Series-parallel robot system with three-dimensional adjustable remote center of motion and control method thereof

Abstract

The present disclosure relates to the technical field of medical robots, in particular to a three-dimensional adjustable remote center of motion series-parallel robot system and a control method thereof, the control method comprising: calculating a first control component based on an integral barrier Lyapunov function, according to a position tracking error and a preset motor position safety boundary; calculating a second control component according to a speed tracking error; calculating a third control component based on a dynamics model of the series-parallel robot system, according to a desired speed value and a desired acceleration value; obtaining a total control instruction based on the first control component, the second control component and the third control component; and outputting the total control instruction to each motor driving element to drive the motor to move. The above technical solution has the ability to dynamically adjust the position of the remote center of motion during the operation, ensures high-precision trajectory tracking and strict boundedness of errors through a composite control strategy, and significantly improves the safety and flexibility of the operation.

Description

Technical Field

[0001] This disclosure relates to the field of medical robot technology, specifically to a serial and parallel robot system with a three-dimensional adjustable remote motion center and its control method. Background Technology

[0002] Minimally invasive surgery, especially delicate procedures in ophthalmology and neurosurgery, places extremely high demands on the precision, safety, and dexterity of surgical robots. In these surgeries, surgical instruments often need to rotate around a fixed external point, known as the Remote Center of Motion (RCM). Maintaining the instrument's movement around the RCM minimizes trauma to the incision tissue and is a key function of surgical robots.

[0003] Existing methods for implementing remote motion centers in surgical robots mainly fall into two categories: mechanical passive remote motion center mechanisms and virtual constraint active remote motion center mechanisms. While mechanical passive remote motion center mechanisms are structurally reliable and simple to control, the position of their remote motion center point is determined during mechanical design and cannot be adjusted intraoperatively. When surgery requires changing the incision location or performing multi-point operations, cumbersome mechanical repositioning or replacement of the entire instrument module is necessary, severely impacting the smoothness and efficiency of the surgical procedure and failing to meet the need for flexible intraoperative adjustments.

[0004] Furthermore, existing surgical robot control methods mostly employ traditional proportional-integral-derivative (PID) control algorithms. While PID control is simple in structure and easy to implement, it cannot guarantee that the system's state variables (such as joint position errors) are strictly limited within safety boundaries. In precision surgery, this means there is a potential risk that tools may exceed preset safety limits and collide with patient tissues or equipment. Summary of the Invention

[0005] To address the problems in related technologies, this disclosure provides a serial and parallel robot system with a three-dimensional adjustable remote motion center and its control method.

[0006] In a first aspect, this disclosure provides a control method for a serial-parallel robot system with a three-dimensional adjustable remote motion center. The serial-parallel robot system includes three joint modules connected in series and arranged perpendicularly to each other. The three joint modules include a first joint module, a second joint module, and a third joint module. The first and second joint modules have identical structures. Each joint module includes two parallel motors and a rigid linkage mechanism. The rigid linkage mechanism is used to output the translational degrees of freedom of each of the two motors as the translational and rotational degrees of freedom of the joint module. The third joint module includes a fifth motor and surgical tools. The control method includes:

[0007] S1: Obtain the desired pose of the surgical instrument tip in the current cycle;

[0008] S2: Based on the inverse kinematics of the serial-parallel robot system, the desired pose is calculated as the desired position value of each motor drive element in the current cycle. And based on the desired position value By comparing the expected position value with the historical cycle values, the expected velocity value of the current cycle is determined. and expected acceleration value ;

[0009] S3: Real-time acquisition of the current actual position value of each motor drive component. and the current actual speed value ;

[0010] S4: Calculate the position tracking error for the current cycle. and speed tracking error ;

[0011] S5: Based on the integral barrier Lyapunov function, according to the position tracking error... and the preset motor position safety boundary Calculate the first control component ;

[0012] S6: Based on the speed tracking error Calculate the second control component ;

[0013] S7: Based on the dynamic model of the serial-parallel robot system, according to the desired velocity value... and expected acceleration value Calculate the third control component ;

[0014] S8: Based on the first control component Second control component and the third control component Receive the master control command ;

[0015] S9: The overall control command The output is sent to each motor drive component to drive the motor to move.

[0016] In one embodiment of this disclosure, the first control component is used... Second control component and the third control component Receive the master control command ,include:

[0017] Based on the first control component Second control component and the third control component Any combination of the following will produce the master control command. :

[0018] Combination 1: ;

[0019] Combination 2: ;

[0020] Combination 3: .

[0021] In one embodiment of this disclosure, a general control command is output to each motor drive element. Same or different.

[0022] In one embodiment of this disclosure, a general control command is output to the motor drive elements of two motors in the same joint module. The same, and different joint modules, have the same total control command input to the motor drive elements of the two motors. different.

[0023] In one embodiment of this disclosure, the first control component The calculation formula is:

[0024]

[0025] in, Let i be the motor position safety boundary for the i-th motor. Let be the upper limit of the position constraint for the i-th motor. This is a preset constant; Let be the position tracking error of the i-th motor; The speed tracking error of the i-th motor; This represents the current actual position value of the i-th motor; This indicates a pseudo-inverse operation; .

[0026] In one embodiment of this disclosure, the second control component The calculation formula is:

[0027]

[0028] in, This is the damping gain parameter.

[0029] In one embodiment of this disclosure, the third control component The calculation formula is:

[0030]

[0031] in, It is the Coriolis force matrix. It is the gravity term. It is the mass matrix, calculated based on the dynamic model of the series-parallel robot system.

[0032] Secondly, this disclosure provides a serial-parallel robot system with a three-dimensional adjustable remote motion center. The serial-parallel robot system includes three joint modules connected in series and arranged perpendicularly to each other. The three joint modules include a first joint module, a second joint module, and a third joint module. The first and second joint modules have the same structure. Each joint module includes two motors arranged in parallel and a rigid linkage mechanism. The rigid linkage mechanism is used to output the translational degrees of freedom of the two motors as the translational and rotational degrees of freedom of the joint module. The third joint module includes a fifth motor and a surgical tool. The fifth motor is used to adjust the feed amount of the surgical tool along the tool axis.

[0033] The serial-parallel robot system further includes a controller configured to perform the control method as described in any of the first aspects.

[0034] In one embodiment of this disclosure, the two motors and the fifth motor are micrometer-level precision motors or nanometer-level precision motors.

[0035] In one embodiment of this disclosure, the serial-parallel robot system is used for ophthalmic surgery, the surgical tool is an ophthalmic microsurgical instrument, and the remote motion center point is located within the eyeball region.

