CN216803503U - Mechanical arm of establishing ties - Google Patents

Abstract

Embodiments of the present description provide a serial robot arm, which includes a robot arm body and a gravity balance assembly; the mechanical arm body comprises a base, a first connecting rod and a connecting rod assembly; the base, the first connecting rod and the connecting rod assembly are sequentially connected in a rotating mode through a first joint and a second joint; the gravity balance assembly comprises at least one balancing mechanism capable of generating at least one balancing moment to the second joint; the at least one balancing moment is at least used for balancing a gravity moment generated by the gravity of the connecting rod assembly on the second joint so as to enable the connecting rod assembly to be in complete balance. The series mechanical arm provided by the embodiment of the specification can realize complete gravity balance in any posture in the motion space, has a simple and compact structure, and has better flexibility, operation precision and operation comfort.

Description

Mechanical arm of establishing ties

Technical Field

The specification relates to the field of mechanical arms, in particular to a serial mechanical arm.

Background

The mechanical arm is widely applied to the fields of industry, medical treatment and the like as a novel man-machine interaction way. The serial mechanical arm is a common mechanical arm, and an operator can carry out industrial production, surgical treatment and the like by operating the serial mechanical arm. For example, the tandem robot arm may be used as a doctor robot arm as an important component of a surgical robot, and a doctor may control the distal end of the surgical robot to perform actions such as cutting, knotting, and suturing by operating the doctor robot arm.

However, when an operator operates the tandem robot arm, the gravity of the tandem robot arm itself adversely affects the dexterity and the operation accuracy of the tandem robot arm and the force feedback of the operator, and also causes the muscle of the operator to feel tired even when the operator operates for a long time. Therefore, the design of the robot arm usually needs to consider the problem of complete gravity balance to eliminate the negative effect of the gravity of the tandem robot arm.

SUMMERY OF THE UTILITY MODEL

An embodiment of the present specification provides a serial robot arm, including: the mechanical arm comprises a mechanical arm body and a gravity balance assembly; the mechanical arm body comprises a base, a first connecting rod and a connecting rod assembly; the base, the first connecting rod and the connecting rod assembly are sequentially connected in a rotating mode through a first joint and a second joint; the gravity balance assembly comprises at least one balancing mechanism capable of generating at least one balancing moment to the second joint; the at least one balancing moment is at least used for balancing a gravity moment generated by the gravity of the connecting rod assembly on the second joint so as to enable the connecting rod assembly to be in complete balance.

In some embodiments, the linkage assembly includes a second link and a third link rotationally connected by a third joint; the gravity balance assembly further comprises a first balance connecting rod and a second balance connecting rod; portions of the first, second, and third balance links are rotationally connected to form a parallelogram structure; one end of the second connecting rod is rotatably connected with one ends of the first connecting rod and the first balance connecting rod through the second joint, and the other end of the second connecting rod is rotatably connected with the third connecting rod through the third joint; one end of the first balance connecting rod is rotatably connected with the second connecting rod through the second joint, the other end of the first balance connecting rod is rotatably connected with one end of the second balance connecting rod, and the other end of the second balance connecting rod is rotatably connected to the third connecting rod; the angle by which the third link can be rotated about the third joint by the parallelogram structure is determined by the angle by which the second link is rotated about the second joint and the angle by which the first balance link is rotated about the second joint.

In some embodiments, the gravity balancing assembly comprises a first balancing mechanism and a second balancing 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 for balancing the gravity moment generated by the gravity of the second connecting rod, the third connecting rod, the first balance connecting rod and the second balance connecting rod on the second joint; wherein the first balancing moment is related to at least an angle of rotation of the first balancing link about the second joint and the second balancing moment is related to at least an angle of rotation of the second link about the second joint.

In some embodiments, the second joint comprises a first rotary half shaft and a second rotary half shaft disposed opposite each other; one end of the second connecting rod is fixedly connected with the first rotating half shaft; one end of the first balance connecting rod is fixedly connected with the second rotary half shaft.

In some embodiments, the first counterbalance mechanism comprises a first counterbalance spring, a first counterbalance rope, a first guide mechanism, a second guide 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 with one end of the first balance rope; the first guide mechanism is provided on the first link to guide the other end of the first balance rope to the second guide mechanism, and the second guide mechanism is provided on the first balance link to guide the other end of the first balance rope to be connected to the first rotary half shaft; the first balance spring is in an extension 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 an elongation amount of the first balance spring is the same as a distance between the first guide mechanism and the second guide mechanism.

In some embodiments, the first balance mechanism further comprises a first balance rope fixed tightening mechanism for fixedly tightening the other end of the first balance rope on the first rotary axle shaft.

