Chain for transmitting movement between actuators and the base of a member for driving a movable element

Disclosed is a movement transmission chain including: a base of a driving member for driving a movable element; and three actuators controlling the base of the driving member in three movement directions orthogonal to one another, by element of three interfaces with the base of the driving member, the mid-surfaces of the three interfaces intersecting in a central region of the base of the driving member.

The present invention relates to the chains for transmission of movement between several actuators and a drive member for a mobile element. The mobile element can in particular be a catheter or a catheter guide, but not necessarily.

The manual insertion of a catheter or a guide in a patient is a relatively conventional surgical procedure. However, since this procedure is monitored by x-rays, the surgeon in charge of this procedure is subject to significant irradiation if the surgeon does such an operation on many patients.

In order to reduce the risks for the surgeon, it is attempted to make such an insertion robotic. Making it robotic is complex because it is difficult to grasp the catheter. The catheter is in fact bathed in storage liquid and must remain sterile. Further, it is desirable to be able to command movements of translation and alternating and/or simultaneous rotation of the catheter. The reliability of these robotic systems is a decisive criterion.

In robotic modules from the prior art, whether in the medical field of catheters or in other fields, the actuators, which transmit the movement thereof to the drive member, transmit it by means of respective interfaces between the respective actuators and the base of the drive member.

Hence, in these robotic modules in the prior art, the interfaces are located outside of the base of the drive member or in the peripheral region of the base of the drive member.

The implementation structure of these interfaces between actuators and drive member base is then relatively simple.

The invention has however detected a problem of reliability for the transmission of the movement between actuators and drive member base in that case.

In fact, the invention has shown that this reliability problem comes from the off-center nature of the position of the interfaces, then driving in imbalanced transmission of the force.

Further, each actuator only supports the force in the direction thereof, there is nothing to carry one or more other actuators in one or more other directions, as could be the case in existing systems: the bulk and weight are sharply reduced that way.

This is why, the invention proposes to arrange the interfaces such that the intersection thereof is located in a central region of the base of the drive member, even preferably at the center of gravity of the base of the drive member, then allowing a balanced transmission of the force, driving a reliable transmission of movement between actuators on the one side and drive member base on the other.

This involves placing the interfaces inside the base of the drive member, which makes the structure relatively more complex, but distinctly more reliable as it involves the quality of transmission of movement between actuators on the one side and drive member base on the other.

The base of the drive member is secured to the drive member and fixed relative to the drive member.

For this purpose, according to the invention, a movement transmission chain is provided comprising:A drive member base for a mobile element;Three actuators piloting the base of the drive member respectively along three mutually distinct translation directions, by means of three respective interfaces with the base of the drive member;

Characterized in that the intersection of the average surfaces of the three interfaces is located in the central region of the base of the drive member.

For this purpose, according to the invention, a movement transmission chain is also provided comprising:A base of the drive member for a mobile element;Three actuators piloting the base of the drive member respectively along three mutually distinct translation directions, by means of three respective interfaces with the base of the drive member;

Characterized in that the three interfaces are substantially flat;

In that the three interfaces are mutually orthogonal;

And in that these three interfaces are nested in each other.

In preferred embodiments of the invention, use could further be made of one and/or the other of the following arrangements:

Preferably the three translation directions are mutually orthogonal.

Preferably, the three interfaces are substantially flat, these three interfaces are mutually orthogonal, and these three interfaces are nested inside each other. In that way, the three interfaces can be concentrated relatively simply and truly effectively in the central region of the base of the drive member.

Preferably, the three interfaces are pressure plates transmitting the respective thrusts from the three actuators. With these flat plates, an effective transmission of thrust from the actuators is possible for relatively reduced overall volume.

Preferably, the first plate comprises two mutually orthogonal openings which are respectively traversed by a second plate and a third plate, the second plate comprises an opening which is traversed by the third plate, where the opening of the second plate is orthogonal to the two openings of the first plate, and the third plate is not traversed either by the first plate or the second plate. This way of nesting the plates inside each other is structurally relatively simple and still effective.

