Tea picking device and tea picking method using redundant degree of freedom serial-parallel robotic arms

Abstract

The present invention discloses a tea picking device and a tea picking method using a serial-parallel robotic arm with redundant degrees of freedom. In the present invention, the frame is driven to move by two mobile chassis, the translation device is driven to rise and fall by two lifting devices on the frame, and drives the static platform of the serial-parallel robotic arm to drive the picking end and the entire serial-parallel robotic arm to translate. Two joint motors 1 at both ends of the static platform in the serial-parallel robotic arm drive two active arms 1 to drive the moving platform bracket to move through two driven connecting rods. Joint motor 2 drives active arm 2 to drive the moving platform bracket to move through driven connecting rod 2. Joint motor 3 on the moving platform bracket in the picking end drives the steering gear frame to rotate. The steering gear on the steering gear frame drives the steering gear arm to drive the two blades to move relative to or opposite to each other through two connecting rods and two clamping blocks. A belt conveyor mechanism is provided on the frame at the rear of the translation device, and a material box is provided at the output end of the belt conveyor mechanism. The present invention can achieve precise picking and low-loss collection of tea buds.

Description

Technical Field

[0001] The present invention belongs to the technical field of agricultural machinery, and in particular relates to a tea picking device and a tea picking method thereof using a serial-parallel mechanical arm with redundant degrees of freedom. Background Art

[0002] In the existing automated harvesting equipment for premium teas, industrial robotic arms, as core harvesting devices, suffer from significant technical deficiencies. Specifically, traditional serial robotic arms suffer from excessively large end-effector inertia moments due to their lengthy transmission chains, resulting in reduced positioning accuracy and dynamic response hysteresis. Conventional parallel robotic arms (such as the Delta-type structure), while characterized by high motion precision and smooth operation, are limited by their inherent structural characteristics and suffer from a small effective working space. Forcibly expanding the operating range through amplification mechanisms would not only significantly increase the equipment's footprint but also disrupt the mechanical system's force balance. In tea gardens with complex terrain, the risk of equipment tipping over due to center-of-gravity shifts is significant, severely limiting the reliability and continuity of harvesting operations. Furthermore, traditional tea bud collection devices, which often utilize negative pressure adsorption, suffer from low collection efficiency and compromised bud integrity. These devices are difficult to adapt to the continuous harvesting needs of high-density tea buds and consume a lot of energy. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a tea picking device and a tea picking method using a serial-parallel robotic arm with redundant degrees of freedom.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] The present invention utilizes a tea-picking device with redundant degrees of freedom serial-parallel robotic arms, comprising a mobile chassis, a frame, serial-parallel picking robotic arms, a lifting device, a translation device, a binocular camera, and a belt conveyor. The frame is driven by two symmetrically arranged mobile chassis, and is equipped with a binocular camera and two symmetrically arranged lifting devices, which drive the translation device up and down. The belt conveyor is mounted on the frame and located behind the translation device. A material box is removably fixed to the frame at the output end of the belt conveyor. A baffle is fixed to the frame on the side of the belt conveyor away from the translation device.

[0006] The serial-parallel picking robot arm includes a serial-parallel robot arm and a picking end; the serial-parallel robot arm includes a static platform, an active arm 1, a driven link 1, an active arm 2, a driven link 2 and a dynamic platform; the static platform is driven to move by a translation device, and the translation device drives the static platform to move in a direction perpendicular to the direction of advance of the two mobile chassis drive frames and parallel to the conveying direction of the belt conveyor mechanism; one end of the two active arms 1 and the two ends of the static platform respectively form a rotating pair, and are respectively driven to rotate by two joint motors 1, and the other end is fixed with n parallel arranged rotating shafts 1, n ≥ 3; the dynamic platform includes a dynamic platform The platform bracket and the rotating part, the moving platform bracket is located below the static platform, and both ends of the moving platform bracket are fixed with n parallel arranged rotating shafts 2, and the middle part forms a rotating pair with the rotating part; there are two groups of driven link groups composed of n parallel arranged driven link 1s, and the two ends of each driven link 1 in the driven link group respectively form a ball hinge with a rotating shaft 1 and a rotating shaft 2 located on the same side; the motor bracket 1 and the static platform form a rotating pair; one end of the active arm 2 and the motor bracket 1 form a rotating pair, and are driven to rotate by the joint motor 2, and the two ends of the driven link 2 are respectively hinged to the other end of the active arm 2 and the rotating part. Among them, the rotation center axes between the two active arms 1 and the static platform, the rotation center axis between the motor bracket 1 and the static platform, the rotation center axis between the rotating part and the dynamic platform bracket, each rotation shaft 1 and each rotation shaft 2 are arranged horizontally and in parallel, the rotation center axis between the active arm 2 and the motor bracket 1 and the rotation center axes at both ends of the driven connecting rod 2 are arranged horizontally and in parallel, and are perpendicular to the rotation shaft 1, and perpendicular to the direction in which the translation device drives the series-parallel picking robot arm to translate; the picking end is installed on the dynamic platform bracket.

[0007] Preferably, the lifting device includes a handwheel, a fixed shell, a nut block, a screw and a worm, the fixed shell is fixed on the frame, the horizontally arranged worm and the fixed shell form a rotating pair, the handwheel is fixed on the worm, the vertically arranged screw and the fixed shell form a rotating pair, and a ball screw pair is formed through the ball and the nut block; the worm is engaged with the turbine fixed on the screw.

[0008] Preferably, the translation device includes a base plate, a synchronous wheel bracket, a synchronous wheel, a tensioning wheel and a synchronous belt; the two ends of the horizontally arranged base plate are fixed to the nut blocks of the two lifting devices; the synchronous wheel bracket and the base plate form a sliding pair; a synchronous wheel is hinged on the synchronous wheel bracket, and tensioning wheels are hinged on both sides of the synchronous wheel; both ends of the synchronous belt are fixed to the base plate, the synchronous wheel and the two tensioning wheels form a rolling friction pair with the synchronous belt, and the synchronous wheel is driven to rotate by a servo motor.

