JP2018042545A - Vegetable automatic harvester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vegetable automatic harvester moving a root cutting blade so as to match a target route in the soil and thereby capable of moving a root cutting blade smoothly in the soil and performing root cutting while suppressing variation.SOLUTION: A vegetable automatic harvester includes: a tilt frame driven to tilt in a travel direction of a machine body in a front part of a harvester body in the travel direction; and a lifting/lowering frame supported by the tilt frame so as to be lifted/lowered and including a root cutting blade attached in a lower edge. A blade tip of the root cutting blade moves periodically with a route 1 for moving from an upper position toward a lower position in an arc shape and a route 2 for moving from a terminal point of the route 1 to a start point of the next route 1 vertically upward as a route for one period by an angle control mechanism controlling a tilt angle of the tilt frame and a height control mechanism controlling a lifting/lowering position of the lifting/lowering frame.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an automatic vegetable harvesting machine.

At present, harvesting of soft vegetables such as spinach is mainly done manually, and mechanization of the harvesting work is expected. On the other hand, some automatic harvesting devices have been developed, but have not been widely used (Non-Patent Documents 1-3 and Patent Document 1). One of the causes is that the conventional harvesting method involves gripping the harvest. Soft vegetables are very fragile, and the leaves are damaged by gripping and the commercial value is impaired. Currently, no harvesting device exists to solve this problem. Therefore, our group is developing spinach harvesting equipment that does not involve gripping using a mechanism that can control the position and posture of the root cutting blade for cutting roots (Patent Document 2, Non-Patent Documents 4-7). ).
In this harvesting device, a root cutting blade is advanced from the ground surface into the soil at a certain depth to perform root cutting. And with the conveyor attached to the back of the root cutting blade, the lower part of the center of gravity of the object immediately after the root cutting is pushed, and collection is performed by tilting to the conveyor side. This allows harvesting without gripping.

Japanese Patent Laid-Open No. 11-308912 JP 2014-166175 A

Yoshiichi Tomokazu, et al., Development of spinach harvesting technology (1st report), Agricultural Machinery Journal, 62, 3 (2000) 149 Yuki Kobayashi, et al., Development of a simple spinach harvester (1st report), Journal of the Agricultural Machinery Society, Vol. 60, No. 2 (1998), pp. 103-110 Junichi Nishizawa, Development and dissemination of dedicated harvesters for processing soft vegetables such as spinach, Agriculture, Forestry and Fisheries Research Journal, Vol. 35, No. 11 (2012), pp. 37-41 Maruyama Hirotomo, et al., Development of Automatic Harvester for Raw Food, 12th System Integration Division Lecture, pp, 2100-2103 (2011) Kosuke Hirano, et al., Development of Automatic Spinach Harvester for Raw Food-Design and Verification of Recovery / Transport Equipment-, Robomec Mechatronics Lecture 2012, Paper NO.1A1-G04 (CD-ROM) Marutama Hirotomo, et al., Consideration and Position Control of Root Cutting Blade Operation in Spinach Automatic Harvester, 13th SICE System Integration Division Conference, (2012) Kosuke Hirano, et al., Design and control of two-degree-of-freedom control mechanism of root cutting blade in soft vegetable automatic harvesting machine, The 56th Automatic Control Joint Lecture, (2013) Yuichi Senda, Development of an automatic spinach harvester based on passive handling, Journal of Japan Society for Precision Engineering, Vol.81, No.9 (2015) Akihiro Fujisawa, et al., Analysis of soil behavior by root-cutting blade motion in a spinach automatic harvesting machine, Journal of the Japan Society of Mechanical Engineers, Vol.81, No.832 (2015) Takamitsu Hatakeyama, et al., Position control of root cutting blade in soil in weak vegetable automatic harvesting device, SICE2016 Akihiro Fujisawa, et.al., Motion Analysis of the Root-Cutting Blade for an Automatic Spinach Harvester, MOVIC2014, (2014) Masamitsu Kurisu, et al., Trajectory planning and dynamic control of mobile manipulators, Transactions of the Japan Society of Mechanical Engineers, (1996), pp.242-248 Ohtsuhisa, Control of mobile manipulator, Journal of the Robotics Society of Japan, Vol.13 (1995), pp.904-907 Akihiro Fujisawa, et.al., Optimzed trajectory planning a root-cutting blade for an automatic spinach harvester, Dynamics and Desing Conference 2015. (2015)

In the spinach harvesting apparatus described above, control target values obtained by trial and error for each mechanism are used to perform harvesting operations. Therefore, the path along which the blade moves is not strictly specified, and the path cannot be verified sufficiently.
On the other hand, by specifying a desired route and applying the control target value of each mechanism based on the route to the actual machine, the route parameter can be specifically evaluated. Accordingly, an object of the present application is to provide an automatic vegetable harvesting machine that sets a path that is advantageous for harvesting, compares it with the current path, and performs an accurate harvesting operation.

