiving device 310, and can be used as absolute coordinates.

On the other hand, the accuracy of the position data of the GPS receiving device 310 is improved by correction by the inertial measurement device IMU 320. Although there is a large error at the work start position in the field where no movement is involved, this coordinate is used as the inertial coordinate to align with the absolute coordinate.

In this way, there are two types of coordinate positions: absolute coordinates and inertial coordinates. Furthermore, the absolute coordinates in this proposal are field positions registered in advance, and are accurate at that point in time, but once the work vehicle starts traveling, even if the absolute coordinates are set, there is a heavy reliance on inertial coordinates. If the absolute coordinates and inertial coordinates can be aligned at the work start position, including these problems with the conventional technology, the subsequent positional deviation will be caused by the offset inherent in the GPS receiving device 310 and the position defined as the absolute coordinates. Since it is only a quantity, it is expected that the accuracy of position calculation will be high.

In order to solve these problems, the present invention moves the robot work machine 100 so that the absolute coordinates and the inertial coordinates are aligned at the work start position at the time of starting the work. As a match between the absolute coordinates and the inertial coordinates, the inertial coordinates are used as virtual coordinates, and control is performed to match them with the absolute coordinate system. As a measure, the robot working machine 100 adjusts the coordinates while slipping.

The actual positional deviation between the inertial coordinates and absolute coordinates of the GPS receiving device 310 is often on the order of several centimeters to several tens of centimeters, and since the positional deviation does not exceed several meters, slight lateral This can be dealt with by moving. In fact, it can be said that the deviation in direction is larger. Taking this into account, we apply a logic that prioritizes orientation alignment and uses rotating system coordinate alignment, which can deal with positional deviations. This is the logic of aligning absolute coordinates and inertial coordinates with the starting points of the X-axis and Y-axis, and adjusting mutual deviations.

In FIGS. 11 and 12, as a measure to match absolute coordinates and inertial coordinates, control is performed to match them based on an equation of motion using a coordinate transformation method of a rotating system. The coordinates of the GPS receiving device 310 are superimposed on the absolute coordinate system, with east-west as the X-axis and north-south as the Y-axis. Calculate the axis deviation angle of the inertial coordinate system, estimate the amount of spatial movement in a predetermined time from the movement speed and slip rate from the current position, and calculate the estimated time to the matching position and the X-axis of the robot working machine 100 at that position. By calculating the movement speed of the Y axis, the steering direction and movement speed of the initial movement of the robot working machine 100 are determined.

This logic is applied because position information from satellites is used for both what is defined as absolute coordinates and what is defined as inertial coordinates, and there is at least a small amount of offset from ground coordinates. This is because there is. Therefore, the method is to internally eliminate the amount of offset each has while aligning the positions of both. Therefore, it is not a means to numerically calculate the difference between the absolute coordinates and the inertial coordinates and perform positioning while measuring the moving distance of this difference. In simple terms, the robot working machine 100 received rotational energy, caused a sideways slip, and moved to the target position. This sideslip has velocity in the X and Y axes, but sliding friction is working between it and the ground surface, and an equation of motion is created that assumes that the robot moves while being influenced by this, and the steering of the initial movement of the robot working machine 100 is performed. The direction and speed of movement are determined, and the movement in space and time is considered to match.

FIG. 11 shows the equation of motion based on the coordinate transformation method of the rotating system described above. The position indicated by X and Y in the coordinate system is the absolute coordinate system. Further, the coordinates indicated by X' and Y' are inertial coordinates.

Currently, the robot work machine 100 is detected at p(x, y), and a positional deviation is detected at an angle of ωt between the absolute coordinate system and the inertial coordinate system. In this case, in order to align both the absolute coordinate system (X, Y) and the inertial coordinate system (X', Y') using rotational coordinates, calculation can be performed using the respective conversion formulas (S1, S2).

Further, it is assumed that the robot work machine 100 of p(x, y) operates by a movement amount F as a moving movement for position alignment, and it is defined that movement amounts Fx and Fy occur at each coordinate. In order to capture this amount of movement as a change over time and to manage and control movement based on time, we define an equation of motion based on time. The present invention uses a method of aligning the inertial coordinate system. (S3, S4) m shown in this equation corresponds to the weight used when the robot work machine 100 moves, and ω is the angular velocity in the X-axis and Y-axis. In other words, it means moving while slipping due to sliding friction on each axis.

FIG. 12 shows the logic for estimating the locus of change in space equivalent (distance) and time equivalent, assuming that absolute coordinates and inertial coordinates are made to match. S5, S6, S5a, S5b
This is a logic that compares the amount of change corresponding to space (distance) and time equivalent to the original n, and combines the amount of change of n+1.

In FIG. 13, S7 and S8 are defined as equations for changing minute changes in Δt. S9 and S10 are calculated by using this minute change as the directional component at Fx' and Fy'. By using this equation of motion, it is possible to estimate temporal changes in sideslip travel.

By adding the initial velocity in the X and Y directions due to slip running to the logical equations of S9 and S10, and establishing the equation of motion by taking into account the slip rate, and using the Runge-Kutta method etc. in the coordinate transformation equations of S1 and S2, , performs calculations to match the absolute coordinates and the inertial coordinate system.

Through calculation analysis, the steering direction, wheel rotation speed, and travel time are calculated, so positioning can be achieved by moving in this direction for a predetermined period of time.

