WO2024141948A1

WO2024141948A1 - Control method for the movement of a robotic surgical instrument exiting or entering the field of view of a viewing system, and related robotic system for surgery

Info

Publication number: WO2024141948A1
Application number: PCT/IB2023/063284
Authority: WO
Inventors: Emanuele Ruffaldi; Massimiliano Simi; Antonio DI GUARDO
Original assignee: Medical Microinstruments Inc.
Priority date: 2022-12-29
Filing date: 2023-12-27
Publication date: 2024-07-04

Abstract

A method for controlling a slave device of a robotic system for medical or surgical teleoperation is described. The robotic system, to which the method is applied, comprises at least one master device 110 adapted to be moved by an operator 150, at least one slave device comprising a surgical instrument 170 adapted to be controlled by the master device, and further comprises viewing means configured to display to the operator 150 images and/or videos of a viewing space associated with a teleoperation area in which the surgical instrument 170 operates. The method first comprises the entire step of defining a safety volume VS, included in the slave workspace but outside the viewing space, in accordance with the criterion that a safety level of the movement of the surgical instrument 170 is ensured in the safety volume VS limiting or eliminating risks of contact of the surgical instrument 170 with anatomical parts of a patient or elements supporting the surgical activity. The method then includes determining a position of the surgical instrument 170, to establish whether the surgical instrument 170 is inside the viewing space, or outside the viewing space but inside the safety volume VS, or outside the safety volume VS. The method then comprises the step of controlling the movement of the slave device in a manner dependent on the determined position of the surgical instrument 170, so that a movement of the surgical instrument 170 is allowed, in a limited operating mode, even when the surgical instrument 170 is outside the viewing space but inside the safety volume VS. A robotic system for medical or surgical teleoperation adapted to be controlled by the aforesaid control method is further described.

Description

Control method for the movement of a robotic surgical instrument exiting or entering the field of view of a viewing system, and related robotic system for surgery

DESCRIPTION

TECHNOLOGICAL BACKGROUND OF THE INVENTION

Field of application.

The present invention relates to a method and system for controlling a robotic system for medical or surgical teleoperation.

In particular, the invention relates to a control method for the movement of a robotic surgical instrument exiting or entering the field of view of a viewing system, and the related robotic system.

DESCRIPTION OF THE PRIOR ART.

In a system for robotic surgery, the field of view (FOV) provided by any associated viewing system associated therewith (endoscope, laparoscope, microscope or exoscope) is typically included in the workspace of the slave device (also defined a "slave workspace").

In other words, often, due to a high use of magnification, or a position of the camera which is very close to the work area, or a small workspace, or simply due to a large workspace of the slave device, the field of view FOV is a subspace, i.e., it represents a subset, of the workspace of the joints of the slave device.

Therefore, a movement of an instrument controlled by the master device can be mapped inside the slave workspace (i.e., inside the space of the slave joints) but outside the actual field of view FOV and therefore is not carried out under the complete control of the operator who, in a robotic teleoperation system, closes the control loop of each movement through his own view mediated by the viewing system.

For example, surgical gestures such as pulling a suture filament during the passage of the needle in tissues or making a knot, as well as the retraction of an organ or tissue, or a motion for gripping an object at the limits of the field of view FOV, can conduct movements of the robotic end terminals (or "end-effectors") outside the field of view FOV.

It is possible, and in some cases frequent, that the user, instead of continuously changing the operating field of view by reducing the zoom or moving his point of view on the scene so as to always frame all the surgical instruments, for convenience and speed, takes and moves an instrument outside of the field of view.

However, if not carried out with caution and experience, moving an instrument outside of the field of view can be dangerous and cause damage to the patient such as perforations and/or lacerations of the tissues. This is because robotic tools are usually much stiffer, stronger, or sharper than the tissue can withstand.

From such a situation, a further risk can arise deriving from the subsequent attempt of the operator to re-enter the FOV with the instruments while teleoperating and moving the instrument "blindly" (when it is no longer in the field of view) and thus significantly increasing the risk of damage to the patient; or to attempt an entry into teleoperation with an alignment phase with movement of the articulated instruments outside of the field of view.

A method is known from US 2022 000579, which includes, in a robotic system, the autonomous backwards movement of the endoscope when the instrument exits the field of view, so as to bring the instrument back into the FOV, widening the field. In particular, the instrument is maintained in the field of view by autonomously rotating (roll) the laparoscopic camera which has an FOV inclined by an angle (e.g., 30° or 45°) from the top of the endoscope, so as to achieve, rotating for example by a full turn, a panoramic view of the surgical site.

This solution is prone to some drawbacks such as, for example, discomfort due to the frequent movements of the viewing system (position and/or orientation) to follow the surgical instrument, as well as the delay in updating the panoramic image, and/or the corresponding frequent changes visible on the screen as a result of the repositioning of the camera which could disorient an operator during surgery.

It is known from US 2018 0025666 to control the camera, to move it, using for example the master controller during a suspended teleoperation state.

The known solutions, in the technical field considered, do not allow satisfactorily solving the aforesaid problems and drawbacks.

Therefore, in the technical field considered, there is a strong need to allow and control the enslaved movement of the slave device outside the FOV, depending on the master device, with expedients and based on control algorithms such as to solve or at least mitigate the aforesaid problems and drawbacks.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a method for controlling a slave device of a robotic system for medical or surgical teleoperation, in particular the movement of the robotic surgical instrument exiting or entering the field of view of a viewing system, which allows at least partially obviating the drawbacks complained above with reference to the prior art, and responding to the aforementioned needs particularly felt in the technical field considered. Such an object is achieved by a method according to claim 1 .

Further embodiments of such a method are defined in claims 2-36.

It is also an object of the present invention to provide a robotic system for medical or surgical teleoperation, configured to be controlled by the aforesaid method or for carrying out the aforesaid method. Such an object is achieved by a system according to claim 37.

Further embodiments of such a system are defined in claims 38-72.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the method according to the invention will become apparent from the following description of preferred embodiments, given by way of non-limiting indication, with reference to the accompanying drawings, in which:

- figures 1 and 2 show two respective embodiments of a robotic system for medical or surgical teleoperation according to the invention;

- figures 3, 3bis and 3ter depict respective simplified block diagrams of a robotic system of the invention, according to respective embodiments;

- figure 4 shows a behavior of the slave device, according to the prior art, in which the slave device, when a movement is commanded thereto which is outside a field of view FOV but inside a slave workspace, moves until it reaches the position inside the FOV closest to that commanded;

- figure 5 shows a slave workspace (in grey), the field of view FOV (in white), an operating sub-volume defined by thresholds along a main axis Z (vertical in the figure) and along a lateral axis X (horizontal in the figure), and also a Cartesian manipulator xyz;

- figure 5 bis depicts a screen of the robotic system in which the operating subvolume in figure 5 is displayed;

- figures 6-13 depict safety volumes defined by different embodiments of the method according to the invention;

- figure 14 shows a method for controlling the surgical instrument, provided in an embodiment of the method according to the invention, in which the surgical instrument exits the field of view up to a maximum distancing point, and then returns with a returning movement constrained in the delimited region indicated;

- figures 15 and 15 bis show indications on the screen of the robotic system indicating the exit point of the surgical instrument from the viewing space, according to two implementation options of the method;

- figure 16 shows a status diagram of the robotic system, according to an embodiment of the method of the present invention,

- figure 17 shows, by means of a flow chart, a further embodiment of the method.

