REPOSITIONING METHOD OF INPUT DEVICE FOR ROBOTIC SURGICAL SYSTEM

Abstract

A robotic surgical system includes a linkage, an input handle, and a processing unit. The linkage moveably supports a surgical tool relative to a base. The input handle is moveable in a plurality of directions. The processing unit is in communication with the input handle and is operatively associated with the linkage to move the surgical tool based on a scaled movement of the input handle. The scaling varies depending on whether the input handle is moved towards a center of a workspace or away from the center of the workspace. The workspace represents a movement range of the input handle.

Claims

1. (canceled)

2. A robotic surgical system comprising: a first linkage moveably supporting a surgical tool relative to a base and an input handle moveable in a plurality of directions; a second linkage moveably supporting an imaging device relative to the base, the imaging device being configured to capture the surgical tool; and a processing unit in communication with the input handle operatively associated with the first linkage to move the surgical tool based on a scaled movement of the input handle, and, with the imaging device operatively associated with the second linkage, to move the imaging device, wherein the processing unit is configured to: determine a location of the imaging device relative to a workspace, which represents a movement range of the surgical tool; vary a scaling factor based on the location; and scale a movement of the input handle based on the scaling factor.

3. The robotic surgical system of claim 2, wherein the imaging device is a three-dimensional camera.

4. The robotic surgical system of claim 3, further comprising: a display configured to display the workspace in three-dimensions.

5. The robotic surgical system of claim 2, wherein the imaging device moves in six degrees of freedom.

6. The robotic surgical system of claim 2, wherein the scaling factor is linearly varied based on the location and a limit of movement of the input handle.

7. The robotic surgical system of claim 2, wherein the scaling factor is exponentially varied based on the location and a limit of movement of the input handle.

8. The robotic surgical system of claim 2, wherein the location is based on an anti-gravity direction with respect to the workspace.

9. The robotic surgical system of claim 2, further comprising: a switch operably connected to the processing unit and configured to switch between a run mode and a camera mode.

10. The robotic surgical system of claim 9, wherein the surgical tool is moved by the input handle in the run mode.

11. The robotic surgical system of claim 9, wherein the imaging device is moved by the input handle in the camera mode.

12. A robotic surgical system comprising: a first linkage moveably supporting a surgical tool relative to a base and an input handle moveable in a plurality of directions; a second linkage moveably supporting an imaging device relative to the base, the imaging device being configured to capture the surgical tool; and a processing unit in communication with the input handle operatively associated with the first linkage to move the surgical tool based on a scaled movement of the input handle, and with the imaging device operatively associated with the second linkage to move the imaging device, wherein the processing unit is configured to: determine a location of the imaging device relative to a workspace, which represents a movement range of the surgical tool; vary a scaling factor based on the location; and zoom the imaging device in or out from the workspace as the scaling factor is increased decreased.

13. A method of operating a robotic surgical system, the method comprising: detecting a plurality of movements of an input handle of the robotic surgical system; determining a location of an imaging device, which is supported by a second linkage of the robotic surgical system, relative to a workspace, which represents a movement range of a surgical tool of the robotic surgical system; varying a scaling factor based on the location of the imaging device; and scaling a detected movement of the input handle based on the scaling factor.

14. The method of claim 13, further comprising capturing a three-dimensional image using the imaging device.

15. The method of claim 13, further comprising: displaying the workspace in three-dimensions.

16. The method of claim 13, wherein varying a scaling factor based on the location of the imaging device includes varying the scaling factor based on an anti-gravity direction with respect to the workspace.

17. The method of claim 13, further comprising linearly varying the scaling factor based on the location and a limit of movement of the input handle.

18. The method of claim 13, further comprising exponentially varying the scaling factor based on the location and a limit of movement of the input handle.

19. The method of claim 13, further comprising: switching between a run mode and a camera mode based on a user's selection.

20. The method of claim 19, further comprising: moving the imaging device based on the scaled movement of the input handle in the camera mode.

21. The method of claim 19, further comprising: moving the surgical tool based on the scaled movement of the input handle in the run mode.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Various aspects of the present disclosure are described hereinbelow with reference to the drawings, which are incorporated in and constitute a part of this specification, wherein:

[0041] FIG. 1 is a schematic illustration of a user interface and a robotic system in accordance with the present disclosure;

[0042] FIG. 2 is a plan view of an arm of the user interface of FIG. 1 within a two-dimensional workspace;

[0043] FIG. 3 is a plan view of a workspace of the user interface of FIG. 1; and

[0044] FIG. 4 is a schematic of a method for scaling movement of a user interface in accordance with the present disclosure.

