Elastic force assisted reversible balance mechanical arm joint

Abstract

The application provides a flexible force auxiliary reversible balance mechanical arm joint, which comprises a rotating shaft fixing arm, a load arm and an elastic member. The fixing arm is rotationally connected with the rotating shaft, and the rotation axis of the fixing arm is coincident with the axis of the rotating shaft. The fixing arm is provided with a driving part, and the output end of the driving part is connected with the rotating shaft. The load arm is fixedly connected with the rotating shaft and rotationally connected with the fixing arm around the axis of the rotating shaft. The load arm is used for mounting a rear end load. The first end of the elastic member is connected with the fixing arm, and the second end is eccentrically connected with the rotating shaft or the equivalent shaft of the rotating shaft. The equivalent shaft of the rotating shaft is a shaft parallel to the rotating shaft and synchronously rotating. The elastic member has a flexible force in the direction of the straight line where the first end and the second end are located. The flexible force of the elastic member generates an elastic torque acting on the rotating shaft. The elastic torque and the driving torque of the driving part are used for balancing the gravity torque of the overall gravity of the load arm and the rear end load acting on the rotating shaft.

Description

Technical Field

[0001] This invention belongs to the field of medical device technology, and in particular relates to an elastic force-assisted reversible balance robotic arm joint. Background Technology

[0002] In medical surgical robots, robotic arms driven by doctors are frequently used. These arms often include rotary joints with horizontal or near-horizontal axes. The rear end of these rotary joints (the end closest to the doctor's manipulation) naturally sags under gravity. When the doctor needs to lift the rear end, without motor assistance, they must overcome the weight of the entire rear end, making the operation feel heavy and causing fatigue during prolonged use.

[0003] Therefore, in existing technologies, a motor with an output capacity equivalent to the gravitational torque generated by the overall load at the back end is generally designed. This motor requires high power, which makes it large in size and mass. This requires the front end (the end away from the doctor's operation) joint to have a greater load capacity, ultimately resulting in the entire robotic arm being large and cumbersome.

[0004] Some solutions involve using a gravity load that is symmetrical to the overall load at the rear end relative to the joint axis to balance the overall load at the rear end. While this can effectively balance the overall load at the rear end, it not only greatly increases the volume of the rotary joint but also multiplies the load on the front joint, resulting in a bulky robotic arm with a less aesthetically pleasing appearance. Summary of the Invention

[0005] The purpose of this invention is to provide a reversible balance robotic arm joint with elastic force assistance, so as to solve the problem that the existing rotary joints are bulky due to the gravitational torque generated by balancing the overall load at the rear end.

[0006] The technical solution of this invention is as follows:

[0007] A reversible, balancing robotic arm joint assisted by elastic force, comprising:

[0008] Rotation axis;

[0009] A fixed arm is rotatably connected to the rotating shaft, and its rotation axis coincides with the axis of the rotating shaft; the fixed arm is provided with a driving part, and the output end of the driving part is connected to the rotating shaft;

[0010] A load arm is fixedly connected to the rotating shaft and rotatably connected to the fixed arm about the axis of the rotating shaft; the load arm is used to mount the rear load.

[0011] The elastic element has a first end connected to the fixed arm and a second end eccentrically connected to the rotating shaft or to the equivalent axis of the rotating shaft, wherein the equivalent axis of the rotating shaft is an axis that is parallel to and rotates synchronously with the rotating shaft.

[0012] The elastic element has an elastic force that contracts in the straight direction of its first and second ends. The elastic force of the elastic element generates an elastic torque acting on the rotating shaft. The elastic torque, in conjunction with the driving torque of the drive unit, is used to balance the gravitational torque acting on the rotating shaft by the overall gravity of the load arm and the rear load.

[0013] In one embodiment, an elastic force-assisted reversible balanced robotic arm joint is provided, wherein the second end of the elastic element is connected to the equivalent axis of the rotation axis;

[0014] The axis of the equivalent axis and the axis of the rotation axis are located in the same vertical plane, and the equivalent axis is located on the side of the rotation axis closer to the drive unit.

