A passive gravity compensation mechanism for the main operator

Abstract

This invention discloses a passive gravity compensation mechanism for a main operator, comprising a frame, a drive assembly, and a balancing assembly. The drive assembly includes a driver, a first lead wheel, and a drive element. The balancing assembly includes a first guide wheel, a balancing transmission wire, and a balancing element. The driver drives the first lead wheel to rotate, which in turn drives the drive element to rotate. Simultaneously, the rotation of the first lead wheel pulls the balancing element via the connected balancing transmission wire, causing the balancing element to deform and generate elastic potential energy. This elastic potential energy counteracts the work done by the gravity of the drive element, achieving passive gravity compensation. The elastic potential energy provided by the balancing element is determined by the stiffness and length change of the balancing element, the mass of the drive element, the distance between the center of mass of the drive element and the axis of the first lead wheel, the angle between the current direction of the drive element and the direction of gravity, and the parameters of the guide wheel assembly. By adjusting these factors, the operating parameters of the mechanism can be changed, improving the flexibility and adaptability of the compensation mechanism.

Description

Technical Field

[0001] This invention relates to the field of medical devices and related supporting facilities, and in particular to a passive gravity compensation mechanism for a main operator. Background Technology

[0002] Compared to traditional minimally invasive surgery, robot-assisted minimally invasive surgery has seen significant development due to its high positioning accuracy, short operation time, high dexterity, and fewer postoperative complications. Currently, master-slave systems are used in most robots. The master manipulator maps the surgeon's commands to the slave manipulator and provides force feedback to the surgeon. In addition to possessing a sufficiently large workspace, flexible movement dexterity, and high force feedback accuracy required for surgical operations, the master manipulator should also be ergonomically designed as much as possible and minimize the additional energy consumption of the drive motors. Furthermore, in the event of a sudden power outage or control system malfunction during surgery, the master manipulator should ideally be able to maintain stability mechanically, improving operational safety. Gravity-compensated master manipulator joint drive torque can balance the torque required for the current operating state, allowing the surgeon to operate the master manipulator with minimal force, thus completing surgical tasks comfortably and efficiently.

[0003] Currently, gravity compensation methods for the main operator can be divided into two types: active gravity compensation and passive gravity compensation. Active gravity compensation achieves gravity compensation through motor output torque; however, when the main operator is stationary, the drive motor consumes additional energy. Passive gravity compensation mainly achieves this through weight balancing and the introduction of a zero-initial-length spring. Weight balancing is based on the lever principle, but this results in a bulky main operator that is not ergonomically designed. A zero-initial-length spring refers to a spring whose length is zero when the net external force acting on it is zero. Introducing a zero-initial-length spring requires the addition of a guide wheel and a transmission wire. Chinese patent CN105234959B discloses a mechanism for achieving main operator gravity compensation by introducing a tension spring balancing component. By changing the position of the tension spring balancing component on the swing component, the main operator can maintain self-balancing ability in any posture; however, the design of the mechanical structure is limited by the parameters of the tension spring balancing component itself. Chinese patent CN107175652B discloses a gravity compensation mechanism applicable to upper limb exoskeletons. This gravity compensation mechanism introduces a movable pulley to reduce the tensile deformation of the spring. However, the movable pulley is fixedly connected to the slider accessory, which increases the friction of the system and affects the accuracy of the force feedback of the main operator. Summary of the Invention

[0004] The purpose of this invention is to provide a passive gravity compensation mechanism for the main operator, so as to solve the problems existing in the prior art, reduce the energy consumption of the compensation mechanism, and improve the flexibility and adaptability of the compensation mechanism.

[0005] To achieve the above objectives, the present invention provides the following solution: The present invention provides a passive gravity compensation mechanism for a main operator, comprising:

[0006] frame;

[0007] A drive assembly includes a driver, a first wire wheel, and a drive element. The first wire wheel is rotatably mounted on the frame. The output end of the driver is connected to the first wire wheel. The drive element is connected to the first wire wheel and can be connected to a main operating hand component.

