A marine medical operation platform and its self-balancing control method

Abstract

The present invention provides a marine medical operation platform and its self-balancing control method. The marine medical operation platform includes an operation table and a stabilization platform. The stabilization platform includes a parallel mechanism, a lower drag pedal, an inertial navigation unit, an encoder, and a control unit. The parallel mechanism includes an upper platform, a lower platform, and an actuator. The operation table and the lower drag pedal are respectively fixedly connected to the upper platform. The lower platform is fixedly installed on the deck of the hull, and the actuator can drive the upper platform to move. The inertial navigation unit is installed on the lower platform and is used to obtain the vibration information of the lower platform. The encoder is installed on the actuator and is used to detect the motion information of the actuator. The control unit actively controls the actuator to act based on the vibration information of the lower platform and the motion information of the actuator, so that the upper platform remains stable during the ship's voyage. The present invention can achieve all-round and high-efficiency vibration reduction and overcome the influence of sea wave impact to realize offshore surgery.

Description

Technical Field

[0001] The present invention relates to the field of marine medical equipment, and particularly to a marine medical operation platform and its self-balancing control method. Background Art

[0002] On the rough sea surface, various ships such as warships, medical ships, and transport ships will be continuously impacted by seawater in different directions, causing continuous large-amplitude low-frequency rocking of the ship. On relatively small warships such as destroyers and frigates, the rolling, pitching, yawing, swaying, heaving, and surging of the ship will be more obvious. These rockings seriously affect the accuracy of performing operations on the ship, and are very likely to further aggravate the injuries of the wounded.

[0003] Traditional ship anti-rolling devices, such as anti-rolling water tanks, anti-rolling rudders, anti-rolling gyros, anti-rolling fins, anti-rolling weights, etc., are large in volume, heavy in weight, high in power consumption, and high in cost. They are mainly used for anti-rolling in some dimensions of the ship (such as rolling or pitching), and cannot achieve anti-rolling in all 6 dimensions at the same time. Moreover, the ship still has a large swing after being processed by the anti-rolling device, and the problem of rocking cannot be completely solved.

[0004] According to the literature [1], traditional shipboard operating tables basically still follow the fixed land-based comprehensive operating tables. For the bumps caused by sea waves, only the installation fixators of the operating table are used to reduce the impact of vibration on various medical instruments. At the same time, it is required that medical staff perform operations in the "low position, sitting position, three fixations, and synchronous movement" to relieve the instability caused by the ship's rocking and reduce surgical errors. However, these measures can only meet the minimum safety requirements for performing surgical operations, and in the face of relatively harsh wave surface environments, surgical operations cannot be normally carried out at present.

[0005] [1] Wang Xun, Shen Junliang, Xia Zhifang, etc. Development of a shipborne comprehensive operating table [J]. Journal of Navy Medicine, 2005, 6(26): 139-141. Summary of the Invention

[0006] The present invention provides a marine medical operation platform and its self-balancing control method for at least some deficiencies of the prior art.

[0007] The technical solution provided by the present invention is as follows:

[0008] A marine medical operation platform includes an operating table and a stable platform located below the operating table;

[0009] The stable platform includes a parallel mechanism, a lower drag pedal, an inertial navigation unit, an encoder, and a control unit;

[0010] The parallel mechanism includes an upper platform, a lower platform, and an actuator connected between the upper platform and the lower platform; the upper platform is fixedly connected to the operating table, the lower platform is fixedly installed on the deck of the hull, and the actuator can drive the upper platform; the actuator includes a plurality of independent kinematic chains, and each kinematic chain uses a servo cylinder for telescopic movement;

[0011] The lower drag pedal is fixedly connected to the upper platform;

[0012] The inertial navigation unit is fixedly installed on the lower platform for obtaining the vibration information of the lower platform;

[0013] The encoder is installed on the actuator for detecting the motion information of the actuator;

[0014] The control unit is electrically connected to the encoder and the inertial navigation unit, and actively controls the action of the actuator based on the vibration information of the lower platform, the motion information of the actuator, and the kinematic relationship between the upper platform and the lower platform, so as to keep the upper platform stable during the ship's navigation.

[0015] In some embodiments, the operating table includes an operating table top;

[0016] The operating table top is divided into four parts, wherein the first part and the second part are connected by a pillow shaft, the second part and the third part are connected by a waist shaft, and the third part and the fourth part are connected by a leg shaft.

[0017] In some embodiments, the operating table further includes a lifting mechanism, and the lifting mechanism is located below the operating table top and embedded in the upper platform.

[0018] In some embodiments, the parallel mechanism adopts a 6-degree-of-freedom stewart configuration.

[0019] In some embodiments, limit switches are respectively installed at the stroke ends of the servo cylinders.

