JP7377379B2 - Wheeled agricultural robot with tread adaptive adjustment function and its adjustment method - Google Patents

Description

The present invention belongs to the technical field of agricultural machinery, and specifically relates to a wheeled agricultural robot having a tread adaptive adjustment function and an adjustment method thereof.

As the population increases day by day and contradictions in agricultural production with shortages of water resources, soil resources, and labor become more apparent, improvements in agricultural production efficiency are desperately needed. The use of agricultural robots to perform complex tasks in place of all or some people efficiently, safely, and reliably has become an inevitable trend in the development of agricultural mechanization.

For example, in China, the control of crop diseases, pests, and weeds has until now been the most labor-intensive, most labor-intensive, and most frequent work step during agricultural production; When spraying pesticides such as herbicides and liquid chemical fertilizers, there is not only a lot of waste but also serious harm to the environment, so smart field management robots have become a research hotspot in the industry. It is possible to perform detailed field management tasks such as fertilization, weeding, and crop information collection. When it comes to dosing/fertilization, smart field management robots adopt a precision spraying concept and use computer vision technology to detect weeds, followed by the directed spraying of herbicides, which are then used to grow crops. The amount of herbicide can be significantly reduced.

However, China's cultivated land has many hills and mountains, and when cultivating crops that are sown or transplanted by machinery, the precision of the machinery and the unevenness of the ground make it difficult for the cultivation rows to match. It disappears. Manned boom sprayers, intertill weeders, and conventional autonomous agricultural robots all have wheeled seedling holds. In many cases, a driver drives the implement along the crop row and an autonomous navigation robot adjusts the orientation of the chassis in real time based on the crop row, but these field management machines have the capability of tread adaptive adjustment. Ground obstacles such as protrusions and pits can cause the chassis to shake or make it difficult for small agricultural robots to pass through.

The present invention allows the tread of the robot to be adaptively adjusted according to the tread of the crop, which greatly reduces the pressure on seedlings during work, and also ensures that the chassis passes smoothly when encountering obstacles or narrow road sections. A technical object of the present invention is to provide a wheel-type agricultural robot having a tread adaptive adjustment function and a method for adjusting the same.

In order to achieve the above technical object, the technical solution according to the present invention is as follows.

A wheeled agricultural robot having a tread adaptive adjustment function, comprising a control system and a vehicle body provided with four drive wheel legs,
A tread adjustment actuator is further provided;
The four driving wheel legs of the vehicle body are each connected to the chassis frame through a corresponding rocker arm, and the driving wheel legs are equipped with wheels and a steering device, and each wheel is driven by an individual in-wheel motor, and the in-wheel The motor drive circuit is connected to the control system,
The steering device includes a steering motor that controls steering of a wheel, and a motor mounting seat, the motor mounting seat being connected to a lower wheel via a wheel leg bracket, and one outer end of the rocker arm having a motor mounting seat. The rocker arm is fixedly connected to the seat, and one inner end is connected to the chassis frame via a rotating couple that includes the rocker arm rotation axis, so that the rocker arm can be rotated transversely to the longitudinal axis of the vehicle body about the rocker arm rotation axis. The distance of the corresponding wheel from the longitudinal axis of the vehicle body can be changed,
The tread adjustment actuator includes a drive device, a first electromagnetic clutch, a second electromagnetic clutch, and two front and rear linear slide rail devices, and the two linear slide rail devices are connected to the chassis frame along the longitudinal axis of the vehicle body. The sliders are both driven by the drive device via a transmission mechanism, and the drive device transmits power to the slider of the front linear slide rail device via a first electromagnetic clutch, Power is transmitted to the slider of the rear linear slide rail device through an electromagnetic clutch, and the control signal input ends of the drive device and the two electromagnetic clutches are respectively connected to a control system, and the start/stop and on/off are controlled by the control system. ,
The left and right drive wheel legs at the front of the vehicle body are connected to the sliders of the front linear slide rail device through a pair of link structures, and the left and right drive wheel legs at the rear of the vehicle body are connected to the slider of the front linear slide rail device through a pair of link structures. The link structure is composed of a drive link and a rocker arm extension rod, one end of which is connected to a self-locking connector via a rotating pair, and the other end of the rocker arm extension rod is connected to a rocker arm extension rod. The drive link is fixedly connected to the arm and is used to drive and rotate the rocker arm, and the other end of the drive link is hinged to the corresponding slider through a rotating pair, and the linear movement of the slider is controlled by the rocker arm extension rod. Converts to rotational movement by driving and rotating around the rocker arm rotation axis,
The self-locking connector is composed of a first connecting block, a second connecting block, and a positioning pin electromagnet. A locking electromagnet is attached to one of the connecting blocks, and when the locking electromagnet is energized, the two connecting blocks are firmly attached by magnetic attraction. , the self-locking connector is in a coupled state, the first connecting block is fixedly attached to the end of the rocker arm extension rod, the second connecting block is connected to the drive link via a rotating pair, and the second connecting block is connected to the drive link via a rotating pair; A stopper hole is provided in the second connecting block, the positioning pin electromagnet is attached to the drive link, and when the locking electromagnet is de-energized, the first connecting block and the second connecting block lose their magnetic restraint, and the self-locking connector is closed. turned off, the control system controls the locating pin electromagnets to operate simultaneously and inserts the pin rod extending therefrom into the stopper hole of the second connecting block, so as to prevent free rotation of the second connecting block;
The wheeled agricultural robot is
The first electromagnetic clutch, the second electromagnetic clutch, and each self-lock connector are all in a connected state, and the drive device is in four-wheel tread synchronous adjustment mode A) in which the treads of the front and rear wheels are synchronously adjusted via two linear slide rail devices. ,
The first electromagnetic clutch and each self-locking connector are in the connected state, the second electromagnetic clutch is turned off, and the drive device adjusts the front wheel tread through the front linear slide rail device. Front wheel tread individual adjustment mode B) ,
The second electromagnetic clutch and each self-locking connector are in the connected state, the first electromagnetic clutch is turned off, and the drive device adjusts the rear wheel tread through the rear linear slide rail device. Rear wheel tread individual adjustment mode C) ,
The first electromagnetic clutch, the second electromagnetic clutch, and each self-lock connector are all in the off state, and the four-wheel position individual adjustment mode D allows the distances of the four wheels from the longitudinal axis of the vehicle body to be adjusted individually without interfering with each other. ) includes four types of tread adjustment modes,
A), B), and C) are active adjustment modes, in which the rocker arm is driven to swing laterally by controlling the drive device, and D) is a passive adjustment mode, in which the rotation of the in-wheel motor is controlled. By individually controlling the wheels, the corresponding wheels are driven to move forward or backward, thereby driving the rocker arms to swing in the lateral direction, thereby changing the distance of the wheels from the longitudinal axis of the vehicle body. A wheel-type agricultural robot.