DETAILED DESCRIPTION

With reference to figures 1 -17, a method for controlling a slave device of a robotic system for medical or surgical teleoperation is described.

The robotic system, to which the method is applied, comprises at least one master device 110 adapted to be moved by an operator 150, at least one slave device comprising a surgical instrument 170 adapted to be controlled by the master device, and further comprises viewing means configured to display to the operator 150 images and/or videos of a viewing space associated with a teleoperation area in which the surgical instrument 170 operates.

The master device 1 10 is preferably an "ungrounded"-type master device, without force feedback, for mono-lateral teleoperation. For example, thus, the master device can be a master mechanically constrained to an operating console and at the same time be of the “ungrounded”-type without force feedback, for mono-lateral teleoperation.

The master device 110 is preferably a master device of a type which is mechanically unconstrained to the operating console.

The method first comprises the step of defining a safety volume VS, included in the slave workspace but outside the viewing space, in accordance with the criterion that a safety level of the movement of the surgical instrument 170 is ensured in the safety volume VS limiting or eliminating risks of contact of the surgical instrument 170 with anatomical parts of a patient or elements supporting the surgical activity.

The method then includes determining a position of the surgical instrument 170, to establish whether the surgical instrument 170 is inside the viewing space, or outside the viewing space but inside the safety volume VS, or outside the safety volume VS.

The method then comprises the step of controlling the movement of the slave device in a manner dependent on the determined position of the surgical instrument 170, so that a movement of the surgical instrument 170 is allowed, in a limited operating mode, even when the surgical instrument 170 is outside the viewing space but inside the safety volume VS.

According to an embodiment of the method, the aforesaid safety volume VS is defined based on geometrical or construction criteria of the slave device or surgical instrument, and/or based on the geometry and architecture of the robotic system, and/or based on a surgical procedure setting. According to an embodiment of the method, the aforesaid safety volume VS is defined with respect to a surgical work surface, such a surgical work surface defines a surface on which the robotic surgical activity is carried out, during teleoperation, or a boundary of a working area of the surgical instrument close to anatomical parts of the patient.

In accordance with an embodiment of the method, the aforesaid safety volume VS is dynamically defined, during a teleoperation, depending on the most recent exit point, determined or recorded, of the surgical instrument 170 from the viewing space FOV.

In accordance with an embodiment of the method (shown for example in figure 6), the aforesaid safety volume VS comprises external surroundings of the viewing space which extend beyond the boundaries of the viewing space by a spatial tolerance e.

According to several possible implementation options of such an embodiment, the aforesaid spatial tolerance e is a predefined constant value, or a dynamically variable value, defined as a function of the speed of the surgical instrument 170 upon exiting the viewing space, or as a function of a scale factor between the movement of the master device and the consequent movement of the slave device.

In accordance with another embodiment of the method, the aforesaid safety volume VS comprises a cone or a cone trunk, defined around an exit direction of the surgical instrument from the viewing space.

According to several possible implementation options of such an embodiment (shown for example in figures 7 and 8), the aforesaid cone or cone trunk has a height h and an angular opening a around the exit direction of the surgical instrument from the viewing space.

Such a height and such an angular opening depend on the exit speed of the surgical instrument 170 from the viewing space, or depend on a scale factor between the movement of the master device and the consequent movement of the slave device, or depend on other kinematic parameters of the robotic system.

According to an implementation example of the method, the angular opening is inversely proportional to the exit speed or directly proportional to the scale factor, and the height is directly/inversely proportional to the exit speed or directly/inversely proportional to the scale factor.

According to another implementation example of the method, the angular opening of the cone with respect to coordinates associated with the viewing space is calculated/estimated as a function of the direction with which the surgical instrument reached the limit of the viewing space.

According to an implementation option, the vertex angle a of the cone is in a range between 30° and 60° depending on safety and usability criteria.

According to an implementation option, the height h of the cone, i.e., the maximum distance allowed in the safety volume from the viewing space, is in a range between 50mm and 100mm depending on the scale factor and the viewing system.

In accordance with another embodiment of the method (shown for example in figure 9), the aforesaid safety volume VS comprises a cylinder or a tubular volume, defined along the longitudinal axis of the surgical instrument, so as to allow the surgical instrument to move only along the dominant axis of the surgical instrument or therearound, when the surgical instrument is outside the viewing space FOV.

In accordance with another embodiment of the method (shown for example in figure 10), the aforesaid safety volume VS comprises a convex polytope dependent on the exit point of the surgical instrument 170 from the viewing space, defined so as to exclude parts of space which are at a shorter distance from the surgical work surface than the distance from the surgical work surface of said exit point, so as to prevent crossing the surgical work surface and/or the original work surface and/or the work surface on which the surgical instrument was previously operating.

According to an implementation option of such an embodiment, the movement of the surgical instrument upon exiting the viewing space and outside it is not allowed while approaching the surgical work surface in a direction Z perpendicular to the surgical work surface X-Y, to avoid sinking and penetration in the patient’s tissue.

According to an embodiment of the method (shown for example in figure 11 ), the aforesaid safety volume VS comprises a volume or half-space comprising all the points that are farther from the surgical work surface with respect to a focal point of the viewing system.

According to an embodiment of the method (shown for example in figure 12), the aforesaid safety volume VS comprises a cavity-shaped volume, having an angular opening calculated or estimated from a leading angle 0 of an axis of the surgical instrument 170 and comprising points that are farther from the surgical work surface with respect to a focal point of the viewing system.

According to an embodiment of the method, the aforesaid safety volume VS consists of any combination of one or more volumes mentioned in the embodiments shown above. Further implementation examples of safety volume, provided by the method, are shown below.

Consider the Euclidean distance between the current reference position in coordinates of the slave device and the last point observed inside the vision space, expressed by the same coordinates.

If such a distance is greater than a prefixed threshold (for example 2mm, i.e., calculated as 20% of the viewing space in metric units) then the teleoperation is interrupted in this case.

According to other implementation options, instead of a distance between points defined by three-dimensional coordinates, the distance between the slave device and the surface of the viewing space remapped in the space of the slave device is considered, i.e., between the slave device and the center of the viewing space in coordinates of the slave device. Such an option allows expressing the distance with respect to the volume itself, and not with respect to the distance traveled.

According to another implementation example, taking into account the relationship between the workspace of the slave device and the viewing space, the distance between a component with respect to the work surface of the viewing space at the exit point and a complementary distance is weighted. In this case, it is prevented from descending further.

According to another implementation example (shown for example in figure 13), account is taken of the knowledge of prohibited regions ("non-penetration areas") within the viewing space, expressed in the space of coordinates of the slave device described according to containment volumes, for example ellipsoids or parallelepipeds. The safety volume excludes the aforesaid prohibited regions in these cases. Approaching such prohibited regions first produces audible or visual or haptic warnings and then, if necessary, the exit from teleoperation.

According to an embodiment of the method, the aforesaid viewing space is defined by a field of view (FOV) of the viewing means.

Such an implementation option refers to a robotic system having viewing means, or a generic viewing system (comprising digital image/video acquisition means), capable of capturing a portion of the world observed through appropriate lens or light guide systems.

