The present invention relates to the field of robot-assisted surgical systems and methods and, in particular, to a surgical robot, a control method, a system, and a readable storage medium.
Orthopedic surgical robots can effectively reduce damage to soft and bone tissues, bleeding and trauma, and are therefore more favorable to post-operative recovery of patients' knee joints. However, in robot-assisted surgical procedures, bone cutting areas are generally determined at surgeon's discretion. Consequently, for the same patient, different surgeons may get different results and outcomes, and operational errors may occur, leading to excessive removal of soft and bone tissues.
Therefore, for an orthopedic surgical robot, it is necessary to properly determine the boundary of a bone cutting area so that the robot can be effectively limited to move within a range corresponding to the boundary. Although there are existing solutions for limiting a range of movement of a robot, such solutions requires deriving a precise dynamic model for tactile devices, which is, however, difficult to achieve for surgical robots with sophisticated mechanisms. In particular, when under the influence of friction and other nonlinear factors, it is probable for surgeons to make incorrect determinations.
It is an object of the present invention to provide a surgical robot, a control method, a system, and a readable storage medium, which overcome the problem of difficult, inaccurate conventional boundary control for surgical robot, which tends to lead to operational errors.
The above object is attained by a control method for a surgical robot comprising a manipulation terminal proposed in a first aspect of the present invention, which comprises:
Optionally, the first feedback information may comprise commanded position and posture information for a joint in the manipulation terminal, and the second feedback information may comprise torque information of the external environmental force on the joint in the manipulation terminal.
Optionally, compensating the drive information applied by the surgical robot to the manipulation terminal may comprise:
Optionally, the external environmental force may comprise a resistance torque Fa of a surgical object to the manipulation terminal and a traction torque f applied by an operator to the manipulation terminal, wherein the equivalent torque F satisfy F=Fs+N+Fa+f and the torque Fc of the external environmental force satisfy Fc=F−Fs−N.
Optionally, the calculation performed by the position and posture controller may comprise:
Optionally, the commanded speed may be obtained by performing a differential calculation on the commanded position and posture.
Optionally, the first feedback information may comprise commanded position and posture information for the joint in the manipulation terminal, wherein the first feedback information comprises an impedance control model of the external environmental force over the joint in the manipulation terminal.
Optionally, compensating the drive information applied by the surgical robot to the manipulation terminal may comprise:
Optionally, an input to the impedance control model may be derived using a process comprising the steps of:
Optionally, the manipulation terminal may comprise a robotic arm and/or a manipulator, wherein the first feedback information comprises commanded position and posture information for a joint in the robotic arm and/or the manipulator, and wherein the manipulator is configured to fix a surgical instrument thereto and guide it to perform a surgical operation.
The above object is also attained by a readable storage medium proposed in a second aspect of the present invention, which stores a program thereon. When executed, the program implements a control method for a surgical robot as defined above.
The above object is also attained by a surgical robot proposition and postured in a third aspect of the present invention, which comprises a manipulation terminal. The manipulation terminal comprises a robotic arm and/or a manipulator for guiding a surgical instrument to perform a surgical operation. The manipulation terminal is controlled using a control method for a surgical robot as defined above.
The above object is also attained by a surgical robot system proposed in a fourth aspect of the present invention, which comprises a control device, a navigation device and a manipulation terminal. The navigation device is configured to track a current position and posture of the manipulation terminal and feed the position and posture information back to the control device. The control device is configured to control the manipulation terminal using a control method for a surgical robot as defined above.
Optionally, the manipulation terminal may comprise a robotic arm and a manipulator for guiding a surgical instrument to perform a surgical operation, the manipulator having a plurality of degrees of freedom, wherein the first feedback information comprises commanded position and posture information for a joint in the robotic arm and/or the manipulator.
In summary, the present invention provides a surgical robot, a control method for the surgical robot, a surgical robot system, and a readable storage medium. The surgical robot includes a manipulation terminal, and the control method for the surgical robot includes: defining a safe zone and a warning boundary outside the safe zone, based on edge information of the surgical object; and based on a distance function between a current position of the manipulation terminal and the warning boundary, as well as on first feedback information from the manipulation terminal and second feedback information produced from an external environmental force, compensating drive information applied by the surgical robot to the manipulation terminal so that, when the manipulation terminal moves out of the safe zone, an impact of the external environmental force on driving of the manipulation terminal is reduced, eliminated or restricted.
With this arrangement, through compensating the drive information applied to the manipulation terminal with the first feedback information and the second feedback information, an actuating joint is reversely compensated for the external environmental force. In this way, such boundary control is achieved that an impact of the external environmental force on a patient is minimized and after the manipulation terminal moves out of the safe zone, an additional torque required to drive a joint in a robotic arm, as well as the external environmental force, must be increased to obtain the same effect, thereby avoiding possible operational errors of the operator.
