An anti-symmetrical spatial parallel robot for pick-and-place operations and a working method thereof

Abstract

This invention discloses an antisymmetric parallel robot for pick-and-place operations and its working method. In this invention, one end of the active link one is hinged to the middle of a fixed shaft, and the other end of the active link one is hinged to the middle of a hinge shaft one. One end of the driven link one and driven link two are respectively hinged to both ends of hinge shaft one, and the other end is respectively hinged to both ends of hinge shaft two. One end of each of the two drive shafts is respectively hinged to both ends of the fixed shaft, and the other end is respectively hinged to connecting shaft one and connecting shaft two. One end of the active link two and active link three are respectively fixed to connecting shaft one and connecting shaft two, and the other end is respectively hinged to both ends of hinge shaft three. Both ends of the driven link three are respectively hinged to the middle portions of hinge shaft two and hinge shaft three. This invention proposes a novel parallel robot configuration that arranges two branches with spatial degrees of freedom antisymmetrically, enabling three-degree-of-freedom translational motion at the end effector.

Description

Technical Field

[0001] This invention belongs to the field of industrial machinery design technology, specifically relating to an antisymmetric parallel robot for pick-and-place operations and its working method. Background Technology

[0002] In industrial production, it is often necessary to move products from one location to another for sorting, handling, or packaging purposes. This operation is widely used in industries such as photovoltaics, pharmaceuticals, consumer goods, food, electronics, and automobiles. Modern production often employs automated equipment such as robots to achieve this operation, thereby improving production efficiency and reducing production costs. With the increasing market demand for product diversity and production flexibility, traditional serial robots are no longer sufficient to meet the needs of efficient, precise, and reliable production. Parallel robots, due to their unique structure, fast response speed, and high positioning accuracy, have become the ideal choice for high-speed industrial pick-and-place operations.

[0003] Parallel robots connect the load and base in parallel via multiple arms and actuators. Unlike the single-chain structure of traditional serial robots, their unique mechanical structure gives them significant advantages in acceleration, stability, and load capacity. In particular, the Delta parallel robot, proposed by Professor Reymond Clavel of Switzerland in the early 1980s, quickly became a typical representative of commercial parallel robots, possessing unparalleled advantages in high-speed pick-and-place operations.

[0004] Currently, parallel robot products in the market are still dominated by Delta and its improved versions. Delta parallel robots have multi-branch characteristics and closed-loop motion characteristics. On the one hand, this results in high load and high stiffness performance advantages, but on the other hand, it also leads to disadvantages such as large space footprint and complex kinematics and dynamics. Compared with the increasingly popular SCARA and serial robots with their single-branch "slender" shape, Delta and other parallel robots have a "short and stout" shape envelope characteristic. In practical applications, they must be reasonably arranged to avoid collisions or interference with the environment, which obviously contradicts the pursuit of compact layout in the limited space of industrial scenarios. Secondly, the closed-loop motion characteristics limit the workspace and also make the movement of passive joints impossible to control directly. Its kinematics and dynamics have strong nonlinear coupling, which further increases the difficulty of algorithm development. Therefore, the configuration of traditional parallel robots such as Delta cannot meet the application requirements of compactness, flexibility and ease of use in industrial scenarios, which is the main factor restricting their product promotion. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and to propose an antisymmetric parallel robot for pick-and-place operations and its working method.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention discloses an anti-symmetric parallel robot for pick-and-place operations, comprising a base, a first branch, a second branch, and a drive assembly. The first branch includes an active link, a hinge shaft, a driven link, a driven link, and a second hinge shaft; the second branch includes a drive shaft, a drive shaft, a connecting shaft, a second connecting shaft, an active link, an active link, a hinge shaft, and a driven link; the drive assembly includes a first drive motor, a second drive motor, a third drive motor, a spur gear pair, a bevel gear pair, and a bevel gear pair.

[0008] A fixed shaft is fixed on the base; one end of the active connecting rod perpendicular to the fixed shaft is hinged to the middle of the fixed shaft and driven by a drive motor mounted on the base via a spur gear pair, with the output shaft of the drive motor parallel to the fixed shaft; the other end of the active connecting rod is hinged to the middle of a hinge shaft, and both ends of the hinge shaft are respectively hinged to one end of a driven connecting rod and a driven connecting rod, with the driven connecting rod parallel to the driven connecting rod; the other ends of the driven connecting rod and the driven connecting rod are respectively hinged to both ends of the hinge shaft; drive shafts one and two are symmetrically arranged on both sides of the active connecting rod and coaxially arranged with the fixed shaft, and drive shafts one and two are close to the active connecting rod. One end of rod one forms a revolute joint with both ends of the fixed shaft; the connecting shaft one and connecting shaft two, which are parallel to and perpendicular to the fixed shaft, form a revolute joint with the ends of drive shaft one and drive shaft two away from the active connecting rod one, and are driven by drive motor two and drive motor three, which are mounted on the base, through bevel gear pair one and bevel gear pair two, respectively, and the output shafts of drive motor two and drive motor three are coaxial with the fixed shaft; one end of the parallel active connecting rod two and active connecting rod three is fixed to connecting shaft one and connecting shaft two, respectively, and the other end is hinged to both ends of hinge shaft three; the two ends of the driven connecting rod three, which is parallel to the active connecting rod one, are hinged to the middle parts of hinge shaft three and hinge shaft two, respectively.

[0009] In this configuration, the transmission ratios of bevel gear pair 1 and bevel gear pair 2 are equal; the fixed shaft, hinge shaft 1, hinge shaft 2, drive shaft 1, drive shaft 2, and hinge shaft 3 are arranged in parallel; let rod A be an assembly composed of the fixed shaft, drive shaft 1, drive shaft 2, connecting shaft 1, and connecting shaft 2; rod B be the second driving link; rod C be the third driving link; rod D be the third hinge shaft; rod E be the first hinge shaft; rod F be the first driven link; rod G be the second driven link; rod H be the second hinge shaft; and rod I be the first driving link. J is the driven link three. Virtual link K is the line connecting the hinge center of the driving link one and the hinge axis one to the hinge center of the driven link three and the hinge axis two. Virtual link L is the line connecting the hinge center of the driving link one and the fixed axis to the hinge center of the driven link three and the hinge axis three. Links A, B, C and D constitute parallelogram mechanism one. Links E, F, G and H constitute parallelogram mechanism two. Virtual links L, I, J and K constitute parallelogram mechanism three with virtual links.

