A cutting robot with active precision constraint function

Abstract

The present invention discloses a cutting robot with an active precision constraint function, which relates to the field of medical robots. The cutting robot comprises: a first connecting member, one end of which is used to be connected to a 3D-printed guide plate; a second connecting member, one end of which is connected to the other end of the first connecting member, and the other end of the second connecting member is connected to a scalpel via a third connecting member, wherein the first connecting member, the second connecting member and the third connecting member are all hingedly connected; an optical positioning and tracking system, comprising a marker rigid body and a passive marker ball, wherein the marker rigid body is arranged on the 3D-printed guide plate, and the passive marker ball is arranged at the end of the scalpel; when a dynamometer applies a pulling force to the end of the scalpel, the optical positioning and tracking system records the displacement of the passive marker ball, and the recorded multiple sets of displacement data are used to debug the scalpel; after multiple dynamometer tests, the obtained data is processed and used as a basis for adjusting the setting parameters of the scalpel, so that calibration is simple and convenient, and avoids affecting the normal use of the cutting robot.

Description

Technical Field

[0001] This invention belongs to the field of medical robots, and more specifically, relates to a cutting robot with active precision constraint function. Background Art

[0002] In total knee replacement surgery, using a cutting robot instead of a dedicated osteotomy saw to cut bone tissue significantly improves surgical efficiency. However, with prolonged or frequent use, the cutting robot's movement accuracy can decrease, often leading to serious consequences. To improve the surgical accuracy of the cutting robot, regular precision calibration is necessary. This calibration process requires multiple pieces of equipment and is time-consuming, reducing the robot's overall efficiency. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing technologies by providing a cutting robot with active precision constraint function. This cutting robot is equipped with an optical positioning and tracking system. When the scalpel stops at a certain position, a force is applied to the end of the scalpel by a force gauge. The displacement of the scalpel end is measured by a marker rigid body and a passive marker ball. When the displacement is greater than a set threshold, the force count value is obtained. After multiple force gauge tests, the obtained data is processed and used as the basis for adjusting the setting parameters of the scalpel. This calibration is simple and convenient and avoids affecting the normal use of the cutting robot.

[0004] To achieve the above objectives, the present invention provides a cutting robot with active precision constraint function, comprising:

[0005] The first connector has one end for connecting to the 3D printing guide plate;

[0006] The second connector has one end connected to the other end of the first connector, and the other end of the second connector is connected to the scalpel through the third connector. The first connector, the second connector and the third connector are all connected by hinges.

[0007] An optical positioning and tracking system includes a marker rigid body and a passive marker ball, wherein the marker rigid body is disposed on the 3D printed guide plate and the passive marker ball is disposed at the end of the scalpel;

[0008] When the force gauge applies a pulling force to the end of the scalpel, the optical positioning and tracking system records the displacement of the passive marker ball. The multiple sets of displacement data recorded by the optical positioning and tracking system are used to adjust the scalpel.

[0009] Optionally, the optical positioning and tracking system uses a positioning tracker to obtain the position information of the passive marker ball.

[0010] Optionally, the marker rigid body is fixed to the 3D printed guide plate by hot melt adhesive, and the passive marker ball is fixed to the end of the scalpel by hot melt adhesive and bolt connection.

[0011] Optionally, the displacement data of the passive marker ball is saved using NDI Track software.

[0012] Optionally, the optical positioning and tracking system can also perform planar accuracy calculations and coordinate accuracy calculations on the scalpel.

[0013] Optionally, the rotation axes of the first connector, the second connector, and the third connector are parallel to each other, and the rotation angle between the first connector, the second connector, the third connector, and the scalpel is controlled by a control unit.

[0014] Optionally, a hinge structure for connecting the control unit is provided between the second connector and the third connector, the hinge structure comprising:

[0015] A connector is provided with a first rotating motor at one end, and the output end of the first rotating motor is connected to the other end of the second connector.

[0016] A second rotating motor is located at the other end of the connecting base, and the output end of the second rotating motor is connected to one end of the third connecting member.

[0017] Optionally, both the first rotary motor and the second rotary motor are dual-axis rotary motors.

[0018] Optionally, a single-axis servo motor connected to the control unit is provided between the first connector and the second connector, and between the third connector and the scalpel.

[0019] Optionally, the first connector and the 3D printing guide plate are connected by a quick-release pin, and one end of the first connector is connected to the midpoint of the 3D printing guide plate.

[0020] This invention provides a cutting robot with active precision constraint function. Its advantages are: the cutting robot uses data collected by an optical positioning and tracking system as a standard to calculate the cutting robot's planar accuracy, coordinate calculation accuracy and active constraint accuracy, and can periodically detect the accuracy of the scalpel without the need for additional detection equipment, thus not affecting the efficiency of the cutting robot.

