CN100435713C - External magnetic field driving system of in vivo microrobot - Google Patents

Abstract

The present invention discloses a driving system of an outer magnetic field for an in vivo microrobot. The present invention comprises a robot, and a built-in magnetic substance (1), a processing center (2), a diagnosis and treatment manipulator (3) and an outer driving device (4) of the robot. A uniform gradient magnetic field is formed by an assembly coil system in the space meaning. The size and the direction of the gradient are commonly controlled by adjusting the relative motions of loading current and part coil on human bodies, the built-in magnetic substance which acts on the robot obtains the expected space vectorial force, and thus, the expected motion is realized. The traveling of the outer magnetic field is independent of the friction between the microrobot and tissues of the human bodies. The uniform gradient avoids the abrupt change of the stress due to the displacement of the microrobot under the action of the magnetic field. The provided driving system has good safety and controllability, which provides basis for further researching a gradient magnetic field driving the microrobots of cavity tubes in the human body.

Description

The external magnetic field drive system of Micro-Robot in a kind of body

Affiliated field the present invention relates to the medical apparatus and instruments automatic field, the system that the gradient magnetic control that particularly a kind of externally built-up coil produces drives intracoelomic cavity pipe Micro-Robot down.

Technical background is along with the development of MEMS technology, and people wish to utilize Micro-Robot to enter human body to carry out noinvasive or Wicresoft's diagnosis and treatment.Wired system is more suitable for nearly table of body or short stroke occasion because lead leads and disturbs.For ease of particularly gastral traversal inspection of intracoelomic cavity pipe and operation, people study wireless mode.The wireless capsule scope is the digestive tract examining equipment that developed recently gets up, its basic feature is the digestive tract image that wireless transmission is taken with the little photographic head of capsule, and its representative products is the M2A and the breadboard Norika series of Japanese RF System of Israel Given Imaging company.

With the wireless capsule scope is that platform is set up micro Manipulator System in the body, can realize that digestive tract environment such as temperature, pH value detect, but dispenser, sampling, and adding behind the micromanipulator can be voluntarily or auxiliaryly finish particular procedure, and very vast potential for future development is arranged.

These capsule endoscope products all utilize digestive tract to wriggle naturally and travel through whole inspection area at present, and expectation is finally discharged with Excreta.But gastral peristalsis is very limited to the progradation of capsule endoscope, and whole checking process is slow and uncontrollable, and for example the review time of M2A reaches 8 hours, and loss is also quite high, can incarceration take place in addition and is detained human body.These deficiencies have restricted the scope of application, treatment effect and the function expansion of capsule endoscope, therefore are necessary the drive environment in conjunction with robot, add to drive control safely and effectively on existing basis.

Move the active traversal that driving realizes Micro-Robot in the body, its quantity of motion is big, energy consumption is high, thereby is different from the microoperation driving that realizes functions such as operation.Microoperation can drive functional material by the integrated exciting bank of body, perhaps utilizes the integrated electromagnetic driving system of body to realize.Because the tortuous complexity of digestive tract, surperficial stick-slip, many grooves and pleat, therefore not ideal for the multiple macroscopic view that realizes traveling through in the body, complexity and heavy motion with upper type.The huge consumption that move to drive makes proper year energy or wireless energy supply can't satisfy Micro-Robot and finishes other functions, as takes pictures or make a video recording, driving, image transmission and even dispenser, gets the total energy demand of biopsy, operation etc.Therefore be necessary to seek the external drive mode to reduce the body energy consumption.

Directly utilize outer field excitation can effectively reduce Micro-Robot body energy consumption.The Micro-Robot that people such as the Toshio Fukuda of Japan Nagoya university make utilizes the magnetostriction alloy mechanism under the external magnetic field driving to realize creeping in the microchannel.But the outfield exiting form is single, relies on the material deformation due to the outfield to be difficult to finish multiple action request merely.

External magnetic field is strong and two kinds of effects of torque to magnetic bodies, and it is in fact more simple and effective to utilize this direct magnetic force or torque to drive, and has significantly reduced Micro-Robot body energy consumption.In addition, the microoperation of robot can separate and the influence of a driving magnetic field outside not being subjected to mobile the driving as sampling, spray medicine, lens focus adjusting etc.

People such as the M.Sendoh of northeastern Japan university propose to utilize similar three Helmholtz coils that space rotating magnetic field is provided, and the control loading current acts on the embedded magnet of capsule to adjust magnitude of field intensity and direction, precession under capsule surface spiral lamination promotes.The Norika3 capsule can axially rotate, and its built-in electromagnetic coil provides rotating excitation field by overcoat that the person under inspection wears.But its Rotation Design is in order to increase the visual field to reduce omission, because the outfield direction of rotation is single and inhomogeneous, to drive poor effect when being converted to precession.

In fact precession mode has certain defective: spiral lamination makes swallows, discharges inconvenience and may cause damage when peristalsis of the digest tract; Digestive tract mostly is long tube-like thin-wall, many grooves, pleat, and precession may make digestive tract partly reverse to cause pain or damage; Each section of digestive tract diameter differs, and is also different with the capsule contact condition, and digestive tract content residue may be clogged thread pitch simultaneously, therefore is difficult to guarantee the efficient of precession.

Therefore we propose directly to utilize the outfield magnetically-actuated.The mobile driving that utilizes main body mechanism to carry out mostly, as creeping motion type, wheeled, crawler type, impact type, screw type etc., must rely on and subject between friction advance.Wish to reduce this friction when utilizing direct magnetic force, this is consistent with the security consideration that drives.Need not the integrated actuating mechanism of body and make that also the robot architecture obtains simplifying.Adopt medicine to suppress the part peristalsis of the digest tract when digestive tract examining and operation, and guarantee that Micro-Robot contact surface good lubrication will help driving.Driving should avoid causing tissue injurys such as mucosa as far as possible; Owing to have various disturbances such as peristalsis of the digest tract, sneeze, cough, have the hiccups etc., the person under inspection also can move naturally as slightly moving Micro-Robot opposing disturbance better performances when this requires the outfield to drive in addition.