Those of ordinary skill in the art would appreciate that the accompanying drawings are provided to facilitate a better understanding of the present invention and do not limit the scope thereof in any sense, in which:
Objects, advantages and features of the present invention will become more apparent upon reading the following more detailed description of the present invention, which is set forth by way of particular embodiments with reference to the accompanying drawings. Note that the figures are provided in a very simplified form not necessarily drawn to exact scale and for the only purpose of facilitating easy and clear description of the embodiments. In addition, the structures shown in the figures are usually partial representations of their actual counterparts. In particular, as the figures would have different emphases, they are sometimes drawn to different scales.
As used herein, the singular forms “a”, “an” and “the” include plural referents, and the term “or” is generally employed in the sense of “and/or”, “several” of “at least one”, and “at least two” of “two or more than two”. Additionally, the use of the terms “first”, “second” and “third” herein is intended for illustration only and is not to be construed as denoting or implying relative importance or as implicitly indicating the numerical number of the referenced item. Accordingly, defining an item with “first”, “second” or “third” is an explicit or implicit indication of the presence of one or at least two of the items. As used herein, the term “proximal” generally refer to an end closer to an operator, and the term “distal” generally refer to an end closer to a subject being operated on. The terms “one end” and “the other end”, as well as “proximal end” and “distal end”, are generally used to refer to opposing end portions including the opposing endpoints, rather than only to the endpoints, unless the context clearly dictates otherwise. Those of ordinary skill in the art can understand the specific meanings of the above-mentioned terms herein, depending on their context.
Essentially, the present invention seeks to provide a surgical robot, a control method, a system, and a readable storage medium, which overcome the problem of difficult, inaccurate conventional boundary control for surgical robot, which tends to lead to operational errors. A detailed description is set forth below with reference to the accompanying drawings.
As shown in
Specially, the navigation device includes navigation markers and a tracker 6. The navigation markers include a base fiducial 15 and a guide fiducial 3. The base fiducial 15 is kept stationary. For example, the base fiducial 15 may be fixed to the surgical cart 1 in order to provide a base coordinate system (or base fiducial coordinate system). The guide fiducial 3 is mounted on the osteotomy guide 4 to enable positional tracking of the osteotomy guide 4. The osteotomy guide 4 is mounted at an end of the robotic arm 2 so that the robotic arm 2 supports the osteotomy guide 4 and can adjust the position and orientation of the osteotomy guide 4 in space.
In practice, the tracker 6 is used to capture a signal reflected from the guide fiducial 3 (which is preferred to be a reflection of an optical signal from the tracker 6) and record a position and posture of the guide fiducial 3 (i.e., its position and orientation in the base coordinate system). A computer program stored in a memory of the control device then control, based on the current and desired positions and postures of the guide fiducial 3, movement of the robotic arm 2. As a result, the robotic arm 2 drives the osteotomy guide 4 and the guide fiducial 3 to move until the guide fiducial 3 reaches the desired position and posture, which are mapped to a desired position and posture of the osteotomy guide 4.
Thus, in applications of the surgical robot, the osteotomy guide 4 can be automatically positioned. Moreover, during surgery, the guide fiducial 3 tracks and feeds back in real time the position and posture of the osteotomy guide 4, based on which, the robotic arm 2 is controlled to move to make positional and postural adjustments to the osteotomy guide 4 and hence to a surgical instrument mounted on the osteotomy guide 4 (e.g., a swing saw or an electric drill). In this way, in addition to high positioning accuracy of the osteotomy guide 4 being achievable, the osteotomy guide 4 is supported on the robotic arm 2 rather than fixed on a patient's body, thereby avoiding causing secondary damage thereto.
Generally, the surgical robot further includes the surgical cart 1 and a navigation cart 9. The control device and part of the navigation device are mounted on the navigation cart 9. For example, the processor may be deployed inside the navigation cart 9, while the keyboard 10 may be arranged outside the navigation cart 9 to facilitate manipulation. Additionally, the primary monitor 8, the secondary monitor 7 and the tracker 6 may be all mounted on a mast erected upright on a surface of the navigation cart 9, with the robotic arm 2 being mounted on the surgical cart 1. The use of the surgical cart 1 and the navigation cart 9 enables easy operation throughout a surgical procedure.
The use of the surgical robot in this embodiment for knee replacement surgery generally involves the steps as follows.
Traditional surgery systems and navigated surgery systems without the participation of a robotic arm in positioning require manual adjustment and positioning of an osteotomy guide, which is, however, inaccurate and inefficient. In contrast, by positioning the osteotomy guide 4 with the robotic arm 2, the operator needs not to fix the osteotomy guide on a bone with additional bone screws, reducing trauma to the patient and surgical time. As noted above, the guide fiducial 3 may be mounted on the osteotomy guide 4, but in other embodiments, the guide fiducial 3 may also be mounted on a terminal joint of the robotic arm 2.