[0036] Thirdly, embodiments of this disclosure provide an electronic device including a memory and a processor, wherein the memory is used to store one or more computer instructions, wherein the one or more computer instructions are executed by the processor to implement the method as described in any of the second or third aspects.

[0037] Fourthly, this disclosure provides a computer-readable storage medium having computer instructions stored thereon, which, when executed by a processor, implement the method described in any of the second or third aspects.

[0038] The technical effects provided by the embodiments of this disclosure may include the following beneficial effects:

[0039] According to the technical solution provided in this disclosure, by using three series-connected joint modules in conjunction with a composite control strategy, a three-dimensional adjustable remote motion center can be realized. At the same time, the Lyapunov function constrains the position tracking error by utilizing the integral barrier, and combined with feedforward compensation and damping control, it has the ability to dynamically adjust the position of the remote motion center during surgery. Meanwhile, the composite control strategy ensures high-precision trajectory tracking and strict boundedness of error, significantly improving surgical safety and operational flexibility.

[0040] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0041] Other features, objects, and advantages of this disclosure will become more apparent from the following detailed description of non-limiting embodiments, taken in conjunction with the accompanying drawings. The following is a description of the accompanying drawings.

[0042] Figure 1 A schematic diagram of a serial-parallel robot system with a three-dimensional adjustable remote motion center according to an embodiment of the present disclosure is shown.

[0043] Figure 2 A kinematic model of a system comprising a first joint module and a third joint module according to an embodiment of the present disclosure is shown.

[0044] Figure 3 A flowchart illustrating a control method for a serial-parallel robot system with a three-dimensional adjustable remote motion center according to an embodiment of the present disclosure is provided.

[0045] Figures 4a to 4e A schematic diagram of simulation results is shown for a control method of a serial-parallel robot system with a three-dimensional adjustable remote motion center according to an embodiment of the present disclosure.

[0046] Figure 5 A structural block diagram of an electronic device according to an embodiment of the present disclosure is shown.

[0047] Figure 6 A schematic diagram of the structure of a computer system suitable for implementing the method according to embodiments of the present disclosure is shown. Detailed Implementation

[0048] In the following, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings to enable those skilled in the art to readily implement them. Furthermore, for clarity, portions unrelated to the description of exemplary embodiments have been omitted from the drawings.

[0049] In this disclosure, it should be understood that terms such as “comprising” or “having” are intended to indicate the presence of features, figures, steps, behaviors, components, parts or combinations thereof disclosed in this specification, and are not intended to exclude the possibility of the presence or addition of one or more other features, figures, steps, behaviors, components, parts or combinations thereof.

[0050] It should also be noted that, unless otherwise specified, the embodiments and features described in this disclosure can be combined with each other. This disclosure will now be described in detail with reference to the accompanying drawings and embodiments.

[0051] In existing technologies, remote motion center mechanisms (RCMs) are used in minimally invasive surgery to constrain the rotation of surgical instruments around the incision point. However, existing mechanical passive mechanisms cannot adjust their position, while virtual constraint active mechanisms suffer from complex and singular control issues. For example, in ophthalmic surgery, the RCM point needs to be dynamically adjusted according to the patient's eye position, but traditional mechanical structures require repositioning, and virtual control carries the risk of trajectory deviation.

[0052] In view of the above-mentioned shortcomings, the control method of the serial-parallel robot system with three series-connected joint modules and a composite control strategy in this application realizes a three-dimensional adjustable remote motion center. At the same time, it uses the integral barrier Lyapunov function to constrain the position tracking error, and combines feedforward compensation and damping control to have the ability to dynamically adjust the position of the remote motion center during surgery. Meanwhile, the composite control strategy ensures high-precision trajectory tracking and strict boundedness of error, significantly improving surgical safety and operational flexibility.

[0053] Figure 1 A schematic diagram of a serial-parallel robot system with a three-dimensional adjustable remote motion center according to an embodiment of the present disclosure is shown.

[0054] like Figure 1 As shown, the serial and parallel robot system of the three-dimensional adjustable remote motion center includes:

[0055] Three joint modules are connected in series and arranged perpendicularly to each other. These three modules include a first joint module 1, a second joint module 2, and a third joint module 3. The first and second joint modules 1 and 2 have identical structures. Each joint module includes two parallel motors and a rigid linkage mechanism. The rigid linkage mechanism outputs the translational degrees of freedom of each of the two motors as the translational and rotational degrees of freedom of the joint module. The third joint module 3 includes a fifth motor 31 and a surgical tool 4. The fifth motor 31 is used to adjust the feed of the surgical tool 4 along its axis. The two motors in the first joint module 1 are denoted as 11 and 12, and the two motors in the second joint module 2 are denoted as 21 and 22. The displacement generated by the synchronous movement of two motors, such as 11 and 12, is output as the translational degree of freedom of the first joint module 1. The displacement difference generated by the asynchronous movement of 11 and 12 is output as the rotational degree of freedom of the first joint module 1, thereby driving the movement of the second joint module 2. Similarly, the synchronous and asynchronous movements of 21 and 22 are output as another translational and another rotational degree of freedom, thereby driving the movement of the third joint module 3.

[0056] In this disclosure, a rigid linkage mechanism refers to a mechanism that converts the linear motion of two motors into a composite motion of translation and rotation of a joint module through a parallelogram linkage or a slider-crank mechanism, for example, using a cross ball screw structure to achieve two-axis linkage. Specifically, such as... Figure 1 As shown, the rigid linkage mechanism includes a fixed plate 5, on which a fixing member 6 and a slide rail 8 are mounted. A sliding member 7 is slidably connected to the slide rail 8. The fixing member 6 and the sliding member 7 are each hinged to the output end of a motor.

[0057] The following is a kinematic analysis of the serial and parallel robot system of the three-dimensional adjustable remote motion center disclosed in this application. To simplify the analysis, a kinematic model of the system consisting of the first joint module and the third joint module is first constructed, and then further extended to a kinematic model of three joint modules.

[0058] Figure 2 A kinematic model of a system comprising a first joint module and a third joint module according to an embodiment of the present disclosure is shown.

