Control system for surgical instruments

Abstract

A control system suitable for nerve traction comprises a force sensor, a conversion element, force / position / velocity controllers, and a transmission mechanism that drives the surgical instrument. The system offers two control modes. In collaborative mode, the force sensor detects the applied force and outputs a signal to a conversion element with a designed dead zone, resulting in a velocity control command for driving the transmission mechanism. The dead zone reduces noise interference and ensures the instrument is automatically maintained at the traction state after being released. In constant-force mode, the system holds the instrument at a default traction force. The force controller calculates a constrained position command based on the difference between the default and measured forces. This command is processed by the position and velocity controllers and then used to drive the instrument, thus limiting displacement of the instrument and avoiding nerve damage. The system enables adjustments to traction force magnitude, duration, and intervals, offering precise, safe, and customizable traction control.

Description

Surgical instrument control systems The present invention relates to a control system for a surgical instrument, in particular to a control system used in spinal decompression surgery to assist an operator in stably operating a nerve hook. Spinal decompression surgery is widely used to treat patients with lumbar degeneration or spinal nerve compression. To create space for surgery, doctors use nerve hooks to isolate the nerves near the surgical site, thereby preventing accidental injury to nearby nerves during surgery. Physicians currently rely entirely on experience to manually manipulate the nerve hook. However, prolonged surgeries can disrupt even experienced surgeons' ability to maintain focus, leading to inability to apply the appropriate force. If the hook pulls on the nerve with excessive force or for an extended period, it can damage nerves near the spine, leading to postoperative pain and limb weakness. The problem to be solved by the present invention is to provide a nerve hook surgical instrument control system suitable for spinal decompression surgery based on the existing technology. In order to solve the above-mentioned problems, the technical solution adopted by the present invention is to provide a control system for a surgical instrument. The control system includes a force sensor, a conversion element, an encoder, a processing circuit, a speed controller, a force controller, a position controller, and a transmission mechanism that drives the surgical instrument. The force sensor is connected between the surgical instrument and the transmission mechanism and is configured to measure the force condition of the surgical instrument to generate a force sensing signal. The conversion element is configured to convert the force sensing signal into a speed command signal, and the conversion element includes a dead zone range. When the force sensing signal is within the dead zone range, the speed corresponding to the speed command signal is zero. The encoder is connected to the transmission mechanism and is configured to measure the rotation angle of the transmission mechanism to generate an encoder measurement signal. The processing circuit is configured to generate a position sensing signal and a speed sensing signal of the transmission mechanism based on the encoder measurement signal. The speed controller is configured to generate a speed error signal based on the error between the speed command signal and the speed sensing signal. The speed error signal is calculated by the speed controller to generate a torque command signal. In addition, the control system of the surgical instrument of the present invention may also include a processing circuit, a force controller, a position controller, and a conversion element. The processing circuit is configured to generate a force command signal set by the user. The force controller is configured to generate a force error signal based on the error between the force command signal and the force sensing signal, and the force error signal is calculated by the force controller to generate a position command signal. The position controller is configured to generate a position error signal based on the error between the position command signal and the position sensing signal, and the position error signal is calculated by the position controller to generate a speed command signal. The speed command signal generated by the conversion element or the position controller is then calculated by the speed controller to generate a torque command signal to drive the transmission mechanism. The present invention has two beneficial effects. The first is a collaborative mode. During a physician's manual nerve hook application, a force sensor detects the physician's applied force and, in conjunction with a speed controller, drives the nerve hook to pull the nerve to a predetermined position at a stable speed. The speed controller's dead zone design prevents erroneous or fluctuating speed command signals due to noise in the force sensing signal. Furthermore, when the physician releases the nerve hook, the hook remains in place, unaffected by the nerve's reaction force. A second beneficial effect is a fixed-force mode. After the physician releases the hook, the hook automatically maintains the nerve's traction with a fixed force. The user can set the magnitude, duration, and interval of the fixed force to maximize protection for the traction nerve. To further understand the features and technical contents of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are only for reference and illustration and are not intended to limit the present invention. 