A contactless surgical robot system based on whole-body magnetic levitation joints

Abstract

The application discloses a kind of contactless surgical robot systems based on whole body magnetic suspension joint, belong to medical robot technical field.The application includes at least one mechanical arm, multiple magnetic suspension joints, at least one end effector and control system, mechanical arm is connected by magnetic suspension joint in turn by multiple arm sections, magnetic suspension joint includes first joint piece, second joint piece, permanent magnet array and electromagnetic coil, adjacent arm section is fixedly connected with two joint pieces respectively, realizes contactless swing transmission and stiffness stepless continuous regulation by magnetic field force;Control system is according to end effector target motion track, solves each joint target swing angle and target stiffness and drives joint action, simultaneously by distributed sensing system real-time acquisition position, force and temperature data, completes motion closed-loop control.The application eliminates the transmission backlash and mechanical wear of traditional surgical robot, fundamentally eliminates the risk of surgical infection caused by wear debris of kinematic pair, transmission precision and force control safety are significantly improved, suitable for neurosurgery, ophthalmology, cardiovascular and other various high-precision minimally invasive surgery.

Description

Technical Field

[0001] This invention belongs to the field of medical robot technology, specifically relating to a non-contact surgical robot system based on whole-body magnetic levitation joints, which is particularly suitable for minimally invasive surgical scenarios such as neurosurgery, ophthalmology, and cardiovascular surgery, where positioning accuracy and force control safety are extremely important. Background Technology

[0002] Currently, most surgical robots used in clinical practice employ a transmission structure consisting of a motor paired with a reducer and cable drive. This type of structure has the following inherent drawbacks: First, the inherent transmission backlash in mechanical transmission components such as gears, bearings, and tendon cables limits the positioning accuracy of the end effector, making it difficult to meet the sub-millimeter positioning requirements of high-precision minimally invasive surgery; Second, mechanical kinematic pairs will experience friction and wear during long-term reciprocating motion, and the resulting tiny debris may fall into the surgical area, posing a risk of surgical infection; Third, the structural stiffness of traditional mechanical joints is a fixed value and cannot be dynamically adjusted according to different stages of the surgical procedure, resulting in insufficient force control precision and a high risk of accidental injury when contacting fragile human tissues; Fourth, mechanical transmission components require regular lubrication and maintenance, leading to high equipment maintenance frequency and operating costs. Summary of the Invention

[0003] The purpose of this invention is to overcome the technical defects of existing surgical robots, such as large transmission backlash, easy generation of wear debris, fixed and unadjustable joint stiffness, and high maintenance costs, and to provide a non-contact surgical robot system based on whole-body magnetic levitation joints.

[0004] The core concept of this invention is to completely replace traditional mechanical joints with magnetically levitated joints, achieving fully contactless transmission of the surgical robot arm. The magnetically levitated joint employs a composite structure of a permanent magnet array and an electromagnetic coil. The permanent magnet array provides a basic magnetic field to keep the joint components levitated and separated, while the electromagnetic coil adjusts the magnetic field strength and distribution by changing the applied current, achieving both contactless swing transmission of the joint and stepless continuous adjustment of joint stiffness. Furthermore, a distributed sensing system is pre-embedded within the robotic arm and end effector to collect multi-dimensional data such as force, temperature, and position in real time. This data is fed back to the control system to form a fully closed-loop motion control system. A safety protection module is also included, which immediately cuts off the current and locks the joint upon detecting an anomaly, ensuring the safety of the surgical procedure.

[0005] The technical solution of this invention is as follows: A contactless surgical robot system based on whole-body magnetic levitation joints, comprising at least one robotic arm, multiple magnetic levitation joints, at least one end effector, a control system, and a distributed sensing system. The robotic arm is composed of multiple arm segments connected sequentially, and each magnetic levitation joint is positioned between any two adjacent arm segments and between an arm segment and the end effector. Each magnetic levitation joint includes a first joint component, a second joint component, at least two sets of opposing permanent magnet arrays, and at least one pair of symmetrically arranged electromagnetic coils. The first and second joint components are arranged opposite each other with a levitation gap of 0.5mm to 2mm between their end faces, without any physical contact. The permanent magnet arrays are respectively fixed to the opposite surfaces of the two joint components. The electromagnetic coils are symmetrically installed on the sides of the first joint component, and adjacent arm segments are fixedly connected to the first and second joint components, respectively. The control system is electrically connected to the electromagnetic coils and end effector of all magnetic levitation joints, and is used to calculate the target swing angle and target stiffness of each magnetic levitation joint according to surgical operation instructions, generate drive signals, and output them to each electromagnetic coil. The distributed sensing system is embedded in the robotic arm segment and end effector to collect data on force, temperature and joint swing angle in real time, and feed it back to the control system to form a motion closed-loop control.