[0008] A balancing assembly includes a first guide wheel, a balancing transmission wire, and a balancing element. The first guide wheel is rotatably mounted on the frame, and its rotation axis is parallel to the rotation axis of the first wire wheel. One end of the balancing transmission wire is connected to the first wire wheel, and the connection point between the balancing transmission wire and the first wire wheel does not coincide with the rotation axis of the first wire wheel. In the initial state, the line connecting the connection point of the balancing transmission wire and the first wire wheel to the center of mass of the driving element is parallel to the vertical direction. The other end of the balancing transmission wire passes around the first guide wheel and is connected to one end of the balancing element. The other end of the balancing element is connected to the frame, and the balancing element is an elastic body.

[0009] Preferably, the output end of the driver is connected to a second wire wheel, which is connected to the first wire wheel via a drive transmission wire.

[0010] Preferably, one end of the drive transmission wire is connected to the second wire wheel, and the other end of the drive transmission wire is connected to the first wire wheel. There are two drive transmission wires, and the two drive transmission wires are symmetrically arranged with the line connecting the centers of the first wire wheel and the second wire wheel as the axis.

[0011] Preferably, the two drive transmission wires are arranged in a cross configuration.

[0012] Preferably, the balancing assembly further includes a guide wheel group, which includes a second guide wheel, a third guide wheel, and a timing belt. The second guide wheel is connected to the first threaded wheel and the two are coaxially arranged. The third guide wheel is rotatably arranged on the first threaded wheel. The second guide wheel drives the third guide wheel to rotate by the timing belt. The line connecting the centers of the second guide wheel and the third guide wheel is parallel to the line connecting the center of mass of the driving element and the center of the first threaded wheel. The balancing transmission wire is connected to the third guide wheel.

[0013] Preferably, the third guide wheel is connected to a fourth guide wheel, the fourth guide wheel is coaxially arranged with the third guide wheel, and the balance transmission wire is connected to the fourth guide wheel.

[0014] Preferably, the balancing element is a zero-initial-length spring.

[0015] Preferably, the driving element is a parallelogram mechanism.

[0016] Preferably, the driving element includes a first link, a second link, a third link, and a fourth link. One end of the first link is hinged to the first lead wheel, and the hinge axis between the first link and the first lead wheel coincides with the rotation axis of the first lead wheel. The other end of the first link is hinged to one end of the second link, the other end of the second link is hinged to one end of the third link, the other end of the third link is hinged to one end of the fourth link, and the other end of the fourth link is hinged to the first lead wheel, with the hinge axis between the fourth link and the first lead wheel coinciding with the rotation axis of the first lead wheel. The first link, the second link, the third link, and the fourth link form a parallelogram mechanism, and the fourth link can be connected to the main operating hand component.

[0017] The present invention achieves the following technical effects compared to the prior art:

[0018] The passive gravity compensation mechanism of the main operator of this invention involves a driver that rotates a first lead wheel, which in turn rotates a drive element. Simultaneously, the rotation of the first lead wheel pulls a balancing element via a connected balancing transmission wire, causing the balancing element to deform and generate elastic potential energy. This elastic potential energy counteracts the work done by the gravity of the drive element, achieving passive gravity compensation. This passive gravity compensation mechanism remains stable even when the main operator component malfunctions or experiences a power outage. It requires no additional energy consumption when the mechanism is stationary, reducing energy consumption and saving energy. The first lead wheel is connected to the balancing transmission wire, which, after passing around the first guide wheel, connects to the balancing element, reducing friction and improving transmission accuracy. Furthermore, the elastic potential energy provided by the balancing element is determined by the stiffness and length change of the balancing element, the mass of the drive element, the distance between the center of mass of the drive element and the axis of the first lead wheel, and the angle between the current direction of the drive element and the direction of gravity. Adjusting these factors changes the working parameters of the mechanism, improving its flexibility and adaptability. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the passive gravity compensation mechanism for the main operator of the present invention.

[0021] Figure 2 This is a schematic diagram of the passive gravity compensation mechanism of the main operator of the present invention.