10: Force sensor 11: Filter 12: Conversion element 13: Encoder 14: Processing circuit 15: Speed ​​controller 151: First proportional integral controller 1511: Proportional controller 1512: Integral Controller 1513-1516: Arithmetic Unit 152: Torque limiter 153: Feedback gain controller 16: Strength Controller 161: Second proportional integral controller 1611: Proportional Controller 1612: Integral Controller 1613-1616: Arithmetic Unit 162: Position limiter 163: Feedback Gain Controller 17: Position controller 171: Arithmetic Unit 172: Proportional controller 2:Surgical instrument module 20: Transmission mechanism 21:Surgical instruments 23: Locking connecting rod F: Force sensing signal Vd: Speed ​​command signal R: Encoder measurement signal P: Position sensing signal V: Speed ​​sensing signal Ve: Speed ​​error signal Td: Torque command signal U1: General control signal Fd: Force command signal Fe: Force error signal Pd: Position command signal U2: General control signal FIG1 is a functional block diagram of a control system of a surgical instrument in a collaborative mode according to a first embodiment of the present invention. FIG. 2 is a schematic diagram of an embodiment of the surgical instrument module of FIG. 1 . FIG. 3 is a diagram showing the relationship between a force sensing signal and a velocity command signal according to the first embodiment of the present invention. FIG4 is a functional block diagram of the speed controller of FIG1 . FIG. 5 is a functional block diagram of a control system of a surgical instrument in a constant force mode according to a second embodiment of the present invention. FIG. 6 is a functional block diagram of the force controller of FIG. 5 . FIG. 7 is a functional block diagram of the position controller of FIG. 5 . The following is an explanation of the implementation of the "control system for surgical instruments" disclosed in the present invention through specific embodiments. Those skilled in the art can understand the advantages and effects of the present invention from the contents disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and the details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of the present invention. In addition, the drawings of the present invention are only simple schematic illustrations and are not depicted in actual size. It is stated in advance. The following embodiments will further explain the relevant technical content of the present invention in detail, but the disclosed content is not intended to limit the scope of protection of the present invention. It should be understood that although terms such as "first," "second," and "third" may be used herein to describe various components or signals, these components or signals should not be limited by these terms. These terms are primarily used to distinguish one component from another, or one signal from another. In addition, the term "or" as used herein may include any one or more combinations of the associated listed items, as appropriate. FIG1 is a functional block diagram of a surgical instrument control system in collaborative mode according to a first embodiment of the present invention. Referring to FIG1 , the control system includes a force sensor 10, a filter 11, a conversion element 12, an encoder 13, a processing circuit 14, and a speed controller 15. The surgical instrument module 2 includes a transmission mechanism 20 and a surgical instrument 21 connected to the transmission mechanism 20. The surgical instrument 21 is a nerve hook used to retract a nerve. The force sensor 10, filter 11, conversion element 12, encoder 13, processing circuit 14, speed controller 15, and transmission mechanism 20 are electrically connected together, either directly or indirectly. When a physician manually adjusts the nerve hook (surgical instrument 21) to retract the nerve, the force sensor 10 senses the physician's applied force, which, in conjunction with the speed controller 15, drives the nerve hook and retracts the nerve to a predetermined position at a stable speed. FIG2 is a schematic diagram of an embodiment of the surgical instrument module 2 of FIG1 . Referring to FIG2 , the transmission mechanism 20 is a single-degree-of-freedom DC motor drive device, and its base is connected to the locking link 23. The moving arm of the transmission mechanism 20 is connected to the surgical instrument 21 via the force sensor 10. The speed controller 15 is electrically connected to the transmission mechanism 20. When the speed controller 15 controls the rotation of the DC motor of the transmission mechanism 20, the rotation of the motor drives the moving arm of the transmission mechanism 20 to actuate, thereby moving the surgical instrument 21 to the desired position / orientation. The DC motor drive device shown in this figure and the locking link 23 are only one way to drive the surgical instrument 21. Other driving methods, such as a multi-axis robotic arm, can also be adopted in this case. The force sensor 10 is connected between the movable arm of the transmission mechanism 20 and the surgical instrument 21 and is configured to measure the force applied to the surgical instrument 21 to generate a force sensing signal F corresponding to the force applied to the surgical instrument 21. For example, the force sensor 10 may correspond to a six-axis force gauge. The force and torque signals provided by the six-axis force gauge can be used to calculate the magnitude and direction of the external force applied to the surgical instrument 21. An input terminal of the filter 11 is connected to an output terminal of the force sensor 10 . The filter 11 is configured to filter out ripples in the force sensing signal F. The conversion element 12 can be implemented, for example, as a single chip, and is connected to the filter 11. The conversion element 12 is configured to convert the force sensing signal F into a velocity command signal Vd. The conversion element 12 includes a dead zone, which includes an upper limit and a lower limit. When the force corresponding to the force sensing signal F is within the dead zone, the velocity command signal Vd generated by the conversion element 12 corresponds to zero velocity. The dead zone design prevents the generation of an erroneous velocity command signal Vd due to noise in the force sensing signal F when there is no force pulling the surgical instrument 21. Furthermore, when the physician releases the nerve hook, the nerve's reaction force falls within the dead zone, allowing the nerve hook to remain in place and not be displaced by the