[0015] In one embodiment, the elastic force-assisted reversible balance robotic arm joint is such that when the elastic force of the elastic element is in the vertical direction, the lever arm of the gravitational torque is in the non-vertical direction.

[0016] In one embodiment, the elastic force-assisted reversible balance robotic arm joint has the line of elastic force of the elastic element perpendicular to or perpendicular to the axis of the rotation axis.

[0017] In one embodiment, an elastic force-assisted reversible balanced robotic arm joint is provided, wherein the second end of the elastic element is eccentrically positioned with respect to the rotation axis or the equivalent axis of the rotation axis via an auxiliary element.

[0018] One end of the auxiliary component is connected to the rotating shaft or the equivalent axis of the rotating shaft, and the other end is provided with a connecting post arranged parallel to the rotating shaft; the second end of the elastic component is connected to the first end of a pull rope, the second end of the pull rope forms a rope sleeve fitted on the connecting post, and the pull rope is in a straight state.

[0019] In one embodiment, an elastic force-assisted reversible balancing robotic arm joint is provided, wherein the auxiliary component is connected to the end face of the rotating shaft or its equivalent axis to prevent the movement of the pull rope from interfering with the rotating shaft or its equivalent axis.

[0020] In one embodiment, an elastic force-assisted reversible balanced robotic arm joint is provided, wherein the second end of the elastic element is eccentrically connected to the equivalent axis of the rotating shaft, and the equivalent axis is rotatably connected to the fixed arm.

[0021] The rotating shaft and the equivalent shaft are connected by a spur gear set, which includes a first spur gear and a second spur gear. The first spur gear is sleeved on the rotating shaft and coaxially and fixedly connected to the rotating shaft. The second spur gear is sleeved on the equivalent shaft and coaxially and fixedly connected to the equivalent shaft. The first spur gear and the second spur gear mesh.

[0022] In one embodiment, an elastic force-assisted reversible balance robotic arm joint is provided, wherein the drive unit is a motor, the motor is fixedly connected to the fixed arm, and the output shaft of the motor is connected to the rotating shaft through a bevel gear set;

[0023] The bevel gear set includes a first bevel gear and a second bevel gear. The first bevel gear is sleeved on the rotating shaft and is coaxially and fixedly connected to the rotating shaft. The second bevel gear is coaxially and fixedly connected to the output shaft of the motor.

[0024] In one embodiment, an elastic force-assisted reversible balance robotic arm joint is provided with a first axial end of the rotating shaft connected to the load arm, and an angular displacement sensor is provided between the second axial end of the rotating shaft and the fixed arm. The angular displacement sensor is used to detect the rotation angle of the rotating shaft relative to the fixed arm.

[0025] The second end of the elastic element is eccentrically connected to the equivalent axis of the rotating shaft.

[0026] In one embodiment, an elastic force-assisted reversible balancing robotic arm joint is provided, wherein the elastic element is a spring.

[0027] In one embodiment, an elastic force-assisted reversible balance robotic arm joint is provided, wherein the connection position between the first end of the elastic element and the fixed arm is adjustable to adjust the magnitude of the elastic force of the elastic element in the initial state of the robotic arm joint.

[0028] Because the present invention adopts the above technical solution, it has the following advantages and positive effects compared with the prior art:

[0029] The elastic force-assisted reversible balancing robotic arm joint provided by this invention utilizes the elastic force of an elastic element to generate an elastic torque acting on the rotation axis. This torque balances a portion of the gravitational torque acting on the rotation axis from the overall load at the rear end. The remaining gravitational torque is then balanced by the driving torque generated by the drive unit. The elastic element and the drive unit work together to balance all the gravitational torque generated by the overall load at the rear end, making the operation feel light and responsive for the surgeon. Therefore, compared to existing technologies, a lower-power drive unit can be used, resulting in a reduction in the size and weight of the drive unit, and consequently, a smaller joint volume. The gravitational torque acting on the rotation axis from the overall load at the rear end is the gravitational torque generated by the combined weight of the load arm and the rear load acting on the rotation axis.