[0006] Compared with the prior art, the present invention has the following significant advantages: Zero backlash and zero wear: The magnetic levitation joint has no mechanical contact throughout the entire process, eliminating transmission backlash and mechanical wear at the source. The positioning accuracy of the end effector can reach the sub-millimeter level, and no wear debris is generated, eliminating the risk of surgical infection. Infinitely adjustable stiffness: By continuously adjusting the electromagnetic coil current, the joint stiffness can be infinitely varied across the entire working condition range, providing stable support during the positioning phase that requires high stiffness and providing compliant force control during the tissue contact phase that requires low stiffness, thus greatly improving surgical safety. Full closed-loop safety protection: The distributed sensing system monitors the force, temperature and posture data of the robotic arm in real time. When the control system detects an anomaly, it can cut off the current and lock the joint within milliseconds to achieve active safety protection. Low maintenance costs: With no mechanical transmission parts, there is no need for regular lubrication or replacement of wear parts, significantly reducing the maintenance costs throughout the equipment's life cycle. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of the robotic arm structure of the non-contact surgical robot system based on whole-body magnetic levitation joints of the present invention.

[0008] Figure 2 This is an enlarged structural schematic diagram of the magnetic levitation joint of the present invention.

[0009] Explanation of markings in the diagram: 1-robotic arm base, 2-first arm segment, 3-first magnetic levitation joint, 4-second arm segment, 5-second magnetic levitation joint, 6-end effector; 31-First joint component, 32-Second joint component, 33-Permanent magnet array, 34-Electromagnetic coil. Detailed Implementation

[0010] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings. These embodiments are only used to explain the present invention and are not intended to limit the scope of protection of the present invention.

[0011] This embodiment is a multi-degree-of-freedom surgical robotic arm system. The robotic arm is composed of a robotic arm base 1, a first arm segment 2, a first magnetic levitation joint 3, a second arm segment 4, a second magnetic levitation joint 5, and an end effector 6 connected sequentially from bottom to top.

[0012] Each magnetic levitation joint employs a micro-oscillating magnetic levitation joint structure with infinitely adjustable stiffness. For example... Figure 2 As shown, the magnetic levitation joint includes a first joint component 31, a second joint component 32, two sets of opposing permanent magnet arrays 33, and a pair of symmetrically arranged electromagnetic coils 34. The first joint component 31 and the second joint component 32 are made of medical-grade engineering plastic, arranged opposite each other with a 1mm levitation gap between their end faces, ensuring no mechanical contact throughout the entire process. The two sets of permanent magnet arrays 33 are respectively fixedly installed on the opposite end faces of the first joint component 31 and the second joint component 32, forming a basic magnetic field generating unit. The two electromagnetic coils 34 are symmetrically installed on the side of the first joint component 31, forming a coupled magnetic field with the permanent magnet arrays 33.

[0013] Adjacent arm segments are fixedly connected to the first joint member 31 and the second joint member 32 respectively using medical-grade bolts. The permanent magnet array 33 generates a constant basic magnetic field, and the coupling effect of magnetic repulsion and magnetic attraction keeps the first joint member 31 and the second joint member 32 in a suspended and separated state. When the control system changes the magnitude of the working current supplied to the electromagnetic coil 34, the overall strength and distribution of the coupled magnetic field change accordingly, and the swing resistance and restoring force of the joint change synchronously, thereby realizing stepless continuous adjustment of the joint stiffness.

[0014] In this embodiment, the maximum swing angle of the magnetic levitation joint is ±90°, the positioning accuracy can reach 0.1mm, the stiffness adjustment range is 0.1N·m / rad to 100N·m / rad, and the response time is less than 1ms.

[0015] The distributed sensing system uses a fiber Bragg grating sensor array embedded in the carbon fiber shell interlayer of each arm segment. It can simultaneously detect the force, temperature and deformation data of each arm segment and feed the data back to the control system in real time.

[0016] During operation, the main control equipment issues surgical operation instructions. The control system obtains the target swing angle sequence and target stiffness sequence of the first magnetic levitation joint 3 and the second magnetic levitation joint 5 through inverse kinematics calculation based on the target motion trajectory of the end effector 6. It generates the corresponding electromagnetic coil drive current signal and outputs it to drive the joints to move, so that the end effector 6 runs along the target trajectory.

[0017] The distributed sensing system collects and feeds back real-time data on actual force, temperature, and swing angle at each location. The control system compares the actual data with preset safety thresholds: when the data is within the safe range, it dynamically corrects the drive current signals of each electromagnetic coil based on the deviation between the actual swing angle and the target swing angle, achieving closed-loop motion control; when any data exceeds the safety threshold, the safety protection module in the control system immediately cuts off the output current of all electromagnetic coils, and each joint returns to its zero position and locks under the action of the permanent magnet base magnetic field. The trigger response time of the safety protection module is less than 5ms, and a fault signal is reported to the main control device, achieving active safety protection.