[0021] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0022] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the invention.

[0023] Figure 1 A schematic diagram of a cutting robot with active precision constraint function according to an embodiment of the present invention is shown.

[0024] Explanation of reference numerals in the attached figures:

[0025] 1. First connector; 2. Second connector; 3. Third connector; 4. 3D printed guide plate; 5. Scalpel; 6. Connector; 7. First rotating motor; 8. Quick release pin; 9. Single-axis servo motor. DETAILED DESCRIPTION

[0026] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0027] This invention provides a cutting robot with active precision constraint function, comprising:

[0028] The first connector has one end for connecting to the 3D printing guide plate;

[0029] The second connector has one end connected to the other end of the first connector, and the other end of the second connector is connected to the scalpel through the third connector. The first connector, the second connector and the third connector are all connected by hinges.

[0030] An optical positioning and tracking system includes a marker rigid body and a passive marker ball. The marker rigid body is set on a 3D printed guide plate, and the passive marker ball is set on the tip of a scalpel.

[0031] When the tension gauge applies tension to the end of the scalpel, the optical positioning and tracking system records the displacement of the passive marker ball. The multiple sets of displacement data recorded by the optical positioning and tracking system are used to adjust the scalpel.

[0032] Specifically, this cutting robot with active precision constraint function is fixedly connected to a 3D printed guide plate via a first connector. The robot contains a first connector, a second connector, and a third connector, which are hinged together and ultimately connected to a scalpel. When the precision of the scalpel tip needs to be calibrated, a force gauge applies force to the tip. When the displacement of the marked rigid body exceeds a set threshold, the force gauge value is recorded. This process is repeated to measure multiple sets of data. The measured data are processed using Python to calculate the distance of deviation from the coordinate origin. Based on this deviation distance, the connection structure of the cutting robot is adjusted to increase its connection strength. Furthermore, when the force on the scalpel exceeds the set threshold, a pre-set allowance is made for the scalpel's position according to the deviation distance. This ensures that after the scalpel is subjected to force and deviates, it returns to the standard position, guaranteeing the scalpel's positional accuracy without requiring excessive testing equipment and time for dedicated positional accuracy testing.

[0033] Optionally, the optical positioning and tracking system uses a positioning tracker to obtain the position information of the passive marker ball.

[0034] Specifically, the optical positioning and tracking system can track the 3D position of the passive marker ball on the scalpel in real time. It uses a positioning tracker (tracker positioning tool) to track the passive wireless marker using near-infrared light and can track multiple passive marker balls simultaneously within a large pre-calibrated measurement range.

[0035] Optionally, the marker rigid body is fixed to the 3D printed guide plate using hot melt adhesive, and the passive marker ball is fixed to the end of the scalpel using both hot melt adhesive and bolt connection.

[0036] Specifically, during the active precision constraint function test of the scalpel tip, a marker rigid body and a passive marker sphere were fixed to the 3D-printed guide plate and the scalpel, respectively. For precision measurement, a specific rigid body from NDI Polaris was used as the marker rigid body for optical position tracking, and the zero point of the marker rigid body was used as the zero point of the optical positioning and tracking system. In the Arduino control program, correction factors were added to the x-axis and y-axis to ensure the zero point of the Arduino reference system was set identically to that of the NDI optical positioning and tracking system, facilitating subsequent calculations.

[0037] Optionally, the displacement data of the passive marker ball is saved using NDI Track software.

[0038] Specifically, the measured displacement data is saved in the NDI Track software, recording the spatial coordinates and rotation information of the passive marker sphere, and finally exporting the dot matrix data in CSV format for later visualization.

[0039] Optionally, the optical positioning and tracking system can also perform planar accuracy calculations and coordinate accuracy calculations on the scalpel.

[0040] Specifically, the optical positioning and tracking system can also perform planar accuracy calculations on the scalpel. Connecting a PC to the optical positioning and tracking system, within the system's field of view, a 3D-printed guide plate is fixed to a vise. The scalpel tip is moved, and the NDI Track software's file save mode is opened to record the spatial coordinates and rotation information of the passive marker sphere, ultimately exporting CSV format dot matrix data. Under unchanged experimental conditions, the end effector of the cutting mechanism is moved multiple times at different speeds and directions, repeating the experiment to obtain multiple sets of data. Python is used to process the data. Since the data recorded by the NDI Track software includes the three-dimensional coordinates of all marker points and the quaternions of the single-sided marker rigid body, the data returned by the optical positioning and tracking system must first be filtered and preprocessed to obtain a CSV table containing only the relative three-dimensional coordinate information of the marker points and the origin of the reference coordinate system. To reconstruct the plane, the least squares method is used to find the best-fit function, resulting in the best-fit plane. After fitting the plane closest to the average distance of the dot matrix, the average and maximum distances between the dot matrix and the plane are calculated. Finally, the dot matrix and the fitted plane are plotted in space for visualization, and the average distance between the dot matrix and the fitted plane is calculated. This completes the planar accuracy calculation for the cutting robot. Based on the planar accuracy error, the drive structure between the three connecting parts and the connection structure between the scalpel and the third connecting part are adjusted and repaired.