[0010] Preferably, the spur gear pair includes a driving spur gear and a driven spur gear. The driven spur gear forms a rotating pair with the connecting shaft and is fixed to the driving connecting rod. The driving spur gear forms a rotating pair with the base and meshes with the driven spur gear, and is driven by a drive motor.

[0011] Preferably, the first bevel gear pair includes a first driving bevel gear and a first driven bevel gear. The first driven bevel gear is fixed on the first connecting shaft. The first driving bevel gear and the base form a rotating pair and mesh with the first driven bevel gear, and are driven by the second drive motor.

[0012] Preferably, the second bevel gear pair includes a second driving bevel gear and a second driven bevel gear. The second driven bevel gear is fixed on the second connecting shaft. The second driving bevel gear and the base form a rotating pair and mesh with the second driven bevel gear, and are driven by the third drive motor.

[0013] The present invention discloses a working method for an antisymmetric spatial parallel robot used for pick-and-place operations, as detailed below:

[0014] The base is installed on the mounting column next to the conveyor mechanism, with the fixed shaft, hinge shaft one, drive shaft one, and drive shaft two all in a vertical position. Drive motor two is positioned above drive motor three, and the pick-and-place actuator is coaxially mounted on the lower end of hinge shaft two. In the initial state, the pick-and-place actuator is located directly above the work platform next to the conveyor mechanism, and driven linkage one, driven linkage two, driving linkage two, and driving linkage three are all in a horizontal position. When the conveyor mechanism transports the item to the target position on the conveyor mechanism and stops, the controller controls drive motor one, drive motor two, and drive motor three to cooperate. Through parallelogram mechanism one, parallelogram mechanism two, and parallelogram mechanism three, hinge shaft two drives the pick-and-place actuator to translate and lift, completing the operations of picking up the item from the conveyor mechanism, translating the item, and placing the item on the work platform. The pick-and-place actuator driven by hinge shaft two will not deflect relative to the horizontal plane during translation and lifting.

[0015] When the output shaft of drive motor one rotates forward or backward, drive motor one drives drive linkage one through spur gear pair to drive hinge shaft one to rotate in reverse or forward around the central axis of fixed shaft. Then driven linkage one, driven linkage two, hinge shaft two and driven linkage three rotate around the corresponding rotation center axis and translate on the horizontal plane, thereby driving the pick-and-place actuator to translate on the horizontal plane.

[0016] In parallelogram mechanism one, the driving links two and three remain parallel throughout their motion. Similarly, the driven bevel gears one and two, which have fixed relationships with the driving links two and three respectively, also move synchronously. Therefore, bevel gears one and two form a bevel gear differential transmission mechanism. The driving bevel gears one and two are driven by drive motors two and three respectively. In this bevel gear differential transmission mechanism, the driven bevel gears one and two have both rotations around the central axes of connecting shaft one and connecting shaft two, and revolutions around the central axis of a fixed shaft, thus giving parallelogram mechanism one two degrees of freedom of motion.

[0017] When the rotation angle of drive motor 2 is 'a' and the rotation angle of drive motor 3 is 'b', driven bevel gear 1 drives drive link 2 and drive shaft 1 to rotate around the fixed axis via connecting shaft 1. Driven bevel gear 2 drives drive link 3 and drive shaft 2 to rotate around the fixed axis via connecting shaft 2, thus causing the parallelogram mechanism 1 as a whole to revolve around the central axis of the fixed axis with a rotation angle of (a+b) / 2. Driven bevel gear 1 drives drive link 2 to rotate around the central axis of connecting shaft 1 via connecting shaft 1. Driven bevel gear 2 drives drive link 3 to rotate around the central axis of connecting shaft 2 via connecting shaft 2. The rotation angles of drive link 2 and drive link 3 around connecting shaft 1 and connecting shaft 2 are both (ba) / 2. Therefore, when the speed, rotation angle, and direction of drive motor 2 and drive motor 3 are the same, connecting shaft 1... The connecting shaft 2 is stationary relative to the drive shaft 1 and drive shaft 2 respectively. The parallelogram mechanism 1 rotates around the central axis of the fixed shaft, and drives the parallelogram mechanism 1 to rotate around the central axis of the hinge shaft 1 through the driven link 3. This causes the hinge shaft 2 to drive the pick-and-place actuator to translate horizontally. When the speed and rotation angle of the drive motor 2 and drive motor 3 are the same but opposite in direction, the drive shaft 1 and drive shaft 2 are both stationary relative to the fixed shaft. The driven bevel gear 1 and driven bevel gear 2 drive the active link 2 and active link 3 of the parallelogram mechanism 1 to rotate around the central axis of the connecting shaft 1 and the central axis of the connecting shaft 2 respectively. This causes the hinge shaft 3 to move in the vertical direction, and then drives the hinge shaft 2 to move in the vertical direction through the driven link 3. This causes the hinge shaft 2 to move in the vertical direction, and thus the hinge shaft 2 drives the pick-and-place actuator to move in the vertical direction.

