WO2024047395A1

WO2024047395A1 - Robot for rubber latex exploitation and method for rubber latex exploitation

Info

Publication number: WO2024047395A1
Application number: PCT/IB2022/062599
Authority: WO
Inventors: Minh Tam Do
Original assignee: Minh Tam Do
Priority date: 2022-08-29
Filing date: 2022-12-21
Publication date: 2024-03-07

Abstract

The disclosure relates to a robot for rubber latex exploitation. The robot comprises three major parts namely tapping arm (1), moving frame (2) and rail-based guide system (3); it is capable of locating bark surface, position of the previous secant, bark thickness to meet the demands of secants; it is equipped with a navigation system that enables the robot to automatically move, locate tree, position of the previous secant on the trunk to automatically perform the rubber tapping for an area covering multiple trees.

Description

Robot for rubber latex exploitation and method for rubber latex exploitation

The invention relates to a robot that is suitable for use in agriculture, forestry, particularly for latex exploitation, such as tapping or other works including measuring trunk diameter, cutting grass, collecting leaves.

Rubber tree has a significant economic importance because its latex is the primary ingredient for natural rubber production. To harvest rubber latex, a thin layer on the trunk is scraped in order that the latex flows out and is collected into the latex bowl. The incision must satisfy multiple criteria including obliquity (sideway angle of obliquity of the secant), forming a trough, stopping at front and rear waterlines, staying on the line without any deflecting or curving, precise cutting depth (the distance from the trunk's outer surface to the inner incision) and bark consumption (thickness of vertically sliced bark) of the tapped bark. Currently, most of the tapping operation is manually carried out, thus the outcome much depends on the tapping worker’s skills and experience.

Several automatic machines have been used for rubber latex exploitation (for example, tapping). Each of them is fixed on a rubber trunk. Composition of such machines comprises these three major parts: A cutter head moving up and down along a vertical slide bar, this vertical slide bar transversely move following an arch-shaped transversal slide bar fixed around the trunk perimeter. The combination of these two movements forms secant obliquity. The cutter inside the cutter head moves in and out centripetally, which forms cutting depth of the secant.

Most of the available automatic tapping machine cannot ensure cutting depth of the secant due to constant change of the bark thickness following actual conditions and life cycle of the tree meanwhile the in-and-out movement of the cutter is fixed. Moreover, there are no machines that can automatically moves, locates the tree, locates the previous secant on the trunk in order for automatic tapping to be done for an area covering multiple trees (about 600-800 trees for a rubber latex tapping shift). As well, there are no machines that can automatically collect the latex after tapping, or works in rubber cultivation process such as checking diameter of the trunk to determine time for tapping, periodical fertilization, grass cutting, collecting leaves to prevent fires, etc.

The present invention has been made in view of the circumstances described above of the available rubber latex tapping automatic machine, and the primary objective of the invention is to propose a robot for rubber latex exploitation that can meet the demands of secants, can automatically move following a predetermined order to rubber trees in an area and locate the area, e.g. secants on the trunk, for automatic tapping, and automatically collect the latex after tapping, etc. Additionally, other objectives and advantageous effects of the invention can be further clarified in the following section.

With the aforementioned objective and other objectives, the invention relates to a robot for latex exploitation. The robot comprises three major parts namely working arm, moving frame and guide system. The working arm comprises four major parts: position frame, transversal slide bar, vertical slide bar and working unit. What makes the invention different from available automatic rubber latex exploitation machine is that the robot using the position frame can locate its position compared to the tree to do the tapping. This position frame is capable of forming movement around the tree trunk for the working unit. According to a preferred embodiment, the working unit of the robot is cutter head.

Additionally, the cutter head is equipped with devices that can locate bark surface, position of the previous secant, bark thickness to meet the demands of secants.

What makes the invention further different from available automatic latex exploitation (for example, tapping) machine is that the robot is equipped with a guide system that enables the robot to automatically move, locate tree, position of the previous secant on the trunk to automatically perform the rubber latex exploitation (for example, tapping) for an area covering multiple trees. When the robot operates, the robot's tapping path is defined by the guide rails connecting each tree in the tapping area. The guide at each tree is equipped with a locating device such as limit switch, sensor, etc. in order that the robot stops at the correct location for tapping. At this point, with working arm having new altitude that is higher than the last tapping by a distance equal to bark consumption, the robot locates the new secant by leaning the pole of the working arm against a fixed bearing point relatively to the tree in every trapping operation. After determining altitude of the secant, the robot employs the position frame around the trunk perimeter to locate trunk axis. After locating the trunk axis, the robot can also determine altitude of the secant by using the cutter head assembly to determine the disparity between the uncut surface and the tapped surface. After determining position of the secant, the robot performs tapping operation by combining controlled in-and-out centripetal movement based on bark surface of the cutter in the cutter head, top-down movement of the cutter head along the vertical slide bar and the transversely alternate movement of the vertical slide bar following an arch-shaped transversal slide bar surrounding the trunk perimeter by predetermined principles, forming secant that meet the established demands.