With a terminology known in the technical field considered, such a portion of the world of which an image or video is acquired has an extension referred to as the "Field of View" or (FOV) which is typically represented in angular units taken along the diagonal or one of the axes of the digital image/video acquisition system.

According to another implementation option of the method, said viewing space is defined by a predefined subset of the field of view (FOV) of the viewing means.

According to another implementation option of the method, the aforesaid viewing space is defined by a field-of-view workspace, consisting of a geometric volume, in a reference coordinate system of the robotic system, associated with the aforesaid field of view.

Such a field-of-view workspace (hereinafter also referred to as "FOV Workspace") can for example correspond to a volume, for example a trapezoid which goes from the lens to infinity and centered in the main axis of the optical system, which is capable of representing the field of view of a digital viewing system, for example for lenses with "Fields of View" FOV less than 180 degrees. Once a plane is fixed with respect to the lens, it is possible to evaluate the extension of the field of view in metric terms by evaluating the portion of the plane which intersects the "FOV Workspace", and generally such a plane is orthogonal to the main axis. The diagonal of the rectangle of said plane at a certain distance can be defined as "FOV Diagonal".

According to another implementation option of the method, the aforesaid viewing space is defined by geometric limits of the field of view, consisting of a boundary surface of the aforesaid viewing workspace, in the reference coordinate system of the robotic system.

For example, the field-of-view workspace is constructed with respect to the trapezoid originating in the camera image plane of the viewing system. It is possible to construct simplified geometries therefrom, referred to as "field-of-view workspace limits" (FOV Workspace Limits) which are imposed to limit the movement of the slave device. Such geometries can be defined as planes orthogonal to the viewing system or as curved surfaces which in any case are defined inside the field-of-view workspace.

According to several possible embodiments, the aforesaid viewing means comprise at least one camera 120 or comprise an endoscope and/or a laparoscope and/or a microscope and/or an exoscope.

According to an implementation option, the viewing means comprise a stereoscopic viewing system comprising two cameras, each of which defines a respective "FOV Workspace" (175L, 175R), referred to as the "field-of-view workspace of camera L" (FOV Workspace L) and "field-of-view workspace of camera R" (FOV Workspace R). The intersection of the aforesaid two field-of-view workspaces of camera L and R produces a “common field-of-view workspace” which ensures the maximum visibility of the objects in the scene.

For a given point in such a "common field-of-view workspace", the disparity or difference (in a given unit) of the lateral position of the same element can be calculated. Excessive disparity can lead to lack of depth perception and thus a blurring effect.

For example, such viewing means comprise digital viewing means suitable for robotic surgery and/or microsurgery.

According to an embodiment of the method, the step of controlling the movement of the slave device in a manner dependent on the determined position of the surgical instrument 170 comprises allowing the movement of the surgical instrument 170, in a normal operating mode, when the surgical instrument 170 is inside the aforesaid field of view (FOV).

In accordance with an embodiment of the method, the aforesaid step of defining a safety volume VS comprises calculating the aforesaid safety volume VS by means of one or more Computer Vision algorithms operating in real time based on digital data derived from the viewing means.

According to another embodiment of the method, the aforesaid step of defining a safety volume VS comprises calculating the aforesaid safety volume VS by means of one or more Computer Vision algorithms operating on digital data derived from second viewing means having a second field of view FOV2, or based on digital data/images recorded in a pre-operation phase.

According to another embodiment of the method, the safety volume is defined as a volume surrounding the viewing space, from which sub-volumes or non-penetrating sub-areas, in which the movement of the surgical instrument is not allowed, are excluded.

According to different implementation options of such an embodiment, Computer Vision software algorithms identify anatomical areas or volumes not to be penetrated during teleoperation both on teleoperation magnified image FOV1 and on reduced zoom processed image FOV2, so that the movement of the instrument outside the field of vision, and/or in FOV2, and/or in both FOV1 and FOV2, is allowed only when carried out in the free space which does not penetrate identified tissues, and in the same manner the movement which generates the penetration of previously recorded and identified tissues or areas or volumes is inhibited if and only if the viewing parameters are not altered and/or modified between two detection instants t1 and t2.

The control unit of the robotic system stores the movement and coordinates of the instrument carried out in an FOV1 with z1 (or parameters of FOV1 ) at a time t1 . In a continuous session carried out at a later time t2, the system allows movements outside the FOV1 only if such movements repeat, within one epsilon, movements carried out in t1 in a FOV2 with parameters z2 and in which FOV2 > FOV1 .

In an implementation option and/or in any of the above options, once the instrument is allowed to exit from the FOV1 according to a trajectory p1 , returning into the FOV1 is allowed only by travelling along the same trajectory p1 , and/or around p1 and/or a cone around p1 and/or where p1 is contained.

Such a choice is due to the fact that p1 is allowed since it is considered safe by the several "computer vision" algorithms, or that p1 is carried out inside an FOV2 and the viewing system is kept unchanged except for the zoom FOV2, whereby the system still considers a movement carried out and repeated by the user outside FOV1 safe, only if the trajectory is equivalent to that done previously when FOV2 was displayed.

Such trajectories p1 are allowed outside FOV1 only if they have a mainly straight trajectory and not a curvilinear trajectory or with multiple and repeated concavities.

Such features can be provided in an implementation option whereby the viewing system is static between the instants t1 and t2 and only the zoom is changed, determining FOV1 and FOV2.

In accordance with an embodiment of the method, the aforesaid step of defining a safety volume VS comprises calculating such a safety volume VS by means of one or more Computer Vision algorithms operating on digital data derived from second viewing means having a second field of view FOV2, or based on digital data/images recorded in a pre-operation phase.

According to an implementation option, the safety volume is defined as a volume surrounding the viewing space, from which sub-volumes or non-penetrating subareas, in which the movement of the surgical instrument is not allowed, are excluded.

In accordance with another embodiment of the method, the aforesaid step of defining a safety volume VS comprises calculating such a safety volume VS as a volumetric extension of the viewing space.

In accordance with another embodiment of the method, the aforesaid step of defining a safety volume VS comprises calculating said safety volume VS based on kinematic or mechanical information of the robotic system and/or slave device.

In accordance with another embodiment of the method, the aforesaid step of defining a safety volume (VS) comprises:

- recording the exit point and the exit orientation of the surgical instrument from the viewing space, based on digital data or on the provided image of the viewing means, and expressing the aforesaid exit point and exit orientation in terms of coordinates referring to a coordinate system of the slave workspace;

- calculating or defining the aforesaid safety volume VS based on said exit point and exit orientation of the surgical instrument from the viewing space.

In accordance with an embodiment of the method, the aforesaid step of determining a position of the surgical instrument 170 comprises determining a current position of the surgical instrument 170 and/or the presence of the surgical instrument 170 in the viewing space based on digital data deriving from the viewing means.

According to another embodiment of the method, the aforesaid step of determining a position of the surgical instrument 170 comprises:

- mapping the aforesaid viewing space in a corresponding slave field-of-view workspace, in a slave reference coordinate system associated with the slave device;

- determining the position of the surgical instrument 170 in terms of respective position coordinates in the aforesaid slave reference coordinate system;

- determining the position of the surgical instrument 170 with respect to the allowed space correlated to the viewing space based on a comparison between the aforesaid position coordinates and the aforesaid slave field-of-view workspace, in the slave reference coordinate system.