Based on the above solutions, further improved solutions or preferred solutions further include the following.

Furthermore, the second connection block is a convex block, and a protrusion structure is provided on the surface that abuts against the first connection block, and the first connection block is a concave block, and the abutment surface conforms to the shape of the protrusion structure. A recessed groove structure is provided, a pressure sensor and a stroke switch are provided in the recessed groove structure, signal output ends of the pressure sensor and stroke switch are connected to a control system, and a first connection block and a second connection block are provided. When adsorbing, the protrusion structure is inserted into the groove structure and contacts the pressure sensor and the stroke switch, and if the signal fed back from the pressure sensor is above a preset threshold, the control system determines that the link structure is strong. , select an appropriate active adjustment mode from modes A) to C) and activate the corresponding slider.

Furthermore, the first connection block is provided with two insertion plates, and the two insertion plates are located on both left and right sides of the groove structure, protrude from the abutting surface of the first connection block, and correspond to the second connection block. A slot is provided to fit the position of the
When the first connection block and the second connection block are attracted by magnetic force, the insertion plate of the first connection block is locked in the slot of the second connection block, and the inner sides of the two insertion plates are chamfered toward the protrusion structure. A slope is provided.

Preferably, the driving device is a servo motor, and the linear slide rail device adopts a screw electric slide rail device, and the servo motor is installed in the center of the chassis frame and is located between the two screw electric slide rail devices. The two electromagnetic clutches are each attached to the power input ends of the two screw electric slide rail devices near the center of the chassis, and the output shaft of the servo motor is connected to the input shaft of the two electromagnetic clutches via a transmission mechanism. That is, power is transmitted to the two front and rear screw electric slide rail devices through two electromagnetic clutches.

Furthermore, a grid scale is provided on the side of the linear slide rail device, which is connected to a control system and used to measure the stroke of the slider on the rail, and the control system controls the stroke of the slider so as to accurately measure the tread. Achieve control.

Furthermore, the wheeled agricultural robot is provided with a navigation system, and the control system controls the operation of the tread adjustment actuator based on the signal fed back from the navigation system.
The navigation system includes a terrain detection sensor, a satellite positioning receiver, and an inertial sensor, and the control system receives terrain information detected by the terrain detection sensor, vehicle position information received by the satellite positioning receiver, and Based on the vehicle posture information fed back from the inertial sensor, the system analyzes the position and spacing of crop rows in front of the vehicle, calculates an appropriate tread adjustment amount, and outputs a corresponding control signal to the tread adjustment actuator.

A manual tread adjustment method based on the wheeled agricultural robot applied in passive adjustment mode D and performed with the vehicle body not running, the method comprising:
The operator plans the amount of wheel tread adjustment for each drive wheel leg in advance based on the terrain or the spacing of the rows of crops in front of the vehicle body, and based on the amount of tread adjustment, adjusts the amount to the control system of the robot via the remote control terminal. Step 1) of sending the command;
Upon receiving the adjustment command, the control system first controls each lock connector to turn off, then controls the drive device of the tread adjustment actuator to start, and pushes the slider of each linear slide rail device to initialize. Then, the first electromagnetic clutch and the second electromagnetic clutch are controlled to be turned off at the same time, and finally, control commands corresponding to the in-wheel motor and steering motor are outputted to drive the wheels. The rocker arm is moved forward or backward around the rotation axis to change the vertical distance between the wheel and the longitudinal axis of the vehicle body, and after the wheel is sufficiently adjusted, the in-wheel motor is controlled to stop. A manual tread adjustment method comprising the steps of: (2) controlling the electric brake at the arm rotation axis so that it immediately operates and fixing the rocker arm.

A tread automatic adjustment method based on a wheeled agricultural robot applied in the active adjustment mode A), B) or C), comprising:
A 3D laser radar is attached to the front of the vehicle body as a terrain detection sensor, and the agricultural robot uses the 3D laser radar to scan the ground and crops in front of it while moving, and uses the vehicle's geographical position data transmitted from the satellite positioning system. A 3D point cloud map of the field scene based on the vehicle body is constructed using the chassis frame posture data fed back from the inertial sensor and the 3D point cloud map of the field scene is converted to a point cloud map based on the earth coordinate system OZFZ. The vertically upward Z coordinate indicates the ground height of the three-dimensional point, the X direction indicates the vertical direction of the horizontal plane, that is, the robot's running direction, and the Y direction indicates the horizontal direction perpendicular to the X direction on the horizontal plane.Step 1) and,
An appropriate crop height threshold is set based on the type of crop and its growth stage, and points in the three-dimensional point cloud map of the field scene whose height coordinates are greater than the height threshold are determined to be points in the crop row cluster. step 2), thereby separating the crop row cluster point cloud from the three-dimensional point cloud map, followed by calculating the midpoint of each crop row cluster, and setting the vertical connection of the midpoints as the center line of the crop row. and,
After obtaining the center line of each row of crops, the distance between the rows of crops in front of the robot body is calculated in real time based on the current position of the robot vehicle body, and the position between the rows where the left and right wheels of the vehicle body are located or the number of rows to be straddled is referenced. , step 3) of calculating the theoretical width of the two sets of front and rear wheels, that is, the target width for tread adjustment;
Obtain the actual width of the tread, calculate the difference between the actual width of the tread and the target width of the tread adjustment, and the control system responds to the linear slide rail device based on the control policy of tread change according to the crop row. Output a control command to drive the rocker arm by moving the slider to rotate a fixed yaw angle to move the front and/or rear wheels from the longitudinal axis of the vehicle to fit between the rows of crops in front of the vehicle. An automatic tread adjustment method characterized by comprising step 4) of adjusting the distance.