DETAILED DESCRIPTION

[0045] Embodiments of the present disclosure are now described in detail with reference to the drawings in which like reference numerals designate identical or corresponding elements in each of the several views. As used herein, the term “clinician” refers to a doctor, a nurse, or any other care provider and may include support personnel. Throughout this description, the term “proximal” refers to the portion of the device or component thereof that is closest to the clinician and the term “distal” refers to the portion of the device or component thereof that is farthest from the clinician.

[0046] Referring to FIG. 1, a robotic surgical system 1 in accordance with the present disclosure is shown generally as a robotic system 10, a processing unit 30, and a user interface 40. The robotic system 10 generally includes linkages 12 and a robot base 18. The linkages 12 moveably support an end effector or tool 20 which is configured to act on tissue. The linkages 12 may be in the form of arms each having an end 14 that supports an end effector or tool 20 which is configured to act on tissue. In addition, the ends 14 of the arms 12 may include an imaging device 16 for imaging a surgical site “S”. The user interface 40 is in communication with robot base 18 through the processing unit 30.

[0047] The user interface 40 includes a display device 44 which is configured to display three-dimensional images. The display device 44 displays three-dimensional images of the surgical site “S” which may include data captured by imaging devices 16 positioned on the ends 14 of the arms 12 and/or include data captured by imaging devices that are positioned about the surgical theater (e.g., an imaging device positioned within the surgical site “S”, an imaging device positioned adjacent the patient “P”, imaging device 56 positioned at a distal end of an imaging arm 52). The imaging devices (e.g., imaging devices 16, 56) may capture visual images, infra-red images, ultrasound images, X-ray images, thermal images, and/or any other known real-time images of the surgical site “S”. The imaging devices transmit captured imaging data to the processing unit 30 which creates three-dimensional images of the surgical site “S” in real-time from the imaging data and transmits the three-dimensional images to the display device 44 for display.

[0048] The user interface 40 also includes input handles 42 which allow a clinician to manipulate the robotic system 10 (e.g., move the arms 12, the ends 14 of the arms 12, and/or the tools 20). Each of the input handles 42 is in communication with the processing unit 30 to transmit control signals thereto and to receive feedback signals therefrom. Additionally or alternatively, each of the input handles 42 may include control interfaces (not shown) which allow the surgeon to manipulate (e.g., clamp, grasp, fire, open, close, rotate, thrust, slice, etc.) the tools 20 supported at the ends 14 of the arms 12.

[0049] With additional reference to FIG. 2, each of the input handles 42 is moveable through a predefined workspace “W” to move the ends 14 of the arms 12 within a surgical site “S”. It will be appreciated that while the workspace “W” is shown in two-dimensions in FIG. 2 that the workspace “W” is a three-dimensional workspace. The three-dimensional images on the display device 44 are orientated such that the movement of the input handle 42 moves the ends 14 of the arms 12 as viewed on the display device 44. It will be appreciated that the orientation of the three-dimensional images on the display device may be mirrored or rotated relative to view from above the patient “P”. In addition, it will be appreciated that the size of the three-dimensional images on the display device 44 may be scaled to be larger or smaller than the actual structures of the surgical site permitting the surgeon to have a better view of structures within the surgical site “S”. As the input handles 42 are moved, the tools 20 are moved within the surgical site “S” as detailed below. As detailed herein, movement of the tools 20 may also include movement of the ends 14 of the arms 12 which support the tools 20.

[0050] For a detailed discussion of the construction and operation of a robotic surgical system 1, reference may be made to U.S. Patent Publication No. 2012/0116416, entitled “Medical Workstation”, the entire contents of which are incorporated herein by reference.