[0030] Simultaneously, the lever arm of the gravitational torque reverses direction when passing through the vertical direction, thus requiring the lever arm of the torque generated by the balancing mechanism to also have the ability to reverse direction. In this invention, the second end of the elastic element is eccentrically connected to the rotation axis or to its equivalent axis. Therefore, when the rotation axis rotates one revolution, the second end of the elastic element will rotate one revolution around the axis of the rotation axis or around the axis of its equivalent axis. This allows the lever arm of the elastic torque generated by the elastic force of the elastic element acting on the rotation axis to change direction when passing through the vertical direction, meeting the requirement of reversible capability. Attached Figure Description

[0031] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention.

[0032] Figure 1 This is a schematic diagram of the working principle of a reversible balance robotic arm joint assisted by elastic force according to the present invention (the load arm in the figure is schematic and does not represent the actual structural shape).

[0033] Figure 2 This is a schematic diagram of an elastic force-assisted reversible balance robotic arm joint of the present invention when the connecting column is in the uppermost position;

[0034] Figure 3 This is a schematic diagram of an elastic force-assisted reversible balancing robotic arm joint of the present invention when the angle between the load arm and the fixed arm is zero.

[0035] Figure 4 This is a schematic diagram of an elastic force-assisted reversible balance robotic arm joint of the present invention when the connecting column is in the lowest position.

[0036] Explanation of reference numerals in the attached figures:

[0037] 1: Rotating shaft; 2: Load arm; 3: First housing; 4: Motor; 5: First bevel gear; 6: Second bevel gear; 7: First spur gear; 8: Second spur gear; 9: Auxiliary component; 10: Equivalent shaft; 11: Pull rope; 12: Elastic component; 13: Angular displacement sensor; 14: Adjusting block. Detailed Implementation

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without any creative effort.

[0039] To keep the drawings concise, only the parts relevant to the invention are shown schematically in each figure, and they do not represent the actual structure of the product. Furthermore, for ease of understanding, in some figures, only one of components with the same structure or function is shown schematically, or only one is labeled. In this document, "one" can mean not only "only one" but also "more than one".

[0040] See Figures 1 to 4 This embodiment provides a reversible, balancing, elastic force-assisted robotic arm joint for use in the teleoperation master hand of a laparoscopic master-slave assisted surgical robot. Specifically, the teleoperation master hand includes a position adjustment mechanism, a posture adjustment mechanism, and a control gripper connected in series, corresponding to the slave-end robotic arm, the execution tool, and the tool head of the execution tool, respectively; and the reversible, balancing, elastic force-assisted robotic arm joint provided in this embodiment serves as a joint within the posture adjustment mechanism. Of course, in other embodiments, the reversible, balancing, elastic force-assisted robotic arm joint can be used as a rotary joint in the position adjustment mechanism or a rotary joint in the teleoperation master hand of another master-slave assisted surgical robot, and is not limited here.

[0041] For ease of explanation, the elastic force-assisted reversible balance robotic arm joint will be referred to simply as a robotic arm joint in the following text. In this article, the rear end refers to the end closer to the doctor's operation, and the front end refers to the end farther away from the doctor's operation.

[0042] Main reference Figure 1 The robotic arm joint provided in this embodiment includes a rotating shaft 1, a fixed arm, a load-bearing arm 2, and an elastic element 12. The rotating shaft 1 passes through the fixed arm and is rotatably connected to it, with its rotation axis coinciding with the axis of the rotating shaft 1. The load-bearing arm 2 is fixed to the first axial end of the rotating shaft 1, thereby achieving a rotatable connection between the load-bearing arm 2 and the fixed arm; and the rotation axes of the load-bearing arm 2 and the fixed arm coincide with the axis of the rotating shaft 1. It should be noted that the ideal working state of the robotic arm joint provided in this embodiment is as follows: the length direction of the fixed arm is vertical, and the axis of the rotating shaft 1 is located in a horizontal plane.

[0043] An angular displacement sensor 13 is connected to the second axial end of the rotating shaft 1. The angular displacement sensor 13 is disposed between the rotating shaft 1 and the fixed arm and is used to detect the rotation angle of the rotating shaft 1 relative to the fixed arm, thereby obtaining the rotation angle of the load arm 2 relative to the fixed arm. Of course, in other embodiments, the angular displacement sensor 13 may not be provided, and the rotation angle of the load arm 2 relative to the fixed arm may be obtained by other means.