Furthermore, in step 1), a Hessian plane equation is fitted using the RANSAC algorithm based on the three-dimensional point cloud map of the field scene, and the ground to be detected is segmented and reconstructed using least squares fitting.

The wheeled agricultural robot of the present invention can adjust the adaptability of the tread based on changes in crop row spacing and topography, significantly reducing the occurrence of seedling holding, and making it suitable for work by agricultural robots. The present invention has multiple adjustment modes, such as wheel tread synchronization adjustment, two-wheel individual adjustment and four-wheel individual adjustment, which can expand the terrain range, improve work efficiency, and reduce work cost. When encountering complex terrain such as objects, narrow roads, etc., it can ensure that the chassis passes smoothly, the structure plan is reasonable, easy to operate and maintain, and is suitable for popularization and use.

1 is a schematic diagram of the overall structure of a specific embodiment of the agricultural robot of the present invention. FIG. 2 is a structural schematic diagram of a drive wheel leg of the agricultural robot in FIG. 1; FIG. 2 is a schematic diagram of crop rows. FIG. 2 is a structural schematic diagram of a tread adjustment actuator. FIG. 2 is a topology structure diagram in which the agricultural robot of the embodiment shown in FIG. 1 realizes automatic tread adjustment; FIG. 3 is a control principle diagram of tread adaptive adjustment. It is a structural schematic diagram of a link structure. FIG. 1 is a schematic structural diagram of a self-locking connector. FIG. 2 is a schematic diagram 2 of a structure of a self-locking connector. It is a structural schematic diagram of a convex block. It is a structural schematic diagram of a concave block. FIG. 3 is a schematic diagram of the installation of a pressure sensor and a stroke switch. It is a top view of a convex block. FIG. 1 is a schematic structural diagram of a tread adjustment actuator and a driving wheel leg. FIG. 2 is a schematic diagram 2 of the structure of a tread adjustment actuator and a driving wheel leg. FIG. 2 is a partial structural schematic diagram of a tread adjustment actuator and a drive wheel leg. FIG. 3 is a structural schematic diagram of a tread adjustment actuator, a chassis frame, and a driving wheel leg. It is a control principle diagram of a chassis tread.

In order to explain the technical solution of the present invention in detail, the present invention will be further explained below with reference to drawings and specific embodiments.

The wheeled agricultural robot with tread adaptive adjustment function as shown in FIG. 1 includes a vehicle body 3, a control system, a navigation system, a tread adjustment actuator, and a dosing system. The vehicle body 3 is provided with four driving wheel legs on the front, rear, left and right sides, and the wheels 10 of each driving wheel leg are driven by individual in-wheel motors 14, so that a four-wheel differential can be realized, and Each wheel 10 has an individual steering device 8. The navigation system, tread adjustment actuator, dosing system, in-wheel motor 10 and steering device 8 are each connected to a control system, and are controlled to start and stop by the control system.

The dosing system comprises a medicine box 4, a spray rod 1 and an infusion pipeline, the medicine box 4 is attached to the car body 3, and the spray 1 rod is hung on the tail of the car body 3 by the cell balance spray rod suspension 2.

The navigation system includes components such as a terrain detection sensor 6, a satellite positioning receiver 4, an inertial sensor, and a wheel odometer. The terrain detection sensor 6 is attached to the front part of the vehicle body and is used to detect terrain information including the ground and crops, preferably employs a three-dimensional laser radar (three-dimensional scanning laser sensor), and is connected to the satellite positioning receiver. 4 is connected to a satellite positioning system and is used to provide real-time driving position information of the vehicle body 3, and an inertial sensor is attached to the vehicle body to provide information on the vehicle body or vehicle chassis frame, including data such as pitch angle and roll angle. The wheel odometer may be a rotary encoder, and is used to measure the rotation angle and rotation speed of the wheel, and can further calculate the distance traveled by each wheel. The robot needs to travel in the field to detect the field scene and generate a direction reference trajectory.Then, the target rotation speed of the in-wheel motors of the four wheels is calculated from the direction reference trajectory, and the control system The rotational speed of the in-wheel motor of two wheels is controlled in real time to track the target rotational speed, and the wheel odometer measures the wheel rotational speed as the feedback input of the control system, thus realizing real-time closed-loop control. I do.

The control system analyzes the position and spacing of the crop rows in front of the vehicle body 3 based on the data fed back from the navigation system, calculates an appropriate tread adjustment amount, and outputs a corresponding control signal to the tread adjustment actuator. .