[0051] The movement of the tools 20 is scaled relative to the movement of the input handles 42. When the input handles 42 are moved within a predefined workspace “W”, the input handles 42 send control signals to the processing unit 30. The processing unit 30 analyzes the control signals to move the tools 20 in response to the control signals. The processing unit 30 transmits scaled control signals to the robot base 18 to move the tools 20 in response the movement of the input handles 42. The processing unit 30 scales the control signals by dividing an Input.sub.distance (e.g., the distance moved by one of the input handles 42) by a scaling factor S.sub.F to arrive at a scaled Output.sub.distance (e.g., the distance that one of the ends 14 is moved). The scaling factor S.sub.F is in a range between about 1 and about 10 (e.g., 3). This scaling is represented by the following equation:

Output.sub.distance=Input.sub.distance/S.sub.F.

It will be appreciated that the larger the scaling factor S.sub.f. the smaller the movement of the tools 20 relative to the movement of the input handles 42.

[0052] During a surgical procedure, if the clinician reaches the edge or limit of the predefined range of motion of an input handle 42, the clinician must clutch the input handle 42 (i.e., decouple the motion of the input handle 42 from the motion of the tool 20 of the respective arm 12) to reposition the input handle 42 back within the predefined workspace “W” before continuing to move the input handle 42 in the same direction. As the scaling factor S.sub.F is increased, the clinician may be required to clutch the input handle 42 more frequently, which increases the number of steps and thus, the time and/or costs of the surgical procedure.

[0053] In addition, when the input handle 42 is clutched from the tool 20, the orientation (e.g., roll, pitch, and yaw) of the tool 20 is also decoupled from the orientation of the input handle 42. When the input handle 42 is declutched or decoupled, the processing unit 30 may be programmed to align the orientation of the tool 20 with the orientation of the input handle 42, which may result in unintended movement of the tool 20 when the input handle 42 is recoupled. Alternatively, when the input handle 42 is reclutched or recoupled, the processing unit 30 may recalibrate the orientation of the input handle 42 when it is recoupled to the current orientation of the processing unit 30, which may result in the orientation of the input handle 42 being misrepresented by the tool 20.

[0054] To reduce or eliminate the need for a clinician to clutch the input handles 42 during a surgical procedure, each of the input handles 42 may include a repositioning control 43 that sends a signal to the processing unit 30 to switch the scaling factor S.sub.F between a procedural scaling factor PS.sub.F and a repositioning scaling factor RS.sub.F. The procedural scaling factor PS.sub.F is in a range of about 1.0 to about 10.0 (e.g., 3.0) and the repositioning scaling factor RS.sub.F is significantly larger in a range of about 100.0 to about 1000.0 (e.g., 500.0). The two scaling factors allow a clinician to perform a surgical procedure using the procedural scaling factor PS.sub.F and when one of the input handles 42 approaches an edge or a limit of movement of the predefined workspace “W”, the clinician activates the repositioning control 43 to change to the repositioning scaling factor RS.sub.F to move the input handle 42 to a desired position within the predefined workspace “W” without clutching the input handle 42. Once the input handle 42 is at the desired position within the predefined workspace “W”, the clinician deactivates the repositioning control 43 to switch back to the procedural scaling factor PS.sub.F to continue the surgical procedure. It will be appreciated that by activating and deactivating the repositioning control 43, to reposition the input handle 42 within the predefined workspace “W”, the orientational relationship between the input handle 42 and the end 14 of the arm 12 is maintained. It is contemplated a repositioning control 43 on each input handle 42 is activatable independent of a repositioning control 43 on another input handle 42. While the repositioning control 43 is represented as a button, it is contemplated that the repositioning control 43 may be operated by, but not limited to, a switch, a lever, a trigger, an optical sensor, or a voice command.

[0055] Additionally or alternatively, the processing unit 30 may vary the scaling factor S.sub.F based on the direction of movement of the input handle 42 within the predefined workspace “W” to keep the input handle 42 substantially centered within the predefined workspace “W”. As detailed below with reference to FIGS. 2-4, a method 300 of varying the scaling factor S.sub.F based on the direction of movement of the input handle 42 is detailed with respect to the “X” axis; however, it will be appreciated that this method 300 may be applied to each of the “X”, “Y”, and “Z” axes of the predefined workspace “W”. When the input handle 42 is moved away from a center “C” (Step 330), of the predefined workspace “W”, towards a limit of movement of the predefined workspace “W”, the processing unit 30 assigns a first scaling factor S.sub.F1 to the movement of the input handle 42, records the direction of movement represented by arrow “A”, and identifies the limit of movement represented by the border of the workspace “W”. When the input handle 42 is moved towards the center “C” of the predefined workspace “W” (Step 335), the processing unit 30 assigns a second scaling factor S.sub.F2 to the movement of the input handle 42 that is larger than the first scaling factor S.sub.F1, and records the direction of movement represented by arrow “B”. For example, the first scaling factor S.sub.F1 may be about 3.0 and the second scaling factor S.sub.F2 may be about 4.5. It is contemplated that first scaling factor S.sub.F1 may be about 0.70 to about 1.4 times the size of the second scaling factor S.sub.F2. Varying the scaling factor S.sub.F in this manner keeps the input handle 42 substantially centered by requiring the clinician to move the input handle 42 a greater distance when moving the input handle 42 towards the center “C” of the predefined workspace “W” as compared to the distance that the clinician moved the input handle 42 away from the center “C” to move the tool 20 the same distance in each direction.

