Long bone fracture robot

Abstract

This invention discloses a long bone fracture robot, relating to the field of medical robot technology. The robot includes an upper fixation ring, a lower fixation ring, and six sets of sliding components connected between them. These six sets of sliding components are spatially distributed and form a parallel mechanism. Each sliding component includes a lead screw assembly and a drive assembly. The lead screw assembly includes a lead screw and at least one U-shaped joint, with the U-shaped joint connecting the end of the lead screw to the corresponding fixation ring. The two rotation axes of the U-shaped joint maintain a non-compatibility distribution structure with a preset distance in space to increase the joint's swing angle range and improve multi-directional load-bearing capacity. The drive assembly converts the rotational motion of the motor into the linear motion of the lead screw through gear transmission, realizing the extension and retraction of the sliding components. This invention can avoid unusual configurations within a larger workspace, providing safer, more precise, and more efficient assistance in fracture reduction surgery.

Description

Technical Field

[0001] This invention relates to the field of medical robot technology, specifically to a long bone fracture robot. Background Technology

[0002] Long bone fractures are common orthopedic injuries. Traditional closed reduction surgery relies heavily on the surgeon's clinical experience and requires continuous X-ray fluoroscopy, which leads to problems such as high radiation exposure, unstable reduction accuracy, and a high risk of secondary soft tissue injury. With the development of medical robotics technology, robot-assisted fracture reduction technology has gradually become a research hotspot. It achieves precise reduction through automated control, effectively reducing iatrogenic injury and intraoperative radiation.

[0003] Existing fracture reduction robots mostly employ serial or traditional parallel mechanisms. Serial mechanisms offer a large workspace but suffer from low stiffness and poor precision; while traditional parallel mechanisms, although possessing high stiffness and precision, have limited joint range of motion and are prone to unusual configurations, leading to loss of control during surgery. Furthermore, the traditional cruciate U-shaped joint lacks sufficient load-bearing capacity and mobility to meet the demands of multi-directional forces and wide-range movements required for complex fracture reduction. Therefore, there is an urgent need to develop a long bone fracture robot that combines high stiffness, high precision, a large workspace, and high safety. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a long bone fracture robot. Through an innovative non-common U-shaped joint design and a six-degree-of-freedom redundant parallel structure, it effectively expands the workspace, enhances the ability to avoid singular configurations, and improves structural rigidity and motion flexibility, thereby assisting in the completion of fracture reduction surgery more safely, accurately, and efficiently.

[0005] To solve the above problems, the technical solution provided by the present invention is as follows:

[0006] A long bone fracture robot, comprising:

[0007] Upper fixing ring;

[0008] Lower fixing ring;

[0009] And six sets of sliding components are connected between the upper fixed ring and the lower fixed ring. The six sets of sliding components are distributed around the space and together form a parallel mechanism, so that the upper fixed ring can achieve six degrees of freedom of spatial motion relative to the lower fixed ring. Each set of sliding components includes a lead screw assembly and a drive assembly. The lead screw assembly includes a lead screw and at least one U-shaped joint. The U-shaped joint is connected between the end of the lead screw and the corresponding fixed ring. The two rotation axes of the U-shaped joint maintain a non-coordinated distribution structure with a preset distance in space.

[0010] Upper and lower fixation rings: These fix the proximal and distal bone segments of the fracture, respectively, providing a stable mechanical support for the reduction operation.

[0011] The parallel mechanism consisting of six sets of sliding components enables six degrees of freedom of spatial movement of the upper fixation ring relative to the lower fixation ring, covering all actions required for fracture reduction, including axial traction, spatial rotation, and alignment of fracture ends. The parallel mechanism naturally possesses high rigidity, high precision, and high load-bearing characteristics, and can withstand large forces during the reduction process.

[0012] U-shaped joint: Enables relative rotation between the sliding component and the fixed ring, compensating for angular deviations under different reset postures.

[0013] The U-shaped joint non-common distribution structure is a core innovation that eliminates the interference problem of traditional cross-axis joints, increasing the joint swing angle range from ±30° to over ±45°; it optimizes the force distribution and improves the multi-directional load-bearing capacity; and in conjunction with the six-branch redundant drive, it significantly expands the safe working space, effectively avoids singular configurations, and prevents loss of control of movement during surgery.