In some embodiments, the position of the first guide mechanism on the first link and/or the position of the second guide mechanism on the first balancing link is adjustable.

In some embodiments, the second counterbalance mechanism includes a second counterbalance spring, a second counterbalance rope, a third guide mechanism, a fourth guide mechanism; one end of the second balance spring is fixedly connected to the first connecting rod, the other end of the second balance spring is fixedly connected to one end of the second balance rope, the third guide mechanism is arranged on the first connecting rod and used for guiding the other end of the second balance rope to a fourth guide mechanism, the fourth guide mechanism is arranged on the second connecting rod and used for guiding 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 extension state under the traction of the second balance rope and generates a second spring tension, and the second spring tension can generate a second balance moment on the second joint; wherein an elongation of the second balancing spring is the same as a distance between the third guide mechanism and the fourth guide mechanism.

In some embodiments, the second balance mechanism further comprises a second balance rope fixed tightening mechanism, and the second balance rope fixed tightening mechanism is used for fixedly tightening the other end of the second balance rope on the second connecting rod or the second rotary half shaft.

In some embodiments, the position of the third guide mechanism on the first link and/or the position of the fourth guide mechanism on the second link is adjustable.

In some embodiments, the first balancing spring has a spring constant

Wherein, K₁Is the spring constant of the first balance spring, G₂Is the weight force of the third link and,

is the distance, G, between the third joint and the center of mass of the third link₃In order to balance the weight force of the link,

is the distance, G, between the second joint and the center of mass of the first balance link₄Is the weight of the second balance link, L_ACIs the length, L, of the first balancing link_AEIs the distance, L, between the first guide mechanism and the second joint_AFIs the distance between the second guide mechanism and the second joint.

In some embodiments, the second balancing spring has a spring constant

Wherein, K₂Is the spring constant of the second balance spring, G₁Is the gravity of the second connecting rod,

is the distance, G, between the second joint and the center of mass of the second link₂Is the gravity of the third link, L_ABLength of said second link, G₄In order for the second balancing link to be gravitational,

is the distance between the connecting point between the first and second balance connecting rods and the center of mass of the second balance connecting rod, L_AGIs the distance, L, between the third guide mechanism and the second joint_AHIs the distance between the fourth guide mechanism and the second joint.

In some embodiments, the linkage assembly includes a second link rotationally coupled to the first link by the second joint; the gravity balance assembly comprises a balance mechanism, the balance mechanism can generate a balance moment on the second joint, and the balance moment is used for balancing the gravity moment generated by the gravity of the second connecting rod on the second joint.

In some embodiments, the counterbalance mechanism includes a counterbalance spring, a counterbalance cord, a first guide mechanism, a second guide mechanism; one end of the balance spring is fixedly connected to the first connecting rod, the other end of the balance spring is fixedly connected with one end of the balance rope, the first guide mechanism is arranged on the first connecting rod and used for guiding the other end of the balance rope to the second guide mechanism, and the second guide mechanism is arranged on the second connecting rod and used for guiding and connecting the other end of the balance rope to the second connecting rod; the balance spring is in an extension state under the traction of the balance rope and generates spring tension, and the spring tension can generate the balance moment on the second joint; wherein an elongation amount of the balance spring is the same as a distance between the first guide mechanism and the second guide mechanism.

In some embodiments, the spring constant of the balancing spring

Wherein K is the spring constant of the balance spring, G₁Is a stand forThe gravity of the second connecting rod is used,

is the distance between the second joint and the center of gravity of the second link, L_ABIs the distance, L, between the first guide mechanism and the second joint_ACIs the distance between the second guide mechanism and the second joint.

Drawings

The present description will be further explained by way of exemplary embodiments, which will be described in detail by way of the accompanying drawings. These embodiments are not intended to be limiting, and in these embodiments like numerals are used to indicate like structures, wherein:

FIG. 1 is a front view of a tandem robot arm having a linkage assembly including two links, according to some embodiments of the present disclosure;

FIG. 2 is a rear view of a tandem robot arm having a linkage assembly including two links in accordance with certain embodiments of the present disclosure;

FIG. 3 is a cross-sectional view taken along A-A of FIG. 1;

FIG. 4 is an enlarged fragmentary view of the area of FIG. 1 in which the first counterbalancing moment is generated;

FIG. 5 is an enlarged fragmentary view of the area of FIG. 2 in which the second equilibrium moment is generated;

FIG. 6 is a force diagram of the second link and the first balance link shown in FIG. 1 when they are rotated at an angle about the second joint;

FIG. 7 is a force diagram of the second link and the first balancing link shown in FIG. 2 rotated at an angle about the second joint;

FIG. 8 is a schematic diagram of a tandem robot arm having a linkage assembly including only one linkage according to some embodiments of the present disclosure;

fig. 9 is a force-bearing schematic diagram of the second link shown in fig. 8 when the second link rotates around the second joint by a certain angle.

