A multi-robot cooperative mobile transportation method and system

Abstract

This invention discloses a collaborative mobile transportation method and system based on multiple robots, relating to the field of intelligent manufacturing technology. It enables the automated handling and loading / unloading of molds with different grasping and transportation requirements and different sizes and models through the collaborative working relationship of multiple robots. The system of this invention consists of a group of robots with identical or similar structures. The robot manipulation mechanism includes a lifting mechanism S1 and a rotating platform S2. The automated handling and loading / unloading of molds with different grasping and transportation requirements and different sizes and models is achieved through the collaborative working relationship of multiple robots. This invention is applicable to the automated handling and loading / unloading of molds with different grasping and transportation requirements and different sizes and models.

Description

Technical Field

[0001] This invention relates to the field of intelligent manufacturing technology, and in particular to a collaborative mobile transportation method and system based on multiple robots. Background Technology

[0002] In recent years, my country's logistics industry has developed rapidly. Benefiting from artificial intelligence and robotics technologies, the logistics robot industry has also risen rapidly, and the government has successively introduced a number of policies to support the development of the robot industry. With the rapid development of the logistics market, the logistics robot industry has received a rare development opportunity, and the application of logistics robots is rapidly becoming widespread, making it a crucial factor leading the development trend of modern logistics. Different robots are used in different positions in logistics operations; for example, mobile robot technology plays an irreplaceable role in loading and unloading. Loading and unloading is one of the most basic functional elements of the logistics system, existing in the processes of cargo transportation, storage, packaging, distribution processing, and delivery, and permeating the entire logistics operation. The application of mobile robots in loading and unloading operations in logistics directly improves the efficiency and effectiveness of the logistics system.

[0003] Different loading and unloading environments and transported objects place different demands on mobile robots. Some logistics and transportation solutions even require additional heavy infrastructure, such as ground landmarks, AGV rails, or specific stacking and storage racks. Some solutions may require human assistance, such as scissor lifts where objects need to be placed on the transport platform manually, and forklifts where objects need to be stored on pallets in advance manually. Robotic gripper systems, on the other hand, limit the shape and size of the objects being lifted; different robots are needed for loading, unloading, and transporting different objects.

[0004] In aircraft manufacturing, many parts require molds for casting. Different molds are needed to manufacture parts of different sizes, and different transport vehicles are required to transport these molds. For example, small molds are transported using automated guided vehicles (AGVs), while large molds require forklifts. This results in a large variety of transport vehicles of different sizes, leading to significant management challenges. Reducing the number of transport robots would make it difficult to efficiently transport some large molds. Therefore, how to utilize transport robots of the same model to collaboratively transport large components has become a problem that needs to be studied. Summary of the Invention

[0005] The embodiments of the present invention provide a collaborative mobile transportation method and system based on multiple robots, which can realize the automatic handling and loading / unloading of molds with different grasping and transportation requirements and different sizes and models through the collaborative working relationship of multiple robots.

[0006] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0007] In a first aspect, the present invention provides a multi-robot collaborative mobile transportation system, wherein the system consists of at least two robots, and each robot is equipped with a lifting mechanism S1 and a rotating platform S2, wherein the lifting mechanism S1 is installed on the rotating platform S2 of each robot.

[0008] The rotating platform S2 includes a mobile platform (1) and a rotating platform (2). The mobile platform (1) is fixed on the upper surface of the robot, and the rotating platform (2) is connected to the mobile platform (1) through a first rotating shaft.

[0009] The lifting mechanism S1 includes: two parallelogram mechanisms, a first end actuator bracket (5), a second end actuator bracket (6), and an actuator (7);

[0010] Each parallelogram mechanism includes: two parallel connecting rods (4) and a base (3). The bottom ends of the two parallel connecting rods (4) are connected to the base (3) through a second rotating shaft to form a bottom rotating joint. The top ends of the two parallel connecting rods (4) are connected to the first end effector bracket (5) through a third rotating shaft to form a top rotating joint.