Preferably, each of these openings allows a travel of the plate passing through it, with this travel corresponding to the range of the actuator of the plate which passes through said opening, where this travel is greater than the thickness of the plate which passes through said opening. In fact, if one of the actuators moves, the base of the drive member must only move in the direction corresponding to this actuator which moved and not in the two directions corresponding to the actuators remaining motionless. To do that, the presence of these travels serves to disconnect the transmission of force coming from each of the various actuators from each other.

Preferably, each plate is mobile in translation along a direction parallel to the straight-line formed by the intersection of the two other plates. In that way the transmission of pairwise orthogonal forces between the actuators is easily maintained.

Preferably, each plate is connected to its actuator by two struts symmetric about the thrust axis of said actuator, preferably by four struts symmetric about the thrust axis of said actuator. Thus, the transmission of force from the actuator is well distributed on the corresponding plate.

Preferably, the base of the drive member is fixedly secured with each of the interfaces in a way that the movement of one of the interfaces automatically leads to the same movement of the base of the drive member. Thus, the transmission of force between the interfaces on the one side and the drive member base on the other is more direct.

Preferably, the base of the drive member is a cube inside of which the three interfaces are located. Thus, the overall volume of the base of the drive member is relatively reduced, whereas the interfaces are just the same fully contained inside the base of the drive member. The overall compactness thereof is consequently improved.

Preferably, the base of the drive member is a cube resulting from the assembly of eight smaller cubes assembled around interfaces. These eight small cubes represent the minimum number of subparts of the cube making up the base of the drive member so as to be able to assemble this cube around the set of three interfaces nested in each other.

Preferably, each plate is lodged between four smaller cubes on one side and four smaller cubes on the other side. The drive member base is thus completely symmetric and balanced.

Preferably, the central region is the center of gravity of the base of the drive member. The transmission of forces between actuators and drive member base is thus perfectly balanced because of the perfectly centered nature of the interfaces relative to the base of the drive member.

Preferably, the movement transmission chain includes a mobile element driven by the drive member.

Preferably, the materials used are low or even very low friction materials in order to allow interfaces nested in each other to slide easily.

In a preferred but nonexclusive application, the mobile element is a catheter or catheter guide, the drive member is a tightening member for a catheter or a catheter guide.

In the various figures, the same references designate identical or similar items.

FIG. 1schematically shows an arteriographic installation1. The arteriographic installation1is divided into two distinct areas: one operating room2and one command room3. The command room3can be close to the operating room2, separated from it by a simple x-ray blocking wall4, or remote. The equipment in the operating room2and the command room3are functionally connected to each other by wire, wireless or network, etc.

The operating room2includes an operating table5receiving a patient6. The operating room2can also include a medical imager7in particular for imaging by x-ray, comprising a source8and a detector9arranged on either side of the patient, which could be mobile relative to the patient.

The arteriographic installation1comprises a robot10arranged in the operating room2.

The arteriographic installation1comprises a command station11arranged in the command room3. The command station11is suited for remotely commanding the robot10. The arteriographic installation1can also include, arranged in the control room3, one or more remote controls12for the imager7communicating with the imager7for controlling it from a distance. The arteriographic installation1can also include, arranged in the command room3, a screen13, communicating with the imager7, for viewing in real time in the command room3the images acquired by the imager7.

The robot10can include a container suited for holding a long flexible medical member15to be inserted in a patient's body. The long flexible medical member15could for example involve a member to be inserted in a canal of a patient and to be moved in this canal, in particular an artery or vein of the patient, through a catheter introducer providing an access opening into the patient. The long flexible medical member can in particular be a catheter. As a variant, the long flexible medical member can be a catheter guide. A guide generally has a transverse diameter less than that of the catheter, which is generally hollow over a portion close to the patient, even over its entire length, such that the guide can be displaced inside of it, in particular inside the body of the patient. The guide can also comprise a bent-back end.