[0044] Load arm 2 is used to mount the rear load. The gravitational torque exerted by the combined gravity of load arm 2 and the rear load on the rotating shaft 1 can affect the doctor's operating feel. Therefore, a drive unit and elastic element 12 are provided to balance the gravitational torque. All gravitational torques provided below refer to the gravitational torque exerted by the combined gravity of load arm 2 and the rear load on the rotating shaft 1.

[0045] The drive unit is mounted on the fixed arm, and its output end is connected to the rotating shaft 1. Specifically, the drive unit is a motor 4, which is fixedly connected to the fixed arm. The output end of the motor 4, i.e., the output shaft, is connected to the rotating shaft 1 via a bevel gear set. The bevel gear set includes a first bevel gear 5 and a second bevel gear 6. The first bevel gear 5 is sleeved on the rotating shaft 1 and is coaxially and fixedly connected to the rotating shaft 1. The second bevel gear 6 is coaxially and fixedly connected to the output shaft of the motor 4. The bevel gear set transmits the output torque of the motor 4, thereby forming a driving torque acting on the rotating shaft 1.

[0046] The first end of the elastic element 12 is connected to the fixed arm, and the second end is eccentrically connected to the rotating shaft 1 or to the equivalent shaft 10 of the rotating shaft 1. The equivalent shaft 10 of the rotating shaft 1 is a shaft that is parallel to and rotates synchronously with the rotating shaft 1. Synchronous rotation here means that the equivalent shaft 10 rotates exactly one revolution when the rotating shaft 1 rotates one revolution.

[0047] The elastic element 12 has an elastic force that contracts in the straight line direction of its first and second ends. The elastic force of the elastic element 12 generates an elastic torque acting on the rotating shaft 1. This elastic torque, in conjunction with the driving torque of the drive unit, is used to balance the gravitational torque acting on the rotating shaft 1 by the overall gravity of the load arm 2 and the rear load. That is, the elastic torque corresponding to the elastic force of the elastic element 12 can balance a portion of the gravitational torque, and the remaining gravitational torque is then balanced by the driving torque corresponding to the drive unit. The combined action of the elastic element 12 and the drive unit can balance all the gravitational torque, making the operation feel light and responsive for the doctor. Moreover, since a portion of the gravitational torque in this embodiment is balanced by the elastic element 12, the power requirement for the motor is reduced, allowing the use of a motor with smaller power, smaller size, and smaller weight compared to existing technologies.

[0048] Meanwhile, during the entire stroke of the load arm 2 rotating relative to the fixed arm, the elastic torque generated by the elastic element 12, the gravitational torque generated by the overall gravity of the load arm 2 and the load at the rear end, and the driving torque generated by the drive unit work together to enable the load arm 2 to maintain balance at any position in the stroke, that is, it can stop at any position without the action of external force.

[0049] The second end of the elastic element 12 is eccentrically connected to the rotating shaft 1 or its equivalent shaft 10 via the auxiliary element 9. Specifically, one end of the auxiliary element 9 is connected to the rotating shaft 1 or its equivalent shaft 10, and the other end is provided with a connecting post arranged parallel to the rotating shaft 1; the second end of the elastic element 12 is connected to the first end of a pull rope 11, the second end of the pull rope 11 forms a loop and is fitted onto the connecting post, and the pull rope 11 is in a taut state.

[0050] Since the second end of the elastic element 12 also rotates around the rotating shaft 1 or its equivalent axis 10 once when the rotating shaft 1 rotates one revolution, the connection between the pull rope 11 and the connecting post will pass above the rotating shaft 1 or its equivalent axis 10. Therefore, the auxiliary element 9 needs to be connected to the end face of the rotating shaft 1 or the end face of its equivalent axis 10 to prevent the movement of the pull rope 11 from interfering with the rotating shaft 1 or its equivalent axis 10.