nerve's reaction force. FIG3 illustrates an exemplary relationship between a force sensing signal and a velocity command signal according to an embodiment of the present invention. Referring to FIG3 , the dead band of the conversion element 12 is defined as a range from -1.6 Newtons to 0.25 Newtons (N). When the force corresponding to the force sensing signal F is within the dead band of the conversion element 12, the velocity corresponding to the velocity command signal Vd is zero. When the force corresponding to the force sensing signal F is greater than 0.25 Newtons, the ratio between the velocity corresponding to the velocity command signal Vd and the amount by which the force sensing signal F exceeds 0.25 Newtons is approximately 5.33:1. When the force corresponding to the force sensing signal F is less than -1.6 Newtons, the ratio between the velocity corresponding to the velocity command signal Vd and the amount by which the force sensing signal F is less than -1.6 Newtons is approximately 5.33:1. The surgical instrument 21 can only be pulled to the desired position when the force corresponding to the force sensing signal F is greater than 0.25 Newtons or less than -1.6 Newtons. In fact, the range of the dead zone and the ratio of speed to force outside the dead zone need to be designed according to the dynamic characteristics of the hardware, which are different for each system. 1 , the encoder 13 is connected to the transmission mechanism 20 and configured to measure the rotation angle of the transmission mechanism 20 to generate an encoder measurement signal R. The input end of the processing circuit 14 is connected to the output end of the encoder 13 . The processing circuit 14 can be, for example, an integrated circuit such as a programmable logic controller circuit, a microprocessor circuit, or a microcontroller circuit, or a central processing unit. The processing circuit 14 is configured to calculate a position sensing signal P and a velocity sensing signal V of the surgical instrument 21 based on the encoder measurement signal R. Encoder 13 is connected to the motor to measure the motor's rotational angle and generate an encoder measurement signal R, which contains information about the motor's rotational angle. Processing circuit 14 calculates a position sensing signal P and a velocity sensing signal V of surgical instrument 21 based on the motor's rotational angle information. Position sensing signal P contains information about the position of surgical instrument 21, while velocity sensing signal V contains information about the velocity of surgical instrument 21. The input end of the speed controller 15 is connected to the output end of the conversion element 12 and the output end of the processing circuit 14. The speed controller 15 first calculates the difference between the speed command signal Vd generated by the conversion element 12 and the speed sensing signal V generated by the processing circuit 14 to generate a speed error signal. Then, the speed error signal Ve is calculated to generate a torque command signal Td. The speed controller 15 outputs a torque command signal Td to the transmission mechanism 20 to control the speed of the motor of the transmission mechanism 20. The faster the motor speed, the faster the lead screw speed, the faster the moving arm of the transmission mechanism 20 moves, and the faster the moving speed of the surgical instrument 21. Due to the addition of the dead zone, when the physician holds the nerve hook (surgical instrument 21) to pull the nerve, there is a small resistance to slightly resist the physician's force, thereby increasing the stability of the nerve pulling process. In addition, after pulling the nerve to the appropriate position, the nerve hook can be directly released, and the nerve hook can also remain in the released position, maintaining the desired nerve traction of the physician. Figure 4 is a functional block diagram of the speed controller of Figure 1. Referring to Figure 4 , the speed controller 15 includes a first proportional-integral controller 151, a torque limiter 152, and a feedback gain controller 153. The first proportional-integral controller 151, the torque limiter 152, and the feedback gain controller 153 can be implemented, for example, on a single chip. The first proportional-integral controller 151 includes a proportional controller 1511, an integral controller 1512, and a plurality of arithmetic units 1513, 1514, 1515, and 1516. The operation unit 1513 is connected to the conversion element 12 and the processing circuit 14. The operation unit 1513 is configured to calculate the difference between the speed command signal Vd and the speed sense signal V to generate a speed error signal Ve. The operation unit 1513 is connected to the proportional controller 1511 and another operation unit 1514. The proportional controller 1511 is configured to multiply the speed error signal Ve by a proportional gain to generate a proportional control signal for the proportional controller 1511. The operation unit 1514 is connected to the other operation unit 1513 and the output terminal of the feedback gain controller 153. The operation unit 1514 is configured to calculate the difference between the speed error signal Ve and the output signal of the feedback gain controller 153 to generate an output signal of the operation unit 1514. The integral controller 1512 is connected to the operation unit 1514. The integral controller 1512 is configured to first integrate the output signal of the operation unit 1514 and then multiply the integrated result by the integral gain to generate an integral control signal for the integral controller 1512. The operation unit 1515 is connected to the proportional controller 1511 and the integral controller 1512 . The operation unit 1515 is configured to calculate the sum of the proportional control signal of the proportional controller 1511 and the integral control signal of the integral controller 1512 to generate a total control signal U1 . The purpose of the proportional controller 1511 is to provide a fast dynamic response, and the purpose of the integral controller 1512 is to eliminate steady-state errors. In practice, the