The gradient of general externally-applied magnetic field sharply changes with operating distance, and the micro-displacement of robot also may cause stressed sudden change, makes location, control and security performance worsen, even " sneeze is decreased the ring intestinal wall ".The torque in magnetic field is very important in addition, and the big twisting resistance that is subjected in the driving process is a potential danger.

The gradient tensor of the suffered magnetic force of robot and externally-applied magnetic field and the intensity of magnetization of embedded magnetic are relevant, suffered magnetic torque relevant with the intensity of magnetization of field intensity and embedded magnet (formula 1).If embedded magnetic permanent magnet, then the intensity of magnetization can be considered constant, at this moment can rely on the suitable external magnetic field environment of structure to drive fully.

The driving of robot promptly will be constructed suitable space magnetic field and be distributed, and utilizes built-up coil can obtain uniform magnetic field intensity or uniform magnetic field gradient.The simplest shim coil is a Helmholtz coil, and it is that a pair of radius is R, at a distance of L=R and collude electric current loop to electric current, can form axial magnetic field very uniformly, and its radial component can be ignored.The simplest gradient coil is that Maxwell is right, and its radius is R, apart $L=\sqrt{3}R,$ Logical reverse current, can form the center field intensity is zero uniform gradient, and axial gradient is about radial twice.Nonaxisymmetrical coil, for example the reasonable combination of square coil also can reach effect same.

The shim coil of practical application all has multiple different form and method for designing with gradient coil.For example gradient coil is similar to NMR (Nuclear Magnetic Resonance)-imaging (MRI) gradient coil, and its kind can be divided into two kinds of vertical and horizontal by the relative direction with main field.If the MRI main field be z to the field, then only need to consider to the effective g of imaging _Zb(b=x, y, z) component (formula 2).Coil distribution generally forms by the simulate ideal surface current, wherein g _ZzProduced by vertical gradient coil, it is right that the formation principle of its gradient is similar to Maxwell; g _Zx, g _ZyProduced by horizontal gradient loop, lead mostly is streamlined distribution or is made of discontinuous different electric current sections.Drive coil is formed by various forms of coil combination, and practical is cylinder coil and planar coil.The general built-up coil that adopts the cylinder form, each is organized coil and is layering, and can form comparatively compact structure.

In fact, horizontal gradient loop does not produce transverse gradients merely, and vertically gradient coil does not produce vertical gradient merely yet; Different with MRI, when the magneticaction of compute gradient coil, need omnirange to consider the contribution of each component of gradient tensor.

Owing to there is not so-called main field when driving, be the used coil of difference MRI, we press drive coil and divide with respect to the direction of human body (or saying sick bed) longitudinal axis: mainly provide the magnetic field intensity of human body (sick bed) y direction or the coil of magnetic field gradient to be called axial coil, mainly provide perpendicular to the magnetic field intensity of human body (sick bed) y direction or the coil of magnetic field gradient to be called radial coil.

Gradient coil constructs more uniform gradient fields in the certain space scope, in this scope, under the same loading current, the suffered magnetic force of magnetic Micro-Robot has nothing to do with its position basically, so just can resist bigger disturbance; By changing the loading current of gradient coil, we can obtain the gradient of different size and Orientations, affact the magnetic force that just obtains different size and Orientations in the robot.But because gradient coil changes in the field intensity direction of diverse location, institute's torque suspension can change during the robot motion, can cause the non-hope of robot to be reversed under enough big situation, and then makes the stressed change of robot.Guarantee the two kinds of schemes that do not twist when the robot location changes: one provides the space relative translation degree of freedom between coil system and the examinee, makes robot be positioned at low place all the time; The 2nd, utilize shim coil to make the skew of low place and initiatively follow robot, even directly adjust field intensity make it with the intensity of magnetization of robot embedded magnet in the same way.

The drive coil zone of action is considered as passive region, and different gradient coils can produce different Distribution of Magnetic Field, but after the contribution of the magnetic field of synthetic each gradient coil, still has big dependency between each component of magnetic field gradient tensor.Need omnirange to consider the contribution of each component of gradient tensor owing to calculate magneticaction, these components can be subdued each other to the contribution of magnetic force under a lot of situations, therefore adopt different coil combination and loading current adjustment thereof in the hope of obtaining the method poor effect of any direction magnetic force fully.We utilize the mechanism kinematic of coil and gradient coil magnetic field to obtain to advance driving force for this reason, utilize the mechanism kinematic of sick bed and the field intensity size that shim coil is adjusted the robot position jointly, thereby adjust the suffered magnetic torque of robot.Like this, under magnetic force of determining and magnetic torque effect, the motion of robot can be controlled preferably.

The present capsule endoscope of summary of the invention relies on peristalsis to advance in digestive tract fully, there is not safe and practical active wireless driving method, uncontrollability has restricted the scope of application and the result of use of capsule endoscope, make with similar wireless endoscope to be platform, the technological expansion of diagnosis and treatment Micro-Robot can't realize in multi-functional body.

The objective of the invention is to design a kind of Micro-Robot external magnetic field drive system that intracoelomic cavity pipe traversal is checked that can be used for, utilize the magnetic field environment that built-up coil structure gradient is even, the spatial point field intensity is adjustable, and adjust magnetic field by the corresponding sports that changes coil loading current and coil and sick bed, act on the embedded magnet of Micro-Robot to reach the purpose of Micro-Robot in the control volume externally, realize that for final the wireless controlled diagnosis and treatment of Micro-Robot lay the foundation in the body.

