Picking mechanical claw and robot

Abstract

The utility model provides a picking mechanical claw and a robot, and belongs to the technical field of picking robotics.The mechanical claw comprises a mounting plate, an upper cover plate, a movable plate, at least three clamping fingers and a bottom plate, and a plurality of supporting rods are connected between the top and the bottom of the upper cover plate and the mounting plate and between the top and the bottom of the upper cover plate and the bottom plate correspondingly; the movable plate is arranged on the supporting rod between the upper cover plate and the bottom plate in a sliding and sleeving manner; the top of the upper cover plate is connected with a driving device, the driving device is connected with a crank, the top of the movable plate is provided with a transmission rod, and the transmission rod penetrates through the upper cover plate and is connected with the crank; the clamping fingers are hinged to the bottom plate, and connecting rods are hinged between the movable plate and the clamping fingers; according to the mechanical gripper and the robot applying the mechanical gripper, the service life of a driving device can be prolonged, and objects can be stably clamped and prevented from being damaged by clamping.

Description

Technical Field

[0001] The utility model belongs to the technical field of picking robots, and in particular relates to a picking mechanical claw and a robot. Background Art

[0002] At present, automation technology has become more and more popular, especially in the application fields of industrial processing, logistics sorting and agricultural operations. Agricultural robot technology has become more and more perfect, with higher and higher working efficiency and wider working environment. Agricultural robots are robots that can automatically perform agricultural tasks. They are usually equipped with various sensors and actuators to help farmers complete tasks such as planting, spraying pesticides, and harvesting. Agricultural robots can improve production efficiency and reduce labor costs, while also reducing the use of chemical pesticides and fertilizers, thereby reducing environmental pollution. There are many types of agricultural robots, including self-driving tractors, plant protection drones, orchard picking robots, etc. These robots can automatically adjust their working modes according to the growth conditions and needs of crops to improve the yield and quality of crops.

[0003] The picking robot needs to use a mechanical claw. The Chinese utility model with the announcement number CN211729237U discloses a mechanical claw driven by a double crank slider mechanism, including an upper mounting plate, a middle translation plate and a lower fixed plate; the fixed guide rod passes through the upper end of the translation plate and is fixed to the mounting plate, and the lower end is fixed to the fixed plate; a motor is also provided on the fixed plate, and a crank is installed at the output end of the motor. The crank is connected to the bottom of the translation plate through a first transmission rod, so that the translation plate is driven by the motor to move up and down along the fixed guide rod; it also includes more than two finger assemblies, the inner side of the top of the finger assembly is hinged to the edge of the fixed plate, and the outer side is hinged to the edge of the translation plate through a second transmission rod, so that the mechanical claw is loosened or grasped as the translation plate moves up and down. The utility model has a simple structure, high control accuracy, and strong scalability, and can be easily serialized into two-finger, three-finger, four-finger and other mechanical claws.

[0004] Although the above-mentioned mechanical claw has a relatively simple structure and is easy to control, and can realize the grasping function, the translation plate of the mechanical claw will move up and down during the opening and closing process, and the driving motor is directly arranged in the same space as the translation plate. The translation plate will hit the motor during the up and down movement, and the driving motor is easily damaged by long-term use; in addition, the inner end face of its finger assembly is flat, which makes it difficult to grasp objects with curved surfaces, and it does not have anti-slip and buffering functions, so it is easy to damage it when grasping softer objects (such as fruits). Summary of the invention

[0005] The purpose of the utility model is to solve the problems mentioned in the background technology and to provide a picking mechanical claw and a robot, which can extend the service life of a driving device and stably clamp objects to avoid damaging the objects.

[0006] In order to achieve the above technical purpose, the technical solution adopted by the utility model is:

[0007] A picking mechanical claw comprises a mounting plate, an upper cover plate, a movable plate, at least three clamping fingers and a bottom plate, wherein the top and bottom of the upper cover plate are respectively connected to a plurality of support rods between the mounting plate and the bottom plate; the movable plate is slidably mounted on the support rods between the upper cover plate and the bottom plate; the top of the upper cover plate is connected to a driving device, the driving device is connected to a crank, and the crank is connected to the movable plate; the clamping fingers are hinged on the bottom plate, and a connecting rod is hinged between the movable plate and the clamping fingers.