The coordinates that match through this control are re-registered as absolute coordinates, and in subsequent operation of the work equipment, the coordinate system of the own vehicle position calculated from the GPS receiving device 310 and the inertial measurement device IMU 320 and the imaging means for sensing are used. The system performs automatic driving while making corrections based on the position of the coordinate system detected by the system.

In addition, the inertial coordinate system of the vehicle's position calculated by the GPS receiving device and the inertial measurement device matches the position of the absolute coordinate system detected by the imaging means for sensing and the latitude and longitude information on the ground registered in advance, By automatically changing the rotation speed of the four wheels to the same rotation speed when the direction of travel 600 and the direction of the front and rear axles 610 match, the robot work machine 100 may malfunction or go off the travel line again. This makes it possible to prevent problems.

Further, the present invention is not limited to four-wheel drive or four-wheel steering. As in the fourth invention, two-wheel drive and two-wheel steering can also be used. Although it is difficult to align while driving before work, the coordinate system of the vehicle's position calculated by the GPS receiver and inertial measurement device, the imaging means for sensing, and the latitude and longitude information on the ground registered in advance are used. By comparing the coordinate system positions detected in , it is possible to estimate the positional shift.

While driving with this matching position as a reference, using two-wheel steering, the coordinate system of the vehicle's position calculated by the GPS receiving device and the inertial measurement device and the image for sensing are captured. Positional deviations are handled until the coordinate system positions detected by the means match. Although it is not a control to deal with positional deviations before work, since positioning control is performed by slowing down the traveling speed until the positional deviations have been dealt with, it can respond more accurately than positioning control in the conventional technology.

The characteristics of two-wheel steering can be improved by setting the running speed so that it does not increase above a predetermined speed, and increasing the speed to the set speed when the direction of travel 600 and the direction of the front and rear axles 610 match. It is also possible to deal with misalignment.

100 Robot working machine 120 Low voltage battery 130 High voltage main battery 140 Electric motor 141 Outside fan 150 HST
160 BMS and inverter 180 Control unit 190 Traveling system axle 200 Hydraulic pump 210 Air compressor 220 Working device 310 GPS receiving device 320 Inertial measurement device IMU
410 Imaging means A
550 Regenerative motor 560 Front wheel left 570 Front wheel right 580 Rear wheel left 590 Rear wheel right 600 Traveling direction 601 First reference point A
602 Second reference point B
610 front and rear axles

Claims (5)

The vehicle is equipped with a four-wheel drive and four-wheel steering system, and detects the positional deviation between the vehicle's position on the travel line in the preset direction of travel (600) and the vehicle's position calculated by the GPS receiver and inertial measurement device. is occurring, one or two of the four wheels is rotated at a different speed from the other wheels, and the wheel and ground contact area slip. ) and the front and rear axles (610), and automatically adjusts for misalignment. If the direction of travel (600) and the front and rear axles (610) exceed predetermined values after the position shift has been corrected, and control is performed to adjust the direction, the rotation speed of one or two of the four wheels will be changed to the rotation speed of the other wheels. By setting the rotation speed to be different from the number of rotations and performing slip movement while performing four-wheel steering while slipping the wheels and the ground contact part, when the traveling direction (600) and the front and rear axles (610) are within the predetermined values, the four-wheel The work machine according to claim 1, wherein directional control is automatically performed to return the rotational speed of the wheels to the same rotational speed. The coordinate system of the own vehicle position calculated by the GPS receiving device and the inertial measurement device, the position of the coordinate system detected by the imaging means for sensing and the latitude and longitude information on the ground registered in advance, and the coordinate system of the rotation system Match based on the equation of motion using the conversion method,
While driving based on this matched position, set the rotation speed of one or two of the four wheels to be different from the rotation speed of the other wheels, and perform four-wheel steering while performing slip between the wheels and the ground contact area. conduct,
The coordinate system of the own vehicle's position calculated by the GPS receiving device and the inertial measurement device is matched with the position of the coordinate system detected by the imaging means for sensing, and the direction of travel (600) and the direction of the front and rear axles (610) are determined. 2. The working machine according to claim 1, wherein after the rotational speed of the four wheels is matched, the operating machine automatically changes the rotational speed of the four wheels to the same rotational speed. The coordinate system of the vehicle's position calculated by the GPS receiver and inertial measurement device and the position of the coordinate system detected by the imaging means for sensing and the latitude and longitude information on the ground registered in advance are converted into a rotational system coordinate system. Match based on the equation of motion according to the law,
While driving based on this matched position, using two-wheel steering, the coordinate system of the vehicle's position calculated by the GPS receiving device and inertial measurement device and the coordinate system detected by the imaging means for sensing are A claim in which the traveling speed is set so as not to increase above a predetermined speed until the positions match, and when the traveling direction (600) and the front and rear axles (610) match, the speed is increased to the set speed. 1. The work machine described in 1. A low-voltage battery (120) is provided at the front of the aircraft, and a high-voltage main battery (130) and an electric motor (140) are arranged in parallel in the longitudinal direction at the rear.
An HST (hydraulic continuously variable transmission) (150) is provided on the rear side of the vehicle body of the electric motor (140), power is input from the electric motor (140), and the output shaft of the HST (150) is connected to the drive system axle (190), According to claim 1, further comprising a regeneration motor (550) for distributing power to the hydraulic pump (200) and regenerating surplus power of the HST (150), and charging the low voltage battery (120) by the regeneration motor (550). Work equipment described.