[0011] The first end effector bracket (5) adopts a beam structure perpendicular to the two parallelogram mechanisms;

[0012] One end of the second actuator bracket (6) is fixed to the first end actuator bracket (5), and the other end is fixedly connected to one side surface of the actuator (7). The other side surface of the actuator (7) serves as the contact surface that contacts the mold.

[0013] Secondly, the multi-robot collaborative mobile transportation method provided by embodiments of the present invention includes:

[0014] S101. Obtain the maximum total lifting force required to lift the mold to be transported based on its mass;

[0015] S102. Determine the number of robots required to lift the mold to be transported based on the total lifting force required to lift the mold to be transported;

[0016] S103. Control a certain number of robots to approach the mold to be transported until the contact surface of the actuator (7) of each robot contacts the mold to be transported. Then control the lifting mechanism S1 of each robot to run synchronously and lift the mold to be transported. The height of the lifting exceeds the height of the robot's turntable (2).

[0017] S104. Each robot continues to move toward the mold to be transported until a part of the rotating platform (2) of each robot enters the projection of the mold to be transported on the ground. Then, the lifting mechanism S1 of each robot is controlled to run synchronously and lower the mold to be transported until the mold to be transported contacts the rotating platform (2) of each robot.

[0018] S105. Rotate the angles of each robot until the instantaneous center of motion of all robots is consistent.

[0019] The collaborative mobile transportation method and system based on multiple robots provided in this invention consists of a group of robots with identical or similar structures. A predetermined number of robots are controlled to approach the mold to be transported until the contact surfaces of the actuators (7) of each robot contact the mold. Then, the lifting mechanisms S1 of each robot are controlled to operate synchronously and lift the mold to be transported to a height exceeding the height of the robot's rotating platform (2). Each robot continues to move towards the mold until a portion of its rotating platform (2) enters the projection of the mold on the ground. Then, the lifting mechanisms S1 of each robot are controlled to operate synchronously and lower the mold to be transported until it contacts the rotating platform (2) of each robot. This achieves collaborative operation and transportation of the mold. Thus, through the collaborative working relationship of multiple robots, automatic handling and loading / unloading of molds with different grasping and transportation requirements and different sizes and models are achieved. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 The parallelogram mechanism-based scheme is provided in the basic lifting system of the present invention.

[0022] Figure 2 Comprehensive analysis of robot dimensions provided for embodiments of the present invention;

[0023] Figure 3 This is an example of determining the robot trajectory center provided in an embodiment of the present invention;

[0024] Figure 4 This is an example of a singular position of a robot parallelogram mechanism provided in an embodiment of the present invention;

[0025] Figure 5 These are two examples of robots lifting objects provided in embodiments of the present invention;

[0026] Figure 6 The cooperative operation and transportation method provided in the embodiments of the present invention;

[0027] Figure 7 A simplified diagram of the constraints of the robot lifting mechanism provided in an embodiment of the present invention;

[0028] Figure 8 An example of a simulated robot successfully lifting a 40kg object provided in this embodiment of the invention;

[0029] Figure 9 This invention provides a simulation example of using a helical spring to lift an object.

[0030] Figure 10 The simulation provided in this embodiment of the invention uses an interconnection mechanism to enhance object instances;

[0031] Figure 11 This is a schematic diagram of the method flow provided in an embodiment of the present invention. Detailed Implementation

[0032] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Embodiments of the present invention will be described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in the specification of the present invention means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or couplings. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the meaning consistent with their meaning in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0033] The main design objective of this embodiment is to utilize the collaborative nature of mobile transport robots to transport different objects. A collaborative robot system is formed by the cooperative working relationships of multiple robots, and the number of robots required is adjusted according to the shape and weight of the objects to be transported. Therefore, designing a robot that can adapt to all grasping and transport requirements is of great significance. It can not only save on the cost of manufacturing or purchasing robots, but also reduce the time spent changing robots when transporting different objects, thereby improving logistics efficiency.

[0034] Specifically, embodiments of the present invention provide a collaborative mobile transportation system based on multiple robots, such as... Figure 6 As shown, the system consists of at least two robots, and so on. Figure 1 , 8 As shown in Figure 10, each robot is equipped with a lifting mechanism S1 and a rotating platform S2, with the lifting mechanism S1 mounted on the rotating platform S2 of each robot.

