A collaborative handling control method for multiple mobile robots

Abstract

The present invention discloses a method for controlling the collaborative handling of multiple mobile robots, in which no tracking is required during the movement of the robots and no hardware connection is required between the robots. The invention uses a laser scanner with a wide measurement range and high precision to achieve collaborative positioning of multiple groups of pilot-follower robots, and can solve the relative posture of the two vehicles under any posture; the formation control technology used is particularly suitable for the transportation requirements of maintaining the formation shape, and the relative posture of each vehicle during the transportation process can be controlled to change within a very small range; the tracking control technology used combines the correction requirements with the driving capability, ensuring the rapid elimination of errors under the limited driving capability of the AGV, while giving full play to the omnidirectional mobility advantages of the AGV.

Description

Technical Field

[0001] The present invention relates to the field of intelligent industrial logistics technology, in particular to a trackless collaborative transport control technology for multiple mobile robots. Background Art

[0002] In the current aerospace manufacturing industry, the transportation and docking of super-large and super-heavy sections are mainly carried out manually and by rail-guided vehicles (RGVs). Manual lifting is inefficient, involves many repetitive tasks, and is less safe. The RGV track is fixed on the ground, which reduces the flexibility of transportation. In response to the demand for flexible ground transportation of large indoor sections, even if AGVs are used for transportation in some scenarios, the customized design of such AGVs has a low degree of reuse and product adaptability. Summary of the invention

[0003] In response to the above technical problems, the present invention aims to provide a multi-mobile robot trackless collaborative transport control technology, using mobile robots with a high degree of intelligence for transport, thereby improving the transport efficiency of the entire system.

[0004] The present invention provides a multi-mobile robot collaborative handling control method, the control method comprising the following steps:

[0005] Obtain the location information of the slave vehicle through the laser scanner on the master vehicle;

[0006] Solve the actual relative posture of the master vehicle and the slave vehicle according to the position information of the slave vehicle, and determine the standard posture of the slave vehicle relative to the master vehicle according to the shape of the formation to be formed;

[0007] The position deviation d is obtained based on the actual relative posture of the master vehicle and the slave vehicle and the standard posture. e and the angle deviation θ e ;

[0008] The centerline speed of the vehicle should be The direction points to the standard position point, and the direction angle is θ; the angular velocity of the slave vehicle should be ω=f2(θ e ), where f1 and f2 are PID functions related to position deviation and angle deviation respectively;

[0009] According to the AGV motion characteristics, the center speed is decomposed and the speed vector of each wheel is expressed as in is the linear velocity, P i Indicates the position information of each wheel in the vehicle coordinate system;

[0010] Assume the maximum driving capacity of the driving wheel is v max , if exists Resolve the center velocity and angular velocity; set the center line velocity and angular velocity as unknown quantities and use Get multiple inequalities, solve each inequality and take the intersection of the results, that is, find the new decomposition that meets the driving capacity constraints with ω;

[0011] The AGV moves according to the driving speed obtained by the solution, and the relative posture is adjusted. The entire formation will maintain formation and move towards the destination under the leadership of the main vehicle.

[0012] Furthermore, a laser scanner capable of identifying the position of reflective marks is used. The laser scanner is installed on the master vehicle and the reflective marks are installed on the slave vehicle. The relative position [x inM y inM ] and actual relative posture α.

[0013] Furthermore, the position information of the slave vehicle is obtained by using the laser scanner on the master vehicle:

[0014] The laser scanner on the main vehicle obtains the position information of the reflective mark of the slave vehicle in the main vehicle coordinate system and sets Represents the rotation matrix between the scanner laser scanner and the host vehicle coordinate system, and the position of the reflective mark of the slave vehicle in the host vehicle coordinate system:

[0015]

[0016] Wherein, i is the reflective marking number;

[0017] Furthermore, the actual relative posture of the master vehicle and the slave vehicle is solved according to the position information of the reflective mark of the slave vehicle, and the standard posture of the slave vehicle relative to the master vehicle is determined according to the shape of the formation to be formed.

[0018] Solving equations The actual relative position of the master and slave vehicles (x inM y inM );

[0019] Using the formula The actual relative posture of the master and the servant can be obtained.

[0020] Furthermore, the position deviation d is solved according to the actual relative posture of the master and slave and the standard posture of the master and slave e and the angle deviation θ e , specifically θ e =α-α d .

[0021] Beneficial Effects

[0022] Compared with traditional oversized and overweight transfer technology, this method has the following advantages:

[0023] 1) Use highly intelligent mobile robots for transportation to improve the transportation efficiency of the entire system;

[0024] 2) The mobile robots in the formation are of the same model, which is easy to maintain and upgrade. At the same time, the average load of each vehicle is low, which reduces the design difficulty;

[0025] 3) Multiple vehicles can adjust their formation according to the shape of the workpiece, and have high adaptability to multiple products. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the collaborative handling control structure of multiple mobile robots in this application. DETAILED DESCRIPTION

[0027] In order to facilitate ordinary technicians in the field to understand and implement the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the examples described herein are only used to illustrate and explain the present invention, and are not limited to the present invention.

[0028] The present invention provides

[0029] The laser scanner is installed on the main vehicle. The origin of the laser scanner coordinate system can be expressed in the main vehicle coordinate system as (x s y s ), the laser scanner coordinate system and the main vehicle coordinate system have an attitude angle δ s ; Install two sets of reflective markers on the slave vehicle. The installation position in the slave vehicle coordinate system can be expressed as (a p1 b p1 )、(a p2 b p2 );

[0030] The laser scanner can feedback the reflective mark position information (L1β1) and (L2β2), L i is the distance measurement, β i is the angle measurement value,

[0031] The relative posture is the actual posture of the slave vehicle relative to the main vehicle obtained by the laser scanner measurement value; the standard posture refers to the posture state of the slave vehicle relative to the main vehicle determined by the shape of the formation to be formed, which is the standard value of the aforementioned relative posture.

