A serial manipulator

Abstract

An embodiment of this specification provides a serial manipulator, which includes a manipulator body and a gravity balance component; the manipulator body includes a base, a first link, and a link assembly; the base, the first link, and the link assembly are sequentially rotatably connected through a first joint and a second joint; the gravity balance component includes at least one balance mechanism, and the at least one balance mechanism can generate at least one balance torque on the second joint; the at least one balance torque is at least used to balance the gravity torque generated by the gravity of the link assembly on the second joint, so that the link assembly is in a completely balanced state. The serial manipulator provided by the embodiment of this specification can achieve complete gravity balance in any posture within its motion space, has a simple and compact structure, and has good dexterity, operation accuracy, and operation comfort.

Description

Technical Field

[0001] This specification relates to the field of robotic arms, and particularly to a serial robotic arm. Background Art

[0002] Robotic arms, as a new type of human-computer interaction approach, are widely used in industries, medical fields, etc. Among them, serial robotic arms are a relatively common type of robotic arm, and operators can operate serial robotic arms for industrial production, surgical treatment, etc. For example, a serial robotic arm can be used as a doctor's robotic arm and be an important part of a surgical robot. A doctor can operate the doctor's robotic arm to control the end effector of the surgical robot to complete actions such as cutting, tying knots, and suturing.

[0003] However, when an operator operates a serial robotic arm, the self-gravity of the serial robotic arm will have a negative impact on the dexterity, operation accuracy of the serial robotic arm, and the force feedback to the operator, and it will also cause the operator's muscles to feel fatigued during long-term operation. Therefore, the problem of complete gravity balance usually needs to be considered in the design of robotic arms to eliminate the negative impact brought by the self-gravity of the serial robotic arm. Summary of the Invention

[0004] An embodiment of this specification provides a serial robotic arm, including: a robotic arm body and a gravity balance component; the robotic arm body includes a base, a first link, and a link assembly; the base, the first link, and the link assembly are sequentially rotationally connected through a first joint and a second joint; the gravity balance component includes at least one balance mechanism, and the at least one balance mechanism can generate at least one balance moment on the second joint; the at least one balance moment is at least used to balance the gravity moment generated by the gravity of the link assembly on the second joint, so that the link assembly is in a completely balanced state.

[0005] In some embodiments, the link assembly includes a second link and a third link rotatably connected by a third joint; the gravity balance assembly further includes a first balance link and a second balance link; a portion of the first balance link, the second balance link, the second link, and the third link are rotatably connected to form a parallelogram structure; wherein one end of the second link is rotatably connected to one end of the first link and the first balance link through the second joint, and the other end is rotatably connected to the third link through the third joint; one end of the first balance link is rotatably connected to the second link through the second joint, the other end of the first balance link is rotatably connected to one end of the second balance link, and the other end of the second balance link is rotatably connected to the third link; through the parallelogram structure, the angle of rotation of the third link around the third joint can be jointly determined by the angle of rotation of the second link around the second joint and the angle of rotation of the first balance link around the second joint.

[0006] In some embodiments, the gravity balance assembly includes a first balance mechanism and a second balance mechanism; the first balance mechanism and the second balance mechanism can respectively generate a first balance torque and a second balance torque on the second joint, and the first balance torque and the second balance torque are used to balance the gravity torque generated on the second joint by the gravity of the second link, the third link, the first balance link, and the second balance link; wherein the first balance torque is at least related to the angle of rotation of the first balance link around the second joint, and the second balance torque is at least related to the angle of rotation of the second link around the second joint.

[0007] In some embodiments, the second joint includes a first rotating half shaft and a second rotating half shaft arranged opposite to each other; one end of the second link is fixedly connected to the first rotating half shaft; one end of the first balance link is fixedly connected to the second rotating half shaft.

[0008] In some embodiments, the first balance mechanism includes a first balance spring, a first balance rope, a first guiding mechanism, and a second guiding mechanism; one end of the first balance spring is fixedly connected to the first connecting rod, and the other end of the first balance spring is fixedly connected to one end of the first balance rope; the first guiding mechanism is arranged on the first connecting rod to guide the other end of the first balance rope to the second guiding mechanism, and the second guiding mechanism is arranged on the first balance connecting rod to guide the other end of the first balance rope to be connected to the first rotating half shaft; the first balance spring is in an extended state under the traction of the first balance rope and generates a first spring tension, and the first spring tension can generate the first balance moment on the second joint; wherein, the elongation of the first balance spring is the same as the distance between the first guiding mechanism and the second guiding mechanism.

[0009] In some embodiments, the first balance mechanism further includes a first balance rope fixing and tightening mechanism, and the first balance rope fixing and tightening mechanism is used to fixedly tighten the other end of the first balance rope on the first rotating half shaft.

[0010] In some embodiments, the position of the first guiding mechanism on the first connecting rod and / or the position of the second guiding mechanism on the first balance connecting rod are adjustable.

[0011] In some embodiments, the second balance mechanism includes a second balance spring, a second balance rope, a third guiding mechanism, and a fourth guiding mechanism; one end of the second balance spring is fixedly connected to the second connecting rod, and the other end of the second balance spring is fixedly connected to one end of the second balance rope. The third guiding mechanism is arranged on the first connecting rod to guide the other end of the second balance rope to the fourth guiding mechanism, and the fourth guiding mechanism is arranged on the second connecting rod to guide the other end of the second balance rope to be connected to the second connecting rod or the second rotating half shaft. The second balance spring is in an extended state under the traction of the second balance rope and generates a second spring tension, and the second spring tension can generate the second balance moment on the second joint; wherein, the elongation of the second balance spring is the same as the distance between the third guiding mechanism and the second fourth guiding mechanism.

[0012] In some embodiments, the second balance mechanism further includes a second balance rope fixing and tightening mechanism, and the second balance rope fixing and tightening mechanism is used to fixedly tighten the other end of the second balance rope on the second connecting rod or the second rotating half shaft.

[0013] In some embodiments, the position of the third guiding mechanism on the first connecting rod and / or the position of the fourth guiding mechanism on the second connecting rod are adjustable.

[0014] In some embodiments, the spring constant of the first balance spring wherein, K1 is the spring constant of the first balance spring, G2 is the gravity of the third link, is the distance between the third joint and the centroid of the third link, G3 is the gravity of the first balance link, is the distance between the second joint and the centroid of the first balance link, G4 is the gravity of the second balance link, L AC is the length of the first balance link, L AE is the distance between the first guiding mechanism and the second joint, L AF is the distance between the second guiding mechanism and the second joint.

[0015] In some embodiments, the spring constant of the second balance spring wherein, K2 is the spring constant of the first balance spring, G1 is the gravity of the second link, is the distance between the second joint and the centroid of the second link, G2 is the gravity of the third link, L AB is the length of the second link, G4 is the gravity of the second balance link, is the distance between the connection point between the first balance link and the second balance link and the centroid of the second balance link, L AG is the distance between the third guiding mechanism and the second joint, L AH is the distance between the fourth guiding mechanism and the second joint.

[0016] In some embodiments, the link assembly includes a second link, and the second link is rotatably connected to the first link through the second joint; the gravity balance assembly includes a balance mechanism, and the balance mechanism can generate a balance moment on the second joint, and the balance moment is used to balance the gravity moment generated by the gravity of the second link on the second joint.