[0020] In some embodiments, variable stiffness springs are nested outside the servo cylinders, and / or anti-collision springs or anti-collision pads are added at the stroke ends of the servo cylinders.

[0021] In some embodiments, the kinematic chain includes a servo hydraulic cylinder and a hydraulic locking circuit, the hydraulic locking circuit is connected to the oil inlet and outlet of the servo hydraulic cylinder, and the hydraulic locking circuit uses an overflow valve, a three-position four-way directional control valve, and two pilot-operated check valves to achieve self-locking of the servo hydraulic cylinder.

[0022] In some embodiments, a number of safety columns are installed around the parallel mechanism. The safety columns are located at the boundary points of the task space of the parallel robot. The inside of each safety column is a rigid column body, and the outside is wrapped with an elastic material. Each safety column is connected to the upper platform of the parallel mechanism through a passive chain. The passive chain has more than six degrees of freedom and adopts a UPS or SPS configuration.

[0023] The present invention also provides a self-balancing control method, which is applied to the aforementioned marine medical operation platform, and includes: obtaining the pose information of the lower platform of the marine medical operation platform at the current moment; obtaining the relative motion information of the upper platform of the marine medical operation platform relative to the lower platform at the current moment; determining the relative motion information that the upper platform needs to correct according to the pose information of the lower platform at the current moment and the relative motion information of the upper platform at the current moment; determining the desired motion information of the actuator according to the relative motion information that the upper platform needs to correct; and controlling the actuator to drive the upper platform to move according to the desired motion information.

[0024] In some embodiments, the determining the relative motion information that the upper platform needs to correct according to the pose information of the lower platform at the current moment and the relative motion information of the upper platform at the current moment includes:

[0025] determining the control rate of the relative motion of the upper platform relative to the lower platform according to the pose information of the lower platform at the current moment and the relative motion information of the upper platform at the current moment;

[0026] obtaining the relative motion information that the upper platform needs to correct through numerical integration according to the control rate of the relative motion of the upper platform relative to the lower platform.

[0027] Compared with the prior art, the marine medical operation platform and its self-balancing control method provided by the present invention have at least one of the following beneficial effects:

[0028] 1. The bottom of the marine medical operation platform of the present invention is a multi-dimensional parallel robot stable platform, which can actively reduce the influence of sea wave impact from multiple dimensions, improve the stability of the operating table during ship navigation; by introducing a lower drag pedal fixedly connected to the upper platform to carry medical staff, the mutual movement between medical staff and the wounded and sick is avoided; enabling medical staff to perform operations with the feeling of a land hospital, improving the success rate and efficiency of maritime operations.

[0029] 2. The marine medical operation platform of the present invention is a multi-degree-of-freedom series-parallel hybrid robot, which consists of two parts: the bottom is a multi-dimensional parallel robot stable platform, and the top is a multi-axis series operating table, which can adjust the posture of the wounded and sick according to the surgical requirements.

[0030] 3. The marine medical operation platform of the present invention adopts an integrated design, and reduces the height and volume of the operation platform through embedded design and retractable structure.

[0031] 4. The present invention improves the safety of the marine medical operation platform by adding hardware safety measures, structural safety measures and software safety measures. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The above characteristics, technical features, advantages and implementation manners of a marine medical operation platform and its self-balancing control method will be further described below in a clear and understandable manner in combination with the drawings and preferred embodiments.

[0033] Figure 1 is a schematic structural diagram of an embodiment of the marine medical operation platform of the present invention;

[0034] Figure 2 is a flowchart of an embodiment of the self-balancing control method of the marine medical operation platform of the present invention;

[0035] Figure 3 is a schematic diagram of a general parallel robot;

[0036] Figure 4 and Figure 5 are respectively a schematic external view and a schematic structural diagram of another embodiment of the marine medical operation platform of the present invention;

[0037] Figure 6 and Figure 7 are respectively a working flowchart and a control flowchart of another embodiment of the self-balancing control method of the marine medical operation platform of the present invention;

[0038] Figure 8 is a vibration reduction effect diagram of the marine medical operation platform of the present invention in the directions of surge, sway and heave;

[0039] Figure 9 is a vibration reduction effect diagram of the marine medical operation platform of the present invention in the directions of roll, pitch and yaw;

[0040] Figure 10 is a schematic structural diagram of a variable stiffness spring nested in a servo electric cylinder or a hydraulic cylinder;

[0041] Figure 11 is a schematic structural diagram of an anti-collision spring or an anti-collision pad added at the stroke end of a servo electric cylinder or a hydraulic cylinder;

[0042] Figure 12 is a schematic structural diagram of adding a hydraulic locking circuit to a servo hydraulic cylinder;

[0043] Figure 13It is a schematic structural diagram of adding a protection mechanism in the task space of a parallel mechanism. Specific implementation manner

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the specific implementation manners of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings, and other implementation manners can also be obtained.

