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Parallel mechanism has the advantages of large stiffness，fast response and high precision， which is suitable for suspension field. A new type of parallel mechanism for automobile multi-link suspension is proposed， the kinematic model of the mechanism is established， combined with the screw theory， the spatial motion characteristics of the mechanism are analyzed through the pose parameters， and the screw amount representing the motion is approximately even. Combined with the kinematics concept of the automobile suspension， the wheel positioning parameters are given using the homogeneous transformation matrix. The instantaneous kinematic analysis method of the suspension is proposed using the screw theory.

In order to improve the accuracy of conical target pose parameters measured by monocular vision, we propose a high precision visual measurement method for conical target based on the minimum reconstruction error of 3D. Firstly, we select the main and auxiliary features used for pose parameters' measurement by analyzing target's imaging process. Secondly, the algebraic and geometric methods for measuring pose parameters are determined based on the selected features. Finally, we utilize the geometric constraints of target to establish the reconstruction error formula and optimize the pose parameters based on the minimum reconstruction error principle to improve the measurement accuracy. To verify the effectiveness of our method, we use 3ds Max software to generate target's simulation images under different pose parameters and compare the pose parameters before and after optimization. Experimental results show that the proposed method can significantly improve the accuracy of pose parameters when the measurement distance is far (more than 30 m), which is up to about 40%. [ABSTRACT FROM AUTHOR]

Nowadays, due to the advantages of non-contact and high-speed, vision-based pose measurements have been widely used for aircraft performance testing in a wind tunnel. However, usually glass ports are used to protect cameras against the high-speed airflow influence, which will lead to a big measurement error. In this paper, to further improve the vision-based pose measurement accuracy, an imaging model which considers the refraction light of the observation window was proposed. In this method, a nonlinear camera calibration model considering the refraction brought by the wind tunnel observation window, was established first. What’s more, a new method for the linear calibration of the normal vector of the glass observation window was presented. Then, combining with the proposed matching method based on coplanarity constraint, the six pose parameters of the falling target could be calculated. Finally, the experimental setup was established to conduct the pose measurement study in the laboratory, and the results satisfied the application requirements. Besides, experiments for verifying the vision measurement accuracy were also performed, and the results indicated that the displacement and angle measurement accuracy approximately increased by 57% and 33.6%, respectively, which showed the high accuracy of the proposed method.

Nowadays, due to the advantages of non-contact and high-speed, vision-based pose measurements have been widely used for aircraft performance testing in a wind tunnel. However, usually glass ports are used to protect cameras against the high-speed airflow influence, which will lead to a big measurement error. In this paper, to further improve the vision-based pose measurement accuracy, an imaging model which considers the refraction light of the observation window was proposed. In this method, a nonlinear camera calibration model considering the refraction brought by the wind tunnel observation window, was established first. What's more, a new method for the linear calibration of the normal vector of the glass observation window was presented. Then, combining with the proposed matching method based on coplanarity constraint, the six pose parameters of the falling target could be calculated. Finally, the experimental setup was established to conduct the pose measurement study in the laboratory, and the results satisfied the application requirements. Besides, experiments for verifying the vision measurement accuracy were also performed, and the results indicated that the displacement and angle measurement accuracy approximately increased by 57% and 33.6%, respectively, which showed the high accuracy of the proposed method. [ABSTRACT FROM AUTHOR]