[0014] Optionally, the lead screw assembly includes a first U-shaped joint and a second U-shaped joint, the first U-shaped joint being connected to the upper fixed ring, and the second U-shaped joint being connected to one end of the lead screw; the drive assembly includes a gear housing, a motor, a driving gear, a driven gear, a sleeve, and a third U-shaped joint; the motor is fixedly mounted on the gear housing, and its output shaft is connected to the driving gear; the driven gear is rotatably disposed within the gear housing and meshes with the driving gear, and the driven gear has an internal thread at its center that engages with the external thread of the lead screw; the sleeve is fixedly connected to the gear housing, and the third U-shaped joint is connected between the sleeve and the lower fixed ring; the two rotation axes of the first U-shaped joint, the second U-shaped joint, and the third U-shaped joint all adopt a non-common point distribution structure.

[0015] The first U-shaped joint, the second U-shaped joint, and the third U-shaped joint form three levels of rotational compensation at both ends and in the middle of the sliding component, further expanding the robot's posture adjustment range and adapting to the reduction requirements of complex fractures.

[0016] The motor, drive gear, and driven gear form a reduction transmission pair, which converts the high-speed, low-torque motion of the motor into low-speed, high-torque motion to meet the high load requirements of fracture reduction.

[0017] The driven gear's internal thread engages with the lead screw's external thread, precisely converting rotary motion into linear motion to achieve the extension and retraction drive of the sliding component.

[0018] Sleeve: Provides axial guidance for the lead screw, preventing it from bending and deforming; at the same time, it protects the internal transmission mechanism from contamination and mechanical damage.

[0019] Fully articulated, non-common-point design: comprehensively enhances the movement flexibility and load-bearing capacity of the mechanism, ensuring the smooth movement of the entire parallel system within a large workspace.

[0020] Optionally, the driven gear is rotatably supported within the gear housing by bearing one and bearing two to ensure rotational accuracy and smooth operation; the driving gear is made of self-lubricating material and requires no additional bearing support; the motor is fixed within the motor housing, and the motor housing is fixed to the gear housing by set screws; the sleeve is fixed to the end of the gear housing by screws and / or set screws.

[0021] Bearing 1 and Bearing 2: Support the driven gear, ensure its rotational accuracy and smooth operation, reduce frictional loss, and improve transmission efficiency.

[0022] Self-lubricating drive gears: No need to add extra lubricating oil, avoiding contamination of the surgical environment; reduce the friction coefficient between gears, extend service life, and reduce maintenance needs.

[0023] Motor housing: Protects the motor from mechanical damage and contamination, while providing a heat dissipation channel.

[0024] Set screws secure the motor housing: ensure the meshing accuracy of the drive gear and driven gear, and prevent transmission backlash.

[0025] Double fixing sleeve with screw and set screw: improves connection reliability and prevents the sleeve from loosening or falling off under force.

[0026] Optionally, the first U-shaped joint is connected to one end of the lead screw via a threaded connection and is provided with a set screw for circumferential locking; the second U-shaped joint is also connected to the other end of the lead screw via a threaded connection and is provided with a set screw; the connection between the third U-shaped joint and the sleeve is also provided with a set screw locking structure.

[0027] Threaded connection: Enables detachable connection between the U-shaped joint and the lead screw, and between the third U-shaped joint and the sleeve, facilitating assembly, debugging, and component replacement.

[0028] Circumferential locking of set screws: Prevents threaded connections from loosening under alternating loads, ensuring transmission accuracy and connection reliability, and avoiding reset errors caused by loose connections.

[0029] Optionally, a control system is also included, comprising: a main control unit; six motor drivers, each electrically connected to the main control unit and the motors in the six sets of sliding components, for independently driving each motor; multiple sensors, electrically connected to the main control unit, for detecting the displacement of each sliding component or the rotation angle of the motor; a signal buffer isolation module, connected between the main control unit and the motor drivers, for enhancing the driving capability of the driving signal and isolating electrical interference; a power management module, for converting externally input DC power into multiple DC power supplies of different voltages, for powering the main control unit, motor drivers, and sensors respectively; and a communication interface for exchanging data with an external host computer or surgical navigation system.

[0030] Main control unit: The core of the robot's control, responsible for kinematic calculation, control command generation, data processing and fault diagnosis, and realizing the coordinated control of the six sliding components.

[0031] Six independent motor drivers: drive six sets of motors respectively to achieve independent control of six degrees of freedom, ensuring that the robot can complete any complex spatial movement.

[0032] Sensors: detect the displacement of the sliding component or the speed of the motor, provide feedback signals for closed-loop control, and improve reset accuracy and motion stability.

[0033] Signal buffer isolation module: Enhances the driving capability of the main control unit's output signal, enabling it to drive multiple motor drivers; at the same time, it isolates electrical interference and protects the main control unit from high-voltage surges.