Technical scheme of the present invention is:

The magnetic field that Micro-Robot external magnetic field drive system relies on external device (ED) to constitute in the body contactlessly acts on the interior Micro-Robot of body and drives with realization, and whole system comprises magnetic Micro-Robot, processing center, operation of diagnosis and treatment device and the external driver device that contains embedded magnet.

The shell of described magnetic Micro-Robot is made into capsule shape, the two ends slyness, middle no projection and groove, do not form the edge angle, adopt on the surface, and medical material slick, that have certain toughness and flexibility coats, friction to tissue is less, does not cause injury of human when active exercise and peristalsis of the digest tract, part such as the embedded magnetic of Micro-Robot internal integration, image collection module, internal microprocessor, wireless communication module (part that other and native system have nothing to do is at row).

Described embedded magnetic has definite intensity of magnetization M, as shown in Equation (1), it externally drives Micro-Robot under the effect in magnetic field, wherein, externally driving the Micro-Robot body due to the magnetic field gradient under the magneticaction advances, externally the magnetic torque effect drives the Micro-Robot tilted deflecting down to adjust attitude due to the magnetic field intensity, strengthen the stability that Micro-Robot is advanced simultaneously, described image collection module, internal microprocessor, wireless communication module is electrically connected by flexible PCB, the digestive tract environment image that photographic head in the image collection module photographs, be used to read by internal microprocessor, buffer memory, and control wireless communication module transmitted image information is to outside processing center, necessary timesharing control is realized at the associated treatment center simultaneously, to reduce outer driving coil to the Micro-Robot internal electromagnetic, the interference of circuit module.

Between the center of gravity of described Micro-Robot and its magneticaction point certain offset distance is arranged, magnetic force that applies when external magnetic field and the suffered gravity of Micro-Robot is not in the same way the time, thereby magnetic force provides certain moment that the attitude of Micro-Robot is adjusted, the auxiliary stability of carrying out the attitude adjustment and strengthening driving of the magnetic torque of utilizing external magnetic field to apply simultaneously.

In addition, in the described Micro-Robot, the effective object of external magnetic field is embedded magnetic, drive any structure feature that does not rely on Micro-Robot itself, embedded magnetic adopts permanent magnet or the little coil of electromagnetism, wherein when adopting the little coil of electromagnetism of one or more direction configurations, the loading current that changes little coil is equivalent to loading current variation or external agency's motion of external magnetic field to a certain extent, carries the energy or wireless energy supply but need consume body with the little coil of electromagnetism.

Described processing center is responsible for the switch of whole system, initialization and overall the driving are controlled, it comprises central processing unit and peripheral hardware equipment, software program, peripheral hardware equipment comprises data acquisition equipment (reception antenna and pick off), memory device, display device, input terminal, various data and signal line and interface, it connects the Micro-Robot position detecting device, the motion actuating unit, coil power and operation of diagnosis and treatment device, receive picture signal, the Micro-Robot position detection signal, coil movement and current feedback, bed motion feedback and operation of diagnosis and treatment device control signal generate coil current and load, coil rotatablely moves and the control signal of bed motion.

Described operation of diagnosis and treatment device comprises base, rudder stock, shift knob and slider, rudder stock can be done the secondary rotation of ball, slider can linearly be adjusted driving force and doubly be worth, the actuating signal that the operation of diagnosis and treatment device is used to indicate Micro-Robot deflection, pitching, stop and advancing etc., adjustment to the driving force size is provided simultaneously, and its control signal is implemented in coil movement actuating unit and coil power by processing center.In addition, described operation of diagnosis and treatment device assembling magnetic torque effect switch, to whether adopting the auxiliary Micro-Robot attitude of adjusting of magnetic torque to set, described bed motion executor stops the automatic control by processing center during switch open, and provide the control signal of bed motion to import by the treated center of operation of diagnosis and treatment device, other assembles emergency switch, in emergency circumstances cuts off coil power immediately, closes driving magnetic field and causes safety hazard with the incident of preventing an accident.

Described Micro-Robot position detecting device is made by Magnetic Sensor, detect the vector position information and the attitude information of Micro-Robot when driving, offer processing center, position-measurement device is by magnetoresistive transducer, or Hall element is made, calculate the spatial positional information of embedded magnet and the direction vector of intensity of magnetization M thereof by the processing center processing, to realize the control of position and attitude, its detection scheme comprises two kinds:

1. inner detection mode: position detecting device adopts three-dimensional Magnetic Sensor, be incorporated into Micro-Robot inside, position relative fixed between pick off and the embedded magnet, embedded magnet is constant to the magnetic field contribution at sensor measurement place, sensor external coil magnetic field, gather dynamic field intensity signal and come out by the wireless communication module wireless transmit, the uniform gradient feature of known external magnetic field has been set up the strong linear relationship between magnetic field intensity and the locus, and therefore the magnetic field intensity information that is obtained by detection obtains the Micro-Robot spatial positional information easily.

2. external detection mode: position detecting device adopts array of magnetic sensors, be distributed in sick bed or examinee's body surface, externally driving magnetic field weakens the variation of gap detection robot embedded magnet vector field intensity value, obtain the Distribution of Magnetic Field information of the embedded magnet of Micro-Robot, calculate the polarised direction and the position of magnetic pole of the embedded magnet of Micro-Robot according to dipole model of magnetic, because embedded magnet is consolidated in the Micro-Robot body, polarised direction and position of magnetic pole can directly be converted to the positional information of Micro-Robot.

Wherein, in view of first kind of position probing scheme can not be isolated to the formed characteristic magnetic field of native system external coil, the invention is intended to comprise rights protection requirement to this position probing scheme.

Described sick bed is non magnetic sick bed, and is slightly wideer than human body shoulder, and sick bed is not influenced by driving magnetic field yet and driving magnetic field do not produced interference, and the examinee couches on this sick bed, and sick bed can be pushed to the drive coil active region with the examinee along its longitudinal axis translation.

