面向磁性微机器人的三维磁场驱动系统的研究

3D MAGNETIC MANIPULATION SYSTEM FOR ACTUATION OF MAGNETIC MICROROBOT

贾延超

11849017

硕士

机械工程领域工程

胡程志

2020-06-04

2020-07-20

哈尔滨工业大学

深圳

微机器人作为机器人学科的一个重要分支，克服了尺寸的限制，可以在狭小环境中进行特殊操作，这使其在众多领域中得到了广泛的关注。在微机器人的众多驱动方式中，外磁场驱动在驱动效率、磁性材料的获取、生物兼容性、医疗安全等方面具有独特优势，目前在国内外被广泛研究。磁场驱动方式也由最初的匀强磁场、梯度磁场发展到平面磁场、三维磁场；从最初的单自由度控制到多自由度控制；从最初的螺线管磁场发展到以永磁铁、电磁铁以及机械臂协同工作的外磁场驱动方式。然而，随着被控制的场景越趋复杂，传统磁场驱动方式也暴露出众多问题。例如：磁感应强度和磁场梯度不满足要求；磁控区域内的均匀度不够好；虽然可以实现多自由度控制，但是磁场的可操作空间比较狭小等等。本课题针对磁感应强度和磁场梯度不足，磁场控制区域的均匀度不高等问题开展研究。为建立新型的磁场控制策略，深入研究了磁场中磁介质的磁力与磁矩，建立了外部驱动电流与磁介质的磁力与磁矩的关系。并以螺线管磁场出发，提出了以螺线管为基础搭建磁场控制系统的计算方法，并且利用MATLAB软件仿真得到了八极螺线管磁场驱动矩阵。为了提高磁场强度和梯度，采用螺线管加铁芯的方式来汇聚磁感线。利用COMSOL有限元分析软件对带铁芯的电磁铁进行了系统的分析，得到了电流、螺线管分布、铁芯相对磁导率、铁芯形状对空间磁场分布的影响。针对磁场不均匀的问题，提出了利用梯度峰值的特性来解决，并将具有成对空心铁芯的电磁铁与亥姆霍兹线圈和麦克斯韦线圈对比，发现成对铁芯的电磁铁在保证磁场均匀的同时，又可以提高磁感应强度和梯度。根据空心铁芯电磁铁形成梯度峰值的性质，设计了平面磁场控制系统，并且加以验证。利用成对铁芯代替空心铁芯设计电磁铁的方法，设计了三维磁场控制系统，对三维磁场驱动系统进行了验证。根据三维磁控系统的需求，完成了磁控系统的硬件平台的设计与加工。设计的电源驱动系统由上位机、控制板和功率放大模块组成，用于驱动磁控系统。

As an important branch of robotics, microrobot has gained wide attention in many fields because it can carry out special operations in a narrow environment and overcome the size limitation. Among the numerous propulsion strategies of microrobot, the magnetic actuation has received great attention from researchers at home and abroad due to its superior performance in propulsion efficiency, the abundance of magnetic material, biological compatibility, medical safety, and other aspects. The magnetic actuation has progressed from the original uniform magnetic field and gradient magnetic field to the combined 2D magnetic field and three-dimensional magnetic field; from the original single degree of freedom control to multiple degrees of freedom control; from the original solenoid magnetic field to a magnetic field driven by the synchronized operation of permanent magnets, electromagnets, and robotic arms. However, there are still many limitations in the magnetic actuation, such as the magnetic flux intensity and magnetic gradient does not meet the requirements; the uniformity in the working area is not good enough. Although it can realize the multi-degree of freedom control, the magnetic control is only appliable to a narrow space.This paper aims to solve the problems of insufficient magnetic flux intensity and magnetic gradient and insufficient uniformity of the control area. To study the strategy of magnetic actuation, the force and torque of magnetic material are studied, and the relationship between current and force and torque of magnetic material is established. Based on the solenoid magnetic field, a method to calculate the solenoid based magnetic field is derived. To improve the magnetic field strength and gradient, solenoid and iron core are used to condense the magnetic flux lines. COMSOL is used to analyze the electromagnet with iron core, and the influences of current, solenoid distribution, relative magnetic conductivity of iron core and shape of iron core on the magnetic field distribution are obtained. In order to solve the problem of uneven magnetic field, the characteristic of gradient peak point is found, and the paired electromagnets is compared with Helmholtz coils and Maxwell coils. According to the property of gradient peak point of hollow core electromagnet, a planar magnetic field control system is designed and verified. A 3d magnetic field control system is designed by replacing a hollow core with a pair of cores. According to the requirements of 3d magnetic control system, the hardware of the magnetic control system is designed and fabricated. A power control system is designed, which is composed of upper computer, lower computer and power amplifier module to provide enough energy for electromagnet.

微机器人 磁场驱动系统 空心铁芯 梯度峰值 均匀磁场

microrobots magnetic control system electromagnets gradient field uniform magnetic field

中文

联合培养

南方科技大学

贾延超. 面向磁性微机器人的三维磁场驱动系统的研究[D]. 深圳. 哈尔滨工业大学,2020.