proportional gain and integral gain must be designed based on the dynamic characteristics of the hardware, which varies from system to system. The torque limiter 152 is connected to the computing unit 1515. It defines an upper torque limit and a lower torque limit. When the value corresponding to the total control signal U1 does not exceed the upper torque limit or does not fall below the lower torque limit, the torque corresponding to the torque command signal Td output by the torque limiter 152 is equal to the value corresponding to the total control signal U1 output by the computing unit 1515. When the value corresponding to the total control signal U1 exceeds the upper torque limit, the torque corresponding to the torque command signal Td output by the torque limiter 152 is equal to the upper torque limit. When the value corresponding to the total control signal U1 falls below the lower torque limit, the torque corresponding to the torque command signal Td output by the torque limiter 152 is equal to the lower torque limit. Operation unit 1516 is connected to operation unit 1515, torque limiter 152, and feedback gain controller 153. Operation unit 1516 is configured to calculate the difference between the total control signal U1 from operation unit 1515 and the torque command signal Td from torque limiter 152 to generate an output signal from operation unit 1516. Feedback gain controller 153 is configured to multiply the output signal from operation unit 1516 by a feedback gain to generate an output signal from feedback gain controller 153. Specifically, torque limiter 152, operation unit 1516, and feedback gain controller 153 together form an anti-windup compensator, the primary purpose of which is to limit excessive error accumulation in integral controller 1512. When the total control signal U1 exceeds the usable range, feedback gain controller 153 prevents the integral controller 1512 from excessively integrating the error, maintaining the stability of the integral component. This also accelerates the response of the control system when the total control signal U1 returns to the usable range. In summary, during the coordinated nerve hook's nerve traction process, the physician's manual traction force measured by force sensor 10 is filtered by filter 11 and then converted by conversion element 12 into a target speed for the nerve hook. Finally, speed controller 15 adjusts the speed of the nerve hook during the nerve traction process, ensuring that it consistently reaches the target speed. When the speed controller 15 drives the nerve hook at a stable speed to pull the nerve to the predetermined position, the doctor can release the nerve hook. After the nerve hook is released, the control system can be used in a constant force mode to automatically maintain the nerve traction with a fixed force. FIG5 is a functional block diagram of a control system for a surgical instrument according to a second embodiment of the present invention in constant force mode. FIG5 differs from FIG1 in that the control system in FIG5 includes a force controller 16 and a position controller 17 in addition to a speed controller 15 , and that the speed controller 15 in FIG5 is identical to the speed controller 15 in FIG4 . In constant force mode, the processing circuit 14 calculates the position sensing signal P and the velocity sensing signal V based on the encoder measurement signal R. The processing circuit 14 also generates a force command signal Fd based on the user's settings. The force corresponding to the force command signal Fd is a constant value. The force controller 16 first calculates the difference between the force sensing signal F and the force command signal Fd to generate a force error signal. It then generates the position command signal Pd based on the force error signal. It should be noted that the force sensing signal F in this case is the force exerted by the nerve on the nerve hook as measured by the force sensor 10. The position controller 17 first calculates the difference between the position command signal Pd generated by the force controller 16 and the position sensing signal P generated by the processing circuit 14 to generate a position error signal Pe (see FIG. 7 ), and then calculates a velocity command signal Vd based on the position error signal Pe. FIG6 is a functional block diagram of a force controller according to an embodiment of the present invention. Referring to FIG6 , the force controller 16 includes a second proportional-integral controller 161, a position limiter 162, and a feedback gain controller 163. The second proportional-integral controller 161, the position limiter 162, and the feedback gain controller 163 can be implemented, for example, on a single chip. The second proportional-integral controller 161 includes a proportional controller 1611, an integral controller 1612, and a plurality of computing units 1613, 1614, 1615, and 1616. The computing unit 1613 is connected to the force sensor 10 and the processing circuit 14. The computing unit 1613 is configured to calculate the difference between the force sensing signal F and the force command signal Fd to generate a force error signal Fe. The proportional controller 1611 is connected to the computing unit 1613. The proportional controller 1611 is configured to multiply the force error signal Fe by a proportional gain to generate a proportional control signal for the proportional controller 1611. Operation unit 1614 is connected to another operation unit 1613 and the output terminal of feedback gain controller 163. Operation unit 1614 is configured to calculate the difference between the force error signal Fe and the output signal of feedback gain controller 163 to generate an output signal of operation unit 1614. Integral controller 1612 is connected to operation unit 1614. Integral controller 1612 first integrates the output signal of operation unit 1614 and then multiplies the integral result by the integral gain to generate an integral control signal for integral controller 1612. Operation unit 1615 is connected to proportional controller 1611 and integral controller 1612. Operation unit 1615 is configured to calculate the sum of the