[0009] Preferably, the picking terminal includes a servo frame and two retractable blades. The servo frame is driven for rotation by a third joint motor, which is fixed to the dynamic platform bracket; a second baffle is fixed to the servo frame in front of the two blades. In the picking terminal, the middle portion of the servo arm forms a horizontal rotation pair with the servo frame and is driven for rotation by the servo. Both ends of the servo arm are hinged to one end of two centrally symmetrical connecting rods. The other ends of the two connecting rods are hinged to the middle portions of two axially symmetrically arranged clamping blocks. The upper ends of the two clamping blocks are both hinged to the servo frame, and the lower ends of the two axially symmetrically arranged blades are fixed.

[0010] The present invention adopts a tea picking method of a tea picking device with redundant degrees of freedom serial-parallel robotic arms, which is specifically as follows:

[0011] The two mobile chassis drive the rack to move to the tea ridge, and the two lifting devices drive the translation device and the serial-parallel picking robot arm to rise or fall, so that the height of the blade end reaches the preset initial height; the two mobile chassis drive the rack to move forward intermittently along the tea ridge, and whenever the two mobile chassis stop driving the rack, the serial-parallel picking robot arm and the translation device work to pick tea in the current working area; the tea picking process is as follows: first, the binocular camera obtains the image of the current working area, and transmits the image of the current working area to the host computer, the host computer identifies the position of the tea buds in the working area, and A set of spatial coordinates of tea bud positions is generated, wherein the spatial coordinate system takes a corner point on one side of the serial-parallel picking robot arm in the operating area as the origin O, the two mobile chassis drive the frames to move in the Y-axis direction, the translation device drives the serial-parallel picking robot arm to move in the X-axis direction, and the vertical direction is the Z-axis direction; then, based on the generated set of spatial coordinates of tea bud positions, the improved ant colony algorithm is used to obtain the overall optimal picking path of the operating area; then, according to the overall optimal picking path of the operating area, each tea bud on the optimal picking path in the current operating area is harvested.

[0012] Preferably, the process of optimizing the picking path using the improved ant colony algorithm is as follows:

[0013] (1) The operating area is divided into two low-density areas and a high-density area between the two low-density areas along the X-axis, and a transition area is divided on the side adjacent to the high-density area in the two low-density areas. The speed of the static platform in the low-density area except the transition area is , the speed in the high-density area is , the speed in the transition region is ,and , is the X-axis coordinate of the static platform when it is in the transition area, is the X-axis coordinate of the point farthest from the transition area to the high-density area; the speed of the static platform when it is located in other areas of the low-density area except the transition area and the speed when it is located in the high-density area are taken from their respective candidate sets.

[0014] (2) Parameter initialization: Set the pheromone on the path from node i to node j at the tth iteration Initial value, number of ants, pheromone weight , heuristic weight , volatility coefficient , speed influence coefficient , cross-interval penalty factor , pheromone increment adjustment coefficient ; Define the time window: , The redundant degree of freedom provided by the redundant degree of freedom expansion mechanism composed of joint motor 2, active arm 2 and driven link 2 controls the offset of the picking end in the X-axis direction. represents the X-axis coordinate of node i, On behalf of the static platform The speed at which the

[0015] (3) Defining heuristic information by integrating time cost and static platform speed , and considering the difference in the location area between node i and node j and the difference in the translation speed of the static platform at node i and node j, the modified heuristic information is defined ;

[0016] The path selection probability is

[0017]

[0018] Where, represents the set of unvisited nodes on the path from node i to node j;

[0019] (4) Selection and , calculate the velocity of the static platform when it is in the transition area , execute steps (2) and (3) to obtain the path selection probabilities of various paths from node i to node j;

[0020] (5) Update global pheromone:

[0021]

[0022] Where, represents the pheromone increment left by ant q on the path from node i to node j, and , is the number of nodes successfully picked by ant q, is the time cost of ant q on the path from node i to node j, and the benchmark speed Take speed Maximum speed in the candidate set;

[0023] After each update of the global pheromone, the path selection probability of various paths from node i to node j is recalculated;

[0024] (6) When the number of iterations is reached, the path from node i to node j with the highest probability of path selection is selected as the path and The corresponding optimal picking path;

[0025] (7) Repeat steps (4) to (6), and update and Until all and The combination of all the paths selected by the calculation is used to select the path from node i to node j with the largest probability as the final picking path from node i to node j, and the corresponding path of the final picking path is obtained. and combination;

[0026] (8) The ant starts from the starting point of the operation area and moves to the node with the largest X-axis coordinate in the operation area. Every time it generates a path from node i to node j, it uses node j as the new node i, thereby generating the overall optimal picking path for the operation area.

[0027] More preferably, the heuristic information is

[0028]

[0029] Where, express The maximum value that can be obtained from the candidate set is the time difference between the ant's journey from node i to node j. , the time cost of ant q on the path from node i to node j , Represents the distance in the X-axis direction of the constant speed section of the path from node i to node j, and the speed of the static platform when it is in the constant speed section of the path from node i to node j , and They represent the starting X-axis coordinates and the ending X-axis coordinates of the speed change section in the path from node i to node j, and the speed of the static platform when it is in the speed change section in the path from node i to node j. , the total harvesting time of each node in the path from node i to node j , n is the total number of nodes in the path from node i to node j, is the harvesting time at node p, including picking and throwing time.

[0030] More preferably, the modified heuristic information is

[0031]

[0032] Where, is the speed difference weight, There are regional differences, and , express The minimum value that can be obtained from the candidate set.