[0034] Power management module: Converts a single external power supply into multiple stable power supplies to meet the power supply requirements of various components of the control system and ensure stable system operation.

[0035] Communication interface: Enables data exchange between the robot and the host computer and surgical navigation system, receives reset trajectory commands, and uploads operating status and fault information.

[0036] Optionally, the motor driver is an integrated H-bridge driver chip with PWM speed regulation, direction control, enable control, fault detection and current detection functions; the current detection pin of the driver chip is connected to ground through a sampling resistor, which is connected to the ADC input terminal of the main control unit to realize current closed-loop control or overcurrent protection.

[0037] Integrated H-bridge driver chip: high integration, simple peripheral circuit, and high reliability; realizes motor forward and reverse rotation, PWM speed regulation and enable control, meeting motion control requirements.

[0038] Fault detection function: Real-time detection of faults such as overcurrent, overheating, and undervoltage. When a fault occurs, a signal is immediately output to notify the main control unit to take protective measures.

[0039] Current detection function: Real-time monitoring of motor operating current enables closed-loop current control and improves torque control accuracy; it also provides overcurrent protection to prevent motor and driver burnout.

[0040] The sampling resistor is connected to the ADC: it converts the current signal into a voltage signal for the main control unit to digitally sample and process.

[0041] Optionally, the signal buffer isolation module includes at least one bidirectional buffer chip, the input of which is connected to the main control unit and the output of which is connected to the motor driver; the operating voltage of the bidirectional buffer chip is compatible with the logic voltage of the main control unit.

[0042] Bidirectional buffer chip: enhances signal driving capability and extends transmission distance; achieves electrical isolation between the main control unit and the motor driver, and protects the I / O pins of the main control unit.

[0043] Logic voltage compatibility: Ensures accurate signal transmission and avoids signal distortion and malfunctions caused by level mismatch.

[0044] Optionally, the power management module includes: a first-stage DC-DC step-down circuit to step down the input high-voltage DC power to a first intermediate voltage; at least one second-stage LDO voltage regulator circuit to further step down the first intermediate voltage to a stable logic voltage to power the main control unit and sensors; and a motor power supply branch to supply the input high-voltage DC power directly or after filtering to the motor driver.

[0045] The first-stage DC-DC step-down circuit efficiently converts high-voltage DC power into an intermediate voltage with high conversion efficiency and low heat generation, providing a foundation for powering subsequent circuits and motors.

[0046] Two-stage LDO voltage regulator circuit: low output ripple and low noise, providing a stable logic power supply for main control units and sensors with high power quality requirements.

[0047] Motor power supply branch: directly provides high voltage and high current power to the motor driver to meet the power requirements of the motor; after filtering, the impact of power supply ripple on motor operation can be reduced.

[0048] Optionally, the sensor includes an encoder mounted on the motor, or a linear displacement sensor mounted on the sliding assembly; the communication interface is at least one of a CAN bus interface, an RS interface, an Ethernet interface, or a wireless communication module.

[0049] Motor-side encoder: Indirectly detects the displacement of the sliding component to achieve closed-loop position control; it has high accuracy, fast response, high reliability, and low cost.

[0050] Linear displacement sensor: directly detects the actual displacement of the sliding component, eliminating transmission backlash and errors, and achieving higher measurement accuracy.

[0051] Multiple communication interfaces: providing flexible connection methods to adapt to different surgical environments and equipment requirements; CAN bus has strong anti-interference capabilities, suitable for operating rooms; Ethernet has fast transmission speed, suitable for large data transmission.

[0052] Optionally, both the upper and lower fixing rings are provided with six connecting holes for fixed connection to the two ends of the six sets of sliding components by fasteners; at least a portion of the upper fixing ring, lower fixing ring and sliding components are made of lightweight alloy or carbon fiber composite material.

[0053] Six evenly distributed connecting holes: ensure that the force of the six sets of sliding components is evenly distributed on the fixed ring, avoiding deformation of the fixed ring; ensure the kinematic symmetry of the parallel mechanism and improve motion accuracy.

[0054] Lightweight alloys or carbon fiber composites: While ensuring structural strength and rigidity, they significantly reduce the weight of the robot, facilitating intraoperative operation and handling; they also have good biocompatibility and corrosion resistance.

[0055] Compared with the prior art, the technical solution provided by this invention has the following advantages:

[0056] Excellent motion performance: The non-common U-shaped joint design increases the range of joint swing angles. Combined with a six-degree-of-freedom redundant parallel structure, the robot can achieve a wide range of high-precision six-degree-of-freedom spatial motion, meeting the needs of complex movements during fracture reduction.