Robot-assisted surgery can be achieved based on the above-discussed surgical robot, which can facilitate an osteotomy procedure by helping an operator identify a target site in need of osteotomy, or identify an osteotomy tool. However, during an osteotomy procedure, for example, once immobilization of the robotic arm 2 is achieved, it is difficult to additionally limit the positions and posture of the osteotomy guide 4 any longer to prevent them from being influenced by an external environmental force. Therefore, it is hard to effectively limit movement of the osteotomy guide 4 within a defined range, and operational errors that might cause unnecessary damage to the patient may occur.
On the basis of this, embodiments of the present invention provide a control method for a surgical robot incorporating a manipulation terminal. It would be appreciated that the manipulation terminal includes at least one of the robotic arm 2 and a manipulator (for guiding a surgical instrument to perform a surgical procedure, such as the osteotomy guide 4), or a combination of both. The method is used to control movement of the manipulation terminal. In other application scenarios, the manipulator is not limited to the osteotomy guide 4, and can be alternatively implemented as other devices capable of limiting the range of movement of the manipulation terminal of the surgical robot. The surgical robot is controlled by the method.
Reference is now made to
In Embodiment 1, the osteotomy guide 4 is implemented as a manipulation terminal, as an example. In practice, the osteotomy guide and/or joints of a robotic arm may also be controlled.
Further, referring to
robot
tool
T=
version
robot
A
−1*versiontoolB
Thus, it would be appreciated that the tracker 6 is able to track the position and posture depending simply on movement of the osteotomy guide 4. As the osteotomy tool 5 is mounted on the osteotomy guide 4, the position and posture of the osteotomy guide 4 just reflect those of the osteotomy tool 5.
A control method for the surgical robot includes the steps as follows.
In an exemplary implementation, the surgical object may be a bone, for example. In step S1, a safe zone and a warning boundary are defined. For example, in some implementations, edge information of the bone may be obtained by an image acquisition device (e.g., a scanning device such as a CT scanner), and the safe zone and the warning boundary may be defined based on the edge information of the bone. Specifically, the image acquisition device may capture an environmental boundary of the bone. An operator (e.g., a surgeon) may formulate a preoperative plan based on his/her own experience, and define the warning boundary and the safe zone based on the environmental boundary (in such a manner that the safe zone is encompassed by the environmental boundary, which is in turn encompassed by the warning boundary, wherein the innermost safe zone is area ensuring safe surgical operation).
In step S2, the first feedback information contains commanded position and posture information for joints of the robotic arm 2 and/or the osteotomy guide 4, and the second feedback information contains torque information on the osteotomy guide 4 calculated from the external environmental force acting on the joints of the robotic arm 2 and/or the osteotomy guide 4.
In this embodiment, based on a distance function between the current position of the osteotomy guide 4 (which can be obtained by tracking the position and posture of the osteotomy guide 4 by the tracker 6) and the warning boundary, as well as on position and posture information of the joints of the robotic arm 2 and/or the osteotomy guide 4 and the torque information on the osteotomy guide 4 derived from the external environmental force, a torque compensation control mode is employed to compensate drive information applied by the control device to the osteotomy guide 4, thereby minimizing or eliminating the influence of the external environmental force on the bone. Optionally, examples of the warning boundary may include a warning line, a warning surface and the like. Those skilled in the art may establish the distance function between the current position of the osteotomy guide 4 and the warning boundary. In particular implementations, the distance function may be established by causing the osteotomy guide 4 to move toward the safe zone and stopping it when it reaches the safe zone. As noted above, the osteotomy guide 4 has three joints that enable three degrees of freedom. That is, three degrees of freedom are further provided, in addition to those of the joints in the robotic arm 2. For example, if the robotic arm 2 has 6 degrees of freedom, then the robotic arm 2 and the osteotomy guide 4 will have a total of 9 degrees of freedom. This can result in a significant increase in surgical flexibility.
Optionally, the external environmental force may include resistance from the surgical object (e.g., a bone) to the manipulation terminal (e.g., the osteotomy guide 4) and traction exerted by the operator on the osteotomy guide 4. Specifically, the traction exerted by the operator on the osteotomy guide 4 may be a pushing force, a pulling force or the like applied by his/her hand.