[0051] Since angular displacement sensors 13 and load arms 2 are already installed on both end faces of the rotating shaft 1 in this embodiment, an equivalent shaft 10 is required. The auxiliary component 9 is installed on the axial end face of the equivalent shaft 10. Specifically, the axis of the equivalent shaft 10 and the axis of the rotating shaft 1 are located in the same vertical plane, and the equivalent shaft 10 is located on the side of the rotating shaft 1 closest to the motor 4. The equivalent shaft 10 is rotatably connected to the fixed arm, and the rotating shaft 1 and the equivalent shaft 10 are connected by a spur gear set. The spur gear set includes a first spur gear 7 and a second spur gear 8. The first spur gear 7 is sleeved on the rotating shaft 1 and coaxially fixedly connected to it. The second spur gear 8 is sleeved on the equivalent shaft 10 and coaxially fixedly connected to it. The first spur gear 7 and the second spur gear 8 mesh. The auxiliary component 9 converts the elastic force of the elastic element 12 into a torque acting on the equivalent shaft 10. This torque is transmitted through the spur gear set to form an elastic torque acting on the rotating shaft 1. Preferably, the line containing the elastic force of the elastic element 12 is perpendicular to or perpendicular to the axis of the rotation shaft 1, so that the elastic element 12 will not generate a component force along the axis of the rotation shaft 1.

[0052] Of course, in other embodiments, if the angular displacement sensor 13 does not need to be installed on the rotating shaft 1 or the angular displacement sensor is hollow (i.e., the rotating shaft 1 can pass through the angular displacement sensor so that the angular displacement sensor does not occupy the end face position), then the equivalent shaft 10 and the spur gear set can be omitted, and the auxiliary component 9 can be directly set at the second axial end of the rotating shaft 1 (that is, the end that is not connected to the load arm 2). Alternatively, the auxiliary component 9 and the angular displacement sensor 13 can be interchanged, that is, the angular displacement sensor 13 can be installed on the equivalent shaft 10 and the auxiliary component 9 can be installed at the second axial end of the rotating shaft 1; however, with such a setting, the volume of the entire robotic arm joint will generally be larger than that in this embodiment.

[0053] The positions of the auxiliary component 9 and the corresponding positions of the load arm 2 are as follows: Figures 2 to 4 As shown in the figure, when the rope 11 is in a vertical position (that is, when the connecting column on the auxiliary component 9 is at its top and bottom), the load arm 2 is not in a vertical position. This is because the lever arm of the elastic torque corresponding to the elastic component 12 is much shorter than the lever arm of the gravitational torque. Therefore, at equilibrium, the elastic force of the elastic component 12 is much greater than the gravitational force. If the two forces meet in a vertical position, according to the limit principle, the lever arms are approximately equal, but the magnitudes of the two forces differ by several times. This will cause the elastic torque corresponding to the elastic component 12 to be much greater than the gravitational torque before and after crossing the vertical point, breaking the balance and generating a large angular acceleration, which is not conducive to a smooth transition. Therefore, when the direction of the elastic force of the elastic component 12 is vertical, the direction of the lever arm of the gravitational torque is not vertical.

[0054] The elastic element 12 can be a spring, but in other embodiments, other elastic components such as elastic columns can be used; this is not a limitation. The two ends of the spring are connected to the pull rope 11 and the fixed arm, respectively. The position between the spring and the fixed arm is adjustable, thereby adjusting the magnitude of the spring's elastic force in the initial state of the robotic arm joint.

[0055] Specifically, the fixed arm may include a first housing 3 and a second housing. The motor 4 is located inside the first housing 3, while the spring, equivalent shaft 10, auxiliary components 9, etc., may be located inside the second housing. An adjusting block 14 is connected to one end of the spring that connects to the fixed arm. Multiple mounting positions are arranged along the length of the fixed arm on the first housing 3, and the adjusting block 14 is mounted on one of these mounting positions using fasteners. By changing the mounting position of the adjusting block 14, the elastic force of the spring in the initial state of the robotic arm joint can be adjusted.

[0056] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they shall still fall within the protection scope of the present invention.