[0018] Preferably, the work trajectory for picking up, translating, and placing items on the work platform from the conveyor belt adopts a zigzag motion trajectory. When the conveyor belt transports the item to the target position on the conveyor belt, the controller controls drive motor one to rotate forward by a preset angle one, which drives drive linkage one to rotate in reverse around the central axis of the fixed shaft through a spur gear pair. Drive linkage one drives driven linkage one, driven linkage two, hinge shaft two, and driven linkage three to rotate around their respective rotational central axes through hinge shaft one, and translate in the horizontal plane. This, in turn, drives the pick-and-place actuator to translate in the horizontal plane through hinge shaft two, thereby moving the pick-and-place actuator directly above the conveyor belt. Then, the controller controls drive motor two and drive motor three to rotate in the same direction at the same speed. The torque generated by drive motor two on drive shaft one through bevel gear pair one and connecting shaft pair is equal to the torque generated by drive motor three on drive shaft two through bevel gear pair two and connecting shaft two, thereby making drive shaft one and drive shaft two rotate synchronously around the central axis of the fixed shaft. Thus, drive shaft one drives drive linkage one through connecting shaft one. The second active linkage rotates clockwise or counterclockwise around the central axis of the fixed shaft. The second drive shaft drives the third active linkage to rotate clockwise or counterclockwise synchronously around the central axis of the fixed shaft via the second connecting shaft. This, in turn, drives the third hinge shaft to rotate clockwise or counterclockwise around the central axis of the fixed shaft. The third hinge shaft, via the third driven linkage, moves the second hinge shaft and the pick-and-place actuator to translate, adjusting the position of the pick-and-place actuator so that it is positioned above the item. The controller controls the output shafts of the second and third drive motors to rotate in opposite directions at the same speed, with the output shaft of the second drive motor rotating clockwise by a preset angle of 2. The output shaft of drive motor three reverses at a preset angle two. Drive motor two drives connecting shaft one through bevel gear pair one, causing active connecting rod two to rotate downward. Drive motor three drives connecting shaft two through bevel gear pair two, causing active connecting rod three to rotate downward synchronously. In turn, active connecting rod two and active connecting rod three cause hinge shaft three to move downward. Hinged shaft three drives driven connecting rod one and driven connecting rod two to rotate downward synchronously through driven connecting rod three and hinge shaft two. In turn, hinge shaft two causes the pick-and-place actuator to descend to contact the item, and the pick-and-place actuator picks up the item.

[0019] Then, the controller controls the output shafts of drive motor 2 and drive motor 3 to rotate in opposite directions at the same speed. Drive motor 2's output shaft rotates in reverse by a preset angle of 2, while drive motor 3's output shaft rotates forward by a preset angle of 2. Drive motor 2 drives connecting shaft 1 via bevel gear pair 1, causing active connecting rod 2 to rotate upward. Drive motor 3 drives connecting shaft 2 via bevel gear pair 2, causing active connecting rod 3 to rotate upward synchronously. This, in turn, causes active connecting rod 2 and active connecting rod 3 to rotate hinge shaft 3 upward. Hinge shaft 3, through driven connecting rod 3 and hinge shaft 2, causes driven connecting rod 1 and driven connecting rod 2 to rotate upward synchronously. This, in turn, causes the object to rise to its initial height via hinge shaft 2 and the pick-and-place actuator. The controller then controls drive motor 1 to rotate in reverse by a preset angle of 1, driving active connecting rod 1 to rotate forward around the central axis of the fixed shaft via a spur gear pair. Active connecting rod 1, through hinge shaft 1, causes driven connecting rod 1, driven connecting rod 2, hinge shaft 2, and driven connecting rod 3 to rotate around their respective rotational central axes, and then rotates horizontally... The device moves horizontally across the surface, and then, via hinge shaft two, moves the pick-and-place actuator and the item horizontally, bringing them above the work platform. The controller then controls the output shafts of drive motors two and three to rotate in the same direction at the same speed, adjusting the position of the pick-and-place actuator and the item so that the item is above the target position on the work platform. The controller then controls the output shafts of drive motors two and three to rotate in opposite directions at the same speed, with drive motor two rotating clockwise by a preset angle of three and drive motor three rotating counterclockwise by a preset angle of three, causing hinge shaft two to lower the pick-and-place actuator and the item until the item contacts the work platform. The pick-and-place actuator then releases the item, which is placed on the work platform. Finally, the controller controls the output shafts of drive motors two and three to rotate in opposite directions at the same speed, with drive motor two rotating counterclockwise by a preset angle of three and drive motor two rotating clockwise by a preset angle of three, causing hinge shaft two to raise the pick-and-place actuator to the initial height.

[0020] The present invention has the following beneficial effects:

[0021] 1. This invention proposes a novel parallel robot configuration that arranges two branches with spatial degrees of freedom antisymmetrically. The resulting form and position constraints transmit the motion of the drive motors to the end effector (hinged axis two), enabling three-degree-of-freedom translational motion at the end effector. This prevents the pick-and-place actuator mounted at the end effector from deflecting relative to the horizontal plane during translation, ensuring the stability required for transferring items. Furthermore, in this invention, each drive motor is mounted on the base, demonstrating the low inertia advantage of the parallel mechanism.

[0022] 2. Compared with the Delta parallel robot, the present invention has fewer parts, uses only two branches, has high dynamic performance, and a simpler envelope shape. Furthermore, the two branches in the present invention are arranged anti-symmetrically, resulting in a compact structure. Compared with the circumferential arrangement of three branches in the Delta parallel robot, it occupies less space, has higher space utilization efficiency, and makes the installation method no longer limited to the gantry crane mode of the Delta parallel robot, enabling flexible installation and arrangement in actual production.

[0023] 3. The two branches in this invention are arranged in an antisymmetric manner. By utilizing the parallelism of opposite sides of a parallelogram, the motion of the driven link is mapped to the active link, thereby enabling direct control of all links. Furthermore, this invention reduces the object of motion control from the entire parallel mechanism with multi-branch closed-loop characteristics to a single branch with serial motion characteristics, thereby reducing nonlinear coupling in kinematics and dynamics and lowering the difficulty of algorithm development. Compared with existing mainstream parallel mechanisms, this invention has significant technical advantages.