[0033] Preferably, the process of harvesting the tea buds on the overall optimal picking path in the current operation area according to the overall optimal picking path of the operation area is as follows: the translation device drives the static platform to drive the entire serial-parallel picking robot arm to translate along the X-axis direction, so that the two blade end midpoints of the picking end are translated in sequence to the X-axis coordinate positions of the positions of the tea buds on the overall optimal picking path of the operation area, and the serial-parallel picking robot arm translates along the X-axis direction according to the corresponding speed calculated in step (7) on each final picking path; the serial-parallel picking robot arm translates along While translating in the X-axis direction, the two joint motors drive the corresponding active arm to rotate, and each active arm drives the platform bracket and the picking end to move in a vertical plane parallel to the YOZ plane through the corresponding driven link group, so that the two blade end centering points of the picking end are translated in sequence to the Y-axis coordinate position of each tea bud position on the overall optimal picking path of the operation area, and the distance deviation between the two blade end centering points of the picking end and the tea bud position in the X-axis and Y-axis directions is calculated in real time. When the distance deviation in the Y-axis direction is not within the preset When the deviation range is reached, the joint motor 2 drives the active arm 2 to rotate the driven link 2, and the driven link 2 drives the picking end to adjust along the X-axis direction through the dynamic platform bracket, so that the distance deviation in the X-axis direction is within the preset deviation range. If the distance deviation in the Y-axis direction is not within the preset deviation range, the two joint motors 1 drive the corresponding active arm 1 to rotate for adjustment; when the center point of the two blade ends of the picking end reaches the tea bud position, the servo drives the servo arm to rotate forward, and the servo arm drives the lower ends of the two clamps to move toward each other through the two connecting rods, thereby driving the two The ends of the blades are closed to shear the tea buds, completing the picking of the tea buds; then the three-drive servo frame of the joint motor drives the tea buds to rotate in the direction close to the belt conveyor mechanism, and the tea buds are thrown onto the conveyor belt of the belt conveyor mechanism through centrifugal force. The belt conveyor mechanism transports the tea buds into the material box, completing the collection of the tea buds; then the controller controls the three-drive servo frame of the joint motor to drive the tea buds to rotate in the direction away from the belt conveyor mechanism to the original position, and at the same time controls the servo to drive the servo arm to reverse, and the servo arm drives the two clamps and the two blades to move back to the original position through two connecting rods.

[0034] The present invention has the following beneficial effects:

[0035] The present invention can realize the accurate picking and low-loss collection of tea buds; specifically, the present invention adopts the combination of a translation device and a serial-parallel robotic arm with redundant degrees of freedom, and on the basis of the picking path optimized by the improved ant colony algorithm, the translation device drives the serial-parallel robotic arm to drive the picking end to translate along the X-axis direction, and the two joint motors at both ends of the static platform in the serial-parallel robotic arm drive the two active arms and drive the moving platform bracket and the picking end to move in a vertical plane parallel to the YOZ plane through two driven connecting rod groups, so that the picking end moves to the tea bud position on the picking path, and the joint motor 2 in the serial-parallel robotic arm drives the active arm 2 to drive the moving platform bracket and the picking end to perform real-time fine-tuning along the X-axis direction through the driven connecting rod 2, thereby realizing dynamic compensation of the position of the picking end in the X-axis direction, and the translation device can maintain continuous driving in one direction, avoiding frequent changes in the translation device. The picking end position is adjusted by rapid or repeated start and stop, which reduces the inertial impact of the translation device, improves the overall operation stability, and eliminates the positioning jitter caused by emergency stop. Through this "main frame (composed of a translation device, a static platform, a dynamic platform bracket, two joint motors, two active arms and two driven connecting rod groups) coarse positioning + redundant degree of freedom expansion mechanism (composed of motor bracket one, active arm two, driven connecting rod two and rotating parts) fine adjustment" collaborative motion mode, the translation device can maintain continuous driving in one direction to improve efficiency while also achieving precise positioning of the tea bud position, thereby enabling accurate picking of the tea buds. Among them, in the picking path planning optimized by the improved ant colony algorithm, the time window constraint and real-time feedback mechanism are combined, so that the path for picking according to the optimal path takes into account both time and success rate, further improving the picking efficiency. Furthermore, the present invention adopts the method of throwing tea buds to realize the collection of tea buds. When the picking end completes the picking of tea buds, the controller controls the three-drive servo frame of the joint motor to drive the tea buds to rotate in the direction close to the belt conveyor mechanism, and throws the tea buds onto the conveyor belt of the belt conveyor mechanism through centrifugal force. The tea buds are transported to the material box through the belt conveyor mechanism to realize the collection of tea buds. Compared with the existing negative pressure adsorption method, the method avoids the problems of breakage and abrasion of tea buds caused by collision and friction with the tube wall (the centrifugal force size is pre-debugged and designed, and the collision force received by the tea buds when they are thrown onto the conveyor belt of the belt conveyor mechanism can be very small), there is no need to maintain continuous airflow pressure, the power consumption is low, and the structure is simple and easy to maintain. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0037] Figure 2 It is a structural schematic diagram of the lifting device in the present invention.

[0038] Figure 3Schematic diagram of the structure of the translation device in the present invention.

[0039] Figure 4 This is a schematic diagram of the structure of the series-parallel picking robotic arm in the present invention.

[0040] Figure 5 It is a structural schematic diagram of the moving platform and the picking end of the present invention.

[0041] Figure 6 This is a schematic diagram of the structure of the picking end when the blade is closed in the present invention.

[0042] Figure 7 This is a schematic diagram of the structure of the picking end when the blade is opened in the present invention.

[0043] Figure 8 This is a flowchart of the improved ant colony algorithm for optimizing the picking path in the present invention.

[0044] Figure 9 Schematic diagram of the division of the working area in the present invention.

[0045] Figure 10 Schematic diagram of the structure of the serial-parallel picking robot arm during the X-axis compensation operation of the present invention Figure 1 .

[0046] Figure 11 Schematic diagram of the structure of the serial-parallel picking robot arm during the X-axis compensation operation of the present invention Figure 2 . DETAILED DESCRIPTION

[0047] The present invention will be further described below with reference to the accompanying drawings.