Besides, the present invention also relates to rubber latex exploiting method using the robot according to the above aspect, comprising the following steps: locating the tree using a guide system and locating device; moving the robot to approach the base marking position; determining altitude of the new incision; positioning working arm of the robot compared to the tree trunk using the method of center concurrence; detecting bark surface; locating the previous secant; determining cutting depth based on predetermined depth relative to bark surface, or based on depth of the previous secant, or the predetermined distance from the wood layer. According to other aspects, using the aforementioned method of moving, locating tree and secant, the robot performs the latex collecting operation by a suction unit installed at the cutter head. Besides, further according to other aspects, the robot can perform works in rubber cultivation process such as checking diameter of the trunk to determine time for tapping using structure to measure trunk diameter at the defined altitude, or periodical fertilization, cutting grass, collecting leaves, etc., by corresponding structures provided on the working arm which plays the role of the working unit.

Fig.1

is a schematic view illustrating the robot for rubber latex exploitation;

Fig.2

is a schematic view illustrating an embodiment of a working arm;

Fig.2b

is a schematic view illustrating another embodiment of a working arm;

Fig.3

is a schematic view illustrating an embodiment wherein the robot specifies passage route to each rubber tree following predetermined order on a guide rail and locating devices;

Fig.4

is a schematic view illustrating an embodiment wherein the robot locates position and base height of the working arm;

Fig.5

are schematic views illustrating an embodiment wherein the robot locates the trunk axis;

Fig.6

are schematic views illustrating another embodiment wherein the robot locates the trunk axis;

Fig.7

is a schematic view illustrating an embodiment wherein the robot determines force exerted on the subject’s surface;

Fig.8

is a schematic view illustrating another embodiment wherein the robot determines force exerted on the subject’s surface;

Fig.9

Fig.10

is a schematic view illustrating an embodiment wherein the robot does the tapping;

Fig.11

is a schematic view illustrating an embodiment wherein the robot locates the previous secant;

Fig.12

is a schematic view illustrating an embodiment wherein the robot determines cutting depth based on predetermined depth relative to bark surface;

Fig.13

is a schematic view illustrating another embodiment wherein the robot determines cutting depth based on surface of the previous secant;

Fig.14

is a schematic view illustrating another embodiment wherein the robot determines cutting depth based on bark thickness;

Fig.15

is a schematic view illustrating an embodiment of a cutter head;

Figs.16 and 16b

[Figs.16 and 16b] are schematic views illustrating an embodiment of cutter head in tapping operation based on predetermined depth relative to bark surface, which is an embodiment of the cutter head locating the previous secant as well;

Figs.17 and 17b

[Figs.17 and 17b] are schematic views illustrating an embodiment of the cutter head in determining cutting depth based on surface of the previous secant;

Figs.18 and 18b

[Figs.18 and 18b] are schematic views illustrating an embodiment of the cutter head in determining cutting depth based on bark thickness.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Like reference numerals in the drawings are used to identify like or similar components. The contents described herein are for illustrative purposes only and are not intended to limit the scope of the present disclosure.

The robot according to the invention are used for multiple objectives in the areas of agriculture, forestry, such as latex exploitation. The terminology “rubber latex exploitation” can comprises various works such as tapping, checking the diameter of the trunk to determine time for tapping using structure to measure trunk diameter at the defined altitude, or periodical fertilization, cutting grass, collecting leaves, etc., by corresponding structures. In this description, according to the main embodiment, the cutter head is employed as the working unit working with other parts of the robot according to the invention for rubber tapping. However, it can be appreciated by those skilled in the art that other tapping parts can be used as replacement or in combination with the cutter head to do other works for latex exploitation. E.g., for latex suction, a suction head can be added to the cutter head and together work as working unit.

As shown in , the robot comprises three major parts namely working arm 1, moving frame 2 and guide rail 3. The working arm installed on the moving frame, can move relatively to the frame. The robot moves using battery or power source attached to the guide rail and guided by the guide rail. When the robot operates, the robot's tapping path is defined by the guide rails connecting to each other based on the order of the trees in the tapping area. The guide rail system can be installed closely to the ground or mounted along the tree at the proper height. Devices that help the robot locate the trees such as limit switches, sensors, etc. are installed on the guide rail (or on each tree). The robot moves along the guide rail and stops when approaching these devices, simultaneously its working arm approaches the position marking device 4 at each tree. Using this device, working arm of the robot determines working location on the trunk, according to the preferred embodiment, the working arm is used for rubber tapping, thereby the working arm determines altitude of the new secant by adding the height similar to the bark consumption.

Hereinafter, the present invention will be described in detail with reference to specific embodiments in the accompanying drawings, wherein the working unit is the cutter head for rubber tapping.

As shown in , the working arm comprises four major parts: position frame 5, transversal slide bar 6, vertical slide bar 7 and working unit 8.

The position frame of the robot can locate its position relatively to the trunk by putting the center of the position frame into the trunk axis using a locking mechanism.

