CN116619342A - Robot and pick-up manipulation method for robot - Google Patents

Abstract

The application discloses a robot and a pick-up manipulation method for the robot. The robot includes a robot body and a pickup device having first and second finger mechanisms, each finger mechanism being a five-bar mechanism having two degrees of freedom and capable of being directly drive actuated, the method comprising: enabling the robot main body to drive the pick-up device to be close to an object to be picked up, enabling the distal ends of the finger parts of the first finger mechanism to touch a supporting surface near one side of the object to be picked up, and enabling the distal ends of the finger parts of the second finger mechanism to touch and press the top surface near the other side of the object; the first finger mechanism is driven toward the second finger mechanism such that the fingers of the first finger mechanism scoop under the object and the object rotates about its point of contact with the second finger mechanism, thereby causing the object to be gripped by the fingers of the first and second finger mechanisms. With this method, a sheet lying on the support surface can be picked up reliably and quickly.

Description

Robot and pick-up manipulation method for robot

Technical Field

The present application relates to a robot having a pickup function and a pickup manipulation method thereof.

Background

With the development of robotics, various robots having a pickup function or pickup devices for robots have been developed. For example, U.S. patent No. 8973958B2 discloses a gripping device useful for gripping an object, the gripping device comprising underactuated (un-actuated) mechanical fingers having two degrees of freedom, each configured as a five-bar linkage with one actuation joint. However, such gripping devices are only suitable for picking up objects having a certain thickness, and it is difficult to pick up thin sheets (e.g. thin plastic cards on a table top). For a sheet, a robot arm having a suction cup or suction cup group is commonly used for pickup, however, since the suction capacity of the suction cup depends on the condition of the contact surface, the versatility of such a pickup device is not good.

Disclosure of Invention

The present application has been made to solve at least some of the above-mentioned problems, and provides a robot and a pick-up manipulation method for the robot.

The "summary" corresponds to the content of the claims to provide literal support for the claims, which are added after confirming the claim content.

With the pick-up manipulation method provided by the application, an object can be reliably picked up in a shovel-behind-the-clamp (pin), especially suitable for picking up a sheet lying on a supporting surface, and the pick-up manipulation can be adapted to complex constraints imposed by a hard supporting surface in contact with the object, and high-speed pick-up can be achieved because the two finger mechanisms are directly driven and actuated.

Drawings

FIG. 1 (a) shows a schematic view of a robotic arm having a pick-up device according to an embodiment of the application;

FIG. 1 (b) shows a schematic view of a quad-rotor aircraft with a pickup device according to an embodiment of the present application;

fig. 2 shows an exploded view of a pickup device according to an embodiment of the present application.

Fig. 3 shows a pick-up manipulation method according to an embodiment of the present application in steps.

Fig. 4 shows the parameter variation when implementing the pick-up manipulation method according to an embodiment of the present application.

Fig. 5 shows a pick-up manipulation method according to another embodiment of the present application in steps.

Fig. 6 shows a pick-up manipulation method according to a further embodiment of the present application in steps.

Detailed Description

In order to better understand the technical solution of the present application, the following describes in detail the pickup manipulation method for a robot provided by the present application with reference to the accompanying drawings. It should be noted that the features of the embodiments, implementations and examples of the present application may be combined with each other arbitrarily without conflict. Moreover, those skilled in the art will appreciate that the following discussion is intended to be merely illustrative of exemplary embodiments, and is not intended to be limiting of the broader aspects of the present disclosure, which are embodied in the exemplary constructions. In the description of the present application, the terms "first," "second," and the like are used merely to distinguish between descriptions and should not be construed as indicating or implying a relative importance or order.

In the present application, a robot is broadly contemplated to have a pickup device (e.g., a manipulator) and be able to perform an intended action in accordance with a built-in program, or any machine that determines a target and performs an intended action based on artificial intelligence, including but not limited to an aircraft having a pickup device (e.g., a quad-rotor aircraft), an industrial or civilian robotic arm having a pickup device, a robot having the robotic arm, and the like. Wherein the pick-up device is adapted to pick up objects placed on a support surface, in particular sheets lying on a rigid support plane (or so-called flats, i.e. objects having a smaller thickness compared to the length and/or width, such as but not limited to thin plastic cards, bank cards, books, cell phones, etc.).

Fig. 1 (a) shows an automatic mechanical arm with a pickup device according to an embodiment of the present application, and fig. 1 (b) shows a quad-rotor aircraft with a pickup device according to an embodiment of the present application. The pick-up device 1 as a whole is movable with the movement of a robot body (e.g. a robotic arm or a quadrotor body) 2 attached thereto, for example, up-down with respect to a horizontal plane, tilting (as shown in fig. 1 (a)), rotating about a vertical axis, etc. In some embodiments, the robot body may be part of a pick-up device.