The external environmental force may be measured, for example, by the force sensor 304 and output in the form of an equivalent torque F. Examples of the force sensor 304 may include, but are not limited to, six-dimensional force sensor, joint torque sensor and the like, and the force sensor 304 may be arranged on the osteotomy guide 4. The force sensor 304 can measure traction exerted by the operator on the osteotomy guide 4 and resistance from the bone to the osteotomy guide 4 transmitted through the osteotomy tool 5. Of course, the external environmental force may also be derived as the equivalent torque F from electrical current through the joint driving motor for the osteotomy guide 4.
Referring to
In this embodiment, there is also provided a readable storage medium storing a program thereon, which, when executed, implements the control method as defined above. The readable storage medium may be integrated in the surgical robot, for example, in the control device. Alternatively, it may be attached as a separate component.
In this embodiment, there is further provided a surgical robot system comprising a control device, a navigation device and a manipulation terminal. The navigation device is configured to track the current position and posture of the manipulation terminal and feed information about the position and posture back to the control device. The control device is configured to control the manipulation terminal according to the method as defined above. Preferably, in the surgical robot system, the manipulation terminal includes a robotic arm and a manipulator for guiding a surgical instrument to perform a surgical operation. The manipulator has multiple degrees of freedom, and the first feedback information includes commanded position and posture information of joints in the robotic arm and/or the manipulator.
In summary, through compensating the drive information applied to the manipulation terminal with the first feedback information and the second feedback information, the actuating joints are reversely compensated for the external environmental force. In this way, such boundary control is achieved that an impact of the external environmental force on a patient is minimized and after the manipulation terminal moves out of the safe zone, the external environmental force must be increased to obtain the same effect, avoiding possible operational errors of the operator.
Reference is now made to
Embodiment 2 of the present invention provides a surgical robot, a control method, a system, and a readable storage medium, which are substantially the same as the surgical robot, the control method, the system, and the readable storage medium provided in Embodiment 1, respectively. Below, only different features will be described, and description of those common to the two embodiments will be omitted.
In the control method provided in Embodiment 2, essentially, an impedance control mode is employed to compensate for traction applied by an operator. Specifically, in step S2, the first feedback information includes commanded position and posture information for the joints in the manipulation terminal, and the second feedback information includes an impedance control model of the external environmental force over the joints of the manipulation terminal.
Similarly, in Embodiment 2, the surgical object is implemented as a bone and the osteotomy guide 4 as the manipulation terminal, as an example.
Referring to
Preferably,
An input to the impedance control model is derived using a method including the steps as follows:
In the foregoing embodiments, the manipulation terminal is implemented as the osteotomy guide 4. Since the osteotomy guide 4 has only three degrees of freedom, this is conducive to the establishment of simpler kinematic and dynamic models and hence to the implementation of inverse kinematics 301, forward kinematics 310 and dynamic calculations 305. However, in some other embodiments, the manipulation terminal may be alternatively implemented as the robotic arm 2, or as a combination of the robotic arm 2 and the osteotomy guide 4. It would be appreciated that in case of more than three degrees of freedom, in addition to torques, corresponding forces must also be taken into account in the above methods of control. It would be also appreciated that, in some other embodiments, the methods of control are not limited to knee replacement surgery applications.
The embodiments disclosed herein are described in a progressive manner, with the description of each embodiment focusing on its differences from others. Reference can be made between the embodiments for their identical or similar features. Additionally, features of different embodiments may be combined with one another, without limiting the scope of the present invention.
In summary, the present invention provides a surgical robot, a control method for the surgical robot, a surgical robot system, and a readable storage medium. The surgical robot includes a manipulation terminal, and the control method for the surgical robot includes: defining a safe zone and a warning boundary encircling the safe zone, based on edge information of the surgical object; and based on a distance function between a current position and posture of the manipulation terminal and the warning boundary, as well as on first feedback information from the manipulation terminal and second feedback information produced from an external environmental force, compensating drive information applied by the surgical robot to the manipulation terminal so that, when the manipulation terminal moves out of the safe zone, an impact of the external environmental force on driving of the manipulation terminal is reduced, eliminated or restricted. With this arrangement, through compensating the drive information applied to the manipulation terminal with the first feedback information and the second feedback information, an actuating joint is reversely compensated for the external environmental force. In this way, such boundary control is achieved that an impact of the external environmental force on a patient is minimized and after the manipulation terminal moves out of the safe zone, an additional torque required to drive a joint in a robotic arm, as well as the external environmental force, must be increased to obtain the same effect, thereby avoiding possible operational errors of the operator.
The description presented above is merely that of a few preferred embodiments of the present invention and does not limit the scope thereof in any sense. Any and all changes and modifications made by those of ordinary skill in the art based on the above teachings fall within the scope as defined in the appended claims.
Number | Date | Country | Kind |
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202011223748.X | Nov 2020 | CN | national |
Filing Document | Filing Date | Country | Kind |
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PCT/CN2021/128828 | 11/4/2021 | WO |