Reference numerals: 100 is a tandem robot arm; 2 is a base; 3 is a connecting rod component; 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 rotary half shaft; second rotary axle shaft 52; 6 is a first balance connecting rod; 61 is a first fixed block; 62 is a bolt; 7 is a second balance connecting rod; 8 is a first balance mechanism; 81 is a first balance spring; 82 is a first balance rope; 83 is a first guide mechanism; 831 is a first guide wheel; 832 is a first bracket; 84 is a second guide mechanism; 85 is a first fixed tightening mechanism; 851 is a first tightening wheel; 852 is a first tightening block; 9 is a second balance mechanism; 91 is a second balance spring; 92 is a second balance rope; 93 is a third guide mechanism; a fourth guide mechanism 94; 95 is a second fixed tightening mechanism; 200 is a tandem arm; 10 is a balance mechanism; 11 is a balance spring; 12 is a balance rope; 13 is a first guide mechanism; and 14, a second guide mechanism.

Detailed Description

In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings used in the description of the embodiments will be briefly described below. It is obvious that the drawings in the following description are only examples or embodiments of the present description, and that for a person skilled in the art, the present description can also be applied to other similar scenarios on the basis of these drawings without inventive effort. Unless otherwise apparent from the context, or stated otherwise, like reference numbers in the figures refer to the same structure or operation.

It should be understood that "system", "apparatus", "unit" and/or "module" as used herein is a method for distinguishing different components, elements, parts, portions or assemblies at different levels. However, other words may be substituted by other expressions if they accomplish the same purpose.

As used in this specification and the appended claims, the terms "a," "an," "the," and/or "the" are not intended to be inclusive in the singular, but rather are intended to be inclusive in the plural, unless the context clearly dictates otherwise. In general, the terms "comprises" and "comprising" are intended to cover only the explicitly identified steps or elements as not constituting an exclusive list and that the method or apparatus may comprise further steps or elements.

The mechanical arm is an important component in robot systems such as industrial robots and surgical robots, and can generally comprise three types, namely a series mechanical arm, a parallel mechanical arm and a series-parallel mechanical arm. In practice, most of the common robots are in-line robots. For example, in the surgical treatment, the doctor can control the end effector of the surgical robot to perform actions such as cutting, knotting, and suturing by operating the doctor's robot arm. Among them, the doctor's robot is mostly a tandem robot.

However, if the tandem robot arm has a problem that the gravity cannot be balanced completely, and thus when an operator operates the tandem robot arm, the gravity of the tandem robot arm itself and the inertial force generated during the movement thereof may cause fatigue to the operator, and may also cause a reduction in the operation accuracy and dexterity of the tandem robot arm and an inaccurate force feedback to the operator. The gravity complete balance of the serial mechanical arm can be understood as that the serial mechanical arm can be in any posture in the motion space of the serial mechanical arm, for example, when a motion member (for example, a connecting rod) in the serial mechanical arm rotates to a certain position and the received driving force disappears, the gravity of the motion member can be balanced, so that the motion member can not rotate again due to the self gravity, the motion member can be kept at the current position, and the serial mechanical arm can keep the corresponding posture after the driving force for driving the motion of the serial mechanical arm disappears. Specifically, the gravity complete balance can be realized by balancing the gravity moment generated by the gravity of the connecting rod in the series mechanical arm to the joint, and the gravity moment generated by the gravity of the connecting rod in the series mechanical arm to the joint can be realized by offsetting the gravity moment by the moment which is generated by the same joint and has the same size and the opposite direction to the gravity moment.

In some embodiments, the gravity complete balance of the serial mechanical arm may be achieved by means of a counterweight design, for example, a suitable counterweight may be added to a symmetric direction of a connecting rod of the serial mechanical arm with respect to a joint, and a moment generated by the gravity of the counterweight on the joint may be used to balance the moment generated by the gravity of the connecting rod on the joint, so as to achieve the gravity complete balance of the serial mechanical arm. However, the overall mass and inertia force of the tandem mechanical arm can be increased by adding the counterweight, and the space size and the structural complexity of the tandem mechanical arm can also be increased to a certain extent, so that the dexterity, the operation comfort and the operation precision of the tandem mechanical arm can be reduced to different degrees.

In some embodiments, the gravity of the tandem robot arm can be completely balanced by means of motor compensation, for example, the gravity of each link of the tandem robot arm can be completely balanced by balancing the gravity moment of the corresponding joint by the gravity of each link of the tandem robot arm through the output of the motor with a reverse torque. However, the motor compensation method consumes a large amount of torque of the motor, which results in an excessive selection of the motor and may cause inaccurate force feedback to the operator by the serial robot.