[0056] Accordingly, the center “C” of the predefined workspace “W” continually shifts relative to the surgical site “S” (FIG. 1) during the surgical procedure. It is contemplated that the shifting of the center “C” of the predefined workspace “W” relative to the surgical site “S” may be imperceptible to the clinician. With particular reference to FIG. 3, it will be appreciated that as detailed above, the direction of arrow “A” is representative of the direction of movement of the input handle 42 away from the center “C” towards a point “F”; however, when the input handle 42 is moved from the center “C” towards a point “H”, the arrow “B” is representative of movement away from the center “C”. In embodiments, the first and second scaling factors S.sub.F1, S.sub.F2 are the same in each axis (e.g., the “X”, “Y”, and “Z” axes). In some embodiments, the first and second scaling factor S.sub.F1, S.sub.F2 in one axis (e.g., the “X” axis) is different from the first and second scaling factors S.sub.F1, S.sub.F2 in the other axes (e.g., the “Y” and “Z” axes).

[0057] With continued reference to FIGS. 2-4, the method may include the processing unit 30 varying the first and second scaling factors S.sub.F1, S.sub.F2 based on the location of the input handle 42 within the predefined workspace “W” (Steps 350, 355). As detailed below, the method of varying a scaling factor S.sub.F based on the location of the input handle 42 is detailed with respect to the “X” axis; however, it will be appreciated that this method may be applied to each of the “X”, “Y”, and “Z” axes of the predefined workspace “W”. Specifically, the scaling factors S.sub.F1, S.sub.F2 are implemented by differentiating the movement of the input handle 42 to calculate a handle velocity. This handle velocity is multiplied by the scaling factor (e.g., scaling factors S.sub.F1, S.sub.F2). This scaled velocity is then integrated with the current position of the tool 20 to determine a new position of the tool 20 such that movement of the tool 20 is smooth. The scaled velocity is continuously integrated such that the movement of the tool 20 is smooth even if the scaling factor is varied (e.g., when the scaling factor is smoothly or discreetly varied as detailed below).

[0058] In accordance with this method and represented as Steps 345 and 355, the second scaling factor S.sub.F2 may increase as the location of the input handle 42 moves away from the center “C” of the predefined workspace “W” (e.g., the second scaling factor S.sub.F2 may be larger when the input handle 42 is at point “D” than when the input handle 42 is at center “C”, the second scaling factor S.sub.F2 may be larger when the input handle 42 is at point “E” than when the input handle 42 is at point “D”, and the second scaling factor S.sub.F2 may be larger when the input handle 42 is at point “F” than when the input handle 42 is at point “E”). For example, the second scaling factor S.sub.F2 may vary in a linear manner based on the location of the input handle 42 from the center “C” such that at point “F” the second scaling factor S.sub.F2 is about 4.5, at point “E” the second scaling factor S.sub.F2 is about 4.0, at point “D” the second scaling factor S.sub.F2 is about 3.5, and at center “C” the second scaling factor S.sub.F2 is about 3.0.

[0059] Alternatively, the second scaling factor S.sub.F2 may vary as a function of the location of the input handle 42 from the center “C”. For example, the second scaling factor S.sub.F2 may vary in an exponential manner based on the location of the input handle 42 from the center “C” such that at point “F” the second scaling factor S.sub.F2 is about 6.5, at point “E” the second scaling factor S.sub.F2 is about 4.5, at point “D” the second scaling factor S.sub.F2 is about 3.5, and at the center “C” the second scaling factor S.sub.F2 is about 3.0.