Described drive wire corral cover inspection person is examined the position, and external drive magnetic field is provided, and coil surface attaches Hall element to obtain the loading current signal feedback.Drive coil provides electric current to load by coil power, and as the description of formula, the magnetic field environment of its structure and its loading current are broadly linear.Drive coil is by axial gradient coil, gradient coil and axially three kinds of coils of shim coil set are stacked constitutes, the similar MRI coil of its manufacture method (comprising gradient coil and radio-frequency coil), the filling insulating barrier is so that not conducting and reinforcing each other, the lamination order no requirement (NR), three kinds of coils are made of one, under the coil motion actuators drives, rotate, or make isolating construction, wherein can rotate with respect to the symmetric coil of sick bed axis shaft around sick bed longitudinal axis integral body.Described gradient coil, be respectively applied for and provide sick bed axially and gradient; Described shim coil set provides the component of the field intensity on the shaft section, is used to adjust the radially field intensity of robot position.In addition, can not use shim coil in the described drive coil, λ=0 in formula this moment (7), the adjustment of magnetic torque relies between sick bed and the drive coil relative translation at three-dimensional fully, the variation of p is just finished, and stability that drive this moment and controllability reduce, for the auxiliary adjustment capability reduction of Micro-Robot attitude, and, make the volume of coil increase because D translation requires the more freedom space.

Described motion actuating unit comprises coil movement executor and bed motion executor, and drive coil is by stent support, and is accurately rotated around sick bed by the coil movement actuator driven, and its value is with the tolerance of the γ in formula (4); Sick bed is by stent support, utilize the kinds of drive such as leading screw, along the accurate translation of self axis, its value is the component of p on the sick bed axis in the formula (5) by the bed motion actuator driven, and wherein bed motion executor's translational motion can directly be controlled by processing center automatically.The driving magnetic field environment is controlled in the loading current adjustment of above mechanism kinematic coordinated drive coil jointly.

Described coil power under the control of processing center, can carry out that the multichannel electric current loads and the adjustment of real-time current value, and from invest on the coil Hall element or the current signal feedback.The vectorial I of its loading current value in the formula (5) _GWith I _BExpression.

Described coil brace and sick bed support are fixed in ground, difference support coils and sick bed, and the motion actuating unit is installed on the support.

Driving magnetic field acts on the magnetic Micro-Robot that contains embedded magnet, Micro-Robot is moved under the direct force of controlled gradient magnetic and moment loading, under magnetic field control, can finish effectively advance, stop, action requests such as pitching, deflection, thereby can locate the emphasis section and suspect that section carries out scrutiny and treatment to the examinee.

Correlation formula:

$F={\∫}_V(M\·\▿)\mathrm{Bdv},T={\∫}_{V}M\×\mathrm{Bdv}$

$\⇒F=\mathrm{VG}\·M,T=\mathrm{VM}\×B---\left(1\right)$

$G=\left[\begin{array}{ccc}{g}_{\mathrm{xx}}& g_{\mathrm{xy}}& g_{\mathrm{xz}}\\ g_{\mathrm{yx}}& g_{\mathrm{yy}}& g_{\mathrm{yz}}\\ g_{\mathrm{zx}}& g_{\mathrm{zy}}& g_{\mathrm{zz}}\end{array}\right](g_{\mathrm{ab}}=\frac{\∂B_a}{\∂b};a,b=x,y,z)---\left(2\right)$

$\▿\·B=0,\▿\×B=0$

$\⇒g_{\mathrm{xx}}+g_{\mathrm{yy}}+g_{\mathrm{zz}}=0,g_{\mathrm{ab}}=g_{\mathrm{ba}},(a\≠b)---\left(3\right)$

$C=\left[\begin{array}{ccc}1& 0& 0\\ 0& \cos \mathrm{\γ}& \sin \mathrm{\γ}\\ 0& -\sin \mathrm{\γ}& \cos \mathrm{\γ}\end{array}\right]---\left(4\right)$

G＝кI _G；B＝Gp+λI _B (5)

VкI(C ^TM)＝C ^TF (6)

VM×[C(кI _Gp+λI _B)]＝T (7)

Formula (1) wherein: the action of a magnetic field power and torque formula, wherein F is a magnetic force; T is a magnetic torque; V is embedded magnet volume; M is the intensity of magnetization of embedded magnet; B is an external magnetic field magnetic induction; Less in this formula owing to the embedded magnet of robot, thereby suppose that field intensity and gradient thereof are at the robot interior uniform distribution;

(2): G is the magnetic field gradient tensor, a in the formula, and b gets x, y, arbitrary value among the z, this drive system promptly obtains suitable G by built-up coil and relative motion thereof, produces suitable driving force thereby act on the embedded magnet of Micro-Robot;

(3): only consider outer driving coil magnetic field, obtain each component of coil magnetic field gradient tensor according to Maxwell magnetostatic field equation high correlation is arranged, this dependency of being represented by this formula causes static coil to be difficult to obtain the magnetic force of any direction, therefore we have designed the drive scheme of the relative human body of coil (sick bed) motion, consider organization of human body, this motion is designed to rotate around human body (sick bed);

(4): coil is around the spin matrix of human body (sick bed) rotation, and wherein γ is the anglec of rotation, and its rotating shaft is along the sick bed axis, sets with clockwise for just;

(5): with the magnetic field descriptive equation of loading current phase relation, wherein p is the position vector that the position P of robot leaves the drive coil center; G is the gradient tensor sum that each coil is ordered at P; B is the magnetic induction at P point place; к, λ are respectively the constant with gradient coil and shim coil self parameter correlation, and wherein к is three rank constant matricess, and λ is a constant vector; I _GWith I _BBe respectively the vector of the each several part loading current composition of gradient coil and shim coil;

(6):, show available spin matrix C and gradient coil loading current I with the magnetic force descriptive equation of loading current phase relation _GControl magnetic force size.