[0045] To make the drawings concise, only the parts related to the present invention are schematically shown in each drawing, and they do not represent their actual structures as products. In addition, to make the drawings concise and easy to understand, in some drawings, components with the same structure or function are only schematically drawn one of them, or only one of them is marked. In this article, "one" not only means "only this one", but also means "more than one" situation.

[0046] An embodiment of the present invention, as Figure 1 shown, a marine medical operation platform includes an operation table 10 and a stable platform 20 located below the operation table.

[0047] The operation table 10 includes an operation table surface 11. The stable platform 20 includes a parallel mechanism, a lower drag pedal 21, an inertial navigation unit 22, an encoder, and a control unit (not shown).

[0048] The parallel mechanism, also known as a parallel robot, is defined as a closed-loop mechanism in which a moving platform and a fixed platform are connected by at least two independent kinematic chains, the mechanism has two or more degrees of freedom, and is driven in a parallel manner.

[0049] The parallel mechanism includes an upper platform 211 (i.e., the moving platform), a lower platform 213 (i.e., the fixed platform), and an actuator 212 connected between the upper platform and the lower platform. The upper platform 211 is fixedly connected to the operation table 10, the lower platform 213 is fixedly installed on the deck of the ship's hull, and the actuator 212 can drive the upper platform 211 to move relative to the lower platform 213. The actuator includes multiple independent kinematic chains, and each kinematic chain can use a servo cylinder for telescopic movement. The servo cylinder includes a servo electric cylinder or a servo hydraulic cylinder.

[0050] An encoder is installed on each kinematic chain. The encoder can measure the telescopic displacement of the kinematic chain where it is located, and the telescopic speed can be further obtained based on the telescopic displacement. In this way, the motion information of the actuator can be obtained through the encoder. According to the requirements of the vibration damping dimension, the parallel mechanism can adopt a variety of different configurations. If it is desired to reduce the influence of roll, pitch, yaw, sway, surge, and heave simultaneously, a parallel robot with 6 or more degrees of freedom should be used. The Stewart configuration is preferably used to achieve all-round vibration damping in 6 dimensions.

[0051] The lower drag pedal 21 is fixedly connected to the upper platform 211. The lower drag pedal is used to carry medical staff, and the operating table carries the wounded and sick. By fixedly connecting the operating table and the lower drag pedal to the upper platform respectively, the relative movement between the patients and medical staff is avoided.

[0052] The inertial navigation unit 22 is fixedly installed on the lower platform 213 and is used to obtain the vibration information of the lower platform. The inertial navigation unit includes a three-axis accelerometer, a three-axis gyroscope, and a three-axis magnetometer, and can detect the vibration information of the installation carrier of the inertial navigation unit. The vibration information includes the three-axis acceleration in the system and the three-axis angular velocity in the system. Through further calculation and processing (such as integration), the real-time position, speed, and angle information of the installation carrier can be obtained. In some embodiments, the inertial navigation unit further includes a GPS for obtaining GPS position information to enhance the sensing accuracy.

[0053] The control unit is electrically connected to the encoder and the inertial navigation unit, and actively controls the actuator to act based on the vibration information of the lower platform, the motion information of the actuator, and the kinematic relationship between the upper platform and the lower platform, so that the upper platform remains stable during the ship's voyage.

[0054] In this embodiment, the multi-degree-of-freedom balance function is realized by adopting a parallel robot structure at the bottom, the shaking of the upper platform during the ship's voyage is reduced, and the stability of the operating table fixed above the upper platform is improved; by setting a lower drag pedal fixedly connected to the upper platform, the relative movement between medical staff and the wounded and sick is ensured to be zero; the all-round vibration damping in 6 dimensions is realized by adopting a parallel mechanism with the Stewart configuration. The shipborne medical operating platform provided in this embodiment can actively offset the influence of sea wave impacts, enable medical staff to perform operations with the same feeling as in a land hospital, improve the success rate and efficiency of sea surgeries, and enable the ship to have the ability to perform complex and delicate surgeries.

[0055] In one embodiment, the operating table surface is divided into four parts, where the first part and the second part are connected by a pillow shaft, the second part and the third part are connected by a waist shaft, and the third part and the fourth part are connected by a leg shaft. In this way, the function of dynamically adjusting the posture of the operating bed can be realized.

[0056] On the basis described above, in some embodiments, a lifting mechanism is further provided below the operating tabletop. The lifting mechanism is embedded in the upper platform, and the height of the operating bed can be adjusted through the lifting mechanism. Through the embedded design and the retractable structure, the volume of the operating platform is greatly reduced.