[0057] High safety: Redundant drive characteristics enable the robot to avoid singular configurations in a larger workspace and avoid loss of motion control; the non-common joint design improves multi-directional load-bearing capacity, reduces soft tissue stress concentration, and reduces the risk of secondary injury.

[0058] High precision: It adopts a high-precision transmission method of "motor-gear-lead screw", combined with bearing support and closed-loop control, to achieve micron-level linear displacement output, ensuring the accuracy of the reset action.

[0059] Compact and reliable structure: The drive components are highly integrated and the connections between the parts are firm; the use of self-lubricating gears and bearings reduces maintenance requirements and improves overall reliability.

[0060] Lightweight design: Key components are made of lightweight alloys or carbon fiber composites, which reduces the weight of the robot and facilitates intraoperative operation and handling. Attached Figure Description

[0061] Figure 1This is a schematic diagram of the overall structure of a long bone fracture robot proposed in an embodiment of the present invention;

[0062] Figure 2 A schematic diagram of the overall structure of a sliding component of a long bone fracture robot proposed in an embodiment of the present invention;

[0063] Figure 3 An exploded structural diagram of a double U-shaped joint of a long bone fracture robot proposed in an embodiment of the present invention;

[0064] Figure 4 An exploded structural diagram of a drive assembly for a long bone fracture robot according to an embodiment of the present invention;

[0065] Figure 5 A block diagram of a control system for a long bone fracture robot proposed as an embodiment of the present invention;

[0066] Figure 6 A schematic diagram of a motor drive circuit corresponding to a set of sliding components of a long bone fracture robot proposed in an embodiment of the present invention;

[0067] Figure 7 A schematic diagram of a signal buffer circuit for a long bone fracture robot proposed in an embodiment of the present invention;

[0068] 1. Upper fixing ring; 2. Sliding assembly; 3. Lower fixing ring; 4. First U-shaped joint; 5. Shaft; 6. Double-shaft joint; 7. Second U-shaped joint; 8. Gear cover; 9. Bearing 1; 10. Driven gear; 11. Bearing 2; 12. Gear housing; 13. Sleeve; 14. Drive gear; 15. Motor housing; 16. Motor. Detailed Implementation

[0069] To further understand the content of this invention, a detailed description of the invention will be provided in conjunction with the accompanying drawings and embodiments.

[0070] Example 1

[0071] Combined with appendix Figure 1 A long bone fracture robot, comprising:

[0072] Upper fixing ring 1;

[0073] Lower fixing ring 3;

[0074] And six sets of sliding components 2, connected between the upper fixed ring 1 and the lower fixed ring 3, the six sets of sliding components 2 are distributed around the space and together form a parallel mechanism, so that the upper fixed ring 1 can achieve six degrees of freedom of spatial motion relative to the lower fixed ring 3; wherein, each set of sliding components 2 includes a lead screw assembly and a drive assembly, the lead screw assembly includes a lead screw and at least one U-shaped joint, the U-shaped joint is connected between the end of the lead screw and the corresponding fixed ring; the two rotation axes 5 of the U-shaped joint maintain a non-co-point distribution structure with a preset distance in space, so as to increase the joint swing angle range and improve the multi-directional load-bearing capacity.

[0075] The parallel mechanism connects the upper and lower platforms via six independent telescopic chains. According to the Stewart platform kinematics principle, the combination of the lengths of the six chains uniquely determines the six-degree-of-freedom pose of the upper platform relative to the lower platform. Six sets of sliding components 2 are evenly distributed in space, with their ends fixed to the connecting holes of the upper fixation ring 1 and the lower fixation ring 3 respectively via bolts, together forming a six-degree-of-freedom parallel mechanism. The upper fixation ring 1 is used to fix the proximal bone segment of the fracture, and the lower fixation ring 3 is used to fix the distal bone segment. Through the independent extension and retraction of the six sets of sliding components 2, the upper fixation ring 1 achieves six-degree-of-freedom spatial movement relative to the lower fixation ring 3, thereby completing the fracture reduction.

[0076] The two rotation axes of the non-concurrent U-shaped joint have a preset distance in space, rather than intersecting at a single point, which eliminates mechanical interference between the axes and allows the joint to rotate within a larger angle; at the same time, it disperses the force on the joint and avoids stress concentration.

