Puncture force simulation method based on force feedback

Abstract

The present invention relates to a force feedback force simulation method, and in particular to a puncture force simulation method based on force feedback, comprising: step S1, configuring a virtual model tissue to be a two-layer structure comprising an epidermis and a dermis; step S2, determining the distance between an initial reset point and a first-layer needle insertion point, and configuring a limiting force in the model tissue; step S3, configuring tissue layer puncture parameters, the parameters including the thickness of a breakthrough zone and the thickness of an effect zone, the maximum forward penetration force, the maximum reverse withdrawal force, the forward damping coefficient, the reverse damping coefficient, the upward rotation angle, the downward rotation angle, the viscosity coefficient, and the friction coefficient; and step S4, advancing the device in any direction from the initial point until the device contacts the first-layer puncture point. The present invention can simulate the force sense of puncture displacement at any angle, and by defining and configuring the simulated breakthrough zone and the effect zone, it is fully realized in three-dimensional space without the need for a dimensionality reduction mapping space.

Description

Technical Field

[0001] The present invention relates to a force feedback force sensation simulation method, and in particular to a puncture force sensation simulation method based on force feedback. Background Art

[0002] With the advancement of medical technology, virtual medical simulation offers an innovative approach to medical education and training. Traditional medical education typically relies on classroom instruction and real-world clinical experience. However, virtual medical simulation, by simulating real-world medical scenarios and disease conditions, provides medical students and physicians with a more realistic, interactive, and controllable learning environment. This strengthens theoretical learning of medical knowledge and the development of practical skills, thereby enhancing physicians' professional expertise and clinical decision-making abilities. Virtual medical simulation can also improve medical safety and reduce medical errors. Through virtual medical simulation, medical staff can conduct extensive operational practice and teamwork training in a simulated environment, becoming familiar with medical procedures, operating techniques, and emergency response, thereby reducing surgical risks and improving medical quality. Virtual medical simulation can also be used to train and improve patient care skills, providing more professional nursing services. To meet the demand for simulation of puncture scenarios in clinical surgery or nursing care, there is an urgent need for a puncture force simulation method that combines force feedback devices with virtual and real-world feedback to provide the operator with a sense of puncture force. Summary of the Invention

[0003] The technical problem to be solved by the present invention is that the existing technical solutions have steps of converting from 3D to 2D space, and steps of ray collision detection. The operation position of determining the position relationship between the puncture needle and the tissue is limited and the steps are complicated, and additional mapping is required to describe the tissue to be punctured. A puncture force simulation method is provided that uses a force feedback device to simulate the force feedback of the puncture needle in a medical puncture scene, which can be applied to the puncture simulation of tissues such as skin, muscle, and joint cavity.

[0004] The technical problem to be solved by the present invention is achieved through the following technical solutions. The present invention discloses a puncture force simulation method based on force feedback, which includes the following steps: step S1, configuring the virtual model tissue as a two-layer structure including the epidermis and the dermis, and configuring the device reset point as a fixed point in the three-dimensional space, initializing the force feedback device to the reset position; step S2, determining the distance between the initial reset point and the first-layer needle insertion point, configuring the limiting force in the model tissue, and the limiting force is decomposed into two orthogonal limiting components perpendicular to the insertion direction at the insertion point according to the device's own coordinate system; step S3, configuring the tissue layer puncture parameters, the parameters including the thickness of the breakthrough area and the thickness of the effect area, the maximum forward insertion force, the maximum reverse withdrawal force, the forward damping coefficient, the reverse damping coefficient, the forward damping coefficient, the reverse damping coefficient, the reverse direction ... Upward rotation angle, downward rotation angle, viscosity coefficient and friction coefficient; step S4, after the device is moved forward in any direction from the initial point, the device contacts the first-layer puncture point, and continues to insert the needle to puncture into the tissue. Before reaching the critical point, the device is in the breakthrough area, and the device feedback force is configured as the superposition of the breakthrough feedback force and the restriction force; step S5, after the device moves to the critical point, it continues to puncture into the effect area. At this time, the breakthrough feedback force is reduced to produce a breakthrough feeling. The feedback force of the device entering the effect area is configured as a multi-force superposition including the restriction force, viscosity force and friction force; step S6, the device continues to insert the needle to puncture into the tissue until it reaches the needle insertion point of the next breakthrough area, and jumps to step S4 according to the parameter configuration of the next layer to continue the operation until the entire simulation operation process is completed.