[0035] Specifically, such as Figure 7 As shown, the rotating platform S2 includes: a mobile platform (1) and a rotating platform (2). The mobile platform (1) is fixed on the upper surface of the robot, and the rotating platform (2) is connected to the mobile platform (1) through a first rotating shaft. The lifting mechanism S1 includes: two parallelogram mechanisms, a first end effector bracket (5), a second end effector bracket (6), and an actuator (7); wherein, in each parallelogram mechanism, there are: two parallel connecting rods (4) and a base (3). The bottom ends of the two parallel connecting rods (4) are connected to the base (3) through a second rotating shaft to form a bottom rotating joint, wherein the rotating shaft of the rotating joint passes through the base (3). The top ends of the two parallel connecting rods (4) are connected to the first end effector bracket (5) through a third rotating shaft to form a top rotating joint.

[0036] The first end actuator bracket (5) adopts a beam structure perpendicular to the two parallelogram mechanisms; one end of the second end actuator bracket (6) is fixed on the first end actuator bracket (5), and the other end is fixedly connected to one side surface of the actuator (7), with the other side surface of the actuator (7) serving as the contact surface that contacts the mold.

[0037] In this embodiment, the short rod is fixed between the bases (3) of the two parallelogram mechanisms; the short rod, the second rotating shaft, the third rotating shaft, and the first end actuator bracket (5) are parallel to each other. The second end actuator bracket (6) is trapezoidal, with one end of the long side of the trapezoid fixedly connected to one side surface of the actuator (7), and one end of the short side of the trapezoid fixedly connected to the first end actuator bracket (5).

[0038] The actuator (7) provides pressure and friction to the object to ensure its lifting. By using an attachment material (i.e., a rigid contact plate) on it, the coefficient of friction can be maximized, thereby increasing the maximum total lifting force of the collaborative mobile robot. The linkage (8) connects and drives the lower short rod and the upper end effector bracket (5) to move together, enabling the parallelogram mechanism above the entire platform to drive the end effector (7) to perform gripping work. Specifically, the contact surface of the actuator (7) is covered with a rigid contact plate, the material of which is rubber or organic synthetic polymer material; and surface filaments and wear-resistant fillers are attached to the surface of the rigid contact plate, wherein the high wear-resistant filler, such as glass fiber, improves the wear resistance of the rigid contact plate.

[0039] The collaborative mobile transport robot system in this embodiment consists of several robots arranged around an object, adaptable to molds of any size. Before transport begins, the required number of robots is determined based on the size, structure, and mass of the mold to be transported. The system calculates the required number of robots and the position of the object to be manipulated. Each robot is driven independently, using a lifting mechanism to lift and place the object. The robots rotate at appropriate angles to perform the transport operation. In this embodiment, the lifting capacity of the collaborative mobile transport robot system needs to be determined based on factors such as the number of robots, contact characteristics, and forces. Mathematical derivation and calculation show that the lifting capacity of the collaborative mobile transport robot system is positively correlated with the total number of robots (m), their masses (M), and friction coefficients (μp and μg). To increase the lifting capacity f of the collaborative mobile robot... p,t The total number of robots, m, needs to be increased. max Their mass M or coefficient of friction μ g and μ p In practical applications, this collaborative mobile transport robot system exhibits reconfigurability. This reconfigurability is manifested in its ability to automatically modify the composition of the multi-robot system based on the number of individual robots involved and in the event of a failure of one or more individual robots. This reconfigurability includes obtaining a robot configuration set through a positioning algorithm to ensure the stability of the entire system (the object being lifted and several individual robots) across different task steps. Specifically, for better stability, the object should be transported on or as close to the robot body as possible. Using this method ensures that the object's center of gravity is above the robot; keeping the center of gravity as low as possible also ensures better stability when moving on slopes.

