Patent Description:
Minimal invasive surgery is accepted by more and more patients because of its advantages of small wounds and rapid recovery, and more and more surgical modes are applied in minimal invasive surgeries gradually progressed from traditional open surgery. At the same time, the continuous advancement of surgical methods has also greatly promoted the development and progress of corresponding surgical devices. Early handheld surgical devices have been continuously replaced by mechanized and intelligent surgical devices. As the most advanced surgical device in the contemporary era, surgical robot systems are constantly impacting people's medical ideas, and various minimal invasive surgical robot systems with different functions are constantly emerging.

In minimal invasive surgery, laparoscopic surgery has been basically popular because of its early realization. Among existing laparoscopic surgical robot systems, the DaVinci system has been recognized as one of the most outstanding ones in the world, and the use of the DaVinci system almost covers Europe and America, which reflects that it has absolute advantages. The basic control concept of the DaVinci surgical robot system is the control mode of the master-slave remote control operation. The doctor controls the surgical instruments of the bedside robot through the master manipulator of the master console. In general, the bedside robot has multiple robotic arms capable of holding surgical instruments and an endoscope. However, the surgical instruments of the surgical robot system are different from traditional surgical instruments, and they have features of more automatic and intelligent.

The surgical instruments of the surgical robot system generally contain four degrees of freedom: rotation, swing, pitching, and opening/closing, so that they can best simulate the acting of human hands. When the doctor operates the robot, the operations of the surgical instrument like operations performed by the doctor's own hands. Moreover, surgical instruments are more flexible than human hands and can perform operations that human hands cannot do. However, surgical instruments in such systems as the inventor knows, are still suffering from a number of deficiencies, the major ones of which are as follows:
<CIT>
discloses a modular force sensor which comprises a tube portion including a plurality of strain gauges, a proximal tube portion for operably coupling to a shaft of a surgical instrument and a distal tube portion for proximally coupling to a wrist joint coupled to an end portion. <CIT> discloses a robot having a force sensor attached between a wrist portion and a hand portion. <CIT> discloses a robotic hand controller for enabling a user to perform an activity.

It is an objective of some embodiments of the present application to overcome at least one of the problems of conventional mechanisms for measuring a contact force acting on a terminal of a surgical instrument, such as structural complexity, computational complexity and low accuracy, by providing a surgical robot system and a surgical instrument thereof.

According to an aspect of the present application, there is provided a surgical instrument, comprising a mechanical structural unit and a pressure sensor unit, wherein,.

Optionally, the first connector is a hollow support shaft, the second connector is a hollow base, the base is formed from an axial extension of a proximal end of the end effector, and the base is configured to sleeve with the support shaft.

Optionally, the first connector is an outer layer structure, the second connector is an inner layer structure, the outer layer structure is radially connected with the inner layer structure to form a groove in which the sensitive element is arranged.

Optionally, the groove has a U-shaped axial section.

Optionally, a size of an outer surface of the first connector is smaller than a size of an inner surface of the second connector; and
the size of the inner surface of the second connector is smaller than a sum of the size of the outer surface of the first connector and a radial dimension of the sensitive element.

Optionally, a size of an inner surface of the second connector is greater than a sum of a size of an outer surface of the first connector and a radial dimension of the sensitive element, and a filler is arranged between the first connector and the second connector to increase an elasticity between the first connector and the second connector.

Optionally, a size of an inner surface of the first connector is larger than a size of an outer surface of the second connector, and
the size of the inner surface of the first connector is smaller than a sum of the size of the outer surface of the second connector and a radial dimension of the sensitive element.

Optionally, a size of an inner surface of the first connector is larger than a sum of a size of an outer surface of the second connector and a radial dimension of the sensitive element, and a filler is arranged between the first connector and the second connector to increase an elasticity between the first connector and the second connector.

Optionally, the filler is made from rubber or silicone.