[0005] The technical problem to be solved by the present invention can be further achieved by the following technical solution, wherein step S1 includes configuring each layer of the two-layer structure of the model into two areas, a breakthrough area and an effect area, wherein the breakthrough area is used to simulate the feeling of piercing the epidermis and / or fascia structure; and the effect area is used to simulate the feeling of resistance of the puncture needle moving in the muscle and / or fat tissue.

[0006] The technical problem to be solved by the present invention can also be further achieved through the following technical solution, wherein the upper and lower parts of the epidermis layer are respectively provided with adjacent breakthrough areas and effect areas, and the upper and lower parts of the dermis layer are respectively provided with adjacent breakthrough areas and effect areas, and the effect area of ​​the lower part of the epidermis layer is adjacent to the breakthrough area of ​​the upper part of the dermis layer.

[0007] The technical problem to be solved by the present invention can be further achieved through the following technical solution, in which the maximum forward penetration force and / or the maximum reverse withdrawal force in step S3 are configured to produce a breakthrough effect in the breakthrough area, and the device will continue to be hindered from moving by the reverse resistance of the tissue in the initial to critical interval. When the resistance reaches a certain threshold, it decreases instantly, and the breakthrough force feeling of the tissue being punctured is simulated by the sudden change of the front and rear resistance.

[0008] The technical problem to be solved by the present invention can be further achieved by the following technical solution, wherein the forward damping coefficient and / or reverse damping coefficient in step S3 are configured so that when the device is in the breakthrough zone, a damping force is superimposed on the breakthrough force, and the damping force is calculated according to the current moving speed of the device, and the direction of the damping force is opposite to the direction of the speed.

[0009] The technical problem to be solved by the present invention can also be further achieved through the following technical solution, wherein the upward rotation angle and / or downward rotation angle in step S3 are configured to determine the magnitude of the limiting force of the effect area, and when the device enters the effect area in the forward direction, it is configured according to the upward / downward rotation angle parameters.

[0010] The technical problem to be solved by the present invention can be further achieved by the following technical solution, wherein the critical point in step S4 and step S5 is configured as the needle entry point of the effect area, and the needle entry point of the effect area is configured to be located at the critical surface between the breakthrough area and the effect area.

[0011] Compared with the prior art, the present invention has the following advantages:

[0012] (1) The present invention can simulate the displacement force of puncture at any angle. By defining and configuring the simulated breakthrough area and effect area, it is fully realized in three-dimensional space without the need for dimensionality reduction mapping space. It only relies on the layer model to describe the tissue to be punctured without relying on additional mapping;

[0013] (2) The present invention achieves a rich puncture force sense by dividing different puncture stages and configuring the force sense of the model's multi-layer puncture area, combining parameters such as breakthrough force, friction force, viscosity force, and restriction force for superposition configuration, and utilizing multiple effects and superimposed feedback;

[0014] (3) The present invention can be combined with application scenarios to propose a method of rotation after puncturing the tissue. The angle can be controlled by parameters to simulate the operation of real intravenous infusion medical care. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the real-time puncture structure of the present invention;

[0016] Figure 2 This is a schematic diagram of the needle insertion point coordinate system according to an embodiment of the present invention;

[0017] Figure 3 This is a schematic diagram of the changes in the puncture layer after rotation according to an embodiment of the present invention; DETAILED DESCRIPTION

[0018] like Figure 1-3As shown, the force feedback-based puncture force simulation method disclosed in the present invention includes the following steps: step S1, configuring the virtual model tissue as a two-layer structure including the epidermis and the dermis, and configuring the device reset point as a fixed point in three-dimensional space, initializing the force feedback device to the reset position; step S2, determining the distance between the initial reset point and the first-layer needle insertion point, configuring the limiting force in the model tissue, and the limiting force is decomposed into two orthogonal limiting components perpendicular to the insertion direction at the insertion point according to the device's own coordinate system; step S3, configuring the tissue layer puncture parameters, the parameters including the thickness of the breakthrough area and the thickness of the effect area, the maximum forward insertion force, the maximum reverse withdrawal force, the forward damping coefficient, the reverse damping coefficient, the upward rotation angle, the downward rotation angle, the Angle, viscosity coefficient and friction coefficient; step S4, after the device is advanced from the initial point in any direction, the device contacts the first-layer puncture point, and continues to insert the needle to puncture into the tissue. Before reaching the critical point, the device is in the breakthrough zone, and the device feedback force is configured as the superposition of the breakthrough feedback force and the restriction force; step S5, after the device moves to the critical point, it continues to puncture into the effect zone. At this time, the breakthrough feedback force is reduced to produce a breakthrough feeling. When entering the effect zone, the device feedback force is configured as a multi-force superposition including the restriction force, viscosity force and friction force; step S6, the device continues to insert the needle to puncture into the tissue until it reaches the needle insertion point of the next breakthrough zone, and jumps to step S4 according to the parameter configuration of the next layer to continue the operation until the entire simulation operation process is completed.