[0024] 4. The motion characteristics of an anti-symmetrical parallel mechanism are equivalent to a single branch, with a larger motion space and greater motion flexibility. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0026] Figure 2 This is a schematic diagram of the structure of the base, fixed shaft, connecting shaft one, connecting shaft two, drive shaft one, and drive shaft two in this invention;

[0027] Figure 3 This is a simplified structural diagram of branch one and branch two in this invention;

[0028] Figure 4 This is a simplified structural diagram of branch one in this invention;

[0029] Figure 5 A simplified structural diagram of a planar antisymmetric parallel configuration;

[0030] Figure 6 A simplified structural diagram of a planar symmetrical parallel configuration;

[0031] Figure 7 This is a simplified structural diagram of the tandem configuration;

[0032] Figure 8 This is a schematic diagram of the structure of the present invention during operation. Detailed Implementation

[0033] The present invention will now be further described with reference to the accompanying drawings.

[0034] like Figure 1 and Figure 2 As shown, the present invention discloses an anti-symmetric parallel robot for pick-and-place operations, comprising a base 1, a first branch, a second branch, and a drive assembly. The first branch includes an active link 3, a hinge shaft 4, a driven link 5-1, a driven link 5-2, and a hinge shaft 6; the second branch includes a drive shaft 7-1, a drive shaft 7-2, a connecting shaft 8-1, a connecting shaft 8-2, an active link 9-1, an active link 9-2, a hinge shaft 10, and a driven link 11; the drive assembly includes a drive motor 12, a drive motor 13, a drive motor 14, a spur gear pair, a bevel gear pair 1, and a bevel gear pair 2.

[0035] A fixed shaft 2 is fixed on the base 1; one end of the active connecting rod 3, which is perpendicular to the fixed shaft 2, is hinged to the middle of the fixed shaft 2 and is driven by a drive motor 12 on the base 1 through a spur gear pair, and the output shaft of the drive motor 12 is parallel to the fixed shaft 2; the other end of the active connecting rod 3 is hinged to the middle of the hinge shaft 4, and both ends of the hinge shaft 4 are respectively hinged to one end of the driven connecting rod 5-1 and the driven connecting rod 5-2, and the driven connecting rod 5-1 is parallel to the driven connecting rod 5-2; the other ends of the driven connecting rod 5-1 and the driven connecting rod 5-2 are respectively hinged to both ends of the hinge shaft 6. Drive shaft 7-1 and drive shaft 7-2 are symmetrically arranged on both sides of the active connecting rod 3 and coaxially arranged with the fixed shaft 2. The ends of drive shaft 7-1 and drive shaft 7-2 near the active connecting rod 3 and the two ends of the fixed shaft 2 respectively form a revolute joint. Connecting shaft 8-1 and connecting shaft 8-2, which are parallel to and perpendicular to the fixed shaft 2, respectively form a revolute joint with the ends of drive shaft 7-1 and drive shaft 7-2 away from the active connecting rod 3. Drive motor 1 is mounted on the base 1. 3 and drive motor 14 are driven by bevel gear pair 1 and bevel gear pair 2 respectively, and the output shafts of drive motor 2 13 and drive motor 3 14 are coaxially arranged with fixed shaft 2; one end of the parallel active connecting rod 2 9-1 and active connecting rod 3 9-2 is fixed to connecting shaft 1 8-1 and connecting shaft 2 8-2 respectively, and the other end is hinged to both ends of hinge shaft 3 10 respectively; the driven connecting rod 3 11, which is parallel to the active connecting rod 1 3, is hinged to the middle part of hinge shaft 3 10 and hinge shaft 2 6 respectively.

[0036] In this configuration, the transmission ratios of bevel gear pair one and bevel gear pair two are equal; fixed shaft 2, hinge shaft one 4, hinge shaft two 6, drive shaft one 7-1, drive shaft two 7-2, and hinge shaft three 10 are arranged in parallel. For example... Figure 3 and Figure 4As shown, rod A is an assembly composed of fixed shaft 2, drive shaft 1 7-1, drive shaft 2 7-2, connecting shaft 1 8-1, and connecting shaft 2 8-2; rod B is active connecting rod 2 9-1; rod C is active connecting rod 3 9-2; rod D is hinge shaft 3 10; rod E is hinge shaft 1 4; rod F is driven connecting rod 1 5-1; rod G is driven connecting rod 2 5-2; rod H is hinge shaft 2 6; rod I is active connecting rod 1 3; rod J is driven connecting rod 3 11; and virtual rod K is an active connecting rod. The line connecting the hinge center of hinge 13 and hinge axis 14 to the hinge center of driven link 31 and hinge axis 26; the virtual link L is the line connecting the hinge center of driving link 13 and fixed axis 2 to the hinge center of driven link 31 and hinge axis 30; links A, B, C, and D constitute parallelogram mechanism one; links E, F, G, and H constitute parallelogram mechanism two; virtual links L, I, J, and K constitute parallelogram mechanism three with virtual links; as... Figure 5 , Figure 6 and Figure 7 As shown, the planar symmetrical parallel configuration consists of two symmetrically arranged series configurations, the planar antisymmetric parallel configuration consists of two antisymmetrically arranged series configurations, and the planar antisymmetric parallel configuration is evolved from the planar symmetrical parallel configuration. Branch 1 and branch 2 are arranged antisymmetrically, and the component composed of branch 1 and branch 2 consists of three planar antisymmetric parallel configurations.

[0037] In a preferred embodiment, the spur gear pair includes a driving spur gear 15-1 and a driven spur gear 15-2. The driven spur gear 15-2 forms a rotating pair with the fixed shaft 2 and is fixed to the driving connecting rod 3. The driving spur gear 15-1 forms a rotating pair with the base 1 and meshes with the driven spur gear 15-2, and is driven by the drive motor 12.

[0038] In a preferred embodiment, the bevel gear pair includes a driving bevel gear 16-1 and a driven bevel gear 16-2. The driven bevel gear 16-2 is fixed on the connecting shaft 8-1. The driving bevel gear 16-1 and the base 1 form a rotating pair and mesh with the driven bevel gear 16-2, and are driven by the drive motor 13.