[0022] Figure 3 This is a schematic diagram of the passive gravity compensation mechanism for the main operator of the present invention.

[0023] Figure 4 This is a schematic diagram of another embodiment of the passive gravity compensation mechanism for the main operator of the present invention;

[0024] Figure 5 This is a schematic diagram of the drive element in another embodiment of the passive gravity compensation mechanism for the main operator of the present invention.

[0025] Among them, 100 is the rack, 200 is the drive assembly, and 300 is the balancing assembly;

[0026] 1 is the driver, 2 is the first lead wheel, 3 is the driving element, 4 is the first guide wheel, 5 is the balancing transmission wire, 6 is the balancing element, 7 is the second lead wheel, 8 is the driving transmission wire, 9 is the guide wheel group, 10 is the second guide wheel, 11 is the third guide wheel, 12 is the synchronous belt, 13 is the fourth guide wheel, 14 is the first connecting rod, 15 is the second connecting rod, 16 is the third connecting rod, and 17 is the fourth connecting rod. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] The purpose of this invention is to provide a passive gravity compensation mechanism for the main operator, so as to solve the problems existing in the prior art, reduce the energy consumption of the compensation mechanism, and improve the flexibility and adaptability of the compensation mechanism.

[0029] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] This invention provides a passive gravity compensation mechanism for a main operator, comprising a frame 100, a drive assembly 200, and a balancing assembly 300. The drive assembly 200 includes a driver 1, a first threaded wheel 2, and a drive element 3. The first threaded wheel 2 is rotatably mounted on the frame 100. The output end of the driver 1 is connected to the first threaded wheel 2. The drive element 3 is connected to the first threaded wheel 2 and can be connected to a main operator component. The balancing assembly 300 includes a first guide wheel 4, a balancing transmission wire 5, and a balancing element 6. The first guide wheel 4 is rotatably mounted on the frame 100. Placed on the frame 100, the rotation axis of the first guide wheel 4 is parallel to the rotation axis of the first thread wheel 2. One end of the balance transmission wire 5 is connected to the first thread wheel 2. The connection point between the balance transmission wire 5 and the first thread wheel 2 does not coincide with the rotation axis of the first thread wheel 2. In the initial state, the line connecting the connection point between the balance transmission wire 5 and the first thread wheel 2 and the center of mass of the drive element 3 is parallel to the vertical direction. The other end of the balance transmission wire 5 passes around the first guide wheel 4 and is connected to one end of the balance element 6. The other end of the balance element 6 is connected to the frame 100. The balance element 6 is an elastic body.

[0031] The passive gravity compensation mechanism of the main operator of this invention involves a driver 1 driving a first lead wheel 2 to rotate, which in turn drives a driving element 3 to rotate. Simultaneously, the rotation of the first lead wheel 2 is achieved by using a connected balance transmission wire 5 to pull a balance element 6, causing the balance element 6 to deform and generate elastic potential energy. This elastic potential energy counteracts the work done by the gravity of the driving element 3, thus achieving passive gravity compensation. This passive gravity compensation mechanism maintains stability even when the main operator component malfunctions or experiences a power outage. It requires no additional energy consumption when the mechanism is stationary, reducing energy consumption and saving energy. The first lead wheel 2 is connected to the balance transmission wire 5, which, after passing around the first guide wheel 4, connects to the balance element 6, reducing friction and improving transmission accuracy. Furthermore, the elastic potential energy provided by the balance element 6 is determined by the stiffness and length change of the balance element 6, the mass of the driving element 3, the distance between the center of mass of the driving element 3 and the axis of the first lead wheel 2, and the angle between the current direction of the driving element 3 and the direction of gravity. Adjusting these factors can change the working parameters of the mechanism, improving its flexibility and adaptability.

[0032] It should be explained here that the frame 100 can be a separate support structure. In practical applications, the frame 100 can also be other structures of the main operator, or components that provide support for the compensation mechanism.

[0033] The output end of the driver 1 is connected to the second wire wheel 7. The second wire wheel 7 is connected to the first wire wheel 2 via the drive transmission wire 8. The driver 1 can be a motor. The driver 1 drives the second wire wheel 7 to rotate, and then drives the first wire wheel 2 to rotate via the drive transmission wire 8.

