Puncture and Needle Picking Action of Venipuncture Manipulator / 医用生物力学

Objective To propose a new multi-joint series venipuncture system, explore the mechanics and kinematics-based related control problems involved in needle insertion and needle picking during the puncture process, and verify feasibility of this system. Methods A puncture manipulator was built, and needle displacement control algorithm was proposed by combing with the puncture mechanics model. The the forward kinematics was calculated by using DH method, so as to obtain the tip coordinates. Then the inverse kinematics was calculated by using the geometric method. The forward and inverse processes were closely connected. The position error of the end coordinates before and after needle picking was compared by using the method of kinematics positive solution-inverse solution-re-positive solution. Finally, experimental verification and simulation were conducted by combining with the physical object. Results Through simulation and experiments, accuracy of the theoretical model was verified. The needle insertion algorithm could be used to achieve success with only one needle insertion, which provided theoretical basis for the control of robot arm. The position error before and after needle picking could be controlled within 1 mm from the end trajectory. The end needle tip of robot arm was almost kept fixed during the needle picking process. Therefore, this needle picking scheme was feasible and could basically verify that the needle picking action of robot arm met the accuracy and safety requirements. Conclusions The venipuncture manipulator truly simulates the needle insertion and needle picking action during the puncture process, and can safely and accurately realize the needle insertion and needle picking action with needle tip as the fixed point, indicating that it has certain clinical value.

Experimental Study on Puncture Mechanical Properties of Biomimetic Materials / 医用生物力学

Objective To obtain a more suitable puncture method for venipuncture robot through experiments.Methods By using different puncture speeds and angles for biomimetic materials, the force-time curves by various puncture methods were obtained. Results During puncture process, with the increase of the puncture angle, a smaller puncture force was required. The faster puncture speed would lead to a larger puncture force. Conclusions The 40°-45° puncture angleand the 120-300 mm/min puncture speed should be used for designing the puncture method of venipuncture robot. The results provide references for selecting the puncture angle and speed of the venipuncture robot.