The vegetable automatic harvesting machine according to the present invention is supported at the front part in the traveling direction of the harvesting machine body by a tilting frame that is tilted and driven in the traveling direction of the machine body, and can be moved up and down by the tilting frame, An automatic vegetable harvesting machine comprising a lifting frame to which a blade is attached, the angle control mechanism controlling the tilting angle of the tilting frame, and the height control mechanism controlling the lifting position of the lifting frame. The path 1 in which the cutting edge of the cutting blade moves in an arc shape from the upper position to the lower position and the path 2 in which the cutting edge moves vertically upward from the end point of the path 1 to the start point of the next path 1 are used as a cycle. It is characterized by moving.
Further, the coordinates of the cutting edge of the root cutting blade (x _W , y _W ) when the moving direction of the machine body is the x _W axis direction, and the vertical direction to the x _W axis is the y _W axis direction, and the angle control mechanism The following equation represents the relationship between the arm angle θ (t) of the tilting frame controlled by the arm length r (t) controlled by the height control mechanism
Based on
For the path 1, the coordinates of the cutting edge (x _W , y _W )
x _W (t) = X _a0 − Ra cosθ _W (t)
y _W (t) = Y _a0 − Ra sinθ _W (t)
(However, θW is
X _a0 is the initial x-coordinate value of the arc center of path 1, Y _a0 is the initial y-coordinate value of the arc center, Ra is the arc radius, xc (t) = Vc · t: Vc is the moving speed of the aircraft)
To obtain control target values r _ref (t) and θ _ref (t) in path 1,
For the path 2, the cutting edge coordinates (x _W , y _W )
x _W (t) = X _a0
(However, A is the arc depth of path 1)
To obtain control target values r _ref (t), θ _ref (t) in path 2,
Control means for controlling the angle control mechanism and the height control mechanism according to control target values derived for the paths 1 and 2 by appropriately setting the parameters X _a0 , Y _a0 , Ra, V _c , and A It is characterized by.

  According to the automatic vegetable harvesting machine according to the present invention, it is possible to remove the root cutting length variation and reliably harvest the vegetables.

It is the external appearance photograph of a vegetable automatic harvesting machine. It is explanatory drawing which shows the structure of a height control mechanism. It is explanatory drawing which shows the structure of an angle control mechanism. It is explanatory drawing which shows operation | movement of an angle control mechanism. It is explanatory drawing which shows the harvesting operation | movement of a vegetable automatic harvesting machine. It is a figure which shows the example which translates by fixing the angle of a root cutting blade. It is a figure which shows the example which moves a root cutting blade as a circular arc-shaped path | route. It is a figure which shows the coordinate system which draws a blade edge | path path | route. It is the graph of the path | route obtained using the value of Table 1. FIG. It is a figure which shows the state which orient | assigned the direction of the blade to the tangent direction with respect to the path | route. It is a figure which shows the state which made the direction of the blade different from the tangential direction. It is a figure which shows the proposal path | route provided with the circular arc path | route and the path | route which moves a blade upward. FIG. 3 is a model diagram of path 1; It is a model figure in case the initial value of y coordinate is negative. It is a model figure when a crawler moves. FIG. 3 is a model diagram of path 2; It is a graph which shows the target track | orbit of the x-axis direction of a proposal path | route. It is a graph which shows the target track | orbit of the y-axis direction of a proposal path | route. It is a graph which shows the target value of a height control mechanism. It is a graph which shows the target value of an angle control mechanism. It is a graph which shows the path | route of a blade edge | tip. It is a graph which shows the variation | change_quantity of the non-tangent direction of a conventional path | route. It is a graph which shows the variation | change_quantity of the non-tangent direction of a proposal path | route. It is a figure which shows the simulation result of the behavior of the soil in case the root cutting blade advances in soil in the conventional path | route. It is a figure which shows the simulation result of the behavior of the soil when the root cutting blade advances in the soil in the proposed route. It is a graph which shows the target value and experimental value of a height control mechanism. It is a graph which shows the target value and experimental value of an angle control mechanism. It is a graph which shows the track | orbit and target track | orbit of the real machine in x coordinate and y coordinate. It is a graph which shows the path | route of the real machine and target trajectory in xy plane. It is a histogram of the length of a spinach root about a conventional route and a proposal route. It is a graph which shows the motor torque in the conventional path | route and the proposal path | route in the case where the blade is not penetrate | invaded into soil. It is a graph which shows the motor torque in the conventional path | route at the time of making a blade penetrate | invade in soil, and a proposal path | route.

