多种路径形式组合的柔性针二维路径优化

2D Path Optimization for Flexible Needle Based on Combination of Multiform Paths

针对斜尖柔性针在二维组织中的路径优化问题,首先引入了针的Unicycle运动学模型,并利用旋量理论和指数积方程计算了运动学正解,从运动学的角度证明了穿刺直线路径的可行性。基于运动学模型,分析了柔性针穿刺路径的形式,考虑入针姿态的优化,提出了采用多种路径形式组合的路径优化算法,建立了优化目标函数。在有无障碍两种情况下分别对针的穿刺路径进行了优化计算和仿真研究。仿真结果证明,采用该算法能有效地绕过障碍,准确达到靶点,并保证路径最优。在通常临床情况下,最优路径一般为控制度为2的包含直线形式的路径。

Aiming at the path optimization of bevel tip flexible needle in 2D tissue,firstly,the Unicycle kinematic model was introduced for the needle,and then the forward kinematics was calculated using screw theory and product of exponentials formula.The feasibility of linear path was proved through kinematic calculation.On the basis of the kinematic model,the path styles were analyzed,and a novel path planning algorithm was proposed based on combination of the multiform paths,and the objective function was established taking account of the optimization of needle insertion pose.Then the optimal calculation and simulation were performed under the environments with and without obstacles respectively.Simulation results show that this algorithm effectively makes the needle steer clear of obstacles and reaches the target precisely,and guarantees the optimal path,which usually contains a linear path with control degree of 2 in common cliniol conditions.