According to an implementation option of the aforesaid embodiment, the method further comprises the following steps:

- defining, in the slave reference coordinate system, a slave kinematic workspace 175, based on physical movement limits of the slave device and/or operating constraints not correlated to the viewing means;

- defining, in the slave reference coordinate system, an actual slave workspace 200, corresponding to the intersection of the aforesaid slave field-of-view workspace and slave kinematic workspace 175.

In such a case, the step of controlling the slave device movement comprises controlling the slave device movement so that the movement of the surgical instrument 170 is allowed only if the surgical instrument 170 is inside the aforesaid actual slave workspace 200.

More specifically, for example, a field-of-view slave workspace (or "FOV Slave Workspace") can be defined as a workspace geometrically equivalent to the field-of-view slave workspace but transposed by means of a mapping function (e.g., rototranslation) in the reference system of the slave device. Such an "FOV Slave Workspace" is intersected with the slave kinematic workspace 175 so as to ensure that it is always therein, and therefore results in the aforesaid actual slave workspace 200, which can then be used by the various movement limitation algorithms.

According to an implementation option, the FOV slave workspace FOV is contained inside the slave kinematic workspace 175.

According to another implementation option, the field-of-view slave workspace is only partially contained inside the slave kinematic workspace 175.

According to an implementation option, the actual slave workspace 200 is the intersection of the slave kinematic workspace 175 and the field-of-view slave workspace.

According to an implementation option, the actual slave workspace 200 is reduced and limited by the field-of-view slave workspace.

According to several possible implementation options of the method, such a limitation can be done by means of a pure geometric intersection between the two convex geometries, or simplified in a parallelepiped or in a pyramid trunk inside such an intersection (thus calculated by the software, for example, to have an actual workspace 200 with a desired shape/usability).

According to an embodiment of the method, the aforesaid step of determining a position of the surgical instrument 170 with respect to the viewing space is carried out cyclically and/or continuously in real time, to verify the position or presence of the surgical instrument 170 in the viewing space or in the actual slave workspace 200 in real time.

According to an embodiment of the method, the aforesaid step of determining a position of the surgical instrument 170 with respect to the allowed space correlated to the viewing space comprises calculating and/or determining the position of a real point belonging to the surgical instrument or the position of a virtual point integral with the surgical instrument 170, based on images provided by said viewing system.

According to an implementation option, the aforesaid step of determining a position of the surgical instrument 170 comprises determining the position of a virtual control point 600 of the slave device (for example placed between the tips 171 , 172 or "jaws" 171 , 172 of the surgical instrument 170).

According to another implementation option, the aforesaid step of determining a position of the surgical instrument 170 comprises determining the position of at least one of the tips 171 , 172 of the surgical instrument 170.

According to an implementation option, the aforesaid step of determining a position of the surgical instrument 170 comprises determining the position of at least one of the links of a hinged wrist (or "end-effector") 177 included in the surgical instrument 170.

According to another implementation option, the aforesaid step of determining a position of the surgical instrument 170 comprises determining the position of a distal portion of a positioning shaft 179 or shaft 179 near the hinged wrist 177 of the surgical instrument 170.

In accordance with an embodiment of the method, the viewing space comprises the aforesaid field of view (FOV) of the viewing means, or a predefined subset of the field of view (FOV).

According to another embodiment, the method comprises the further step of defining limits or edges of the viewing space which in turn define upper and lower thresholds for the movements allowed to the slave device.

According to an implementation option, the aforesaid limits or edges comprise a threshold perimeter on a plane XY which is orthogonal to a depth direction Z of the field of view FOV.

Such a threshold perimeter defines upper/lower thresholds for movements in the aforesaid plane XY and/or along orthogonal axes X, Y belonging to the plane XY. The threshold perimeter is calculated depending on the distance of the plane XY with respect to the viewing means.

According to another implementation option, the aforesaid limits or edges comprise, in addition to the threshold perimeter on a plane XY, also lower/upper thresholds along the axis of the depth direction Z of the field of view FOV.

In such a case, the aforesaid lower/upper thresholds along the axis of the depth direction Z are determined based on a good focusing of the viewing means, evaluated and calculated in real time using the data provided by the viewing means, or based on the field depth of the viewing means in a given configuration within a predefined focus acceptability range provided by the viewing means.

In an embodiment the field-of-view workspace limits are defined as a pyramid trunk defined by a Z as a combined function of X, Y and Z are calculated taking into account the intersecting workspace of a stereoscopic viewing system.

According to an implementation option, upper/lower thresholds are defined to avoid entering areas with excess disparity between the two points of view which lead to a blurred view for the operator.

According to an embodiment of the method, the aforesaid step of controlling the movement of the slave device comprises:

- allowing the surgical instrument 170 to exit the viewing space and/or a field- of-view FOV space and/or viewing space limits;

- allowing the movement of the surgical instrument 170, in a limited operating mode, if it is outside the viewing space but inside the safety volume VS, maintaining a teleoperation state;

- not allowing the movement of the surgical instrument 170 if it is outside both the viewing space and the safety volume VS;

- allowing the surgical instrument 170 to return from the safety volume VS to the viewing space and/or field-of-view FOV space and/or within the viewing space limits, maintaining a teleoperation state.

As noted above, in an implementation option, the method provides entering a special mode (or "limited" mode) when a command of the master device brings the position of the surgical instrument outside the field of view FOV, and until the surgical instrument returns inside the field of view FOV.

In such a case, the method includes allowing the movement outside the FOV, when the position outside the FOV is within a defined safety volume VS and/or allowed distancing/return volume, in the space of the slave device, characterized by new limits and within which the surgical instrument can move.

According to an embodiment of the method, the aforesaid step of allowing the movement of the surgical instrument 170 in a limited operating mode comprises controlling the slave device to move with a limited or reduced speed, less than the maximum speed that is achievable and/or allowed when the slave device is inside the viewing space.

According to another embodiment of the method, the aforesaid step of allowing the movement of the surgical instrument 170 in a limited operating mode comprises controlling the slave device to move with a scale factor, between master device and slave device, which is increased with respect to the scale factor provided inside the viewing space.

In accordance with an embodiment of the method, the aforesaid step of allowing the movement of the surgical instrument 170 in a limited operating mode comprises: if the surgical instrument reaches the edge or limit of the safety volume VS, allowing a movement of the surgical instrument only along the edge or limit of the safety volume VS, or temporarily blocking the surgical instrument at the point in which it reached said edge or limit. According to an embodiment of the method, the aforesaid step of allowing the movement of the surgical instrument 170 in a limited operating mode comprises constraining or inhibiting one or more degrees of freedom of the surgical instrument 170.

In accordance with an embodiment of the method, the aforesaid step of allowing the surgical instrument 170 to return from the safety volume VS to the viewing space comprises:

- discriminating an exiting and/or distancing phase of the surgical instrument 170 from the viewing space, where the distance of the surgical instrument from the edge of the viewing space increases and where said safety volume VS is an exit safety volume calculated in relation to the exiting and/or distancing phase, from a returning phase of the surgical instrument 170 towards and into the viewing space, where the distance of the surgical instrument from the edge of the viewing space decreases;

- at the beginning and during the returning phase, calculating a return safety volume other than, and contained in, the exit safety volume;

- controlling the movement of the surgical instrument 170 so that it remains within said return safety volume during the returning phase.