Embodiments of the present disclosure provide a serial robot arm, which uses a balance moment generated by a spring pulling force generated by a spring in an extended state to a joint in the serial robot arm to balance a gravity moment required to be balanced in the serial robot arm (i.e., a gravity moment generated by a gravity of a moving member in the serial robot arm to the joint), so as to achieve complete gravity balance of the serial robot arm. When the gravity distance required to be balanced changes along with the change of the rotation angle of the related moving component (for example, a connecting rod) of the serial mechanical arm, the balance moment also changes along with the change of the rotation angle of the related moving component of the serial mechanical arm, so that the serial mechanical arm can realize complete gravity balance when the related moving component rotates at any angle. In addition, the tandem robot arm provided by the embodiment of the specification realizes complete gravity balance by enabling the spring to be in an extension state, has a simple and compact structure and a light weight, does not increase excessive inertia force to influence the operation precision and the operation comfort of the tandem robot arm, and does not interfere the motion of the tandem robot arm.

A tandem robot arm provided by embodiments of the present description may include a robot arm body and a gravity balance assembly. Wherein, the arm body includes base, first connecting rod and link assembly, and base, first connecting rod and link assembly rotate through first joint, second joint and connect, and first connecting rod can carry out the axial for the base around first joint promptly, and link assembly can rotate around the second joint for first connecting rod. The gravity balancing assembly may include at least one balancing mechanism configured to generate at least one balancing moment on the second joint, the at least one balancing moment may be used to at least balance a gravitational moment of the connecting rod assembly generated by gravity on the second joint to fully balance the connecting rod assembly. Wherein, the balance mechanism comprises a spring, and the spring can be in an extension state to generate spring tension, so as to generate balance moment for the second joint. In addition, the balance mechanism can also enable the elongation of the spring to change along with the change of the rotation angle of the connecting rod assembly, so that the balance moment can also change along with the change of the rotation angle of the connecting rod assembly like the gravity distance, and the connecting rod assembly can be in complete balance when rotating at any angle.

In some embodiments, when the link assembly is in full balance, it may be understood that the link assembly may be kept in balance in any posture of the motion space (for example, when the link assembly rotates by any angle) when the serial mechanical arm is not subjected to an external force, that is, when the link assembly rotates to a certain position, the link assembly may not rotate due to its own gravity when the external force (for example, a driving force applied to the link assembly during the rotation process) disappears, so that the link assembly may be kept at the current position.

It should be noted that, because the first link rotates around the first joint relative to the base, and the gravity of the first link acts on the base, the gravity of the first link does not need to be balanced (i.e., the gravity of the first link does not generate a gravitational moment on the second joint), and when the gravity of the link assembly is balanced and is in full balance, the gravity of the serial mechanical arm can be fully balanced.

In some embodiments, in order to meet the design requirements of different degrees of freedom of the tandem robot arm, the connecting rod assembly may include one connecting rod or two connecting rods rotationally connected through a third joint. For another example, when the link assembly includes two links, the tandem robot arm has six degrees of freedom, and is widely used in robot systems such as industrial robots and surgical robots.

In some embodiments, for the case where the linkage assembly includes one link or includes two links rotationally connected by the third joint, the number of balancing mechanisms in the gravity balancing assembly may be one or two, respectively. In some embodiments, when the gravity balance assembly includes a balancing mechanism, a balancing moment can be generated to balance the gravitational moment of the connecting rod assembly (including only the first connecting rod) on the second joint. When the gravity balance assembly includes two balance mechanisms, considering that the gravity of the connecting rod assembly also generates a gravity moment to the third joint in the connecting rod assembly, the gravity balance assembly further includes a balance link to transfer the gravity moment at the third joint to the second joint, and thus, the two balance mechanisms in the gravity balance assembly can generate two balance moments to balance the gravity of the connecting rod assembly (including the two links) and the gravity moment generated by the balance link (e.g., a balance link described below) in the gravity balance assembly to the second joint.

In some embodiments, the linkage assembly may include, in addition to a link, an actuator rotatably coupled to a distal end of the link (e.g., a welding torch in a welding robot, a surgical instrument of a surgical robot, etc.). Thus, the link assembly being in full balance may include the links in the link assembly and the moment of gravity of the actuator on the second joint being balanced (or referred to as offset) by the corresponding balancing moments.

The embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings, wherein the link assembly includes two links and the tandem robot arm includes only one link, and the balancing principle thereof is described in detail.