As shown in fig. 1 (a) and 1 (b), each pickup device 1 is a two-finger pickup device having two finger mechanisms 10, 10'. The two finger mechanisms 10,10' of each pick-up device may have a similar construction, wherein each finger mechanism is a five-bar linkage (five-bar linkage) with two degrees of freedom (DOF) and capable of being directly driven and actuated.

Taking the finger mechanism 10 as an example, as shown in fig. 2, the finger mechanism 10 may specifically include: a first motor 11 and a second motor 21, each of which is independently controlled to rotate; a first proximal link 12 and a second proximal link 22, which are respectively fixed to the first motor 11 and the second motor 21, such that the first proximal link 12 can be rotated by the first motor 11 and the second proximal link 22 can be rotated by the second motor 21; the proximal ends of the first distal link 13 and the second distal link 23 are pivotally connected to the distal end of the first proximal link 12 and the distal end of the second proximal link 22 by a first pivot 14 and a second pivot 24, respectively, and the distal end of the second distal link 23 is pivotally connected to the middle of the first distal link 13 by a third pivot 15. Thus, the first proximal link 12, the second proximal link 22, the first distal link 13, and the second distal link 23 constitute a two-degree-of-freedom finger link mechanism, which is directly driven by the first motor 11, the second motor 21, and constitutes a five-link mechanism with the first motor 11, the second motor 21.

Alternatively, the first motor 11 and the second motor 21 are electromagnetic motors. Alternatively, the first motor 11 and the second motor 21 are brushless universal joint motors. The first motor 11 and the second motor 21 are opposed to each other and rotatable about a common or parallel axis to each other. The first motor 11 and the second motor 21 may be spaced apart from each other. The first and second proximal links 12, 22 may be connected to screw holes 26, 27 on the opposite surfaces of the first and second motors 11, 21, respectively, by two screws (not shown). The screw holes 26, 27 corresponding to each proximal link may be centrally symmetrical with respect to the axis of the corresponding motor.

The distal end of the first distal link 13 is provided with a finger 16. The distal ends of the fingers 16 are also distal ends of the corresponding finger mechanisms. To facilitate insertion between the object to be picked and the support surface, at least the distal end portion of the finger 16 has a wedge shape or spade shape. In the case of a wedge shape, when the finger 16 is taken in a plane perpendicular to the axis of the first motor 11, the distal end of the cross section of the finger 16 is a wedge shape having a sharp corner. The angle of the sharp corner (i.e., the angle between the top surface 161 and the bottom surface 162 of the finger 16) may be in the range of 5 ° to 30 °, and preferably in the range of 10 ° to 15 °. Further, the finger 16 may be formed as part of the first distal link 13 or may be removably attached to the distal end of the first distal link 13. The bottom surface 162 of the finger 16 may extend in the same direction as the distal end 132 of the first distal link 23, but at an obtuse angle to the direction of extension of the proximal end 131 of the first distal link 23. The obtuse angle may be in the range of 120 ° to 180 °, preferably in the range of 140 ° to 160 °.

Returning to fig. 1 (a) or 1 (b), the two finger mechanisms 10,10' of each pick-up device may be connected to each other by a frame 30. The two ends of the frame 30 are respectively fixed with a pair of motors, and the two pairs of motors are spaced at a proper distance relative to each other, so that on one hand, stable clamping of an object to be picked up (particularly a sheet-like object) can be ensured, and on the other hand, interference between connecting rods is not easy to occur in the processes of picking up and clamping. Furthermore, the bottom surfaces of the fingers of the two finger mechanisms 10,10' of each pickup device may be opposed to each other, in other words, the bottom surfaces of the fingers may serve as gripping surfaces for gripping an object.

Optionally, a sensor system (not shown) is also provided on the robot body and/or on the pick-up device. The sensor system includes sensors capable of detecting the presence, shape, location, support surface information of an object to be picked up, such as, but not limited to, visual sensors, photoelectric sensors, ultrasonic sensors, and the like. Alternatively, such a sensor system may be provided outside the robot and in communication with the robot, or the object to be picked up may itself report its own information of shape, position, etc. to the robot.

Further, a controller (not shown) is provided in the robot body and/or in the pick-up device, the controller obtaining detection information from the sensor system, the pick-up operation being controlled by controlling the movement of the robot body and the rotation of the respective pair of motors of the two finger mechanisms 10, 10'.

Accordingly, the controller may include a memory storing a program that, when executed by the processor, performs a pickup manipulation method according to an embodiment of the present application.