Optionally, the pressure sensor unit comprises one sensitive element, or comprises a plurality of sensitive elements, and the plurality of sensitive elements are distributed along a circumferential direction and/or an axial direction of the surgical instrument.

Optionally, the plurality of sensitive elements are distributed in a plurality of rows in the axial direction of the surgical instrument, and the sensitive elements in each of the rows are evenly distributed in the circumferential direction of the surgical instrument.

Optionally, each of the rows of sensitive elements is arranged staggeredly with an adjacent one of the rows of sensitive elements.

According to another aspect of the present application, there is provided a surgical robot system, comprising a slave device comprising:.

Optionally, the surgical robot system further comprises a master device and a control unit, the master device comprising a force indicator;
wherein the control unit is communicatively connected to the master device and to the slave device, and the control unit is configured to obtain information about a Cartesian force received by the end effector from the sensitive element of the surgical instrument and transmits the information to the force indicator.

Optionally, the force indicator is a master manipulator provided with a motor, and the control unit is configured to issue a torque command to the motor of the master manipulator to enable an operator to feel a force acting on the terminal of the surgical instrument.

Optionally, the master manipulator further comprises a vibrating motor; when the force acting on the terminal of the surgical instrument exceeds a preset threshold, the control unit issues a vibration command to the vibrating motor of the master manipulator, notifying the operator about the excessive force acting on the terminal of the surgical instrument.

The surgical instrument according to the present application has a first connector and a second connector that are radially distributed, and a sensitive element of a pressure sensor unit is provided between the first connector and the second connector, and the sensitive element is configured to sense the force applied by the second connector onto the first connector, and according to the force information, the Cartesian force acting on the end effector of the surgical instrument can be determined.

In some embodiments, the pressure sensor unit is a strain pressure sensor, a piezoresistive pressure sensor, or a piezoelectrical pressure sensor. The sensitive element is disposed between the first connector and the second connector to receive the force at the connecting area. When the end effector of the surgical instrument is subjected to an external force (i.e., a Cartesian force), the force exerted by the second connector on the sensitive element and on the first connector deforms the sensitive element and generates deformation information. Further, through determining the pressure between the first connector and the second connector based on the deformation information, the Cartesian force acting on the end effector of the surgical instrument can be accurately and uniquely measured.

In particular, the distal end of the instrument shaft of the surgical instrument extends axially to form a double-layer and hollow support shaft. Preferably, the support shaft has a groove with a U-shaped axial cross-section. Due to the U-shaped thin wall of the support shaft, the thin-walled feature can further improve the accuracy in determining the force acting on the end effector of the surgical instrument.

Compared with the conventional solutions using a motor output to calculate the force acting on the end effector of the surgical instrument, the surgical instrument of the present application has advantages of both a simpler force transmission path and higher force measurement accuracy. Moreover, the force acting on the terminal of the surgical instrument can be determined in an easier manner without requiring additional components, providing for lower structural complexity of the surgical instrument and facilitating its assembly. Further, since minor changes are required in the surgical instrument, various existing surgical instruments after being modified with minor changes also can be suitably used in the surgical robot system proposed by the present application.

The above and other objectives, features and advantages of the present application will become more apparent from the following detailed description of the proposed surgical robot system and surgical instrument thereof, which is to be read in connection with <FIG>. Note that the figures are much simplified and may not be drawn to scale, and the only purpose of them is to facilitate easy and clear explanation of the disclosed embodiments. As used herein, a "trailing end", "terminal" or "distal end" refers to an end farther way from an operator and closer to a patient, while a "leading end" or "proximal" refers to an end closer to the operator and farther way from the patient. As used in present disclosure, the meaning of "a" "an" and "the" include singular and plural references, unless the context clearly dictates otherwise.

The surgical robot systems according to these embodiments described below are able to measure a radial force and/or an axis force acting on the terminal of the surgical instrument.