[0059] like Figure 2As shown, point A is the system base point. A base coordinate system is constructed with point A as the base point. The X-axis of the base coordinate system is in the same direction as the displacement of motors 11 and 12, with the positive X-axis pointing towards the output end of the first joint module. The positive Y-axis points from motor 12 towards the side of motor 11. Point B is the first end of the rigid linkage mechanism, which is the output integration point of motors 11 and 12, specifically the midpoint of the line connecting motors 11 and 12 with the hinge point of the rigid linkage mechanism. Point C is the second end of the rigid linkage mechanism, which is a point on the tool axis translated from point B. Point D is the end point of the surgical tool. Local coordinate systems are constructed with points B and C respectively. For example, the Y-axis of the local coordinate system constructed with point B is in the direction of the hinge point connection line, with the positive Y-axis and positive X-axis in the same direction as the base coordinate system. The Y-axis of the local coordinate system constructed with point C is in the direction of the tool axis, with the positive Y-axis and positive X-axis in the same direction as the base coordinate system. A tool coordinate system is constructed with point D as the reference point. The Y-axis of the tool coordinate system is oriented along the tool axis, and the positive Y-axis is oriented in the same direction as the positive X-axis of the base coordinate system. The positive Z-axis directions of the base coordinate system, local coordinate system, and tool coordinate system can be determined according to the right-hand rule. The construction of the above coordinate system is only illustrative, and those skilled in the art can construct it in other forms based on existing technology, which will not be elaborated here.

[0060] in, , The length of the hinge point in the X-axis direction in the base coordinate system refers to the horizontal displacement of motors 11 and 12. Refers to the equivalent displacement output by the first joint module. This refers to the rotation angle output by the first joint module. dm is the distance between the two hinge points when motors 11 and 12 have not moved; here, it refers to the vertical distance between motors 11 and 12. Indicates the length of the end effector (rigid linkage mechanism); This indicates the length from the midpoint of the linear stroke of the fifth motor to the end of the tool; The feed amount is adjusted by the fifth motor. In this disclosure, / 2; .

[0061] The homogeneous transformation matrix of point D at the end of the tool with respect to point A is expressed as: Specifically, it takes the following form:

[0062] .

[0063] In the overall serial-parallel robot configuration, the structure of the second joint module is the same as that of the first joint module. Therefore, a homogeneous transformation matrix for the second joint module is defined. , and The expressions are the same. The kinematic model of the overall serial-parallel robot can be equivalently composed of the following two steps: for the homogeneous transformation matrix of the first joint module , and And L5 is set to 0; the second joint module rotates 90° around the y-axis ( It is installed at the end of the first joint module. Therefore, the final homogeneous transformation matrix of the serial-parallel robot is... :

[0064] ,

[0065] ,

[0066] .

[0067] in, Refers to the equivalent displacement output by the second joint module. Refers to the rotation angle output by the second joint module; / 2; ; , This refers to the horizontal displacement of motors 21 and 22.

[0068] The inverse kinematics solution process is as follows:

[0069] Based on homogeneous transformation matrix In the robot's base coordinate system, the position coordinates of the end point H of the surgical instrument are:

[0070] ,

[0071] ,

[0072] .

[0073] In the robot's base coordinate system, the expression for the rotation angle of the surgical instrument is:

[0074] ,

[0075] Therefore, we obtain The expression:

[0076] , .

[0077] Further , , Solving for the problem, we get:

[0078] ,

[0079] ,

[0080] .

[0081] Further obtain , , , The expression:

[0082] + ; ; ;

[0083] ;

[0084] Therefore, given the end-effector pose (i.e., the position coordinates of the end-effector H and the orientation (rotation angle) of the surgical tool), the displacement of the five motors can be obtained based on inverse kinematics.

[0085] For the inverse velocity mapping of this robot system, the Jacobian matrix is ​​calculated to... , , and , Find their relative values ​​separately to The partial derivative can be used to obtain the Jacobian matrix of the 5×5 series-parallel robot. J 2. Since the matrix is ​​too large, we only need to take its determinant, and we get:

[0086] .

[0087] Considering and The range is all Between, and excluding the boundary. Therefore This holds true. Therefore, the Jacobian matrix is ​​known. J 2 is a non-singular matrix. Therefore, for a robot with this configuration, there are no singular points in its control space, and for any end-effector pose within its working range, there is always a unique motor displacement state corresponding to it, and vice versa.

[0088] Figure 3 A flowchart illustrating a control method for a serial-parallel robot system with a three-dimensional adjustable remote motion center according to an embodiment of the present disclosure is provided.

[0089] like Figure 3As shown, the control method for the serial-parallel robot system with the three-dimensional adjustable remote motion center includes the following steps:

[0090] S1: Obtain the desired pose of the surgical instrument tip in the current cycle;

[0091] S2: Based on the inverse kinematics of the serial-parallel robot system, the desired pose is calculated as the desired position value of each motor drive element in the current cycle. And based on the desired position value By comparing the expected position value with the historical cycle values, the expected velocity value of the current cycle is determined. and expected acceleration value ;

[0092] S3: Real-time acquisition of the current actual position value of each motor drive component. and the current actual speed value ;

[0093] S4: Calculate the position tracking error for the current cycle. and speed tracking error ;

[0094] S5: Based on the Lyapunov function with integration barrier According to the position tracking error and the preset motor position safety boundary Calculate the first control component The first control component This is used to constrain the position tracking error within the motor position safety boundary;

[0095] S6: Based on the speed tracking error Calculate the second control component The second control component Used to provide system damping;

[0096] S7: Based on the dynamic model of the serial-parallel robot system, according to the desired velocity value... and expected acceleration value Calculate the third control component The third control component Nonlinear dynamic effects used in feedforward compensation systems;

[0097] S8: Based on the first control component Second control component and the third control component Receive the master control command ;

[0098] S9: The overall control command The output is sent to each motor drive component to drive the motor to move.

[0099] In this disclosure, the structure and kinematic model of the serial and parallel robot system with a three-dimensional adjustable remote motion center can be referred to the description in the above embodiments section, and will not be repeated here.

[0100] In this disclosed method, the surgeon sets the desired pose of the surgical tool's end effector in the current cycle on the surgical navigation system or main control terminal, including the position coordinates of the end effector point H. , , and the posture of surgical instruments After receiving the end-effector pose, the controller invokes the inverse kinematics algorithm to calculate the 6-dimensional pose information (position and orientation) of the end-effector into the expected position values ​​of the robot's five motors in the current cycle. The controller also considers the desired position value for the current cycle. Using the expected position value from the previous cycle, the expected velocity value for the current cycle is calculated through the numerical difference method. and expected acceleration value At the start of the current control cycle, the high-precision encoders of each motor of the robot synchronously sample and measure the current actual position value of the motor in real time. and the current actual speed value Among them, the current actual speed value Typically, this is obtained by differentially analyzing continuous position signals. After receiving the reference values ​​(i.e., desired position, desired velocity, and desired acceleration) and the actual state (i.e., current actual position and current actual velocity) for the current cycle, the controller calculates the three control components in parallel and finally synthesizes the total control force.

[0101] Specifically, the position tracking error is first calculated. and speed tracking error .