[0019] Step S1 includes configuring each layer of the two-layer structure of the model into two regions: a breakthrough region and an effect region. The breakthrough region is used to simulate the sensation of puncturing the epidermis and / or fascia; the effect region is used to simulate the resistance of a puncture needle moving through muscle and / or adipose tissue. Specifically, adjacent breakthrough regions and effect regions are provided in the upper and lower portions of the epidermis, respectively, and adjacent breakthrough regions and effect regions are provided in the upper and lower portions of the dermis, respectively, with the effect region in the lower epidermis being adjacent to the breakthrough region in the upper dermis.

[0020] The forward maximum penetration force and / or the reverse maximum withdrawal force in step S3 are configured to produce a breakthrough effect in the breakthrough zone. The device will continue to be hindered from moving by the reverse resistance of the tissue in the initial to critical interval. When the resistance reaches a certain threshold, it will instantly decrease, and the breakthrough force sensation of the tissue being punctured will be simulated by the sudden change of the front and rear resistance. Wherein, the forward damping coefficient and / or the reverse damping coefficient are configured so that when the device is in the breakthrough zone, a damping force will be superimposed on the breakthrough force, and the damping force is calculated according to the current moving speed of the device, and the direction of the damping force is opposite to the direction of the speed. Wherein, the upward rotation angle and / or the downward rotation angle are configured to determine the size of the limiting force in the effect zone. When the device enters the effect zone in the forward direction, it is configured according to the upward / downward rotation angle parameters.

[0021] The critical point in step S4 and step S5 is configured as the needle entry point of the effect area, and the needle entry point of the effect area is configured to be located at the critical surface between the breakthrough area and the effect area.

[0022] The following will further describe the above simulation method with the help of real-time examples:

[0023] The process of tissue puncture can be divided into two different force sensations: breakthrough sensation and resistance sensation. Taking abdominal puncture as an example, the breakthrough sensation is manifested in the obvious puncture sensation when the puncture needle pierces the skin. When the puncture continues and encounters the peritoneum, a puncture sensation should be felt again. After puncturing into the tissue, the needle tip should be subject to resistance from the fat when entering the fat, resistance from the muscle when entering the muscle, and resistance from the tissue fluid when moving the needle. Different resistances correspond to different force sensations. Therefore, the present invention designs a corresponding layer model to quantitatively describe the punctured tissue structure to achieve a rich force sensation effect.

[0024] Figure 1 As an example, assume that tissue consists of two layers: the epidermis and the dermis. The model divides each layer into two regions: a breakthrough zone and an effect zone. The breakthrough zone simulates the sensation of piercing structures such as the epidermis or fascia; the effect zone simulates the resistance of a puncture needle through tissues such as muscle or fat.

[0025] Premise: The virtual puncture needle is the force feedback device (hereinafter referred to as the device), and the device point is the tip of the device, which is recorded as point The reset point of the device is a fixed point in the three-dimensional space (for different embodiments, the initial position of the reset point in the three-dimensional space is the same), denoted as point When resetting, the device point moves to the reset point. The world coordinate system and the device coordinate system are both right-handed coordinate systems. In the world coordinate system, the device coordinate system is expressed as like Figure 2 shown.

[0026] Outside the puncture tissue, the device can rotate around the reset point along any axis at any angle; without special scenes and instructions, the direction of the device is only the direction of its own coordinate system. Axis direction, The vector is denoted as The maximum feedback force of the force feedback is MAX_FORCE. The Z-axis movement range of the force feedback device in its working space is 0 to MAX_Z.

[0027] The operation steps of this embodiment are as follows: initialize the force feedback device to the reset position, determine the initial point The distance between the needle insertion point and the first layer is recorded as the initial distance d (after determining d, the initial distance The sphere S is determined in three-dimensional space with a radius of d. Therefore, any point on the surface of S may become a virtual first-layer needle insertion point in three-dimensional space. When the device actually reaches a point on the surface of S, the point is determined as the virtual first-layer needle insertion point, which is recorded as point At the same time, determine the needle insertion direction as the current Recorded as The current local coordinate system The axis is denoted as The current local coordinate system The axis is denoted as In the real world, when the puncture needle penetrates the tissue, it will maintain its axial direction when no external force is applied to the puncture needle. This is because the puncture needle will be squeezed by the surrounding tissue and will not deviate to other directions. For example, if a thin stick is inserted vertically downward into the soil, it will not fall down after being released. In the present invention, this effect is achieved by limiting the force. After the device penetrates the tissue, the limiting force can be decomposed into the device's own coordinate system along the penetration point according to the force decomposition. Axis force He Yan Axis The direction of insertion is After the device enters the tissue, the force will continue to exist Limit edge Direction deviation Axis; exists in the breakout zone Limit the equipment in the breakthrough area Direction deviation axis, in the effect area, Controlled by the UpRotationAngle / UpRotationAngle parameter)