[0032] use Represents the rotation matrix between the scanner and the main vehicle coordinate system, and the position of the reflective mark in the main vehicle coordinate system can be obtained: are the positions of the reflective mark in the main vehicle coordinate system, which corresponds to (L i , β i ), the points (L1β1) and (L2β2) in the laser scanner coordinates are transformed into the main vehicle coordinate system and expressed as

[0033] Solving equations The actual relative position of the master and slave vehicles (x inM y inM ); further, the actual relative posture can be obtained

[0034] The position coordinates of the origin of the standard position coordinate system of the slave vehicle in the coordinate system of the master vehicle can be determined by the shape of the formation to be formed. The standard position coordinate system and the main vehicle coordinate system have an attitude angle α d ;

[0035] The position deviation d can be obtained from the actual relative position of the master and slave and the standard position of the master and slave e and the angle deviation θ e ,in θ e =α-α d .

[0036] In order to achieve the purpose of stabilizing the formation and eliminating deviation, the centerline speed of the car The direction points to the standard position point; the vehicle should have an angular velocity ω=f2(d e ), where f1 and f2 are PID functions related to position deviation and angle deviation respectively.

[0037] The center velocity and angular velocity values ​​can be calculated by combining the previously obtained posture deviation and angle deviation with the PID parameters. "Center" refers to the velocity starting point (vector) located at the origin of the vehicle coordinate system after the coordinate system line is established for the vehicle.

[0038] According to the motion characteristics of AGV, the center speed is decomposed and the speed vector of each wheel can be expressed as Where P i It represents the position information of each wheel in the body coordinate system of the slave vehicle; Pi is the frame parameter, which represents the position information of each wheel in the body coordinate system and can be directly measured or provided by the robot manufacturer.

[0039] Assume the maximum driving capacity of the driving wheel is v max , when a round speed meets the condition The center velocity and angular velocity should be re-solved. Set the center line velocity and angular velocity as unknown quantities and use Multiple inequalities can be obtained. Solving each inequality and taking the intersection of the results can obtain a new decomposition that satisfies the driving capacity constraints. With ω.

[0040] The AGV moves according to the driving speed obtained by the solution, and the relative posture is adjusted. The entire formation will maintain formation and move towards the destination under the leadership of the main vehicle.

[0041] It should be understood that the parts not elaborated in detail in this specification belong to the prior art. It should be understood that the above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modification, equivalent substitution, deformation, etc. made within the spirit and principle of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A method for controlling collaborative transport of multiple mobile robots, characterized in that: The control method comprises the following steps: Obtain the location information of the slave vehicle through the laser scanner on the master vehicle; Solve the actual relative posture of the master vehicle and the slave vehicle according to the position information of the slave vehicle, and determine the standard posture of the slave vehicle relative to the master vehicle according to the shape of the formation to be formed; The position deviation d is obtained based on the actual relative posture of the master vehicle and the slave vehicle and the standard posture. e and the angle deviation θ e ; The centerline speed of the vehicle should be The direction points to the standard position point, and the direction angle is θ; the angular velocity of the slave vehicle should be ω=f2(θ e ), where f1 and f2 are PID functions related to position deviation and angle deviation respectively; According to the AGV motion characteristics, the center speed is decomposed and the speed vector of each wheel is expressed as in is the linear velocity, P i Indicates the position information of each wheel in the vehicle coordinate system; Assume the maximum driving capacity of the driving wheel is v max , if exists Resolve the center velocity and angular velocity; set the center line velocity and angular velocity as unknown quantities and use Get multiple inequalities, solve each inequality and take the intersection of the results, that is, find the new decomposition that meets the driving capacity constraints with ω; The AGV moves according to the driving speed obtained by the solution, and the relative posture is adjusted. The entire formation will maintain formation and move towards the destination under the leadership of the main vehicle.

2. A method for controlling collaborative transport of multiple mobile robots according to claim 1, characterized in that: A laser scanner that can identify the position of reflective marks is used. The laser scanner is installed on the master vehicle and the reflective marks are installed on the slave vehicle. The relative position [x inM y inM ] and actual relative posture α.

3. A method for controlling collaborative transport of multiple mobile robots according to claim 1, characterized in that: The laser scanner on the master vehicle is used to obtain the position information of the slave vehicle: The laser scanner on the main vehicle obtains the position information of the reflective mark of the slave vehicle in the main vehicle coordinate system and sets Represents the rotation matrix between the scanner laser scanner and the host vehicle coordinate system, and the position of the reflective mark of the slave vehicle in the host vehicle coordinate system: Wherein, i is the reflective mark number.

4. A method for controlling collaborative transport of multiple mobile robots according to claim 1, characterized in that: The actual relative position of the master vehicle and the slave vehicle is solved according to the position information of the reflective mark of the slave vehicle, and the standard position of the slave vehicle relative to the master vehicle is determined according to the shape of the formation to be formed, and the equation is solved. The actual relative position of the master and slave vehicles (x inM y inM ); using the formula The actual relative posture of the master and the servant can be obtained.

5. The method for controlling collaborative transport of multiple mobile robots according to claim 1, characterized in that: Solve the position deviation d according to the actual relative posture of the master and slave and the standard posture of the master and slave e and the angle deviation θ e , specifically θ e =α-α d .

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