[0008] Preferably, the driving device is a steering gear or a servo motor.

[0009] Preferably, the number of the clamping fingers is four and they are equidistantly distributed in a circular shape around the base plate.

[0010] Preferably, the upper cover plate is provided with a through hole matching the crank to allow the crank to rotate.

[0011] Preferably, the clamping fingers are in an inwardly curved shape, and the surfaces of the clamping fingers are covered with a flexible material.

[0012] A picking robot using any of the mechanical claws described above comprises a mobile cart, a balance platform, a mechanical arm and a mechanical claw, wherein the balance platform is arranged on the mobile cart, the mechanical arm is arranged on the balance platform, the mechanical claw is arranged at the end of the mechanical arm, and a camera is also arranged at the end of the mechanical arm.

[0013] Preferably, the chassis suspension of the mobile vehicle adopts an independent suspension.

[0014] Preferably, the robotic arm is a six-degree-of-freedom robotic arm.

[0015] Preferably, an L-shaped connecting plate is provided at the end of the robotic arm, the long plate of the connecting plate is perpendicular to the axis of the end of the robotic arm, the robotic claw is connected to the bottom of the long plate of the connecting plate, and the camera is connected to the outside of the short plate of the connecting plate.

[0016] Preferably, the camera is a binocular depth camera.

[0017] The beneficial effects of the utility model are:

[0018] 1. The mechanical claw provided in the present application has an upper cover plate added between the top mounting plate and the movable plate, and the driving device is arranged on the top of the upper cover plate to avoid direct contact between the driving device and the movable plate. In this way, during the opening and closing process of the mechanical claw, the movable plate is driven by the driving device and the crank to move up and down and will only contact the upper cover plate and the bottom plate, and will not hit the driving device, thereby avoiding damage to the driving device caused by impact and improving the service life of the mechanical claw.

[0019] 2. The clamping fingers of the mechanical claw provided in the present application are inwardly curved, so that the clamping fingers can better fit objects with curved surfaces (such as apples and other fruits). In addition, the surface of the clamping fingers is provided with flexible material, and the flexible material is in direct contact with the object during the grasping process, which can avoid the hard outer shell of the clamping fingers from clamping the object (especially soft objects such as fruits); therefore, the mechanical claw provided in the present application can not only better grasp objects with curved surfaces (the surface of most fruits is curved), but also avoid clamping the objects during the grasping process. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a structural diagram of the mechanical claw provided by this application;

[0021] Figure 2 is a top view of the mechanical claw provided by the present application;

[0022] Figure 3 It is the overall device structure diagram of the robot provided by this application;

[0023] Figure 4 is a front view of the overall device of the robot provided by the present application;

[0024] Figure 5 is a schematic diagram of a balance platform of a robot provided in this application;

[0025] Figure 6 It is a schematic diagram of the connection plate structure of the robot provided by this application;

[0026] Figure 7 It is a schematic diagram of the installation of the connecting plate, mechanical claw and visual camera of the robot provided by the present application;

[0027] Figure 8 is a system structure diagram of the robot provided by this application;

[0028] Fig. 9 It is an operation flow chart of the robot provided in this application.

[0029] Names of labels in the figure:

[0030] 1. Mounting plate, 2. Upper cover plate, 3. Movable plate, 4. Clamping finger, 5. Bottom plate, 6. Support rod, 7. Driving device, 8. Crank, 9. Connecting rod, 10. Transmission rod, 11. Balance table, 12. Robotic arm, 13. Camera, 14. Connecting plate, 15. Mobile trolley. DETAILED DESCRIPTION

[0031] The embodiments of the present invention are described in further detail below in conjunction with the accompanying drawings.

[0032] It should be noted that the terms such as "upper", "lower", "left", "right", "front", "back", etc. used in the utility model are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of the present utility model without substantially changing the technical content.