FIG. 1 is a front view of a tandem robot arm having a linkage assembly including two links according to some embodiments of the present disclosure. FIG. 2 is a rear view of a tandem robot arm having a linkage assembly including two links according to some embodiments of the present disclosure. Fig. 3 is a sectional view taken along a-a of fig. 1.

In some embodiments, as shown in conjunction with figures 1, 2, and 3, the tandem robot arm 100 includes a robot arm body and a gravity balance assembly. The mechanical arm body comprises a base 1, a first connecting rod 2 and a connecting rod assembly 3. The first link 2 is rotatably connected to the base 1 by a first joint 4, so that the first link 2 can rotate relative to the base 1 about a rotation axis direction of the first joint 4 (for example, a Z-axis direction shown in fig. 1 or a direction parallel to the Z-axis). The link assembly 3 is rotatably connected to the first link 2 via a second joint 5, so that the link assembly 3 can rotate relative to the first link 2 about a rotation axis direction of the second joint 5 (for example, an X-axis direction shown in fig. 1 or a direction parallel to the X-axis). The link assembly 3 may include a second link 32 and a third link 33 rotatably connected by a third joint 31, and the third link 32 may rotate relative to the second link 32 around a rotation axis direction of the third joint 31 (e.g., an X-axis direction or a direction parallel to the X-axis direction shown in fig. 1). The rotation axes of the second joint 5 and the third joint 6 are both in a direction perpendicular to the paper surface in fig. 1, i.e., in the X-axis direction shown in fig. 1 or in a direction parallel to the X-axis.

With continued reference to fig. 1, 2, and 3, the gravity balance assembly may include a first balance link 6 and a second balance link 7. Wherein, part or all of the first balance link 6, the second balance link 7, the second link 32 and the third link 33 can be rotatably connected to form a parallelogram structure.

Specifically, one end of the second link 32 is rotatably connected to one ends 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 a third link 33 via a 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. Wherein the second link 32 and the first balance link 6 rotate independently around the second joint 5.

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 (the 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 connection among part 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.

The parallelogram structure formed by the rotation connection among part or all of the first balance link 6, the second balance link 7, the second link 32 and the third link 33 can make the angle of rotation of the third link 33 around the third joint 31 be determined by the angle of rotation of the second link 32 around the second joint 5 and the angle of rotation of the first balance link 6 around the second joint 5, that is, in the case that the angle of rotation of the second link 32 around the second joint 5 and the angle of rotation of the first balance link 6 around the second joint 5 are determined, the angle of rotation of the third link 33 around the third joint 31 can also be determined, and then when the gravity moments at the second joint 5 (i.e. the gravity moments 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) are balanced (or cancelled), the gravity moment at the third joint 31 (i.e. the gravity moments 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) are balanced (or cancelled out), The moment of gravity generated by the second balance link 7, the second link 32, and the third link 33 with respect to 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 by the parallelogram structure. Therefore, to achieve the gravity balance of the serial robot arm 100, the gravity moment at the second joint 5 needs to be balanced.

Besides, by the parallelogram structure, it is not necessary to provide a driving mechanism (e.g., a motor) at the third joint 31 to drive the rotation of the third link 33, but only a driving mechanism at the second joint 5 is required to drive the rotation of the second link 32 and the first balance link 6, and by the parallelogram structure, 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, so that the structure of the serial robot arm 100 can be made more compact, and the problem of complicated wiring of the driving mechanism of the serial robot arm 100 can be solved to some extent.

In some embodiments, the first balance link 6 may also be driven to rotate around the second joint 5 by rotating the second link 32 and the third link 33 through a parallelogram structure, that is, a driving mechanism for driving the third link 33 to rotate is disposed at the third joint 31, and a driving mechanism for driving only the second link 32 to rotate is disposed at the second joint 5, where an angle of rotation of the first balance link 6 around the second joint 5 may be determined by an angle of rotation of the third link 33 around the third joint 31 and an angle of rotation of the second link 32 around the second joint 5.

In some embodiments, the second link 32 may also be driven to rotate around the second joint 5 by rotating the third link 33 and the first balance link 6 through a parallelogram structure, that is, a driving mechanism for driving the third link 33 to rotate is disposed at the third joint 31, and a driving mechanism for driving only the first balance link 6 to rotate is disposed at the second joint 5, where an angle of rotation of the second link 32 around the second joint 5 may be determined by an angle of rotation of the third link 33 around the third joint 31 and an angle of rotation of the first balance link 6 around the second joint 5.