Next, a pickup manipulation method for a robot according to an embodiment of the present application will be described with reference to fig. 3. It should be noted that, numbers 1 to 8 in fig. 3 represent serial numbers of steps sequentially performed in this embodiment. Further, the pickup device in this embodiment is the pickup device described with reference to fig. 1 (a) and 2, but the present application is obviously not limited thereto.

Step 1: an object 40 to be picked up (hereinafter, simply referred to as an object) lying on the support surface 50 is detected using a sensor system.

Step 2: the robot arm (robot body) 30 moves the pickup device from above (including obliquely above) toward the object 40. Alternatively, during this time, the entire pick-up device may be tilted with respect to the support surface 50 supporting the object 40.

Step 3: when the pick-up device is positioned substantially above the object 40, the pick-up device is oriented such that the bottom surface of the finger (also referred to as the thumb) of the first finger 10 of the two finger mechanisms 10,10' forms a predetermined angle of attack with the support surface 50 at which the object 40 is positioned. The angle of attack is between 0 deg. and 90 deg., preferably between 30 deg. and 50 deg.. The pick-up device is then lowered by the robotic arm 30 until the distal ends (i.e., tips) of the fingers of the first finger mechanism 10 touch the support surface 50 near one side of the object 40. In this process, it may not be necessary to detect the distance of the distal end of the finger from the support surface 50 in real time, but rather the touch may be detected by a sensor measuring the displacement of the finger mechanism, which is compliantly controlled with a low proportional/differential gain. When such a touch is detected, the robot arm 30 is accelerated upward so that it stops descending rapidly, so as not to hit the support surface 50 drastically.

Simultaneously or subsequently to the distal ends of the fingers of the first finger mechanism 10 touching the support surface 50 near one side of the object 40, the distal ends of the fingers of the second finger mechanism 10' (also referred to as index fingers) touching the top surface of the object near the other side of the object 40.

Step 4: the first finger 10 is driven with a high proportional/differential gain towards the second finger 10' so that the pick-up device is moved towards the closed position. In the process, the distal ends of the fingers of the second finger mechanism 10' are pressed down against the top surface of the object so that the fingers of the first finger mechanism 10 scoop under the object 40 and the object 40 is scooped up by the fingers of the first finger mechanism 10. This process causes the stiffness (i.e., control gain) of the finger mechanism 10,10' to become greater.

Step 5: the second finger 10' is moved further towards the first finger 10. As the fingers of the first finger mechanism 10 continue to scoop under the object 40, the object 40 rotates about its point of contact with the fingers of the second finger mechanism 10' and enters the workspace formed by the first and second finger mechanisms. At the same time, the stiffness of the finger 10,10' continues to increase.

In step 6, finally, the object 40 is reliably held by the fingers of the first finger mechanism 10 and the fingers of the second finger mechanism 10', and the robot arm 30 starts to drive the pickup device to move upward. At the same time, the rigidity of the finger mechanism 10,10' is kept large in order to ensure gripping.

Step 7, the pick-up device has moved away from the support surface with the upward movement of the robotic arm 30.

Step 8, the pick-up operation is completed and the object 40 continues to be transported.

In the present embodiment, by adopting the post-scooping gripping manner, a sheet lying on the supporting surface can be reliably picked up, and this pickup manipulation can be adapted to complex constraints imposed by a hard supporting surface in contact with an object, and since the two finger mechanisms are directly driven to actuate (rather than under-drive), high-speed pickup is achieved.

Fig. 4 shows in a parametric diagram how a pick-up device mounted on a robot arm is controlled during a pick-up maneuver. The dashed line in fig. 4 represents the instruction value of the parameter, and the solid line represents the actual value of the parameter. The control task is formulated as impedance control (impedance control): the pick-up device follows the reference motion trajectory while properly adjusting the control gain (see the curves for motor joint angle and finger stiffness in fig. 4). As can be seen from the motor joint angle curves, in step 4 and step 5, the four motors of each pick-up are actively controlled by the controller (rather than under-actuated). Thus, the robotic arm need not stay long (see fig. 4 for a plot of z-position (i.e., height position) and z-velocity of the arm). The average cycle time from the above-described step 3 to step 6 is only 0.35 seconds, thereby achieving high-speed pickup (scooping) of the sheet.

Figure 5 illustrates a pickup steering method for a quad-rotor aircraft in accordance with another embodiment of the present application. In addition to replacing the robotic arm with a quad-rotor vehicle body, this embodiment also differs from the embodiment of fig. 3 in that, as shown in step 3 of fig. 5, the fingers of the second finger may then touch the support surface 50 near one side of the object 40 after the fingers of the first finger touch the top surface of the object 40 (by tilting the quad-rotor vehicle body further).