[0057] Considering the high safety requirements of the operating platform, corresponding safety protection measures need to be taken to avoid safety problems such as the platform exceeding the normal working range or even collapsing due to failures. Therefore, hardware safety measures and / or structural safety measures are added to the above-mentioned marine medical operating platform.

[0058] The hardware safety measures include: installing limit switches at both ends of the stroke on both sides of the servo cylinder. When the system detects that the limit switch is triggered, the system operation is stopped to prevent the servo cylinder from exceeding the working limit.

[0059] The structural safety measures can be further divided into joint space safety measures and task space safety measures.

[0060] (1) Joint space safety measures

[0061] Include:

[0062] A. Nest a variable stiffness spring in the servo cylinder

[0063] As Figure 10 shown, a variable stiffness spring is nested outside each servo electric cylinder or servo hydraulic cylinder of the parallel robot. The stiffness of this spring is relatively small near the equilibrium position, and when it is stretched or compressed, the stiffness will increase rapidly. Therefore, when the servo electric cylinder or servo hydraulic cylinder runs near the lowest or highest point, the variable stiffness spring will generate a large restoring force, greatly reducing the possibility of the servo electric cylinder or servo hydraulic cylinder running outside the normal working range.

[0064] B. Add anti-collision springs or anti-collision pads at the end of the stroke of the servo cylinder

[0065] As Figure 11 shown, add anti-collision springs or anti-collision pads at the end of the stroke of each servo electric cylinder or servo hydraulic cylinder of the parallel robot. When the servo electric cylinder or servo hydraulic cylinder runs to the lowest or highest point, the anti-collision springs or anti-collision pads will generate a large resistance to prevent the electric cylinder or hydraulic cylinder from breaking through the stroke.

[0066] C. Add a hydraulic locking circuit to the servo hydraulic cylinder

[0067] If the actuator of the parallel robot is a servo hydraulic cylinder, a hydraulic locking circuit can be used to achieve self-locking of the servo hydraulic cylinder.

[0068] As Figure 12As shown in the figure, the hydraulic locking circuit is connected to the oil inlet and outlet of the servo hydraulic cylinder. The hydraulic locking circuit includes an overflow valve, a three-position four-way directional control valve, and two pilot-operated check valves; the hydraulic power source (hydraulic pump) is connected to the overflow valve and the three-position four-way directional control valve; the three-position four-way directional control valve is respectively connected to the two pilot-operated check valves; the control oil ports of the two pilot-operated check valves are respectively connected to the oil inlet end of another pilot-operated check valve, that is, the control end X1 of the first pilot-operated check valve is connected to the oil inlet end A2 of the second pilot-operated check valve, and the control end X2 of the second pilot-operated check valve is connected to the oil inlet end A1 of the first pilot-operated check valve.

[0069] Only when there is pressure output at the oil inlet end A1 or A2, the control end X1 or X2 will open the pilot-operated check valve to form a working circuit; otherwise, B1 and B2 at the cylinder end are blocked by the check valve to form a closed oil circuit. This device can ensure that when a sudden power failure or other faults occur in the system, the hydraulic cylinder will stay in place and will not move due to other external forces, ensuring that the stable platform composed of parallel robots will not collapse.

[0070] (2) Task space safety measures

[0071] The task space safety measures mainly add a protection mechanism in the task space of the parallel robot. A feasible solution is as Figure 13 shown. Install several safety columns around the parallel robot platform. The safety columns are fixedly installed on the deck of the hull and are located at the boundary points of the task space of the parallel robot. Their function is to prevent the parallel robot from exceeding the working range of the task space and causing phenomena such as tipping.

[0072] The safety columns are made of materials with a rigid inner and flexible outer structure. The inner part is a rigid column, and the outer side is wrapped with elastic materials such as sponge and rubber to avoid rigid collisions.

[0073] In order to produce a better task space protection effect, each safety column and the upper platform of the parallel robot are connected by a passive branch chain. The passive branch chain has more than 6 degrees of freedom and can adopt a UPS or SPS configuration, that is, the passive branch chain body is a sliding pair, and the hinges on both sides are spherical hinges - spherical hinges or spherical hinges - Hooke joints (universal joints). At the same time, anti-collision springs or anti-collision pads are nested on the sliding pair. When the upper surface of the parallel robot approaches the safety column, a large resistance can be generated to prevent it from exceeding the normal working range of the task space.

[0074] According to actual needs, one or more of the above safety protection measures can be adopted.

[0075] An embodiment of the present invention, as Figure 2 shown, a self-balancing control method is applied to the aforementioned ship medical operation platform, including:

[0076] Step S100 obtains the pose information of the lower platform of the ship medical operation platform at the current moment;

[0077] Step S200 obtains the relative motion information of the upper platform of the ship medical operation platform relative to the lower platform at the current moment;

[0078] Step S300 determines the relative motion information that the upper platform needs to correct according to the pose information of the lower platform at the current moment and the relative motion information of the upper platform at the current moment;

[0079] Step S400 determines the desired motion information of the actuator according to the relative motion information that the upper platform needs to correct;

[0080] Step S500 controls the actuator to drive the upper platform to move according to the desired motion information.