[0040] This embodiment also provides a collaborative mobile transportation method based on multiple robots. The method is used in the aforementioned collaborative mobile transportation system with multiple robots, wherein the system includes at least two robots, such as... Figure 6 , 11 As shown, the method includes:

[0041] S101. Obtain the maximum total lifting force required to lift the mold to be transported based on its mass;

[0042] S102. Determine the number of robots required to lift the mold to be transported based on the total lifting force required to lift the mold to be transported;

[0043] S103. Control a certain number of robots to approach the mold to be transported until the contact surface of the actuator (7) of each robot contacts the mold to be transported. Then control the lifting mechanism S1 of each robot to operate synchronously and lift the mold to be transported. The height of the lifting exceeds the height of the robot's turntable (2). Each robot determines the position of the object to be transported and surrounds it using a distance sensor. Each robot faces the object to ensure that the end effector can contact the object. The driving force of the robot makes the end effector contact the object and generate collective pressure on the object at the contact surface.

[0044] S104. Each robot continues to move toward the mold to be transported until a part of the rotating platform (2) of each robot enters the projection of the mold to be transported on the ground. Then, the lifting mechanism S1 of each robot is controlled to operate synchronously and lower the mold to be transported until the mold to be transported contacts the rotating platform (2) of each robot. Under the drive of each robot, pressure and friction are generated between the end effector and the object. The friction is used as the lifting force to lift the object and place it on the top platform of the robot.

[0045] S105. Rotate the angles of each robot until the instantaneous centers of motion of all robots are consistent. Specifically, each robot rotates an appropriate angle to ensure that the collaborative mobile transport robots have a unique instantaneous center of motion.

[0046] In this embodiment, as follows Figure 5 Taking the force application method shown as an example, in S101, the total lifting force required to lift the mold to be transported includes:

[0047] Determine the maximum lifting force provided by each robot during the process of lifting the mold to be transported: f m,p,t =μ p f m,p,n =μ p f m,p,t =μ p (μ g f m,g,n )=μ p (μ g Mg), where the subscript at the right of the parameter symbol j indicates the contact property, including: g for the ground, p for the manipulated object; k indicates the force components, including: n for the normal, t for the tangential. f m,p,n This indicates that a robot of mass M is at contact point C. m,p The pressure applied to the mold to be transported, μ p μ represents the coefficient of friction of the contact surface of the robot's actuator (7). g This indicates that the robot's wheels are at contact point C with the ground. m,gThe coefficient of friction. Therefore, in practical applications, the resulting lifting force f m,p,t Power is provided by the wheels;

[0048] Calculate the total lifting force required to lift the mold to be transported based on the maximum lifting force provided by each robot during the lifting process: m max This indicates the number of robots required to lift the mold to be transported.

[0049] The force applied to the robot is represented by three exponents f. m,j,k Let m be the number of robots, j be the contact type (g is the ground, p is the manipulated object), and k be the force components (n is the normal, t is the tangential). A robot of mass M can be at contact point C. m,p Applying pressure f to an object m,p,n The coefficient of friction is μ p The resulting lifting force f m,p,t Power is provided by the wheels. The wheels contact the ground at point C. m,g The coefficient of friction is μ g Specifically, assuming Therefore, we can conclude that the improvement capability of collaborative mobile robots is related to the total number of robots, m. max m represents the number of robots required, their mass M, and the coefficient of friction. μ p、μ g It is related, and positively correlated. To increase the enhancement capabilities of collaborative mobile robots... p,t The total number of robots, m, must be increased. max Their mass M or coefficient of friction μ g and μ p Because transportation environments are diverse and objects may be made of different materials, the coefficient of friction μ varies. p and μ g It is not precise, and may even be variable.

[0050] In this embodiment, the size and structure of a single robot are determined through mathematical derivation and calculation, such as... Figure 2 As shown, in S103, after the contact surface of the robot's actuator (7) contacts the mold to be transported, the lifting mechanism S1 operates synchronously and lifts the mold to be transported. During this process, the synchronous operation of the lifting mechanism S1 includes the extension of the lifting mechanism S1 of each robot.

[0051] For each robot, during the extension of the lifting mechanism S1, the positional relationship between the two ends of the long rod of the parallelogram mechanism is updated in real time.