[0033] like Figure 1 and 2 As shown, the present application provides a picking mechanical claw, including a mounting plate 1, an upper cover plate 2, a movable plate 3, four clamping fingers 4 (at least three clamping fingers 4 are provided so as to stably clamp an object) and a base plate 5, wherein the top and bottom of the upper cover plate 2 are respectively connected to a plurality of support rods 6 between the mounting plate 1 and the base plate 5; the movable plate 3 is slidably mounted on the support rods 6 between the upper cover plate 2 and the base plate 5; the top of the upper cover plate 2 is connected to a driving device 7, and the driving device 7 is a steering gear or a servo motor.

[0034] A crank 8 is connected to the driving device 7, and a transmission rod 10 is provided on the top of the movable plate 3. The transmission rod 10 passes through the upper cover plate 2 and is connected to the crank 8. The upper cover plate 2 is provided with a through hole matching the transmission rod 10 to allow the crank 8 to swing with the transmission rod 10, that is, the through hole is a long through hole, and the transmission rod 10 is moved up and down by the crank 8 and is accompanied by left and right swings. The long through hole allows the transmission rod 10 to swing left and right.

[0035] The clamping fingers 4 are hinged on the base plate 5, and the clamping fingers 4 are distributed in a ring and equidistantly around the base plate 5; a connecting rod 9 is hinged between the movable plate 3 and the clamping fingers 4. The lifting and lowering of the movable plate 3 will drive the connecting rod 9 to rotate, and then drive the clamping fingers 4 to rotate, thereby completing the opening and closing of the mechanical claw to grasp and release the object.

[0036] The clamping fingers 4 are in an inwardly curved shape, which can better fit objects with curved surfaces (most fruits) and prevent the fruits from slipping out of the clamping fingers 4; the surfaces of the clamping fingers 4 are covered with flexible materials (materials such as silicone can be used), and the flexible material directly fits the objects to prevent the rigid surfaces of the clamping fingers 4 from pinching the objects, especially soft objects such as fruits.

[0037] The mechanical claw provided in the present application is based on the technology of the prior art. An upper cover plate is added between the top mounting plate and the movable plate, which can prevent the movable plate from directly hitting the drive device 7 during the lifting process and causing damage to the drive decoration 7, thereby increasing the service life of the mechanical claw. The clamping fingers 4 are arranged to be inwardly curved, which enables the mechanical claw to clamp objects more stably. The flexible material on the surface of the clamping fingers 4 can prevent the clamping fingers 4 from clamping objects.

[0038] like Figure 3-9As shown, the present application also provides a harvesting robot using the above-mentioned mechanical claw, including a mobile cart 15, a balance platform 11, a mechanical arm 12 and a mechanical claw, wherein the balance platform 11 is arranged on the mobile cart 15, the mechanical arm 12 is arranged on the balance platform 11, the mechanical claw is arranged at the end of the mechanical arm 12, and a camera 13 is also arranged at the end of the mechanical arm 12.

[0039] The mobile car 15 adopts four-wheel independent servo drive and double wishbone independent suspension, and can climb over 15cm obstacles and slopes. The chassis suspension structure is usually composed of shock absorbers, springs, cantilevers, tie rods, etc. Through the synergistic effect of these components, the vibration and bumps of the vehicle body can be reduced, and the stability and handling of the chassis can be improved. There are many types of chassis suspension structures, and the common ones include independent suspension, torsion beam suspension, multi-link suspension, etc. Among them, independent suspension is currently the most widely used structure, which enables the wheels to move independently, thereby better adapting to the unevenness of the road surface and improving the stability of the chassis.

[0040] The robotic arm 12 is a six-degree-of-freedom robotic arm, has greater flexibility and the ability to manipulate objects, can perform various complex actions, has higher accuracy and stability, and can achieve high-precision positioning and manipulation.

[0041] Different from the installation of traditional robotic arms, the present application provides a new balancing platform 11 between the robot robotic arm 12 and the mobile vehicle 15, so that no matter what terrain the chassis stops on, the base of the robotic arm can be kept parallel to the ground, thereby improving the stability and success rate of the robot's picking.

[0042] The balancing platform consists of a gyroscope sensor, three axes and an internal motor. Its core control device is an STM32 single-chip microcomputer. The gyroscope sensor placed on the top detects the platform deflection value and adjusts the PWM signal duty cycle according to the deflection angle to achieve the telescopic transformation of the three axes until the deviation signal of the gyroscope sensor disappears. The balancing platform is leveled so that the base of the robotic arm remains basically level with the ground.