proportional control signal of proportional controller 1611 and the integral control signal of integral controller 1612 to generate a total control signal U2. In practice, the proportional gain and integral gain must be designed based on the dynamic characteristics of the hardware and vary from system to system. The position limiter 162 is connected to the arithmetic unit 1615. It defines an upper position limit and a lower position limit. When the value corresponding to the total control signal U2 does not exceed the upper position limit or fall below the lower position limit, the position corresponding to the position command signal Pd output by the position limiter 162 is equal to the value corresponding to the total control signal U2 output by the arithmetic unit 1615. When the value corresponding to the total control signal U2 exceeds the upper position limit, the position corresponding to the position command signal Pd output by the position limiter 162 is equal to the upper position limit. When the value corresponding to the total control signal U2 falls below the lower position limit, the position corresponding to the position command signal Pd output by the position limiter 162 is equal to the lower position limit. Specifically, the position limiter 162, the operation unit 1616, and the feedback gain controller 163 together form an anti-windup compensator with two purposes: first, to limit excessive error accumulation in the integral controller 1612. When the total control signal U2 exceeds the usable range, the feedback gain controller 163 prevents the integral controller 1612 from excessively integrating the error, maintaining the stability of the integral component. This also accelerates the response of the control system when the total control signal U2 returns to the usable range. Second, to limit the maximum displacement of the nerve hook of the surgical instrument 21 under fixed force control, preventing excessive movement of the nerve hook and potential injury to the patient due to operator mis-touch, interference, or other unexpected conditions. The operation unit 1616 is connected to another operation unit 1615, the position limiter 162, and the feedback gain controller 163. The operation unit 1616 is configured to calculate the difference between the total control signal U2 of the other operation unit 1615 and the position command signal Pd of the position limiter 162 to generate an output signal of the operation unit 1616. The feedback gain controller 163 is configured to multiply the output signal of the operation unit 1616 by the feedback gain to generate an output signal of the feedback gain controller 163 . FIG7 is a functional block diagram of a position controller provided according to an embodiment of the present invention. Referring to FIG7 , the position controller 17 includes an arithmetic unit 171 and a proportional controller 172. The arithmetic unit 171 and the proportional controller 172 can be implemented, for example, by a single chip. The arithmetic unit 171 is connected to the force controller 16 (i.e., the output of the position limiter 162), the output of the processing circuit 14, and the input of the proportional controller 172. The arithmetic unit 171 is configured to calculate the difference between the position command signal Pd from the position limiter 162 and the position sensing signal P from the processing circuit 14 to generate a position error signal Pe. The proportional controller 172 is connected to the output of the arithmetic unit 171. The proportional controller 172 is configured to multiply the position error signal Pe by a proportional gain to generate a speed command signal Vd. The proportional controller 172 outputs the speed command signal Vd to the speed controller 15. [Beneficial Effects of Embodiments] One of the beneficial effects of the present invention is that the control system of the surgical instrument provided by the present invention, in collaborative mode, can assist the surgeon in guiding the nerve hook to a predetermined position at a stable speed during nerve hook retraction. The dead zone design of the speed controller prevents erroneous speed command signals from being generated due to noise in the force sensing signal. When the nerve hook reaches its target position and the surgeon releases the nerve hook, the nerve's reaction force is within the dead zone, allowing the nerve hook to remain in place and not be displaced by the reaction force. The second beneficial effect of the present invention is that the control system of the surgical instrument provided by the present invention can activate the constant force mode to automatically maintain the nerve traction force after the nerve hook moves to the predetermined position. Even if the nerve hook encounters a sudden external force collision, the force controller will help keep the force of the nerve hook pulling the nerve in a roughly constant state, preventing the nerve hook from suddenly pulling the nerve with too much force. When the nerve hook encounters a sudden external force collision and is displaced, the position controller can limit the displacement of the nerve hook to prevent the nerve hook from excessively displacing and causing damage to the nerve. The constant force mode can set the size, time and interval of the constant force, allowing the doctor to perform nerve traction with precise force, and then intermittently relax at the appropriate time to avoid nerve damage. The contents disclosed above are only preferred feasible embodiments of the present invention and do not limit the scope of the patent application of the present invention. Therefore, all equivalent technical changes made using the contents of the description and drawings of the present invention are included in the scope of the patent application of the present invention. 10: Force sensor 11: Filter 12: Conversion element 13: Encoder 14: Processing circuit 15: Speed ​​controller 2:Surgical instrument module 20: Transmission mechanism 21:Surgical instruments F: Force sensing signal Vd: Speed ​​command signal R: Encoder measurement signal V: Speed ​​sensing signal P: Position sensing signal Td: Torque command signal