The robot10may include a drive module for the long flexible medical member15. The drive module can be commanded from the command station11for driving the long flexible medical member relative to the patient along at least one degree of freedom, as will be described in detail subsequently. The drive module may include a communication box17providing an interface with the command station11. As needed, the robot10may include a local command box18, intended to command the robot from the operating room2if necessary.

It will additionally be noted that all commands and feedback available in the command room3can also be available in the operating room2in order for local operation, such as for example a command19for the imager and the screen20with which to see the images acquired by the imager7.

The hollow long flexible medical member15can be connected to a connector56with which to inject a contrast product making the imaging inside the long flexible medical member easier. The arteriographic installation can include a contrast product injector57connected to the connector56and commanded by a command58arranged in the command room3. A command59for the contrast product injector can also be present locally in the operating room2.

FIG. 2shows a drive module31according to a first embodiment. This drive module31is suited for driving a long flexible medical member15extending along the longitudinal direction X. It will be noted that the longitudinal direction X near the drive module31is not strictly the same as that of the long flexible medical member15near its end but that a translation and/or a rotation of the long flexible medical member15along/around the longitudinal direction X near the drive module31will drive a translation and/or a rotation of the long flexible medical member15respectively along/around the longitudinal direction thereof near the end thereof.

The drive module31includes a base132and at least one drive member24mounted mobile relative to the base132. The drive member24is, for example, mounted mobile relative to the base132.

In the example shown, the drive module31further comprises a second drive member24′. The drive member24, also called hereafter first drive member, and the second drive member24′ together form a pair of drive members33. The pair of drive members33comprises two drive members which together engage for generating a movement of the long flexible medical member15relative to the base132. In the example shown, the second drive member24′ is mounted mobile relative to the base132. The second drive member24′ is, for example, mounted mobile relative to the base132.

The first drive member24and the second drive member24′ are paired for simultaneous movement. For example, the first and second drive members24,24′ can be commanded individually, independently of each other, but according to synchronized respective commands. As a variant, a shared command can be provided which is distributed to one and the other of the first and second drive members24,24′ by mechanical or electronic connection between their command systems.

Each drive member24,24′ comprises a drive surface34,34′ respectively. The long flexible medical member15is arranged between the drive surfaces34,34′ of the drive members24,24′ of a single pair. To set the ideas, the drive surfaces34,34′ are separated from each other along the direction Y.

The pair of drive members24,24′ can be placed in a released configuration, shown inFIG. 2, in which the drive surface34,34′ of the drive members24,24′ of the pair of drive members33is not engaged with the long flexible medical member15.

The pair of drive members33can be placed in a drive configuration in which the drive surfaces34,34′ of the drive members of the pair of drive members are engaged with the long flexible medical member15to be driven. The force applied by a drive member on the long flexible medical member in this configuration is for example of order a few Newtons (5-30 N for example). The restoring means, described above, are arranged for example to return the pair of drive members to released configuration, which provides a safety function, for example in case of outage of electric power.

To place the pair of drive members33alternately in released and drive configurations, a relative displacement of one towards the other of the two drive members24,24′ can be ordered. This displacement can for example be the displacement of one drive member24relative to the base with the other remaining fixed. As a variant, the two drive members24,24′ can both move towards each other relative to the base.

In the example, a displacement along the Y direction is intended.

In the embodiment shown, both drive members24,24′ are mobile relative to the base along one degree of freedom. This degree of freedom is different from the one allowing the alternate placement of the drive members in the released and drive positions. It is in particular provided that the drive members24,24′ are mobile relative to the base along one degree of freedom in their drive configuration. Thus, the displacement of the drive members along one degree of freedom in their drive configuration generates a displacement of the long flexible medical organ relative to the base132.

An example of reduction of such a system to practice is shown below in connection withFIG. 3.

This sample embodiment is provided solely for illustration of a concrete sample embodiment of an actuation system.

FIG. 3includes a fixed base132shared by four actuation systems. Each actuation system commands the movement of one respective drive member, not shown, secured to a respective cube60,60′,60″,60″. The cubes60,60′,60″,60″ correspond respectively to drive members not shown in the figure. These cubes60,60′,60″,60″ are the corresponding drive member bases.