The four driving wheel legs of the vehicle body 3 are connected to the chassis frame via rocker arms 7, respectively. Each drive wheel leg includes a wheel 10 and a steering device 8 that individually controls the wheel 10. The steering device 8 is composed of a steering motor and a motor mounting seat. The motor mounting seat is provided above the wheel leg bracket 9, and the upper part of the wheel leg bracket 9 is connected to the motor mounting seat via an upright bracket rotating shaft, and by starting the steering motor, the wheel leg bracket 9 and wheels 10 are driven to perform steering. One outer end of the rocker arm 7 is fixedly connected to the motor mounting seat, and one inner end is connected to the chassis frame through a first rotating pair. The rotation axis of the first rotation pair is a rocker arm rotation axis 12, which is vertically attached to the chassis frame and fixedly connected to the rocker arm 12. When the rocker arm 7 rotates about the rocker arm rotating shaft 12, it drives the driving wheel leg to swing laterally, thereby changing the distance of the wheel 10 from the longitudinal axis of the vehicle body. Further, an angle sensor 11 for detecting the rotation angle of the rocker arm rotation shaft 12 is attached to the rocker arm rotation shaft 12 or the chassis frame, and the angle sensor 11 is connected to a control system to feed back the yaw angle of the rocker arm. A rotary encoder is preferably used.

The tread adjustment actuator includes a first electromagnetic clutch 17-1, a second electromagnetic clutch 17-2, a drive device 18, a gear reduction box, and two linear slide rail devices, front and rear.

A two-stage linear slide rail is laid and installed on the chassis frame along the longitudinal axis of the device vehicle body, and in this embodiment, the driving device 18 adopts a servo motor, and the linear slide rail device is a screw electric slide rail device. Adopt.

The screw electric slide rail device is composed of components such as a screw 15-1, a guide rail 15-2, and a slider 15-3. The two guide rails 15-2 are provided on the left and right sides of the screw 15-1 and are parallel to the screw, and the slider 15-3 is attached to the two guide rails 15-2 and connected to the screw nut. When the screw is rotationally driven by the servo motor, the screw nut drives the slider 15-3 to linearly reciprocate along the guide rail.

A control signal input terminal of the servo motor is connected to a control system, and starting and stopping of the servo motor are controlled by the control system. As shown in FIG. 4, the servo motor is mounted in the center of the chassis frame and located between the two screw electric slide rail devices. The two electromagnetic clutches 17-1 and 17-2 are respectively attached to the power input ends of the two screw electric slide rail devices near the center position of the chassis. The gear reduction box is provided with one power input end (driving conical gear) and two power output ends (driven conical gear), and the output shaft of the servo motor is connected to the power input end of the gear reduction box. The two power output ends of the two electromagnetic clutches are respectively connected to the power input ends of the two electromagnetic clutches, and the power output ends of the two electromagnetic clutches are connected to the corresponding screw shafts. Considering that the output shaft of the servo motor is perpendicular to the lead screw direction, the gear reduction box adopts a bevel gear to transmit power. The two electromagnetic clutches have their control signal input ends connected to the control system, and are controlled to be turned on and off by the control system, that is, when the first/second electromagnetic clutch is turned off, the power of the servo motor is transferred to the rear/front screw When both electromagnetic clutches are turned on, four-wheel synchronous adjustment is performed.

On either side of the front and rear screw electric slide rail devices there are provided grating scales connected to the control system and for measuring the stroke in the rail of each slider, indicating the current tread of the vehicle body chassis.

The left and right driving wheel legs at the front of the vehicle body 3 are each connected to the slider of the front screw electric slide rail device via a pair of link structures, and the left and right driving wheel legs at the rear of the vehicle body are each connected to a pair of links. The rear screw is connected to the slider of the electric slide rail device through the structure. As shown in FIGS. 4, 14 and 17, the link structure is composed of a rocker arm extension rod 13-1 and a drive link 13-2, one end of which is connected to a self-locking connector through a second rotating pair. The other end of the rocker arm extension rod 13-1 is fixedly connected to the rocker arm 7 and is used to drive the rocker arm 7 to rotate around the rocker arm rotation axis 12, and the other end of the rocker arm extension rod 13-1 is connected to the rocker arm extension rod 13-1. The other end of 2 is hinged to the corresponding slider via a third rotating pair, and converts the linear movement of the slider into rotational movement that drives the rocker arm extension rod 13-1 to rotate about the rocker arm rotation axis 12. Convert.

As shown in FIGS. 7 to 13, the self-locking connector includes components such as a first connecting block 13-3, a second connecting block 13-5, and a locating pin electromagnet 13-4. A lock electromagnet 13-5-3 is attached to the second connection block 13-5, and when the lock electromagnet 13-5-3 is energized, the two connection blocks are connected by magnetic attraction. The first connecting block 13-3 is fixedly attached to the end of the rocker arm extension rod 13-2, and the second connecting block 13-5 is hinged to the drive link 13-1 via the second rotating pair. An oblong stopper hole 13-5-2 is provided in the second connection block 13-5, and the positioning pin electromagnet 13-4 is attached to the end of the drive link 13-1. Once the pin holes are evenly distributed at the end of 1, and the locking electromagnet 13-5-3 is de-energized, the control system controls the positioning pin electromagnet 13-4 to operate, and then The extending pin rod passes through the pin hole of the drive link 13-1 and is inserted into the stopper hole 13-5-2 of the second connecting block 13-5, thereby allowing the second connecting block 13-5 to rotate freely. It can be prevented.

When the locking electromagnet 13-5-3 is de-energized, the self-locking connector is turned off, and the connection between the drive link 13-1 and the rocker arm extension rod 13-2 is cut, and thus the four-wheel vehicle body This allows for individual adjustment of the tread from the vertical axis.