To balance the gravitational moment at the second joint 5 to achieve full balance of the tandem robot arm 100, the gravitational balancing assembly may include a first balancing mechanism 8 and a second balancing mechanism 9, as shown in fig. 2. The first balance mechanism 8 and the second balance mechanism 9 can generate a first balance moment and a second balance moment for the second joint 5 respectively, and the first balance moment and the second balance moment can be used for balancing the gravity moment generated by the second connecting rod 32, the third connecting rod 33, the first balance connecting rod 6 and the second balance connecting rod 7 for the second joint 5 together, so that the gravity complete balance of the serial mechanical arm 100 is realized. Specifically, the vector sum of the first balance moment and the second balance moment is equal to and opposite to the vector sum of the gravity moments 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, so as to balance (or cancel) the gravity moment at the second joint 5.

Since the vector sum of the first balance moment and the second balance moment and the gravity moment generated by the second connecting rod 32, the third connecting rod 33, the first balance connecting rod 6 and the second balance connecting rod 7 to the second joint 5 can be changed along with the change of the rotating angle of the second connecting rod 32 and the first balance connecting rod 6 around the second joint, in order to ensure that the serial mechanical arm 100 can realize gravity complete balance under any posture in the motion space thereof, namely when the second connecting rod 32 and the first balance connecting rod 6 rotate around the second joint 5 by any angle, the second connecting rod 32, the third connecting rod 33, the first balance connecting rod 6 and the second balance connecting rod 7 are in complete balance, the first balance moment is at least related to the rotating angle of the first balance connecting rod 6 around the second joint 5, and the second balance moment is at least related to the rotating angle of the second connecting rod around the second joint 5, so that the first balance moment and the second balance moment can also be related to the rotating angle of the second connecting rod 32 and the first balance connecting rod 6 around the second joint The change of the first and second balance moments is changed so that the vector sum of the first and second balance moments is always equal to and opposite to the vector sum of the gravity moments generated by the second, third, first, and second balance links 32, 33, 6, and 7 with respect to the second joint 5. Specific relationships between the first balancing moment, the second balancing moment and the moment of gravity at the second joint 5, and specific relationships between the first balancing moment, the second balancing moment and the moment of gravity at the second joint 5 and the angle of rotation of the second link 32 and the first balancing link 6 about the second joint 5, can be found elsewhere in this specification (e.g., fig. 6 and 7 and their associated descriptions).

In some embodiments, in order to make the rotation of the second link 32 and the first balance link 6 about the second joint 5 independent from each other, the second joint 5 may comprise a first rotary half-shaft 51 and a second rotary half-shaft 52 which are oppositely arranged, see fig. 3. Wherein, one end of the second connecting rod 32 is fixedly connected with the first rotating half-shaft 51, and one end of the first balance connecting rod 6 is fixedly connected with the second rotating half-shaft. By arranging the first and second rotary half shafts 51, 52 with a certain clearance in the axial direction thereof or with relative rotation between the first and second rotary half shafts 51, 52, the rotation of the second link 32 about the second joint 5 and the rotation of the first balance link 6 about the second joint 5 can be made independent of each other.

The following will describe in detail how the first and second counterbalancing means generate the first and second counterbalancing moments, respectively.

Referring to fig. 1, the first balancing mechanism 8 may include a first balancing spring 81, a first balancing string 82, a first guide mechanism 83, and a second guide mechanism 84. One end of the first balance spring 81 is fixedly connected to the first link 2 and located on the same side (left side in fig. 3) as the first rotating axle shaft 51, and the other end of the first balance spring 81 is fixedly connected to one end of the first balance rope 82. The first guide mechanism 83 is provided on the first link 2 to guide the other end of the first balance rope 82 to the second guide mechanism 84, and the second guide mechanism 84 is provided on the first balance link 6 to guide the other end of the first balance rope 82 to the first rotary half shaft 51, the other end of the first balance rope 82 being connected to the first rotary half shaft 51.

In some embodiments, the other end of the first balancing cord 82 may be fixedly attached directly to the first rotary axle shaft 51. In some embodiments, referring to fig. 1, the first counterbalance mechanism 8 may further include a first counterbalance cord securing take-up mechanism 85.

Fig. 4 is a partially enlarged view of the area in fig. 1 where the first balancing moment is generated.

As shown in fig. 4, the first balance cord fixing and tightening mechanism 85 may include a first tightening pulley 851 and a first tightening press block 852. Wherein, first take-up pulley 851 can be used for taking up first balance rope 82, and first tightening pressure block 852 can be fixed the other end of first balance rope 82 on first take-up pulley 851, and first tightening pulley 851 and first tightening pressure block 852 are all fixed on first rotating shaft 51 to the realization is tightened up the fixed of the other end of first balance rope 82.