(7): with the magnetic torque descriptive equation of loading current phase relation, this formula shows available spin matrix C, sick bed translation (influencing p) and gradient coil loading current I for each coil is made of one the situation of common rotation _GControl magnetic torque size.

The invention has the beneficial effects as follows:

1, by with combination such as magnetic field technique, sensing technology, image technique, electric power technology and be applied to noinvasive diagnosis and treatment field, drives control with the external wireless that realizes Micro-Robot in the body;

2, active drive has been reduced the inspection required time, and has reduced loss, makes diagnosis and treatment convenient and efficient.

3, the uniform gradient field that produces of gradient coil makes drive system can resist big disturbance, and the field intensity of shim coil is adjustable whole robot position is reversed thereby suppress its non-hope, has improved driving safety and reliability.

Can initiatively reduce the power effect between robot and the subject when 4, utilizing direct magnetic force, check sense of discomfort to reduce;

5, Micro-Robot can be finished action requests such as translation, pitching, deflection effectively under the control of magnetic field, thereby can locate the emphasis section and suspect that section carries out scrutiny and treatment, has strengthened the effectiveness of its diagnosis and treatment;

6, can further expand the treatment function such as dispenser, sampling, operation of Micro-Robot, improve its diagnosis and treatment ability;

7, be not only applicable to body cavity of organism pipe ring border, be fit to interior driving of multiple nonmetal pipeline of various calibers yet, wider range of application is arranged.

Description of drawings

Below in conjunction with drawings and Examples patent of the present invention is described further.

Fig. 1 is that Helmholtz coil and Maxwell are to the magnetic signature sketch map.

Fig. 2 is an external drive system structure sketch map;

Fig. 3 is a driving device entity sketch map;

Fig. 4 is that drive coil 7 constitutes illustration;

Fig. 5 is other formation illustrations of drive coil;

Fig. 6 is the part nuclear magnetic resonance, NMR gradient coil sketch map of practical application.

Fig. 1 is that Helmholtz coil and Maxwell are to the magnetic signature sketch map.Helmholtz coil is that a pair of radius is R, at a distance of L=R and collude electric current loop to electric current, can form axial magnetic field very uniformly, and its radial component can be ignored.Maxwell is R to radius, apart $L=\sqrt{3}R,$ Logical reverse current can form the center field intensity and be zero uniform gradient, and axial gradient is about radial twice, and Maxwell is to only showing bright axial magnetic field B among the figure _z

Fig. 2 is an external drive system structure sketch map, and Fig. 3 is a driving device entity sketch map.

In conjunction with described Fig. 2 and Fig. 3, wherein 1: the magnetic Micro-Robot; 2: processing center; 3: the operation of diagnosis and treatment device; 4: external driver device; 5: robot location's checkout gear; 6: sick bed; 7: drive coil; 8: the motion actuating unit; 9: coil power; 10: coil brace; 11: the sick bed support; 12: digestive tract.

Described magnetic Micro-Robot 1 comprises parts such as embedded magnet a, wireless transmitter module b, internal microprocessor c, little photographing module d.

Described motion actuating unit 8 comprises 8a: coil movement executor; 8b: bed motion executor.

Fig. 4 is that drive coil 7 constitutes illustration.Described drive coil 7 comprises 7a: axial cylinder gradient coil; 7b: cylinder gradient coil radially; 7c: the cylinder shim coil set (birdcage coil) that horizontal field intensity is provided.Axially and radially axially dividing with respect to sick bed here is different from the statement of malcoils.

Fig. 5 is other formation illustrations of drive coil, is the axial symmetry coil among the figure, and wherein 2 pairs of the insides are that the multiwalled Maxwell of multiturn is right, and 2 pairs of outsides are the multiwalled Helmholtz coils of multiturn.

Fig. 6 is the part nuclear magnetic resonance, NMR gradient coil sketch map of practical application, is followed successively by horizontal cylinder gradient coil A, vertical cylinder gradient coil B, and transverse plane gradient coil C, fore-and-aft plane gradient coil D can be used as reference when drive coil designs.

The specific embodiment is in Fig. 2, and magnetic Micro-Robot 1, operation of diagnosis and treatment device 3 and external driver device 4 all link with processing center 2.Wherein magnetic Micro-Robot 1 is swallowed by the examinee, carry out wireless telecommunications with external treatment center 2 after entering digestive tract, operation of diagnosis and treatment device 3 is implemented control by motion actuating unit 8 in 2 pairs of external driver device 4 of processing center and coil power 9, and is finally carried out by sick bed 6, drive coil 7.

Micro-Robot 1 is made into capsule shape, the two ends slyness, middle no projection and groove, do not form the edge angle, adopt on the surface, and medical material slick, that have certain toughness and flexibility coats, friction to tissue is less, does not cause injury of human when active exercise and peristalsis of the digest tract, is fit to swallow, travels through digestive tract and final the drainage.

Part such as the embedded magnetic 1a of Micro-Robot internal integration, image collection module 1b, internal microprocessor 1c, wireless communication module 1d (part that other and native system have nothing to do is at row), wherein back three parts are actually one, and are electrically connected successively by flexible PCB.