[0048] like Figure 1 As shown, the present invention uses a tea picking device with redundant degrees of freedom serial-parallel manipulators, comprising a mobile chassis 1, a frame 2, a material box 3, a serial-parallel picking manipulator 4, a lifting device 5, a translation device 6, a binocular camera 7, and a belt conveyor 8. The frame 2 is driven and moved by two symmetrically arranged mobile chassis 1, and two symmetrically arranged lifting devices 5 are provided on the frame 2. The two lifting devices 5 drive the translation device 6 to rise and fall, and the translation device 6 drives the serial-parallel picking manipulator 4 to translate. The belt conveyor 8 is provided on the frame 2 and is located behind the translation device 6. The material box 3 is detachably fixed to the output end of the belt conveyor 8 on the frame 2. A baffle 9 is fixed to the side of the belt conveyor 8 away from the translation device 6 on the frame 2. The baffle 9 is used to prevent tea buds from falling outside the belt conveyor 8 when the serial-parallel picking manipulator 4 throws them toward the belt conveyor 8. The binocular camera 7 is provided on the frame 2 for capturing images of the tea field operation area. The translation device 6 drives the serial-parallel picking robot arm 4 to translate in a direction perpendicular to the direction in which the two mobile chassis 1 drive the frame 2 to move forward, and is parallel to the conveying direction of the belt conveyor mechanism 8 .

[0049] like Figure 2 As shown, the lifting device 5 includes a handwheel 5-1, a fixed shell 5-2, a nut block 5-3, a screw 5-4 and a worm 5-5. The fixed shell 5-2 is fixed on the frame 2. The horizontally arranged worm 5-5 and the fixed shell 5-2 form a rotating pair. The handwheel 5-1 is fixed to the worm 5-5; the vertically arranged screw 5-4 and the fixed shell 5-2 form a rotating pair, and form a ball screw pair with the nut block 5-3 through the ball; the worm 5-5 is engaged with the turbine fixed on the screw 5-4.

[0050] like Figure 3 As shown, the translation device 6 includes a base plate 6-1, a synchronous wheel bracket 6-4, a synchronous wheel 6-6, a tensioning wheel 6-7 and a synchronous belt 6-8; the two ends of the horizontally arranged base plate 6-1 are fixed to the nut blocks 5-3 of the two lifting devices 5; the synchronous wheel bracket 6-4 and the base plate 6-1 form a sliding pair; a synchronous wheel 6-6 is hinged on the synchronous wheel bracket 6-4, and tensioning wheels 6-7 are hinged on both sides of the synchronous wheel 6-6; one end of the synchronous belt 6-8 is fixed to a fixed base 6-2, and the other end passes through the bottom end of one of the tensioning wheels 6-7, the top end of the synchronous wheel 6-6 and the bottom end of the other tensioning wheel 6-7 in turn, and is fixed to the other fixed base 6-2, and the two fixed bases 6-2 are both fixed on the base plate 6-1; the synchronous wheel 6-6 and the two tensioning wheels 6-7 all form a rolling friction pair with the synchronous belt 6-8, and the synchronous wheel 6-6 is driven to rotate by the servo motor 6-5.

[0051] like Figure 4 and Figure 5As shown, the serial-parallel picking robot arm 4 includes a serial-parallel robot arm and a picking end 4-11; the serial-parallel robot arm includes a static platform 4-1, an active arm 1 4-2, a driven link 1 4-3, a motor bracket 1 4-6, an active arm 2 4-8, a driven link 2 4-9 and a dynamic platform 4-10; the static platform 4-1 is fixed on the synchronous wheel bracket 6-4; one end of the two active arms 1 4-2 and the two ends of the static platform 4-1 respectively form a rotating pair, and are driven to rotate by two joint motors 1 4-4 respectively, and the other end is fixed with three parallel arranged rotating shafts 1; the dynamic platform 4-10 includes a dynamic platform bracket 4-10-1 and a rotating member 4-10-3, and the dynamic platform bracket 4-10-1 is located below the static platform 4-1, and Three rotating shafts 2 4-10-5 arranged in parallel are fixed at both ends of the dynamic platform bracket 4-10-1, and the middle part forms a rotating pair with the rotating member 4-10-3; there are two groups of driven link groups consisting of three driven link 1 4-3 arranged in parallel, and the two ends of each driven link 1 in the driven link group respectively form ball hinges with a rotating shaft 1 and a rotating shaft 2 4-10-5 located on the same side through two fisheye bearings; the motor bracket 1 4-6 and the static platform 4-1 form a rotating pair; one end of the active arm 2 4-8 and the motor bracket 1 4-6 form a rotating pair, and are driven to rotate by the joint motor 2 4-7, and the two ends of the driven link 2 4-9 are hinged to the other end of the active arm 2 4-8 and the rotating member 4-10-3 respectively. Among them, the rotation center axis between the two active arms 4-2 and the static platform 4-1, the rotation center axis between the motor bracket 4-6 and the static platform 4-1, the rotation center axis between the rotating part 4-10-3 and the dynamic platform bracket 4-10-1, each rotation shaft 1 and each rotation shaft 2 4-10-5 are arranged horizontally and in parallel, the rotation center axis between the active arm 2 4-8 and the motor bracket 1 4-6 and the rotation center axis at both ends of the driven connecting rod 2 4-9 are arranged horizontally and in parallel, and are perpendicular to the rotation shaft 1, and perpendicular to the direction in which the translation device 6 drives the static platform 4-1 to translate.

[0052] like Figure 6 and Figure 7As shown, the picking end 4-11 includes a servo frame 4-11-4, a servo arm 4-11-6, a connecting rod 4-11-7, a clamping block 4-11-8, a baffle 2 4-11-9 and a blade 4-11-10. The servo frame 4-11-4 is driven to rotate by the joint motor three 4-11-2, and the joint motor three 4-11-2 is fixed to the moving platform bracket 4-10-1; the middle part of the servo arm 4-11-6 and the servo frame 4-11-4 form a horizontal rotation pair, and is driven to rotate by the servo 4-11-5, and the two ends are respectively hinged to one end of two connecting rods 4-11-7 arranged in a central symmetrical manner, and the other ends of the two connecting rods 4-11-7 are hinged to the middle parts of two clamping blocks 4-11-8 arranged in an axially symmetrical manner, and the upper ends of the two clamping blocks 4-11-8 are both hinged to the servo frame 4-11-4, and two blades 4-11-10 arranged in an axially symmetrical manner are fixed to the lower ends, and a baffle two 4-11-9 is fixed to one side of the two blades 4-11-10 on the servo frame 4-11-4, and the baffle two is located on the side of the two blades 4-11-10 away from the belt conveyor mechanism 8.