[0018] The control method of the present invention specifically includes the following steps: S1: The control system receives surgical operation instructions and sets the target motion trajectory of the end effector 6; S2: Based on the target motion trajectory, the target swing angle sequence and target stiffness sequence of the first magnetic levitation joint 3 and the second magnetic levitation joint 5 are obtained through inverse kinematics calculation; S3: Generate the driving current signal of each magnetic levitation joint electromagnetic coil 34 according to the target swing angle sequence and the target stiffness sequence; S4: Output drive current signals to each electromagnetic coil 34 to drive each magnetic levitation joint to move, so that the end effector 6 runs along the target motion trajectory; S5: The distributed sensing system collects real-time data on the actual force, temperature, and swing angle of the robotic arm at various positions and feeds it back to the control system. S6: The control system compares the actual force data, actual temperature data, and actual swing angle data with the preset safety threshold. When any data exceeds the corresponding safety threshold, the safety protection module is triggered to perform shutdown protection. When the data is within the safe range, the drive current signal of each electromagnetic coil 34 is dynamically corrected according to the deviation between the actual swing angle and the target swing angle to complete the motion closed-loop control.

[0019] This invention is applicable to various high-precision minimally invasive surgeries such as neurosurgery, ophthalmology, and cardiovascular surgery.

Claims

1. A contactless surgical robot system based on whole-body magnetic levitation joints, characterized in that, include: At least one robotic arm, which is composed of multiple arm segments connected in sequence; Multiple magnetic levitation joints are provided, each of which is disposed between any two adjacent arm segments and between an arm segment and an end effector. Each magnetic levitation joint includes a first joint component, a second joint component, at least two sets of opposing permanent magnet arrays, and at least one pair of symmetrically arranged electromagnetic coils. The first joint component and the second joint component are arranged opposite each other with a levitation gap of 0.5 mm to 2 mm reserved between their end faces, without any physical contact. The permanent magnet arrays are respectively fixed on the opposite surfaces of the first joint component and the second joint component. The electromagnetic coils are symmetrically installed on the side of the first joint component. Adjacent arm segments are respectively fixedly connected to the first joint component and the second joint component. The permanent magnet arrays form a basic magnetic field to keep the two joint components in a levitation state. By changing the current flowing through the electromagnetic coils, the magnetic field strength and distribution can be adjusted to achieve contactless swing transmission and stepless continuous adjustment of stiffness of the joint. At least one end effector is attached to the end of the robotic arm; The control system is electrically connected to the electromagnetic coils and end effectors of all magnetic levitation joints, and is used to calculate the target swing angle and target stiffness of each magnetic levitation joint according to the surgical operation instructions, generate drive signals and output them to each electromagnetic coil. The distributed sensing system includes sensing units embedded in the robotic arm segment and end effector, which are used to collect force data, temperature data and joint swing angle data at various positions of the robotic arm in real time, and feed them back to the control system to form a motion closed-loop control.

2. The system according to claim 1, characterized in that, The distributed sensing system employs a fiber Bragg grating sensor, which is embedded in the carbon fiber shell interlayer of the arm segment.

3. The system according to claim 1, characterized in that, The control system has a built-in safety protection module. When the distributed sensing system detects that the force on the robotic arm exceeds the preset safety threshold, the joint swing angle exceeds the preset stroke range, or the suspension gap deviates abnormally, the safety protection module immediately cuts off the output current of each electromagnetic coil, so that each magnetic levitation joint returns to the zero position and locks under the action of the permanent magnet base magnetic field.

4. A control method based on the system according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1: The control system receives surgical operation instructions and sets the target motion trajectory of the end effector; S2: Based on the target motion trajectory, the target swing angle sequence and target stiffness sequence of each magnetic levitation joint are obtained through inverse kinematics calculation; S3: Generate the driving current signal of each magnetic levitation joint electromagnetic coil according to the target swing angle sequence and the target stiffness sequence; S4: Output the driving current signal to each electromagnetic coil to drive each magnetic levitation joint to move, so that the end effector runs along the target motion trajectory; S5: The distributed sensing system collects real-time data on the actual force, temperature, and swing angle of the robotic arm at various positions and feeds it back to the control system. S6: The control system compares the actual force data, actual temperature data, and actual swing angle data with the preset safety threshold. When any data exceeds the corresponding safety threshold, the safety protection module is triggered to perform shutdown protection. When the data is within the safe range, the drive current signal of each electromagnetic coil is dynamically corrected according to the deviation between the actual swing angle and the target swing angle to complete the motion closed-loop control.

5. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the control method of claim 4.

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