[0081] In one embodiment, obtaining the pose information of the lower platform at the current moment in step S100 includes:

[0082] Step S110 obtains the vibration information of the lower platform at the current moment through an inertial navigation unit;

[0083] Step S120 eliminates the bias and noise in the vibration information through a filtering algorithm to obtain the pose information of the lower platform at the current moment.

[0084] The inertial navigation unit may include some or all of a three-axis accelerometer, a three-axis gyroscope, and a three-axis magnetometer as needed, and the corresponding vibration information includes some or all of the three-axis acceleration and the three-axis angular velocity. Due to the bias and noise of the sensor itself, the data output by the sensor is not accurate, and direct integration will lead to rapid divergence. By eliminating the bias and noise in the vibration information through a filtering algorithm and then integrating, the pose information of the installation carrier with high precision can be obtained, including the roll angle, pitch angle, yaw angle, surge displacement, sway displacement, and heave displacement, etc. The filtering algorithm can adopt a complementary filtering algorithm, a Kalman filtering algorithm, or an extended Kalman filtering algorithm.

[0085] In one embodiment, obtaining the relative motion information of the upper platform relative to the lower platform at the current moment in step S200 includes:

[0086] Step S210 obtains the motion information of the actuator at the current moment through an encoder;

[0087] Step S220 performs a kinematic forward solution according to the motion information of the actuator at the current moment to obtain the relative motion information of the upper platform relative to the lower platform at the current moment.

[0088] Specifically, an actuator is provided between the upper platform and the lower platform. The actuator adopts a robot configuration, and the upper platform is the end of the robot. The motion information of the actuator includes displacement and speed, specifically including the displacement and speed of each motion chain. The displacement and speed of the corresponding motion chain can be obtained by using an encoder or a position / speed sensor provided in the actuator.

[0089] As Figure 3 shown, at the central positions of the lower platform and the upper platform, body-fixed coordinate systems O A x A y A z A and O B x B y B z B are respectively established. The upper platform is the task space or the operating space of the robot, and its 6D motion relative to the lower platform is Δx, Δy, Δz, Δα, Δβ, Δγ. The first three dimensions are relative translations, and the last three dimensions are relative rotations.

[0090] Assume that the joint space coordinates of the actuator connecting the upper platform and the lower platform are q1, q2, …, q n , respectively representing the motions of the corresponding joints in the 1-nth motion chains. According to the knowledge of geometry and robot kinematics, the forward kinematic solution of this robot can be derived as:

[0091]

[0092] where q = [q1, q2,..., q n T , ΔX = [Δx, Δy, Δz, Δα, Δβ, Δγ] T .

[0093] ΔX, are respectively the relative displacement and relative speed in the relative motion information of the upper platform relative to the lower platform, q, are respectively the displacement and speed of the actuator, and J is the velocity mapping Jacobian matrix of the inverse kinematics.

[0094] In one embodiment, step S300 includes:

[0095] Step S310 determines the control rate of the relative motion of the upper platform relative to the lower platform according to the pose information of the lower platform at the current moment and the relative motion information of the upper platform at the current moment.

[0096] Step S320 obtains the relative motion information that the upper platform needs to correct through numerical integration according to the control rate of the relative motion of the upper platform relative to the lower platform.

[0097] ​Specifically, to achieve the smoothness of the upper platform, the design goal of the task space control rate is to make the pose information of the upper platform in the inertial space as small as possible, equal to or approaching 0. Multiple control theories such as PID, ADRC, optimal control, robust control, and adaptive control can be used for the design.

[0098] Record the pose information of the lower platform in the inertial space at the current moment as: X A =[x A ,y A ,z A ,α A ,β A ,γ A T , then the pose information of the upper platform in the inertial space at the current moment is:

[0099] X B =X A +ΔX, X B =[x B ,y B ,z B ,α B ,β B ,γ B T , where ΔX is the relative displacement of the upper platform relative to the lower platform at the current moment.

[0100] As a preferred solution, taking PID control as an example, the control rate of the relative motion of the upper platform relative to the lower platform is obtained based on the following formula

[0101]

[0102]

[0103] where K P ,K D are relevant parameters, is the relative velocity of the upper platform relative to the lower platform at the current moment, X A is the pose information of the lower platform at the current moment, are the velocity and acceleration information of the lower platform at the current moment, respectively.

[0104] The relative motion information that the upper platform needs to correct is obtained by numerical integration. The relative motion information includes relative displacement and relative velocity.