[0053] As a preferred embodiment, the fixed shell 5-2 is fixed to the frame 2 through the chassis 5-6.

[0054] As a preferred embodiment, two guide rails 6-9 arranged in parallel and at intervals are fixed on the base plate 6-1, the two guide rails 6-9 and the two sliders 6-10 respectively constitute sliding pairs, and the synchronous wheel bracket 6-4 and the two sliders 6-10 are fixed.

[0055] As a preferred embodiment, both ends of the synchronous belt 6-8 are fixed by two synchronous belt pressure plates 6-3 and two fixed bases 6-2 respectively.

[0056] As a preferred embodiment, the motor bracket 4-6 is supported on the static platform 4-1 through a slewing bearing 4-5.

[0057] As a preferred embodiment, the rotating member 4-10-3 is supported on the moving platform bracket 4-10-1 through the rotary bearing 2 4-10-2.

[0058] More preferably, the outer ring of the slewing bearing 2 4-10-2 is embedded in the bearing hole opened on the moving platform bracket 4-10-1, and is axially limited by the bearing end cover 4-10-4 fixed on the moving platform bracket 4-10-1 and the transition step surface in the bearing hole. The inner ring is fixed to the optical axis section at one end of the threaded rod, and the threaded section at the other end of the threaded rod is connected to the rotating part 4-10-3 by threads.

[0059] As a preferred embodiment, the shell of the joint motor three 4-11-2 is fixed to the dynamic platform bracket 4-10-1 through the motor bracket two 4-11-1, and the output shaft of the joint motor three 4-11-2 is fixed to the servo frame 4-11-4 through the motor flange 4-11-3.

[0060] Among them, the servo motor 6-5, joint motor 2 4-7, joint motor 3 4-11-2, steering gear 4-11-5 and two joint motors 1 4-4 are all controlled by the controller, the signal output end of the binocular camera 7 is connected to the controller, and the controller communicates with the host computer.

[0061] The present invention adopts a tea picking method of a tea picking device with redundant degrees of freedom serial-parallel robotic arms, which is specifically as follows:

[0062] The two mobile chassis 1 drive the frame 2 to move to the tea ridge, and manually and synchronously rotate the two hand wheels 5-1 forward or reverse (performed by two staff members). Each hand wheel 5-1 drives the nut block 5-3 to rise or fall through the corresponding worm 5-5, worm gear and screw 5-4, and then drives the translation device 6 and the serial-parallel picking robot arm 4 to rise or fall through the two nut blocks 5-3, so that the height of the end of the blade 4-11-10 reaches the preset initial height; the two mobile chassis 1 drive the frame 2 to advance intermittently along the tea ridge, and whenever the two mobile chassis 1 stop driving the frame 2, the serial-parallel picking robot arm 4 and the translation device 6 work to carry out tea picking in the current working area. The tea picking process is as follows: first, the binocular camera 7 obtains the image of the current working area, and The image of the domain is transmitted to the host computer, which identifies the tea bud position in the operation area and generates a set of spatial coordinates of the tea bud position, wherein the spatial coordinate system takes a corner point on the operation area close to the serial-parallel picking robot arm 4 as the origin O, the two mobile chassis 1 drive the frame 2 to move in the Y-axis direction, the translation device 6 drives the serial-parallel picking robot arm 4 to translate in the X-axis direction, and the vertical direction is the Z-axis direction; then, based on the generated set of spatial coordinates of the tea bud position, the improved ant colony algorithm is used to obtain the overall optimal picking path of the operation area; then, according to the overall optimal picking path of the operation area, each tea bud on the overall optimal picking path in the current operation area is harvested (after harvesting, the translation device 6 drives the serial-parallel picking robot arm 4 to return to the initial position).

[0063] Among them, such as Figure 8 As shown in the figure, the process of obtaining the optimal picking path using the improved ant colony algorithm is as follows:

[0064] (1) If Figure 9As shown, the operating area is divided into two low-density areas and a high-density area between the two low-density areas along the X-axis according to the distribution characteristics of tea buds (high density in the middle and low density on both sides), and a transition area is divided on the side adjacent to the high-density area in the two low-density areas. The size ranges of the two low-density areas are [0, 0.4m] and [1.1m, 1.5m], respectively, where m is the unit meter. The size ranges of the transition areas within the two low-density areas are [0.3m, 0.4m] and [1.1m, 1.2m], respectively, and the size range of the high-density area is (0.4m, 1.1m). The speed of the static platform 4-1 when it is located in the low-density area except the transition area is , the speed in the high-density area is , the speed in the transition region is ,and , is the X-axis coordinate of the static platform 4-1 when it is in the transition area, is the X-axis coordinate of the point farthest from the high-density area in the transition area, that is or ; The speed of the static platform 4-1 when it is located in the low-density area except the transition area Select a value from the candidate set {0.1m / s, 0.12m / s, 0.14m / s}, where m / s is meter per second, and is the speed in a high-density area. Select a value from the candidate set {0.05m / s, 0.07m / s, 0.09m / s}.