<FIG> is a structural schematic of a surgical robot system. The surgical robot system includes a slave device including a surgical cart <NUM>, robotic arms <NUM>, a surgical instrument <NUM>, an endoscope <NUM>. As a base of the whole slave device, the surgical cart <NUM> supports all the other components of the slave device described above. Meanwhile, the surgical cart <NUM> is moveable on the ground to allow the slave device to approach or leave a patient.

The robotic arm <NUM> with multiple degrees of freedom is mounted on the surgical cart <NUM> and configured to drive the surgical instrument <NUM> to pivot about a remote center of motion. When the surgical cart <NUM> moves to the vicinity of the patient, the robotic arm <NUM> may be adjusted so that the surgical instrument <NUM> arrives at a predetermined target surgical site. In other words, the remote center of motion is located around the surgical site by adjusting both the surgical cart <NUM> and the robotic arm <NUM>. The surgical instrument <NUM> is detachably mounted at a terminal of the robotic arm <NUM> through a fixed connection or a movable connection. As an output of the slave device, the surgical instrument <NUM> will eventually enter into the patient's body at the surgical site so as to treat a target lesion.

The endoscope <NUM> is mounted at a terminal of one of the robotic arms <NUM> different from that on which the surgical instrument <NUM> is coupled and is configured to collect image information about the surgical environment. The image information may include, but is not limited to, the information about tissue around the lesion and that about a posture and position of the surgical instrument <NUM>. When mounted on the robotic arm <NUM>, the endoscope <NUM> may be communicatively connected to the master device as detailed below so as to enable real-time display of the information about the surgical environment collected thereby. The endoscope <NUM> may be three-dimensional or not, which is not limited by the present application.

With continued reference to <FIG>, the surgical robot system further includes a master device which includes an imaging system <NUM>, a master manipulator <NUM>, an armrest <NUM> and a console base <NUM>. During a surgical operation, with the information from the endoscope <NUM> being displayed by the imaging system <NUM>, a doctor can observe motion of the surgical instrument <NUM> through the imaging system <NUM>, and accordingly control the subsequent movement of the surgical instrument <NUM> by manipulating the master manipulator <NUM>. The doctor may sit at a surgical console and, with the aid of the imaging system <NUM>, observe the position and motion of the terminal of the surgical instrument in vivo. Based on the observations, the doctor can control a multi-dimensional movement (such as rotation, swing, pitching, and opening/closing) of the terminal by manipulating the master manipulator <NUM>, thus allowing for a minimally invasive operation. The armrest <NUM> can support the doctor's arm so that the doctor can maintain a higher comfort when the surgical operation lasts for a long time. In addition, the armrest <NUM> can be raised and lowered to meet various needs of different doctors. The console base <NUM> serving as the basic structure of the master device can move freely on the ground, and it supports all the other structures of the master device described above.

The specific surgical operation of the surgical robot system is described as follows.

Firstly, the doctor control the surgical cart <NUM> and the console base <NUM> to push the slave device to the vicinity of the operating table where the patient lies, so that the slave device is in a better operation position, and to push the master device to a relatively better manipulation position, which is convenient for doctors to manipulate.

Then, through adjusting the mechanical arm <NUM>, the surgical instrument <NUM> and the endoscope <NUM> are driven to the vicinity of the surgical incision.

After that, the surgical instrument <NUM> and the endoscope <NUM> are inserted into the patient's body through the incision on the patient;.

Finally, the doctor observes the position and movement state of the end effector of the surgical instrument <NUM> in the patient's body through the stereoscopic imaging system <NUM>, and adjusts the position and movement state of the end effector through the master manipulator <NUM>, and then performs a minimal invasive surgery.

Apparently, the control made from the master manipulator <NUM> to the surgical instrument <NUM> is basic to the master/slave control in the surgical robot system. In order to better simulate the actual circumstances of a surgical operation, i.e., simulate the force acting on the surgical instrument <NUM> during the operation, it is desired that the surgical instrument <NUM> is able to feed back any force acting on it to the master manipulator <NUM>, i.e., providing the surgical instrument <NUM> with force feedback capabilities, so that the doctor can adaptively adjust surgical operation. Therefore, the present application provides a surgical instrument equipped with a sensing device and a corresponding surgical robot system.