According to an embodiment as shown in , the locking mechanism comprises locking arm 9, locking cylinder 10, locking base 11, pole 12, pole base 13, pole arm 14, pole cylinder 15. The arch-shaped transversal slide bar 6 can slide in the of the position frame 5 (also arch-shaped). This movement forms an arch sharing the same center as the position frame 5. The vertical slide bar 7 is fixed to the transversal slide bar 6. Cutter head 8 moves upward or downward along the vertical slide bar 7. According to the embodiment, there are three sets of vertical slide bars 7 installed on the transversal slide bar at different locations. The robot can tap with different arches around the trunk perimeter by changing the position of cutter head on the different sets of vertical slide bars corresponding to the arches. The arch-shaped locking bar 9 can slide in the channel of the arch-shaped lock base 11. The locking base 11 is fixed on the position frame 5. When sliding outward relatively to position frame, the locking bar 9 and position frame 5 together forms an arch around the trunk perimeter with an angle of over 180^o. The position frame 5 is connected to the pole base 13 via pole arm 14. With the actuation of the pole cylinder 15, the position frame 5 can move away or closely to the pole 12 while being mounted by the pole arm 14. The pole base 13 can move upward and downward relatively to the pole 12, thereby the whole working arm can move in the same manner.

As shown in , the position frame 5 is connected to the moving frame according to another embodiment, wherein two pole bases 13 are in rigid connection with two position frames 5, all of which are connected to the pole arm 14 by hanging the pole 12 in balance on the pole arm 14 and are guided by the pole cylinders 15, these pole cylinders 15 drive the pole arm 14 to move the position frame 5 together with the two pole bases 13 away from or closer to the moving frame, wherein, when the pole cylinders 15 pull the pole arms 14 the whole assembly of position frame, pole base and pole simultaneously elevates and moves towards the moving frame, vice versa, when the pole cylinders 15 release the pole arms 14 the whole assembly of position frame, pole base and pole simultaneously lowers and moves towards the trunk axis.

As shown in , moving frame 2 of the robot determines its movement path to reach each tree 16 following predetermined order by the guide rail 3 and locating devices 17. Based on the order on the guide rail, the robot stops at these positioned locations 17 and carries out tapping operation, then repeat at the next positioned location.

As shown in , the robot moves along the guide rail 3 and stops when it approaches locating devices 17, simultaneously the foot of the pole 12 of the robot’s working arm leans on the position marking device 4 at each tree. At this point, due to the connection between robot’s working arm and pole base 13, when the robot changes the altitude of the pole base 13 relatively to the pole 12 compared to the previous tapping with an additional height similar to the bark consumption, the robot’s working arm also changes its altitude with a corresponding height compared to the previous tapping (elevate in case of upward tapping, lower in case of downward tapping). This altitude change is performed by rotating threaded nut 18 connecting the pole base 13 with thread of the pole 12.

According to the embodiment of connecting the position frame 5 with the moving frame as shown in , the robot moves along the guide rail and stops when approaching locating devices, the pole cylinder 15 releases the pole arms14, the whole assembly of position frame, pole base and pole simultaneously lowers and moves towards trunk axis until the foot of the pole 12 of the robot’s working arm leans on the position marking device 4 at each tree and stops.

As shown in , after the altitude of the new incision is established as discussed above, the robot determines trunk axis and fix the position frame relatively to the tree trunk with the following steps using the locking mechanism of this embodiment:

Step 1: By the actuation of cylinder 15, move the position frame 5 towards the trunk axis with a distance similar to that between the primary position 4 and trunk axis. At that point, center of the position frame arch concurs with the trunk axis;

Step 2: Slide the locking arm 9 inside the lock base 11 outward relatively to the position frame 5 to, together with the position frame 5, form the arch around the perimeter of the trunk with an angle of over 180^o;

Step 3: Simultaneously move the arms of locking cylinders 10 towards the trunk axis with an equal distance until these arms form a predetermined leaning force against the trunk. Due to locking cylinders 10 forming different angles around the trunk perimeter, the said force formed by the locking cylinders’ arms locates center of the position frame 5 which is concurrent with the trunk axis.

According to another embodiment, as shown in , the locking mechanism comprises at least an arch-shaped locking arm 9 installed on position frames 5 by the axis 19 in order that this lock arm is rotatable to, together with the position frame, form an arch around the trunk perimeter with an angle of over 180 and the center concurs with that of the trunk axis; and locking cylinders 10 are provided at different locations on the position frame or locking arm around the tree trunk and form a predetermined leaning force against the trunk to locate center of the position frame 5 which concurs with that of the trunk. According to this embodiment, the robot determines trunk axis after moving the position frame 5 to concur with the trunk axis 16 by the following steps (in this embodiment the locking arm 9 does not slide in the channel of the lock base but rotates around the axis 19 on the position frame):

Step 1: Rotate two locking arms 9 with a corresponding angle to form an arch with the position frame;

Step 2: Simultaneously move the arms of locking cylinders 10 towards the trunk axis with an equal distance until these arms form a leaning force against the trunk. Due to locking cylinders 10 forming different angles around the trunk perimeter, the said force formed by the lock cylinders’ arms positions center of the position frame 5 which is concurrent with the trunk axis.