With the above arrangement, 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 portion of the first balancing cord 82 between the first guide mechanism 83 and the second guide mechanism 84 is subjected to the first spring tension to generate the first balancing moment to the second joint 5. Wherein the elongation of the first balancing spring 81 is the same as the distance between the first guide mechanism 82 and the second guide mechanism 83 (or the length of the first balancing cord 82 between the first guide mechanism 82 and the second guide mechanism 83).

Referring to fig. 2, the second balancing mechanism 9 may include a second balancing spring 91, a second balancing string 92, a third guide mechanism 93, and a fourth guide mechanism 94. One end of the second balance spring 91 is fixedly connected to the first link 2 and located on the same side (right side in fig. 3) as the second rotating half shaft 52, and the other end of the second balance spring 91 is fixedly connected to one end of the second balance rope 92. The third guide mechanism 93 is provided on the first link 2 to guide the other end of the second balance cord 92 to the fourth guide mechanism 94, and the fourth guide mechanism 94 is provided on the second link 32 to guide the other end of the second balance cord 92 to be connected to the second link 32. In some embodiments, a fourth guide mechanism 94 may guide the other end of the second balancing cord 92 to the second half-shaft 52.

In some embodiments, the other end of the second balancing cord 92 may be fixedly coupled directly to the second link 32. Fig. 5 is a partially enlarged view of the region in fig. 2 where the second equilibrium moment is generated. In some embodiments, as shown in fig. 2 and 5 in combination, the second balance mechanism 9 may further include a second balance cord securing tightening mechanism 95.

The second balance cord fixing and tightening mechanism 95 may be used to fixedly tighten the other end of the second balance cord 92 on the second link 32. In some embodiments, the second balance cord fixed tightening mechanism 95 may have a similar structure to the first balance cord fixed tightening mechanism 85, and further description of the second balance cord fixed tightening mechanism 95 may be found above with reference to the description of the first balance cord fixed tightening mechanism 85.

With the above arrangement, the second balancing spring 91 can be extended under the traction of the second balancing rope 92 to generate a second spring tension, and the second spring tension can generate a second balancing moment on the second joint 5. Specifically, the portion of the second balancing cord 92 located between the third guide mechanism 93 and the fourth guide mechanism 94 may be subjected to the second spring tension to generate a second balancing moment to the second joint 5. Wherein the elongation amount of the second balancing spring 91 is the same as the distance between the third guide mechanism 93 and the fourth guide mechanism 94 (or the length of the second balancing string 92 between the third guide mechanism 93 and the fourth guide mechanism 94).

In some embodiments, the first guide mechanism 83, the second guide mechanism 84, the third guide mechanism 93 and the fourth guide mechanism 94 may include at least a rotatable guide wheel, and the first balancing rope 82 and the second balancing rope 92 may be wound around the guide wheel of the respective guide mechanism to guide the other end thereof to the corresponding position.

In some embodiments, the spring constant of the first counter-spring 81 and/or the second counter-spring 91 may be selected based on relevant parameters (e.g., gravity, length, etc.) of the second link 32, the third link 33, the first counter-link 6, the second counter-link 7, and one or more of the distance between the first guide mechanism 8, the second guide mechanism 84 and/or the third guide mechanism 93, the second guide mechanism 94, and the second joint 5. Specific relationships regarding the spring constants 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, the second balance link 7 (e.g., gravity, length, etc.) and the distances between the first guide mechanism 83, the second guide mechanism 84 and/or the third guide mechanism 93, the second guide mechanism 94 and the second joint 5 may be found elsewhere in this specification (e.g., fig. 6 and 7 and their associated descriptions).

The balance principle will be described in detail below with reference to the force diagram of the serial robot 100.

Fig. 6 is a force-bearing schematic diagram of the second link and the first balance link shown in fig. 1 when they rotate a certain angle around the second joint. Fig. 7 is a force diagram of the second link and the first balance link shown in fig. 2 when they rotate a certain angle around the second joint.

As shown in fig. 6 or 7, the angle of rotation of the second link 32 about the second joint 5 is θ₁The angle of rotation of the first balance link 6 around the second joint 5 is theta₂(ii) a The gravity of the second link 32, the third link 33, the first balance link 6 and the second balance link 7 is G₁、G₂、G₃、G₄(ii) a Of the second link 32, third link 33, first balance link 6, second balance link 7The centroids are respectively O₁、O₂、O₃、O₄(ii) a The gravity moment generated by the gravity of the second connecting rod 32, the third connecting rod 33, the first balance connecting rod 6 and the second balance connecting rod 7 on the second joint 5 is T₁、T₂、T₃、T₄(ii) a A. B, C, D are the locations 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.