[0105] In one embodiment, step S400 includes:

[0106] Step S410 performs kinematic inverse solution according to the relative motion information that the upper platform needs to correct, and obtains the expected displacement and expected velocity of the actuator. ​​

[0107] q t = f INV (ΔX t )

[0108] Among them, the expected displacement and expected speed of the actuator are obtained by using the formula , ΔX t , are the relative displacement and relative speed in the relative motion information that the upper platform needs to correct respectively, q t , are the expected displacement and expected speed of the actuator respectively, and J is the velocity mapping Jacobian matrix of inverse kinematics.

[0109] Then, the driving instruction of the actuator is generated according to the expected displacement and expected speed, and is executed by the actuator. The actual execution situation is fed back to the control unit through the encoder.

[0110] Considering the high safety requirements of the surgical platform, safety measures can also be added to the self-balancing control method of the shipboard medical surgical platform. For example, before the actuator executes, it is first judged whether the upper platform crosses the normal working range according to the expected displacement and expected speed. If it does not cross, the actuator executes the corresponding driving instruction; otherwise, the expected displacement and / or expected speed are reduced. The expected displacement and / or expected speed can be gradually reduced according to the preset step size until a safe expected displacement and / or expected speed is found, and it is judged that the upper platform will not cross the normal working range according to the safe expected displacement and expected speed.

[0111] In this embodiment, through the automatic adjustment of the parallel mechanism, the operating table can resist the fluctuations of the wind and waves during the navigation of the ship, and keep the plane of the operating table stable, that is, the plane of the operating table is basically stationary relative to the inertial coordinate system, so as to ensure the successful completion of the operation.

[0112] The present invention also provides a specific application scenario embodiment, providing a shipboard medical surgical platform, the appearance of which is as Figure 4 shown, and the structural schematic diagram is as Figure 5 shown.

[0113] This shipboard medical surgical platform consists of 2 modules:

[0114] Module 1 is the operating table, including ① the operating table surface; ② the occipital rotation shaft; ③ the lumbar rotation shaft; ④ the leg rotation shaft; ⑤ the lifting mechanism. This module is a 4-degree-of-freedom serial robot and can realize the dynamic adjustment of the posture of the wounded during the operation.

[0115] Module 2 is a stable platform, including ⑥ upper platform; ⑦ lower drag pedal; ⑧ parallel robot; ⑨ lower platform. The lower drag pedal is fixedly connected to the upper platform. Through the lower drag pedal, medical staff and the wounded can be on the stable platform at the same time, without being affected by the impact of sea waves. The operating table of Module 1 is fixedly connected to the upper platform of Module 2, and the height is reduced and the volume is reduced through an embedded design.

[0116] In addition to the above mechanical structure, the marine medical operating platform also includes the following electrical modules:

[0117] Inertial navigation unit, including a three-axis accelerometer, a three-axis gyroscope, a three-axis magnetometer and a GPS module, is fixed on the lower platform and can sense the position and attitude information of the ship. After being processed by the perception fusion algorithm, the real-time roll angle, pitch angle, yaw angle, surge displacement, sway displacement and heave displacement of the ship can be obtained.

[0118] Actuator, which can use servo electric cylinders, servo hydraulic cylinders, motor reducers, etc. as the actuators of each axis of the robot. Each actuator is equipped with a corresponding servo control board, which can make the actuator execute according to the desired instructions and feedback the execution results to the main control unit through an encoder.

[0119] Main control unit, which runs the core control algorithm and issues instructions to the actuator.

[0120] Power supply, cables, etc.

[0121] The working flow chart of the self-balancing function of the marine medical operating platform is as Figure 6 shown. When the self-balancing function is turned on, the operating table adjustment function of the platform can be normally turned on.

[0122] The specific implementation is as follows:

[0123] (1) Obtain the real-time pose information of the ship through the inertial navigation unit.

[0124] The inertial navigation unit installed on the lower platform (fixed on the deck) can measure the vibration information of the ship in real time, including 3-axis acceleration, 3-axis angular velocity, GPS position information, etc. The deviation and noise in the signal can be eliminated through complementary filtering algorithms, Kalman filtering algorithms, extended Kalman filtering algorithms, etc., and the high-precision pose information of the lower platform in the inertial space can be obtained, that is, the real-time roll angle, pitch angle, yaw angle, surge displacement, sway displacement and heave displacement.

[0125] (2) Robot kinematic analysis

[0126] As Figure 3As shown in the figure, at the central positions of the lower platform and the upper platform of the parallel robot's stable platform, body-fixed coordinate systems OAx Ay Az A and OBx By Bz B are respectively established. The upper platform is the task space or operation space of this parallel robot. Its six-dimensional motion relative to the lower platform is Δx, Δy, Δz, Δα, Δβ, Δγ. The first three dimensions are relative translations, and the last three dimensions are relative rotations. For a robot with n degrees of freedom, only n independent motions exist among the six-dimensional motions of the task space, and the other motions are coupled motions.