[0034] Specifically, one end of the drive transmission wire 8 is connected to the second threaded wheel 7, and the other end of the drive transmission wire 8 is connected to the first threaded wheel 2. There are two drive transmission wires 8, and the two drive transmission wires 8 are symmetrically arranged about the line connecting the centers of the first threaded wheel 2 and the second threaded wheel 7 as the axis of symmetry. Figure 4 As shown, in this specific embodiment, when the drive transmission wire 8 does not cross the axis of symmetry, the driver 1 drives the second wire wheel 7 to rotate clockwise. Under the action of the two drive transmission wires 8, the first wire wheel 2 rotates clockwise, and correspondingly, the drive element 3 rotates clockwise. When the driver 1 drives the second wire wheel 7 to rotate counterclockwise, the second wire wheel 7 uses the drive transmission wires 8 to drive the first wire wheel 2 to rotate counterclockwise.

[0035] To reduce wear on the drive transmission wire 8 during use, a thread groove is provided on the outer circumferential surface of the second thread wheel 7, so that the drive transmission wire 8 can be fed along the thread groove. Meanwhile, the outer circumferential surface of the first thread wheel 2 is made as smooth as possible to reduce friction between the drive transmission wire 8 and the first thread wheel 2, extend the service life of the drive transmission wire 8, and ensure the normal operation of the mechanism.

[0036] In other specific embodiments of the present invention, the two drive transmission wires 8 can be arranged in a cross configuration, such as... Figure 1 and Figure 2 As shown, one end of the drive transmission wire 8 is connected to the second wheel 7, and the other end of the drive transmission wire 8 is connected to the first wheel 2 across the axis of symmetry. The driver 1 drives the second wheel 7 to rotate clockwise. Under the action of the two drive transmission wires 8, the first wheel 2 rotates counterclockwise, and correspondingly, the drive element 3 rotates counterclockwise. When the driver 1 drives the second wheel 7 to rotate counterclockwise, the second wheel 7, through the drive transmission wires 8, drives the first wheel 2 to rotate clockwise, which in turn pulls the balance transmission wire 5, causing the balance element 6 to deform and provide elastic potential energy. In practical applications, the connection direction of the drive transmission wires 8 can be selected according to the actual situation to improve the flexibility and adaptability of the mechanism. In addition, the winding amount of the drive transmission wires 8 can be adjusted according to the actual situation to ensure a certain working range of the drive element 3.

[0037] More specifically, the balancing assembly 300 further includes a guide wheel group 9, which includes a second guide wheel 10, a third guide wheel 11, and a synchronous belt 12. The second guide wheel 10 is connected to the first lead wheel 2 and the two are coaxially arranged. The third guide wheel 11 is rotatably arranged on the first lead wheel 2. The second guide wheel 10 drives the third guide wheel 11 to rotate using the synchronous belt 12. The line connecting the centers of the second guide wheel 10 and the third guide wheel 11 is parallel to the line connecting the center of mass of the driving element 3 and the center of the first lead wheel 2. The balancing transmission wire 5 is connected to the third guide wheel 11. The second guide wheel 10 and the first lead wheel 2 are coaxially arranged, and the first lead wheel 2 can drive the second guide wheel 10 to rotate coaxially. The second guide wheel 10 uses the synchronous belt 12 to realize the rotation of the third guide wheel 11. The third guide wheel 11 drives the balancing transmission wire 5 to move, causing the balancing element 6 to deform. The present invention provides a guide wheel group 9, which allows adjustment of the elastic potential energy provided by the balancing element 6 by adjusting the radius ratio of the second guide wheel 10 and the third guide wheel 11 in the guide wheel group 9.