[0052] This can be achieved using triangular geometric relationships, where the length of the long rod is equal to the trajectory radius r. Similarly, in a parallelogram mechanism, the length of the long rod is equal to the trajectory radius r, expressed as:

[0053]

[0054] Where r can be solved by the following second-order equation:

[0055] r 2 = (h + rsinα0) 2 +(a+b) 2 (2)

[0056] Where h represents the vertical distance from the robot platform to the ground, α0 represents the angle between the long side (AB side) of the parallelogram mechanism of the robot in the initial state and the horizontal line; a and b represent two constants that can be determined using triangular geometric relationships, and A, B, C, and D represent the four angles of the parallelogram, l AB l CD l AD l BC Let AB, CD, AD, and BC represent the lengths of the parallelogram mechanism, where AB and CD are the longer sides, equal to the radius r of the trajectory; and the shorter sides AD and BC are equal in length.

[0057] Specifically, the parallelogram mechanism parameters are defined as follows: P1: the initial contact point between the robot and the object still on the ground; P2: the final position of the object on the robot platform (this position must ensure the stability of the robot platform); P3: the transition position of the end effector as it passes over the robot platform, defined by gaps δ1 and δ2, to avoid collision between the robot end effector and the moving platform. p : The center of gravity of the mold to be transported; G m Robot's center of gravity; C m,p C m+1,p These are the contact points between the centers of the end effectors of robot m and robot (m+1) and the mold to be transported; C m,g C m+1,g Let P1 be the contact point between the wheels of robot m and robot (m+1), respectively, and the ground; d is the vertical distance from the parallelogram structure to the robot platform; γ is the angle between the short side (BC side) of the parallelogram mechanism and the horizontal line in the initial state of the robot; c is the vertical distance from the foremost point of the parallelogram mechanism to the end effector; and L1 is the vertical distance from point P2 to the mold to be transported. Taking robot m as an example, let C be the contact point between the wheels and the ground. m,g Establish a rectangular coordinate system with the origin, x m z m These are the x and y coordinates, respectively, with the positive direction as shown below. Figure 2As shown, for the robot's mechanical structure, the x-coordinate of point P2 should be less than the x-coordinate of the origin, i.e.

[0058] Furthermore, methods such as Figure 3 The robot trajectory radius is determined in the manner shown, where, for formula (2), the constant a is first determined by the geometric relationship of a right triangle:

[0059] The constants a and b are determined using the geometric relationships of a right triangle, where:

[0060]

[0061] Where P1 and P2 represent the two endpoints of the long rod of the parallelogram mechanism, l represents the horizontal distance from point P2 to the outside of the robot's mobile platform, δ1 and δ2 represent the horizontal and vertical distances from point P3 to the outside of the robot's mobile platform, respectively, δ1 > 0, δ2 > 0; P3 is a point on the movement trajectory of the parallelogram mechanism with radius r; after determining the constants a and b, formula (2) can be re-expressed as a new second-order form of r: m'r 2 +n'r+p'=0(5), and further update the calculation method of r to obtain:

[0062]

[0063] Where m', n', and p' represent the coefficients of the quadratic and linear terms of r in formula (5), respectively.

[0064] Specifically:

[0065]

[0066] Substituting formulas (6), (7), and (8) into formula (5), we can calculate r (represented by m', n', and p'):

[0067]

[0068] Determine the positional relationship between the two endpoints of the long link of the robot's parallelogram mechanism, such as... Figure 2 The distance between P1 and P2 can be expressed by a formula containing a constant parameter:

[0069] L1=A'+rcosα0 (10)

[0070]

[0071] The positional relationship between points P1 and P2 is as follows:

[0072]

[0073] x P1 Let x represent the x-coordinate of point P1. P2 The x-coordinate of point P2 is represented by z. P1 The z-coordinate of point P1 represents the ordinate of point P1. P2 This represents the ordinate of point P2.

[0074] Therefore, the positional relationship between points A and B is:

[0075]

[0076] In this embodiment, for each robot, during the extension of the lifting mechanism S1, the singular position of the parallelogram mechanism is calculated in real time, and the parallelogram mechanism is kept away from the singular position.