Specifically, the surgical instrument <NUM> further includes a sensing device <NUM> for sensing the force acting on the terminal of the surgical instrument <NUM>. The surgical robot system further includes a control unit <NUM> for receiving and transmitting the information about the force acting on the surgical instrument <NUM> acquired by the sensing device <NUM>. The control unit <NUM> communicatively connected to both the master and slave devices, for example, by wired or wireless connections. The control unit <NUM> is responsible for, based on a control strategy, processing data from the sensing device <NUM> and calculating various data required in the controlling. The control unit <NUM> is configured to transmit information about the force acting on the terminal of the surgical instrument <NUM> to a force indicator of the master device, so that the force acting on the terminal of the surgical instrument <NUM> can be perceived by the doctor.

The force indicator may be the imaging system <NUM>, which can display the magnitude and direction of the force acting on the terminal of the surgical instrument <NUM>. Alternatively, the force indicator may be the master manipulator <NUM> equipped with a motor. While the doctor manipulates the system, the control unit <NUM> may control the motor of the master manipulator <NUM> based on the information about the force acting on the terminal of the surgical instrument <NUM> and may exert a force acting onto the doctor. Apparently, the control made from the master manipulator <NUM> to the surgical instrument <NUM> is basic to the master/slave control in the surgical robot system. In order to better simulate the actual circumstances of a surgical operation, i.e., simulate the force acting on the surgical instrument <NUM> during the operation, it is desired that the surgical instrument <NUM> is able to feed back any force acting on it to the master manipulator <NUM>, and provided with force feedback capabilities. After a force acting on the terminal of the surgical instrument <NUM> is determined based on the force data sensed by the sensing device <NUM>, the control unit <NUM> can issue a torque command to the motor of the master manipulator <NUM>, to enable the operator to perceive the force acting on the terminal of the surgical instrument <NUM>. More preferably, the master manipulator <NUM> may be provided with a vibrating motor. In this case, when the force acting on the terminal of the surgical instrument <NUM>, which is determined from the force data sensed by the sensing device <NUM>, exceeds a preset threshold, the control unit <NUM> can issue a vibration command to the vibrating motor of the master manipulator <NUM>, notifying the operator about the excessive force acting on the terminal of the surgical instrument <NUM>.

In the present application, the surgical instrument includes a mechanical structural unit and a pressure sensor unit. The mechanical structural unit includes an instrument shaft and an end effector. The instrument shaft includes a body and a connecting portion extending from a distal end of the body. The instrument shaft is connected to the end effector through the connection portion, and the pressure sensor unit serves as the sensing device <NUM> of the present application, and the sensitive element thereof senses the force thereon applied by the connection portion (that is, the Cartesian force received by the end effector). Next, the implementation of the surgical instrument will be described in further detail.

First, referring to <FIG> and <FIG>, <FIG> schematically shows a mechanical structural unit of a surgical instrument, and <FIG> shows a partially enlarged view of the mechanical structural unit of the surgical instrument shown in <FIG>. As shown, the mechanical structural unit of the surgical instrument <NUM> includes a power module <NUM>, a mounting base <NUM>, an instrument shaft <NUM>, a force transmission mechanism <NUM> and an end effector <NUM>.

The power module <NUM> is disposed at a proximal end of the instrument shaft <NUM>, while the end effector <NUM> is disposed at a distal end of the instrument shaft <NUM>. The power module <NUM> is configured to provide a driving force, which is transferred by the force transmission mechanism to the end effector <NUM>, thus enabling the end effector <NUM> to perform a multi-dimensional rotational motion and/or opening/closing action, etc..