The second connecting block 13-5 is a convex block, and as shown in FIG. 10, a protruding structure is provided on the surface that abuts against the first connecting block, and the protruding structure has an upper semi-cylindrical body and a lower semi-cylindrical body. The rotating shaft 13-5-1 of the second rotating pair, which is composed of a conical body, is attached to the second connecting block 13-5. The first connection block 13-3 is a concave block, and a concave groove structure matching the shape of the protrusion structure is provided on the abutting surface of the first connection block 13-3.As shown in FIG. Further, two insertion plates 13-3-2 are provided, and the two insertion plates 13-3-2 are located on both left and right sides of the groove structure, protrude from the abutting surface of the first connection block 13-3, Two slots are provided which fit into corresponding positions of the connection block 13-5. When the first connection block 13-3 and the second connection block 13-5 are attracted by magnetic force, the protrusion structure is fitted into the groove structure, and the insertion plate 13-3-2 is inserted into the slot. Due to the uneven structure, the insertion plate, and the slot structure, the two connecting blocks are unlikely to shift in the direction perpendicular to the magnetic force even when they are in an attracted state. Chamfers are provided on the inner corners of the two insertion plates 13-3-2, and the chamfered slopes 13-3-3 face the protrusion structure, thereby quickly and accurately positioning the two connecting blocks when butting against each other. be able to.

Further, a pressure sensor 19 and a stroke switch 20 are provided within the groove structure, and the stroke switch 20 is used to determine whether the first connection block and the second connection block are connected to predetermined positions. , the pressure sensor 19 is used to determine the strength of the connection between the two. The signal output ends of the pressure sensor 19 and the stroke switch 20 are connected to a control system, and when the first connection block and the second connection block are attracted, the protrusion structure is fitted into the groove structure, and the pressure sensor 19 and stroke Switch 20 can be contacted. The control system controls the electromagnetic clutch to engage after receiving the signals transmitted from the stroke switch 20 and the pressure sensor 19, and when the data fed back from the pressure sensor 19 exceeds a preset threshold, the control system controls the electromagnetic clutch to engage. The system ensures that the link structure is securely fixed and enables the servo motor to drive the slider.

The wheeled agricultural robot of this example is
The first electromagnetic clutch, the second electromagnetic clutch, and each self-lock connector are all in a connected state, and the drive device (18) performs four-wheel tread synchronization adjustment to synchronize the treads of the front and rear wheels via two linear slide rail devices. Mode A),
The first electromagnetic clutch, each self-locking connector is in the coupled state, the second electromagnetic clutch is turned off, and the drive device (18) adjusts the front wheel tread individual adjustment through the front linear slide rail device. Mode B),
The second electromagnetic clutch, each self-locking connector is in the coupled state, the first electromagnetic clutch is turned off, and the drive device (18) adjusts the tread of the front wheel through the rear linear slide rail device rear wheel tread individual Adjustment mode C),
The first electromagnetic clutch, the second electromagnetic clutch, and each self-lock connector are all in the OFF state, and there are four wheel position individual adjustment modes D) in which the distances of the four wheels from the longitudinal axis of the vehicle body are individually adjusted. Includes tread adjustment mode,
A), B), and C) are active adjustment modes, and D) is a passive adjustment mode, and the four modes A), B), C), and D) may be closed-loop automatic control. , and may be open-loop manual control.

Preferably, the agricultural robot of this embodiment may activate an automatically controlled active adjustment mode while running, and the tread automatic adjustment method specifically includes the following steps.

1) While the robot is running in the field, it uses a three-dimensional laser radar to scan the ground and crops in front of it, and collects vehicle body geographical position data transmitted from a satellite positioning system and chassis frame posture data fed back from an inertial sensor. is used to construct a three-dimensional point cloud map of a field scene based on the earth coordinate system OZFZ, a Hessian plane equation is fitted using the RANSAC algorithm, and the ground to be detected is subdivided and reconstructed using least squares fitting.

In the earth coordinate system, the vertically upward Z coordinate indicates the height above the ground of a three-dimensional point, the X direction indicates the vertical direction of the horizontal plane, that is, the robot's running direction, and the Y direction indicates the horizontal direction of the horizontal plane, which is perpendicular to the X direction. It is.

2) Based on the type of crop and its growth stage, the control system sets an appropriate crop height threshold, and detects points whose height coordinates (Z coordinates) are larger than the height threshold in the three-dimensional point cloud map of the field scene. The crop row cluster point cloud is determined to be a point in a crop row cluster, thereby separating the crop row cluster point cloud from the three-dimensional point cloud map, the midpoint of each crop row cluster is calculated, and the vertical connection line of the midpoint is connected to the crop row cluster. Center line.

3) After obtaining the center line of each crop row, calculate the distance between the rows of crops in front of the robot body in real time based on the current traveling position of the robot vehicle body, and calculate the position between the rows where the left and right wheels of the vehicle body are located or the row to be straddled. The theoretical width of the two sets of front and rear wheels, that is, the target width for tread adjustment is calculated by referring to the numbers.

4) Obtain the actual width of the tread, calculate the difference between the actual width of the tread and the target width of the tread adjustment, and use the control policy (optimal control method or proportional-integral-derivative method) for tread change according to the crop row. Based on the control method (PID), a control command corresponding to the linear slide rail device is output, and the rocker arm is driven by the movement of the slider to rotate by a certain yaw angle to fit between the rows of crops in front of the vehicle body. Adjust the distance of the wheel from the longitudinal axis of the vehicle body. After the yaw angle of the rocker arm is sufficiently adjusted, the electric brake 21 at the rocker arm rotation axis is controlled to operate, the rocker arm rotation axis is prevented from rotating with respect to the chassis frame, and the tread is fixed.

Before implementing the tread automatic adjustment method, it is necessary to set a tread adjustment threshold, and during the adjustment process, when the target tread width that requires adjustment exceeds the threshold, the robot will move in consideration of safety. , and tread adjustment is done after stopping forward movement. Thereby, the connection stress between the rocker arm and the robot vehicle body can be reduced as much as possible.