[0017] In some embodiments, the balance mechanism includes a balance spring, a balance rope, a first guiding mechanism, and a second guiding mechanism; one end of the balance spring is fixedly connected to the first link, the other end of the balance spring is fixedly connected to one end of the balance rope, the first guiding mechanism is disposed on the first link for guiding the other end of the balance rope to the second guiding mechanism, and the second guiding mechanism is disposed on the second link for guiding and connecting the other end of the balance rope to the second link; the balance spring is in an extended state under the traction of the balance rope and generates a spring tension, and the spring tension can generate the balance torque on the second joint; wherein, the elongation of the balance spring is the same as the distance between the first guiding mechanism and the second guiding mechanism.

[0018] In some embodiments, the spring constant of the balance spring Wherein, K is the spring constant of the balance spring, G1 is the gravity of the second link, is the distance between the second joint and the center of gravity of the second link, L AB is the distance between the first guiding mechanism and the second joint, L AC is the distance between the second guiding mechanism and the second joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] This specification will be further described by way of exemplary embodiments, which will be described in detail through the accompanying drawings. These embodiments are not restrictive. In these embodiments, the same numbers represent the same structures, wherein:

[0020] Figure 1 is the front view of a serial manipulator with two links in the link assembly according to some embodiments of this specification;

[0021] Figure 2 is the rear view of a serial manipulator with two links in the link assembly according to some embodiments of this specification;

[0022] Figure 3 is Figure 1 a cross-sectional view along the A-A direction;

[0023] Figure 4 is Figure 1 a partial enlarged view of the area where the first balance torque is generated in ;

[0024] Figure 5 is Figure 2 a partial enlarged view of the area where the second balance torque is generated in ;

[0025] Figure 6 is Figure 1Schematic diagram of forces when the second link and the first balance link shown rotate by a certain angle around the second joint;

[0026] Figure 7 is Figure 2 Schematic diagram of forces when the second link and the first balance link shown rotate by a certain angle around the second joint;

[0027] Figure 8 is a schematic structural diagram of a serial manipulator in which the link assembly shown includes only one link according to some embodiments of this specification;

[0028] Figure 9 is Figure 8 Schematic diagram of forces when the second link shown rotates by a certain angle around the second joint.

[0029] Reference numerals: 100 is a serial manipulator; 2 is a base; 3 is a link assembly; 31 is a third joint; 32 is a second link; 33 is a third link; 4 is a first joint; 5 is a second joint; 51 is a first rotating half shaft; 52 is a second rotating half shaft; 6 is a first balance link; 61 is a first fixing block; 62 is a bolt; 7 is a second balance link; 8 is a first balance mechanism; 81 is a first balance spring; 82 is a first balance rope; 83 is a first guiding mechanism; 831 is a first guiding wheel; 832 is a first bracket; 84 is a second guiding mechanism; 85 is a first fixing and tightening mechanism; 851 is a first tightening wheel; 852 is a first tightening pressing block; 9 is a second balance mechanism; 91 is a second balance spring; 92 is a second balance rope; 93 is a third guiding mechanism; 94 is a fourth guiding mechanism; 95 is a second fixing and tightening mechanism; 200 is a serial manipulator; 10 is a balance mechanism; 11 is a balance spring; 12 is a balance rope; 13 is a first guiding mechanism; 14 is a second guiding mechanism. Detailed implementation manners

[0030] To more clearly illustrate the technical solutions of the embodiments of this specification, the accompanying drawings required for description in the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some examples or embodiments of this specification. For those of ordinary skill in the art, without creative efforts, this specification can also be applied to other similar scenarios based on these drawings. Unless obvious from the language context or otherwise stated, the same reference numerals in the figures represent the same structure or operation.

[0031] It should be understood that the "system", "device", "unit" and / or "module" used herein is a method for distinguishing different components, elements, parts, portions or assemblies at different levels. However, if other words can achieve the same purpose, the said words can be replaced by other expressions.

[0032] As shown in this specification and the claims, unless the context clearly indicates otherwise, words such as "a", "an", "one" and / or "the" are not specifically singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of the clearly identified steps and elements, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0033] As an important part of robot systems such as industrial robots and surgical robots, robotic arms usually include three types: serial robotic arms, parallel robotic arms, and hybrid robotic arms. In practice, the robotic arms we commonly see are mostly serial robotic arms. For example, in surgical treatment, doctors can control the end effector of the surgical robot by operating the doctor's robotic arm to complete actions such as cutting, tying knots, and suturing. Among them, the doctor's robotic arm is mostly a serial robotic arm.

[0034] However, if there is a problem that the gravity of the serial robotic arm cannot be completely balanced, when the operator operates the serial robotic arm, the self-gravity of the serial robotic arm and the inertial force generated during its movement will cause fatigue to the operator, and will also reduce the operation accuracy, dexterity of the serial robotic arm and the inaccurate force feedback to the operator. Among them, the complete balance of the gravity of the serial robotic arm can be understood as that in any posture within its movement space, for example, when the moving component (such as a connecting rod) in the serial robotic arm rotates to a certain position and the driving force acting on it disappears, the gravity of the moving component can be balanced so that the moving component will not rotate again due to its own gravity, so that the moving component can stay in the current position, so that the serial robotic arm can maintain the corresponding posture after the driving force driving its movement disappears. Specifically, the complete balance of gravity can be achieved by balancing the gravitational moment generated by the gravity of the connecting rod in the serial robotic arm on the joint, and balancing the gravitational moment generated by the gravity of the connecting rod in the serial robotic arm on the joint can be achieved by canceling the gravitational moment with a moment of equal magnitude and opposite direction generated on the same joint.

[0035] In some embodiments, the complete balance of the gravity of the serial robotic arm can be achieved by means of a counterweight design. For example, appropriate counterweight blocks can be added in the symmetric direction of the connecting rod of the serial robotic arm relative to the joint. The moment generated by the gravity of the counterweight block on the joint can be used to balance the moment generated by the gravity of the connecting rod on the joint, so as to achieve the complete balance of the gravity of the serial robotic arm. However, adding counterweights will increase the overall mass and inertial force of the serial robotic arm, and to a certain extent, will also increase the spatial size and structural complexity of the serial robotic arm, which will lead to varying degrees of reduction in the dexterity, operation comfort, and operation accuracy of the serial robotic arm.

[0036] In some embodiments, the gravity of the serial manipulator can be completely balanced by means of motor compensation. For example, by the motor outputting a reverse torque to balance the gravity moment generated by the gravity of each link of the serial manipulator on the corresponding joint, so as to achieve the complete gravity balance of the serial manipulator. However, the method of motor compensation will consume a large amount of torque of the motor, resulting in an oversized motor selection, and may also cause the force fed back by the serial manipulator to the operator to be inaccurate.

[0037] The embodiments of the present specification provide a serial manipulator which uses the spring tension generated when the spring is in the extended state to generate a balancing moment on the joint in the serial manipulator to balance the gravity moment to be balanced in the serial manipulator (that is, the gravity moment generated by the gravity of the moving components in the serial manipulator on this joint), so as to achieve the complete gravity balance of the serial manipulator. Among them, when the gravity moment to be balanced changes with the change of the rotation angle of the relevant moving components (such as links) of the serial manipulator, the balancing moment will also change in the same way with the change of the rotation angle of the relevant moving components of the serial manipulator, so as to ensure that the serial manipulator can achieve complete gravity balance when the relevant moving components rotate at any angle. In addition, the serial manipulator provided by the embodiments of the present specification realizes complete gravity balance by making the spring in the extended state, with a simple and compact structure, the spring being light in weight, not adding too much inertial force to affect the operation accuracy and operation comfort of the serial manipulator, and not interfering with the movement of the serial manipulator.