According to an implementation option, the aforesaid return safety volume comprises a containment volume including all the coordinates traveled by the surgical instrument 170 during the exiting and distancing phase, for example a containment cone trunk or another containment geometric figure (for example, “spline tubes”).

In such a case, controlling the movement of the surgical instrument 170 during the return step comprises constraining the surgical instrument 170 to stay inside the return safety volume through a translation limitation or a speed limitation, in which the return speed is less than the exit speed.

According to an embodiment, the method includes keeping the robotic system and the slave device in a teleoperation state, if and when the surgical instrument 170 is inside the viewing space or the safety volume VS.

According to another embodiment, the method includes stopping the teleoperation of the robotic system, or exiting a teleoperating condition of the robotic system, if and when the surgical instrument 170 exits the safety volume, being thus outside both the safety volume and the viewing space.

In accordance with another embodiment, the method comprises the further step of allowing and/or enabling alignment operations between the master device 110 and the slave device 170 and/or allowing an entry into teleoperation even when the surgical instrument 170 is outside the viewing space but only if it is inside the safety volume VS. In accordance with another embodiment, the method comprises the further step of allowing and/or enabling alignment operations between the master device 110 and the slave device 170 and/or allowing an entry into teleoperation following an exit from the teleoperation phase for having reached the edge or limit of the safety volume VS.

According to an embodiment, the method is applied to a robotic system comprising a plurality of slave devices and respective surgical instruments.

In such a case, the method steps are carried out for each of the slave devices and respective surgical instruments.

According to an embodiment, the method further includes providing the operator with visual and/or auditory and/or haptic alerts when the device is close to the limits or edges of the viewing space and/or when the device is close to the limits or edges of the safety volume VS.

According to an embodiment, the method further includes providing activation means, for example a pedal, which, when actuated by an operator of the robotic system, allow the movement of the surgical instrument outside the viewing space or the safety volume.

In accordance with an embodiment (shown for example in figures 15 and 15bis), the method further includes providing on-screen visual elements to guide an operator while performing the return of the surgical instrument 170 to the viewing space, or to inform the operator about the exit of the surgical instrument 170 from the viewing space.

According to an implementation option, appropriate overlays representing the safety volume are used. Such a representation is superimposed on the image of the viewing system.

According to another implementation option, an indicator is represented on the edge of the viewing space FOV the position of which indicates the most likely return point, and the color of which indicates the distance on a graduated scale and the shape of which could indicate if it is in the return phase.

According to another implementation option, when it comes close to the exit distance from teleoperation, the display alerts the user more consistently.

According to an implementation option, the viewing space FOV is depicted small and the safety volume region therearound is visually displayed (i.e., "virtual unzoom", which can be activated once a certain distance has been exceeded).

In such a case, the image of the viewing system is appropriately scaled at the center of the screen surrounded by a space of uniform color (e.g., gray) and the projection of the exiting instrument is indicated there. According to an implementation option, shown in the flow chart in figure 17, teleoperation is exited outside the viewing space FOV and the safety volume is calculated, and then a limited teleoperation phase is entered.

Referring again to figures 1 -17, a robotic system 100 for medical or surgical teleoperation, included in the present invention, is described below.

Such a robotic system comprises at least one master device 1 10, adapted to be moved by an operator 150; at least one slave device comprising a surgical instrument 170 adapted to be controlled by the master device; viewing means configured to display to the operator 150 images and/or videos of a viewing space associated with a teleoperation area in which the surgical instrument 170 operates; and a control unit configured to control the slave device, during a teleoperation, based on movements of the master device.

The control unit is further configured to carry out the following actions:

- defining a safety volume VS, included in the slave workspace but outside the viewing space, in accordance with the criterion that a safety level of the movement of the surgical instrument 170 is ensured in the safety volume VS limiting or eliminating risks of contact of the surgical instrument 170 with anatomical parts of a patient or elements supporting the surgical activity;

- determining a position of the surgical instrument 170, to establish whether the surgical instrument 170 is inside the viewing space, or outside the viewing space but inside the safety volume VS, or outside the safety volume VS;

- controlling the movement of the slave device in a manner dependent on the determined position of the surgical instrument 170, so that a movement of the surgical instrument 170 is allowed, in a limited operating mode, even when the surgical instrument 170 is outside the viewing space but inside the safety volume VS.

According to several possible implementation options of the robotic system, the control unit is configured to carry out a method for controlling a slave device according to any one of the embodiments shown in this description.

As can be seen, the objects of the present invention as previously indicated are fully achieved by the method and system disclosed above by virtue of the features described above in detail.

In particular, the present method, instead of continuously modifying the operating field of view by reducing the zoom or moving the point of view thereof on the scene, allows the robotic system to remain (or enter) in a special state (i.e., a "limited operating mode") of teleoperation when and if the surgical instrument(s) is/are taken out of the field of view FOV; In such a state, a movement of the surgical instrument is allowed even outside the FOV, as long as it is in a defined safety volume to comply with safety criteria while being outside the viewing space.

This allows advantages in terms of time and intuitiveness for the user during use, as well as maintaining adequate safety.

The method shown is based on technical solutions adapted to allow movement of instruments outside a viewing space which are safe for the patient and maintain utility and intuitiveness for the operator/surgeon.

Those skilled in the art may make changes and adaptations to the embodiments of the method and system described above or can replace elements with others which are functionally equivalent in order to meet contingent needs without departing from the scope of the following claims. Each of the features described as belonging to a possible embodiment can be implemented irrespective of the other embodiments described.

Claims

1. A method for controlling a slave device of a robotic system for medical or surgical teleoperation, wherein said robotic system comprises at least one master device (110) adapted to be moved by an operator (150), at least one slave device, comprising a surgical instrument (170) adapted to be controlled by the master device so as to move inside a slave workspace of the slave device, and viewing means (120) configured to display to the operator (150) images and/or videos of a viewing space associated with a teleoperation area in which the surgical instrument (170) operates, wherein the method comprises:

- defining a safety volume (VS), included in the slave workspace but outside the viewing space, in accordance with the criterion that a safety level of the movement of the surgical instrument (170) is ensured in the safety volume (VS) limiting or eliminating risks of contact of the surgical instrument (170) with anatomical parts of a patient or elements supporting the surgical activity;

- determining a position of the surgical instrument (170), to establish whether the surgical instrument (170) is inside the viewing space, or outside the viewing space but inside the safety volume (VS), or outside the safety volume (VS);

- controlling the movement of the slave device in a manner dependent on the determined position of the surgical instrument (170), so that a movement of the surgical instrument (170) is allowed, in a limited operating mode, even when the surgical instrument (170) is outside the viewing space but inside the safety volume (VS).

2. A method according to claim 1 , wherein said safety volume (VS) is defined:

- based on geometrical or construction criteria of the slave device or surgical instrument, and/or based on the geometry and architecture of the robotic system, and/or based on a surgical procedure setting, and/or

- with respect to a surgical work surface, wherein said surgical work surface defines a surface on which the robotic surgical activity is carried out, during teleoperation, or a boundary of a working area of the surgical instrument close to anatomical parts of the patient.