Claims

1. A control system for a surgical instrument, adapted to control a transmission mechanism to drive a surgical instrument, the control system comprising: a force sensor connected between the surgical instrument and the transmission mechanism and configured to measure the force applied to the surgical instrument to generate a force sensing signal; a conversion element configured to convert the force sensing signal into a speed command signal, wherein the conversion element includes a dead zone, and when the force sensing signal is within the dead zone, the speed corresponding to the speed command signal is zero; an encoder connected to the transmission mechanism and configured to measure the rotation angle of the transmission mechanism to generate an encoder measurement signal; a processing circuit configured to generate a position sensing signal and a speed sensing signal of the transmission mechanism based on the encoder measurement signal; a speed controller configured to calculate the difference between the speed command signal and the speed sensing signal to generate a speed error signal, and the speed error signal is calculated by the speed controller to generate a torque command signal.

2. The control system of the surgical instrument according to claim 1 further includes a filter connected between the force sensor and the conversion element to filter out ripples in the force sensing signal.

3. A control system for a surgical instrument as described in claim 1, wherein the speed controller includes a first proportional-integral controller, at least one operation unit, a feedback gain controller and a torque limiter, the first proportional-integral controller is connected to the torque limiter, the torque limiter outputs the torque command signal to the transmission mechanism, the torque limiter is configured to limit the upper and lower limits of the torque of the transmission mechanism, and the output of the torque limiter is also processed by the operation unit and the feedback gain controller and input into the integral controller for integral saturation compensation.

4. The control system of the surgical instrument as described in claim 1 also includes a force controller, the processing circuit generates a force command signal, and the force corresponding to the force command signal is a constant value. The force controller is configured to calculate the difference between the force sensing signal and the force command signal to generate a force error signal, and the force error signal is calculated by the force controller to generate a position command signal.

5. A control system for a surgical instrument as described in claim 4, wherein the force controller includes a second proportional-integral controller, a feedback gain controller, at least one operation unit and a position limiter, the second proportional-integral controller is connected to the position limiter, the position limiter outputs the position command signal, the position limiter is configured to limit the upper and lower limits of the displacement of the transmission mechanism, and the output of the position limiter is also processed by the operation unit and the feedback gain controller and input into the integral controller for integral saturation compensation.

6. The control system of the surgical instrument as described in claim 4 further includes a position controller, wherein the processing circuit is configured to generate the position sensing signal of the transmission mechanism according to the rotation angle, and the position controller is configured to calculate the difference between the position command signal and the position sensing signal to generate a position error signal, and the position error signal is calculated by the position controller to generate the speed command signal.

7. The control system of the surgical instrument according to claim 6, wherein the position controller includes a proportional controller, the input of the proportional controller is the position error signal, and the proportional controller outputs the speed command signal to the speed controller.

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