Dapeng Zhang

Remote-controlled vascular interventional surgery robot

Conventional vascular interventional surgery (VIS) is manually performed under fluoroscopic guidance, requiring lead protection for the surgeons. A remote‐control vascular interventional surgery robot (VISR) which can remotely, safely and precisely perform VIS would have clear advantages.

Overview of the vascular interventional robot.

Conventional vascular interventional surgery (VIS) is manually performed under fluoroscopic guidance, requiring lead protection for the surgeons. In order to reduce the X‐ray irradiation, the robot has been introduced to VIS in this study. The purpose of this article is to provide a comprehensive summary of the vascular interventional robot (VIR).

High Precision Automatic Assembly Based on Microscopic Vision and Force Information

An automatic system is developed to realize high precision assembly of two components in the size of mm level with an interference fit in 3-dimensional (3-D) space with 6-degree-of- freedoms (DOF), which consists of a manipulator, an adjusting platform, a sensing system and a computer. The manipulator is employed to align component B to the component A in position. The adjusting platform aligns the component A to component B in orientations and inserts A into B. The sensing system includes three microscopes and a force sensor. The three microscopes are mounted approximately orthogonal to observe components from different directions in the aligning stage. The force sensor is introduced to detect the contact force in assembly process. In the aligning stage, a pose control method based on image Jacobian matrix is proposed. In the insertion stage, a position control method based on the contact force is proposed. The calibration of image Jacobian matrix is also presented. Experimental results demonstrate the effectiveness of the proposed system and methods.

Vascular deformation for vascular interventional surgery simulation.

Obtaining the expertise to perform minimally vascular interventional surgery (VIS) requires thorough training. Previous VIS simulators have generally assumed that blood vessels are rigid. However, vascular deformation occurs unavoidably in VIS. In this study, the arterial walls were analysed as soft tissue.

Application study of medical robots in vascular intervention

Based on the background of minimally invasive surgery and applications of medical robots, a vascular interventional robotic system has been developed that can be used in the field of vascular intervention.

Relative Pose Estimation for Alignment of Long Cylindrical Components Based on Microscopic Vision

In this paper, an efficient relative pose estimation method based on multimicroscopic vision is presented for the alignment of long cylindrical components in six degree-of-freedom in the 3-D space. First, the relative pose estimation method measures the relative orientation errors between components in a coarse-to-fine manner. The coarse relative orientation estimation reflects the average orientation difference among multiedges and it promises the relative orientation errors can converge to a limited extent rapidly. The fine relative orientation estimation is to detect whether the components will interfere with each other in the insertion process and it provides higher orientation measurement accuracy under multilateral constraint circumstance. The method to determine the invisible feature lines of long cylindrical components of prism shape with odd edges for relative position error estimation is discussed in detail. Afterward, the relative position between components is measured by side-view cameras using the feature lines. In addition, the method to calibrate the optical axis of microscopic camera is also presented. The relative pose estimation method can reliably estimate the relative pose between long cylindrical components of prism shape with odd edges. Alignment experiments and results demonstrate the effectiveness of the proposed relative pose estimation method.

Nanoliter Fluid Dispensing Based on Microscopic Vision and Laser Range Sensor

In this paper, a comprehensive fluid dispensing approach is proposed for nanoliter fluid dispensing, which is based on multimicroscopic vision and laser range sensor. In the dispensing task, fluid needs to be dispensed into target holes with diameter of 300xa0μm. Totally, 21 nanoliter fluid is needed for one dispensing task. To precisely control the fluid volume dispensed, an accurate time–pressure dispensing model is developed for a specific dispensing prototype and the fluid dot altitude is measured by laser range sensor to reflect the dispensed fluid volume. An automatic microfluid dispensing system is developed to verify the effectiveness of the proposed fluid dispensing method. Experiments and results demonstrate that: with the proposed dispensing method and system, dispensing accuracy of 100 pl is achieved, and the fluid dot altitude can be controlled with error range less than 2xa0μm.

A kinematics modeling and stress analysis method for flexible micro-gripper

Considering the demand on gripping small objects in the micro-assembly and micro-manipulation, we design a monolithic micro-gripper based on flexure hinge and driven by piezoelectric. To overcome the limited displacement of PZT-actuators, dual-stage amplification mechanism is utilized to obtain the large output-displacement. And Parallel four-bar linkage is used to realize parallel clamping. The kinematics modeling method and stress analysis using the pseudo-rigid-body-model (PRBM) and compliant mechanisms are discussed in detail. We get the relationship between the input and output displacement and the stress distribution of the flexible hinges which effectively reduces the time of the mechanical structure design. Finite element method (FEM) was performed to verify the feasibility of this method.

Contour Primitives of Interest Extraction Method for Microscopic Images and Its Application on Pose Measurement

This paper proposes a suite of methods to realize high precision pose measurement in 3-D Cartesian space based on a multicamera microscopic vision system. Since it is inefficient to develop a specific image algorithm for each kind of object and the imaging condition might be unsatisfactory, we propose a method of contour primitives of interest extraction, which allows flexible reconfiguration for novel object image and owns robustness under different imaging conditions. The object is detected in grayscale image based on a template of contour primitives. Edges are extracted according to derivatives along the normal vectors of these contour primitives. The positions and directional derivatives of these edges are used for feature extraction and autofocus, respectively. The point features and line features extracted from multiview images are utilized to measure 3-D vectors and orientations, respectively, based on image Jacobian matrices. Cameras’ linear motions are considered in the imaging model, so that the measurement range is expanded beyond the limitation of microscopes’ shallow depths of field. The affine epipolar constraint and focused planes intersection constraint between cameras are applied to improve the real time performances of image feature extraction and multicamera autofocus, respectively. A series of experiments are conducted to verify the effectiveness of the proposed methods. The root mean square errors of pose measurement are evaluated as 3

Laser Beam Pointing Control With Piezoelectric Actuator Model Learning

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