In the operation to determine trunk axis as described in the above embodiments and in the rubber tapping operation that will be described next, the robot employs the said arms to grope and detect the trunk surfaces and incisions or move the cutter by the predetermined principles. Hereinafter, embodiments in which the robot performs these operations will be described.

As shown in , the robot employs operating arm 20 guided by the motor 21 imposing a force on the surface 22. At state 1, the operating arm has not exerted a force on the surface 22. At state 2, motor 21 actuates, drives the operating arm 20 towards the surface 22 and reaches this surface. The reaction force of the motor is proportional to the current intensity provided for the motor, when the pushing arm 21 touches the surface 22 this current intensity will increase. When the power provided for the motor reaches a set value, the controller stops the motor or reverses according to the operation.

According to another embodiment, as shown in , the arm head 23 is added to the operating arm, connected to the operating arm by spring 24. A switch sensor 25 is installed on the arm head 23, activated when approaching a specific on the operating arm 20. At state 1, the operating arm has not exerted a force on the surface 22. At state 2, motor 21 drives the operating arm 20 towards the surface 22 and reaches this surface with the arm head 23. The spring 24 is subject to compression while the operating arm 20 keeps approaching the arm head 23 until the switch sensor 25 is activated. The controller, using the signals provided by the switch sensor 25, stops the motor. At this point, the compression force is still maintained due to that of the spring if the motor stops or it declines if the motor reverses.

According to another embodiment, as shown in , which is similar to the embodiment shown in , but two switch sensors 25 and 26 are attached to the arm head 23, corresponding to two states of compression of the 24. In this embodiment, when the arm head 23 leans against the surface 22 and the spring 24 is subject to compression until the switch sensor 25 is activated, then the motor stops (state 2). At this point, the compression force is still maintained by that of the spring. How the controller processes when the surface 22 changes its position is as follows:

situation 1 - the surface 22 moves away from the arm head 23: The switch sensor 25 is turned off. The controller drives the motor 21 to push the operating arm 20 to approach the surface 22 until the switch sensor 25 is activated. The controller stops the motor to maintain the force against the surface 22;

situation 2 - the surface 22 moves closer to the arm head 23: Switch sensor 26 is activated (state 3). The controller drives the motor 21 to push the operating arm 20 to move away from the surface 22 until the switch sensor 26 is turned off. The controller stops the motor to maintain the force against the surface 22.

As such, in this embodiment, if the surface 22 changes its relative position to the operating arm then the leaning force is still maintained.

With the force-controlled approaches to grope, detect trunk surfaces and incisions described above and other embodiments, the robot implements tapping operation after determining trunk axis and establishing altitude of the new incision as described in the following section.

As shown in , the arch-shaped transversal slide bar 6 can slide in the of the position frame 5 (also arch-shaped) using the driving motor 27. This movement forms an arch sharing the same center as the position frame 5, which is that of the trunk axis as well. The vertical slide bar 7 is fixed to the transversal slide bar 6. The cutter head 8 moves upward or downward along the vertical slide bar 7 using driving motor 28. In this embodiment, there are three sets of vertical slide bars 7 installed on the transversal slide bar at different locations to expand the operation range of the cutter head 8 when it is installed on different sets of vertical slide bars 7. The robot can tap with different arches around the trunk perimeter by combining movements of the transversal slide bar 6 with up-and-down movement of the cutter head 8 along the vertical slide bar 7. Using switch sensors installed on the path of the transversal slide bars 6 and/or vertical slide bars 7; by the approach of groping, detecting on surface of the trunk and incisions described above, the robot determines positions to implement tapping operations such as detecting positions on the trunk surface, detecting positions of the previous secant, measuring bark thickness to determine cutting depth, moving the cutter in and out following predetermined cutting depth, reversing the incision, move the cutter head to standard position to end the tapping operation...

During the tapping operation, the robot uses pairs operating arms to determine surfaces and cutting depth as described in the following section.

As shown in , the robot employs two operating arms 20 and 30 to detect position of the previous secant. It has been known that the incision is typically 4-7 mm away from the bark surface, thus the robot locates the previous secant by detecting the location on the truck that has an abrupt difference compared to the above-mentioned distance. When this operation is performed, with actuation of the two motors 21 and 29, two operating arms 20 and 30 press two arm heads 23 and 31 on the bark surface 22 and exert a predetermined force. A position sensor kit 32 is installed on these two operating arms. During the top-down (or vice versa) sliding movement along the bark surface, when reaching the previous secant, one of the operating arms abruptly moves 4-7 mm deeply inward due to change of bearing point. Then signals from the position sensor kit 32 are sent to the controller to locate the previous secant.

Another embodiment to locate the previous secant is based on abrupt change of position of the arm pressing on the bark in a time unit (abrupt change velocity) during its top-down (or vice versa) sliding movement along the bark surface.

An embodiment to establish altitude of the new incision is shown in as well.

After establishing altitude of the new incision, the robot determines the cutting depth by the following methods: Based on the predetermined depth relative to the bark surface, based on depth of the previous secant, or the predetermined distance from the wood layer.

