Robot assembly automatic hole searching method based on force feedback

Abstract

The invention discloses a robot assembly automatic hole searching method based on force feedback, and belongs to the technical field of industrial robot intelligent control; visual image processing isnot needed; and based on six-dimensional force sensor feedback information, a deviated direction and a deviated distance of a hole relative to a shaft are reasonably estimated to plan hole searchingpolicies. Through size values of the shaft and the hole in assembly, mathematical relations corresponding to the deviated distance and an equivalent force arm one to one are calculated before control.Magnitudes of horizontal torque and axial force on a horizontal plane are obtained through six-dimensional sensor monitoring force signals in the control process to calculate the equivalent force armin the hole searching process; and then, the deviated distance is determined according to a relation between the equivalent force arm and the deviated distance. Meanwhile, a corrected deviated direction is obtained according to the magnitude of each component of the torque; and then, a variable-step-length adjusting scheme is adopted according to the known deviated distance and deviated directionto realize the hole searching scheme. Finally, the shaft is inserted in the hole actively and smoothly by using a admittance control principle after the hole searching process is finished. The methodhas the following advantages: complicated visual image processing is not needed; and high efficiency and generality are achieved.

Description

technical field [0001] The invention belongs to the technical field of intelligent control of industrial robots, and specifically relates to an automatic hole-seeking method for robot assembly based on force feedback. Based on the feedback information of a six-dimensional force sensor, the offset direction and offset distance of the hole relative to the axis can be reasonably estimated, and the hole-seeking method can be planned. hole strategy. Background technique [0002] In industrial tasks, shaft hole assembly is one of the most common industrial operations. During the initial contact process of the shaft hole, the first problem faced is "shaft hole alignment", that is, the problem of "automatic hole finding". With the improvement of the degree of intelligence, for the situation where the initial position is inaccurate and there is a certain error in the center position of the shaft and the hole, the assembly task cannot be completed only by simple position control, it i...

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Problems solved by technology

[0003] For the hole-finding process, there are currently two methods. One is to use visual information to calculate the relative position of the shaft hole in real time through image processing. However, this method requires real-time processing of image information, which requires high processing frequency for industrial assembly controllers. , which is generally difficult to meet in ordinary industrial tasks; the other is to use the force feedback information of the six-dimensional force sensor to move in a constant step according to the direction obtained from the torque value, but this method will have low efficiency and non-universal The low efficiency is reflected in the slow adjustment process of the uniform step size, and the non-universality is reflected in the inability to adapt to all shaft hole clearances under the condition of a small deviation and a large adjustment step.

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