[0039] In a preferred embodiment, the second bevel gear pair includes a driving bevel gear 17-1 and a driven bevel gear 17-2. The driven bevel gear 17-2 is fixed on the connecting shaft 8-2. The driving bevel gear 17-1 forms a rotating pair with the base 1 and meshes with the driven bevel gear 17-2, and is driven by the drive motor 14.

[0040] Among them, drive motor 12, drive motor 2 13 and drive motor 3 14 are all controlled by the controller.

[0041] like Figure 8As shown, the present invention discloses a working method for an antisymmetric parallel robot used for pick-and-place operations, which is as follows:

[0042] The base 1 is installed on the mounting column 18 next to the conveyor mechanism, and the fixed shaft 2, hinge shaft 4, drive shaft 7-1 and drive shaft 7-2 are all in a vertical state. The drive motor 13 is located above the drive motor 14. The pick-and-place actuator (such as a pneumatic suction cup) is coaxially installed at the lower end of the hinge shaft 6. In the initial state, the pick-and-place actuator is located directly above the work platform next to the conveyor mechanism 19, and the driven link 5-1, driven link 5-2, drive link 9-1 and drive link 9-2 are all in a horizontal state. When the conveyor belt 19 transports the item 20 to the target position on the conveyor belt 19 and stops, the controller controls the drive motor 12, drive motor 13 and drive motor 14 to cooperate. Through the parallelogram mechanism 1, parallelogram mechanism 2 and parallelogram mechanism 3, the hinge shaft 26 drives the pick-and-place actuator to translate and lift, completing the operation of picking up the item from the conveyor belt 19, translating the item and placing the item on the work platform. Moreover, the pick-and-place actuator driven by the hinge shaft 26 will not deflect relative to the horizontal plane during the translation and lifting process, thus ensuring the stability required when the item 20 is transferred.

[0043] Among them, the output shaft of drive motor 12 rotates in the forward direction ( Figure 1 In the top view, when the output shaft of drive motor 12 rotates clockwise (forward rotation) or reverses, drive motor 12 drives the active connecting rod 3 through the spur gear pair, causing the hinge shaft 4 to rotate in reverse or forward around the central axis of the fixed shaft 2. Consequently, driven connecting rod 5-1, driven connecting rod 5-2, hinge shaft 6, and driven connecting rod 11 rotate around their respective rotation center axes and translate on the horizontal plane, thereby driving the pick-and-place actuator to translate on the horizontal plane.

[0044] In parallelogram mechanism one, the driving links 2-1 and 3-2 remain parallel throughout their motion. Similarly, the driven bevel gears 1-16-2 and 2-17-2, which have fixed relationships with the driving links 2-1 and 3-2 respectively, also move synchronously. Therefore, bevel gear pair one and two form a bevel gear differential transmission mechanism. The driving bevel gears 1-16-1 and 2-17-1 of bevel gear pair one and two are driven by drive motor 2-13 and drive motor 3-14 respectively. In this bevel gear differential transmission mechanism, the driven bevel gears 1-16-2 and 2-17-2 both rotate about the central axes of connecting shaft 1-8-1 and connecting shaft 2-8-2 respectively, and also revolve about the central axis of fixed shaft 2, thus giving parallelogram mechanism one two degrees of freedom of motion.

[0045] When the rotation angle of drive motor 2 is 'a' and the rotation angle of drive motor 3 is 'b', driven bevel gear 16-2 drives drive linkage 2 9-1 and drive shaft 1 7-1 to rotate around fixed shaft 2 via connecting shaft 1 8-1. Driven bevel gear 17-2 drives drive linkage 3 9-2 and drive shaft 2 7-2 to rotate around fixed shaft 2 via connecting shaft 2 8-2. This causes the parallelogram mechanism 1 as a whole to revolve around the central axis of fixed shaft 2, with a rotation angle of (a+b) / 2. Driven bevel gear 16-2 The driving link 2 9-1 rotates around the central axis of the driving link 2 8-1 via the connecting shaft 1 8-1. The driven bevel gear 2 17-2 drives the driving link 3 9-2 to rotate around the central axis of the connecting shaft 2 8-2 via the connecting shaft 2 8-2. The rotation angles of the driving links 2 9-1 and 3 9-2 around the connecting shafts 1 8-1 and 2 8-2 are both (ba) / 2. Therefore, when the speed, rotation angle, and direction of the drive motors 2 and 3 are the same, the driving links 1 8-1 and 2 8-2 will rotate... 2. Drive shaft 1 (7-1) and drive shaft 2 (7-2) are stationary relative to each other. Parallelogram mechanism 1 rotates around the central axis of fixed shaft 2, and drives parallelogram mechanism 1 to rotate around the central axis of hinge shaft 4 through driven link 3 (11). This causes hinge shaft 2 (6) to drive the pick-and-place actuator to translate horizontally, realizing the horizontal translation of the pick-and-place actuator. When the speed and rotation angle of drive motor 2 and drive motor 3 are the same but opposite in direction, drive shaft 1 (7-1) and drive shaft 2 (7-2) are both relative to fixed shaft 2. When relatively stationary, driven bevel gear 16-2 and driven bevel gear 217-2 drive the active connecting rod 29-1 and active connecting rod 39-2 of parallelogram mechanism 1 to rotate around the central axis of connecting shaft 18-1 and connecting shaft 28-2, respectively. This causes hinge shaft 310 to move vertically, which in turn drives hinge shaft 26 to move vertically through driven connecting rod 311. As a result, hinge shaft 26 drives the pick-and-place actuator to move vertically, thus realizing the lifting and lowering action of the pick-and-place actuator in the vertical direction.