3. A method according to claim 2, wherein said safety volume (VS) comprises:

- external surroundings of the viewing space which extend beyond the boundaries of the viewing space by a spatial tolerance (e), and/or

- a cone or cone trunk, defined around an exit direction of the surgical instrument from the viewing space, and/or

- a cylinder or a tubular volume, defined along the longitudinal axis of the surgical instrument, and/or

- a convex polytope dependent on the exit point of the surgical instrument (170) from the viewing space, defined so as to exclude parts of space which are at a shorter distance from the surgical work surface than the distance from the surgical work surface of said exit point so as to prevent crossing the surgical work surface and/or the work surface on which the surgical instrument was previously operating, and/or

- a volume or half-space comprising all the points that are farther from the surgical work surface with respect to a focal point of the viewing system, and/or

- a cavity-shaped volume, having an angular opening calculated or estimated from a leading angle of an axis of the surgical instrument (170) and comprising points that are farther from the surgical work surface with respect to a focal point of the viewing system.

4. A method according to claim 2 or claim 3, wherein the safety volume (VS) is dynamically defined, during a teleoperation, depending on the most recent exit point, determined or recorded, of the surgical instrument (170) from the viewing space.

5. A method according to claim 3 and/or claim 4, wherein said safety volume (VS) comprises said external surroundings of the viewing space, and said spatial tolerance (e) is a predefined constant value, or a dynamically variable value, defined as a function of the speed of the surgical instrument (170) upon exiting the viewing space, or as a function of a scale factor between the movement of the master device and the consequent movement of the slave device.

6. A method according to claim 3 and/or claim 4, wherein said safety volume (VS) comprises said cone or cone trunk, having a height and an angular opening around the exit direction of the surgical instrument from the viewing space, wherein said height and said angular opening depend on the exit speed of the surgical instrument (170) from the viewing space, or depend on a scale factor between the movement of the master device and the consequent movement of the slave device, or depend on other kinematic parameters of the robotic system.

7. A method according to claim 6, wherein the angular opening is inversely proportional to the exit speed or directly proportional to the scale factor, and the height H is directly/inversely proportional to the exit speed or directly/inversely proportional to the scale factor, and/or wherein the angular opening of the cone with respect to coordinates associated with the viewing space is calculated/estimated as a function of the direction with which the surgical instrument reached the limit of the viewing space.

8. A method according to claim 3 and/or claim 4, wherein said safety volume (VS) comprises said cylinder or tubular volume, defined along the longitudinal axis of the surgical instrument, so as to allow the surgical instrument to move only along the dominant axis of the surgical instrument or therearound, when the surgical instrument is outside the viewing space (FOV).

9. A method according to claim 3 and/or claim 4, wherein said safety volume (VS) comprises said convex polytope, and wherein the movement of the surgical instrument upon exiting the viewing space and outside it is not allowed while approaching the surgical work surface in a direction (Z) perpendicular to the surgical work surface (XY).

10. A method according to any one of claims 1 -9, wherein said viewing space is defined by a field of view (FOV) of the viewing means, and wherein the step of controlling the movement of the slave device in a manner dependent on the determined position of the surgical instrument (170) comprises allowing the movement of the surgical instrument (170), in a normal operating mode, when the surgical instrument (170) is inside said field of view (FOV).

11. A method according to any one of claims 1 -10, wherein said step of defining a safety volume (VS) comprises calculating said safety volume (VS) by means of one or more Computer Vision algorithms operating in real time based on digital data derived from the viewing means.

12. A method according to any one of claims 2-10, wherein said step of defining a safety volume (VS) comprises calculating said safety volume (VS) by means of one or more Computer Vision algorithms operating on digital data derived from second viewing means having a second field of view (FOV2) or based on digital data/images recorded in a pre-operation phase.

13. A method according to claims 2-9, wherein the safety volume is defined as a volume surrounding the viewing space, from which sub-volumes or non-penetrating subareas, in which the movement of the surgical instrument is not allowed, are excluded.

14. A method according to any one of claims 2-9, wherein said step of defining a safety volume (VS) comprises calculating said safety volume (VS) as a volumetric extension of the viewing space, and/or based on kinematic or mechanical information of the robotic system and/or slave device.

15. A method according to any one of claims 1 -14, wherein said step of defining a safety volume (VS) comprises:

- recording the exit point and the exit orientation of the surgical instrument from the viewing space, based on digital data or on the image provided by the viewing means, and expressing said exit point and exit orientation in terms of coordinates referring to a coordinate system of the slave workspace;

- calculating or defining said safety volume (VS) based on said exit point and exit orientation of the surgical instrument from the viewing space.

16. A method according to any one of claims 1 -15, wherein said step of determining a position of the surgical instrument (170) comprises determining a current position of the surgical instrument (170) and/or the presence of the surgical instrument (170) in the viewing space based on digital data deriving from the viewing means.

17. A method according to any one of claims 1 -16, wherein said step of determining a position of the surgical instrument (170) comprises:

- mapping said viewing space in a corresponding slave field-of-view workspace, in a slave reference coordinate system associated with the slave device;

- determining the position of the surgical instrument (170) in terms of respective position coordinates in said slave reference coordinate system;

- determining the position of the surgical instrument (170) with respect to the viewing space based on a comparison between said position coordinates and said slave field-of-view workspace, in the slave reference coordinate system.

18. A method according to claim 17, further comprising the steps of:

- defining, in the slave reference coordinate (SFO) system, a slave kinematic workspace (175), based on physical movement limits of the slave device and/or operating constraints not correlated to the viewing means;

- defining, in the slave reference coordinate system, an actual slave workspace (200), corresponding to the intersection of said slave field-of-view (FOV) workspace and slave kinematic workspace (175); and wherein the step of controlling the slave device movement comprises controlling the slave device movement so that the movement of the surgical instrument (170) is allowed if the surgical instrument (170) is inside said actual slave workspace (200).

19. A method according to any one of claims 16-18, wherein said step of determining a position of the surgical instrument (170) is carried out cyclically and/or continuously in real time, to verify the position or presence of the surgical instrument (170) in the viewing space or actual slave workspace (200) in real time.

20. A method according to any one of claims 16-18, wherein said step of determining a position of the surgical instrument (170) comprises:

- calculating and/or determining the position of a real point belonging to the surgical instrument or the position of a virtual point integral with the surgical instrument (170), and/or

- calculating and/or determining the position of a virtual control point (600) of the slave device, and/or

- determining the position of at least one of the tips (171 , 172) of the surgical instrument (170), and/or

- determining the position of at least one of the links of a hinged wrist (177) included in the surgical instrument (170), and/or

- determining the position of a distal portion of a positioning shaft (179) close to the hinged wrist (177) of the surgical instrument (170).

21. A method according to claim 10 and claim 18, wherein the viewing space comprises said field of view (FOV) of the viewing means, or a predefined subset of the field of view (FOV), or said field-of-view (FOV) workspace, or said actual slave workspace (200), comprising the further step of defining the limits or edges of the viewing space which in turn define upper and lower thresholds for the allowed movements of the slave device.