[0043] An L-shaped connecting plate 14 is provided at the end of the robotic arm 12, the long plate of the connecting plate 14 is perpendicular to the axis of the end of the robotic arm 12, the robotic claw is connected to the bottom of the long plate of the connecting plate 14, and the camera 13 is connected to the outside of the short plate of the connecting plate 14; the camera 13 is a binocular depth camera.

[0044] The visual part uses a binocular depth camera to obtain scene depth information through two cameras, and obtains three-dimensional depth information in the scene by calculating the parallax between the two cameras. It can achieve accurate recognition and positioning of apples, so as to achieve precise grasping tasks.

[0045] Since the spatial coordinates obtained by the visual camera of the device are spatial coordinates based on the camera coordinate system, not the spatial coordinates in the robot coordinate system, they cannot be directly used as cruising target points and grasping target points. Therefore, the present invention adopts the Tais hand-eye calibration algorithm, obtains the conversion relationship between the camera coordinate system and the robot coordinate system through the hand-eye calibration algorithm, and converts the spatial coordinates obtained by the camera into the spatial coordinates in the robot coordinate system. The hand-eye calibration method includes the following steps (this article and Figure 8 and Fig. 9 The end effector in the figure refers to the mechanical claw):

[0046] Step 1: Install the end effector on the end of the collaborative robot through the adapter plate, and install the ASUS depth camera on the adapter plate. Place the calibration plate within the robot's motion range, adjust the robotic arm to complete the shooting task at 10 different viewing angles, and record the robotic arm posture information corresponding to each viewing angle.

[0047] Step 2: Use MATLAB to complete camera calibration and hand-eye calibration. Camera calibration is completed using the Camera Calibrator in the MATLAB built-in library, and then the hand-eye calibration program is run to obtain the transformation matrix. The Tsai calculation method is as follows:

[0048] Known transformation matrix from the end of the robot to the camera coordinate system Transformation matrix from calibration plate coordinate system to camera coordinate system Transformation matrix from the robot base coordinate system to the calibration plate coordinate system And the transformation matrix from the robot end coordinate system to the robot base coordinate system The following relationship exists:

[0049]

[0050] in:

[0051] Can be solved directly from the captured image of the calibration plate

[0052] It can be obtained from the end-of-arm pose parameters

[0053] Since the calibration plate is fixed in position, it is an unknown quantity for each set of images.

[0054] By transforming formula (1), we can get:

[0055]

[0056] Combining 10 sets of calibration data, we can get the calculation equations:

[0057] ......

[0058]

[0059] Order The coefficient matrix on the left is A, and the coefficient matrix on the right is B. Since A, B, and X are all transformation matrices,

[0060]

[0061]

[0062] AX=XB can be decomposed into the following equation:

[0063] R A R X =R X R B

[0064] (R X -1)T X =R X T B -T A

[0065] The transformation matrix from the end of the robot arm to the camera coordinate system can be obtained by solving it.

[0066] Step 3: Let the spatial coordinate in the camera coordinate system be P camera , the spatial coordinate in the robot base coordinate system is P robot , the transformation matrix is

[0067]

[0068] The spatial coordinates of the robot base coordinate system can be calculated by formula (2) to facilitate the robot to complete motion control and grasping tasks.

[0069] The picking robot obtains the grasping target based on visual recognition, so it needs to perform data set training and hand-eye calibration before use. The grasping task can be performed only after the target recognition and coordinate conversion are achieved. The operation method includes the following steps:

[0070] Step 1: Before use, use YOLOv5 deep learning to train the data set, select the recognition targets in the picture set and classify them. Return the spatial coordinate system of the grasped target to achieve chassis navigation and robotic arm grasping.

[0071] Step 2: Use a high-speed calibration plate, keep the calibration plate in place, adjust the robot arm posture, read RBG images at 10 different postures, and record the spatial posture information of the robot arm. After camera calibration, use the Tais hand-eye calibration algorithm to calculate the transformation relationship between the camera coordinate system and the robot arm base coordinate system, and convert the target space coordinates obtained by the camera to the space coordinates under the robot arm base coordinate system.