[0028] First, configure the puncture tissue layer structure. The parameters for each layer are configured as follows:

[0029]

[0030]

[0031] Breakthrough zone thickness hp; when the puncture process is determined After that, the needle insertion point of the effect area can be determined by HP and recorded as point

[0032]

[0033] Thickness of effect area he; Needle insertion point of effect area After that, the next breakthrough point can be determined and recorded as point

[0034]

[0035] Forward (penetration) maximum force / reverse (extraction) maximum force; the breakthrough zone produces a breakthrough effect, the device to In this range, the device will continue to be subjected to the reverse resistance of the tissue, hindering the movement of the device. When the resistance reaches a certain threshold, it will instantly decrease. The sudden change of the front and rear resistances will produce a breakthrough effect, simulating the force of the tissue being punctured. When the device is in the breakthrough zone, it will continue to output feedback force, which is recorded as

[0036] When the device is moving forward, to At this point, the device begins to add positive breakthrough force. As the device moves to point, the positive breakthrough feedback force reaches the maximum value forcePos, when it exceeds When the positive breakthrough feedback force is immediately reduced to 0, the feedback force suddenly decreases, and the difference in front and back resistance forms a sense of breakthrough force.

[0037]

[0038] Reverse (extraction) maximum force; when the device moves in the reverse direction (extraction operation force simulation, that is, from to At this point, the device begins to add reverse breakthrough force, which also simulates the obstruction of the tissue structure on the device movement. point, the reverse breakthrough feedback force reaches the maximum value forceNeg, when the reverse exceeds When the reverse breakthrough feedback force is immediately reduced to 0

[0039]

[0040] Forward damping coefficient / reverse damping coefficient; when the device is in the breakthrough zone, the damping force will be superimposed on the breakthrough force. The direction of the damping force is opposite to the speed direction according to the current moving speed of the device. The current speed of the device is recorded as The damping force is recorded as

[0041] Forward:

[0042] Reverse:

[0043] Upward rotation angle / downward rotation angle; determines the limiting force of the effect area When the device enters the effect area, according to the configuration of the upward / downward rotation angle parameters, is the rotation origin, around The axis rotates, for example Figure 3 , after the device rotates, the next layers are The center of the circle is deformed into concentric circles to ensure that the HP and HE of each layer are the same at all angles. It is mainly used in intravenous injection scenarios to meet the operation process that requires first inserting the needle into the blood vessel, then rotating it to a horizontal position, and then inserting the needle.

[0044]

[0045] when Time, remember Around The unit vector of the axis rotation upAngle degrees is recorded as

[0046]

[0047] when Time, remember Around The unit vector of the axis rotation downAngle degrees is recorded as

[0048]

[0049] The calculation formula is as follows: Therefore, the calculation by As a reference point

[0050]

[0051] When in the breakout zone, The calculation is as follows:

[0052]

[0053] Maximum viscosity / viscosity coefficient; Viscosity comes from the effect of the liquid in the tissue on the puncture needle, such as blood, joint fluid, etc. The magnitude of the viscosity is related to the type of liquid. For example, a thin rod stirring water and stirring oil are two force sensations, described by the parameter viscousCoef; The magnitude of the viscosity is also related to the speed of the device in the liquid. The greater the speed, the greater the resistance should be. The direction of the viscosity is opposite to the direction of the speed; The effect area can generate viscosity to simulate the resistance of the liquid in the tissue to the puncture needle. Viscosity Calculated based on the device's current moving speed

[0054]

[0055] Maximum friction force / friction coefficient; Friction force comes from the effect of the penetrated tissue on the device, which hinders the movement of the device along its insertion direction. For example, if you hold a thin rod tightly with your hand and push and pull it along its axis, the resistance generated by the palm of your hand on the thin rod will generate a force on the contact surface that hinders relative motion. The direction of the resultant friction force is opposite to the insertion direction of the device. The magnitude of the friction force is simplified to the product of the friction coefficient and the relative displacement. According to the deviation calculation between the current position of the device and the position of the previous frame, the device position of the previous frame is recorded as The friction force of the current frame is