22. A method according to claim 21 , wherein said limits or edges comprise a threshold perimeter on a plane (XY) orthogonal to a depth direction (Z) of the field of view (FOV), wherein said threshold perimeter defines upper/lower thresholds for movements in said plane (XY) and/or along orthogonal axes (X, Y) belonging to the plane (XY), wherein said threshold perimeter is calculated depending on the distance of the plane (XY) with respect to the viewing means.

23. A method according to claim 22, wherein said limits or edges also comprise, in addition to the threshold perimeter on a plane (XY), lower/upper thresholds along the axis of the depth direction (Z) of the field of view (FOV), wherein said lower/upper thresholds along the axis of the depth direction (Z) are determined based on a good focusing of the viewing means, evaluated and calculated in real time using data provided by the viewing means, or based on the field depth of the viewing means in a given configuration.

24. A method according to any one of the preceding claims, wherein said step of controlling the slave device movement comprises:

- allowing the surgical instrument (170) to exit the viewing space and/or a field- of-view (FOV) space and/or viewing space limits;

- allowing the movement of the surgical instrument (170), in a limited operating mode, if it is outside the viewing space but inside the safety volume (VS), maintaining a teleoperation state;

- not allowing the movement of the surgical instrument (170) if it is outside both the viewing space and the safety volume (VS);

- allowing the surgical instrument (170) to return from the safety volume (VS) to the viewing space and/or field-of-view (FOV) space and/or within the viewing space limits, maintaining a teleoperation state.

25. A method according to claim 24, wherein said step of allowing the movement of the surgical instrument (170) in a limited operating mode comprises: - controlling the slave device so that it moves with a limited or reduced speed, less than the maximum speed that is achievable and/or allowed when the slave device is inside the viewing space; and/or

- controlling the slave device so that it moves with a scale factor, between master device and slave device, which is increased with respect to the scale factor provided inside the viewing space.

26. A method according to claim 24 or claim 25, wherein said step of allowing the movement of the surgical instrument (170) in a limited operating mode comprises:

- if the surgical instrument reaches the edge or limit of the safety volume (VS), allowing a movement of the surgical instrument only along the edge or limit of the safety volume (VS), or temporarily blocking the surgical instrument at the point in which it reached said edge or limit.

27. A method according to any one of claims 24-26, wherein said step of allowing the movement of the surgical instrument (170) in a limited operating mode comprises: constraining or inhibiting one or more degrees of freedom of the surgical instrument (170).

28. A method according to any one of claims 24-27, wherein said step of allowing the surgical instrument (170) to return from the safety volume (VS) to the viewing space comprises:

- discriminating an exiting and/or distancing phase of the surgical instrument (170) from the viewing space, wherein the distance of the surgical instrument from the edge of the viewing space increases and wherein said safety volume (VS) is an exit safety volume calculated in relation to the exiting and/or distancing phase, from a returning phase of the surgical instrument (170) towards and into the viewing space, wherein the distance of the surgical instrument from the edge of the viewing space decreases;

- controlling the movement of the surgical instrument (170) so that it remains within said return safety volume during the returning phase.

29. A method according to claim 28, wherein said return safety volume comprises a containment volume including all the coordinates traveled by the surgical instrument (170) during the exiting and distancing phase, for example a containment cone trunk or another containment geometric figure, and wherein controlling the movement of the surgical instrument (170) during the returning phase comprises: constraining the surgical instrument (170) to stay inside the return safety volume through a translation limitation or a speed limitation, wherein the return speed is less than the exit speed.

30. A method according to any one of the preceding claims, comprising keeping the robotic system and the slave device in a teleoperation state, if and when the surgical instrument (170) is inside the viewing space or the safety volume (VS).

31. A method according to any one of claims 1 -29, comprising the step of stopping the teleoperation of the robotic system, or exiting a teleoperating condition of the robotic system, if and when the surgical instrument (170) exits the safety volume being thus outside both the safety volume and the viewing space.

32. A method according to any one of the preceding claims, comprising the further step of:

- allowing and/or enabling alignment operations between the master device (110) and the slave device (170) and/or allowing an entry into teleoperation even when the surgical instrument (170) is outside the viewing space but only if it is inside the safety volume (VS), or upon an exit from the teleoperation phase to reach the edge or limit of the safety volume (VS).

33. A method according to any one of the preceding claims, wherein the robotic system comprises a plurality of slave devices and respective surgical instruments, and wherein the steps of the method are carried out for each of the slave devices and respective surgical instruments.

34. A method according to any one of the preceding claims, further comprising providing the operator with visual and/or auditory and/or haptic alerts when the device is close to the limits or edges of the viewing space and/or when the device is close to the limits or edges of the safety volume (VS).

35. A method according to any one of the preceding claims, further comprising providing activation means, for example a pedal, which, when actuated by an operator of the robotic system, allow the movement of the surgical instrument outside the viewing space or the safety volume.

36. A method according to any one of the preceding claims, further comprising providing on-screen visual elements to guide an operator while performing the return of the surgical instrument (170) to the viewing space, or to inform the operator about the exit of the surgical instrument (170) from the viewing space.

37. A robotic system (100) for medical or surgical teleoperation, comprising:

- at least one master device (110) adapted to be moved by an operator (150);

- at least one slave device comprising a surgical instrument (170) adapted to be controlled by the master device;

- viewing means configured to display to the operator (150) images and/or videos of a viewing space associated with a teleoperation area in which the surgical instrument (170) operates,

- a control unit configured to control the slave device, during a teleoperation, based on master device movements, wherein the control unit is further configured to:

- define a safety volume (VS), included in the slave workspace but outside the viewing space, in accordance with the criterion that a safety level of the movement of the surgical instrument (170) is ensured in the safety volume (SF) limiting or eliminating risks of contact of the surgical instrument (170) with anatomical parts of a patient or elements supporting the surgical activity;

38. A robotic system according to claim 37, wherein said safety volume (VS) is defined:

39. A robotic system according to claim 38, wherein said safety volume (VS) comprises:

40. A robotic system according to claim 38 or claim 39, wherein the safety volume (VS) is dynamically defined, during a teleoperation, depending on the most recent exit point, determined or recorded, of the surgical instrument (170) from the viewing space.

41. A robotic system according to claim 39 and/or claim 40, wherein said safety volume (VS) comprises said external surroundings of the viewing space, and said spatial tolerance (e) is a predefined constant value, or a dynamically variable value, defined as a function of the speed of the surgical instrument (170) upon exiting the viewing space, or as a function of a scale factor between the movement of the master device and the consequent movement of the slave device.

42. A robotic system according to claim 39 and/or claim 40, wherein said safety volume (VS) comprises said cone or cone trunk, having a height and an angular opening around the exit direction of the surgical instrument from the viewing space, wherein said height and said angular opening depend on the exit speed of the surgical instrument (170) from the viewing space, or depend on a scale factor between the movement of the master device and the consequent movement of the slave device, or depend on other kinematic parameters of the robotic system.

43. A robotic system according to claim 42, wherein the angular opening is inversely proportional to the exit speed or directly proportional to the scale factor, and the height H is directly/inversely proportional to the exit speed or directly/inversely proportional to the scale factor, and/or wherein the angular opening of the cone with respect to coordinates associated with the viewing space is calculated/estimated as a function of the direction with which the surgical instrument reached the limit of the viewing space.