[0038] It should also be noted that the third guide wheel 11 is connected to the fourth guide wheel 13, which is coaxial with the third guide wheel 11. The balancing transmission wire 5 is connected to the fourth guide wheel 13. The axis of the fourth guide wheel 13, the axis of the first wire wheel 2, and the center of mass of the driving element 3 are coplanar, so that the elastic potential energy generated by the deformation of the balancing element 6 can balance the work done by the gravity of the driving assembly 200. In addition, the balancing assembly 300 and the driving assembly 200 are connected in parallel through the second wire wheel 7 and the guide wheel group 9, which avoids the oscillation phenomenon of the driving transmission wire 8 caused by the series connection of the balancing assembly 300 and the driving assembly 200, and improves the transmission accuracy of the driving transmission wire 8.

[0039] In this specific embodiment, the balancing element 6 is a zero-initial-length spring. In practical applications, the balancing element 6 can also be a component that can provide elastic potential energy.

[0040] In summary, during the movement of the drive element 3, the balancing transmission wire 5 pulls the balancing element 6, causing a change in the length of the balancing element 6. The elastic potential energy provided by the balancing element 6 counteracts the work done by the change in gravitational torque during the periodic rotation of the drive element 3, thereby achieving dynamic passive gravity compensation for the main operator. Figure 3 As shown, point A is the rotation center of the first guide wheel 4, point B is the rotation center of the first lead wheel 2, the distance between points A and B is a, point C is the rotation center of the third guide wheel 11, the distance between points B and C is b, the distance between point B and the center of mass of the driving element 3 is l, the angle between the current direction of the driving element 3 and its gravitational direction G during the movement is θ, the mass of the driving element 3 is m, the stiffness coefficient of the balancing element 6 is k, the length change of the balancing element 6 is Δx, and the diameter ratio of the second guide wheel 10 to the third guide wheel 11 is λ. Then, the potential energy of the passive balancing mechanism can be expressed as:

[0041]

[0042] The change in length Δx of balancing element 6 can be expressed as:

[0043] Δx=a 2 +b 2 +2abcosθ

[0044] The energy of the passive gravity compensation mechanism of this invention is conserved, therefore:

[0045]

[0046] The elastic potential energy provided by balancing element 6 is determined by k, Δx, a, b, θ, λ, m, and l. Furthermore, the elastic potential energy provided by balancing element 6 can be scaled by changing the value of λ. Specifically, when λ is greater than 1, the elastic potential energy provided by balancing element 6 is reduced; when λ is less than 1, the elastic potential energy of balancing element 6 is amplified.

[0047] In addition, in other specific embodiments of the present invention, the driving element 3 can be a parallelogram mechanism. The use of a parallelogram mechanism for the driving element 3 can effectively improve the stability of the driving element 3 and further improve the operational safety factor of the main operator.

[0048] When the driving element 3 adopts a parallelogram mechanism, the driving element 3 includes a first connecting rod 14, a second connecting rod 15, a third connecting rod 16, and a fourth connecting rod 17. One end of the first connecting rod 14 is hinged to the first lead wheel 2, and the hinge axis between the first connecting rod 14 and the first lead wheel 2 coincides with the rotation axis of the first lead wheel 2. The other end of the first connecting rod 14 is hinged to one end of the second connecting rod 15, the other end of the second connecting rod 15 is hinged to one end of the third connecting rod 16, and the other end of the third connecting rod 16 is hinged to the fourth connecting rod 17. One end of the fourth link 17 is hinged, and the other end of the fourth link 17 is hinged to the first lead wheel 2. The hinge axis of the fourth link 17 and the first lead wheel 2 coincides with the rotation axis of the first lead wheel 2. The first link 14, the second link 15, the third link 16 and the fourth link 17 form a parallelogram mechanism. The fourth link 17 can be connected to the main operating hand component. The first link 14 and the third link 16 always remain parallel, thereby avoiding the influence of the second link 15 on the main operating hand component connected to the fourth link 17 during the movement.