Described embedded magnetic 1a is positioned at Micro-Robot middle part, adopts the NdFeB magnet to make, and cylindrically is filled in the flexible PCB gap, or is made into needle-like and is filled in gap between circuit board and the housing.Embedded magnetic 1a has definite intensity of magnetization M, it externally due to the magnetic field gradient magneticaction drive the Micro-Robot body down and advance, externally the magnetic torque effect drives the Micro-Robot tilted deflecting down to adjust attitude due to the magnetic field intensity, strengthens the stability that Micro-Robot is advanced simultaneously.In addition, in the described Micro-Robot 1, the effective object of external magnetic field is embedded magnetic 1a, drives any structure feature that does not rely on Micro-Robot itself.Embedded magnetic 1a also can adopt the little coil of electromagnetism of one or more direction configurations, the loading current that changes little coil is equivalent to loading current variation or external agency's motion of external magnetic field to a certain extent, carries the energy or wireless energy supply but need consume body with the little coil of electromagnetism.Described image collection module 1b is positioned at the head of Micro-Robot; its photographic head adopts CMOS or CCD; protect with translucent cover; translucent cover can be made amasthenic lens to take the near-end image; the digestive tract environment image information of taking by internal microprocessor 1c read, buffer memory, and be sent to outside processing center 2 by wireless communication module 1d.Necessary timesharing control is realized at microprocessor 1c associated treatment center 2, when driving to reduce external coil 7 to the interference of Micro-Robot internal electromagnetic, circuit module.Among the described wireless communication module 1d antenna element be around in the flexible PCB periphery, near Micro-Robot shell place.

Described processing center 2 is by computer workstation and relevant software and hardware structure, as the concentrated area of each data and signal, provide Micro-Robot in the medical care operator operating body with reference to the interface.

Described image information operation operation of diagnosis and treatment device 3, actuating signals such as deflection, pitching being provided, stopping and advancing also has magnetic torque effect switch, magnetic field emergency cut-off switch in addition.The auxiliary attitude adjustment instruction of the magnetic torque of operation of diagnosis and treatment device 3 has higher priority than the automatically low place adjustment instruction of processing center 2, when being necessary to utilize the auxiliary adjustment of magnetic torque effect robot pose, can opening magnetic torque effect switch and manually adjust shim coil set 7c loading current.

Described robot location's checkout gear 5 is by magnetoresistive transducer, or Hall element is made, and two kinds of detection schemes are arranged, and promptly detects external coil or the embedded magnet vector of detection machine people field intensity value.Information that detection obtains and known magnetic field spatial distribution are made comparisons, and handle and calculate the positional information of robot 1 and the direction vector of intensity of magnetization M thereof, offer processing center 2.When measuring embedded magnets magnetic fields mode, position detecting device 5 adopts array of magnetic sensors, be distributed in sick bed or examinee's body surface, externally driving magnetic field weakens the variation of gap detection robot embedded magnet vector field intensity value, the final Micro-Robot positional information that obtains, what represent among Fig. 2 is exactly this mode; Or with measuring the external coil magnetic approach, position detecting device 5 is made three-dimensional Magnetic Sensor, be incorporated into Micro-Robot 1 inside, position relative fixed between pick off and the embedded magnet, embedded magnet is constant to the magnetic field contribution at sensor measurement place, sensor external coil magnetic field, gather dynamic field intensity signal and come out by wireless communication module 1d wireless transmit, the uniform gradient feature of known external magnetic field has been set up the strong linear relationship between magnetic field intensity and the locus, and therefore the magnetic field intensity information that is obtained by detection obtains the Micro-Robot spatial positional information easily.

Described sick bed 6 is non magnetic sick bed, is driven coil 7 and coats, and along with the difference of drive coil form, sick bed 6 and drive coil 7 all have corresponding different motion form, and we are designed to the sick bed translation according to organization of human body at this.

Described drive coil 7 provides the external magnetic field, by gradient coil with shim coil set is stacked constitutes, obtains the loading current signal feedback by Hall element.Require to reduce each coil during design to the subduing mutually of Robot Force effect, coil power loads different electric currents by control requirements respectively to each group coil, obtains different magnetic field size and distribution.Current Control can be from each coil dress Hall element to obtain feedback.Suppose that coil space (can hold maximum column diameter) is 60cm, Micro-Robot gross weight 5 grams, embedded about 1.8g (246mm3) NdFeB magnet, its intensity of magnetization is 106A/m, the magnetic robot that then picks up these 5 grams needs the gradient of 0.2T/m at least, this will require to drive Micro-Robot and load big electric current, and therefore making and the coil power to coil has higher requirements.

In drive coil configuration example shown in Figure 4, three groups of coils all adopt the cylinder form, and structure is comparatively compact.Drive coil is with reference to the coil design among the MRI, and wherein the 7a gradient coil is positioned on the sick bed axial direction, and it mainly provides axial gradient, and it also has the gradient component simultaneously; The 7b gradient coil is positioned at sick bed in a lateral direction, and it mainly provides gradient, and it also has the axial gradient component simultaneously; 7c is the birdcage shim coil, and the field intensity on the shaft section is provided, and is used to adjust radially (with respect to the sick bed axis) field intensity component of robot position.Each organizes filling insulating barrier between the coil so that not conducting and reinforce the lamination order no requirement (NR) each other.Coil is optimized by various Technologies, obtains low-power consumption, high linearity, compactness and drive system efficiently.

In drive coil configuration example shown in Figure 5, three groups of coils all adopt the multiturn lattice coil of axially symmetric structure, and form is comparatively simple.In 4 groups of coils shown in the figure, the inside is a gradient coil for two groups, and the outside is a shim coil for two groups, and their function is identical with each the coil function described in Fig. 4, and its arrangement is to consider the ratio that will as far as possible increase coil space and winding volume in proper order.At least from inside to outside second group of gradient coil in these 4 groups of coils, promptly the gradient coil needs and can rotate around the sick bed axis.

Described motion actuating unit (8) comprises coil movement executor a and bed motion executor b, generally with motor as power.Drive coil is supported by support 10, and both are connected by lubricated good revolute pair, and all or part of coil accurately rotates around sick bed 6 under coil motion actuators 8a drives; Sick bed 6 is supported by support 11, and support 11 has two double-lengths of a body at least, can utilize the kinds of drive such as leading screw, is driven along the accurate translation of self axis by bed motion executor 8b.The adjustment of the collaborative 9 pairs of coil loading currents of coil power of these mechanism kinematics can obtain suitable driving magnetic field.Horizontal gradient loop 7b as described in Figure 4 rotatablely moves longitudinally around sick bed, cooperates the electric current of gradient coil overall 7 to load, and can obtain effective space magnetic field gradient, promptly obtains effective non-coplanar force; Shim coil set (7c), add the relative translation of sick bed (6), can obtain suitable space field intensity value in the Micro-Robot position, thereby obtain suitable magnetic torque, when not auxiliary attitude adjustment requires, dynamically adjust Micro-Robot (1) position for low place, adjust required particular field strength value otherwise be adjusted into attitude.Wherein the sick bed translation is used to adjust the longitudinal field strong component of robot position.