[0038] The serial manipulator provided by the embodiments of the present specification may include a manipulator body and a gravity balance assembly. Among them, the manipulator body includes a base, a first link and a link assembly. The base, the first link and the link assembly are rotationally connected through a first joint and a second joint, that is, the first link can rotate axially relative to the base around the first joint, and the link assembly can rotate relative to the first link around the second joint. The gravity balance assembly may include at least one balance mechanism. The at least one balance mechanism can generate at least one balancing moment on the second joint, and the at least one balancing moment can at least be used to balance the gravity moment generated by the gravity of the link assembly on the second joint, so that the link assembly is completely balanced. Among them, the balance mechanism includes a spring, and the spring can be made in the extended state to generate a spring tension, so as to generate a balancing moment on the second joint. In addition, the balance mechanism can also make the elongation of the spring change with the change of the rotation angle of the link assembly, so that the balancing moment can also change in the same way as the gravity moment with the change of the rotation angle of the link assembly, so that when the link assembly rotates at any angle, it can be in a completely balanced state.

[0039] In some embodiments, the complete balance of the link assembly can be understood as that when the serial manipulator is not under the action of external forces, the link assembly can maintain balance in any posture in the motion space (for example, the link assembly rotates by any angle), that is, when the link assembly rotates to a certain position, in the case where the external force (for example, the driving force received by the link assembly during rotation) disappears, the link assembly will not rotate due to its own gravity, so that the link assembly can be maintained at the current position.

[0040] It should be noted that since the first link rotates relative to the base around the first joint and the gravity of the first link acts on the base, the gravity of the first link does not need to be balanced (that is, the gravity of the first link does not generate a gravity moment on the second joint). When the gravity of the link assembly is balanced and in a complete balance, the gravity of the serial manipulator can be completely balanced.

[0041] In some embodiments, in order to meet the design requirements of different degrees of freedom of the serial manipulator, the link assembly may include one link or two links rotatably connected through a third joint. For example, when the link assembly includes one link, the serial manipulator has three degrees of freedom and is usually applied in industrial robot systems. Another example is that when the link assembly includes two links, the serial manipulator has six degrees of freedom and is widely applied in robot systems such as industrial robots and surgical robots.

[0042] In some embodiments, for the case where the link assembly includes one link or two links rotatably connected through a third joint, correspondingly, the number of balance mechanisms in the gravity balance assembly can be one or two. In some embodiments, when the gravity balance assembly includes one balance mechanism, it can generate a balance moment to balance the gravity moment generated by the gravity of the link assembly (including only the first link) on the second joint. When the gravity balance assembly includes two balance mechanisms, considering that the gravity of the link assembly also generates a gravity moment on the third joint in the link assembly, the gravity balance assembly further includes a balance link to transfer the gravity moment at the third joint to the second joint. Therefore, the two balance mechanisms in the gravity balance assembly can generate two balance moments to balance the gravity of the link assembly (including two links) and the gravity moment generated by the balance link (for example, the balance link described below) in the gravity balance assembly on the second joint.

[0043] In some embodiments, in addition to the link, the link assembly may further include an actuator rotatably connected to the end of the link (for example, a welding torch in a welding robot, a surgical instrument of a surgical robot, etc.). Therefore, the complete balance of the link assembly may include that the gravity moments generated by the gravity of the link and the actuator in the link assembly on the second joint are balanced (or offset) by the corresponding balance moments.

[0044] The following will separately and in detail describe the connecting rod assembly provided in the embodiments of this specification, which includes two connecting rods, and the serial robotic arm that includes only one connecting rod, as well as their balancing principles, in conjunction with the accompanying drawings.

[0045] Figure 1 is the front view of the serial robotic arm with a connecting rod assembly including two connecting rods according to some embodiments of this specification. Figure 2 is the rear view of the serial robotic arm with a connecting rod assembly including two connecting rods according to some embodiments of this specification. Figure 3 is Figure 1 a cross-sectional view taken along the A-A direction.

[0046] In some embodiments, in combination with Figure 1 , Figure 2 and Figure 3 as shown, the serial robotic arm 100 includes a robotic arm body and a gravity balancing assembly. The robotic arm body includes a base 1, a first connecting rod 2, and a connecting rod assembly 3. The first connecting rod 2 is rotatably connected to the base 1 through a first joint 4, such that the first connecting rod 2 can rotate relative to the base 1 about the axis direction of the first joint 4 (for example, Figure 1 the Z-axis direction shown or a direction parallel to the Z-axis). The connecting rod assembly 3 is rotatably connected to the first connecting rod 2 through a second joint 5, such that the connecting rod assembly 3 can rotate relative to the first connecting rod 2 about the axis direction of the second joint 5 (for example, Figure 1 the X-axis direction shown or a direction parallel to the X-axis). Among them, the connecting rod assembly 3 may include a second connecting rod 32 and a third connecting rod 33 that are rotatably connected through a third joint 31, and the third connecting rod 32 can rotate relative to the second connecting rod 32 about the axis direction of the third joint 31 (for example, Figure 1 the X-axis direction shown or a direction parallel to the X-axis). It should be noted that the axis directions of both the second joint 5 and the third joint 6 are Figure 1 the direction perpendicular to the paper surface, that is, Figure 1 the X-axis direction shown or a direction parallel to the X-axis.

[0047] Continuing to refer to Figure 1 , Figure 2 and Figure 3 as shown, the gravity balancing assembly may include a first balancing connecting rod 6 and a second balancing connecting rod 7. Among them, part or all of the first balancing connecting rod 6, the second balancing connecting rod 7, the second connecting rod 32, and the third connecting rod 33 may be rotatably connected to form a parallelogram structure.

[0048] Specifically, one end of the second link 32 is rotatably connected to one end of the first link 2 and the first balance link 6 through the second joint 5; the other end of the second link 32 is rotatably connected to the third link 33 through the third joint 31. The other end of the first balance link 6 is rotatably connected to one end of the second balance link 7, and the other end of the second balance link 7 is rotatably connected to the third link 33. Among them, the rotations of the second link 32 and the first balance link 6 around the second joint 5 are independent of each other.

[0049] In some embodiments, the length of the first balance link 6 may be less than or equal to the length of the third link 33, that is, the length of the first balance link 6 is the same as the length of the third link 33 between the second joint 5 and the connection point of the second balance link 7 and the third link 33 (this length is less than or equal to the length of the third link 33), and the length of the second balance link 7 is the same as the length of the second link 32, so that the structure formed by the rotational connections between some or all of the first balance link 6, the second balance link 7, the second link 32, and the third link 33 is a parallelogram structure.

[0050] Through the parallelogram structure formed by the rotational connections between some or all of the first balance link 6, the second balance link 7, the second link 32, and the third link 33, the angle by which the third link 33 rotates around the third joint 31 can be jointly determined by the angle by which the second link 32 rotates around the second joint 5 and the angle by which the first balance link 6 rotates around the second joint 5. That is, when the angles by which the second link 32 rotates around the second joint 5 and the first balance link 6 rotates around the second joint 5 are determined, the angle by which the third link 33 rotates around the third joint 31 can also be determined accordingly. Furthermore, when the gravitational moment at the second joint 5 (i.e., the gravitational moment generated by the first balance link 6, the second balance link 7, the second link 32, and the third link 33 on the second joint) is balanced (or cancelled out), the gravitational moment at the third joint 31 (i.e., the gravitational moment generated by the first balance link 6, the second balance link 7, the second link 32, and the third link 33 on the second joint) is also in a balanced state. That is to say, the gravitational moment at the third joint is transferred to the second joint 5 through the parallelogram structure. Therefore, to achieve complete gravitational balance of the serial manipulator 100, it is necessary to balance the gravitational moment at the second joint 5.