(Outline of harvester)
A harvester according to the present invention is shown in FIG. The harvesting machine has a root cutting blade 10 for performing root cutting, a height control mechanism 12 for controlling the position of the root cutting blade 10 in the height direction, an angle control mechanism 16 for controlling the posture of the root cutting blade 10, and collecting spinach. It comprises a transport mechanism 18 that transports, a crawler 20 that moves the harvester, and a laser sensor 22 that detects the ground surface position.
(Height control mechanism)
The height control mechanism 12 is shown in FIG. The height control mechanism includes a motor 12a, a feed screw 12b, an arm 12c, and a linear potentiometer 12d. A root cutting blade 10 is attached to the tip of the arm 12c, and the rotational motion of the motor is converted into a linear motion by a feed screw and the position of the arm 12c is adjusted to adjust the position of the arm 12c as shown in FIG. Move up and down.

(Angle control mechanism)
The angle control mechanism 16 is shown in FIG. The angle control mechanism 16 includes a motor 16a, a rack and pinion 16b, and an encoder 16c. Driven by two motors 16 and 16 installed in parallel, the rotational movement of the motor is converted into a linear motion by the rack and pinion 16b, and the rack connected to the height control mechanism unit 12 moves. As a result, the angle of the height control mechanism unit 12 can be adjusted around the rotation shaft 14 and can be operated as shown in FIG.

(Harvesting action)
FIG. 5 shows a conceptual diagram of the harvesting operation. In order to perform root cutting at an arbitrary position under the ground surface, the distance to the ground surface is measured by a laser sensor, and the position of the root cutting blade 10 is controlled by adjusting the arm length by the height control mechanism 12. Moreover, in order to prevent the ground surface exposure of a blade, it is necessary to advance a crawler in the state which made the angle of the blade downward, and to direct a force vertically downward (nonpatent literature 8-10). At that time, when the translation path of FIG. 6 in which the angle and the position of the root cutting blade are fixed is given, the soil may be pushed forward of the root cutting blade and it may be difficult to harvest. On the other hand, when the circular arc path as shown in FIG. 7 is given, it has been confirmed by experiments that it is difficult to push the soil forward and is advantageous for harvesting.

A: Cutting edge path (conventional path)
A coordinate system for drawing a blade path is assumed to be a coordinate system (x _W , y _W ) shown in FIG. In the harvesting device, the coordinates of the blade edge are determined by the crawler moving distance x _c (t) = V _c t, the arm angle θ (t), and the arm length r (t). The values of θ (t) and r (t) are Each is operated by an angle control mechanism and a height control mechanism.
The cutting edge coordinates (x _W , y _W ) can be expressed by the following equations from r (t), θ (t), and x _c (t).
x _W (t) = r (t) ・ sinθ (t) + x _c (t) (1)
y _W (t) = r (t) ・ cosθ (t) (2)
The conventionally used route is represented as “conventional route”.
The control target value θ (t) in the angle control mechanism and the control target value r (t) in the height control mechanism are input based on the following equations.
θ (t) = α sin 2πf t + θ ₀ (3)
r (t) = l _c (Const.) (4)
Where α [deg] and f [Hz] are the amplitude and frequency of the sine wave input, θ ₀ [deg] is the input center of the sine wave input, and t [s] is the time. In harvesting, r (t) varies with the ground surface position, but here it is assumed to be a constant value of l _c [mm] for simplicity. FIG. 9 shows a route obtained by using the expressions (1) and (2) and the values shown in Table 1. The control target value in the conventional route is a value obtained by trial and error, and evaluation of the passing volume of the root cutting blade and the behavior of the soil accompanying it is not sufficient. Therefore, in this specification, a route that is advantageous for harvesting is derived again.