The reference15is used for designating alternatively the guide15″, the catheter15′, or generally a long flexible medical member to be inserted into the body of the patient. It can for example involve a catheter for a procedure. Such a catheter for a procedure can have a diameter less than the catheter, so as to be guided inside thereof, coaxially inside the patient, and be hollow so as to be guided on the guide inside the patient.

The guide15″ has a front end15″ a slightly curved relative to the main longitudinal axis of the guide and extending out from the front end of the catheter15′. The catheter15′ can undergo two distinct motions:A translation along the longitudinal axis thereof;A rotation around the longitudinal axis thereof.

These movements can be generated in one direction or the other.

As needed, the catheter15′ can undergo a combined movement of the two simple movements described above.

As needed, the catheter15′ can undergo two combined movements of the two simple movements described above, according to combinations.

What was described above concerning the catheter also applies to the guide.

In some cases, the catheter itself is provided with a curved end, either in order to allow navigation on the same principle as a guide, or to facilitate positioning in an anatomical area having a specific curvature.

Subsequently, only the operation of one cube will be described. Reference, as an example, is made to cube60″. The cube60″ is associated with three actuators26x,26y,26z(this last one is not visible, similar in all ways to the actuators26xand26y, and located under the base132). The actuator26yis used to move the cube60″ along the Y direction, while also allowing a movement of the cube60″ both along the X and Z directions relative to the actuator26yfor some range of movement.

FIG. 4is a perspective view of a sample embodiment of the intersection and nesting of interfaces between actuators on the one side and drive member base on the other.

Three actuators610,620,630exert a force along three mutually orthogonal directions Y, X, Z.

The actuator610exerts the force thereof in the Y direction via four struts611pushing the four corners of a first pressure plate612which constitutes the interface between the actuator610and the base of the drive member. The first plate612includes a first opening613through which passes a second plate622constituting the interface between the actuator620and the drive member base. This first opening613comprises a travel in the X direction so as to allow the range of the actuator620and the associated second plate622along the X direction without moving the first plate612. The first plate612includes a second opening614through which passes a third plate632constituting the interface between the actuator630and the drive member base. This second opening614comprises a travel in the Z direction so as to allow the range of the actuator630and the associated third plate632along the Z direction without moving the first plate612.

The actuator620exerts the force thereof in the X direction via four struts621pushing the four corners of the second pressure plate622which constitutes the interface between the actuator620and the base of the drive member. The second plate622includes a third opening623through which passes a third plate632constituting the interface between the actuator630and the drive member base. This third opening623comprises a travel in the Z direction so as to allow the range of the actuator630and the associated third plate632along the Z direction without moving the second plate622.

The actuator630exerts the force thereof in the Z direction via four struts631pushing the four corners of the second pressure plate632which constitutes the interface between the actuator630and the base of the drive member. The third plate632does not have any opening.

FIG. 5is a perspective view of a sample embodiment of the drive member base.

The base of the drive member includes a cube640which could be any one of the cubes60,60′,60″ or60″ fromFIG. 3. This cube640comprises eight small cubes641assembled together at the eight vertices of the cube640. In reality, the small cubes641are only portions of small cubes on three faces. Circular opening643are arranged on some faces of the small cubes641and oblong openings642are arranged on other faces of small cubes641. The circular openings643, like the oblong opening642, are intended to receive the struts611,621and631from various plates612,622and632.

FIG. 6is a perspective view of a sample embodiment of assembly between the interfaces on the one side and the drive member base on the other.

The struts611,621and631from various plates612,622and632can pass more or less deeply in the various openings642and643, in that way allowing plates612,622and632respectively to move the cube640in the directions Y, X and Z respectively. The plates612,622and632push or pull the small cubes641forming together the cube640.

FIG. 7is another perspective view of a sample embodiment of assembly between the interfaces on the one side and the drive member base on the other.

On this side, the small cubes641do not comprise any opening, but only a key cap650. This tip650is going to be able to securely carry and fix the drive member24shown inFIG. 2.