[0102] Next, the first control component is calculated. , or called Constraint Feedback Item The controller tracks the position error of each motor. and its corresponding security boundary Substitute a preset Within the function, an algorithmic "virtual potential well" is constructed. When the error approaches the boundary, a huge virtual force is generated to push it back, ensuring that the actual position of each motor never exceeds its mechanical travel limit—a core guarantee of safety. The final result is... Constraint Feedback Item .

[0103] Calculate the second control component , or speed error damping term Speed ​​tracking error Multiply by a negative gain matrix This is equivalent to a damper, which suppresses system oscillations and speeds up the response.

[0104] Calculate the third control component , or model feedforward compensation term The controller operates based on the current robot's kinematic model (including the mass matrix, Coriolis matrix, and gravity matrix) and the current reference acceleration. It calculates a feedforward force in real time. This force is used to precisely counteract the effects of the robot's own inertia, the centrifugal force coupled between joints, and gravity on motion. It gives the controller predictive capabilities, as if it were dragging an ideal robot without gravity or inertia, thereby significantly improving tracking accuracy and response speed.

[0105] Then based on Constraint Feedback Item Speed ​​error damping term and model feedforward compensation term The combination of these commands yields the overall control command. ,in, , A negative value indicates negative feedback. A positive value indicates feedforward compensation.

[0106] The final synthesized overall control command The signals are sent to the drivers of the individual joint motors, which convert the digital control signals into corresponding current or voltage outputs, driving the motors to generate precise force and motion. This output will be maintained throughout the current cycle until a new command arrives for the next cycle.

[0107] In this disclosure, the current period refers to a fixed, cyclical time segment from when the controller starts reading sensor data until it calculates and outputs the control command. The length of this time segment is the control step size.

[0108] After the current cycle ends, the controller immediately enters the next control cycle. It will repeat steps S1 to S9 with the latest sensor sampling values ​​and the new reference values. This process runs continuously at a very high frequency (e.g., a period of 30ms), forming a closed loop, constantly correcting errors, and ensuring that the robot's end effector accurately tracks the predetermined surgical path.

[0109] In one embodiment of this disclosure, the first control component The calculation formula is:

[0110] ,

[0111] in, Let i be the motor position safety boundary for the i-th motor. Let be the upper limit of the position constraint for the i-th motor. This is a preset constant; Let be the position tracking error of the i-th motor; The speed tracking error of the i-th motor; This represents the current actual position value of the i-th motor; This indicates a pseudo-inverse operation; .

[0112] In one embodiment of this disclosure, the second control component The calculation formula is:

[0113] ,

[0114] in, This is the damping gain parameter.

[0115] In one embodiment of this disclosure, the third control component The calculation formula is:

[0116] ,

[0117] in, It is the Coriolis force matrix. It is the gravity term. It is the mass matrix, calculated based on the dynamic model of the series-parallel robot system.

[0118] In this disclosure, the dynamic equations of the robot system are established using the Newton-Euler equations or the Lagrange equations:

[0119] ,

[0120] in, It is a generalized force vector.

[0121] This dynamic equation is a mathematical description of the controlled object (robot) based on physical laws (mechanics). It reveals the physical effects of inertia, Coriolis force, centrifugal force, and gravity in the robot's motion, and their relationship to the overall control commands. The causal relationship between them.

[0122] To calculate the system's mass matrix, considering that the first joint module is mounted as a base and its mass is negligible, we define the mass of the second joint module as m1, the mass of the fifth motor as m2, and the mass of the end effector and surgical tools as m3. We also consider the inertia tensors of the second joint module and the fifth motor. Each is arranged along the main axis of its main structure:

[0123] ,

[0124] Next, consider the following translation Jacobian matrix:

[0125] And the following rotation Jacobian matrix (from Mapped to ):

[0126] .

[0127] Therefore, the mass matrix It can be constructed in the following form:

[0128] .

[0129] Among them, the configuration-related inertia tensor and This can be expressed as:

[0130] ,

[0131] Wherein, rotation matrix and Its function is to include configuration-independent inertia matrices. and Rotate according to the current angular configuration to construct an inertial tensor related to the current attitude configuration. ,

[0132] .

[0133] In summary, the final result of the robot mass matrix can be written as:

[0134] ,

[0135] in, ,

[0136] ,

[0137] ,

[0138] .

[0139] Centrifugal and Coriolis force terms This can be represented using the Christopher symbol, namely:

[0140] ,

[0141] .

[0142] Where n=5 is the number of motors. The definition is as follows:

[0143] ,

[0144] in, This represents the element in the i-th row and j-th column of the quality matrix M.

[0145] The gravity vector is generally defined as Considering that the first joint module is typically fixed as the robot's base, while the second joint module is directly mounted on top of the first joint module, the first thing to consider is the center of gravity of the second joint module (as mentioned earlier, its mass is defined as m1). Simultaneously, the distance from the horizontal axis of the first joint module to this center of gravity also needs to be considered. From a kinematic perspective, assuming the position of the first joint module, i.e., the base, is known, we modify it by substituting its distance from the center of gravity. ,have to:

[0146] ,

[0147] Gravity only affects this vector. Components, then potential energy function Part 1 :

[0148] ,

[0149] in, This is the gravitational influence factor.

[0150] Considering the fifth motor at the end, its displacement from the center of gravity of the second joint module is defined as... Then the position of the centroid vector of the fifth motor can be expressed as:

[0151] ,

[0152] Then the potential energy function Part 1 :

[0153] 。

[0154] Regarding the end effector and tooling components, consider that the robot's end effector is positioned at...

[0155] ,

[0156] Then the potential energy function Part 1 :

[0157] .

[0158] In summary, the final gravitational potential energy function for: .

[0159] Taking its partial differential with respect to the generalized vector q, we get:

[0160] .

[0161] The derivation process of the above three control components is explained below:

[0162] The derivation objective is to design a control signal (general control command). This allows the robot joints (i.e., each motor) to accurately track the desired trajectory, while ensuring that all signals are bounded and that the position error is strictly limited within a preset safety boundary.

[0163] For simplicity, define Represents the position vector (i.e., the current actual position value). Let the velocity vector (i.e., the current actual velocity value) be represented; then the dynamic equations of the robot system simplify to:

[0164] ,

[0165] .

[0166] First, define the position tracking error. and speed tracking error The design goal is to make and Approaching 0, and the current actual position value , The upper limit of the motor's position constraint; where It is the virtual control law (i.e., the desired speed value) that is about to be designed.