(Desired route)
According to the analysis results of Fujisawa et al., It has been found that the smaller the amount of soil that can be pushed forward when the root cutting blade advances, the smoother the harvest can be (Non-Patent Document 11). For example, when the blade direction is advanced in the tangential direction with respect to the path as shown in FIG. 10 and when the blade direction is different from the advance direction as shown in FIG. The amount of soil that can be pushed away is reduced by directing the blade in the tangential direction. In this specification, it is desirable to use a cutting edge path in which the conventional arc path has a basic shape, and the position of the cutting edge follows the conventional arc path, and the cutting edge direction is always directed to the tangential direction of the arc path. A route. Therefore, the route shown in FIG. That is, in addition to the above-mentioned circular path “path 1”, a path for one cycle is generated by two paths “path 2” that moves the root cutting blade position upward. Path 2 is a path for returning the root cutting blade to the initial position. The generated route is referred to as “suggested route” in this specification.

B: Proposed route generation (coordinate specification in harvesting device)
In order for the root cutting blade to draw a target path in the coordinate system (x _W , y _W ) shown in FIG. 8, an appropriate control target value is given to each mechanism, and the coordinates and posture of the blade edge corresponding to the path are given. Must be specified. Angle mechanism rotating axis in this coordinate system is always moved x _W-axis, the crawler moves only at a constant speed in the positive direction of the x _W axis. Therefore, the crawler moving distance cannot be arbitrarily specified, and the coordinates change depending on time. Further, the posture of the root cutting blade is given by changing the angle of the arm, and the coordinate of the blade tip changes with the change, so the coordinate and posture cannot be specified independently. Due to these restrictions, it is difficult to give arbitrary coordinates and postures to the root cutting blade, and it is necessary to set a path in consideration of the restrictions. In this specification, a route is set up graphically by geometrical consideration in consideration of constraints. The outline is described below.

(Outline of coordinate setting method)
The harvesting device is a moving arm in which an arm mechanism is mounted on a carriage moved by a crawler. Path planning using a moving arm has been studied so far, and is generally performed using a redundant arm (Non-Patent Documents 12 and 13).
However, our harvesting device does not have redundancy, and values such as arm length are uniquely determined by specifying coordinates and posture. Further, since the crawler only goes straight at a constant speed and does not move backward, the movement displacement x _c (t) has a restriction of increasing monotonously. Since this restriction becomes a constraint condition, it is necessary to consider in route planning. Therefore, in this specification, the route is set by geometric considerations using the characteristics of the harvesting device. Since the crawler movement displacement x _c (t) can be observed in the setting, the coordinates and orientation corresponding to the proposed path are set as a function of x _c (t) using a geometric relationship. Thus, the values of θ (t) and r (t) can be derived by obtaining the edge coordinates taking into account the position of the crawler.