[0077] For example Figure 4 As shown, to avoid singular positions in parallelogram mechanisms, The angle requirement must be met:

[0078]

[0079] When the mechanism consistently meets the aforementioned angle requirements during its movement from the initial position to the final position, the parallelogram mechanism will not exhibit [problems]. Figure 4 (a) shows a flat structure. Therefore, γ needs to be selected at a suitable angle to meet the requirements of formula (14).

[0080] In the singular location, the normal vector is represented by γ. The angle between the horizontal and the vertical directions, keeping the range of values ​​for γ as follows: Where α0 and α1 represent the angles of link AB at its two extreme positions. For example Figure 4 As shown in (b), γ is the normal vector. Horizontal direction of AB The included angle between them. To prevent the parallelogram structure from flattening, γ must be less than π-α1. Considering that α0 > 0, the range of values ​​for γ can be derived.

[0081] In practical applications, such as Figure 9 As shown, a helical spring of suitable stiffness is added between points A and B of the parallelogram mechanism for simulation. Initially, the spring is in a compressed state, providing additional pressure to the end effector to stably grip the object. When the end effector lifts the object, the helical spring, due to its stretching, applies tension to the end effector, which can be used to maintain the stability of the cooperative mobile robot. The helical spring generates a normal force due to deformation, applying additional pressure to the object, thereby keeping the object gripped and ensuring the overall system stability. Figure 9 In the diagram, α and β are the angles between the long and short sides of the parallelogram mechanism and the horizontal line, respectively; ψ is the angle between the diagonally connected springs and the vertical direction; F spr F is the force exerted on the spring by the parallelogram mechanism after the spring is connected; spr,t For F spr The component in the vertical direction;

[0082] The feasibility of this embodiment can be verified through experiments. For example, the multibody dynamics simulation software ADAMS can be used to perform dynamic simulations to demonstrate the process of the cooperative mobile transport robot system lifting objects, and to verify and explain the influence of different parameters on the lifting capability of the cooperative mobile robot.

[0083] In the simulation, the parameters were set to be equal to or close to the actual physical parameters. The parameter settings are as follows: static friction coefficient between the end effector and the object (rubber / steel) μp = 0.65; static friction coefficient between the wheel and the ground (rubber / asphalt) μg = 0.8; single robot mass M ≥ 80 kg;

[0084] A constant torque is applied to the wheels of a single robot to drive it forward, ensuring contact between the robot's end effector and the payload, providing pressure and lifting force on the object. A dynamic simulation is performed on a cooperative mobile transport robot using a passive lifting mechanism, simulating the process of the cooperative mobile transport robot lifting an object and placing it on the top platform of the single robot. Figure 8 This demonstrates the motion of a robot successfully lifting a 40kg object under conditions of high frictional contact between the object and the end effector. Dynamic simulations are performed on a cooperative mobile robot using a diagonal helical spring mechanism. Figure 9 This paper introduces the principle of simulating a parallelogram mechanism by adding a helical spring between points A and B: Initially, the spring is compressed, providing additional pressure to the end effector to stably grip the object. When the end effector lifts the object, the helical spring, stretched, applies tension to the end effector, which can be used to maintain the stability of the cooperative transport robot. Connecting the spring tip to the opposite corner of the parallelogram prevents the connecting rod from bending due to additional pressure.

[0085] Simulations of collaborative mobile transport robots using interconnection mechanisms, where the interconnection mechanism allows individual robot end effectors to be interconnected through a virtual system. For example... Figure 10Interconnecting individual robots via an interconnected system ensures that objects can be clamped at all stages without the risk of slippage. Simultaneously, using this interconnection mechanism, a single robot is fully capable of lifting a payload and placing it on its top platform with good stability. In this scenario, the collaborative mobile robot's lifting capacity is limited only by the driving force applied by the individual robot when the manipulator is not activated. When a driving force is applied to the parallelogram mechanism, the mass of the object that a single robot can lift can reach the total weight of the individual robots used.