The power module <NUM> is detachably connected to an external motor, and configured to receive force from the external motor. Particularly, the power module <NUM> is connected to the motor through a reducer. The force output by the motor is increased by the reducer and then transmitted to end effector <NUM> through the power module <NUM> and the force transmission mechanism <NUM>. For example, the force transmission mechanism <NUM> is a wire transmission, which includes a steel wire and a guide wheel. The steel wire is used to transmit force, and the guide wheel is used to adjust the extension direction of the steel wire. Specifically, the force transmission mechanism <NUM> goes through the instrument shaft <NUM> and is connected to the power module <NUM> and the end effector <NUM>. The end effector <NUM> is configured to perform specific operations, such as scissoring, knotting and grabbing, to the lesion site in the patient's body. The present application is not limited to any particular type of the end effector <NUM> as it can be scissors, pliers, a probe or the like.

The mounting base <NUM> is detachably connected to the terminal of the robotic arm <NUM>. Preferably, the power module <NUM> is accommodated in the mounting base <NUM>. The proximal end of the instrument shaft <NUM> is connected to the mounting base <NUM>, and the distal end is connected to the end effector <NUM>. The instrument shaft <NUM> has a sufficient length so that the end effector <NUM> can treat a patient's site during the operation.

The instrument shaft <NUM> includes a body and a connecting portion <NUM> extending from the distal end of the body (see <FIG>). The connecting portion <NUM> includes a first connecting member and a second connecting member that are radially distributed, the first connecting member is fixedly connected to the body of the instrument shaft, and the second connecting member is fixedly connected to the end effector. Furthermore, the sensitive element of the pressure sensor unit is disposed between the first connection member and the second connection member, that is, located on the connection portion <NUM> of the instrument shaft <NUM>, for sensing the force exerted thereon by the connection portion <NUM>, thereby determining the force acting on the connection part <NUM> and even the overall stress of the end effector <NUM> (that is, the reactive force from the human tissue to the end effector <NUM>). The connecting portion <NUM> can be formed separately from the body of the instrument shaft <NUM>, that is, processed separately and then assembled together to become a whole. In addition, the sensitive element may be selected from strain gauges such as piezoelectric strain gauges, piezoresistive strain gauges, strain gauges, etc., to sense the force acting on the connecting portion <NUM>. In some embodiments, the pressure sensor unit includes a circuit containing a sensitive element. When the sensitive element deforms due to force and the resistance changes, the current or voltage of the circuit also changes. Based on relationship between the calibrated current/voltage and pressure, the pressure sensor unit senses the pressure acting on the sensitive element.

For example, in the embodiment shown in <FIG>, the first connector and the second connector are designed as two separate members. Specifically, the second connector is a terminal base <NUM> connected to the proximal end of the end effector <NUM>, and the terminal base <NUM> has a hollow structure to facilitate the passage of the aforementioned force transmission mechanism <NUM>. The first connector is a support shaft <NUM> fixedly connected to the body of the instrument shaft <NUM>. Similarly, the support shaft <NUM> also has a hollow structure to facilitate the passage of the force transmission mechanism <NUM>. The diameter and material of the support shaft <NUM> may be the same as other parts of the instrument shaft <NUM>, or may be different. Moreover, one or more sensitive elements <NUM> are attached to the outer surface (preferably an outer circular surface) of the support shaft <NUM>. Preferably, a plurality of the sensitive elements <NUM> are evenly distributed along the circumferential direction of the support shaft <NUM>. More preferably, the support shaft <NUM> is provided with a plurality of rows of sensitive elements <NUM> distributed uniformly in the axial direction, and each row of sensitive elements <NUM> and the adjacent row of sensitive elements <NUM> are staggered. In addition, the inner diameter of the terminal base <NUM> is larger than the outer diameter of the support shaft <NUM>, and slightly smaller than the sum of the outer diameter of the support shaft <NUM> and the radial dimension of the sensitive element <NUM> to obtain an interference fit, so that the support shaft <NUM> can be inserted into the terminal base <NUM> and fixed with it. Here, the radial dimension of the sensitive element <NUM> is the thickness of the sensitive element <NUM> along the cross-sectional direction of the terminal base <NUM> or the support shaft <NUM>. Before the use of the sensitive element <NUM>, the measurement error of sensitive components due to interference fit can be removed through adjustment to the measurement reference. In other embodiments, the inner diameter of the terminal base <NUM> is slightly larger than the sum of the outer diameter of the support shaft <NUM> and the radial dimension of the sensitive element <NUM>, that is, a clearance fit is formed between the two. If the base terminal <NUM> in clearance fit with the support shaft <NUM>, a filler, such as an elastic rubber, silicone, is preferably provided in the clearance between the terminal base <NUM> and the support shaft <NUM>, for the better elasticity of the connecting portion <NUM>. Further, the base terminal <NUM> and the support shaft <NUM> are preferably coaxially arranged and in a clearance fit manner.