Regarding the passive adjustment mode D), the agricultural robot of this embodiment preferably adopts an open-loop tread manual adjustment method, and specifically includes the following steps.
1) The operator plans in advance the amount of tread adjustment of the drive wheel leg to be adjusted based on the terrain in front of the vehicle body or the distance between rows of crops, and controls the robot via a remote control terminal based on the amount of tread adjustment. send adjustment instructions to the system,
The remote control terminal is provided with a user interface for an operator to select an adjustment mode and input a tread adjustment amount command;
2) After transmitting the adjustment command, the control system first controls the drive wheel leg to be adjusted to stop energizing the lock electromagnet of the corresponding lock connector, and then connects the first connection block 13- 3 and the second connecting block 13-5 lose their restraint due to the magnetic attraction force, disconnecting the drive link 13-1 and rocker arm extension rod 13-2, and stopping power supply to the lock electromagnet 13-5-3. At the same time, the positioning pin electromagnet 13-4 is controlled to operate, the pin rod extending from it is inserted into the stopper hole of the second connection block, the degree of freedom of the second connection block is restricted, and the slider is applied. Avoiding that the two connecting blocks cannot be timely and accurately matched when adjusting the tread,
Subsequently, the control system controls the servo motor to rotate, move the slider of each lead screw electric slide rail device to its initial position, return its drive link to a state parallel to the lead screw, and rotate the drive link and other Avoid contact with other parts.
Next, the control system controls the first electromagnetic clutch and the second electromagnetic clutch to be turned off simultaneously and not to participate in tread adjustment;
Finally, the control system outputs a control command corresponding to the in-wheel motor 14 and the steering motor 8, drives the wheel 10 to move around the rocker arm rotation axis 12, and moves the wheel 10 forward or backward to lock the rocker. driving the yaw rotation of the arm, the operator can observe the angle through which the rocker arm has rotated by a meter on the control terminal or the vertical distance from the longitudinal axis of the vehicle body of the wheel center collected by other sensor devices; The user interface displays the changes in the distance parameters of the four wheels in real time, and when the yaw angle of the rocker arm is adjusted sufficiently, the in-wheel motor 14 stops, the electric brake immediately locks the movement of the rocker arm, The rotation axis of the rocker arm is fixed at a certain angle, thus realizing individual adjustment to the tread of the wheel 10 (after the vehicle body is started, the steering motor 8 is used to adjust the rotation direction based on the next direction of travel). (controls the wheels to perform a super turning).

Passive adjustment mode D) is applicable to complex road conditions and allows the robot to smoothly pass through water ditches, obstacles, or long narrow paths in the field. While running the passive adjustment mode, the user can operate the control system before controlling the wheel rotation, and the individual adjustment of the four driving wheel legs is combined with the on-off control of the corresponding electromagnetic clutch and locking electromagnet. Although this can be realized by using a servo motor and a screw electric slide rail device, it is preferable to operate by adopting the above-mentioned manual tread adjustment method and to operate while the vehicle body is stopped.

In each adjustment mode, the control principle of the chassis tread is as follows.

As shown in Fig. 18, absolute value encoders are attached to the four rocker arm rotation axes for tread adjustment to measure the rocker arm rotation angles α1, α2, α3, and α4 with respect to the longitudinal axis of the vehicle body. There is. As shown in the figure, the center distance of the left and right rocker arm rotation axes is W1, the center distance of the front and rear rocker arm rotation axes is L1, and the length of the tread adjustment rocker arm is D (from the upper rotation axis of the wheel leg bracket of the rocker arm main axis). The corresponding front wheel tread W2 and rear wheel tread W3 can be obtained from the angle measured by the rotary encoder in real time, and the calculation formula is:
W2=W1+D・sin(α1)+D・sin(α2)
W3=W1+D·sin(α3)+D·sin(α4).
The calculation formula for the corresponding front wheel tread 12 and front wheel tread 13 is:
L2=L1+D・cos(α1)+D・cos(α2)
L3=L1+D.cos(α3)+D.cos(α4).

In the four-wheel synchronous control mode, the rotation angles of the rocker arms with respect to the longitudinal axis of the vehicle body are equal, ie, α1=α2=α3=α4, W2=W3.

In the front wheel tread individual adjustment mode or the rear wheel tread individual adjustment mode, the rotation angles of the two front wheel rocker arms with respect to the longitudinal axis of the vehicle body are equal, and the rotation angles of the two rear wheel rocker arms with respect to the longitudinal axis of the vehicle body are equal, that is, α1= α2, α3=α4.

In a special case, in the four-wheel position individual adjustment mode, the rotation angles of the rocker arms with respect to the longitudinal axis of the vehicle body are unequal.

Taking the active adjustment mode as an example, the agricultural robot measures point cloud data of crops, ground, etc. in front of the vehicle using a 3D laser radar, converts the point cloud to the earth coordinate system using an inertial attitude sensor and a satellite positioning system, and then Performing adaptive tread adjustment based on the traveling position coordinates of the chassis, the control system extracts the inter-row Wd of the two crop rows closest to the left and right wheels of the chassis based on the point cloud data, and further calculates the distance between W2 and Wd. The difference, the difference between W3 and Wd, is input to the control system. The output of the control system is a rotation speed control command for the servo motor and commands to open and close the two electromagnetic clutches. When the tread is sufficiently adjusted, the electric brake 21 at the rocker arm rotation axis is locked.

The agricultural robot control system of the present invention includes a plurality of dedicated control units including a motor controller, a navigation control unit, a work machine control unit, etc., and the motor controller is connected via a CAN bus, and has different sensors and functions. Both control units are connected via Ethernet and communicate using TCP/IP.

The foregoing has illustratively explained the basic principles, main features and advantages of the invention. As will be understood by those skilled in the art, the present invention is not limited to the above embodiments, and the embodiments and specification described above are merely for illustrating the principles of the present invention. The invention may further be modified and modified without departing from its spirit and scope, and the patentable scope of the invention is defined by the appended claims, the specification and their equivalents.