[0086] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on its differences from other embodiments. In particular, the device embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The above descriptions are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A collaborative mobile transportation method based on multiple robots, characterized in that, The method is used in a multi-robot cooperative mobile transportation system, the system comprising at least two robots, the method comprising: S101. Obtain the maximum total lifting force required to lift the mold to be transported based on its mass; S102. Determine the number of robots required to lift the mold to be transported based on the total lifting force required to lift the mold to be transported; S103. Control a certain number of robots to approach the mold to be transported until the contact surface of the actuator (7) of each robot contacts the mold to be transported. Then control the lifting mechanism S1 of each robot to run synchronously and lift the mold to be transported. The height of the lifting exceeds the height of the robot's turntable (2). S104. Each robot continues to move toward the mold to be transported until a part of the rotating platform (2) of each robot enters the projection of the mold to be transported on the ground. Then, the lifting mechanism S1 of each robot is controlled to run synchronously and lower the mold to be transported until the mold to be transported contacts the rotating platform (2) of each robot. S105. Rotate the angles of each robot until the instantaneous centers of motion of all robots are in sync; In S101, the total lifting force required to lift the mold to be transported is determined, including: Determine the maximum lifting force provided by each robot during the process of lifting the mold to be transported: f m,p,t =μ p f m,p,n =μ p f m,p,t =μ p (m g f m,g,n )=μ p (m g Mg), Among them, f m,p,n This indicates that a robot of mass M is at contact point C. m,p The pressure applied to the mold to be transported, μp represents the coefficient of friction of the contact surface of the robot's actuator (7), and μg represents the coefficient of friction between the robot's wheel and the ground at contact point C. m,g The coefficient of friction; Calculate the total lifting force required to lift the mold to be transported based on the maximum lifting force provided by each robot during the lifting process: m max This indicates the number of robots required to lift the mold to be transported.

2. The method according to claim 1, characterized in that, In S103, after the contact surface of the robot's actuator (7) comes into contact with the mold to be transported, the lifting mechanism S1 operates synchronously and lifts the mold to be transported. During this process, the synchronous operation of the lifting mechanism S1 includes the extension of the lifting mechanism S1 of each robot. For each robot, during the extension of the lifting mechanism S1, the positional relationship between the two ends of the long rod of the parallelogram mechanism is updated in real time. In a parallelogram mechanism, the length of the long link is equal to the radius r of the parallelogram mechanism's trajectory, expressed as: The method for calculating r is as follows: r 2 =(h+rsinα0) 2 +(a+b) 2 (2) Where h represents the vertical distance from the robot platform to the ground, α0 represents the angle between the long side (AB) of the parallelogram mechanism of the robot in its initial state and the horizontal line; a and b represent two constants determined by triangular geometric relationships, and A, B, C, and D represent the four angles of the parallelogram, l AB l CD l AD and l BC These represent the lengths of sides AB, CD, AD, and BC of the parallelogram mechanism, respectively.

3. The method according to claim 2, characterized in that, Also includes: The constants a and b are determined using the geometric relationships of a right triangle, where: Where P1 and P2 represent the two endpoints of the long rod of the parallelogram mechanism, l represents the horizontal distance from point P2 to the outside of the robot's moving platform, δ1 and δ2 represent the horizontal and vertical distances from point P3 to the outside of the robot's moving platform, respectively, δ1>0, δ2>0; P3 is a point on the moving trajectory of the parallelogram mechanism with radius r; after determining the constants a and b, the calculation method of r is updated, and it can be re-expressed as a new second-order formula for r: m'r 2 +n'r+p'=0(5), resulting in: Where m', n', and p' represent the coefficients of the quadratic and linear terms, respectively, and the constant term.

4. The method according to claim 1, characterized in that, Also includes: For each robot, during the extension of the lifting mechanism S1, the singular position of the parallelogram mechanism is calculated in real time, and the parallelogram mechanism is kept away from the singular position. In the singular location, the normal vector is represented by γ. The angle between the horizontal and the vertical directions, keeping the range of values ​​for γ as follows: Where α0 and α1 represent the angles of link AB at its two extreme positions.

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