[0065] (2) Parameter initialization: Let the pheromone on the path from node i to node j at the tth iteration be ,set up Initial value of , the number of ants m=20, the pheromone weight in the weight parameter , heuristic weight , volatility coefficient , speed influence coefficient in dynamic parameters , cross-interval penalty factor , pheromone increment adjustment coefficient ; Define the time window: , which is used to constrain the time it takes for the ant to reach node i from the previous node at node i (the i-th tea bud), ensuring that the path selection meets the time limit. The redundant degree of freedom provided by the redundant degree of freedom expansion mechanism composed of the joint motor 2, the active arm 2 4-8 and the driven link 2 4-9 controls the offset of the picking end 4-11 in the X-axis direction, and , represents the X-axis coordinate of node i, On behalf of the static platform 4-1 The speed at which the

[0066] (3) Combining the time cost and the static platform 4-1 speed, the heuristic information is defined as

[0067]

[0068] In the formula, the heuristic information is defined as represents the attraction from node i to node j, express The maximum value that can be obtained from the candidate set, in this embodiment , represents the time cost from node i to node j, represents the time difference of the ant from node i to node j, and , Represents the distance in the X-axis direction of the constant speed section in the path from node i to node j, represents the speed of the stationary platform 4-1 in the constant speed section of the path from node i to node j, and , and They represent the X-axis coordinates of the starting point (starting node) and the ending point (ending node) of the speed change section in the path from node i to node j, represents the speed of the stationary platform 4-1 when it is in the speed change section of the path from node i to node j, and , , n is the total number of nodes in the path from node i to node j, is the harvesting time at node p, including picking and throwing time, and ;

[0069] Considering the difference in the location area between nodes i and j and the difference in the translation speed of the static platform 4-1 at nodes i and j, the corrected heuristic information is

[0070]

[0071] Where, is the speed difference weight, and =0.2, There are regional differences, and , express The minimum value that can be obtained from the candidate set, in this embodiment ;

[0072] The path selection probability is

[0073]

[0074] Where, Represents the set of unvisited nodes on the path from node i to node j.

[0075] (4) Selection and , calculate the velocity of the static platform when it is in the transition area , execute steps (2) and (3) to obtain the path selection probabilities of various paths from node i to node j.

[0076] (5) Update global pheromone

[0077]

[0078] Where, represents the pheromone increment left by ant q on the path from node i to node j, and , is the number of nodes successfully picked by ant q (that is, the number of nodes passed by the path from node i where ant q is located to node j), and the time cost of ant q on the path from node i to node j , As the reference speed, the maximum speed of the static platform 4-1 when moving horizontally is 0.14m / s.

[0079] Each time the global pheromone is updated, the path selection probabilities of various paths from node i to node j are recalculated.

[0080] (6) Reaching the number of iterations The path from node i to node j with the highest path selection probability is selected as the and The corresponding optimal picking path.

[0081] (7) Repeat steps (4) to (6), and update and Until all and The combination of all the paths selected by the calculation is used to select the path from node i to node j with the largest probability as the final picking path from node i to node j, and the corresponding path of the final picking path is obtained. and combination.

[0082] (8) Ants from the starting point Start (that is, at the initial time, node i is ), until the node with the largest X-axis coordinate in the operation area, each time a path from node i to node j is generated, node j is used as the new node i to generate the overall optimal picking path for the operation area.

[0083] The process of harvesting each tea bud on the overall optimal picking path in the current operation area according to the overall optimal picking path of the operation area is as follows: the controller controls the servo motor 6-5 to drive the synchronous wheel 6-6 to rotate, and the synchronous wheel 6-6 and the synchronous belt 6-8 form a rolling friction pair, thereby driving the synchronous wheel bracket 6-4 to translate along the X-axis direction, and the synchronous wheel bracket 6-4 drives the entire serial-parallel picking robot arm 4 to translate along the X-axis direction through the static platform 4-1, so that the two blades 4-11-10 end center points of the picking end 4-11 are translated in sequence to the X-axis coordinate positions of each tea bud position (node ​​position) on the overall optimal picking path of the operation area, and the serial-parallel picking robot arm 4 translates along the X-axis direction according to the corresponding speed calculated in step (7) on each final picking path; while the serial-parallel picking robot arm 4 translates along the X-axis direction, the controller controls the two joint motors 4-4 to drive the corresponding active arm 4-2 to rotate, and each active arm 4-2 drives the dynamic platform bracket 4-10-1 and the picking robot arm 4 through the corresponding driven link group. The end 4-11 moves in a vertical plane parallel to the YOZ plane, so that the end centering points of the two blades 4-11-10 of the picking end 4-11 are sequentially translated to the Y-axis coordinate positions of the positions of the tea buds on the overall optimal picking path of the operation area, and the end centering points of the two blades 4-11-10 of the picking end 4-11 are calculated in real time (the position images of the end centering points of the two blades 4-11-10 of the picking end 4-11 can be obtained in real time by the binocular camera 7) and the positions of the tea buds in the X-axis direction and the Y-axis direction. If the distance deviation in the X-axis direction is not within the preset deviation range, the controller controls the joint motor 2 to drive the active arm 2 4-8 to drive the driven link 2 4-9 to rotate, and the driven link 2 4-9 drives the picking end 4-11 to adjust along the X-axis direction through the dynamic platform bracket 4-10-1, so that the distance deviation in the X-axis direction is within the preset deviation range. If the distance deviation in the Y-axis direction is not within the preset deviation range, the two joint motors 1 4-4 drive the corresponding active arm 1 4-2 to rotate and adjust, such as Figure 10 and Figure 11As shown; when the midpoints of the two blades 4-11-10 at the picking end 4-11 reach the tea bud position, the controller controls the servo 4-11-5 to drive the servo arm 4-11-6 to rotate forward, and the servo arm 4-11-6 drives the lower ends of the two clamping blocks 4-11-8 to move toward each other through the two connecting rods 4-11-7, thereby driving the ends of the two blades 4-11-10 to close and shear the tea buds, completing the picking of the tea buds. At the same time, the two closed blades 4-11-10 and the baffle 2 4-11-9 form a three-sided closed accommodating chamber for temporary storage of the tea buds. Then the controller controls the joint motor 3 4-11-2 to drive the servo The frame 4-11-4 drives the tea buds to rotate in the direction close to the belt conveyor mechanism 8, and throws the tea buds onto the conveyor belt of the belt conveyor mechanism 8 through centrifugal force. The belt conveyor mechanism 8 transports the tea buds to the material box, completing the collection of the tea buds; then the controller controls the joint motor three 4-11-2 to drive the steering gear frame 4-11-4 to drive the tea buds to rotate in the direction away from the belt conveyor mechanism 8 to the original position, and at the same time controls the steering gear 4-11-5 to drive the steering gear arm 4-11-6 to reverse, and the steering gear arm 4-11-6 drives the two clamping blocks 4-11-8 and the two blades 4-11-10 to move back to the original position through the two connecting rods 4-11-7.