[0046] In this embodiment, a gate-shaped motion trajectory is used to pick up and place items 20. When the conveyor belt 19 conveys items 20 to the target position on the conveyor belt 19, the controller controls the drive motor 12 to rotate forward by a preset angle 1. Through the spur gear pair, the active connecting rod 3 rotates in reverse around the central axis of the fixed shaft 2. The active connecting rod 3 drives the driven connecting rod 5-1, driven connecting rod 5-2, driven shaft 6, and driven connecting rod 11 to rotate around their respective rotation center axes and translate on the horizontal plane. This, in turn, drives the pick-up and place actuator to translate on the horizontal plane through the driven shaft 6, thereby driving the pick-up and place actuator to translate. The actuator moves to a position directly above the conveyor mechanism 19. Then, the controller controls the output shafts of drive motor 13 and drive motor 14 to rotate in the same direction at the same speed. The torque generated by drive motor 13 on drive shaft 7-1 through bevel gear pair 1 and connecting shaft 8-1 is equal to the torque generated by drive motor 14 on drive shaft 7-2 through bevel gear pair 2 and connecting shaft 8-2. This causes drive shaft 7-1 and drive shaft 7-2 to rotate synchronously around the central axis of fixed shaft 2. Consequently, drive shaft 7-1 drives the active connecting rod 9-1 to rotate clockwise around the central axis of fixed shaft 2 via connecting shaft 8-1. Alternatively, in reverse, drive shaft 2 7-2 drives active linkage 3 9-2 to rotate synchronously forward or backward around the central axis of fixed shaft 2 via connecting shaft 2 8-2, thereby driving hinge shaft 3 10 to rotate forward or backward around the central axis of fixed shaft 2. Hinged shaft 3 10 drives hinge shaft 2 6 and the pick-and-place actuator to translate via driven linkage 3 11, adjusting the position of the pick-and-place actuator so that it is translated above the item 20. The controller controls the output shafts of drive motor 2 13 and drive motor 3 14 to rotate in opposite directions at the same speed, with drive motor 2 13's output shaft rotating forward by a preset angle 2 and drive motor 3 14's output shaft rotating backward by a preset angle. Second, drive motor 13 drives connecting shaft 8-1 through bevel gear pair 1 to drive active link 9-1 to rotate downward. Drive motor 14 drives connecting shaft 8-2 through bevel gear pair 2 to drive active link 9-2 to rotate downward synchronously. Then, active link 9-1 and active link 9-2 drive hinge shaft 10 to move downward. Hinge shaft 10 drives driven link 5-1 and driven link 5-2 to rotate downward synchronously through driven link 11 and hinge shaft 6. Then, through hinge shaft 6, the pick-and-place actuator descends to contact the item 20, and the pick-and-place actuator picks up the item 20.

[0047] Then, the controller controls the output shafts of drive motor 2 (13) and drive motor 3 (14) to rotate in opposite directions at the same speed. The output shaft of drive motor 2 (13) rotates in reverse by a preset angle of 2, and the output shaft of drive motor 3 (14) rotates forward by a preset angle of 2. Drive motor 2 (13) drives connecting shaft 1 (8-1) through bevel gear pair 1 to drive active connecting rod 2 (9-1) to rotate upward. Drive motor 3 (14) drives connecting shaft 2 (8-2) through bevel gear pair 2 to drive active connecting rod 3 (9-2) to rotate upward synchronously. In turn, active connecting rod 2 (9-1) and active connecting rod 3 (9-2) drive hinge shaft 3 (10) upward. The rotation of hinge shaft 3 10, via driven link 3 11 and hinge shaft 2 6, drives driven link 1 5-1 and driven link 2 5-2 to rotate upwards synchronously, thereby driving item 20 to rise to the initial height via hinge shaft 2 6 and the pick-and-place actuator; the controller controls drive motor 1 12 to reverse the preset angle 1, driving drive link 1 3 to rotate clockwise around the central axis of fixed shaft 2 via spur gear pair, drive drive link 1 3 to rotate clockwise around the central axis of fixed shaft 2, drive link 1 3 via hinge shaft 1 4 to drive driven link 1 5-1, driven link 2 5-2, hinge shaft 2 6 and driven link 3 11 to rotate around the corresponding axis. The central axis rotates and translates horizontally, thereby driving the pick-and-place actuator and the item 20 to translate horizontally via the hinge shaft 26, thus moving the pick-and-place actuator and the item 20 above the work platform; the controller controls the output shafts of drive motor 213 and drive motor 314 to rotate in the same direction at the same speed, adjusting the position of the pick-and-place actuator and the item 20, so that the item 20 is moved above the target position on the work platform; the controller controls the output shafts of drive motor 213 and drive motor 314 to rotate in opposite directions at the same speed, and drive motor 213 outputs... The output shaft rotates forward by a preset angle of three, and the output shaft of drive motor 14 rotates in reverse by a preset angle of three, causing hinge shaft 26 to drive the pick-and-place actuator and the item 20 to descend until the item 20 contacts the work platform. The pick-and-place actuator releases the item 20, and the item 20 is placed on the work platform. The controller controls the output shafts of drive motor 23 and drive motor 34 to rotate in opposite directions at the same speed, and the output shaft of drive motor 23 rotates in reverse by a preset angle of three, and the output shaft of drive motor 23 rotates forward by a preset angle of three, causing hinge shaft 26 to drive the pick-and-place actuator to rise to the initial height.