[0167] Then, the derivation is performed based on the reverse reasoning method:

[0168] First, design virtual control laws. ,consider dynamics ,because Substituting, we get:

[0169] ,

[0170] Choosing an integral barrier: Lyapunov function :

[0171] ,

[0172] The reason for choosing the integral barrier Lyapunov function instead of the ordinary Lyapunov function here is that this function establishes a safety boundary. .when When approaching the boundary, It tends to infinity, thus forcing the controller to take action.

[0173] right Differentiating, we get:

[0174] ,

[0175] in, , yes The same applies to the following components.

[0176] In order to Negative definiteness, based on the above formula, includes as well as Therefore, a virtual control law is designed. To offset the The term is introduced, and a negative definite term is used to stabilize it. ,Right now,

[0177] ,in, Let be the feedback gain coefficient of the i-th motor in the virtual control law;

[0178] The design Substitute get:

[0179] ,

[0180] The first term is negative definite, but the second term includes a new error. This will be addressed in the next step.

[0181] Second, design the true control rate (total control force command). ),consider dynamics = ;

[0182] Constructing composite Lyapunov functions :

[0183] ,

[0184] in, This represents the energy of the speed error;

[0185] right Differentiating, we get:

[0186] ,

[0187] Based on the above formula, it consists of the following three parts: a negative definite term, a cross term, and a term containing... The last item.

[0188] In order to Negative fixed value, design overall control force command To accomplish three tasks: first, to cancel out the cross terms; second, to introduce a new negative fixed term. To stabilize Third, it cancels out the known nonlinear forces in the system model. ;

[0189] Therefore, the overall control command The expression is:

[0190] ,

[0191] iBLF constraint feedback term ( The first term (from the first step of the design) comes from the Lyapunov function, which represents the integration barrier. derivative The term in the design process involves cross-references. To stabilize the system, this term, introduced in the first step of the design, must be offset. Its existence is to rigorously ensure that the safety constraints set in the first step are maintained.

[0192] Velocity error damping term ( The second item is for stabilizing speed tracking error. The negative feedback term is actively introduced. Without it, the system might only reach critical stability or oscillate. Its purpose is to dissipate energy, suppress oscillations, and ensure that the system converges quickly and smoothly.

[0193] Model feedforward compensation term ( The third term (in the equation) comes directly from the system's dynamic equations, in the derivation This naturally arises. To stabilize the system, it must be counteracted by an equal term. Its existence is to counteract the robot's own physical properties (inertia, coupling, gravity).

[0194] Construct the following theorem:

[0195] Given the following conditions:

[0196] ; ;

[0197] , Defined as a tiny positive constant, consider the following function:

[0198] ,in, For integration variables;

[0199] Then the function It is a positive definite monotonically decreasing function that is continuously differentiable, and

[0200] .

[0201] The proof of the above theorem is as follows:

[0202] Considering ,Know for Given a positive definite, monotonically decreasing function that is continuously differentiable, then... The lower boundary is:

[0203] .

[0204] for Let the upper boundary be . .

[0205] right Seeking Relativity The partial derivative is:

[0206] It is easy to know Zhengding.

[0207] Then it can be known for Monotonically increasing.

[0208] Therefore, we get:

[0209] .

[0210] In summary, it can be proved that It is a positive definite, monotonically decreasing function that is continuously differentiable and satisfies:

[0211] .

[0212] According to the following lemma: Suppose there exists a Lyapunov function. It is positive definite, continuous and bounded, satisfying ,in and If a function is positive definite, and its first derivative satisfies ,in and If it is a positive constant, then it can be considered as The state vector eventually becomes asymptotically stable and converges to a compact and definite set. It is known that... The first derivative satisfies Then the position tracking error of the robot joint can be determined. It can eventually converge asymptotically to a stable state.

[0213] Construct the following theorem:

[0214] For the overall control command The output of yields the exponential stability of the system, and both convergences are restricted to compact sets. and ,

[0215] ,

[0216] ,in, For function The value at t=0.

[0217] The proof of the above theorem is as follows:

[0218] ,

[0219] Will Substituting the values, we get:

[0220] .

[0221] consider Substituting the upper boundary into the above equation, we get:

[0222] ,

[0223] in, ; , These represent the minimum and maximum eigenvalues ​​of the matrix, respectively.

[0224] In summary, through the proof of the above theorem, the asymptotic stability of the system is proven. Therefore, the position tracking error of the motor can be determined. and speed tracking error It can consistently maintain exponential stability and guarantees convergence within the following range:

[0225] ,

[0226] .

[0227] Simulation verification:

[0228] The simulation system was built using V-REP and Matlab. V-REP was responsible for robot dynamics modeling and motion simulation, while Matlab handled control input calculations and output. Joint trajectory tracking control, as part of robot dynamics control, is generally at the lower level in robot control applications. It involves the basic position and velocity tracking of each joint motor and is fundamental for achieving master-slave control and automated paths. The robot parameter settings are shown in Table 1, and the control system parameter settings are shown in Table 2. Considering that the robot control system is essentially a signal system, a sine function curve was used as the verification index.

[0229] The robot parameters are shown in Table 1 below:

[0230]

[0231] Table 1

[0232] The control parameters are shown in Table 2 below:

[0233]

[0234] Table 2

[0235] The speed controller parameters are the feedback gain coefficients in the virtual control law mentioned above. The model controller parameters are the damping gain parameters mentioned above.

[0236] The following position reference trajectories are set for the five joints (motors) of the robot, where t is the time variable:

[0237] ,

[0238] The velocity reference trajectory of the joint is obtained as follows:

[0239] .

[0240] Set the step size of the control system to In order to compare the initial positions of the robot's five joints, The test was repeated 10 times within the range, and the position and velocity tracking results of 5 joints were finally obtained. Figures 4a to 4e They were shown respectively to The trajectory effect of the joints (corresponding to motors 11, 12, 21, 22, and 31, where the displacement of the motors is used to represent the joints) is shown. The red surface represents the actual position and velocity results of each joint from multiple tests, and the red curve represents the average actual position and velocity of each joint from multiple tests. The blue line represents the reference trajectory. To more clearly illustrate the convergence error range, a magnified view of the final convergence error is inserted into each error graph. As can be seen from the figures, the control method provided in this disclosure can achieve exponential convergence of position and velocity errors, considering the parameters... for It can be seen that the controller can successfully limit the positional error of all five joints. Inside.

[0241] In one embodiment of this disclosure, the first control component is used... Second control component and the third control component Receive the master control command ,include:

[0242] Based on the first control component Second control component and the third control component Any combination of the following will produce the master control command. :

[0243] Combination 1: ;

[0244] Combination 2: ;

[0245] Combination 3: .

