KR-102963925-B1 - Stable rectangular object gripping method using a gripper with three fingers, computing device, recording medium thereof

KR102963925B1KR 102963925 B1KR102963925 B1KR 102963925B1KR-102963925-B1

Abstract

One embodiment relates to a method for gripping a square object using a three-finger gripper in which three fingers of the gripper are arranged at 120-degree intervals and each finger moves along a reference line extending from the origin of the gripper to the center point of the finger, comprising: a first step of determining whether the gripper grips two or three sides of the square object; a second step of determining whether the fingers are located at the corner of the object if, in the determination of the first step, it is determined that the gripper grips two sides of the object; and a third step of moving the center of the gripper by a certain distance (d) if, as a result of the determination of the third step, the fingers are located at the corner of the object, wherein the certain distance is the solution to an inequality in which the radius (r) of the fingers, the horizontal length (w) and the vertical length (h) of the object are variables.

Inventors

김창환
김승희
이진휘
김효정
박성기
김동환

Assignees

한국과학기술연구원

Dates

Publication Date: 20260512
Application Date: 20231128

Claims (11)

The present invention relates to a method for gripping a square object using a three-finger gripper, wherein three fingers of the gripper are arranged at 120-degree intervals and each finger moves along a reference line extending from the origin of the gripper to the center point of the finger. A first step of determining whether the gripper grasps two or three sides of the square object; In the determination of the first step above, if it is determined that the gripper grasps two surfaces of the object, a second step of determining whether the finger is located at the edge of the object; and, A third step in which, based on the result of the judgment in the second step above, if the finger is located at the corner of the object, the center of the gripper is moved by a certain distance (d). Includes, The above constant distance is the solution to an inequality with the radius (r) of the finger, the width (w) and the length (h) of the object as variables, Method of gripping a square object with a 3-finger gripper.
In paragraph 1, In the first step above, the determination of the two-sided gripping or three-sided gripping is based on an inequality in which the horizontal length and the vertical length of the object are variables, a method for gripping a square object with a three-finger gripper.
In paragraph 2, In the judgment of the first step above, the two-sided grip is A square object gripping method that satisfies the condition.
In paragraph 3, In the judgment of the second step above, whether the finger is located at the corner is A square object gripping method that satisfies the condition.
In paragraph 4, The above constant distance (d) is A square object gripping method obtained to satisfy the conditions.
A memory storing a program for controlling the operation of a three-finger gripper, wherein three fingers of the gripper are arranged at 120-degree intervals and each finger moves along a reference line extending from the origin of the gripper to the center point of the finger; and It includes a processor that controls the operation of the above-mentioned three-finger gripper according to a Singi program, and The above processor is, It is determined whether the above 3-finger gripper grasps two or three sides of a square object, and if it is determined that the gripper grasps two sides of the object, it is determined whether the finger is located at the corner of the object. As a result of determining the corner position, if the finger is located at the corner of the object, the center of the gripper is moved by a certain distance (d), and The above constant distance is the solution to an inequality with the radius (r) of the finger, the width (w) and the length (h) of the object as variables, computing unit.
In paragraph 6, The processor is a computing device in which the determination of the two-sided gripping or three-sided gripping is based on an inequality in which the horizontal length of the object and the vertical length of the object are variables.
In Paragraph 7, The above processor, the above two-sided gripping An arithmetic unit that satisfies the condition of
In paragraph 8, The above processor determines whether the finger is located at an edge A computational unit based on the conditions of.
In Paragraph 9, The above processor, the above constant distance (d) An arithmetic unit that performs operations to satisfy the conditions of
A recording medium that records the method of grasping a square object of a three-finger gripper described in any one of paragraphs 1 to 5 so that a computer can execute it.

Description

Stable rectangular object gripping method using a three-finger gripper, computing device, and recording medium thereof The present invention relates to a method for stably gripping a square object using a three-fingered gripper and a recording medium thereof. A means for grasping objects, such as robots, is generally called a gripper. Depending on the number of fingers that grasp an object, grippers are referred to as three-finger or four-finger grippers, and the present invention relates to a three-finger gripper. A 3-finger gripper is a gripper with three fingers spaced 120 degrees apart. It can stably grip triangular and circular objects, but for quadrilateral objects, since the number of faces of the object is greater than the number of fingers, not all fingers of the gripper can directly contact all four faces of the object. Therefore, to ensure a stable grip, a gripping point with force equilibrium must be calculated. Conventionally, in order to ensure stable gripping, it is common practice to align the center of the gripper with the center of the object (based on x,y) before performing the gripping operation; however, in this case, the fingers of the gripper may be positioned at the corners of the square object, resulting in unstable gripping of the object. Therefore, it is necessary to determine the object position and the gripper position by considering the size of the object. The prior art related to the present invention is described below. Prior Art 1: KR Registration No. 10-1116279 "Person/Object Identification Device Using a Sensor" discloses a technology for tracking moving objects by identifying objects through color matching based on moving areas in an image and correcting their position by additionally using a Kalman filter. However, this prior art 1 has a technical limitation in that it is difficult to distinguish between people wearing the same clothes because it only matches using RGB colors. Prior Art 2: KR Publication No. 10-2020-0046178 "Head Region Detection Method and Head Region Detection Device" discloses a technology that feeds an image cropped into a human region into an artificial intelligence model to extract feature vector values, compares the extracted feature vector values to identify the one with the most similar value as the same person. However, this prior art 2 has a problem in that it is highly likely to identify the same person if they are wearing the same clothes. FIG. 1 is a schematic diagram illustrating the movement of a gripper that is the subject of the motion control method according to the present invention. Figure 2 is a diagram schematically illustrating a two-sided gripping case. Figure 3 is a drawing showing the case where the finger is located at the corner in a two-sided gripping case. Figure 4 is a diagram schematically illustrating a three-sided gripping case. Figure 5 is a drawing showing the case where the finger is located at the corner in a three-sided gripping case. Figure 6 shows the distance according to the variable when the gripper is moved by d. FIG. 7 is a flowchart of a method for gripping a square object using a three-finger gripper according to a temporary example. FIG. 8 is a block diagram of a computational device according to a temporary example. Embodiments of the present invention will be described in detail below with reference to the drawings. However, detailed descriptions of known functions or configurations that may obscure the essence of the present invention in the following description and the attached drawings are omitted. Additionally, throughout the specification, the term 'comprising' a component means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Additionally, terms such as first, second, etc. may be used to describe various components, but said components should not be limited by said terms. said terms may be used for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be named the second component, and similarly, the second component may be named the first component. The terms used in this invention are used merely to describe specific embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, terms such as "comprising" or "comprising" are intended to specify the existence of the described features, numbers, steps, actions, components, parts, or combinations thereof, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof. Unless specifically defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the presen