[0051] In addition, through the parallelogram structure, a driving mechanism (e.g., a motor) does not need to be provided at the third joint 31 to drive the rotation of the third link 33. Instead, only a driving mechanism needs to be provided at the second joint 5 to drive the rotation of the second link 32 and the first balance link 6. The rotation of the second link 32 and the first balance link 6 drives the third link 33 to rotate around the third joint 31 through the parallelogram structure, which can make the structure of the serial manipulator 100 more compact and can solve the problem of complex wiring of the driving mechanism of the serial manipulator 100 to a certain extent.

[0052] In some embodiments, the rotation of the second link 32 and the third link 33 can also be used to drive the first balance link 6 to rotate around the second joint 5 through the parallelogram structure. That is, a driving mechanism for driving the rotation of the third link 33 is provided at the third joint 31, and a driving mechanism for only driving the rotation of the second link 32 is provided at the second joint 5. At this time, the rotation angle of the first balance link 6 around the second joint 5 can be jointly determined by the rotation angle of the third link 33 around the third joint 31 and the rotation angle of the second link 32 around the second joint 5.

[0053] In some embodiments, the rotation of the third link 33 and the first balance link 6 can also be used to drive the second link 32 to rotate around the second joint 5 through the parallelogram structure. That is, a driving mechanism for driving the rotation of the third link 33 is provided at the third joint 31, and a driving mechanism for only driving the rotation of the first balance link 6 is provided at the second joint 5. At this time, the rotation angle of the second link 32 around the second joint 5 can be jointly determined by the rotation angle of the third link 33 around the third joint 31 and the rotation angle of the first balance link 6 around the second joint 5.

[0054] To balance the gravity moment at the second joint 5 to achieve the complete balance of the serial manipulator 100, as Figure 2 shown, the gravity balance assembly may include a first balance mechanism 8 and a second balance mechanism 9. The first balance mechanism 8 and the second balance mechanism 9 can respectively generate a first balance moment and a second balance moment on the second joint 5. The first balance moment and the second balance moment can be jointly used to balance the gravity moment generated by the second link 32, the third link 33, the first balance link 6, and the second balance link 7 on the second joint 5, thereby achieving the complete gravity balance of the serial manipulator 100. Specifically, the vector sum of the first balance moment and the second balance moment is equal in magnitude and opposite in direction to the vector sum of the gravity moment generated by the second link 32, the third link 33, the first balance link 6, and the second balance link 7 on the second joint 5, thereby balancing (or canceling) the gravity moment at the second joint 5.

[0055] Since the vector sum of the first balancing moment and the second balancing moment and the gravitational moment generated by the second link 32, the third link 33, the first balancing link 6, and the second balancing link 7 on the second joint 5 will change with the change of the angle of rotation of the second link 32 and the first balancing link 6 around the second joint, in order to ensure that the serial manipulator 100 can achieve complete gravitational balance in any posture within its motion space, that is, when the second link 32 and the first balancing link 6 rotate around the second joint 5 by any angle, the second link 32, the third link 33, the first balancing link 6, and the second balancing link 7 are all in complete balance. The first balancing moment is at least related to the angle of rotation of the first balancing link 6 around the second joint 5, and the second balancing moment is at least related to the angle of rotation of the second link around the second joint 5, so that the first balancing moment and the second balancing moment can also change with the change of the angle of rotation of the second link 32 and the first balancing link 6 around the second joint, so that the vector sum of the first balancing moment and the second balancing moment is always equal in magnitude and opposite in direction to the vector sum of the gravitational moments generated by the second link 32, the third link 33, the first balancing link 6, and the second balancing link 7 on the second joint 5. Regarding the specific relationship between the first balancing moment, the second balancing moment and the gravitational moment at the second joint 5, and the specific relationship between the first balancing moment, the second balancing moment, the gravitational moment at the second joint 5 and the angle of rotation of the second link 32 and the first balancing link 6 around the second joint 5, it can be found elsewhere in this specification (for example, Figure 6 and Figure 7 and its related descriptions).

[0056] In some embodiments, in order to make the rotation of the second link 32 and the first balancing link 6 around the second joint 5 independent of each other, as shown in Figure 3 , the second joint 5 may include a first rotating half shaft 51 and a second rotating half shaft 52 arranged oppositely. Wherein, one end of the second link 32 is fixedly connected to the first rotating half shaft 51, and one end of the first balancing link 6 is fixedly connected to the second rotating half shaft. By setting a certain gap between the first rotating half shaft 51 and the second rotating half shaft 52 in their axial directions or making there be relative rotation between the first rotating half shaft 51 and the second rotating half shaft 52, the rotation of the second link 32 around the second joint 5 and the rotation of the first balancing link 6 around the second joint 5 can be made independent of each other.

[0057] Hereinafter, how the first balancing mechanism and the second balancing mechanism generate the first balancing moment and the second balancing moment respectively will be described in detail.

[0058] As shown in Figure 1 , the first balancing mechanism 8 may include a first balancing spring 81, a first balancing rope 82, a first guiding mechanism 83, and a second guiding mechanism 84. Wherein, one end of the first balancing spring 81 is fixedly connected to the first link 2 and is located on the same side as the first rotating half shaft 51 (Figure 3 On the left side in [reference], the other end of the first balance spring 81 is fixedly connected to one end of the first balance rope 82. The first guiding mechanism 83 is arranged on the first connecting rod 2 to guide the other end of the first balance rope 82 to the second guiding mechanism 84, and the second guiding mechanism 84 is arranged on the first balance connecting rod 6 to guide the other end of the first balance rope 82 to the first rotating half shaft 51, and the other end of the first balance rope 82 is connected to the first rotating half shaft 51.

[0059] In some embodiments, the other end of the first balance rope 82 can be directly fixedly connected to the first rotating half shaft 51. In some embodiments, referring to Figure 1 As shown in [reference], the first balance mechanism 8 may further include a first balance rope fixing and tightening mechanism 85.

[0060] Figure 4 is Figure 1 a partial enlarged view of the area where the first balance moment is generated in [reference].

[0061] As Figure 4 shown in [reference], the first balance rope fixing and tightening mechanism 85 may include a first tightening wheel 851 and a first tightening pressing block 852. Among them, the first tightening wheel 851 can be used to tighten the first balance rope 82, the first tightening pressing block 852 can fix the other end of the first balance rope 82 on the first tightening wheel 851, and both the first tightening wheel 851 and the first tightening pressing block 852 are fixed on the first rotating shaft 51, so as to realize the fixing and tightening of the other end of the first balance rope 82.

[0062] Through the above settings, the first balance spring 81 can be in an extended state under the traction of the first balance rope 82 to generate a first spring tension, and the first spring tension can generate a first balance moment on the second joint 5. Specifically, the part of the first balance rope 82 located between the first guiding mechanism 83 and the second guiding mechanism 84 is subjected to the first spring tension, which can generate a first balance moment on the second joint 5. Among them, the elongation of the first balance spring 81 is the same as the distance between the first guiding mechanism 82 and the second guiding mechanism 83 (or the length of the first balance rope 82 between the first guiding mechanism 82 and the second guiding mechanism 83).