Claims (9)

A wheeled agricultural robot having a tread adaptive adjustment function, comprising a control system and a vehicle body (3) provided with four driving wheel legs,
A tread adjustment actuator is further provided;
The four driving wheel legs of the vehicle body (3) are each connected to the chassis frame via a corresponding rocker arm (7), and the driving wheel legs each include a wheel (10) and a steering device (8). ) are all driven by individual in-wheel motors (14), the drive circuits of the in-wheel motors (14) are connected to the control system,
The steering device (8) includes a steering motor that controls the steering of the wheels (10) and a motor mounting seat, and the motor mounting seat is connected to the lower wheel (10) via a wheel leg bracket (9). One end of the outer side of the rocker arm (7) is fixedly connected to the motor mounting seat, and one end of the inner side is connected to the chassis frame via a rotating couple including the rocker arm rotation shaft (12). 7) is capable of swinging horizontally with respect to the longitudinal axis of the vehicle body around the rocker arm rotation axis (12), and is capable of changing the distance of the corresponding wheel from the longitudinal axis of the vehicle body;
The tread adjustment actuator includes a drive device (18), a first electromagnetic clutch (17-1), a second electromagnetic clutch (17-2), and two front and rear linear slide rail devices. The slide rail device is laid and attached to the chassis frame along the longitudinal axis of the vehicle body, and its sliders are both driven by the drive device (18) through a transmission mechanism, and the drive device (18) is connected to a first electromagnetic Power is transmitted to the slider of the front linear slide rail device via the clutch (17-1), power is transmitted to the slider of the rear linear slide rail device via the second electromagnetic clutch (17-2), (18) and the two electromagnetic clutches have their control signal input ends connected to the control system, and are controlled to start/stop and turn on/off by the control system;
The left and right drive wheel legs at the front of the vehicle body are connected to the sliders of the front linear slide rail device through a pair of link structures, and the left and right drive wheel legs at the rear of the vehicle body are connected to the slider of the front linear slide rail device through a pair of link structures. The link structure is composed of a drive link (13-1) and a rocker arm extension rod (13-2), one end of which is connected to a self-locking connector via a rotating pair, and The other end of the rocker arm extension rod (13-1) is fixedly connected to the rocker arm (7) and is used to drive and rotate the rocker arm (7). The end is hinged to the corresponding slider via a rotating pair, converting the linear movement of the slider into a rotational movement that drives the rocker arm extension rod (13-2) to rotate about the rocker arm rotation axis (12). death,
The self-locking connector is composed of a first connection block (13-3), a second connection block (13-5), and a positioning pin electromagnet (13-4), and one of the connection blocks has a locking electromagnet (13-5). -3) is attached and the locking electromagnet (13-5-3) is energized, the two connecting blocks are firmly connected by magnetic attraction, the self-locking connectors are in a coupled state, and the first connecting block (13-5-3) is connected firmly. 3) is fixedly attached to the end of the rocker arm extension rod (13-2), and the second connecting block (13-5) is connected to the drive link (13-1) via a rotating pair, and A stopper hole (13-5-2) is provided in the 2 connection block (13-5), a positioning pin electromagnet (13-4) is attached to the drive link (13-1), and a lock electromagnet (13-5-3) is attached to the drive link (13-1). ), the first connecting block and the second connecting block lose their magnetic restraint, the self-locking connector is turned off, and the control system controls the positioning pin electromagnet (13-4) to operate simultaneously. and inserting the pin rod extending therefrom into the stopper hole (13-5-2) of the second connection block (13-5) so as to prevent the second connection block (13-5) from freely rotating;
The wheeled agricultural robot is
The first electromagnetic clutch, the second electromagnetic clutch, and each self-lock connector are all in a connected state, and the drive device (18) performs four-wheel tread synchronization adjustment to synchronize the treads of the front and rear wheels via two linear slide rail devices. Mode A),
The first electromagnetic clutch, each self-locking connector is in the coupled state, the second electromagnetic clutch is turned off, and the drive device (18) adjusts the front wheel tread individual adjustment through the front linear slide rail device. Mode B),
The second electromagnetic clutch, each self-locking connector is in the coupled state, the first electromagnetic clutch is turned off, and the drive device (18) adjusts the rear wheel tread individual adjustment through the rear linear slide rail device. Mode C),
The first electromagnetic clutch, the second electromagnetic clutch, and each self-lock connector are all in the OFF state, and the distances of the four wheels from the longitudinal axis of the vehicle body can be adjusted individually without interfering with each other. Four-wheel position individual adjustment mode D) Including four types of tread adjustment modes,
A), B), and C) are active adjustment modes, in which the rocker arm (7) is driven to swing laterally by controlling the drive device (18), and D) is a passive adjustment mode, By individually controlling the rotation of the in-wheel motors, the corresponding wheels are driven to move forward or backward, thereby driving the rocker arms (7) to swing laterally, and aligning the longitudinal axis of the vehicle body with the wheels. A wheel-type agricultural robot characterized by changing the distance from the ground. The second connection block (13-5) is a convex block, and a protrusion structure is provided on the surface that abuts against the first connection block (13-3), and the first connection block (13-3) is a concave block. A concave groove structure that matches the shape of the protrusion structure is provided on the abutting surface, and a pressure sensor (19) and a stroke switch (20) are provided within the concave groove structure, and a pressure sensor (19) and a stroke switch (20) are provided in the concave groove structure. The signal output end of the switch (20) is connected to the control system, and when the first connection block and the second connection block are attracted, the protrusion structure is inserted into the groove structure, and the pressure sensor (19) and the stroke switch (20 ) and the feedback signal from the pressure sensor is above a preset threshold, the control system assumes that the link structure is firmly fixed and selects the appropriate active adjustment mode from modes A) to C). The wheeled agricultural robot with tread adaptive adjustment function according to claim 1, characterized in that it selects and activates the corresponding slider. Two insertion plates (13-3-2) are provided on the first connection block (13-3), and the two insertion plates (13-3-2) are located on both left and right sides of the groove structure. , a slot protruding from the abutting surface of the first connection block (13-3) and fitting into a corresponding position of the second connection block (13-5);