[0072] Step 3: Build a map and plan the target path in the host computer, send speed commands to the middle layer STM32f103 microcontroller through serial communication, and finally send instructions to the chassis through CAN communication to complete the control of the chassis four-wheel differential drive. Move to the vicinity of the target fruit to ensure that the grasping target is within the movement space of the robot arm.

[0073] Step 4: Keep the host computer connected to the robot's WIFI network, run the WIFI communication node, start the Moveit control interface, and run the Python file that controls the end of the robot to move to the specified position so that the end effector can perform the grasping action.

[0074] Step 5: After the motion control of the robotic arm is completed, a grab command is sent to the middle-level STM32f103 microcontroller through serial communication. The microcontroller controls the MG996R servo to grab the fruit. After completion, a success signal is transmitted to the host computer, and the host computer controls the robotic arm to return to the initial position to complete the grabbing process.

[0075] It should be noted that the innovation of the present application lies in the mechanical claw, and the picking robot only uses the mechanical claw. The above-mentioned description of the robot's target recognition process and the principle of the grasping task are only specific embodiments of a robot that can be adopted, but are not limited to this robot. That is, any intelligent robot that uses the mechanical claw provided by this application is the object that this application wants to protect. The protection object of this application does not involve improvements in program control, but lies in the mechanical claw and the robot using the mechanical claw, which are the protection objects of the utility model.

[0076] The above are only preferred implementations of the utility model. The protection scope of the utility model is not limited to the above embodiments. All technical solutions under the idea of ​​the utility model belong to the protection scope of the utility model. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the utility model.

Claims

1. A picking mechanical claw, characterized in that: The invention comprises a mounting plate (1), an upper cover plate (2), a movable plate (3), at least three clamping fingers (4) and a bottom plate (5); the top and bottom of the upper cover plate (2) are respectively connected to a plurality of support rods (6) between the mounting plate (1) and the bottom plate (5); the movable plate (3) is slidably mounted on the support rods (6) between the upper cover plate (2) and the bottom plate (5); the top of the upper cover plate (2) is connected to a driving device (7), the driving device (7) is connected to a crank (8), the top of the movable plate (3) is provided with a transmission rod (10), the transmission rod (10) passes through the upper cover plate (2) and is connected to the crank (8); the clamping fingers (4) are hinged to the bottom plate (5), and a connecting rod (9) is hinged between the movable plate (3) and the clamping fingers (4).

2. A picking mechanical claw according to claim 1, characterized in that: The driving device (7) is a steering gear or a servo motor.

3. The picking mechanical claw according to claim 1, characterized in that: There are four clamping fingers (4) which are equidistantly distributed in a circular shape around the bottom plate (5).

4. The picking mechanical claw according to claim 1, characterized in that: The upper cover plate (2) is provided with a through hole matching the transmission rod (10) and allowing the crank (8) to swing with the transmission rod (10).

5. The picking mechanical claw according to claim 1, characterized in that: The clamping finger (4) is in the shape of an inwardly curved arc, and the surface of the clamping finger (4) is covered with a flexible material.

6. A harvesting robot using the mechanical claw according to any one of claims 1 to 5, characterized in that: The invention comprises a mobile vehicle (15), a balancing platform (11), a mechanical arm (12) and a mechanical claw, wherein the balancing platform (11) is arranged on the mobile vehicle (15), the mechanical arm (12) is arranged on the balancing platform (11), the mechanical claw is arranged at the end of the mechanical arm (12), and a camera (13) is also arranged at the end of the mechanical arm (12).

7. A picking robot according to claim 6, characterized in that: The chassis suspension of the mobile vehicle (15) adopts an independent suspension.

8. The picking robot according to claim 6, characterized in that: The mechanical arm (12) is a six-degree-of-freedom mechanical arm.

9. The picking robot according to claim 6, characterized in that: An L-shaped connecting plate (14) is provided at the end of the mechanical arm (12); the long plate of the connecting plate (14) is perpendicular to the axis of the end of the mechanical arm (12); the mechanical claw is connected to the bottom of the long plate of the connecting plate (14); and the camera (13) is connected to the outside of the short plate of the connecting plate (14).

10. The picking robot according to claim 6, characterized in that: The camera (13) is a binocular depth camera.

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