Hereinafter, embodiments of the invention are described with upward tapping operation: The incision cuts off a lower part of bark, the upper part is kept for the next incision, the new incision is 1.5-2mm higher than the previous secant which is equal to bark consumption. Embodiments for downward tapping are similarly inferred.

As shown in , the robot determines cutting depth by the predetermined depth relative to the bark surface. This depth is determined by the operator by measuring bark depth with a specialized tool (bark gauge) based on different hardness between the bark and the wood surface. This depth typically ranges from 4 mm to 7 mm, depending on actual conditions and the tree’s life cycle. The cutting depth is typically 1-1.3 mm less deep than the bark depth. When tapping following a predetermined depth, the robot employs a pair of operating arms as shown in , but different in: The arm head 31 is equipped with cutter 33 and the position sensor kit 32. The position sensor kit 32 is characterized by the function that when it is activated, the driving motor 29 pushes the cutter 33 towards the trunk axis until it is deeper than the arm head 23 by a distance equal to the cutting depth. As such, during the tapping operation, the arm head 23 leans against the bark surface, the cutter 33 is always pushed deeper than the arm head 23 by a distance equal to the cutting depth, forming the incision with a predetermined depth.

As shown in , the robot determines cutting depth based on surface of the previous secant. When performing this operation, the robot employs a pair of operating arms as shown in , but different in: The arm head 23 is equipped with cutter 33 and the position sensor kit 32. The position sensor kit 32 is characterized by the function that when it is activated, the driving motor 29 pushes the cutter 33 towards the trunk axis by a distance equal to depth of the arm head 31. As such, during the tapping operation, the arm head 31 leans against the surface of the previous secant, the cutter 33 is always kept at the depth equal to that of this arm head, forming the incision with the depth concurring with the surface of the previous secant.

As shown in , the robot determines cutting depth based on the bark thickness. The rubber tree has a bark thickness of 4-7 mm, following actual conditions and life cycle of the tree, and it is regulated that the secant depth is 1-1.3 mm away from the wood surface, thus in this case the cutting depth is different in each tree. To meet this demand, the robot employs a pair of operating arms similarly to the one shown in , but different in: The arm head 23 is equipped with cutter 33, arm head 31 is equipped with surface detector head 34 and position sensor kit 32. The position sensor kit 32 is characterized by the function that when it is activated, the motor 21 drives cutter 33 towards the trunk axis with distance L deeper than the position of the detector head 34. The operation to determine cutting depth based on bark thickness is as follows:

Step 1: At the predetermined positions on the secant, motor 29 drives the surface detector head 34 towards the trunk axis with predetermined force. This force is enough to push the detector head to penetrate the bark thickness and stops when it reaches the wood surface (with greater hardness than the bark);

Step 2: Motor 29 drives the detector head 34 away from the trunk by a distance equal to L plus 1-1.3 mm. The position sensor 32 is activated. Motor 21, based on the signals from the position sensor 32, drives cutter 33 towards the trunk axis with a distance L deeper than the position of the surface detector head 34;

As such, during this operation, the cutter head is about 1-1.3 mm away from the wood surface.

With the above description, a simple method can be inferred in order that the robot performs the latex collecting by a suction unit installed in the cutter head. This unit has a suction head that coincides with bottom of the latex bowl when the cutter head moves to the corresponding position of the bowl relative to the secant.

As shown in , an embodiment of cutter head comprises the following major parts, namely vertical slide base 35, bark detector head 36, cutter 33, wood surface detector head 34 and secant surface detector head 39. The bark detector head 36 is installed on the vertical slide base 35 and moves up and down along with it. The cutter 33, wood surface detector head 34 and secant surface detector head 39 are installed on the bark detector head 36 and move in and out centripetally along with it. The cutter 33, wood surface detector head 34 and secant surface detector head 39 can move independently relative to the bark detector head 36.

As shown in and , in the method of locating the previous secant discussed above, the robot employs bark detector head 36 and cutter 33 move simultaneously towards trunk axis and stops when reaching the bark surface, maintains the compression force of the bark detector head 36 and cutter 33 against the bark surface. During the top-down movement along the bark surface, when reaching the previous secant, the cutter 33 abruptly moves 4-7 mm deeply inward due to change of bearing point meanwhile the bark detector head 36 still remains at its position. Then signals from the position sensor kit between the bark detector head 36 and the cutter 33 are sent to the controller to locate the previous secant.

As shown in and , in the tapping method based on the predetermined depth relative to the bark surface, at the starting point the robot drives the bark detector head 36 towards trunk axis and stops until it reaches the bark surface and maintain the compression force in order to keep detector head 36 in contact with the bark surface, the cutter 33 moves further relatively to the detector head 36 by a distance equal to the cutting depth, the cutter head moves by the predetermined incision, forming the secant with a predetermined depth.