When the first connection block (13-3) and the second connection block (13-5) are attracted by magnetic force, the insertion plate (13-3-2) of the first connection block (13-3) is attached to the second connection block (13-5), and a chamfered slope (13-3-2) facing the protrusion structure is provided on the inside of the two insertion plates (13-3-2). A wheeled agricultural robot having a tread adaptive adjustment function according to claim 2. The driving device (18) is a servo motor, the linear slide rail device adopts a screw electric slide rail device, the servo motor is installed in the center of the chassis frame, and is located between the two screw electric slide rail devices. The two electromagnetic clutches are each attached to the power input ends of the two screw electric slide rail devices near the center of the chassis, and the output shaft of the servo motor is connected to the input shaft of the two electromagnetic clutches via a transmission mechanism. 2. The wheeled agricultural robot having a tread adaptive adjustment function according to claim 1, wherein power is transmitted to the two front and rear screw electric slide rail devices through two electromagnetic clutches. A grating scale (16) is provided on the side of the linear slide rail device and is connected to a control system for measuring the stroke of the slider on the rail, and the control system can control the stroke of the slider to ensure accuracy with respect to the tread. The wheeled agricultural robot having a tread adaptive adjustment function according to claim 1, wherein the wheeled agricultural robot has a tread adaptive adjustment function. A navigation system is provided, a control system controlling operation of the tread adjustment actuator based on signals fed back from the navigation system;
The navigation system includes a terrain detection sensor (6), a satellite positioning receiver (5), and an inertial sensor, and the control system includes terrain information detected by the terrain detection sensor and information received by the satellite positioning receiver. Based on the vehicle body position information fed back from the inertial sensor and the vehicle body posture information fed back from the inertial sensor, the position and spacing of the crop rows in front of the vehicle body are analyzed, the tread adjustment amount is calculated accordingly, and the corresponding control signal is sent to the tread adjustment actuator. The wheeled agricultural robot having a tread adaptive adjustment function according to any one of claims 1 to 5, which outputs the following: A manual tread adjustment method based on the wheeled agricultural robot according to any one of claims 1 to 6, which is applied in passive adjustment mode D and performed with the vehicle body not running,
The operator plans the amount of wheel tread adjustment for each drive wheel leg in advance based on the terrain or the spacing of the rows of crops in front of the vehicle body, and based on the amount of tread adjustment, adjusts the amount to the control system of the robot via the remote control terminal. Step 1) of sending the command;
Upon receiving the adjustment command, the control system first controls each lock connector to turn off, then controls the drive device of the tread adjustment actuator to start, and pushes the slider of each linear slide rail device to initialize. Then, the first electromagnetic clutch and the second electromagnetic clutch are controlled to be turned off at the same time, and finally, control commands corresponding to the in-wheel motor (14) and steering motor are output, and the wheels ( 10) to move forward or backward around the rocker arm rotation axis (12) to change the vertical distance between the wheel and the longitudinal axis of the vehicle body, and after the wheel is adjusted to a predetermined position, the in-wheel A tread comprising the steps of: (2) controlling the motor (14) to stop, controlling the electric brake (21) at the rocker arm rotation axis to immediately operate, and fixing the rocker arm. Manual adjustment method. The automatic tread adjustment method based on a wheeled agricultural robot according to claim 6, applied in the active adjustment mode A), B) or C),
A 3D laser radar is attached to the front of the vehicle body as a terrain detection sensor, and the agricultural robot uses the 3D laser radar to scan the ground and crops in front of it while moving, and uses the vehicle's geographical position data transmitted from the satellite positioning system. A 3D point cloud map of the field scene based on the vehicle body is constructed using the chassis frame posture data fed back from the inertial sensor and the 3D point cloud map of the field scene is converted to a point cloud map based on the earth coordinate system OZFZ. The vertically upward Z coordinate indicates the ground height of the three-dimensional point, the X direction indicates the vertical direction of the horizontal plane, that is, the robot's running direction, and the Y direction indicates the horizontal direction perpendicular to the X direction on the horizontal plane.Step 1) and,
An appropriate crop height threshold is set based on the type of crop and its growth stage, and points in the three-dimensional point cloud map of the field scene whose height coordinates are greater than the height threshold are determined to be points in the crop row cluster. step 2), thereby separating the crop row cluster point cloud from the three-dimensional point cloud map, followed by calculating the midpoint of each crop row cluster, and setting the vertical connection of the midpoints as the center line of the crop row. and,
After obtaining the center line of each row of crops, the distance between the rows of crops in front of the robot body is calculated in real time based on the current position of the robot vehicle body, and the position between the rows where the left and right wheels of the vehicle body are located or the number of rows to be straddled is referenced. , step 3) of calculating the theoretical width of the two sets of front and rear wheels, that is, the target width for tread adjustment;
Obtain the actual width of the tread, calculate the difference between the actual width of the tread and the target width of the tread adjustment, and the control system responds to the linear slide rail device based on the control policy of tread change according to the crop row. Output a control command to drive the rocker arm by moving the slider to rotate a fixed yaw angle to move the front and/or rear wheels from the longitudinal axis of the vehicle to fit between the rows of crops in front of the vehicle. An automatic tread adjustment method characterized by comprising step 4) of adjusting the distance. In step 1), a Hessian plane equation is fitted using a RANSAC algorithm based on the three-dimensional point cloud map of the field scene, and the ground to be detected is segmented and reconstructed by least squares fitting. 8. The automatic tread adjustment method described in 8.

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