44. A robotic system according to claim 39 and/or claim 40, wherein said safety volume (VS) comprises said cylinder or tubular volume, defined along the longitudinal axis of the surgical instrument, so as to allow the surgical instrument to move only along the dominant axis of the surgical instrument or therearound, when the surgical instrument is outside the viewing space (FOV).

45. A robotic system according to claim 39 and/or claim 40, wherein said safety volume (VS) comprises said convex polytope, and wherein the movement of the surgical instrument upon exiting the viewing space and outside it is not allowed while approaching the surgical work surface in a direction (Z) perpendicular to the surgical work surface (XY).

46. A robotic system according to any one of claims 37-45, wherein said viewing space is defined by a field of view (FOV) of the viewing means, and wherein the step of controlling the movement of the slave device in a manner dependent on the determined position of the surgical instrument (170) comprises allowing the movement of the surgical instrument (170), in a normal operating mode, when the surgical instrument (170) is inside said field of view (FOV).

47. A robotic system according to any one of claims 37-46, wherein said action of defining a safety volume (VS) comprises calculating said safety volume (VS) by means of one or more Computer Vision algorithms operating in real time based on digital data derived from the viewing means.

48. A robotic system according to any one of claims 38-46, wherein said action of defining a safety volume (VS) comprises calculating said safety volume (VS) by means of one or more Computer Vision algorithms operating on digital data derived from second viewing means having a second field of view (FOV2) or based on digital data/images recorded in a pre-operation phase.

49. A robotic system according to claims 38-45, wherein the safety volume is defined as a volume surrounding the viewing space, from which sub-volumes or nonpenetrating sub-areas, in which the movement of the surgical instrument is not allowed, are excluded.

50. A robotic system according to any one of claims 38-45, wherein said action of defining a safety volume (VS) comprises calculating said safety volume (VS) as a volumetric extension of the viewing space, and/or based on kinematic or mechanical information of the robotic system and/or slave device.

51. A robotic system according to any one of claims 37-50, wherein said action of defining a safety volume (VS) comprises:

- recording the exit point and the exit orientation of the surgical instrument from the viewing space, based on digital data or on the provided image of the viewing means, and expressing said exit point and exit orientation in terms of coordinates referring to a coordinate system of the slave workspace;

52. A robotic system according to any one of claims 37-51 , wherein said action of determining a position of the surgical instrument (170) comprises determining a current position of the surgical instrument (170) and/or the presence of the surgical instrument (170) in the viewing space based on digital data deriving from the viewing means.

53. A robotic system according to any one of claims 37-52, wherein said action of determining a position of the surgical instrument (170) comprises:

54. A robotic system according to claim 53, wherein the control unit is further configured to carry out the actions of:

- defining, in the slave reference coordinate system, an actual slave workspace (200), corresponding to the intersection of said slave field-of-view (FOV) workspace and slave kinematic workspace (175); and wherein the action of controlling the slave device movement comprises controlling the slave device movement so that the movement of the surgical instrument (170) is allowed if the surgical instrument (170) is inside said actual slave workspace (200).

55. A robotic system according to any one of claims 52-54, wherein said action of determining a position of the surgical instrument (170) is carried out cyclically and/or continuously in real time, to verify the position or presence of the surgical instrument (170) in the viewing space or actual slave workspace (200) in real time.

56. A robotic system according to any one of claims 53-54, wherein said action of determining a position of the surgical instrument (170) comprises:

57. A robotic system according to claim 46 and claim 54, wherein the viewing space comprises said field of view (FOV) of the viewing means, or a predefined subset of the field of view (FOV), or said field-of-view (FOV) workspace, or said actual slave workspace (200), wherein the control unit is further configured to carry out the further action of defining the limits or edges of the viewing space which in turn define upper and lower thresholds for the allowed movements of the slave device.

58. A robotic system according to claim 57, wherein said limits or edges comprise a threshold perimeter on a plane (XY) orthogonal to a depth direction (Z) of the field of view (FOV), wherein said threshold perimeter defines upper/lower thresholds for movements in said plane (XY) and/or along orthogonal axes (X, Y) belonging to the plane (XY), wherein said threshold perimeter is calculated depending on the distance of the plane (XY) with respect to the viewing means.

59. A robotic system according to claim 58, wherein said limits or edges comprise, in addition to the threshold perimeter on a plane (XY), also lower/upper thresholds along the axis of the depth direction (Z) of the field of view (FOV), wherein said lower/upper thresholds along the axis of the depth direction (Z) are determined based on a good focusing of the viewing means, evaluated and calculated in real time using data provided by the viewing means, or based on the field depth of the viewing means in a given configuration.

60. A robotic system according to any one of claims 37-59, wherein said action of controlling the slave device movement comprises:

61. A robotic system according to claim 60, wherein said action of allowing the movement of the surgical instrument (170) in a limited operating mode comprises:

- controlling the slave device so that it moves with a limited or reduced speed, less than the maximum speed that is achievable and/or allowed when the slave device is inside the viewing space; and/or

62. A robotic system according to claim 60 or claim 61 , wherein said action of allowing the movement of the surgical instrument (170) in a limited operating mode comprises:

63. A robotic system according to any one of claims 60-62, wherein said action of allowing the movement of the surgical instrument (170) in a limited operating mode comprises constraining or inhibiting one or more degrees of freedom of the surgical instrument (170).

64. A robotic system according to any one of claims 60-63, wherein said action of allowing the surgical instrument (170) to return from the safety volume (VS) to the viewing space comprises:

65. A robotic system according to claim 64, wherein said return safety volume comprises a containment volume including all the coordinates traveled by the surgical instrument (170) during the exiting and distancing phase, for example a containment cone trunk or another containment geometric figure, and wherein the action of controlling the movement of the surgical instrument (170) during the returning phase comprises: constraining the surgical instrument (170) to stay inside the return safety volume through a translation limitation or a speed limitation, wherein the return speed is less than the exit speed.

66. A robotic system according to any one of claims 37-65, wherein the control unit is further configured for keeping the robotic system and the slave device in a teleoperation state, if and when the surgical instrument (170) is inside the viewing space or the safety volume (VS).

67. A robotic system according to any one of claims 37-65, wherein the control unit is further configured to carry out the action of:

- stopping the teleoperation of the robotic system, or exiting a teleoperating condition of the robotic system, if and when the surgical instrument (170) exits the safety volume being thus outside both the safety volume and the viewing space.

68. A robotic system according to any one of claims 37-67, wherein the control unit is further configured to carry out the further action of:

69. A robotic system according to any one of claims 37-68, wherein the robotic system comprises a plurality of slave devices and respective surgical instruments, and wherein said actions are carried out for each of the slave devices and respective surgical instruments.

70. A robotic system according to any one of claims 37-69, wherein the control unit is further configured for providing the operator with visual and/or auditory and/or haptic alerts when the device is close to the limits or edges of the viewing space and/or when the device is close to the limits or edges of the safety volume (VS).

71. A robotic system according to any one of claims 37-70, wherein the control unit is further configured for providing activation means, for example a pedal, which, when actuated by an operator of the robotic system, allow the movement of the surgical instrument outside the viewing space or the safety volume.

72. A robotic system according to any one of claims 37-71 , wherein the control unit is further configured for providing on-screen visual elements to guide an operator while performing the return of the surgical instrument (170) to the viewing space, or to inform the operator about the exit of the surgical instrument (170) from the viewing space.