[0127] Assume that the joint space coordinates of the parallel robot's stable platform are q1, q2, …, q n , representing the motions of the 1st, 2nd, …, nth joints respectively. According to geometric and robot kinematics knowledge, the inverse kinematics solution of the robot can be derived as follows:

[0128]

[0129] Taking the derivative of the above formula, we get

[0130]

[0131] where J is the velocity mapping Jacobian matrix of the inverse kinematics.

[0132] Similarly, the forward kinematics solution of this robot can be derived as follows:

[0133]

[0134] where ΔX, are the relative displacement and relative velocity in the relative motion information of the upper platform relative to the lower platform respectively, and q, are the joint space displacement (displacement of the actuator) and joint space velocity (velocity of the actuator) respectively.

[0135] When vibration reduction is required for all six dimensions simultaneously, the parallel robot's active stable platform should satisfy n = 6.

[0136] (3) Task Space (Operation Space) Control Rate Design

[0137] Denote the ship vibration input vector measured by the inertial navigation unit as X A = [α A β A γ A x A y A z A T ,

[0138] where α A , β A , γ A , x​A , y A , z A are respectively the roll angle, pitch angle, yaw angle, surge displacement, sway displacement, and heave displacement of the lower platform (fixed on the ship deck).

[0139] The vibration output vector of the upper platform in the inertial space is

[0140] X B = [α B β B γ B x B y B z B T = X A + ΔX,

[0141] where α B , β B , γ B , x B , y B , z B are respectively the roll angle, pitch angle, yaw angle, surge displacement, sway displacement, and heave displacement of the upper platform. ΔX is the relative motion vector of the upper platform relative to the lower platform.

[0142] The design goal of the task space control law is to make the vibration output of the upper platform as small as possible, and various control theories such as PID, ADRC, optimal control, robust control, and adaptive control can be used for design.

[0143] Here, taking PID control as an example as an optimal solution, the control law of the task space is set as

[0144]

[0145]

[0146] where K P , K D are the control parameters of PID.

[0147] After calculating the at time t, by using numerical integration, the expected displacement and expected velocity of the parallel robot in the task space at time t can be obtained as ΔX t and

[0148] (4) Joint space drive command resolution

[0149] According to the inverse kinematics of the robot, the expected displacement and expected velocity in the joint space at time t (i.e., the expected displacement and expected velocity of the actuator) are respectively:[[]]​

[0150] q t = f INV (ΔX t )

[0151]

[0152] The servo driver executes according to the set displacement and speed commands.

[0153] (5) The actuator executes the drive command and feeds back the execution status through the encoder.

[0154] The encoder in the servo driver feeds back the actual execution status of the actuator to the control system in real time.

[0155] The control flow chart is as Figure 7 shown.

[0156] Result analysis:

[0157] Build a marine medical operation platform in the dynamics simulation software Adams, where the parallel robot stable platform at the bottom adopts a 6-degree-of-freedom Stewart configuration. According to the aforementioned design method, build a control law in the Simulink software and connect it with the Adams software for Adams+Simulink co-simulation.

[0158] Apply a composite excitation to the lower platform of the model, and the excitation components in each dimension are as follows:

[0159] Surge excitation (x direction) is a sine wave with an amplitude of 100 mm and a frequency of 1 Hz;

[0160] Sway excitation (y direction) is a sine wave with an amplitude of 200 mm and a frequency of 0.6 Hz;

[0161] Heave excitation (z direction) is a sine wave with an amplitude of 500 mm and a frequency of 0.8 Hz;

[0162] Roll excitation (α direction) is a sine wave with an amplitude of 20° and a frequency of 0.7 Hz;

[0163] Pitch excitation (β direction) is a sine wave with an amplitude of 10° and a frequency of 0.5 Hz;

[0164] Yaw excitation (γ direction) is a sine wave with an amplitude of 6° and a frequency of 0.3 Hz.

[0165] Adopt PID control, and the control parameters are set as k P = 1000, k D = 60.

[0166] The simulation results are as Figure 8 and Figure 9As shown, it can be seen that the ship medical operation platform can effectively reduce the rolling, pitching, yawing, swaying, heaving and surging of the ship, and the vibration reduction efficiency in each dimension reaches more than 98%, enabling medical staff to perform operations with the same physical feeling as in a land hospital, effectively improving the operation efficiency and success rate.