As shown in Figs. 17 and 17b, in the tapping method based on the surface of the previous secant, cutter 33 and secant surface detector head 39 are equipped with position sensor kit to maintain the same moving gap during the tapping operation. At the starting point the robot drives the bark detector head 36 towards the trunk axis and stops until it reaches the bark surface and maintain the compression force in order to keep the contact, the secant surface detector head 39 moves further relatively to the detector head 36 and stops when reaching the surface of the previous secant and maintain the compression force in order to keep the contact, the position sensor kit between the cutter 33 and the secant surface detector head 39 is activated in order that the cutter 33 moves to the location of the secant surface detector head 39, thus the cutter 33 cuts the bark with a depth similarly to that of the previous secant.

As shown in Figs. 18 and 18b, in the tapping method based on the bark thickness, wood surface detector head 34 and cutter 33 are equipped with the position sensor kit to fix their positions relative to each other during the tapping operation (cutter 33 is deeper than the wood surface detector head 34 with the distance L towards the trunk axis). At the starting point the robot drives the bark detector head 36 towards the trunk axis and stops until it reaches the bark surface and maintain the compression force in order to keep the contact, wood surface detector head 34 moves further relatively to the detector head 36 and stops when reaching the trunk surface then reverses by a distance equal to L plus 1-1.3 mm, the position sensor kit between the wood surface detector head 34 and the cutter 33 is activated in order that the cutter 33 moves further than the wood surface detector head 34 towards the trunk axis with the distance L then stop. As such, when the cutter head moves, the cutter forms a secant with depth that is 1-1.3 mm away from the wood surface. Using switch sensors installed at the corresponding locations, the robot measures bark thickness at these locations and does the tapping with depth that is 1-1.3 mm away from the wood surface as described above.

According to embodiments displayed in Figs. 15-18b, any of the bark detector head 36, the cutter 37, the wood surface detector head 34, the secant surface detector head 39 may be configured following the principles described in Figs. 7-9, Figs. 11-14.

According to an embodiment, the bark detector head 36 or the secant surface detector head 39 is configured as illustrated in , namely comprising operating arm 20 guided by the motor 21 to move towards a surface 22 and touch this surface.

According to an embodiment, the bark detector head 36 and/or the secant surface detector head 39 are configured as illustrated in , namely comprising operating arm 20 connected to arm head 23 by spring 24, switch sensor 25 is connected to the arm head 23, this sensor is activated when approaching a predefined location on the operating arm 20, the operating arm 20 is guided by the motor 21 to move towards surface 22 and touch this surface.

According to an embodiment, the bark detector head 36 and/or the secant surface detector head 39 are configured as illustrated in , namely comprising operating arm 20 connected to arm head 23 by spring 24, two switch sensors 25, 26 are connected to the arm head 23, this sensor is activated when approaching a predefined location on the operating arm 20, the operating arm 20 is guided by the motor 21 to move towards surface 22 and touch this surface.

According to an embodiment, the bark detector head 36 and/or the cutter 37 and/or the secant surface detector head 39 are configured as illustrated in , namely comprising two operating arms 20 and 30 guided by two motors 21 and 29, two arm heads 23 and 31, these two operating arms are equipped with a position sensor kit 32, two operating arms are guided to determine location on the trunk where there is a change in its surface.

According to an embodiment, bark detector head 36 and/or the cutter 37 are configured as illustrated in , namely comprising two operating arms 20 and 30, two arm head 31 and 23, wherein the arm head 31 is equipped with cutter 33 and position sensor kit 32, driving motor 29 pushes the cutter 33 towards the trunk axis until it is deeper than the arm head 23 by a distance equal to the cutting depth.

According to an embodiment, the cutter 37 and/or the secant surface detector head 39 are configured as illustrated in , namely comprising two operating arms 20 and 30, two arm heads 31 and 23, wherein the arm head 23 is equipped with the cutter 33 and position sensor kit 32, driving motor 29 pushes the cutter 33 towards the trunk axis until it is deeper than the arm head 23 by a distance equal to the cutting depth.

According to an embodiment, the cutter 37 and/or the wood surface detector head 34 are configured as illustrated in , namely comprising two operating arms (20 and 30), two arm heads (31 and 23), wherein the arm head (23) is equipped with a cutter (33), the arm head (31) is equipped with a wood surface detector head (34) and a position sensor kit (32), the driving motor (21) drives the cutter (33) towards the trunk axis until it is deeper by a distance compared to the position of the detector head (34).

The method of locating surfaces can also be performed using other types of sensors such as ultrasonic sensor, infrared sensor, etc.

The method of determining moving gap relative to each other of other parts of the robot can also be performed by using motor encoders and/or servo. By receiving echo pulses, these motors can move with predefined path and/or relatively to each other of detector heads, working unit and cutter.

Using the aforementioned method of moving, locating tree and secant, the robot performs the latex collecting operation by a suction unit installed at the cutter head or works in rubber cultivation process such as checking diameter of the trunk to determine time for tapping using structure to measure trunk diameter at the defined altitude, or periodical fertilization, cutting grass, collecting leaves, etc., by corresponding structures.