[0041] The optical positioning and tracking system can also perform coordinate accuracy calculations on the scalpel. Under unchanged experimental conditions, the scalpel tip is moved multiple times at different speeds and directions, and the experiment is repeated to obtain multiple sets of data. Python is used to process the data. For the data recorded by the optical positioning and tracking system, it is first filtered and preprocessed to calculate the relative three-dimensional coordinates of the marker points to the origin of the reference coordinate system. Then, its distance from the origin is calculated. Additionally, the serial port data from the Arduino is processed. Since the z-axis distance in the Arduino coordinate system is known in advance, the distance between each point and the origin can be directly calculated. The origin of the NDI optical positioning and tracking system reference system and the origin of the Arduino reference system have been set to the same point in space. Therefore, by comparing the differences between the values ​​obtained from the two measurement methods, the coordinate calculation accuracy of this cutting robot system can be evaluated. Because the sampling frequencies of the two measurement methods are different, the time axis of the Arduino data needs to be stretched. The time axis is aligned, the difference of each point at the same time is calculated, and the average difference is calculated. This completes the coordinate accuracy calculation of the cutting robot. Based on the error value of the coordinate accuracy, the drive structure between the three connectors is adjusted and repaired, as is the connection structure between the scalpel and the third connector.

[0042] Optionally, the rotation axes of the first connector, the second connector, and the third connector are parallel to each other, and the rotation angle between the first connector, the second connector, the third connector, and the scalpel is controlled by a control unit.

[0043] Specifically, the cutting robot, through three hinged connectors and a control unit, can keep the movement of the scalpel on the same plane. The control unit can precisely control the rotation angle of the connectors, allowing the scalpel to reach any position in the preset cutting area to meet cutting requirements.

[0044] Optionally, a hinge structure for connecting the control unit is provided between the second connector and the third connector, the hinge structure including:

[0045] The connector has a first rotating motor at one end, and the output end of the first rotating motor is connected to the other end of the second connector.

[0046] The second rotating motor is located at the other end of the connecting base, and the output end of the second rotating motor is connected to one end of the third connecting piece.

[0047] Specifically, the transmission part located between the second and third connecting parts is a hinge structure. The hinge structure includes a first rotating motor, a second rotating motor, and a connecting seat. The two rotating parts are respectively located at both ends of the connecting seat, so that the second and third connecting parts can rotate relative to the hinge structure, thereby improving the movement efficiency of the scalpel.

[0048] Optionally, both the first and second rotary motors are dual-axis rotary motors.

[0049] Optionally, a single-axis servo motor connected to the control unit is provided between the first connector and the second connector, and between the third connector and the scalpel.

[0050] Specifically, depending on the structure of the three connecting parts, a dual-axis rotary motor or a single-axis servo motor is set between them. After the optical positioning and tracking system collects data from the scalpel and calculates the planar accuracy and coordinate accuracy, it can be quickly adjusted by the dual-axis rotary motor or the single-axis servo motor.

[0051] Optionally, the first connector and the 3D printing guide plate are connected by a quick-release pin, with one end of the first connector connected to the midpoint of the 3D printing guide plate.

[0052] Example

[0053] like Figure 1 As shown, the present invention provides a cutting robot with active precision constraint function, comprising:

[0054] The first connector 1 has one end for connecting to the 3D printing guide plate 4;

[0055] The second connector 2 is connected at one end to the other end of the first connector 1, and the other end of the second connector 2 is connected to the scalpel 5 through the third connector 3. The first connector 1, the second connector 2 and the third connector 3 are all connected by hinges.

[0056] The optical positioning and tracking system includes a marker rigid body and a passive marker ball. The marker rigid body is set on the 3D printed guide plate 4, and the passive marker ball is set at the end of the scalpel 5.

[0057] When the force gauge applies a pulling force to the end of the scalpel 5, the optical positioning and tracking system records the displacement of the passive marker ball. The multiple sets of displacement data recorded by the optical positioning and tracking system are used to adjust the scalpel 5.

[0058] In this embodiment, the optical positioning and tracking system uses a positioning tracker to obtain the position information of the passive marker ball.

[0059] In this embodiment, the marker rigid body is fixed to the 3D printed guide plate 4 by hot melt adhesive, and the passive marker ball is fixed to the end of the scalpel 5 by hot melt adhesive and bolt connection.

[0060] In this embodiment, the displacement data of the passive marker ball is saved using NDI Track software.