[0246] In this disclosed method, during the generation of the overall control command, Combination 1 achieves the synergistic effect of error constraint, damping compensation, and dynamic feedforward by superimposing three control components, suitable for high-precision trajectory tracking scenarios; Combination 2 simplifies the control structure by omitting the dynamic feedforward term, suitable for operating conditions with small load disturbances; Combination 3 strengthens error constraint and dynamic compensation by omitting the damping term, suitable for rigid contact scenarios. The control mode can be switched in real time according to the actual operating conditions through controller parameter configuration.

[0247] Through the above technical solution, this application realizes multi-mode adaptive control, which can dynamically select the optimal control structure according to the motion state of the surgical instruments while ensuring that the position error does not exceed the safety boundary. This avoids the limitations of a single control strategy and reduces the computational load caused by complex dynamic compensation, providing differentiated control guarantees for different operation stages in ophthalmic microsurgery.

[0248] In one embodiment of this disclosure, a general control command is output to each motor drive element. Same or different.

[0249] In this disclosure, the same or different general control commands refer to the selective adoption of unified or differentiated control strategies based on the dynamic characteristics or task requirements of different motor drive components. Specifically, this can be achieved using a dynamic allocation algorithm, such as adjusting command parameters according to the real-time load status or position error range of each motor. This feature allows the system to adapt to the mechanical characteristics of different joint modules, avoiding overload or tracking error accumulation caused by a single control mode. When the general control commands are different, control parameters can be set separately for the axial feed motion characteristics of the fifth motor, while the first four motors maintain synchronous control according to parallel drive requirements.

[0250] Specifically, when two motors in the same joint module need to move in coordination, their drive elements receive the same overall control command, ensuring precise coupling between the translational and rotational degrees of freedom of the rigid linkage mechanism. For example, when the two motors in the first joint module drive the linkage to translate, they use the same command to ensure consistency in the plane of motion. Motor drive elements in different joint modules use different combinations of overall control commands based on the differences in their respective dynamic models. For example, when the fifth motor in the third joint module drives the surgical tool axially, its command combination can be selected to include only the first and third control components to eliminate nonlinear interference caused by the rotational degree of freedom.

[0251] Through the above technical solution, this application achieves refined control of a multi-motor system. While ensuring the stability of the remote motion center, it eliminates dynamic interference between different joint modules through differentiated command configuration, avoiding the problem of error superposition caused by unified control. This method is particularly suitable for the coordinated control of axial micro-feeding and rotational motion of instruments in ophthalmic surgery, ensuring that the linear motion accuracy of the fifth motor is not affected by the coupling of the rotational degrees of freedom of other joints.

[0252] In one embodiment of this disclosure, a general control command is output to the motor drive elements of two motors in the same joint module. The same, and different joint modules, have the same total control command input to the motor drive elements of the two motors. different.

[0253] In this disclosure, the two motors in the same joint module refer to two parallel motors in each joint module, which convert translational degrees of freedom into translational and rotational degrees of freedom through a rigid linkage mechanism. Specifically, this can be achieved using a dual-motor synchronous drive mechanism, with unified control commands ensuring that the motion trajectories of the two motors are completely consistent. The two motors in different joint modules refer to drive units belonging to different series modules, which can be achieved using an independent control strategy, adjusting the combination of translational and rotational degrees of freedom of each module through differentiated commands.

[0254] Specifically, in the first and second joint modules, the overall control command for the two parallel motors is set to the same value, ensuring that the rigid linkage mechanism maintains balanced force during movement and preventing deformation due to asynchronous drives. The fifth motor in the third joint module receives control commands different from those in the other modules, enabling independent adjustment of the surgical tool's feed along the axis.

[0255] In this disclosure, unless otherwise specified, Ai represents the i-th component of vector A, where A is any vector.

[0256] Through the above technical solution, this application effectively solves the synchronization accuracy problem of dual-motor driven joints, reduces the deformation risk of linkage mechanism caused by asymmetric driving force, and realizes independent control of the motion mode of each joint through modular command allocation, avoiding the dynamic coupling effect when multi-module linkage control, thereby improving the overall motion accuracy and stability of the system.

[0257] This disclosure also provides a serial-parallel robot system with a three-dimensional adjustable remote motion center. The serial-parallel robot system includes three joint modules connected in series and arranged perpendicularly to each other. The three joint modules include a first joint module, a second joint module, and a third joint module. The first and second joint modules have the same structure. Each joint module includes two motors arranged in parallel and a rigid linkage mechanism. The rigid linkage mechanism is used to output the translational degrees of freedom of the two motors as the translational and rotational degrees of freedom of the joint module. The third joint module includes a fifth motor and a surgical tool. The fifth motor is used to adjust the feed amount of the surgical tool along the tool axis.

[0258] The serial-parallel robot system also includes a controller configured to perform the following control method:

[0259] S1: Obtain the desired pose of the surgical instrument tip in the current cycle;

[0260] S2: Based on the inverse kinematics of the serial-parallel robot system, the desired pose is calculated as the desired position value of each motor drive element in the current cycle. And based on the desired position value By comparing the expected position value with the historical cycle values, the expected velocity value of the current cycle is determined. and expected acceleration value ;

[0261] S3: Real-time acquisition of the current actual position value of each motor drive component. and the current actual speed value ;

[0262] S4: Calculate the position tracking error for the current cycle. and speed tracking error ;

[0263] S5: Based on the integral barrier Lyapunov function, according to the position tracking error... and the preset motor position safety boundary Calculate the first control component The first control component This is used to constrain the position tracking error within the motor position safety boundary;

[0264] S6: Based on the speed tracking error Calculate the second control component The second control component Used to provide system damping;

[0265] S7: Based on the dynamic model of the serial-parallel robot system, according to the desired velocity value... and expected acceleration value Calculate the third control component The third control component Nonlinear dynamic effects used in feedforward compensation systems;

[0266] S8: Based on the first control component Second control component and the third control component Receive the master control command ;

[0267] S9: The overall control command The output is sent to each motor drive component to drive the motor to move.

[0268] For specific technical details of the embodiments disclosed herein, please refer to the above embodiments, which will not be repeated here.

[0269] In one embodiment of this disclosure, the first control component is used... Second control component and the third control component Receive the master control command ,include:

[0270] Based on the first control component Second control component and the third control component Any combination of the following will produce the master control command. :

[0271] Combination 1: ;

[0272] Combination 2: ;

[0273] Combination 3: .

[0274] In one embodiment of this disclosure, a general control command is output to each motor drive element. Same or different.

[0275] In one embodiment of this disclosure, a general control command is output to the motor drive elements of two motors in the same joint module. The same, and different joint modules, have the same total control command input to the motor drive elements of the two motors. different.