[0077] When the six sliding components 2 extend and retract independently, the upper fixing ring 1 completes spatial movement according to the preset trajectory through the rotation compensation of the U-shaped joint, thereby achieving precise reduction of the fracture ends.

[0078] Both the upper fixing ring 1 and the lower fixing ring 3 are provided with six connecting holes for fixing to the two ends of the six sets of sliding components 2 respectively by fasteners; at least a part of the upper fixing ring 1, the lower fixing ring 3 and the sliding components 2 are made of lightweight alloy or carbon fiber composite material.

[0079] The six connecting holes are evenly distributed in a regular hexagon on the fixed ring, so that the support forces of the six sets of sliding components 2 act symmetrically on the fixed ring, resulting in uniform force and structural stability.

[0080] Lightweight alloys such as aluminum alloys and titanium alloys, as well as carbon fiber composite materials, have the characteristics of high strength and low density. Using them to manufacture key components can significantly reduce the weight of robots and improve portability and operability.

[0081] like Figure 2As shown, the lead screw assembly includes a first U-shaped joint 4 and a second U-shaped joint 7. The first U-shaped joint 4 is connected to the upper fixed ring 1, and the second U-shaped joint 7 is connected to one end of the lead screw. The drive assembly includes a gear housing 12, a motor 16, a driving gear 14, a driven gear 10, a sleeve 13, and a third U-shaped joint. The motor 16 is fixed on the gear housing 12, and its output shaft 5 is connected to the driving gear 14. The driven gear 10 is rotatably disposed in the gear housing 12 and meshes with the driving gear 14. The driven gear 10 has an internal thread at its center, which engages with the external thread of the lead screw. The sleeve 13 is fixedly connected to the gear housing 12, and the third U-shaped joint is connected between the sleeve 13 and the lower fixed ring 3. The two rotating shafts 5 of the first U-shaped joint 4, the second U-shaped joint 7, and the third U-shaped joint all adopt a non-common distribution structure.

[0082] The motor 16 outputs high-speed rotation, which is reduced in speed after meshing with the drive gear 14 and driven gear 10, driving the driven gear 10 to rotate at low speed.

[0083] The driven gear 10 is axially limited by the bearing, and its rotational motion is converted into the axial linear motion of the lead screw through the helical transmission pair, causing the lead screw to extend or retract relative to the drive assembly.

[0084] The three U-shaped joints provide two orthogonal rotational degrees of freedom. When the sliding component 2 extends or retracts, the three joints rotate in coordination, enabling the upper fixed ring 1 to achieve spatial translation and rotation in any direction.

[0085] like Figure 3 As shown, both the first U-shaped joint 4 and the second U-shaped joint 7 are biaxial joint structures 6, with their two rotation axes 5 maintaining a preset distance in space, forming a non-common distribution. Compared with traditional cruciate joints, this design eliminates interaxial interference, increases the joint swing angle range from ±30° to over ±45°, and improves the joint's radial and axial load-bearing capacity, enabling it to withstand multi-directional forces during fracture reduction.

[0086] like Figure 4As shown, the specific connection method of the drive assembly is as follows: the boss of the motor housing 15 is precisely fitted into the groove of the gear housing 12, and then axially fixed by a set screw; the motor 16 is installed inside the motor housing 15, and the output shaft is coaxially connected to the drive gear 14 by a flat key; the drive gear 14 meshes externally with the driven gear 10, and the transmission ratio is 1:3; the driven gear 10 has a trapezoidal internal thread machined in the center, which cooperates with the trapezoidal external thread of the lead screw to form a helical transmission pair; the upper and lower ends of the driven gear 10 are supported in the gear housing 12 by bearing 9 and bearing 11 respectively, and the gear cover 8 is fixed to the upper end of the gear housing 12 by screws to press the bearing 9; the sleeve 13 is fixed to the lower end of the gear housing 12 by screws and set screws to provide guidance and protection for the extension and retraction of the lead screw; the lower end of the sleeve 13 is connected to the lower fixing ring 3 through a third U-shaped joint, and the third U-shaped joint also adopts a non-concurrent double-axis structure.

[0087] When the motor 16 is powered on and rotates, it drives the drive gear 14 to rotate, and the drive gear 14 drives the driven gear 10 to rotate around its own axis.

[0088] Driven gear 10 is rotatably supported in gear housing 12 by bearing 1 9 and bearing 2 11 to ensure rotational accuracy and smooth operation; drive gear 14 is made of self-lubricating material and does not require additional bearing 5 support; motor 16 is fixed in motor housing 15, which is fixed to gear housing 12 by set screws; sleeve 13 is fixed to the end of gear housing 12 by screws and / or set screws.