Claims

1. An antisymmetric parallel robot for pick-and-place operations, characterized in that: The system includes a base, a first branch, a second branch, and a drive assembly. The first branch includes a first driving link, a first hinge shaft, a first driven link, a second driven link, and a second hinge shaft. The second branch includes a first drive shaft, a second drive shaft, a first connecting shaft, a second connecting shaft, a second driving link, a third driving link, a third hinge shaft, and a third driven link. The drive assembly includes a first drive motor, a second drive motor, a third drive motor, a spur gear pair, a first bevel gear pair, and a second bevel gear pair. A fixed shaft is fixed to the base. One end of the first driving link, perpendicular to the fixed shaft, is hinged to the middle of the fixed shaft and driven by the first drive motor on the base via a spur gear pair; the output shaft of the first drive motor is parallel to the fixed shaft. The other end of the first driving link is hinged to the middle of the first hinge shaft; both ends of the first hinge shaft are hinged to one end of each of the first and second driven links, respectively; the first driven link is parallel to the second driven link. The other ends of connecting rod one and driven connecting rod two are respectively hinged to the two ends of hinge shaft two; driving shaft one and driving shaft two are symmetrically arranged on both sides of driving connecting rod one and are coaxial with the fixed shaft, and the ends of driving shaft one and driving shaft two near driving connecting rod one and the two ends of the fixed shaft respectively form a revolute pair; connecting shaft one and connecting shaft two, which are parallel to and perpendicular to the fixed shaft, respectively form a revolute pair with the ends of driving shaft one and driving shaft two away from driving connecting rod one, and are driven by driving motor two and driving motor three, which are mounted on the base, respectively through bevel gear pair one and bevel gear pair two, and the output shafts of driving motor two and driving motor three are coaxial with the fixed shaft; one end of driving connecting rod two and driving connecting rod three, which are arranged in parallel, is fixed to connecting shaft one and connecting shaft two respectively, and the other end is respectively hinged to the two ends of hinge shaft three; the two ends of driven connecting rod three, which is parallel to driving connecting rod one, are respectively hinged to the middle parts of hinge shaft three and hinge shaft two; In this configuration, the transmission ratios of bevel gear pair 1 and bevel gear pair 2 are equal; the fixed shaft, hinge shaft 1, hinge shaft 2, drive shaft 1, drive shaft 2, and hinge shaft 3 are arranged in parallel; let rod A be an assembly composed of the fixed shaft, drive shaft 1, drive shaft 2, connecting shaft 1, and connecting shaft 2; rod B be the second driving link; rod C be the third driving link; rod D be the third hinge shaft; rod E be the first hinge shaft; rod F be the first driven link; rod G be the second driven link; rod H be the second hinge shaft; and rod I be the first driving link. J is the driven link three. Virtual link K is the line connecting the hinge center of the driving link one and the hinge axis one to the hinge center of the driven link three and the hinge axis two. Virtual link L is the line connecting the hinge center of the driving link one and the fixed axis to the hinge center of the driven link three and the hinge axis three. Links A, B, C and D constitute parallelogram mechanism one. Links E, F, G and H constitute parallelogram mechanism two. Virtual links L, I, J and K constitute parallelogram mechanism three with virtual links.

2. The anti-symmetric parallel robot for pick-and-place operations according to claim 1, characterized in that: The spur gear pair includes a driving spur gear and a driven spur gear. The driven spur gear forms a rotating pair with the connecting shaft and is fixed to the driving connecting rod. The driving spur gear forms a rotating pair with the base and meshes with the driven spur gear, and is driven by a drive motor.

3. The anti-symmetric parallel robot for pick-and-place operations according to claim 1, characterized in that: The first bevel gear pair includes a first driving bevel gear and a first driven bevel gear. The first driven bevel gear is fixed on the first connecting shaft. The first driving bevel gear and the base form a rotating pair and mesh with the first driven bevel gear, and are driven by the second drive motor.

4. The anti-symmetric parallel robot for pick-and-place operations according to claim 3, characterized in that: The second bevel gear pair includes a second driving bevel gear and a second driven bevel gear. The second driven bevel gear is fixed on the second connecting shaft. The second driving bevel gear and the base form a rotating pair and mesh with the second driven bevel gear, and are driven by the third drive motor.

5. The working method of an antisymmetric parallel robot for pick-and-place operations according to claim 4, characterized in that: Specifically as follows: The base is installed on the mounting column next to the conveyor mechanism, with the fixed shaft, hinge shaft one, drive shaft one, and drive shaft two all in a vertical position. Drive motor two is positioned above drive motor three, and the pick-and-place actuator is coaxially installed at the lower end of hinge shaft two. In the initial state, the pick-and-place actuator is located directly above the work platform next to the conveyor mechanism, and driven linkage one, driven linkage two, driving linkage two, and driving linkage three are all in a horizontal position. When the conveyor mechanism transports the item to the target position on the conveyor mechanism and stops, the controller controls drive motor one, drive motor two, and drive motor three to cooperate. Through parallelogram mechanism one, parallelogram mechanism two, and parallelogram mechanism three, the hinge shaft two drives the pick-and-place actuator to translate and lift, completing the operation of picking up the item from the conveyor mechanism, translating the item, and placing the item on the work platform. The pick-and-place actuator driven by hinge shaft two will not deflect relative to the horizontal plane during the translation and lifting process. When the output shaft of drive motor one rotates forward or reverse, drive motor one drives drive linkage one through spur gear pair to drive hinge shaft one to rotate in reverse or forward around the central axis of fixed shaft. Then driven linkage one, driven linkage two, hinge shaft two and driven linkage three rotate around the corresponding rotation center axis and translate on the horizontal plane, thereby driving the pick-and-place actuator to translate on the horizontal plane. In parallelogram mechanism one, the driving links two and three remain parallel throughout their motion. Similarly, the driven bevel gears one and two, which have fixed relationships with the driving links two and three respectively, also move synchronously. Therefore, bevel gears one and two form a bevel gear differential transmission mechanism. The driving bevel gears one and two are driven by drive motors two and three respectively. In this bevel gear differential transmission mechanism, the driven bevel gears one and two have both rotations around the central axes of connecting shaft one and connecting shaft two, and revolutions around the central axis of a fixed shaft, thus giving parallelogram mechanism one two degrees of freedom of motion. When the rotation angle of drive motor 2 is 'a' and the rotation angle of drive motor 3 is 'b', driven bevel gear 1 drives drive link 2 and drive shaft 1 to rotate around the fixed axis via connecting shaft 1. Driven bevel gear 2 drives drive link 3 and drive shaft 2 to rotate around the fixed axis via connecting shaft 2, thus causing the parallelogram mechanism 1 as a whole to revolve around the central axis of the fixed axis with a rotation angle of (a+b) / 2. Driven bevel gear 1 drives drive link 2 to rotate around the central axis of connecting shaft 1 via connecting shaft 1. Driven bevel gear 2 drives drive link 3 to rotate around the central axis of connecting shaft 2 via connecting shaft 2. The rotation angles of drive link 2 and drive link 3 around connecting shaft 1 and connecting shaft 2 are both (ba) / 2. Therefore, when the speed, rotation angle, and direction of drive motor 2 and drive motor 3 are the same, connecting shaft 1... The connecting shaft 2 is stationary relative to the drive shaft 1 and drive shaft 2 respectively. The parallelogram mechanism 1 rotates around the central axis of the fixed shaft, and drives the parallelogram mechanism 1 to rotate around the central axis of the hinge shaft 1 through the driven link 3. This causes the hinge shaft 2 to drive the pick-and-place actuator to translate horizontally. When the speed and rotation angle of the drive motor 2 and drive motor 3 are the same but opposite in direction, the drive shaft 1 and drive shaft 2 are both stationary relative to the fixed shaft. The driven bevel gear 1 and driven bevel gear 2 drive the active link 2 and active link 3 of the parallelogram mechanism 1 to rotate around the central axis of the connecting shaft 1 and the central axis of the connecting shaft 2 respectively. This causes the hinge shaft 3 to move in the vertical direction, and then drives the hinge shaft 2 to move in the vertical direction through the driven link 3. This causes the hinge shaft 2 to move in the vertical direction, and thus the hinge shaft 2 drives the pick-and-place actuator to move in the vertical direction.