[0049] The passive gravity compensation mechanism for the main operator of this invention includes a drive assembly 200 and a balancing assembly 300. The drive assembly 200 is used to realize the power output of the drive element 3, and the balancing assembly 300 is used to provide elastic potential energy to realize the dynamic balance of the gravitational torque change during the periodic rotation of the drive element 3. The elastic potential energy required to be provided by the balancing element 6 is determined by the stiffness of the balancing element 6, the amount of change in the length of the balancing element 6, the mass of the drive element 3, the distance between the center of mass of the drive element 3 and its rotation center, the angle between the current direction of the drive element 3 and its gravity direction, and the relative distance and geometric dimensions between the second guide wheel 10 and the third guide wheel 11 in the guide wheel assembly 9. The passive gravity compensation mechanism of this invention makes the selection of the balancing element 6 and the design of the mechanical mechanism more flexible, greatly improving the adaptability of the compensation mechanism.

[0050] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A passive gravity compensation mechanism for a main operator, characterized in that, include: frame; A drive assembly includes a driver, a first wire wheel, and a drive element. The first wire wheel is rotatably mounted on the frame. The output end of the driver is connected to the first wire wheel. The drive element is connected to the first wire wheel and can be connected to a main operating hand component. A balancing assembly includes a first guide wheel, a balancing transmission wire, and a balancing element. The first guide wheel is rotatably mounted on the frame, and its rotation axis is parallel to the rotation axis of the first wire wheel. One end of the balancing transmission wire is connected to the first wire wheel, and the connection point between the balancing transmission wire and the first wire wheel does not coincide with the rotation axis of the first wire wheel. In the initial state, the line connecting the connection point between the balancing transmission wire and the first wire wheel and the center of mass of the driving element is parallel to the vertical direction. The other end of the balancing transmission wire passes around the first guide wheel and is connected to one end of the balancing element. The other end of the balancing element is connected to the frame, and the balancing element is an elastic body. The balancing assembly further includes a guide wheel group, which includes a second guide wheel, a third guide wheel, and a timing belt. The second guide wheel is connected to the first threaded wheel and the two are coaxially arranged. The third guide wheel is rotatably arranged on the first threaded wheel. The second guide wheel drives the third guide wheel to rotate by the timing belt. The line connecting the centers of the second guide wheel and the third guide wheel is parallel to the line connecting the center of mass of the driving element and the center of the first threaded wheel. The balancing transmission wire is connected to the third guide wheel.

2. The passive gravity compensation mechanism for the main operator according to claim 1, characterized in that: The output end of the driver is connected to a second wire wheel, which is connected to the first wire wheel via a drive transmission wire.

3. The passive gravity compensation mechanism for the main operator according to claim 2, characterized in that: One end of the drive transmission wire is connected to the second wire wheel, and the other end of the drive transmission wire is connected to the first wire wheel. There are two drive transmission wires, and the two drive transmission wires are symmetrically arranged with the line connecting the centers of the first wire wheel and the second wire wheel as the axis.

4. The passive gravity compensation mechanism for the main operator according to claim 3, characterized in that: The two drive transmission wires are arranged in a cross configuration.

5. The passive gravity compensation mechanism for the main operator according to claim 1, characterized in that: The third guide wheel is connected to the fourth guide wheel, and the fourth guide wheel is coaxially arranged with the third guide wheel. The balance transmission wire is connected to the fourth guide wheel.

6. The passive gravity compensation mechanism for the main operator according to any one of claims 1-5, characterized in that: The balancing element is a zero-initial-length spring.

7. The passive gravity compensation mechanism for the main operator according to any one of claims 1-5, characterized in that: The driving element is a parallelogram mechanism.

8. The passive gravity compensation mechanism for the main operator according to claim 7, characterized in that: The driving element includes a first link, a second link, a third link, and a fourth link. One end of the first link is hinged to the first lead wheel, and the hinge axis between the first link and the first lead wheel coincides with the rotation axis of the first lead wheel. The other end of the first link is hinged to one end of the second link, the other end of the second link is hinged to one end of the third link, the other end of the third link is hinged to one end of the fourth link, and the other end of the fourth link is hinged to the first lead wheel, with the hinge axis between the fourth link and the first lead wheel coinciding with the rotation axis of the first lead wheel. The first link, the second link, the third link, and the fourth link form a parallelogram mechanism, and the fourth link can be connected to the main operating hand component.

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