Clinical and mechanical studies progress on treatment of malignant tumour by ultralow frequency pulsed - gradient magnetic fields 半梯度磁場(chǎng)治療惡性腫瘤的臨床和機(jī)理研究進(jìn)展
But can keep even gradient magnetic field range strong , hall ' s component can only measurement displacement among a small circle ( usually only about 1mm ) 然而,能保持均勻梯度磁場(chǎng)的范圍不大,霍爾元件只能小范圍(通常僅約1mm )的測(cè)量位移。
The hore component is set on the tracking mechanical system to detect the magnetic field ' s movement . under this situation , the hore component will always keep up with the target ' s movement and keep in the magnet ' s unitary gradient magnetic field 這樣,霍爾元件慣性小、非接觸的優(yōu)點(diǎn)將使它在各種位移與振動(dòng)的測(cè)量中發(fā)揮作用,成為一種性能優(yōu)良的位移傳感器。
According to more effect , when the hore component is placed in a gradient field , at the same time the direction of the current is perpendicular to the direction of the voltage , then between the two parallel side face come out the hore voltage . when hore component is set in this kind of uni - gradient magnetic field and the electric current is unchanged , the voltage output of hore component will be proportional to the position of the hore component in the magnetic field . so we can use the hore component to measure the movement of hore component against magnetic field 根據(jù)霍爾效應(yīng)可知,置于磁場(chǎng)中的霍爾元件若電流方向與磁場(chǎng)方向垂直,則在霍爾元件垂直于磁場(chǎng)和電流方向的兩個(gè)側(cè)面將產(chǎn)生電勢(shì),將霍爾元件置于強(qiáng)度隨空間位置線性變化的磁場(chǎng)中,且控制電流恒定,輸出就正比于霍爾元件處于磁場(chǎng)中的位置,因此可以用霍爾元件來測(cè)量磁場(chǎng)與霍爾元件間的相對(duì)位移量。
If we want to compose in a larger area a uni - gradient magnetic field , the device will be too complicated and unfit for move . it will restrict the application of hore component in displacement measuring . in order to change this situation , in this dissertation , a kind of auto - tracking measuring system is introduced 若能在簡(jiǎn)單磁場(chǎng)的條件下,通過自動(dòng)跟隨系統(tǒng)驅(qū)動(dòng)霍爾元件跟隨測(cè)量移動(dòng)物體的位移,使霍爾元件盡可能地保持在均勻梯度磁場(chǎng)內(nèi),就可以在很大程度上增加測(cè)量范圍。
This paper presents our research in actuating in - vivo micro - robot based on the capsule endoscope platform by the external power . while seeking secure driving method we take several factors into account , such as driving environment , power transmitting and consuming , motion requirement and controllability , and locating technique . we mainly deal with driving the capsule with spatial gradient magnetic field , so we employ combined electro - magnetic coils , including gradient coils and homogenous coils , which have rotational dof around a translatable patient bed , to compose a controllable uniform gradient which act on the permanent - magnet embedded robot , thereby get an appropriate spatial force and torque to fulfill the anticipant locomotion such as move , stop , pitch and yaw 基于驅(qū)動(dòng)環(huán)境、能量供給和消耗、驅(qū)動(dòng)動(dòng)作要求及驅(qū)動(dòng)安全性與可控性,定位方案等多方面考慮,尋求安全可靠的腸胃檢查微機(jī)器人的外部驅(qū)動(dòng)控制方法,并著重研究直接利用外磁場(chǎng)磁力驅(qū)動(dòng)微機(jī)器人:在微機(jī)器人內(nèi)部嵌入永磁性體,利用體外的組合電磁線圈產(chǎn)生加載電流控制的驅(qū)動(dòng)磁場(chǎng),其中外部的電磁線圈由多組梯度線圈和勻場(chǎng)線圈組合構(gòu)成,通過繞病床的旋轉(zhuǎn)以及病床的平移共同控制微機(jī)器人所在位置的磁場(chǎng)強(qiáng)度及梯度,作用于微機(jī)器人內(nèi)嵌磁體以獲得空間意義上的必要驅(qū)動(dòng)力和調(diào)整轉(zhuǎn)矩,從而有效地完成驅(qū)動(dòng)動(dòng)作要求。