Figure 6 illustrates a pickup steering method for a quad-rotor aircraft in accordance with yet another embodiment of the present application. The quad-rotor aircraft in this embodiment has an added mechanism for driving the pickup to tilt as compared to the quad-rotor aircraft in the embodiment of fig. 5. Thus, the pickup device can be tilted to the predetermined tilt angle β with the aircraft body kept horizontal.

Further, by simply reversing the pick-up manipulation method in the above-described embodiment, a placing operation of rapidly placing the sheet on the supporting surface can be achieved. The detailed steps are not repeated.

It is to be understood that the embodiments and examples described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims. The application is not limited to the specific steps, parameters, and materials disclosed herein. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. The scope of the application is limited only by the appended claims.

Claims (15)

1. A pickup manipulation method for a robot including a robot body and a pickup device attached to the robot body, the pickup device having a first finger mechanism and a second finger mechanism, each of the first and second finger mechanisms being a five-bar mechanism having two degrees of freedom and being directly drive-actuatable, and each of the finger mechanisms including a finger portion having a distal end portion in a wedge shape or a spade shape, the pickup manipulation method comprising:

the robot main body drives the pickup device to move from the upper side towards an object to be picked, which is laid on the supporting surface;

with the pick-up device oriented such that the bottom surface of the first finger forms a predetermined angle of attack with the support surface, causing the robot body to move the pick-up device downward such that the distal ends of the first finger touch the support surface near one side of the object and the distal ends of the second finger touch the top surface near the other side of the object;

with the distal ends of the fingers of the second finger mechanism pressing against the top surface near the other side of the object, driving the first finger mechanism to move toward the second finger mechanism such that the fingers of the first finger mechanism scoop under the object and the object rotates about its point of contact with the fingers of the second finger mechanism;

when the object is clamped by the finger parts of the first finger mechanism and the second finger mechanism, the robot main body drives the pick-up device to leave the supporting surface.

2. The pick-up manipulation method of claim 1, further comprising: the object to be picked up lying on the support surface is detected using a sensor system.

3. The pickup manipulation method according to claim 1, wherein a touch of the finger of the first finger on the support surface is detected by measuring a displacement of the first finger in a process of causing the robot body to move the pickup device downward.

4. A pick-up manipulation method according to claim 3, wherein the robot body is accelerated upward when a touch of the finger of the first finger mechanism against the support surface is detected.

5. The pickup manipulation method according to claim 1, wherein control of the pickup device in the pickup manipulation method is formulated as gain-adjustable impedance control.

6. The pickup manipulation method according to claim 1, wherein in driving the first finger toward the second finger, a gain larger than a gain in driving the pickup device downward by the robot body is used for control, the gain being a proportional gain or a differential gain.

7. The pickup manipulation method according to claim 1, wherein rigidity of the first finger mechanism and the second finger mechanism increases, respectively, in driving the first finger mechanism to move toward the second finger mechanism.

8. The pick-up manipulation method of claim 1, wherein the predetermined angle of attack is between 30 ° and 50 °.

9. The pickup manipulation method according to any one of claims 1 to 8, wherein each of the first finger mechanism and the second finger mechanism includes:

a first motor and a second motor, which are independently controlled to rotate, respectively;

a first proximal link and a second proximal link, which are respectively fixed with the first motor and the second motor, so as to be respectively driven to rotate by the first motor and the second motor;

a first distal link and a second distal link, the proximal ends of which are pivotally connected to the distal ends of the first proximal link and the second proximal link, respectively, the distal end of the second distal link being pivotally connected to the middle of the first distal link; and

the finger is disposed distally of the first distal link.

10. The pickup operation method according to claim 9, wherein in each of the first finger mechanism and the second finger mechanism, the first motor and the second motor are opposed to each other, and the first motor and the second motor are rotatable about a common or mutually parallel axis.

11. The pickup manipulation method according to claim 9, wherein the first motor and the second motor of each of the first finger mechanism and the second finger mechanism are actively controlled in accordance with a predetermined program in driving the first finger mechanism to move toward the second finger mechanism.

12. The pick-up manipulation method according to any one of claims 1 to 8, wherein the object is a sheet.

13. The pick-up manipulation method according to any one of claims 1 to 8, wherein the robot is an aircraft or an automated mechanical arm having the pick-up device.

14. A robot comprising a controller comprising a processor and a memory, the memory storing a program that, when executed by the processor, performs the pick-up manipulation method according to any one of claims 1 to 13.

15. The robot of claim 14, wherein the controller is configured to control lifting and tilting of the robot body and to individually control the first motor and the second motor of each of the first finger mechanism and the second finger mechanism.