[0060] In addition, it is contemplated that the second scaling factor S.sub.F2 may be constant as the input handle 42 is within a first section Si close to the center “C” and linearly or exponentially increase as the location of the input handle 42 is moved away from the center “C” beyond the first section Si.

[0061] It is within the scope of this disclosure that the second scaling factor S.sub.F2 may increase, in a relatively smooth manner, as the location of the input handle 42 away from the center “C” based on a linear or exponential formula or that the second scaling factor S.sub.F2 may change discretely at each of a plurality of points (e.g., points “D”, “E”, and “F”) creating discontinuities in the second scaling factor S.sub.F2.

[0062] As detailed above, increasing the second scaling factor S.sub.F2 requires the clinician to move the input handle 42 a greater distance towards the center “C” when compared to movement of the input handle 42 away from the center “C” to move the tool 20 an equal distance in each direction as the location of the input handle 42 away from the center “C” increases, which shifts the center “C” relative to the surgical site “S” to reduce or eliminate the need to clutch the input handle 42.

[0063] In addition as represented in steps 340 and 350, the first scaling factor S.sub.F1 may decrease as the location of the input handle 42 moves away from the center “C” of the predefined workspace “W” (e.g., the first scaling factor S.sub.F1 may be smaller when the input handle 42 is at point “D” than when the input handle 42 is at the center “C”, the first scaling factor S.sub.F1 may be smaller when the input handle 42 is at point “E” than when the input handle 42 is at point “D”, and the first scaling factor S.sub.F1 may be smaller when the input handle 42 is at point “F” than when the input handle 42 is at point “E”). For example, the first scaling factor S.sub.F1 may vary in a linear manner based on the location of the input handle 42 from the center “C” such that at the center “C” the first scaling factor S.sub.F1 is about 3.0, at point “D” the first scaling factor S.sub.F1 is about 2.75, at point “E” the first scaling factor S.sub.F1 is about 2.5, and at point “F” the first scaling factor S.sub.F1 is about 2.25.

[0064] Alternatively, the first scaling factor S.sub.F1 may vary as a function of the location of the input handle 42 from the center “C”. For example, the first scaling factor S.sub.F1 may vary in an exponential manner based on the location of the input handle 42 from the center “C” such that at the center “C” the first scaling factor S.sub.F1 is about 3.0, at point “D” the first scaling factor S.sub.F1 is about 2.75, at point “E” the first scaling factor S.sub.F1 is about 2.25, and at point “F” the first scaling factor S.sub.F1 is about 1.25.

[0065] In addition, it is contemplated that the first scaling factor S.sub.F1 may be constant as the input handle 42 is at a location near the center “C” (e.g., when the input handle is between point “D” and a point “G” the first scaling factor S.sub.F1 is constant) and linearly or exponentially decreased as the location of the input handle 42 is moved beyond point “D” or point “G”. It is within the scope of this disclosure that the first scaling factor S.sub.F1 may increase, in a relatively smooth manner, as the location of the input handle 42 moves away from the center “C” based on a linear or exponential formula or that the first scaling factor S.sub.F1 may change discretely at each of a plurality of points (e.g., points “D”, “E”, and “F”) creating discontinuities in the first scaling factor S.sub.F1.

[0066] As detailed above, increasing the first scaling factor S.sub.F1 allows the clinician to move the input handle 42 a lesser distance away from the center “C” as the location of the input handle 42 away from the center “C” is increased to result in the same movement of the tool 20, which in turn shifts the center “C” relative to the surgical site “S” to reduce or eliminate the need to clutch the input handle 42.

[0067] It is contemplated that each input handle 42 may vary the respective scaling factors S.sub.F1, S.sub.F2 in a similar manner or may vary the respective scaling factors S.sub.F1, S.sub.F2 in differing manners (e.g., one input handle 42 may vary its scaling factors S.sub.F1, S.sub.F2 based on the location of the input handle 42 and another input handle 42 may vary its scaling factors S.sub.F1, S.sub.F2 based on the direction of movement of the another input handle relative to the center “C”, each input handle 42 may vary its scaling factors S.sub.F1, S.sub.F2 using different linear or exponential formulas). It is also contemplated that an input handle 42 may vary one of the scaling factors S.sub.F1, S.sub.F2 and the other of the scaling factors S.sub.F1, S.sub.F2 may be constant. While points “F” to “J” are shown spaced evenly apart, it is contemplated that points “F” to “J” may be spaced apart different distances from one another. For example, be spaced closer to one another as the points get closer to the limit of movement.