The particular exam process is: at first, Micro-Robot (1) is opened switch, and image acquiring device (1b), microprocessor (1c) and wireless communication apparatus (1d) are started working.Micro-Robot (1) is swallowed in the abdomen by the examinee, enters examinee's digestive tract (12), wireless image information of sending out digestive tract (12), and by the antenna reception of external treatment center (2), and treated center (2) handle the back at screen display.

The examinee couches on the non magnetic sick bed (6), and drive coil (7) loads initial current, forms uniform gradient magnetic field, this moment drive coil (7) inner space point magnetic field intensity and the coordinate amount linear correlation of this point.

Sick bed (6) obtains active position information along self axis translation up to position detecting device (5), sends system initialization commands by the medical care operator by processing center (2) then.With the difference of position probing mode, the acquiring way of amount of correlated information is distinguished to some extent:

1. during the external detection mode, position detecting device (5) and sick bed (6) fixed (or being affixed on examinee's body surface), directly detect the embedded magnet of Micro-Robot (1a) Distribution of Magnetic Field, obtain the positional information of Micro-Robot (1) with respect to sick bed (6), calculate the position relation of Micro-Robot (1) according to sick bed (6) with respect to the translational movement of drive coil (7) then, determine that further the external magnetic field of Micro-Robot (1) position distributes with respect to drive coil (7).

During 1. inner detection mode, position detecting device (5) is fixed with Micro-Robot (1), the external magnetic field of directly detecting Micro-Robot (1) position distributes, according to the magnetic field intensity of drive coil (7) inner space point and the linear relationship of this point coordinates amount, obtain the position relation of Micro-Robot (1) with respect to drive coil (7).

During initialization, processing center (2) is handled magnetic Micro-Robot (1) positional information that obtains, judge that Micro-Robot (1) is whether in the low place of drive coil (7), if not then it being adjusted to low place, self-regulating process is as follows: processing center (2) is sent instruction to bed motion executor (8b) and coil power (9), sick bed (6) continues to adjust along its axis translation, axial field intensity up to robot (1) position is zero (generally promptly being positioned at the axis of centres cross section of drive coil), adjust shim coil set (7c) loading current then, the radially field intensity that makes Micro-Robot (1) loca also is zero, Micro-Robot (1) is in the low place of drive coil (7) fully like this, so far system initialization finishes, and external driver device (4) prepares to drive operation.

When driving operation, medical personnel handle operation of diagnosis and treatment device (3) according to the digestive tract image information, different control actions such as provide deflection, pitching, advance, stop, be converted to loading current and telecontrol equipment control signal by processing center (2), send gradient coil (7a, 7b) electric current load instructions, send the instruction that rotatablely moves to coil movement executor (8a) to coil power (9).Gradient coil (7a, 7b) loading current change and the situation of Spin Control under produce the gradient fields of any direction in space, act on the power that embedded magnet (1a) then obtains direction in space, thereby realize deflection, pitching, action such as advance, stop.Generally speaking, automatically control collaborative Micro-Robot (1) position of adjusting of shim coil set (7c) and bed motion executor (8b) by processing center (2) and be low place, if the auxiliary requirement of adjusting attitude or improving stability is arranged, then open magnetic torque effect switch on the operation of diagnosis and treatment device (3) by the medical care operator, shim coil set (7c) loading current is controlled, adjust the field intensity of Micro-Robot (1) position, to obtain suitable magnetic torque.

Driving magnetic field acts on the magnetic Micro-Robot (1) that contains embedded magnet, Micro-Robot is moved under the direct force of controlled gradient magnetic and moment loading, under the control of magnetic field, can finish action requests such as translation, pitching, deflection effectively, thereby can locate the emphasis section and suspect that section carries out scrutiny and treatment to the examinee.

Obviously, those skilled in the art can comprise drive coil, sick bed and associated mechanisms motion thereof to drive system of the present invention, and robot location's detection means is carried out various changes and modification and do not broken away from the spirit and scope of the present invention.Like this, if of the present invention these are revised and modification belongs within the scope of claim of the present invention and equivalent technologies thereof, then the present invention also is intended to comprise these changes and modification interior.

Claims (1)

1, Micro-Robot external magnetic field drive system in a kind of body, the magnetic field that relies on external device (ED) to constitute contactlessly acts on the interior Micro-Robot of body to realize driving, and system comprises magnetic Micro-Robot (1), processing center (2), operation of diagnosis and treatment device (3) and the external driver device (4) of embedded magnet;

Described magnetic Micro-Robot (1) is made into the little capsule shape that does not cause injury of human when active exercise and the peristalsis of the digest tract of the friction of tissue, capsule surface adopts slick, have certain toughness and flexible medical material coating, Micro-Robot inside comprises embedded magnetic (1a), image collection module (1b), internal microprocessor (1c), wireless communication module (1d), wherein said embedded magnetic (1a) externally due to the magnetic field gradient magneticaction drive Micro-Robot (1) body down and advance, simultaneously externally due to the magnetic field intensity magnetic torque effect drive Micro-Robot (1) tilted deflecting down to adjust attitude, strengthen the stability that Micro-Robot (1) is advanced simultaneously, described image collection module (1b) adopts little photographic head, take image nearby, described internal microprocessor (1c) reads, buffer memory digestive tract image, control wireless communication module (1d) transmitted image information is to outside processing center (2), and associated treatment center (2) realization timesharing control, to reduce outer driving coil (7) to Micro-Robot (1) internal electromagnetic, the interference of circuit module;