Claims

1. A tea picking device using a series-parallel robotic arm with redundant degrees of freedom, comprising a lifting device, a translation device, and a belt conveyor mechanism, characterized in that: It also includes a serial-parallel picking robot arm; a binocular camera and two lifting devices for driving the translation device to rise and fall are provided on the frame; the belt conveyor mechanism is located behind the translation device; a baffle is fixed on the frame on the side of the belt conveyor mechanism away from the translation device; The serial-parallel picking robot arm includes a serial-parallel robot arm and a picking end; the serial-parallel robot arm includes a static platform and a dynamic platform; the static platform is driven to translate by a translation device, and the direction is perpendicular to the direction of advance of the frame; one end of the two active arms and the two ends of the static platform respectively form a rotating pair, and are driven to rotate by two joint motors, and the other end is fixed with n parallel rotating shafts, n ≥ 3; the dynamic platform includes a dynamic platform bracket, the dynamic platform bracket is located below the static platform, and both ends of the dynamic platform bracket are fixed with n parallel rotating shafts, and the middle part forms a rotating pair with the rotating part; there are two groups of driven link groups composed of n parallel driven link groups, and the two ends of each driven link in the driven link group are connected to a rotating shaft located on the same side. and a rotating shaft 2 respectively form a ball hinge; the motor bracket 1 and the static platform form a rotating pair; one end of the active arm 2 and the motor bracket 1 form a rotating pair, and are driven to rotate by the joint motor 2, and the two ends of the driven link 2 are hinged to the other end of the active arm 2 and the rotating member respectively; wherein, the rotation center axes between the two active arms 1 and the static platform, the rotation center axis between the motor bracket 1 and the static platform, the rotation center axis between the rotating member and the dynamic platform bracket, each rotating shaft 1 and each rotating shaft 2 are horizontally and parallelly arranged, the rotation center axis between the active arm 2 and the motor bracket 1 and the rotation center axes at both ends of the driven link 2 are horizontally and parallelly arranged, and are perpendicular to the rotating shaft 1, and perpendicular to the direction in which the translation device drives the serial-parallel picking robot arm to translate; the picking end is installed on the dynamic platform bracket; The two joint motors drive the corresponding active arm one to rotate, and each active arm one drives the dynamic platform bracket and the picking end to move in a vertical plane parallel to the YOZ plane through the corresponding driven link group; the joint motor two drives the active arm two to rotate and the driven link two drives the picking end to adjust along the X-axis direction through the dynamic platform bracket; the spatial coordinate system takes a corner point on the side of the serial-parallel picking robot arm in the working area as the origin O, the direction of the frame's forward movement is the Y-axis direction, the direction of the translation device driving the serial-parallel picking robot arm to translate is the X-axis direction, and the vertical direction is the Z-axis direction.

2. The tea picking device using a series-parallel robotic arm with redundant degrees of freedom according to claim 1, characterized in that: The lifting device includes a handwheel, a fixed shell, a nut block, a screw and a worm. The fixed shell is fixed on the frame. The horizontally arranged worm and the fixed shell form a rotating pair. The handwheel is fixed on the worm. The vertically arranged screw and the fixed shell form a rotating pair, and a ball screw pair is formed through the ball and the nut block; the worm is engaged with the turbine fixed on the screw.

3. The tea picking device using a series-parallel robotic arm with redundant degrees of freedom according to claim 1, characterized in that: The translation device includes a base plate, a synchronous wheel bracket, a synchronous wheel, a tensioning wheel and a synchronous belt; the two ends of the horizontally arranged base plate are fixed to the nut blocks of the two lifting devices; the synchronous wheel bracket and the base plate form a sliding pair; the synchronous wheel bracket is hinged on the synchronous wheel bracket, and tensioning wheels are hinged on both sides of the synchronous wheel; both ends of the synchronous belt are fixed to the base plate, the synchronous wheel and the two tensioning wheels form a rolling friction pair with the synchronous belt, and the synchronous wheel is driven to rotate by a servo motor.

4. The tea picking device using a series-parallel robotic arm with redundant degrees of freedom according to claim 1, characterized in that: The picking end includes a servo frame and two openable and closable blades; the servo frame is driven to rotate by joint motor three, and joint motor three is fixed to the dynamic platform bracket; a baffle two is fixed on the servo frame in front of the two blades; in the picking end, the middle part of the servo arm and the servo frame form a horizontal rotating pair, and are driven to rotate by the servo, and the two ends are respectively hinged to one end of two connecting rods arranged in a central symmetrical manner, and the other ends of the two connecting rods are hinged to the middle parts of two clamping blocks arranged in an axially symmetrical manner, the upper ends of the two clamping blocks are hinged to the servo frame, and the lower ends are fixed with two blades arranged in an axially symmetrical manner.

5. The tea picking method according to claim 4, wherein: The details are as follows: Two mobile chassis drive the frame to move to the tea ridge, and two lifting devices drive the translation device and the serial-parallel picking robot arm to rise or fall, so that the height of the blade end reaches the preset initial height; Two mobile chassis drive the frames to advance intermittently along the tea ridges, and whenever the two mobile chassis stop driving the frames, the serial-parallel picking robotic arms and the translation device work to carry out tea picking in the current operation area; the tea picking process is as follows: first, the binocular camera acquires the image of the current operation area and transmits the image of the current operation area to the host computer, the host computer identifies the position of the tea buds in the operation area, and generates a set of spatial coordinates of the tea bud positions, wherein the spatial coordinate system takes a corner point on the side of the operation area close to the serial-parallel picking robotic arms as the origin O, the direction in which the two mobile chassis drive the frames to advance is the Y-axis direction, the direction in which the translation device drives the serial-parallel picking robotic arms to translate is the X-axis direction, and the vertical direction is the Z-axis direction; then, based on the generated set of spatial coordinates of the tea bud positions, the improved ant colony algorithm is used to obtain the overall optimal picking path of the operation area; then, according to the overall optimal picking path of the operation area, each tea bud on the optimal picking path in the current operation area is harvested.