(Derivation of cutting edge coordinate formula of path 1)
A geometric model of path 1 is shown in FIG. α, β, and γ are the rotation center of the arc path, the rotation axis of the angle mechanism, and the root cutting blade tip, respectively. At this time, it is assumed that the root cutting blade is attached at right angles to the arm and the cutting edge coincides with the _yW axis. In the path 1, the condition that the direction of the cutting edge is tangential to the arc is that these three points are arranged on the same straight line, and therefore, the design parameter condition that satisfies the condition is derived. Here, there are three design parameters in the path 1, _namely , the y-coordinate Y _a0 of the arc center, the initial y-coordinate Y _{W0 of} the cutting edge, and the arc depth A. First, Y _W0 will be described. Since β, which is the rotation axis of the angle mechanism, always moves on the _xW axis, the y coordinate of the cutting edge must be set negative in order to point the cutting edge toward the ground surface. Therefore, the value of Y _W0 must be set negative. Next, Y _a0 will be described. Although it is possible in principle to take Y _a0 as negative or positive, Y _a0 must be positive due to the constraint that three points α, β, and γ are on the same straight line. To show this, consider a model when Y _a0 shown in FIG. 14 is negative. In this case, γ the beta progresses in the positive direction of the x _W axis α unless proceed x _W-axis negative direction, beta, three points γ is not able to satisfy the condition that is collinear, the cutting edge is desirable I can't draw a route. So we find that the value of Y _a0 must be positive. Also, since A is the width to draw the path from the value of Y _W0 , if it is expressed as a negative value based on Y _W0 , the necessary conditions for drawing the arc path can be summarized as follows.
Y _a0 > 0 (5)
Y _W0 <0 (6)
A <0 (7)
Three parameters, the arc radius Ra, the x-coordinate X _a0 of the arc center, and the x-coordinate X _c0 of the rotation axis, are uniquely determined by the condition that α, β, and γ are arranged on the same straight line and the design parameters that satisfy the above conditions. And can be expressed as:
These parameters are the initial coordinates in path 1.
A model when the crawler moves is shown in FIG. X _W and Y _W are the coordinates of the cutting edge, and θ _W (t) is the arm angle. Crawler movement displacement x _c (t) is based on crawler movement speed V _c and time t
x _c (t) = V _c・ t (11)
It can be expressed. Furthermore, the arm angle θ _W (t) is determined from x _c (t), X _a0 , X _c0 , and Y _a0.
It becomes. Since the distance between the arc center and the cutting edge is always Ra, the coordinates of the cutting edge can be expressed by the following equation using θ _W (t), X _a0 , and Y _a0 .
x _W (t) = X _a0 − Ra cosθ _W (t) (13)
y _W (t) = Y _a0 − Ra sinθ _W (t) (14)
The cutting edge draws a path according to these two equations.

(Derivation of cutting edge coordinate formula for path 2)
The geometric model of path 2 is shown in FIG. The route 2 is a section that moves from the end point of the route 1 to the start point of the next route 1. Therefore, y _W coordinates of the cutting edge in the path 2 has to be moved from the position Y _W0 + A to position Y _W0. At this time, the speed of moving from Y _W0 + A to Y _W0 has a degree of freedom. Therefore, assuming that X _c0 is a design parameter, it is assumed that the crawler moves by a distance X _c0 during the movement from Y _W0 + A to Y _W0 , and the y coordinate of the cutting edge is expressed by the following expression.
As a result, the cutting edge reaches Y _W0 when the crawler reaches X _c0 . On the other hand, assuming that the arm is pulled up vertically, the x-coordinate of the cutting edge does not change in path 2, and the x-coordinate of the cutting edge is
x _W (t) = X _a0 (16)
It can be expressed. From the above, the cutting edge is set to move according to the equations (16) and (15) in the path 2.

C: Target value derivation By solving the inverse problem from the geometric model shown in FIG. 13, the relationship between the control target values r (t) and θ (t) and the cutting edge coordinates (x _W , y _W ) can be expressed by the following equation.
The control target value is obtained by substituting the cutting edge coordinates derived as Expression (13), Expression (14), Expression (16), and Expression (15) into these two expressions.

D: Route comparison by simulation (route setting)
The parameters were set as shown in Table 2, and the proposed route was simulated. The parameters in Table 2 were those that had good follow-up of the mechanism in actual machine experiments to be described later. 17 and 18 show the x-axis direction target trajectory and the y-axis direction target trajectory in the proposed route. Further, the values of the height control mechanism target value r _ref and the angle control mechanism target value θ _ref obtained from the path are shown in FIGS. 19 and 20. Further, FIG. 21 shows the path of the blade edge obtained from the values of r _ref and θ _ref using the equations (13) to (16). From this, it can be confirmed that the path of the cutting edge is drawing a target arc path. Compared with the conventional route in FIG. 9, the proposed route has a large change in the y coordinate direction, and the moving distance in the x direction until θ _ref becomes 0 [deg] from the initial value is longer by 127 [mm], and the moving speed is 30 % Is slower. The time for one cycle is 2.85 [s] for the conventional route, while that for the proposed route is 4.07 [s], and the time for one cycle in the proposed route is 1.22 [s] longer.

(Evaluation of movement in non-tangential direction)
The movement amount in the moving direction with respect to the non-tangential direction of the root cutting blade in the arc path portion is evaluated. The velocity V _by (t) in the non-tangential direction can be expressed _by using the first derivative of the arm length, the arm angle, and the crawler speed in Expression (19) (Non-Patent Document 14). FIG. 22 and FIG. 23 show the amount of change in the conventional route and the proposed route.
The conventional route is accompanied by a change in the moving direction with respect to the non-tangential direction in most sections. On the other hand, V _by (t) is always 0 in the arc path portion in the target path, and it can be confirmed that the blade is directed in the tangential direction.