Described processing center (2) is responsible for the switch of system, initialization and overall the driving are controlled, comprise central processing unit and peripheral hardware equipment, software program, described peripheral hardware equipment comprises reception antenna, memory device, display device, various data and signal line and interface, connect Micro-Robot position detecting device (5), motion actuating unit (8), coil power (9) and operation of diagnosis and treatment device (3), receive picture signal, the Micro-Robot position detection signal, coil movement and current feedback, bed motion feedback and operation of diagnosis and treatment device control signal generate coil current and load, coil rotatablely moves and the control signal of sick bed (6) motion;

Described operation of diagnosis and treatment device (3) is operated by the medical care operator, control Micro-Robot (1) deflection, pitching are provided, stop and the actuating signal of advancing, adjustment to the driving force size is provided simultaneously, and its control signal is implemented in coil movement actuating unit (8a) and coil power (9) by processing center (2);

Described external driver device (4) comprises Micro-Robot position detecting device (5), sick bed (6), drive coil (7), motion actuating unit (8), coil power (9), coil brace (10) and sick bed support (11), wherein:

Micro-Robot position detecting device (5) is made by Magnetic Sensor, detects the vector position information and the attitude information of Micro-Robot (1) when driving, and offers processing center (2);

Sick bed (6) does not produce interferential non magnetic sick bed to driving magnetic field for not influenced by driving magnetic field yet, and the examinee couches on this sick bed, and sick bed (6) can be pushed to the examinee active region of drive coil (7) along its longitudinal axis translation;

Drive coil (7) encloses and covers the examinee and examined the position, external drive magnetic field is provided, and by Hall element acquisition loading current signal feedback, described drive coil (7) comprises gradient coil (7a, 7b) and shim coil set (7c), and wherein said gradient coil (7a, 7b) is used to provide sick bed axial and gradient; Described shim coil set (7c) provides the component of the field intensity on the shaft section, is used to adjust the radially field intensity of robot position;

Drive coil (7) is by axial gradient coil (7a), gradient coil (7b) and axial three kinds of stacked formations of coil of shim coil set (7c), not conducting each other, the lamination order no requirement (NR), three kinds of coils are made of one, under driving, rotates coil motion actuators (8a) around sick bed longitudinal axis integral body, or three kinds of coils are made isolating construction, gradient coil (7b) or add other coil of top and rotate only around the sick bed longitudinal axis, when not using shim coil, then the adjustment of magnetic torque relies between sick bed (6) and the drive coil (7) relative translation at three-dimensional fully;

Motion actuating unit (8) comprises coil movement executor (8a) and bed motion executor (8b), and drive coil (7) is supported by support (10), and by coil movement executor (8a) driving and around accurately rotation of sick bed (6); Sick bed (6) is supported by support (11), utilize the lead screw transmission mode, drive along the accurate translation of self axis by bed motion executor (8b), wherein directly by processing center (2) control automatically, the driving magnetic field environment is controlled in the loading current adjustment of above mechanism kinematic coordinated drive coil (7) jointly in bed motion executor's (8b) translational motion;

Coil power (9) under the control of processing center (2), can carry out the multichannel electric current and load and the adjustment of real-time current value, and the current signal that obtains from the Hall element that invests on the coil feeds back;

Coil brace (10) and sick bed support (11) are fixed in ground, difference support drive coil (7) and sick bed (6), and motion actuating unit (8) is installed on the sick bed support (11);

Driving magnetic field acts on the magnetic Micro-Robot (1) that contains embedded magnet, Micro-Robot (1) is moved under the direct force of controlled gradient magnetic and moment loading, under magnetic field control, can finish advance, stop, pitching, deflection action requirement, thereby can locate the emphasis section and suspect that section checks the examinee and treat;

Described Micro-Robot (1) inside comprises embedded magnetic (1a), adopt permanent magnet or the little coil of electromagnetism, when adopting the little coil of electromagnetism of one or more direction configurations, the loading current that changes little coil is equivalent to loading current variation or external agency's motion of external magnetic field to a certain extent, it is characterized in that:

Described operation of diagnosis and treatment device (3) assembling magnetic torque effect switch, to whether adopting auxiliary Micro-Robot (1) attitude of adjusting of magnetic torque to set, described bed motion executor (8a) stops the automatic control to processing center (2) during switch open, the control signal input of bed motion is provided by the treated center of operation of diagnosis and treatment device (3) (2), operation of diagnosis and treatment device (3) assembling emergency switch, in emergency circumstances cut off coil power immediately, close driving magnetic field and cause safety hazard with the incident of preventing an accident;

Described robot location's measuring device (5) is by magnetoresistive transducer, or Hall element is made, calculate the spatial positional information of embedded magnet (1a) and the direction vector of intensity of magnetization M thereof by processing center (2) processing, to realize the control of position and attitude, its detection scheme is to detect external coil magnetic field or the embedded magnet vector of detection machine people field intensity value;

Described detection external coil magnetic field is: position detecting device (5) adopts three-dimensional Magnetic Sensor, be incorporated into Micro-Robot (1) inside, detect external coil magnetic field, gather dynamic field intensity signal and come out by wireless communication module (1d) wireless transmit, magnetic field intensity of setting up according to the uniform gradient feature of external magnetic field and the strong linear relationship between the locus, the spatial positional information of the magnetic field intensity information acquisition Micro-Robot (1) that obtains by detection;

The embedded magnet vector of described detection machine people field intensity value is: position detecting device (5) adopts array of magnetic sensors, be distributed in sick bed (6) or examinee's body surface, the variation of the embedded magnet vector of detection machine people (1) field intensity value, the positional information of acquisition Micro-Robot (1).

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