[0061] In this embodiment, the optical positioning and tracking system can also perform planar accuracy calculations and coordinate accuracy calculations on the scalpel.

[0062] In this embodiment, the rotation axes of the first connector 1, the second connector 2, and the third connector 3 are parallel to each other, and the rotation angle between the first connector 1, the second connector 2, the third connector 3, and the scalpel 5 is controlled by a control unit.

[0063] In this embodiment, a hinge structure for connecting the second connector 2 and the third connector 3 to the control unit is provided. The hinge structure includes:

[0064] The connecting base 6 has a first rotating motor 7 at one end, and the output end of the first rotating motor 7 is connected to the other end of the second connecting piece 2.

[0065] The second rotating motor is located at the other end of the connecting seat 6, and the output end of the second rotating motor is connected to one end of the third connecting piece 3.

[0066] In this embodiment, both the first rotating motor 7 and the second rotating motor are dual-axis rotating motors.

[0067] In this embodiment, a single-axis servo motor 9 connected to the control unit is respectively provided between the first connector 1 and the second connector 2 and the third connector 3 and the scalpel 5.

[0068] In this embodiment, the first connector 1 and the 3D printing guide plate 4 are connected by a quick-release pin 8, and one end of the first connector 1 is connected to the midpoint of the 3D printing guide plate 4.

[0069] In summary, this cutting robot with active precision constraint function can be divided into two parts: a relatively stationary part relative to the knee and a non-relatively stationary part. The 3D-printed guide plate serves as the relatively stationary part, and the marker rigid body is bonded to the 3D-printed guide plate. The scalpel tip serves as the non-relatively stationary part, and a passive marker ball is bonded to the scalpel tip. The marker rigid body serves as the coordinate zero point in the measurement system. In the Arduino control program, correction factors are added to the x-axis and y-axis respectively, and the coordinate zero point of the Arduino reference system is set to be the same as that of the NDI system for subsequent calculations. When applying active precision constraint to the scalpel tip, a force gauge is connected to the scalpel tip to monitor the torque applied to the scalpel tip. The optical positioning and tracking system monitors the displacement distance of the scalpel tip. When the displacement distance exceeds a set threshold, the torque displayed by the force gauge is recorded. This test is repeated multiple times, and the measured data is processed using Python to calculate the distance of deviation relative to the coordinate origin, thus adjusting the cutting robot accordingly.

[0070] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A cutting robot with active precision constraint function, characterized in that, include: The first connector has one end for connecting to the 3D printing guide plate; The second connector has one end connected to the other end of the first connector, and the other end of the second connector is connected to the scalpel through the third connector. The first connector, the second connector and the third connector are all connected by hinges. An optical positioning and tracking system includes a marker rigid body and a passive marker ball, wherein the marker rigid body is disposed on the 3D printed guide plate and the passive marker ball is disposed at the end of the scalpel; When the force gauge applies a pulling force to the end of the scalpel, the optical positioning and tracking system records the displacement of the passive marker ball. The multiple sets of displacement data recorded by the optical positioning and tracking system are used to adjust the scalpel. The rotation axes of the first connector, the second connector, and the third connector are parallel to each other, and the rotation angle between the first connector, the second connector, the third connector, and the scalpel is controlled by a control unit. A hinge structure for connecting the control unit is provided between the second connector and the third connector, the hinge structure comprising: A connector is provided with a first rotating motor at one end, and the output end of the first rotating motor is connected to the other end of the second connector. A second rotating motor is located at the other end of the connecting base, and the output end of the second rotating motor is connected to one end of the third connecting member.

2. The cutting robot with active precision constraint function according to claim 1, characterized in that, The optical positioning and tracking system uses a positioning tracker to obtain the position information of the passive marker ball.

3. The cutting robot with active precision constraint function according to claim 1, characterized in that, The marker rigid body is connected to the 3D printed guide plate by hot melt adhesive, and the passive marker ball is connected to the end of the scalpel by hot melt adhesive and bolts.

4. The cutting robot with active precision constraint function according to claim 1, characterized in that, The displacement data of the passive marker ball is saved using NDI Track software.

5. The cutting robot with active precision constraint function according to claim 1, characterized in that, The optical positioning and tracking system can also perform planar accuracy calculations and coordinate accuracy calculations on the scalpel.

6. The cutting robot with active precision constraint function according to claim 1, characterized in that, Both the first rotating motor and the second rotating motor are dual-axis rotating motors.

7. The cutting robot with active precision constraint function according to claim 1, characterized in that, A single-axis servo motor connected to the control unit is respectively provided between the first connector and the second connector, and between the third connector and the scalpel.

8. The cutting robot with active precision constraint function according to claim 1, characterized in that, The first connector and the 3D printing guide plate are connected by a quick-release pin, and one end of the first connector is connected to the midpoint of the 3D printing guide plate.

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