6. The working method of an antisymmetric parallel robot for pick-and-place operations according to claim 5, characterized in that: The operation trajectory for picking up, translating, and placing items on the work platform from the conveyor belt adopts a zigzag motion trajectory. When the conveyor belt transports the item to the target position on the conveyor belt, the controller controls drive motor one to rotate forward by a preset angle one. This drives drive linkage one to rotate in reverse around the central axis of the fixed shaft via a spur gear pair. Drive linkage one drives driven linkage one, driven linkage two, hinge shaft two, and driven linkage three to rotate around their respective rotational central axes and translate in the horizontal plane. This, in turn, drives the pick-and-place actuator to translate in the horizontal plane via hinge shaft two, thereby moving the pick-and-place actuator directly above the conveyor belt. Next, the controller controls drive motor two and drive motor three to rotate in the same direction at the same speed. The torque generated by drive motor two on drive shaft one through bevel gear pair one and connecting shaft pair is equal to the torque generated by drive motor three on drive shaft two through bevel gear pair two and connecting shaft two. This causes drive shaft one and drive shaft two to rotate synchronously around the central axis of the fixed shaft. Thus, drive shaft one drives drive linkage one through connecting shaft one. Linkage 2 rotates clockwise or counterclockwise around the central axis of the fixed shaft. Drive shaft 2, through connecting shaft 2, drives active linkage 3 to rotate clockwise or counterclockwise synchronously around the central axis of the fixed shaft. This, in turn, drives hinge shaft 3 to rotate clockwise or counterclockwise around the central axis of the fixed shaft. Hinge shaft 3, through driven linkage 3, drives hinge shaft 2 and the pick-and-place actuator to translate, adjusting the position of the pick-and-place actuator so that it is positioned above the item. The controller controls the output shafts of drive motor 2 and drive motor 3 to rotate in opposite directions at the same speed, with the output shaft of drive motor 2 rotating clockwise by a preset angle of 2. The output shaft of drive motor three reverses at a preset angle two. Drive motor two drives connecting shaft one through bevel gear pair one, causing active connecting rod two to rotate downward. Drive motor three drives connecting shaft two through bevel gear pair two, causing active connecting rod three to rotate downward synchronously. In turn, active connecting rod two and active connecting rod three cause hinge shaft three to move downward. Hinged shaft three drives driven connecting rod one and driven connecting rod two to rotate downward synchronously through driven connecting rod three and hinge shaft two. In turn, hinge shaft two causes the pick-and-place actuator to descend to contact the item, and the pick-and-place actuator picks up the item. Then, the controller controls the output shafts of drive motor 2 and drive motor 3 to rotate in opposite directions at the same speed. Drive motor 2's output shaft rotates in reverse by a preset angle of 2, while drive motor 3's output shaft rotates forward by a preset angle of 2. Drive motor 2 drives connecting shaft 1 via bevel gear pair 1, causing active connecting rod 2 to rotate upward. Drive motor 3 drives connecting shaft 2 via bevel gear pair 2, causing active connecting rod 3 to rotate upward synchronously. This, in turn, causes active connecting rod 2 and active connecting rod 3 to rotate hinge shaft 3 upward. Hinge shaft 3, through driven connecting rod 3 and hinge shaft 2, causes driven connecting rod 1 and driven connecting rod 2 to rotate upward synchronously. This, in turn, causes the object to rise to its initial height via hinge shaft 2 and the pick-and-place actuator. The controller then controls drive motor 1 to rotate in reverse by a preset angle of 1, driving active connecting rod 1 to rotate forward around the central axis of the fixed shaft via a spur gear pair. Active connecting rod 1, through hinge shaft 1, causes driven connecting rod 1, driven connecting rod 2, hinge shaft 2, and driven connecting rod 3 to rotate around their respective rotational central axes, and then rotates horizontally... The device moves horizontally across the surface, and then, via hinge shaft two, moves the pick-and-place actuator and the item horizontally, bringing them above the work platform. The controller then controls the output shafts of drive motors two and three to rotate in the same direction at the same speed, adjusting the position of the pick-and-place actuator and the item so that the item is above the target position on the work platform. The controller then controls the output shafts of drive motors two and three to rotate in opposite directions at the same speed, with drive motor two rotating clockwise by a preset angle of three and drive motor three rotating counterclockwise by a preset angle of three, causing hinge shaft two to lower the pick-and-place actuator and the item until the item contacts the work platform. The pick-and-place actuator then releases the item, which is placed on the work platform. Finally, the controller controls the output shafts of drive motors two and three to rotate in opposite directions at the same speed, with drive motor two rotating counterclockwise by a preset angle of three and drive motor two rotating clockwise by a preset angle of three, causing hinge shaft two to raise the pick-and-place actuator to the initial height.

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