[0063] Referring to Figure 2 as shown in [reference], the second balance mechanism 9 may include a second balance spring 91, a second balance rope 92, a third guiding mechanism 93, and a fourth guiding mechanism 94. Among them, one end of the second balance spring 91 is fixedly connected to the first connecting rod 2 and is located on the same side as the second rotating half shaft 52 ( Figure 3On the right side in (), the other end of the second balance spring 91 is fixedly connected to one end of the second balance rope 92. The third guiding mechanism 93 is arranged on the first connecting rod 2 to guide the other end of the second balance rope 92 to the fourth guiding mechanism 94, and the fourth guiding mechanism 94 is arranged on the second connecting rod 32 to guide the other end of the second balance rope 92 to be connected to the second connecting rod 32. In some embodiments, the fourth guiding mechanism 94 can guide the other end of the second balance rope 92 to be connected to the second rotating half shaft 52.

[0064] In some embodiments, the other end of the second balance rope 92 can be directly fixedly connected to the second connecting rod 32. Figure 5 is Figure 2 A partial enlarged view of the area where the second balance moment is generated in. In some embodiments, in combination with Figure 2 and Figure 5 As shown, the second balance mechanism 9 may further include a second balance rope fixing and tightening mechanism 95.

[0065] The second balance rope fixing and tightening mechanism 95 can be used to fix and tighten the other end of the second balance rope 92 on the second connecting rod 32. In some embodiments, the second balance rope fixing and tightening mechanism 95 may have a similar structure to the first balance rope fixing and tightening mechanism 85. For more descriptions of the second balance rope fixing and tightening mechanism 95, reference can be made to the description of the first balance rope fixing and tightening mechanism 85 above.

[0066] Through the above settings, the second balance spring 91 can be in an extended state under the traction of the second balance rope 92 to generate a second spring tension, and the second spring tension can generate a second balance moment on the second joint 5. Specifically, the part of the second balance rope 92 between the third guiding mechanism 93 and the fourth guiding mechanism 94 will be subjected to the second spring tension to generate a second balance moment on the second joint 5. Among them, the elongation of the second balance spring 91 is the same as the distance between the third guiding mechanism 93 and the fourth guiding mechanism 94 (or the length of the second balance rope 92 between the third guiding mechanism 93 and the fourth guiding mechanism 94).

[0067] In some embodiments, the first guiding mechanism 83, the second guiding mechanism 84, and the third guiding mechanism 93, the fourth guiding mechanism 94 may at least include rotatable guide wheels, and the first balance rope 82 and the second balance rope 92 can be wound around the guide wheels of the corresponding guiding mechanisms to guide their other ends to the corresponding positions.

[0068] In some embodiments, the spring constant of the first balance spring 81 and / or the second balance spring 91 can be selected according to one or more of the relevant parameters of the second link 32, the third link 33, the first balance link 6, and the second balance link 7 (such as gravity, length, etc.) and the distance between the first guiding mechanism 83, the second guiding mechanism 84 and / or the third guiding mechanism 93, the second guiding mechanism 94 and the second joint 5. The specific relationship between the spring constant of the first balance spring 81 and / or the second balance spring 91 and the relevant parameters of the second link 32, the third link 33, the first balance link 6, and the second balance link 7 (such as gravity, length, etc.) and the distance between the first guiding mechanism 83, the second guiding mechanism 84 and / or the third guiding mechanism 93, the second guiding mechanism 94 and the second joint 5 can be found elsewhere in this specification (such as, Figure 6 and Figure 7 and its related descriptions).

[0069] The balance principle will be described in detail below with reference to the force diagram of the serial manipulator 100.

[0070] Figure 6 is Figure 1 the force diagram when the second link and the first balance link rotate by a certain angle around the second joint as shown. Figure 7 is Figure 2 the force diagram when the second link and the first balance link rotate by a certain angle around the second joint as shown.

[0071] As Figure 6 or Figure 7 shown, let the angle of rotation of the second link 32 around the second joint 5 be θ1, and the angle of rotation of the first balance link 6 around the second joint 5 be θ2; the weights of the second link 32, the third link 33, the first balance link 6, and the second balance link 7 are G1, G2, G3, and G4 respectively; the centers of mass of the second link 32, the third link 33, the first balance link 6, and the second balance link 7 are O1, O2, O3, and O4 respectively; the gravitational moments generated by the weights of the second link 32, the third link 33, the first balance link 6, and the second balance link 7 on the second joint 5 are T1, T2, T3, and T4 respectively; A, B, C, and D are the positions of the second joint 5, the third joint 31, the connection point between the first balance link 6 and the second balance link 7, and the connection point between the second balance link 7 and the third link 33 respectively.

[0072] Therefore, the gravitational moment T that the serial manipulator 100 needs to balance is:

[0073] T = T1 + T2 + T3 + T4 (1)

[0074] After calculation, T1, F2, T3, and T4 are respectively:

[0075]

[0076]

[0077]

[0078]

[0079] Among them, is the distance between the centroid of the second joint 5 and the second link 32; L AB is the distance between the second joint 5 and the third joint 31 (i.e., the length of the second link 32); is the distance between the third joint 31 and the centroid of the third link 33; is the distance between the second joint 5 and the centroid of the first balance link 6; is the distance from the connection point between the first balance link 6 and the second balance link 7 to the centroid of the second balance link 7, L AC is the distance between the second joint 5 and the connection point between the first balance link 6 and the second balance link 7 (i.e., the length of the first balance link 6).

[0080] Substituting equations (2), (3), (4), and (5) into equation (1) gives:

[0081]

[0082] Combining like terms in equation (6) gives:

[0083]

[0084] According to equation (7), the gravity moment T to be balanced by the serial manipulator 100 can be divided into a first gravity moment T a and a second gravity moment T b :

[0085]

[0086]

[0087] Furthermore, the first balance moment generated by the first balance mechanism 8 on the second joint 5 can be used to balance the first gravity moment T a , that is, the first balance moment and the first gravity moment T a are equal in magnitude and opposite in direction; the second balance moment generated by the second balance mechanism 9 on the second joint 5 can then be used to balance the second gravity moment T b , that is, the second balance moment and the second gravity moment T b are equal in magnitude and opposite in direction.

[0088] In some embodiments, referring to Figure 6 as shown, let the spring constant of the first balance spring 81 be K1, the elongation be Δx1, the first spring tension generated by the first balance spring 81 under the traction of the first balance rope 82 be F1, the lever arm length of the first spring tension F1 relative to the second joint 5 be h1, and the positions of the first guiding mechanism 83 and the second guiding mechanism 84 be E and F respectively.

[0089] The first balance moment T generated by the first spring tension F1 on the second joint 5 c is as follows:

[0090] T c = F1 × h1 (10)

[0091] where F1 = K1 × Δx1.

[0092] According to the equality of the areas S of the triangles formed by points A, E, and F ΔAEF it can be obtained that:

[0093]

[0094] where L AE is the distance between the second joint 5 and the first guiding mechanism 83; L AF is the distance between the second joint 5 and the second guiding mechanism 84, L EF is the distance between the first guiding mechanism 83 and the second guiding mechanism 84; and L EF = Δx1.

[0095] From equation (11), it can be obtained that:

[0096]

[0097] Therefore, the first balance moment T c is:

[0098]

[0099] From equations (8) and (13), it can be seen that the first balance moment T c and the first gravity moment T a are both related to cosθ2. By making T c = T a , the balance of the first balance moment T c with respect to the first gravity moment T a can be achieved. Furthermore, it can be obtained that:

[0100]

[0101] According to Equation (14), when the serial manipulator 100 is designed, G2, G3, G4, L AC are all constants. Therefore, the positions E and F of the first guiding mechanism 83 and the second guiding mechanism 84 can be reasonably set and the spring constant K1 of the first balance spring 81 can be selected according to G2, G3, G4, L AC In some embodiments, when the positions E and F of the first guiding mechanism 83 and the second guiding mechanism 84 are determined, a suitable spring can be selected as the first balance spring 81 according to Equation (14), that is, the spring constant of the first balance spring 81

[0102] In some embodiments, it can be seen from Equation (13) that when there is a deviation between the magnitude of the first balance torque T

[0103] and the magnitude of the first gravity torque T c the magnitude of the first balance torque T a can be adjusted by adjusting the positions of the first guiding mechanism 83 and / or the second guiding mechanism 84 so that the magnitude of the first balance torque T c is exactly equal to the magnitude of the first gravity torque T c to ensure that the first balance torque T a can completely balance the first gravity torque T c a .

