Mechanical arm kinematics parameter calibration method based on inertial measurement unit

Abstract

A mechanical arm kinematics parameter calibration method based on an inertial measurement unit comprises the steps that firstly, the relation expression among the linear speed under a mechanical arm tail end Cartesian coordinates, the speed relation under the joint space and the jacobian matrix is constructed, and derivation is conducted; secondly, normalization processing is conducted on the derived relational expression; thirdly, the linear acceleration under the mechanical arm tail end Cartesian space and the angle, the angle speed and the angle acceleration under the mechanical arm joint space are obtained; fourthly, the recursive least-squares method is utilized for conducting mechanical arm parameter identification, and the mechanical arm kinematics parameter calculated value in eachdirection is obtained; and fifthly, the root-mean-square value is obtained from the obtained three values, the mechanical arm kinematics parameter final estimated value at the time is output, and a curve is drawn. By means of the mechanical arm kinematics parameter calibration method, the mechanical arm kinematics calibration cost is reduced. Along with constant improvement of the inertial measurement unit technology, the measuring precision is higher and higher, the precision of the calibration result is higher and higher, and the mechanical arm kinematics parameter calibration method has wider development prospects.

Description

technical field [0001] The invention relates to the technical field of robots, in particular to a method for calibrating kinematic parameters of a manipulator based on an inertial measurement unit. Background technique [0002] There are many factors that affect the positioning accuracy of the end of the industrial robot, and among these errors, the error caused by the geometric parameters is the system error, and it is also the main factor that causes the absolute positioning accuracy of the manipulator to be low. In order not to change the hardware configuration of the manipulator, it is the most economical method to identify the kinematic parameters of the manipulator. [0003] In the model-based kinematics calibration method of the manipulator, end effectors are needed, such as laser tracker, three-coordinate measuring instrument, ballbar and so on. Newman W S et al. completed the kinematic calibration of the P8 robot with a laser tracker. Rencheng Wang et al. only inst...

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Problems solved by technology

Secondly, the instrument is a non-contact calibration, so it has high requirements on the continuity of the laser, but in practice, the light will often be cut off and re-measurement will be required, resulting in the low measurement efficiency of this method; finally, the current measurement The number of products is small, and the cost is often several million, so the economic performance is poor for small-scale calibration experiments. In addition, in terms of patent literature, CN106799745A, an industrial manipulator arm precision calibration method based on collaborative kriging, discloses a method using The calibration device composed of a laser tracker and a target ball, the target ball is fixed at the end of the mechanical arm, still has the above defects

The CMM occupies a large area and is expensive

Publication number CN110561424A, an online robot kinematics calibration method based on a multi-sensor hybrid filter, although the inertial measurement unit is used publicly, it is mainly aimed at estimating the position and attitude of the robot end, and the factorial quaternion algorithm estimation process is adopted. Using Euler angles to represent the attitude is not a direct measurement of the kinematic parameters of the robotic arm. Error compensation is required, and the estimation process is more complicated.

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