Claims

1. A reversible, balancing robotic arm joint assisted by elastic force, characterized in that, include: Rotation axis; A fixed arm is rotatably connected to the rotating shaft, and its rotation axis coincides with the axis of the rotating shaft; the fixed arm is provided with a driving part, and the output end of the driving part is connected to the rotating shaft; A load arm is fixedly connected to the rotating shaft and rotatably connected to the fixed arm about the axis of the rotating shaft; the load arm is used to mount the rear load. The elastic element has a first end connected to the fixed arm and a second end eccentrically connected to the rotating shaft or to the equivalent axis of the rotating shaft, wherein the equivalent axis of the rotating shaft is an axis that is parallel to and rotates synchronously with the rotating shaft. The elastic element has an elastic force that contracts in the straight direction of its first and second ends. The elastic force of the elastic element generates an elastic torque that acts on the rotating shaft. The elastic torque, in conjunction with the driving torque of the drive unit, is used to balance the gravitational torque of the overall gravity of the load arm and the rear load acting on the rotating shaft. Wherein, when the elastic force of the elastic element is in the vertical direction, the lever arm of the gravitational torque is in the non-vertical direction.

2. The elastic force-assisted reversible balancing robotic arm joint according to claim 1, characterized in that, The second end of the elastic element is connected to the equivalent axis of the rotating shaft; The axis of the equivalent axis and the axis of the rotation axis are located in the same vertical plane, and the equivalent axis is located on the side of the rotation axis closer to the drive unit.

3. The elastic force-assisted reversible balancing robotic arm joint according to claim 1, characterized in that, The line containing the elastic force of the elastic element is perpendicular to or on a different plane from the axis of the rotation shaft.

4. The elastic force-assisted reversible balancing robotic arm joint according to claim 1, characterized in that, The second end of the elastic element is eccentrically positioned with respect to the rotating shaft or the equivalent axis of the rotating shaft via an auxiliary component; One end of the auxiliary component is connected to the rotating shaft or the equivalent axis of the rotating shaft, and the other end is provided with a connecting post arranged parallel to the rotating shaft; the second end of the elastic component is connected to the first end of a pull rope, the second end of the pull rope forms a rope sleeve fitted on the connecting post, and the pull rope is in a straight state.

5. The elastic force-assisted reversible balancing robotic arm joint according to claim 4, characterized in that, The auxiliary component is connected to the end face of the rotating shaft or its equivalent axis to prevent the movement of the pull rope from interfering with the rotating shaft or its equivalent axis.

6. The elastic force-assisted reversible balancing robotic arm joint according to claim 1 or 4, characterized in that, The second end of the elastic element is eccentrically connected to the equivalent axis of the rotating shaft, and the equivalent axis is rotatably connected to the fixed arm; The rotating shaft and the equivalent shaft are connected by a spur gear set, which includes a first spur gear and a second spur gear. The first spur gear is sleeved on the rotating shaft and coaxially and fixedly connected to the rotating shaft. The second spur gear is sleeved on the equivalent shaft and coaxially and fixedly connected to the equivalent shaft. The first spur gear and the second spur gear mesh.

7. The elastic force-assisted reversible balancing robotic arm joint according to claim 1, characterized in that, The drive unit is a motor, which is fixedly connected to the fixed arm, and the output shaft of the motor is connected to the rotating shaft through a bevel gear set; The bevel gear set includes a first bevel gear and a second bevel gear. The first bevel gear is sleeved on the rotating shaft and is coaxially and fixedly connected to the rotating shaft. The second bevel gear is coaxially and fixedly connected to the output shaft of the motor.

8. The elastic force-assisted reversible balancing robotic arm joint according to claim 1, characterized in that, The first axial end of the rotating shaft is connected to the load arm, and an angular displacement sensor is provided between the second axial end of the rotating shaft and the fixed arm. The angular displacement sensor is used to detect the rotation angle of the rotating shaft relative to the fixed arm. The second end of the elastic element is eccentrically connected to the equivalent axis of the rotating shaft.

9. The elastic force-assisted reversible balancing robotic arm joint according to claim 1, characterized in that, The elastic element is a spring.

10. The elastic force-assisted reversible balancing robotic arm joint according to claim 9, characterized in that, The connection position between the first end of the elastic element and the fixed arm is adjustable to adjust the magnitude of the elastic force of the elastic element when the robotic arm joint is in its initial state.

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