(Evaluation of projected volume)
The volume through which the root cutting blade passes until the angle reaches 0 [deg] from the initial value was compared. Table 3 shows the projected volume per unit length because the distance traveled by each route is different. As a result, it was confirmed that the proposed route is slightly smaller and more advantageous than the conventional route. From this, it can be expected that the performance of the proposed route is equal to or higher than that of the conventional route.

(Result of DEM analysis)
DEM was used to simulate the behavior of the soil when the root cutting blade traveled through the soil. The analysis results of each route are shown in FIGS. Focusing on the soil boundary, the inclination of the vertical axis of the auxiliary line st is φ _c = 16.51 [deg] and φ _p = 17.24 [deg] for the conventional route and the proposed route, respectively, although the proposed route is slightly disadvantageous, The difference was hardly seen. Since the slope of the soil is an index for evaluating the amount of soil pushed forward, it is considered that there is almost no difference in the amount of soil pushed in each route.

E: Evaluation by actual machine experiment (parameter correction in actual machine experiment)
The blade path is drawn with a coordinate system (x _W , y _W ) set on the ground. In this case, x _W axis of the coordinate system is parallel to the ground surface, also the angle control mechanism rotation axis is assumed to move x _W-axis. However, the actual harvesting arrangement for the pitch angle during the experiment swings, the angle is changed with respect to the ground surface, the axis of rotation deviates from the x _W axis, varies in y _W direction. Therefore, in the actual machine experiment, the set route cannot be drawn on the ground without correcting for the angle with respect to the ground surface and the fluctuation in the _yW direction. Therefore, assuming that the harvesting device fluctuated while being parallel to the ground surface, correction was made only for fluctuations in the _yW direction of the rotation axis of the angle control mechanism, but details of the correction method are omitted in this specification.

(Experimental conditions)
In the experiment, the crawler speed was set to one speed (about 60 [mm / s]), and about 5 [m] rows of spinach lines were harvested. The parameters of the route were measured with the conventional route having the lowest point at 40 [mm] below the ground surface. Since the arm length adjustment described in the section of the harvesting operation is performed, only the arm length parameter is different from the simulation, and changes with the vertical fluctuation of the harvesting device. In the proposed route, the setting parameters are the same as those used in the simulation, and after the above correction, the lowest point is 40 [mm] below the ground surface as in the conventional route. Here, the average and standard deviation of the expected root length when each path is used are shown in Table 4. In addition, the experiment was performed on the same experiment day and in the field, and the experiment was performed under conditions other than the route as much as possible.

(Target value tracking)
It is verified whether each mechanism follows the target value generated in the proposed route. The target value and experimental value of each mechanism are shown in FIGS. Further, the difference between the target value and the experimental value was taken, and the average value and standard deviation were summarized in Table 5. In FIG. 26, the angle control mechanism is always accompanied by a delay of 0.35 [s]. Since the average of the difference between the target value and the experimental value is almost 0 [deg] and the deviation is about 1.2 [deg], the angle follows with a difference of ± 1.2 [deg] from the target value. It can be confirmed. On the other hand, there was no delay in tracking the target value in the height control mechanism. Since the average is almost 0 [mm] and the deviation is about 1.3 [mm], the blade position is accompanied by a difference of about 1.3 [mm] from the target value.

The effect of the difference from the target value of the angle and position on the path is described. The coordinates of the cutting edge were obtained from the angle and position data, and compared with the proposed path. FIG. 28 shows a comparison between the actual trajectory and the target trajectory in the x and y coordinates, and FIG. 29 shows a comparison with the path in the xy plane. The difference between the x coordinate and the y coordinate from the target trajectory was taken, and the average value and standard deviation were summarized in Table 6. In the x-coordinate, the experimental value is accompanied by a deviation of about 11.3 [mm] from the target value. Since the x-coordinate deviation value obtained from the angular deviation is equal to 11.3 [mm], the influence of the angular deviation is considered to be large. Since the average value in the y coordinate is 1.3 [mm], the experimental value tends to be 1.3 [mm] deeper than the target value. The cutting edge path is calculated from the experimental values obtained using equations (13) to (16), and the results are shown in FIG. The route was not greatly deviated, and it was confirmed that the target route was roughly drawn.