[0276] In one embodiment of this disclosure, the first control component The calculation formula is:

[0277]

[0278] in, Let i be the motor position safety boundary for the i-th motor. Let be the upper limit of the position constraint for the i-th motor. This is a preset constant; Let be the position tracking error of the i-th motor; The speed tracking error of the i-th motor; This indicates a pseudo-inverse operation; .

[0279] In one embodiment of this disclosure, the second control component The calculation formula is:

[0280]

[0281] in, This is the damping gain parameter.

[0282] In one embodiment of this disclosure, the third control component The calculation formula is:

[0283]

[0284] in, It is the Coriolis force matrix. It is the gravity term. It is the mass matrix, calculated based on the dynamic model of the series-parallel robot system.

[0285] In one embodiment of this disclosure, the two motors and the fifth motor are micrometer-level precision motors or nanometer-level precision motors.

[0286] In this disclosure, a micrometer-level precision motor refers to a drive device capable of achieving micrometer-level displacement resolution. Specifically, it can be implemented using a piezoelectric ceramic motor or a closed-loop stepper motor, with a repeatability accuracy within ±1 micrometer. A nanometer-level precision motor refers to a drive device capable of achieving nanometer-level displacement resolution. Specifically, it can be implemented using a voice coil motor combined with a high-resolution optical grating ruler feedback system, with a displacement resolution of up to 0.1 nanometers. In serial-parallel robot systems, using such high-precision motors ensures sufficient resolution for the translational and rotational outputs of joint modules, thereby precisely controlling the spatial position of the remote motion center point.

[0287] Specifically, in ophthalmic microsurgery, surgical tools require precise manipulation of the cornea or retina with micrometer-level accuracy. When using a micrometer-level precision motor, the step size of the fifth motor driving the surgical tool along the axis can be controlled within 5 micrometers, meeting the precision requirements of surgeries such as phacoemulsification for cataracts. When performing ultra-precise operations such as retinal vascular anastomosis, a nanometer-level precision motor enables the tool tip displacement resolution to reach the 100-nanometer level, avoiding tissue damage caused by overshoot. Simultaneously, when the two parallel motors of the first and second joint modules convert linear motion into rotational degrees of freedom through a rigid linkage mechanism, the micrometer-level motion error, even after being amplified by the mechanism, still maintains the end-effector posture error within a safe threshold.

[0288] In one embodiment of this disclosure, the robotic system is used for ophthalmic surgery, the surgical tool is an ophthalmic microsurgical instrument, and the remote motion center point is located within the eyeball region.

[0289] In this disclosure, ophthalmic microsurgical instruments refer to surgical tools with minimally invasive characteristics. Specifically, they can be instruments with microscopic gripping, cutting, or suction functions, and their structural dimensions are adapted to the internal operating space of the eyeball. The remote motion center point being located within the eyeball region means that, through robot configuration and control algorithms, the virtual center of the tool's rotation is constrained within the anatomical structure of the eyeball. This can be achieved by combining preoperative medical image registration with real-time intraoperative kinematic calculations, ensuring that the instrument's trajectory always revolves around a specific area inside the eyeball.

[0290] Specifically, this robotic system achieves three-dimensional position adjustment of the remote motion center while maintaining high rigidity through a series-parallel configuration of three joint modules. The rigid linkage mechanism of the first and second joint modules converts the translational degrees of freedom of the two motors into translational and rotational degrees of freedom, while the fifth motor of the third joint module controls the instrument's axial feed. In ophthalmic surgery scenarios, the controller calculates the instrument's end-effector pose based on inverse kinematics and generates control commands using an integral-limited Lyapunov function, causing the instrument tip to move around a pre-defined area inside the eyeball. For example, in vitrectomy, the instrument adjusts the insertion depth through the axial feed of the third joint module, while the first two joint modules work together to adjust the rotation angle of the instrument around the intraocular hemorrhage point, ensuring that the cutting operation does not damage the surrounding retinal tissue.

[0291] This application addresses the problem of insufficient matching between the movement trajectory of instruments and the anatomical structure of the eyeball in ophthalmic surgery. Through a dynamically adjustable remote motion center constraint mechanism, it effectively reduces the risk of accidental collision between instruments and fragile intraocular tissues while ensuring the precision of minimally invasive operations. It is especially suitable for complex fundus surgery scenarios that require multi-angle operation.

[0292] This disclosure also discloses an electronic device. Figure 5 A structural block diagram of an electronic device according to an embodiment of the present disclosure is shown.

[0293] like Figure 5 As shown, the electronic device includes a memory and a processor, wherein the memory is used to store one or more computer instructions, wherein the one or more computer instructions are executed by the processor to implement the method according to embodiments of the present disclosure.

[0294] The control method for the serial and parallel robot system with a three-dimensional adjustable remote motion center includes:

[0295] S1: Obtain the desired pose of the surgical instrument tip in the current cycle;

[0296] S2: Based on the inverse kinematics of the serial-parallel robot system, the desired pose is calculated as the desired position value of each motor drive element in the current cycle. And based on the desired position value By comparing the expected position value with the historical cycle values, the expected velocity value of the current cycle is determined. and expected acceleration value ;

[0297] S3: Real-time acquisition of the current actual position value of each motor drive component. and the current actual speed value ;

[0298] S4: Calculate the position tracking error for the current cycle. and speed tracking error ;

[0299] S5: Based on the integral barrier Lyapunov function, according to the position tracking error... and the preset motor position safety boundary Calculate the first control component The first control component This is used to constrain the position tracking error within the motor position safety boundary;

[0300] S6: Based on the speed tracking error Calculate the second control component The second control component Used to provide system damping;

[0301] S7: Based on the dynamic model of the serial-parallel robot system, according to the desired velocity value... and expected acceleration value Calculate the third control component The third control component Nonlinear dynamic effects used in feedforward compensation systems;

[0302] S8: Based on the first control component Second control component and the third control component Receive the master control command ;

[0303] S9: The overall control command The output is sent to each motor drive component to drive the motor to move.

[0304] In one embodiment of this disclosure, the first control component is used... Second control component and the third control component Receive the master control command ,include:

[0305] Based on the first control component Second control component and the third control component Any combination of the following will produce the master control command. :

[0306] Combination 1: ;

[0307] Combination 2: ;

[0308] Combination 3: .

[0309] In one embodiment of this disclosure, a general control command is output to each motor drive element. Same or different.

[0310] In one embodiment of this disclosure, a general control command is output to the motor drive elements of two motors in the same joint module. The same, and different joint modules, have the same total control command input to the motor drive elements of the two motors. different.

