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Objectives: The high-precision registration of point cloud data is the key to ensure the integrity of 3D data on the surface of spatial objects. To address the problem that there are differences in position, attitude and scale of cloud data from neighboring stations, a method is proposed to solve the registration model of point cloud described by the dual quaternion under the constraints of point-planar feature. Methods: First, the rotation matrix and translation vector of the spatially similar transformation are represented by the dual quaternion, based on which the scale factor is taken into account and the vertical and parallel spatial topological relationships exist between the vectors constructed by the points in the plane and the points out of the plane respectively and the normal vectors of the plane, and this is used as the constraint of the spatially similar transformation to construct the parity model based on the least squares criterion. Then the Levenberg-Marquardt method is introduced to solve the level-difference model to avoid the possible non-convergence of the iterations in the level-difference treatment due to the inappropriateness of the initial values or due to the fact that the real symmetric matrix constructed by the Jacobi matrix is close to singularity. Result: Two sets of experiments are compared and analyzed with the existing methods, and the experimental results show that the proposed method can effectively achieve point cloud registration. Conclusions: Therefore, the method that takes into account the scale factor under the point-planar feature constraint and uses the dual quaternion to realize the spatial similarity transformation has a strong practical value. [ABSTRACT FROM AUTHOR]

An integrated attitude-orbit controller based on extended state observer (ESO) is designed for spacecraft to settle down the unavailability of angular velocity and centroid velocity during on?orbit flight.First,the spacecraft’s integrated attitude?orbit kinematics and dynamics model is presented based on dual quaternion.Second,an extended state observer is designed for the case of velocity screw information missing,which takes the model parameter error and external disturbance into account,and the finite time convergence of the observation error is analyzed by using Lyapunov stability theorem.Then a fast terminal sliding mode controller for integrated attitude?orbit control is designed based on the above extended state observer,and its finite time convergence is analyzed.Finally,a numerical simulation is given to verify the effectiveness of the control system. [ABSTRACT FROM AUTHOR]

Aiming at hand-eye calibration problem in robotic hand-eye vision system, the hand-eye conversion relationship between end-effector and camera of manipulator was studied, the method of solving homogeneous matrix in hand-eye calibration was summarized, and a vision model based on motion posture was set up. The improved dual quaternion approach was used for solving separately the rotation parts and the translation of the hand-eye homogeneous transformation matrix. In order to obtain the optimum solution of the translation vector, the infinite norm minimization was introduced during the solving process of translation vector, the local optimal solution of translation vector was obtained by iteration. Simulations based on the considered optimal translation vector algorithm were performed in Matlab, and the classic; solving using dual quaternion and linear decoupling estimation algorithm were also implemented for comparison. The results indicate that the proposed method is better than traditional methods in the precision of calibration, robustness of noise and sensitivity and stability of motion posture numbers. It can meet the accuracy requirement of hand-eye calibration. [ABSTRACT FROM AUTHOR]

In order to improve the precision of the strapdown inertial navigation algorithm based on dual quaternion in the high dynamic environment, a trapezoid digital integral algorithm is applied to compen­sate the coning and sculling errors, which optimizes the attitude and velocity calculating algorithm and improves the calculating precision of the strapdown inertial navigation algorithm. During a sampling period of gyroscope and accelerometer, the angular rates of gyroscope outputs at previous and current times are both integrated by using the trapezoid digital integral algorithm, and the integral angle increment is used for the coning error compensation. The accelerometer outputs at previous and current times are integated by using the trapezoid digital integral algorithm, and the integral velocity increment and the integral angular increment are used for the sculling error compensation. Through the simulation of multi-group dynamic tracks, it is shown that the improved coning and sculling error compensation algorithms adopting the trapezoid digital integration have higher navigation precision than the traditional rectangular digital in­tegration method when the inputs are angular rate and acceleration. The dynamics of the track is higher, and the performance advantage of the improved algorithm is more obvious. The analysis and comparison of kinematic vehicle experimental results further verify the performance advantage of the proposed improved algorithm. [ABSTRACT FROM AUTHOR]

Aiming at the problem of unified coordinate system involved in the robot calibration with the help of laser tracker,the transformation relation between robot nominal base frame and the fitting base frame of spatial geometric method by laser tracker was researched,a calibration method of robot base frame using dual quaternion was proposed and applied.The 7-DOF serial robot kinematics model was established by the product-of-exponential formula,and calibration model for robot base frame using dual quaternion was derived.The results indicate that the calibration method can calculate the rotation and translation of the calibration equation at one time,overcome the error transfer in the traditional pose-step calculation process and improve the calibration accuracy directly.The calibration method is useful to other problem that formulates in the same mathematical form,such as robot hand-eye system calibration and multi-robot coordination. [ABSTRACT FROM AUTHOR]

Both traditional and dual quaternion-based velocity update algorithms for strapdown inertial navigation system (SINS) are comparatively studied. The leading cause of difference in accuracy between the two algorithms is analyzed and determined in principle. By defining both truncation and approximate integral errors, the difference in accuracy can be not only described qualitatively but also computed quantitatively. The validity of theoretical analysis and derivation is verified through simulation testing. The significant superiority of the dual quaternion algorithm over the traditional one in accuracy is demonstrated through simulation results under highly-dynamic and large-maneuver conditions. Comparison results under both ideal and real dynamic conditions show that the dual quaternion algorithm is superior to the traditional one in overall performance. [ABSTRACT FROM AUTHOR]