[0089] Driven gear 10 is supported by two deep groove ball bearings, with the inner ring of the bearings having an interference fit with the journal of the driven gear shaft and the outer ring having an interference fit with the inner hole of the gear housing 12, so that driven gear 10 can rotate freely around its own axis and bear radial and axial loads.

[0090] Self-lubricating materials (such as IGS) contain solid lubricants. When gears mesh, the lubricant is transferred to the tooth surface to form a lubricating film, achieving oil-free lubrication.

[0091] After the set screw is tightened, its end presses against the surface of the connected parts, generating a large frictional force to achieve axial and circumferential fixation; when used in conjunction with screws, it can significantly improve the resistance to loosening.

[0092] The first U-shaped joint 4 is connected to one end of the lead screw by a threaded engagement and is provided with a set screw for circumferential locking; the second U-shaped joint 7 is also connected to the other end of the lead screw by a threaded engagement and is provided with a set screw; the connection between the third U-shaped joint and the sleeve 13 is also provided with a set screw locking structure.

[0093] The U-shaped joint is machined with internal threads at one end and the lead screw is machined with external threads at the other end. The connection is achieved by thread engagement, and the threaded connection has high positioning accuracy and axial load capacity.

[0094] The set screw is screwed in through the radial threaded hole, and the end presses against the surface of the screw rod or sleeve, generating radial pressure, increasing the friction between the threaded contact surfaces, preventing relative rotation of the threads, and achieving circumferential locking.

[0095] This embodiment also includes a control system, which includes: a main control unit; six motor 16 drivers, each electrically connected to the main control unit and the six sets of sliding components 2, for independently driving the operation of each motor 16; multiple sensors, electrically connected to the main control unit, for detecting the displacement of each sliding component 2 or the rotation angle of the motor 16; a signal buffer isolation module, connected between the main control unit and the motor 16 drivers, for enhancing the driving capability of the driving signal and isolating electrical interference; a power management module, for converting externally input DC power into multiple DC power supplies of different voltages, for powering the main control unit, motor 16 drivers, and sensors; and a communication interface for exchanging data with an external host computer or surgical navigation system.

[0096] The main control unit receives the reset trajectory data sent by the host computer, calculates the target length of the six sliding components 2 at each moment according to the inverse kinematics model of the parallel mechanism, and generates PWM speed regulation, direction and enable signals.

[0097] The motor driver drives the motor 16 to operate according to the control signal, and the sensor detects the actual displacement or speed in real time and feeds it back to the main control unit.

[0098] The main control unit compares the actual value with the target value using a PID algorithm, adjusts the control signal, and achieves closed-loop control.

[0099] The signal buffer isolation module amplifies and electrically isolates weak electrical signals, blocking electromagnetic interference from the motor side from being transmitted to the main control unit.

[0100] The power management module provides appropriate power voltages to different components through graded step-down and voltage regulation.

[0101] The Motor 16 driver is an integrated H-bridge driver chip with PWM speed regulation, direction control, enable control, fault detection and current detection functions. The current detection pin of the driver chip is connected to ground through a sampling resistor, which is connected to the ADC input of the main control unit to realize current closed-loop control or overcurrent protection.

[0102] The H-bridge circuit controls the on / off states of four power switching transistors to change the polarity of the voltage across the motor, thus achieving forward and reverse rotation; it also adjusts the average voltage by regulating the on-time of the switching transistors using PWM signals, thereby achieving speed regulation.

[0103] The integrated driver chip integrates power switching transistors, drive circuits, protection circuits, and current detection circuits, eliminating the need to build complex discrete circuits.

[0104] The current detection circuit converts the motor current into a voltage signal through a sampling resistor, which is then amplified internally and output. The main control unit acquires this signal through an ADC, calculates the motor current, and immediately stops driving when the current exceeds a threshold.

[0105] The signal buffer isolation module includes at least one bidirectional buffer chip. The input of the bidirectional buffer chip is connected to the main control unit, and the output is connected to the motor driver. The operating voltage of the bidirectional buffer chip is compatible with the logic voltage of the main control unit.

[0106] The bidirectional buffer consists of multiple tri-state buffers, and the data transmission direction is controlled by the DIR pin. The tri-state buffer has high input impedance and low output impedance, and can drive multiple loads.

[0107] The power supply of the buffer chip shares a common ground with the power supply of the main control unit but is powered independently, effectively blocking the conduction path of electrical interference.