[0311] In one embodiment of this disclosure, the first control component The calculation formula is:

[0312]

[0313] in, Let i be the motor position safety boundary for the i-th motor. Let be the upper limit of the position constraint for the i-th motor. This is a preset constant; Let be the position tracking error of the i-th motor; The speed tracking error of the i-th motor; This indicates a pseudo-inverse operation; .

[0314] In one embodiment of this disclosure, the second control component The calculation formula is:

[0315]

[0316] in, This is the damping gain parameter.

[0317] In one embodiment of this disclosure, the third control component The calculation formula is:

[0318]

[0319] in, It is the Coriolis force matrix. It is the gravity term. It is the mass matrix, calculated based on the dynamic model of the series-parallel robot system.

[0320] Figure 6 A schematic diagram of the structure of a computer system suitable for implementing the method according to embodiments of the present disclosure is shown.

[0321] like Figure 6As shown, the computer system includes a processing unit that can execute various methods described above based on a program stored in a read-only memory (ROM) or a program loaded from a storage portion into a random access memory (RAM). The RAM also stores various programs and data required for the operation of the computer system. The processing unit, ROM, and RAM are interconnected via a bus. Input / output (I / O) interfaces are also connected to the bus.

[0322] The following components are connected to the I / O interface: input sections including keyboards, mice, etc.; output sections including cathode ray tubes (CRTs), liquid crystal displays (LCDs), and speakers; storage sections including hard disks; and communication sections including network interface cards such as LAN cards and modems. The communication section performs communication processes via a network such as the Internet. Drives are also connected to the I / O interface as needed. Removable media, such as disks, optical disks, magneto-optical disks, semiconductor memories, etc., are installed on the drive as needed so that computer programs read from them can be installed into the storage section as required. The processing unit can be implemented as a CPU, GPU, TPU, FPGA, NPU, etc.

[0323] In particular, according to embodiments of this disclosure, the methods described above can be implemented as computer software programs. For example, embodiments of this disclosure include a computer program product comprising a computer program tangibly embodied on a machine-readable medium, the computer program containing program code for performing the methods described above. In such embodiments, the computer program can be downloaded and installed from a network via a communication component, and / or installed from a removable medium.

[0324] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0325] The units or modules described in the embodiments of this disclosure can be implemented in software or programmable hardware. The described units or modules can also be located in a processor, and the names of these units or modules do not necessarily constitute a limitation on the unit or module itself.

[0326] In another aspect, this disclosure also provides a computer-readable storage medium, which may be a computer-readable storage medium included in the electronic device or computer system described above; or it may be a standalone computer-readable storage medium not assembled into a device. The computer-readable storage medium stores one or more programs, which are used by one or more processors to perform the methods described in this disclosure.

[0327] The above description is merely a preferred embodiment of this disclosure and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this disclosure is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features disclosed in this disclosure that have similar functions.

Claims

1. A control method for a serial-parallel robot system with a three-dimensional adjustable remote motion center, characterized in that, The serial-parallel robot system includes three joint modules connected in series and arranged perpendicularly to each other. The three joint modules include a first joint module, a second joint module, and a third joint module. The first and second joint modules have identical structures. Each joint module includes two parallel motors and a rigid linkage mechanism. The rigid linkage mechanism is used to output the translational degrees of freedom of each of the two motors as the translational and rotational degrees of freedom of the joint module. The third joint module includes a fifth motor and surgical tools. The control method includes: S1: Obtain the desired pose of the surgical instrument tip in the current cycle; S2: Based on the inverse kinematics of the serial-parallel robot system, the desired pose is calculated as the desired position value of each motor drive element in the current cycle. And based on the desired position value By comparing the expected position value with the historical cycle values, the expected velocity value of the current cycle is determined. and expected acceleration value ; S3: Real-time acquisition of the current actual position value of each motor drive component. and the current actual speed value ; S4: Calculate the position tracking error for the current cycle. and speed tracking error ; S5: Based on the integral barrier Lyapunov function, according to the position tracking error... and the preset motor position safety boundary Calculate the first control component ; S6: Based on the speed tracking error Calculate the second control component ; S7: Based on the dynamic model of the serial-parallel robot system, according to the desired acceleration value Calculate the third control component ; S8: Based on the first control component Second control component and the third control component Receive the master control command ; S9: The overall control command The output is sent to each motor drive component to drive the motor to move.

2. The control method according to claim 1, characterized in that, Based on the first control component Second control component and the third control component Receive the master control command ,include: Based on the first control component Second control component and the third control component Any combination of the following will produce the master control command. : Combination 1: Combination 2: ; Combination 3: .

3. The control method according to claim 2, characterized in that, The overall control command output to each motor drive element Same or different.

4. The control method according to claim 3, characterized in that, The overall control command output to the motor drive elements of the two motors in the same joint module The same, and different joint modules, have the same total control command input to the motor drive elements of the two motors. different.

5. The control method according to claim 2, characterized in that, The first control component The calculation formula is: in, Let i be the motor position safety boundary for the i-th motor. Let be the upper limit of the position constraint for the i-th motor. This is a preset constant; Let be the position tracking error of the i-th motor; The speed tracking error of the i-th motor; This represents the current actual position value of the i-th motor; This indicates a pseudo-inverse operation; .

6. The control method according to claim 2, characterized in that, Second control component The calculation formula is: in, This is the damping gain parameter.

7. The control method according to claim 2, characterized in that, The third control component The calculation formula is: in, It is the Coriolis force matrix. It is the gravity term. It is the mass matrix, calculated based on the dynamic model of the series-parallel robot system.

8. A serial-parallel robot system with a three-dimensional adjustable remote motion center, characterized in that, The serial-parallel robot system includes three joint modules connected in series and arranged perpendicularly to each other. The three joint modules include a first joint module, a second joint module, and a third joint module. The first and second joint modules have the same structure. Each joint module includes two motors arranged in parallel and a rigid linkage mechanism. The rigid linkage mechanism is used to output the translational degrees of freedom of each of the two motors as the translational and rotational degrees of freedom of the joint module. The third joint module includes a fifth motor and a surgical tool. The fifth motor is used to adjust the feed amount of the surgical tool along the tool axis. The serial-parallel robot system further includes a controller configured to perform the control method as described in any one of claims 1-7.

9. The serial-parallel robot system according to claim 8, characterized in that, The two motors and the fifth motor are either micrometer-level precision motors or nanometer-level precision motors.

10. The serial-parallel robot system according to claim 8, characterized in that, The serial-parallel robot system is used for ophthalmic surgery, the surgical tools are ophthalmic microscopic instruments, and the remote motion center point is located within the eyeball area.

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