6. The tea picking method using the tea picking device with redundant degree of freedom serial-parallel robotic arms according to claim 5, characterized in that: The process of obtaining the optimal picking path using the improved ant colony algorithm is as follows: (1) The operating area is divided into two low-density areas and a high-density area between the two low-density areas along the X-axis, and a transition area is also divided; the speed of the static platform in the low-density area except the transition area is , the velocity in the high-density area is , the speed in the transition region is ; (2) Set the pheromone on the path from node i to node j at the tth iteration Initial value, number of ants, pheromone weight , heuristic weight , volatility coefficient , speed influence coefficient , cross-interval penalty factor , pheromone increment adjustment coefficient , time window; (3) Defining and correcting heuristic information ;Calculate path selection probability; (4) Selection and , calculate the speed of the static platform when it is in the transition area, execute steps (2) and (3) to obtain the path selection probability of various paths from node i to node j; (5) Update the global pheromone. After each update of the global pheromone, recalculate the path selection probability of various paths from node i to node j; (6) When the number of iterations is reached, the path from node i to node j with the highest probability of path selection is selected as the path and The corresponding optimal picking path; (7) Repeat steps (4) to (6), and update and Until all and The combination of all the paths selected by the calculation is used to select the path from node i to node j with the largest probability as the final picking path from node i to node j, and the corresponding path of the final picking path is obtained. and combination; (8) The ant starts from the starting point of the operation area and moves to the node with the largest X-axis coordinate in the operation area. Every time it generates a path from node i to node j, it uses node j as the new node i, thereby generating the overall optimal picking path for the operation area.

7. The tea picking method using the tea picking device with redundant degree of freedom serial-parallel robotic arms according to claim 6, characterized in that: The heuristic information is Where, express The maximum value that can be obtained from the candidate set is the time difference between the ant's journey from node i to node j. , the time cost of ant q on the path from node i to node j , Represents the distance in the X-axis direction of the constant speed section of the path from node i to node j, and the speed of the static platform when it is in the constant speed section of the path from node i to node j , and They represent the starting X-axis coordinates and the ending X-axis coordinates of the speed change section in the path from node i to node j, and the speed of the static platform when it is in the speed change section in the path from node i to node j. , the total harvesting time of each node in the path from node i to node j , n is the total number of nodes in the path from node i to node j, is the harvesting time at node p, including picking and throwing time.

8. The tea picking method using the tea picking device with redundant degree of freedom serial-parallel robotic arms according to claim 7, characterized in that: The modified heuristic information is Where, is the speed difference weight, There are regional differences, and , express The minimum value that can be obtained from the candidate set.

9. The tea picking method using the tea picking device with redundant degree of freedom serial-parallel robotic arms according to claim 8, characterized in that: The path selection probability is Where, represents the set of unvisited nodes on the path from node i to node j; The updated global pheromone is Where, represents the pheromone increment left by ant q on the path from node i to node j, and , is the number of nodes successfully picked by ant q, is the time cost of ant q on the path from node i to node j, and the benchmark speed Take speed The maximum speed in the candidate set, represents the X-axis coordinate of node i, On behalf of the static platform The speed at which the 10. The tea picking method using the tea picking device with redundant degree of freedom serial-parallel robotic arms according to claim 6, characterized in that: The process of harvesting each tea bud on the overall optimal picking path in the current operation area according to the overall optimal picking path of the operation area is as follows: the translation device drives the static platform to drive the entire serial-parallel picking robot arm to translate along the X-axis direction, so that the two blade end midpoints of the picking end are translated in sequence to the X-axis coordinate positions of each tea bud position on the overall optimal picking path of the operation area, and the serial-parallel picking robot arm translates along the X-axis direction according to the corresponding speed calculated in step (7) on each final picking path; while the serial-parallel picking robot arm translates along the X-axis direction, the two joint motors drive the corresponding active arm to rotate, and each active arm drives the platform bracket and the picking end to move in a vertical plane parallel to the YOZ plane through the corresponding driven link group, so that the two blade end midpoints of the picking end are translated in sequence to the Y-axis coordinate positions of each tea bud position on the overall optimal picking path of the operation area, and the distance deviation between the two blade end midpoints of the picking end and the tea bud position in the X-axis direction and the Y-axis direction is calculated in real time. When the Y-axis direction When the distance deviation in the direction of the tea bud is not within the preset deviation range, the joint motor 2 drives the active arm 2 to rotate the driven link 2, and the driven link 2 drives the picking end to adjust along the X-axis direction through the dynamic platform bracket, so that the distance deviation in the X-axis direction is within the preset deviation range. If the distance deviation in the Y-axis direction is not within the preset deviation range, the two joint motors 1 drive the corresponding active arm 1 to rotate for adjustment; when the two blade ends of the picking end reach the tea bud position at the center point, the servo drives the servo arm to rotate forward, and the servo arm drives the lower ends of the two clamps to move toward each other through the two connecting rods, thereby driving the two blade ends to close and shear the tea buds; then the joint motor 3 drives the servo frame to drive the tea bud to rotate in the direction close to the belt conveyor mechanism, and the tea bud is thrown onto the conveyor belt of the belt conveyor mechanism by centrifugal force. The belt conveyor mechanism transports the tea bud to the material box; then the joint motor 3 drives the servo frame to drive the tea bud to rotate in the direction away from the belt conveyor mechanism to the original position, and at the same time the servo drives the servo arm to reverse, and the servo arm drives the two clamps and the two blades to move away from each other to the original position through the two connecting rods.

Images