In the connection portion <NUM> formed by the terminal base <NUM> and the support shaft <NUM> being sleeved therein, the support shaft <NUM> is fixedly connected to the body of the instrument shaft <NUM>, the terminal base <NUM> is fixedly connected to the end effector <NUM>, and the sensitive element <NUM> is disposed between the support shaft <NUM> and the terminal base <NUM>. When the end effector <NUM> of the surgical instrument <NUM> is subjected to Cartesian force and transmits the Cartesian force to the terminal base <NUM>, the terminal base <NUM> exerts the Cartesian force on the sensitive element <NUM>. This force is immediately sensed by the sensitive element <NUM>. Therefore, through measuring the force acting on the terminal base <NUM> and the support shaft <NUM>, the Cartesian force received by the surgical instrument terminal <NUM> can be accurately and uniquely measured, and moreover, measurement errors caused by changes in the structure of the surgical instrument terminal can be avoided.

Specifically, during an actual surgery, when the end effector <NUM> of the surgical instrument <NUM> is subjected to Cartesian force exerted by human tissue, the end effector <NUM> transmits the Cartesian force to the terminal base <NUM>, and the terminal base <NUM> then exerts the Cartesian force onto the sensitive element <NUM> which is attached to the outer surface of the support shaft <NUM>. Therefore, based on the force data obtained from sensing of the sensitive element <NUM>, the Cartesian force received by the end effector <NUM> of the surgical instrument <NUM> can be perceived.

However, the sensitive element <NUM> is not limited to being attached to the outer surface of the support shaft <NUM>, but can also be attached to the inner surface (preferably an inner circular surface) of the terminal base <NUM>. In this case, the inner diameter (i.e., the inner diameter of the terminal base <NUM> minus the radial dimension of the sensitive element <NUM>) of the terminal base <NUM> to which the sensitive element <NUM> has been attached may be slightly smaller than the outer diameter of the support shaft <NUM> to obtain an interference fit.

Different from the foregoing embodiment, the first connector of the connection portion <NUM> is sleeved over the second connector, see <FIG> for details. In the embodiment shown in <FIG>, the second connector is a terminal base <NUM> connected to the proximal end of the end effector <NUM>, and the terminal base <NUM> has a hollow structure to facilitate the passage of the force transmission mechanism <NUM>. The first connector is a support shaft <NUM> fixedly connected to the body of the instrument shaft <NUM>. Similarly, the support shaft <NUM> also has a hollow structure so that the force transmission mechanism <NUM> can pass through. The diameter and material of the support shaft <NUM> may be the same as other parts of the instrument shaft <NUM>, or may be different. One or more sensitive elements <NUM> are attached to the inner surface (preferably the inner circular surface) of the support shaft <NUM>. The difference from the above embodiment is that the outer diameter of the terminal base <NUM> is smaller than the inner diameter of the support shaft <NUM>, and slightly larger than the difference between the inner diameter of the support shaft <NUM> and the radial dimension of the sensitive element <NUM>, that is, the terminal base <NUM> can be Inserted into the support shaft <NUM> in an interference fit manner. Similarly, the outer diameter of the terminal base <NUM> may be slightly smaller than the difference between the inner diameter of the support shaft <NUM> and the radial dimension of the sensitive element <NUM>, that is, a clearance fit is obtained between the terminal base <NUM> and the support shaft <NUM>, and a filler, such as an elastic rubber, silicone, or the like, are arranged in the clearance between the terminal base <NUM> and the support shafts <NUM>. Preferably, the terminal base <NUM> is coaxially arranged and in a clearance fit manner with the support shaft <NUM>.