[0167] The ship medical operation platform provided in this embodiment is based on the principle of active vibration reduction, which can actively reduce or even eliminate the influence of ship rolling, pitching, yawing, swaying, heaving and surging, achieving all-round vibration reduction in 6 dimensions, and the vibration reduction effect can reach more than 98%. By designing the control rate in the task space of the robot, it can be free from the limitation of the robot configuration adopted by the bottom stable platform and achieve standardized high-precision control. Through the integrated design using the series-parallel hybrid robot technology, the bottom adopts a parallel robot structure to achieve the balance function of multiple degrees of freedom, the top adopts a serial robot structure to achieve the attitude dynamic adjustment function of the operating bed, and the lower drag pedal ensures no relative movement between medical staff and the wounded and sick. The embedded design and retractable structure greatly reduce the volume of the platform, realizing the integration of the stable platform and the operating table in a limited space, enabling medical staff to isolate the influence of sea waves and perform operations with the physical feeling of a land hospital, effectively improving the success rate and efficiency of operations.

[0168] It should be noted that the above embodiments can be freely combined according to needs. The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A marine medical operation platform, characterized in that, It includes an operating table and a stabilizing platform located below the operating table; The stabilizing platform includes a parallel mechanism, a lower drag pedal, an inertial navigation unit, an encoder, and a control unit; The parallel mechanism includes an upper platform, a lower platform, and an actuator connected between the upper platform and the lower platform; the upper platform is fixedly connected to the operating table, the lower platform is fixedly installed on the deck of the hull, and the actuator can drive the upper platform; the actuator includes multiple independent kinematic chains, and each kinematic chain uses a servo cylinder for telescopic movement; The lower drag pedal is fixedly connected to the upper platform; The inertial navigation unit is fixedly installed on the lower platform for obtaining the vibration information of the lower platform; The encoder is installed on the actuator for detecting the motion information of the actuator; The control unit is electrically connected to the encoder and the inertial navigation unit, and actively controls the operation of the actuator based on the vibration information of the lower platform, the motion information of the actuator, and the kinematic relationship between the upper platform and the lower platform, so that the upper platform remains stable during the ship's voyage.

2. The marine medical operating platform according to claim 1, wherein The operating table includes an operating table surface; The operating table surface is divided into four parts, wherein the first part and the second part are connected by a pillow shaft, the second part and the third part are connected by a waist shaft, and the third part and the fourth part are connected by a leg shaft.

3. The marine medical operating platform according to claim 2, wherein The operating table further includes a lifting mechanism, and the lifting mechanism is located below the operating table surface and is embedded in the upper platform.

4. The marine medical operating platform according to claim 1, wherein The parallel mechanism adopts a 6-degree-of-freedom stewart configuration.

5. The marine medical operating platform according to claim 1, wherein Limit switches are respectively installed at the end of the stroke of the servo cylinder.

6. The marine medical operating platform according to claim 1, wherein A variable stiffness spring is nested outside the servo cylinder, and / or an anti-collision spring or anti-collision pad is added at the end of the stroke of the servo cylinder.

7. The marine medical operating platform according to claim 1, wherein The kinematic chain includes a servo hydraulic cylinder and a hydraulic locking circuit, the hydraulic locking circuit is connected to the oil inlet and outlet of the servo hydraulic cylinder, and the hydraulic locking circuit uses an overflow valve, a three-position four-way directional control valve, and two pilot-operated check valves to achieve self-locking of the servo hydraulic cylinder.

8. The marine medical operating platform according to claim 1, wherein A number of safety columns are installed around the parallel mechanism, the safety columns are located at the boundary points of the task space of the parallel robot, the inside of the safety columns is a rigid column body, and the outside is wrapped with an elastic material; Each safety column is connected to the upper platform of the parallel mechanism through a passive branch chain, and the passive branch chain has more than 6 degrees of freedom and adopts a UPS or SPS configuration.

9. A self-balancing control method is applied to the marine medical operation platform according to any one of claims 1-8, characterized in that, It includes: Obtaining the pose information of the lower platform of the marine medical operating platform at the current moment; Obtain the relative motion information of the upper platform of the ship medical operation platform relative to the lower platform at the current moment; Determine the relative motion information that the upper platform needs to correct according to the pose information of the lower platform at the current moment and the relative motion information of the upper platform at the current moment; Determine the desired motion information of the actuator according to the relative motion information that the upper platform needs to correct; Control the actuator to drive the upper platform to move according to the desired motion information.

10. The self-balancing control method according to claim 9, wherein The step of determining the relative motion information that the upper platform needs to correct according to the pose information of the lower platform at the current moment and the relative motion information of the upper platform at the current moment includes: Determine the control rate of the relative motion of the upper platform relative to the lower platform according to the pose information of the lower platform at the current moment and the relative motion information of the upper platform at the current moment; Obtain the relative motion information that the upper platform needs to correct through numerical integration according to the control rate of the relative motion of the upper platform relative to the lower platform.

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