[0108] The power management module includes: a first-stage DC-DC step-down circuit that steps down the input high-voltage DC power to a first intermediate voltage; at least one second-stage LDO voltage regulator circuit that further steps down the first intermediate voltage to a stable logic voltage to power the main control unit and sensors; and a power supply branch for motor 16 that supplies the input high-voltage DC power directly or after filtering to the motor 16 driver.

[0109] A DC-DC circuit converts the input DC voltage into high-frequency pulses by switching the transistor on and off at high frequency. The pulses are then filtered by an inductor and capacitor to obtain a stable output voltage. The output voltage can be changed by adjusting the duty cycle.

[0110] The LDO circuit uses an internal error amplifier and regulating transistor to adjust the output voltage in real time, keeping it stable and unaffected by changes in input voltage and load.

[0111] The motor power supply branch is filtered by large-capacity electrolytic capacitors and ceramic capacitors. The electrolytic capacitors provide instantaneous large current, while the ceramic capacitors filter out high-frequency noise.

[0112] The sensor includes an encoder mounted on the motor 16, or a linear displacement sensor mounted on the sliding assembly 2; the communication interface is at least one of a CAN bus interface, an RS interface, an Ethernet interface, or a wireless communication module.

[0113] The photoelectric encoder converts the motor rotation angle into a pulse signal through photoelectric conversion. The main control unit counts the number and frequency of pulses, calculates the motor speed and rotation angle, and then calculates the displacement of the sliding component 2 based on the lead screw.

[0114] Linear displacement sensors (such as magnetostrictive sensors) measure displacement by detecting changes in magnetic fields and directly output an electrical signal proportional to the displacement, with measurement accuracy down to the micrometer level.

[0115] The communication interface converts digital signals into transmission signals according to the corresponding protocol, enabling data exchange between the robot and external devices.

[0116] The control system in this embodiment adopts an embedded system based on the STM32F407 microcontroller, and its block diagram is as follows. Figure 5 As shown. The main control unit is responsible for receiving the reset trajectory command sent by the host computer, performing kinematic calculations, and generating control signals for six sets of motors 16; the six motor drivers receive the control signals from the main control unit respectively and drive the corresponding motors 16 to operate; photoelectric encoders are installed on the motors 16 to detect the rotation angle of the motors 16 and feed it back to the main control unit to achieve closed-loop position control; the signal buffer isolation module uses a 74HC245 bidirectional buffer chip to buffer and isolate the PWM, direction, and enable signals output by the main control unit, enhancing the driving capability and protecting the main control unit; the power management module converts the input 24V DC power supply into 5V and 3.3V DC power supplies to power the motor drivers, the main control unit, and the sensors respectively; the communication interface uses a CAN bus interface to achieve high-speed data exchange with the surgical navigation system.

[0117] Figure 6 The schematic diagram of the motor drive circuit for one of the sliding components 2 is shown, employing the DRV8874 integrated H-bridge driver chip. This chip can provide a peak current of up to 6A, supports PWM speed regulation and direction control, and features overcurrent, overheat, and undervoltage protection. The current sensing pin IPROPI converts the motor current into a voltage signal through a 5.5kΩ sampling resistor, which is then fed into the ADC input of the main control unit to achieve current closed-loop control and overcurrent protection.

[0118] Figure 7 The schematic diagram of the signal buffer circuit is shown, employing the 74HC245 eight-channel bidirectional buffer chip. This chip operates at 3.3V, compatible with the logic levels of the main control unit. The direction control pin DIR is connected high, allowing data to flow from side A to side B; the output enable pin nOE is grounded, keeping the chip always enabled. The control signals output from the main control unit are buffered by the 74HC245 and then connected to the input of the DRV8874, effectively enhancing the signal driving capability and anti-interference ability.

[0119] Before surgery, three-dimensional medical images of the fracture site are acquired via CT or MRI, and the optimal reduction trajectory is planned in the surgical navigation system. The reduction trajectory data is sent to the robot's main control unit via the CAN bus. The main control unit calculates the required target lengths of the six sliding components 2 in real time based on the trajectory and generates corresponding PWM duty cycles and direction signals using a PID control algorithm. After the control signals are buffered and isolated by the signal buffer module, they drive each motor 16 to operate, causing the six sliding components 2 to generate corresponding extension and retraction, thereby driving the upper fixation ring 1 to move according to the planned trajectory and complete the fracture reduction. The current detection module monitors the motor current in real time. If an overcurrent occurs, the drive is immediately stopped and a fault is reported to ensure surgical safety.