[0068] Referring back to FIG. 1, the robotic surgical system 1 includes an imaging arm 52 that is controlled by the processing unit 30 and may be selectively controlled by the user interface 40. The imaging arm 52 includes an imaging device 56 disposed on a distal end thereof. The imaging device 56 is located over or within the surgical site “S” and is configured to capture the tools 20 acting within the surgical site “S” of the patient “P” and transmit the captured images to the display 44. The imaging device 56 may be a three-dimensional (3D) camera and the display 44 may be a 3D display enabling the clinician to view the surgical site “S” in three dimensions. The imaging device 56 is moveable relative to or within the surgical site “S” in six degrees of freedom and may be selectively moved by one of the input handles 42. The surgical system 1 may include a foot switch (not shown) that switches one of the input handles 42 between a run mode where the input handle 42 is associated with one of the arms 12 to move the tool 20 within the surgical site “S” and a camera mode where the input handle 42 is associated with the imaging arm 52 to move the imaging device 56 about the surgical site “S”. It is also contemplated that one of the input handles 42 may include a camera button (not shown) to operatively associate the input handle 42 with the imaging arm 52.

[0069] The processing unit 30 may determine the location of the imaging device 56 relative to or within the surgical site “S” to determine the scaling factor S.sub.F used to associate the movement of the input handles 42 to the movement of the tools 20 within the surgical site “S”. As detailed herein, the processing unit 30 determines the location of the imaging device 56 relative to the surgical site “S” along the “Z” axis to determine the scaling factor S.sub.F; however, the processing unit 30 may determine the scaling factor S.sub.F based on the location of the imaging device 56 relative to or within the surgical site “S” in each of the “X”, “Y”, and “Z” axes.

[0070] With continued reference to FIG. 1, when the imaging device 56 is in a first position “L” the scaling factor S.sub.F has a first value and when the imaging device 56 is in a second position “M” the scaling factor S.sub.F has a second value larger than the first value. For example, the first value may be about “1” when the imaging device 56 is in the first position “L” and as the imaging device 56 is moved closer to the surgical site “S” to the second position “M”, the second value may be about “2”. Continued movement of the imaging device to a third location “N” may further increase the scaling factor S.sub.F to a third value (e.g., about 3). It will be appreciated that by increasing the scaling factor S.sub.F as the imaging device 56 is moved closer to the surgical site “S”, the movement of the tools 20 within the surgical site “S” relative to the movement of the input handles 42 within the predefined workspace “W” is decreased such that the movement of the tools 20 as shown on the display 44 is relatively constant for a movement of the input handles 42 within the predefined workspace “W”.

[0071] The processing unit 30 may be operatively associated with the imaging arm 52 such that as the scaling factor S.sub.F is increased or decreased the processing unit 30 zooms the imaging device 56 in and out from the surgical site “S” to match the movement of the input handles 42 within the predefined workspace “W” to the movement of the tools 20 within the surgical site “S” as viewed by the clinician on the display 44. The zooming in and out of the imaging device 56 may be accomplished by manipulating a lens assembly (not explicitly shown) of the imaging device 56 or by moving the imaging device 56 towards and away from the surgical site “S”. The processing unit 30 may zoom the imaging device 56 out when one of the input handles 42 approaches a limit or edge of the predefined workspace “W” to keep the tools 20 within the field of view of the imaging device 56. In addition, the processing unit 30 may reposition the imaging device 56 such that the center “C” (FIG. 2) of the input handles 42 are substantially centered on the display device 44.

[0072] It is contemplated that any of the methods of varying the scaling factor S.sub.F or moving of the imaging device 56 may be selectively activated or deactivated by a clinician operating the robotic surgical system 1 before or during a surgical procedure.

[0073] It will be appreciated that the scaling factor S.sub.F determined by the processing unit 30 based on the position of the imaging device 56 relative to the surgical site “S” may be varied as detailed above based on the movement of or location of the input handles 42 relative to the center “C” of the predefined workspace “W”.

[0074] While several embodiments of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Any combination of the above embodiments is also envisioned and is within the scope of the appended claims. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope of the claims appended hereto.