[0056]

[0057] The device starts from the initial point Along any After moving forward in the direction of d, the device contacts the first-floor puncture point

[0058]

[0059] Continue to insert the needle into the tissue and reach Before the point, the device is in the breakthrough zone, and the feedback force

[0060]

[0061] The equipment moves to After clicking, continue to pierce into the effect area. Reduce the sense of breakthrough and the feedback force of the equipment entering the effect area

[0062]

[0063] Continue to insert the needle into the tissue until the needle point of the next breakthrough area is reached Jump to step 5 to continue according to the parameter configuration of the next layer.

[0064] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A puncture force simulation method based on force feedback, characterized by: The method comprises the following steps: step S1, configuring the virtual model tissue as a two-layer structure including an epidermis layer and a dermis layer, configuring the device reset point as a fixed point in three-dimensional space, and initializing the force feedback device to the reset position; Step S2: determining the distance between the initial reset point and the first-layer needle insertion point, configuring a limiting force in the model tissue, and decomposing the limiting force into two orthogonal limiting force components perpendicular to the insertion direction at the insertion point according to the device's own coordinate system; Step S3, configuring tissue layer puncture parameters, including breakthrough zone thickness and effect zone thickness, forward penetration maximum force, reverse withdrawal maximum force, forward damping coefficient, reverse damping coefficient, upward rotation angle, downward rotation angle, viscosity coefficient, and friction coefficient; Step S4: After the device is advanced in any direction from the initial point, the device contacts the first-layer puncture point and continues to puncture the tissue. Before reaching the critical point, the device is in the breakthrough zone, and the device feedback force is configured to be the superposition of the breakthrough feedback force and the limiting force. Step S5: After the device reaches the critical point, it continues to penetrate into the effect area. At this time, the breakthrough feedback force is reduced to produce a breakthrough feeling. The feedback force of the device entering the effect area is configured to be a superposition of multiple forces including a limiting force, a viscous force, and a friction force. Step S6, the device continues to insert the needle to puncture into the tissue until it reaches the needle insertion point of the next breakthrough area, and jumps to step S4 according to the parameter configuration of the next layer to continue the operation until the entire simulation operation process is completed.

2. The method for simulating puncture force sensation based on force feedback according to claim 1, characterized in that: The step S1 includes configuring each layer of the two-layer structure of the model into two areas, a breakthrough area and an effect area. The breakthrough area is used to simulate the breakthrough feeling of piercing the epidermis and / or fascia structure; the effect area is used to simulate the resistance feeling of the puncture needle moving in the muscle and / or fat tissue.

3. The method for simulating puncture force sensation based on force feedback according to claim 1, characterized in that: The upper and lower parts of the epidermis layer are respectively provided with adjacent breakthrough areas and effect areas, and the upper and lower parts of the dermis layer are respectively provided with adjacent breakthrough areas and effect areas. The effect area of ​​the lower epidermis layer is adjacent to the breakthrough area of ​​the upper dermis layer.

4. The method for simulating puncture force sensation based on force feedback according to claim 1, characterized in that: The maximum forward penetration force and / or the maximum reverse withdrawal force in step S3 are configured to produce a breakthrough effect in the breakthrough area. The device will continue to be hindered from moving by the reverse resistance of the tissue in the initial to critical interval. When the resistance reaches a certain threshold, it will instantly decrease, and the sudden change in the forward and backward resistance will simulate the breakthrough force feeling of the tissue being punctured.

5. The method for simulating puncture force sensation based on force feedback according to claim 1, characterized in that: The forward damping coefficient and / or reverse damping coefficient in step S3 is configured such that when the device is in the breakthrough zone, a damping force is superimposed on the breakthrough force, and the damping force is calculated according to the current moving speed of the device, and the direction of the damping force is opposite to the direction of the speed.

6. The method for simulating puncture force sensation based on force feedback according to claim 1, characterized in that: The upward rotation angle and / or downward rotation angle in step S3 is configured to determine the magnitude of the limiting force of the effect area. When the device enters the effect area in the forward direction, it is configured according to the upward / downward rotation angle parameters.

7. The method for simulating puncture force sensation based on force feedback according to claim 1, characterized in that: The critical point in step S4 and step S5 is configured as the needle entry point of the effect area, and the needle entry point of the effect area is configured to be located at the critical surface between the breakthrough area and the effect area.

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