Claims

A robot for rubber latex exploitation, comprising:
rail-based guide system;
moving frame (2) guided by the guide system to move to the working position;
working arm (1) connected to the moving frame (2), the working arm is configured to fix position relatively to the rubber tree trunk and form movement around the tree for working unit;
working unit is provided on the working arm.
The robot of claim 1, wherein the guide system of the robot comprises guide rails connects in succession trees in an area, the position marking devices (4) and locating devices (17) such as limit switches, sensors are provided on the guide system or on each tree for robot to stop at the expected location.
The robot of claim 1 or 2, wherein the working arm (1) is connected to the moving frame (2), wherein working arm (1) comprises:
two grooved arch-shaped position frames (5) provided in parallel based on height of the tree;
two arch-shaped transversal slide bars (6), each of which can slide in the groove of each position frame (5);
vertical slide bars (7) provided in parallel with each other, head of each vertical slide bar is fixed to a transversal slide bar in order that the vertical slide bars will move accordingly when the transversal slide bars move in the groove of the position frame (5);
wherein the position frame is configured to be fixed relatively to the tree trunk using a locking mechanism.
The robot of claim 3, wherein the locking mechanism comprises arch-shaped locking base (11) with groove connected to the position frame (5), arch-shaped locking arm (9) being able to slide in the groove of the locking base (11) to, together with the position frame, form an arch around the trunk perimeter with an angle of over 180 and the center concurs with that of the trunk; and locking cylinders (10) are provided at different locations on the position frame or locking arm around the tree trunk and form a predetermined leaning force against the trunk to locate center of the position frame (5) which concurs with that of the trunk axis.
The robot of claim 3, wherein the locking mechanism at least an arch-shaped locking arm (9) installed on position frames (5) by the axis (19) in order that this locking arm is rotatable to, together with the position frame, form an arch around the trunk perimeter with an angle of over 180 and the center concurs with that of the trunk; and locking cylinders (10) are provided at different locations on the position frame or locking arm around the tree trunk and form a predetermined leaning force against the trunk to locate center of the position frame (5) which concurs with that of the trunk axis.
The robot of any of claims 1 to 5, wherein the robot further comprises:
pole (12);
two pole bases (13) connected to two position frames (5) by two pole arms (14) provided in parallel with each other and two pole cylinders (15) provided in parallel with each other, these pole cylinders (15) drive the pole arms (14) to move the position frame (5) away or closer to the pole (12) while being mounted by the pole arm (14);
pole (12) is connected to two pole bases (13) by the manner in which two pole bases (13) can move upward and downward relatively to the pole (12), thereby the working arm can move in the same manner.
The robot of any of claims 1 to 5, wherein the robot further comprises:
pole (12)
two pole bases (13) are connected to two position frame (5), two pole bases (13) are connected to pole arm (14) by hanging the pole (12) in balance on the pole arm (14) and are guided by the pole cylinders (15), these pole cylinders (15) drive the pole arm (14) to move the position frame (5) together with the two pole bases (13) away from or closer to the moving frame, wherein, when the pole cylinders (15) pull the pole arms (14) the whole assembly of position frame, pole base and pole simultaneously elevates and moves towards the moving frame, vice versa, when the pole cylinders (15) release the pole arms (14) the whole assembly of position frame, pole base and pole simultaneously lowers and moves towards the trunk axis.
The robot of any one of the preceding claims, wherein the working unit is a cutter head.
The robot of claim 8, wherein the cutter head (8) is configured in order to move up and down along the vertical slide bar (7), comprising:
vertical slide base (35), wherein the vertical slide bar are provided through the vertical slide base in order that the vertical slide base can move up and down along the vertical slide bar (7);
bark detector head (36);
cutter (37);
wood surface detector head (38);
secant surface detector head (39);
wherein the bark detector head (36) is disposed on the vertical slide base (35) and moves up and down with the vertical slide base (35); the cutter (37), the wood surface detector head (38) and the secant surface detector head (39) are provided on the bark detector head (36) and move in and out centripetally along with this bark detector head (36) and can move independently relative to the bark detector head (36).
The robot of claim 9, wherein the bark detector head (36) or the secant surface detector head (39) is configured to comprise operating arm (20) guided by motor (21) to move towards a surface (22) and touch this surface.
The robot of claim 9, wherein the bark detector head (36) and/or the secant surface detector head (39) are configured to comprise operating arm (20) connected to arm head (23) by spring (24), switch sensor (25) is connected to the arm head (23), this sensor is activated when approaching a predefined location on the operating arm (20), the operating arm (20) is guided by the motor (21) to move towards surface (22) and touch this surface.
The robot of claim 9, wherein the bark detector head (36) and/or the secant surface detector head (39) are configured to comprise operating arm (20) connected to arm head (23) by spring (24), two switch sensors (25, 26) are connected to the arm head (23), this sensor is activated when approaching a predefined location on the operating arm (20), the operating arm (20) is guided by the motor (21) to move towards surface (22) and touch this surface.
The robot of claim 9, wherein the bark detector head (36) and/or cutter (37) and/or secant surface detector head (39) is configured to comprise two operating arms (20 and 30) guided by two motors (21 and 29), two arm heads (23 and 31), these two operating arms are equipped with a position sensor kit (32), two operating arms are guided to determine location on the trunk where there is a change in its surface.