In addition to the inner surface of the support shaft <NUM>, the sensitive element <NUM> can also be attached to the outer surface (preferably the outer circular surface) of the terminal base <NUM>. In this case, the outer diameter (i.e., the sum of the outer diameter of the terminal base <NUM> and the radial dimension of the sensitive element <NUM>) of the terminal base <NUM> to which the sensitive element <NUM> has been attached is slightly larger than the inner diameter of the support shaft <NUM> to obtain an interference fit, or the outer diameter of the terminal base <NUM> and the radial dimension of the sensitive element <NUM> is slightly smaller than the inner diameter of the support shaft <NUM> to obtain a clearance fit, and a filler is used to fill the clearance between the two.

Either of the above terminal bases <NUM>, <NUM> can be formed by the axial extension of the proximal end of the end effector <NUM>.

In addition, the first connector and the second connector may be designed in one piece to simplify the structure of the surgical instrument and optimize the size of the surgical instrument. Similar to the above embodiment, in another preferred solution shown in <FIG>, the first connector is implemented as the outer layer structure <NUM> connected to the distal end of the body of the instrument shaft <NUM>. The outer layer structure <NUM> has a hollow structure to facilitate the passage of the force transmission mechanism <NUM>. The second connector is implemented as the inner layer structure <NUM> connected to the proximal end of the end effector <NUM>, and the inner layer structure <NUM> is hollowed to facilitate the passage of the aforementioned force transmission mechanism <NUM>. The connecting portion <NUM> is fixedly connected to the end effector <NUM>, and preferably the inner layer structure <NUM> is fixedly connected to the end effector <NUM>. In particular, the outer layer structure <NUM> is disposed at the periphery of the inner layer structure <NUM>, and is radially connected to the inner layer structure <NUM>, together forming a shaft arm of the connecting portion <NUM> of the instrument shaft. Thus, a groove <NUM> is formed between the inner layer structure <NUM> and the outer layer structure <NUM>. Preferably, the groove <NUM> is U-shaped. Preferably, a reinforcing plate is provided in the groove <NUM> to enhance its structural strength. Furthermore, one or more sensitive elements <NUM> are disposed in the groove <NUM>, for example, attached to the inner surface of the outer layer structure <NUM> of the connecting portion <NUM>, or attached to the outer surface of the inner layer structure <NUM> of the connecting portion <NUM>. Preferably, a filler is provided in the groove <NUM>, such as elastic rubber, silicone, etc., so as to increase the elasticity of the connecting portion <NUM>.

It should be understood that when the end effector <NUM> is subjected to the force exerted by the human tissue, the inner and outer layer structures forming the groove <NUM> may be deformed to some extent due to the hollow structure of the shaft arm of the connecting portion <NUM>, thereby squeezing sensitive element <NUM>, and accordingly the sensitive element <NUM> is deformed. According to the deformation, the pressure sensor unit can determine the force received by the sensitive element <NUM>, and then can sense the force (including the magnitude and direction thereof) acting on the end effector <NUM>, and finally determine the force acting on the terminal of the surgical instrument. Optionally, a plurality of the sensitive elements <NUM> are uniformly distributed circumferentially in the groove <NUM>, and more preferably, the groove <NUM> is provided with a plurality of rows of sensitive elements <NUM> distributed circumferentially and uniformly along the axial direction, which improves the accuracy of detection.