(Evaluation of harvest performance)
In the proposed route, spinach recovery did not show any disadvantageous conditions for recovery such as spinach retention compared to the conventional route, and was successfully recovered as before.

(Comparison of root cutting position)
FIG. 30 shows a spinach root length histogram, and Table 7 shows the total number of spinach, the average root length, and the standard deviation. The root length standard deviation was characterized by different paths. There was a difference of 10 mm or more between the value assumed in the conventional route and the experimental result, but the difference from the assumed value in the proposed route is about 2 [mm], and the proposed route is more deviated than the conventional route. I understand that it is small. As a cause of this result, the influence of the moving speed of the root cutting blade can be considered. That is, the moving speed of the root cutting blade is about 30% slower than the conventional path in the proposed path, and it is thought that the position of the root in the soil is less likely to change by moving slowly.

(Comparison of motor torque)
In order to evaluate the resistance that the root cutting blade receives from the front in the harvest experiment of the conventional route and the proposed route, the command torque to the angle control mechanism motor was evaluated. FIG. 31 shows the command torque to the motor when the blade has not entered the soil, and FIG. 32 shows the command torque to the motor when the blade has entered the soil. When comparing the RMS values of the motor torque shown in FIGS. 31 and 32 when the blade does not enter the soil and the case where the blade enters, the conventional route is 148.1 [Nm], 135.8 [Nm], and the proposed route is 37.5. [Nm], 30.4 [Nm]. In either route, there is almost no difference in the presence or absence of the blade intrusion, and it can be seen that even when the blade is inserted into the soil, it does not receive much resistance from the soil. It is considered that the smaller the amount of soil that can be pushed away, the smaller the resisting force that is received, and it is confirmed by simulation that the amount that can be pushed away by either route is small.
In addition, it can be seen from this result that the motor torque is almost required for driving the mechanism, but paying attention to the magnitude, a large difference in the driving force is recognized. That is, it can be confirmed that the proposed route is driven with a torque that is 50% or less smaller than the conventional route. The proposed route has been confirmed to be more advantageous than the conventional route because it reduces the driving force of the angle control mechanism compared to the conventional route and has almost the same or better harvesting performance.

Claims (2)

A front part of the harvesting machine main body is provided with a tilting frame that is tilted and driven in the traveling direction of the machine body, and a lifting frame that is supported by the tilting frame so as to be movable up and down and has a root cutting blade attached to the lower end part. Automatic vegetable harvester,
An angle control mechanism that controls the tilt angle of the tilt frame, and a height control mechanism that controls the lift position of the lift frame,
A path 1 in which the cutting edge of the root cutting blade moves in an arc shape from the upper position to the lower position and a path 2 in which the cutting edge moves vertically upward from the end point of the path 1 to the start point of the next path 1 Vegetable automatic harvesting machine characterized by moving as a cycle. Coordinates of the cutting edge of the root cutting blade (x _W , y _W ) and the angle control mechanism when the moving direction of the machine body is the x _W axis direction, and the vertical direction to the x _W axis is the y _W axis direction Representing the relationship between the arm angle θ (t) of the tilting frame and the arm length r (t) controlled by the height control mechanism
Based on
For the path 1, the coordinates of the cutting edge (x _W , y _W )
x _W (t) = X _a0 − Ra cosθ _W (t)
y _W (t) = Y _a0 − Ra sinθ _W (t)
(However, θ _W is
X _a0 is the initial x-coordinate value of the arc center of path 1, Y _a0 is the initial y-coordinate value of the arc center, Ra is the arc radius, x _c (t) = V _c · t: V _c is the speed of the aircraft )
To obtain control target values r _ref (t) and θ _ref (t) in path 1,
For the path 2, the cutting edge coordinates (x _W , y _W )
x _W (t) = X _a0
(However, A is the arc depth of path 1)
To obtain control target values r _ref (t), θ _ref (t) in path 2,
Control means for controlling the angle control mechanism and the height control mechanism according to control target values derived for the paths 1 and 2 by appropriately setting the parameters X _a0 , Y _a0 , Ra, V _c , and A The vegetable automatic harvesting machine of Claim 1 characterized by these.