Workpiece following grabbing locus planning method and system used for high-speed sorting system

Abstract

The invention discloses a workpiece following grabbing locus planning method and system used for a high-speed sorting system. The method comprises steps of establishing a following grabbing locus model, acquiring workpiece coordinates, manipulator end coordinates and manipulator movement parameters; according to the workpiece coordinates, determining conditions of workpiece loci and determining acurrent solving interval; according to the current solving interval, determining the interval displacement and a time formula, and determining the value range of a single variable in the interval; according to upper and lower half regions of the working range where the workpiece is arranged, determining a grabbing equation of locus; substituting the displacement and the time formula into the equation of locus; using the bisection method to solve the solution of the equation of the locus in the value range, if there is a solution, according to the equation solution, planning a grabbing locus and executing the grabbing; and if there is no solution, turning to the next solving interval and repeating the solving processes. The beneficial effects are that the working range of the manipulator are fully used; the characteristics of the S curve speed increasing and decreasing algorithm are fully used; grabbing efficiency is improved; and grabbing precision is improved.

Description

technical field [0001] The invention relates to the field of motion control of a computer numerical control system, in particular to a method and system for planning a tracking and grabbing track of a workpiece used in a high-speed sorting system. Background technique [0002] Workpiece sorting is an important link in the modern factory assembly line. A robot sorting system generally includes the following equipment: manipulators, conveyor belts, workpiece trays, controllers, and industrial cameras. The industrial camera obtains the position information of the workpiece by collecting the image of the workpiece on the conveyor belt and transmits the workpiece information to the robot controller. The controller performs grasping path planning and speed planning, and then controls the manipulator to periodically interpolate the planned grasping trajectory. The traditional grabbing path generally adopts a "gate"-shaped trajectory. When acquiring the grabbing command, the end of...

AI Technical Summary

Problems solved by technology

However, the suction and blowing of the suction cup are generally completed by the controller controlling the corresponding IO. The control delay of the IO is much higher than the 1ms interpolation of the manipulator. The delay of the IO control makes it impossible to perform the grasping action in time when the manipulator reaches the top of the workpiece. The workpiece continues to move along the direction of the conveyor belt for a certain distance. When the IO performs grabbing, the grabbing position has deviated from the original calculation position, resulting in the grabbing position not being in the center of the workpiece, which reduces the accuracy of the grabbing position and the placement accuracy. On the other hand, due to the uneven surface of the conveyor belt, the height information of the workpiece in the robot coordinate system fluctuates and is difficult to judge. The fluctuating height information brings great difficulties to the setting of the gripping height. To pick up the workpiece, the height of the suction cup must be as close as possible to the upper surface of the workpiece, so as to ensure that the accuracy of the grasping position is not affected

[0003] The prior art proposes the control idea of ​​adjusting the speed of the conveyor belt according to the distribution density of workpieces on the conveyor belt to ensure that the robot is always in the state of the fastest grabbing speed, and a simple theoretical analysis is carried out, but this method is difficult to implement. And it does not meet the production process that requires the production cycle

[0004] The existing technology proposes to use the modified trapezoidal algorithm as the acceleration and deceleration algorithm of the robot. Although the algorithm is simple in calculation, due to the unreasonable time allocation of the modified trapezoidal algorithm itself, its movement in a short period of time is jumpy, and its long-distance movement performance is weak. characteristics, insufficient dynamic characteristics, it is difficult to ensure high-efficiency grasping

[0005] To sum up, there is still a lack of effective solutions to the problem of how to further effectively track moving targets and improve grasping efficiency in existing technologies

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