A Direct Error Compensation Technology for Five Degrees of Freedom Hybrid Robot

Abstract

The invention discloses a direct error compensation technique for a five-degree-of-freedom mixed-connected robot. The direct error compensation technique comprises the following steps that a coordinate system is built, parallel mechanism pose error detecting and estimating are conducted, and series rotating head pose error detecting and estimating are conducted; and mixed-connected robot pose error estimating and compensating are conducted, and the pose error of the mixed-connected robot in a work space is detected till the precision meets the requirements. The direct error compensation technique for the five-degree-of-freedom mixed-connected robot combines the characteristics that the work space of a series robot is large and the acceleration and rigidity of a parallel robot are high, aims at high-speed and high-precision machining, has wide application prospects in the machining and manufacturing field under the large-scale non-structural environment and is suitable for robot error compensation.

Description

technical field [0001] The invention relates to an error compensation technology for manufacturing equipment, in particular to a direct error compensation technology for a five-degree-of-freedom hybrid robot, which belongs to the field of robots. Background technique [0002] The five-degree-of-freedom hybrid robot built by a three-degree-of-freedom parallel mechanism and a two-degree-of-freedom serial rotor is a new type of five-axis linkage processing equipment, which combines the large working space of the serial robot and the large acceleration and high rigidity of the parallel robot. , with the goal of high-speed and high-precision machining, has broad application prospects in the field of processing and manufacturing in large-scale unstructured environments. Five-degree-of-freedom hybrid robots such as Tricept and Exechon have been initially applied in aerospace, automobile manufacturing and other fields, and have achieved good results. [0003] Accuracy is an importa...

AI Technical Summary

Problems solved by technology

In the past, the above method can still meet the engineering requirements in occasions where the accuracy requirement is not high. However, with the gradual improvement of the accuracy requirements for this type of equipment, the above traditional compensation method can no longer make the equipment achieve the required accuracy.

The main reasons are as follows: First, the number of joints of this type of five-degree-of-freedom hybrid robot is large, and there are six error sources in each joint, and there are multiple structural errors between joints, so there are many error sources. Geometric error sources, the model is too complex and will lead to over-parameterization of the model, which affects the identification accuracy. If only part of the geometric error sources are considered, the error characteristics of the equipment cannot be accurately described; second, the aforementioned error model can only consider the geometric error of the equipment However, the measured value of the terminal pose error obtained in the error detection link not only includes the influence of the geometric error source, but also includes the static deformation error caused by the gravity field, the thermal deformation error caused by the change of the temperature field, etc. Neglecting such errors will lead to error identification results Deviate from the true value, so that it is impossible to accurately estimate the error compensation value of the hybrid robot at any pose; third, the existing error compensation technology steps are cumbersome, and the error accumulation phenomenon is serious, which restricts the improvement of compensation accuracy. As a result, the model cannot accurately describe the real mechanism, the measurement noise is introduced in the measurement link, and the calculation error caused by the data fitting technology used in the error identification link, etc.

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