[0104] Furthermore, the position E of the first guiding mechanism 83 on the first link 2 and / or the position F of the second guiding mechanism 84 on the first balance link 6 can be made adjustable. In some embodiments, the position E of the first guiding mechanism 83 on the first link 2 can be made adjustable, and the position F of the second guiding mechanism 84 on the first balance link 6 can be made non-adjustable. In some embodiments, the position E of the first guiding mechanism 83 on the first link 2 can be made non-adjustable, and the position F of the second guiding mechanism 84 on the first balance link 6 can be made adjustable. In some embodiments, the position E of the first guiding mechanism 83 on the first link 2 and the position F of the second guiding mechanism 84 on the first balance link 6 can both be made adjustable.

[0105] For example only, such as Figure 5 ​As shown, the position E of the first guiding mechanism 83 on the first connecting rod 2 is adjustable, and the position F of the second guiding mechanism 84 on the first balance connecting rod 6 is not adjustable. Specifically, the first guiding mechanism 83 may include a first guiding wheel 831 and a first bracket 832. The first bracket 832 is fixedly connected to the first connecting rod 2, and the first guiding wheel 831 is rotatably connected to the first bracket. The second guiding mechanism 84 may include a second guiding wheel 841 and a second slider 842. The second guiding wheel 841 is rotatably connected to the second slider 842, and the second slider 842 is slidably connected to the first balance connecting rod 6.

[0106] In some embodiments, a first fixing block 61 and a bolt 62 are provided on the first balance connecting rod 6. The bolt 62 is threadedly assembled with the first fixing block 61, and one end of the bolt 62 is fixedly connected to the first slider 842. By tightening or loosening the bolt 62, the position adjustment of the second guiding mechanism 84 on the first balance connecting rod 6 can be achieved.

[0107] In some embodiments, referring to Figure 7 As shown, let the spring constant of the second balance spring 91 be K2, the elongation be Δx2, the second spring tension generated by the second balance spring 91 under the traction of the second balance rope 92 be F2, and the length of the force arm of the second spring tension F2 with respect to the second joint 5 be h2. The positions of the third guiding mechanism 93 and the fourth guiding mechanism 94 are G and H respectively.

[0108] The second balance moment T generated by the second spring tension F2 on the second joint 5 d is as follows:

[0109] T d = F2 × h2 (15)

[0110] wherein, F2 = K2 × Δx2.

[0111] According to the equality of the areas S of the triangle formed by points A, G, and H ΔAGH it can be obtained that:

[0112]

[0113] wherein, L AG is the distance between the second joint 5 and the third guiding mechanism 93; L AH is the distance between the second joint 5 and the fourth guiding mechanism 94, L GH is the distance between the third guiding mechanism 93 and the fourth guiding mechanism 94; and L GH = Δx2.

[0114] From equation (16), it can be obtained that:

[0115]

[0116] Therefore, the second balancing moment T d is as follows:

[0117]

[0118] It can be seen from Equation (9) and Equation (18) that the second balancing moment T d and the second gravitational moment T b are both related to sinθ1. From T d = T b , the balance between the second balancing moment T d and the second gravitational moment T b can be achieved. Furthermore, it can be obtained that:

[0119]

[0120] According to Equation (19), when the serial manipulator 100 is designed, G1, G2, L AB , G4, are all constants. Therefore, the positions G and H of the third guiding mechanism 93 and the fourth guiding mechanism 94 and the spring constant K2 of the second balancing spring 91 can be reasonably set according to G1, G2, L AB , G4, .

[0121] In some embodiments, after the positions G and H of the third guiding mechanism 93 and the fourth guiding mechanism 94 are determined, a suitable spring can be selected as the second balancing spring 91 according to Equation (19), that is, the spring constant of the second balancing spring 91

[0122] In some embodiments, it can be seen from Equation (18) that when there is a deviation in the magnitudes between the second balancing moment T d and the second gravitational moment T b , the magnitude of the second balancing moment T d can be adjusted by adjusting the positions of the third guiding mechanism 93 and / or the fourth guiding mechanism 94, so that the magnitude of the second balancing moment T d is exactly equal to the magnitude of the second gravitational moment T b , ensuring that the second balancing moment T d can fully balance the second gravitational moment T b .

[0123] Further, the position G of the third guiding mechanism 93 on the first link 2 and / or the position H of the fourth guiding mechanism 94 on the second link 32 can be made adjustable. Regarding how to make the position G of the third guiding mechanism 93 on the first link 2 and / or the position H of the fourth guiding mechanism 94 on the second link 32 adjustable, reference can be made to the relevant description of the adjustable position E of the first guiding mechanism 83 on the first link 2 and / or the position F of the second guiding mechanism 84 on the first balance link 6, which will not be elaborated herein.

[0124] In some embodiments, to ensure that the first spring tension and the second spring tension can respectively generate a first balancing moment and a second balancing moment on the second joint 5, the value range of the angle θ1 of the second link 32 rotating around the second joint 5 can be The value range of the angle θ2 of the first balance link 6 rotating around the second joint 5 can be Wherein, counterclockwise rotation is positive and clockwise rotation is negative. By restricting the rotation of the second link 32 and the first balance link 6 within the corresponding angle ranges, it can be ensured that the moment arms of the first spring tension and the second spring tension relative to the second joint 5 always exist, so that the first spring tension and the second spring tension can always respectively generate a first balancing moment and a second balancing moment on the second joint 5, and at the same time, the directions of the first balancing moment and the second balancing moment always remain unchanged, that is, always opposite to the direction of the gravitational moment at the second joint 5.

[0125] Figure 8 is a schematic structural diagram of a serial manipulator in which the link assembly includes only one link according to some embodiments of the present specification. As Figure 8 shown, in the serial manipulator 200, the link assembly 3 includes only the second link 32, and the second link 32 is rotatably connected to the first link 2 through the second joint 5. The gravity balance assembly can include only one balance mechanism 10, and the balance mechanism 10 can generate a balancing moment on the second joint, and this balancing moment can be used to balance the gravitational moment generated by the second link 32 on the second joint 5, so that the second link 32 is in a completely balanced state, and further the gravity of the serial manipulator is completely balanced.

[0126] In some embodiments, the balance mechanism 10 may include a balance spring 11, a balance rope 12, a first guiding mechanism 13, and a second guiding mechanism 14. Among them, one end of the balance spring 11 is fixedly connected to the first link 2, the other end of the balance spring 11 is fixedly connected to one end of the balance rope 12, the first guiding mechanism 13 is arranged on the first link 2 to guide the other end of the balance rope 12 to the second guiding mechanism 14, and the second guiding mechanism 14 is arranged on the second link 32 to guide the other end of the balance rope 12 to be connected to the second link 32 or the second joint 5. For more descriptions of the first guiding mechanism 13 and the second guiding mechanism 14, reference can be made to the relevant descriptions of the first guiding mechanism 83 and the second guiding mechanism 84.