The robot of claim 9, wherein the bark detector head (36) and/or the cutter (37) are configured to comprise two operating arms (20 and 30), two arm head (31 and 23), wherein the arm head (31) is equipped with cutter (33) and position sensor kit (32), driving motor (29) pushes the cutter (33) towards the trunk axis until it is deeper than the arm head (23) by a distance equal to the cutting depth.
The robot of claim 9, wherein cutter (37) and/or secant surface detector head (39) are configured to comprise two operating arms (20 and 30), two arm heads (31 and 23), wherein the arm head (23) is equipped with cutter (33) and position sensor kit (32), driving motor (29) pushes the cutter (33) towards the trunk axis by a distance equal to depth of the arm head (23).
The robot of claim 9, wherein the cutter (37) and/or the wood surface detector head (38) are configured to comprise two operating arms (20 and 30), two arm heads (31 and 23), wherein the arm head (23) is equipped with a cutter (33), the arm head (31) is equipped with a wood surface detector head (34) and a position sensor kit (32), the driving motor (21) drives the cutter (33) towards the trunk axis until it is deeper by a distance compared to the position of the detector head (34).
The robot of any of claims 9 to 16, wherein bark detector heads (36) and wood surface detector head (38) may be mechanical structures and/or sensors such as non-contact sensor, ultrasonic sensor, infrared sensor.
The robot of any of claims 9 to 16, wherein the robot employs motor encoders and/or servos to determine and move with predefined path and/or relatively to each other of detector heads, working unit and cutter.
The robot of any of claims 1 to 7, wherein the working unit is a structure to perform works in rubber cultivation process such as checking diameter of the trunk to determine time for tapping, periodical fertilization, grass cutting, collecting leaves.
A method for rubber latex exploitation comprises the following steps:
locating tree using the guide system and locating device;
move the robot to approach the base marking position;
determining altitude of the new secant;
positioning working arm of the robot relatively to the tree trunk using the method of center concurrence;
detecting bark surface;
locating the previous secant;
determining the cutting depth based on the predetermined depth relative to the bark surface, based on depth of the previous secant, or the predetermined distance from the wood layer.
The method of claim 20, wherein while the robot moves along the guide rail and stops when approaching locating devices at each tree, it determines altitude of the new secant by the following steps:
lift the pole of the working arm to the position marking device at each tree;
via the connection between the pole base with the pole, changing the altitude of the pole base relatively to the pole compared to the previous tapping with an additional height equal to the bark consumption, at that point the robot’s working arm also changes its altitude with a corresponding height compared to the previous tapping.
The method of claim 20, wherein, after determining tree position and secant altitude, the robot performs the process of positioning the working arm with the following steps:
using the pole cylinder to move the position frame (provided in connection with the pole base via the pole arm) towards the trunk axis with a distance similar to that between the primary position and the trunk axis, at that point center of the position frame concurs with the trunk axis;
slide the locking arm inside the lock base outward relatively to the position frame to, together with the position frame, form the arch around the perimeter of the trunk with an angle of over 180^o, rotate the locking arm around the pole on the position frame to form an arch, with the position frame, around the perimeter of the trunk with an angle of over 180^o;
simultaneously move arms of locking cylinders towards the trunk axis by an equal distance until these arms form a predetermined leaning force against the trunk, at that point, due to locking cylinders forming different angles around the trunk perimeter, the said force formed by the lock cylinders’ arms positions center of the position frame which is concurrent with the trunk axis.
The method of claim 20, wherein the robot can locate the previous secant using the structure with one or two detector heads, leaning against the bark surface to detect the location on the trunk that has an abrupt depth difference between the untapped surface and the tapped surface while moving up or down along the bark surface.
The method of any of claims 20 to 23, wherein during the tapping process the robot leans the bark detector head against the bark while the cutter is pushed deeper than the bark detector head by a distance equal to the cutting depth, forming the secant with a predetermined depth.
The method of any of claims 20 to 23, wherein during the tapping process the robot leans the secant surface detector head against the surface of the previous secant, the cutter is always kept at the depth equal to the arm head, forming the secant with the depth concurring with the surface of the previous secant.
The method of any of claims 20 to 23, wherein the robot does the tapping with a distance of D away from the wood surface by the following steps:
at the predefined location on the tapping path, the robot moves the wood surface detector head towards the trunk axis, pushes the detector head to penetrate the bark thickness and stops when it reaches the wood surface;
reverse the wood surface detector head away from the trunk by a distance equal to L plus D, then move the cutter towards the trunk axis until it is deeper by a distance L compared to the position of the detector head , forming a secant with depth that is away from the wood surface by a distance D.
The method of claim 20-26, wherein the robot performs tapping operation by combining controlled in-and-out centripetal movement based on bark surface of the cutter in the cutter head, top-down movement of the cutter head along the vertical slide bar and the transversely alternate movement of the vertical slide bar following an arch-shaped transversal slide bar surrounding the trunk perimeter by predetermined principles, forming secant that meet the predetermined demands.