While a detail description about the structures of the surgical instrument has been given above, it is a matter of course that the present application includes, but is not limited to, the above-described configurations, and any modification made thereto are intended to also fall within the scope of the application. Those skilled in the art can arrive at other embodiments in light of the teachings of the foregoing embodiments.

In addition, the present application also provides a surgical robot system. The surgical robot system includes a slave device. The slave device includes a robot arm and the surgical instrument mentioned above. The surgical instrument is detachably connected to the terminal of the robot arm, so that the surgical instrument can be driven to move around a remote center of motion. Furthermore, the surgical robot system further includes a master device and a control unit. The master device includes a force indicator. The control unit is communicatively connected with the master device and the slave device. The control unit is configured to determine the information of the Cartesian force received by the end effector from the sensitive element of the surgical instrument and transmit the information to the force indicator. Furthermore, the control unit <NUM> may employ an existing PLC controller, microcomputer, microprocessor or the like, and one skilled in the art will understand how to implement such a selection based on the disclosure herein in combination with the common general knowledge in the art.

The surgical instrument of the present application according to the present application has a first connector and a second connector that are radially distributed, and a sensitive element is disposed between the first connector and the second connector, and the sensitive element can sense the force acting on the terminal of the instrument shaft of the surgical instrument, and then the Cartesian force received by the end effector of the surgical instrument is determined. Furthermore, in some embodiments, the pressure sensor unit is a strain pressure sensor, a piezoresistive pressure sensor or a piezoelectric pressure sensor, and the sensitive element is arranged between the first connector and the second connector to sense the force acting on the connecting portion. The terminal of the surgical instrument is subjected to an external force, so that the first connector and the second connector are subjected to the force accordingly and transmit the force to the sensitive element, and thus the sensitive element is deformed. Such deformation is sensed by the sensitive element immediately, so that the force acting on the connecting portion can be determined. Therefore, the pressure between the first connector and the second connector is determined from the deformation information, and the Cartesian force acting on the terminal of the surgical instrument can be accurately and uniquely measured.

In particular, the distal end of the instrument shaft of the surgical instrument extends axially to form a double-layer hollow support shaft. Preferably, the support shaft has a groove with a U-shaped axial cross-section. Due to the U-shaped thin wall of the support shaft, the accuracy of determining the force acting on the terminal of the surgical instrument can be further improved.

Compared with the conventional solutions using a motor output to calculate the force acting on the terminal of the surgical instrument, the surgical instrument of the present application has advantages of both a simpler force transmission path and higher force measurement accuracy. Moreover, the force acting on the terminal of the surgical instrument can be determined in an easier manner independently of the constructions of the surgical instrument without requiring additional components, providing for lower structural complexity of the surgical instrument and facilitating its assembly. Further, since minor changes are required in the surgical instrument, various existing surgical instruments after being modified with minor changes can be suitably used in the surgical robot system proposed by the present application.

Claim 1:
A surgical instrument (<NUM>), comprising a mechanical structural unit and a pressure sensor unit, wherein,
the mechanical structural unit comprises an instrument shaft (<NUM>) and an end effector (<NUM>); the instrument shaft (<NUM>) comprises a body and a connecting portion (<NUM>) extending from a distal end of the body; the connecting portion (<NUM>) comprises a first connector and a second connector that are coaxially disposed; the first connector is fixedly connected to the body of the instrument shaft (<NUM>), and the second connector is fixedly connected to the end effector (<NUM>);
the pressure sensor unit comprises a sensitive element (<NUM>, <NUM>, <NUM>) disposed between the first connector and the second connector;
characterized in that,
when the end effector (<NUM>) is subjected to Cartesian force, the second connector squeezes the sensitive element (<NUM>, <NUM>, <NUM>) so as to exert a force dependent on the Cartesian force onto the sensitive element (<NUM>, <NUM>, <NUM>), and the sensitive element (<NUM>, <NUM>, <NUM>) is configured to sense the force from the second connector thereby obtaining a force data so that the Cartesian force received by the end effector (<NUM>) is determined based on the force data.