[0127] In some embodiments, the other end of the balance rope 12 may be directly fixedly connected to the second link 32 or the second joint 5, or may be fixedly tightened to the second link 32 or the second joint 5 through a fixing and tightening mechanism to achieve the connection. For more descriptions of the fixing and tightening mechanism, reference can be made to the relevant descriptions of the first fixing and tightening mechanism 85.

[0128] With the above settings, the balance spring 11 can be in an extended state under the traction of the balance rope 12 to generate a spring tension, and the spring tension can generate a balancing moment on the second joint 5. Specifically, the part of the balance rope 12 located between the first guiding mechanism 13 and the second guiding mechanism 14 is subjected to a spring tension that can generate a balancing moment on the second joint 5. Among them, the elongation of the balance spring 81 is the same as the distance between the first guiding mechanism 13 and the second guiding mechanism 14 (i.e., the length of the balance rope 82 between the first guiding mechanism 13 and the second guiding mechanism 14).

[0129] The balance principle will be described in detail below with reference to the force diagram of the serial manipulator 200.

[0130] Figure 9 is Figure 8 the force diagram when the second link shown rotates a certain angle around the second joint.

[0131] Let the angle of rotation of the second link 32 around the second joint 5 be θ1; the gravity of the second link 32 be G1; the centroid of the second link 32 be O1; the gravitational moments generated by the gravity of the second link 32, the third link 33, the first balance link 6, and the second balance link 7 on the second joint 5 be T1, T2, T3, and T4 respectively; A, B, and C are the positions of the second joint 5, the first guiding mechanism 13, and the second guiding mechanism respectively.

[0132] As Figure 9As shown, the gravitational moment that the serial manipulator 200 needs to balance is the gravitational moment generated by the gravity of the second link 32 on the second joint 5, that is, it has the same expression form as formula (2). Therefore, the gravitational moment T1 that the serial manipulator 200 needs to balance is:

[0133]

[0134] Since Figure 8 the serial manipulator 200 shown can be equivalent to Figure 2 the serial manipulator 100 in which the third link 33, the first balance link 6, and the second balance link 7 are missing. Therefore, the balance mechanism 10 can be equivalent to the second balance mechanism 9 of the serial manipulator 100, that is, the balance moment generated by the balance mechanism 10 on the second joint 5 has the same expression form as formula (18). Therefore, the balance moment T2 generated by the balance mechanism 10 on the second joint 5 is:

[0135] T2 = K × L AB × L AC × sinθ1 (21)

[0136] From the fact that the balance moment T2 generated by the balance mechanism 10 on the second joint 5 is equal in magnitude to the gravitational moment T1 that the serial manipulator 200 needs to balance, it can be obtained that the elastic constant of the balance spring 11, that is, when the manipulator body of the serial manipulator 200 has been designed and the positions of the first guiding mechanism 13 and the second guiding mechanism 14 are determined, the balance spring 11 can be selected according to the elastic constant

[0137] Since the balance mechanism 10 can be equivalent to the second balance mechanism 9, more descriptions about the balance mechanism 10 can refer to the relevant descriptions of the second balance mechanism 9, which will not be elaborated here.

[0138] It should be noted that in the serial manipulator 100 or 200, considering that the link assembly 3 may also include an actuator, therefore, when designing the serial manipulator 100 or 200, for example, when selecting the balance spring according to the spring constant, the gravity of the third link 33 in the serial manipulator 100 or the gravity of the second link 32 in the serial manipulator 200 should include not only its own gravity but also the gravity of the actuator.

[0139] ​The beneficial effects that may be brought about by the embodiments of this specification include, but are not limited to: (1) The serial manipulator provided by the embodiments of this specification achieves complete gravity balance by setting a gravity balance component on the manipulator body. The gravity balance component generates a balancing moment through a spring, with a simple structure and a light weight, without adding much inertial force, and hardly affecting the dexterity and operation accuracy of the serial manipulator, which can ensure a good operation experience for the operator; (2) The balance mechanism in the gravity balance component in the embodiments of this specification can generate a first balancing moment and a second balancing moment to balance the first gravity moment and the second gravity moment that need to be balanced in the serial manipulator respectively, achieving the decoupling of the non-linear relationship between the gravity moment that needs to be balanced in the serial manipulator and the rotation angle, so that the serial manipulator can achieve complete gravity balance at any posture within its motion space; (3) By rotatably connecting the second link, the third link, the first balance link, and the second balance link to form a parallelogram structure, the gravity moment that needs to be balanced in the serial manipulator can be concentrated at the second joint, and the setting position of the driving structure of the serial manipulator is more flexible, so that the structure of the serial manipulator can be more compact; (4) The principle of complete gravity balance in the embodiments of this specification can be applied not only to a serial manipulator with three degrees of freedom (i.e., the link assembly includes one link), but also to a serial manipulator with six degrees of freedom (i.e., the link assembly includes two links).

[0140] It should be noted that different embodiments may produce different beneficial effects. In different embodiments, the beneficial effects that may be produced can be a combination of any one or several of the above, or any other beneficial effects that may be obtained.

[0141] The basic concepts have been described above. Obviously, for those skilled in the art, the above detailed disclosure is only an example and does not constitute a limitation to this specification. Although not explicitly stated here, those skilled in the art may make various modifications, improvements, and corrections to this specification. Such modifications, improvements, and corrections are proposed in this specification, so such modifications, improvements, and corrections still belong to the spirit and scope of the exemplary embodiments of this specification.

[0142] At the same time, this specification uses specific terms to describe the embodiments of this specification. Such as "one embodiment", "an embodiment", and / or "some embodiments" mean a certain feature, structure, or characteristic related to at least one embodiment of this specification. Therefore, it should be emphasized and noted that the "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more at different positions in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this specification can be appropriately combined.

[0143] In addition, unless otherwise specified in the claims, the order of process elements and sequences, the use of numerical and literal characters, or the use of other names in this specification are not used to limit the order of the processes and methods in this specification. Although various examples are discussed in the above disclosure for some currently useful embodiments of the invention, it should be understood that such details are for illustrative purposes only. The appended claims are not limited to the disclosed embodiments. On the contrary, the claims are intended to cover all modifications and equivalent combinations that conform to the essence and scope of the embodiments of this specification. For example, although the system components described above can be implemented by hardware devices, they can also be implemented only by software solutions, such as installing the described system on existing servers or mobile devices.

[0144] Similarly, it should be noted that, in order to simplify the presentation of the disclosure in this specification and thus help the understanding of one or more embodiments of the invention, in the foregoing description of the embodiments of this specification, sometimes multiple features are combined into one embodiment, drawing, or description thereof. However, this method of disclosure does not mean that the features required by the subject matter of this specification are more than those mentioned in the claims. In fact, the features of the embodiments are fewer than all the features of the individual embodiments disclosed above.

[0145] In some embodiments, numbers are used to describe the components and the quantity of attributes. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximate", or "substantially" in some examples. Unless otherwise specified, "about", "approximate", or "substantially" indicate that the stated number allows a variation of ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may vary according to the characteristics required by individual embodiments. In some embodiments, the numerical parameters should consider the specified significant digits and adopt the method of retaining the general number of digits. Although the numerical ranges and parameters used in some embodiments of this specification to confirm the breadth of their scope are approximate values, in specific embodiments, such numerical settings are made as precise as possible within the feasible range.

[0146] For each patent, patent application, patent application publication, and other materials cited in this specification, such as articles, books, specifications, publications, documents, etc., their entire contents are hereby incorporated into this specification by reference. This excludes the application history documents that are inconsistent with or conflict with the content of this specification, as well as the documents that limit the broadest scope of the claims of this specification (currently or subsequently appended to this specification). It should be noted that if there are inconsistencies or conflicts between the descriptions, definitions, and / or the use of terms in the supplementary materials of this specification and the content described in this specification, the descriptions, definitions, and / or the use of terms in this specification shall prevail.