[0120] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A long bone fracture robot, characterized in that, include: Upper fixing ring; Lower fixing ring; And six sets of sliding components are connected between the upper fixed ring and the lower fixed ring. The six sets of sliding components are distributed around the space and together form a parallel mechanism, so that the upper fixed ring can achieve six degrees of freedom of spatial motion relative to the lower fixed ring. Each set of sliding components includes a lead screw assembly and a drive assembly. The lead screw assembly includes a lead screw and at least one U-shaped joint. The U-shaped joint is connected between the end of the lead screw and the corresponding fixed ring. The two rotation axes of the U-shaped joint maintain a non-coordinated distribution structure with a preset distance in space.

2. The long bone fracture robot according to claim 1, characterized in that, The lead screw assembly includes a first U-shaped joint and a second U-shaped joint. The first U-shaped joint is connected to the upper fixed ring, and the second U-shaped joint is connected to one end of the lead screw. The drive assembly includes a gear housing, a motor, a driving gear, a driven gear, a sleeve, and a third U-shaped joint. The motor is fixedly mounted on the gear housing, and its output shaft is connected to the driving gear. The driven gear is rotatably disposed within the gear housing and meshes with the driving gear. The driven gear has an internal thread at its center, which engages with the external thread of the lead screw. The sleeve is fixedly connected to the gear housing, and the third U-shaped joint is connected between the sleeve and the lower fixed ring. The two rotation axes of the first U-shaped joint, the second U-shaped joint, and the third U-shaped joint all adopt a non-common point distribution structure.

3. The long bone fracture robot according to claim 2, characterized in that, The driven gear is rotatably supported within the gear housing by bearing one and bearing two to ensure rotational accuracy and smooth operation; the driving gear is made of self-lubricating material and requires no additional bearing support; the motor is fixed within the motor housing, and the motor housing is fixed to the gear housing by set screws; the sleeve is fixed to the end of the gear housing by screws and / or set screws.

4. The long bone fracture robot according to claim 2, characterized in that, The first U-shaped joint is connected to one end of the lead screw by a threaded engagement and is provided with a set screw for circumferential locking; the second U-shaped joint is also connected to the other end of the lead screw by a threaded engagement and is provided with a set screw; the connection between the third U-shaped joint and the sleeve is also provided with a set screw locking structure.

5. The long bone fracture robot according to claim 1, characterized in that, It also includes a control system, which comprises: a main control unit; six motor drivers, each electrically connected to the main control unit and the motors in the six sets of sliding components, for independently driving each motor; multiple sensors, electrically connected to the main control unit, for detecting the displacement of each sliding component or the rotation angle of the motor; a signal buffer isolation module, connected between the main control unit and the motor drivers, for enhancing the driving capability of the driving signal and isolating electrical interference; a power management module, for converting externally input DC power into multiple DC power supplies of different voltages, for powering the main control unit, motor drivers, and sensors respectively; and a communication interface for exchanging data with an external host computer or surgical navigation system.

6. The long bone fracture robot according to claim 5, characterized in that, The motor driver is an integrated H-bridge driver chip with PWM speed regulation, direction control, enable control, fault detection and current detection functions; the current detection pin of the driver chip is connected to ground through a sampling resistor, which is connected to the ADC input terminal of the main control unit to realize current closed-loop control or overcurrent protection.

7. The long bone fracture robot according to claim 5, characterized in that, The signal buffer isolation module includes at least one bidirectional buffer chip. The input terminal of the bidirectional buffer chip is connected to the main control unit, and the output terminal is connected to the motor driver. The operating voltage of the bidirectional buffer chip is compatible with the logic voltage of the main control unit.

8. The long bone fracture robot according to claim 5, characterized in that, The power management module includes: a first-stage DC-DC step-down circuit to step down the input high-voltage DC power to a first intermediate voltage; at least one second-stage LDO voltage regulator circuit to further step down the first intermediate voltage to a stable logic voltage to power the main control unit and sensors; and a motor power supply branch to supply the input high-voltage DC power directly or after filtering to the motor driver.

9. The long bone fracture robot according to claim 5, characterized in that, The sensor includes an encoder mounted on the motor, or a linear displacement sensor mounted on the sliding assembly; the communication interface is at least one of a CAN bus interface, an RS interface, an Ethernet interface, or a wireless communication module.

10. The long bone fracture robot according to claim 1, characterized in that, Both the upper and lower fixing rings are provided with six connecting holes for fixed connection to the two ends of the six sets of sliding components by fasteners; at least a portion of the upper fixing ring, lower fixing ring and sliding components are made of lightweight alloy or carbon fiber composite material.

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