[0147] Finally, it should be understood that the embodiments described in this specification are only used to illustrate the principles of the embodiments of this specification. Other variations may also fall within the scope of this specification. Therefore, by way of example and not limitation, alternative configurations of the embodiments of this specification may be regarded as consistent with the teachings of this specification. Accordingly, the embodiments of this specification are not limited to the embodiments explicitly presented and described in this specification.

Claims

1. A serial manipulator, characterized in that, Comprising: A robotic arm body and a gravity balance assembly; The robotic arm body includes a base, a first link, and a link assembly; The base, the first link, and the link assembly are sequentially rotatably connected through a first joint and a second joint; the link assembly includes a second link, and the second link is rotatably connected to the first link through the second joint; The gravity balance assembly includes at least one balance mechanism, and the at least one balance mechanism can generate at least one balance moment on the second joint; the at least one balance moment is at least used to balance the gravity moment generated by the gravity of the link assembly on the second joint, so that the link assembly is in a completely balanced state; The balance mechanism includes a balance spring, a balance rope, a first guiding mechanism, and a second guiding mechanism; one end of the balance spring is fixedly connected to the first link, the other end of the balance spring is fixedly connected to one end of the balance rope, the first guiding mechanism is arranged on the first link for guiding the other end of the balance rope to the second guiding mechanism, and the second guiding mechanism is arranged on the second link for guiding the other end of the balance rope to be connected to the second link; the balance spring is in an extended state under the traction of the balance rope and generates a spring tension, and the spring tension can generate the balance moment on the second joint; wherein, the elongation of the balance spring is the same as the distance between the first guiding mechanism and the second guiding mechanism; The balance mechanism further includes a fixed tightening mechanism, and the fixed tightening mechanism is used to fixedly tighten the other end of the balance rope on the second link.

2. The serial robotic arm according to claim 1, characterized in that, The link assembly includes a second link and a third link rotatably connected through a third joint; the gravity balance assembly further includes a first balance link and a second balance link; the first balance link, the second balance link, the second link, and a part of the third link are rotatably connected to form a parallelogram structure; wherein, One end of the second link is rotatably connected to one end of the first link and the first balance link through the second joint, and the other end is rotatably connected to the third link through the third joint; one end of the first balance link is rotatably connected to the second link through the second joint, the other end of the first balance link is rotatably connected to one end of the second balance link, and the other end of the second balance link is rotatably connected to the third link; Through the parallelogram structure, the angle of rotation of the third link around the third joint can be jointly determined by the angle of rotation of the second link around the second joint and the angle of rotation of the first balance link around the second joint.

3. The serial robotic arm according to claim 2, characterized in that, The gravity balance assembly includes a first balance mechanism and a second balance mechanism; The first balance mechanism and the second balance mechanism can respectively generate a first balance moment and a second balance moment on the second joint, and the first balance moment and the second balance moment are used to balance the gravity moment generated by the gravity of the second link, the third link, the first balance link, and the second balance link on the second joint; wherein The first balancing moment is at least related to the angle of rotation of the first balance link about the second joint, and the second balancing moment is at least related to the angle of rotation of the second link about the second joint.

4. The serial manipulator according to claim 3, wherein The second joint includes a first rotating half shaft and a second rotating half shaft arranged opposite to each other; one end of the second link is fixedly connected to the first rotating half shaft; one end of the first balance link is fixedly connected to the second rotating half shaft.

5. The serial manipulator according to any one of claims 2 to 4, characterized in that The first balance mechanism includes a first balance spring, a first balance rope, a first guiding mechanism, and a second guiding mechanism; One end of the first balance spring is fixedly connected to the first link, and the other end of the first balance spring is fixedly connected to one end of the first balance rope; the first guiding mechanism is arranged on the first link to guide the other end of the first balance rope to the second guiding mechanism, and the second guiding mechanism is arranged on the first balance link to guide the other end of the first balance rope to be connected to the first rotating half shaft; The first balance spring is in an extended state under the traction of the first balance rope and generates a first spring tension, and the first spring tension can generate a first balancing moment on the second joint; wherein, The elongation of the first balance spring is the same as the distance between the first guiding mechanism and the second guiding mechanism.

6. The serial robotic arm according to claim 5, wherein The first balance mechanism further includes a first balance rope fixing and tightening mechanism for fixing and tightening the other end of the first balance rope on the first rotating half shaft.

7. The serial robotic arm according to claim 5, characterized in that, The position of the first guiding mechanism on the first link and / or the position of the second guiding mechanism on the first balance link are adjustable.

8. The serial manipulator according to any one of claims 2 to 4, characterized in that, The second balance mechanism includes a second balance spring, a second balance rope, a third guiding mechanism, and a fourth guiding mechanism; one end of the second balance spring is fixedly connected to the second link, the other end of the second balance spring is fixedly connected to one end of the second balance rope, the third guiding mechanism is arranged on the first link for guiding the other end of the second balance rope to the fourth guiding mechanism, and the fourth guiding mechanism is arranged on the second link for guiding the other end of the second balance rope to be connected to the second link or the second rotating half shaft, The second balance spring is in an extended state under the traction of the second balance rope and generates a second spring tension, and the second spring tension can generate a second balancing moment on the second joint; wherein, The elongation of the second balance spring is the same as the distance between the third guiding mechanism and the fourth guiding mechanism.

9. The serial manipulator according to claim 8, wherein, The second balance mechanism further includes a second balance rope fixing and tightening mechanism for fixing and tightening the other end of the second balance rope on the second link or the second rotating half shaft.

10. The serial robotic arm according to claim 8, wherein The position of the third guiding mechanism on the first link and / or the position of the fourth guiding mechanism on the second link are adjustable.

11. The serial manipulator according to claim 5, wherein The spring constant of the first balance spring ; wherein, K k1 is the spring constant of the first balance spring, G G3 is the gravity of the third link, r3 is the distance between the third joint and the centroid of the third link, G G1 is the gravity of the first balance link, r1 is the distance between the second joint and the centroid of the first balance link, G G2 is the gravity of the second balance link, l1 is the length of the first balance link, s1 is the distance between the first guiding mechanism and the second joint, s2 is the distance between the second guiding mechanism and the second joint.

12. The serial manipulator according to claim 8, wherein The spring constant of the second balance spring ; wherein, K $k_2$ is the spring constant of the second balance spring, G $G_1$ is the gravity of the second link, $l_{c1}$ is the distance between the second joint and the centroid of the second link, G $G_2$ is the gravity of the third link, $l_2$ is the length of the second link, G $G_4$ is the gravity of the second balance link, $l_{c4}$ is the distance between the connection point between the first balance link and the second balance link and the centroid of the second balance link, $l_3$ is the distance between the third guiding mechanism and the second joint, $l_4$ is the distance between the fourth guiding mechanism and the second joint.

13. The serial robotic arm according to claim 1, wherein The gravity balance component includes a balance mechanism, and the balance mechanism is capable of generating a balance moment on the second joint, and the balance moment is used to balance the gravity moment generated by the gravity of the second link on the second joint.

14. The serial robotic arm according to claim 13, wherein The spring constant of the balance spring ; wherein, K is the spring constant of the balance spring, G 1 is the gravity of the second link, is the distance between the second joint and the center of gravity of the second link, is the distance between the first guiding mechanism and the second joint, is the distance between the second guiding mechanism and the second joint.

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