Thus, the gravitational moment T that the tandem robot arm 100 needs to balance is:

T＝T₁+T₂+T₃+T₄ (1)

calculated to obtain, T₁、T₂、T₃、T₄Respectively as follows:

wherein the content of the first and second substances,

is the distance between the second joint 5 and the center of mass of the second link 32; l is_ABIs 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 center of mass of the third link 33;

is the distance between the second joint 5 and the centre of mass of the first balancing link 6;

is the distance between the connection point between the first and second balance links 6, 7 and the centre of mass of the second balance link 7, L_ACIs 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).

The compounds represented by the formula (2), (3), (4) and (5) can be substituted into the formula (1):

combining the same terms of formula (6) can yield:

according to equation (7), the moment of gravity T of the serial robot arm 100 to be balanced can be divided into the first moment of gravity T_aAnd a second gravity distance T_b：

Further, the first balancing moment generated by the first balancing mechanism 8 on the second joint 5 may be used to balance the first moment of gravity T_aI.e. the first balancing moment and the first gravity moment T_aEqual in size,The directions are opposite; the second balancing moment generated by the second balancing mechanism 9 on the second joint 5 can then be used to balance the second moment of gravity T_bI.e. the second balance moment and the second gravity distance T_bEqual in size and opposite in direction.

In some embodiments, referring to FIG. 6, let the spring constant of the first balancing spring 81 be K₁Elongation of Deltax₁The first balance spring 81 generates a first spring tension F under the traction of the first balance rope 82₁First spring tension F₁The length of the moment arm relative to the second joint 5 is h₁The first guide mechanism 83 and the second guide mechanism 84 are located at E, F, respectively.

First spring tension F₁A first counter moment T generated to the second joint 5_cThe following were used:

T_c＝F₁×h₁ (10)

wherein, F₁＝K₁×Δx₁。

Area S of triangle formed by A, E, F points_ΔAEFEquality, one can conclude that:

wherein L is_AEThe distance between the second joint 5 and the first guide mechanism 83; l is_AFIs the distance, L, between the second joint 5 and the second guide mechanism 84_EFThe distance between the first guide mechanism 83 and the second guide mechanism 84; and L is_EF＝Δx₁。

From equation (11) it follows:

thus, the first balancing moment T_cComprises the following steps:

as can be seen from equations (8) and (13), the first counter torque T_cAt a first gravity distance T_aAre all in accordance with cos θ₂Is correlated by making T_c＝T_aThat is, the first balance moment T can be realized_cFor the first gravity distance T_aBalancing of (2). Further, it can be derived that:

from the equation (14), when the serial robot 100 is designed, G₂、

G₃、

G₄、L_ACAre all constants, and can therefore be based on G₂、

G₃、

G₄、L_ACAppropriate setting of the positions E, F of the first guide 83, the second guide 84 and the selection of the appropriate spring constant K of the first balancing spring 81₁。

In some embodiments, when the positions E, F of the first and second guide mechanisms 83, 84 are determined, an appropriate spring can be selected as the first balancing spring 81 according to equation (14), i.e., the spring constant of the first balancing spring 81

In some embodiments, when the first balancing force is equal to the first balancing force, as can be seen from equation (13)Moment T_cAt a first gravity distance T_aIf there is a deviation in the magnitude, the first compensation torque T can be adjusted by adjusting the position of the first guide 83 and/or the second guide 84_cOf such a magnitude that the first balancing moment T_cAt a first gravity distance T_aAre completely equal to each other, so as to ensure the first balance moment T_cCapable of fully balancing the first gravity distance T_a。

Further, 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 said first balancing link 6 may be made adjustable. In some embodiments, the position E of the first guiding mechanism 83 on the first link 2 may be made adjustable, and the position F of the second guiding mechanism 84 on the first balancing link 6 may be made non-adjustable. In some embodiments, the position E of the first guiding mechanism 83 on the first link 2 may be made non-adjustable and the position F of the second guiding mechanism 84 on said first balancing link 6 may 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 balancing link 6 may be adjustable.

By way of example only, as shown in fig. 5, the position E of the first guide mechanism 83 on the first link 2 is adjustable, and the position F of the second guide mechanism 84 on the first balancing link 6 is not adjustable. Specifically, the first guide mechanism 83 may include a first guide wheel 831 and a first bracket 832, the first bracket 832 is fixedly connected with the first link 2, and the first guide wheel 831 is rotatably connected with 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 with the second slider 842, and the second slider 842 is slidably connected with the first balance link 6.

In some embodiments, the first balance link 6 is provided with a first fixing block 61 and a bolt 62, the bolt 62 is screwed with the first fixing block 61, and one end of the bolt 62 is fixedly connected with the first slider 842, and the position adjustment of the second guide mechanism 84 on the first balance link 6 can be realized by screwing or unscrewing the bolt 62.

In some embodiments, referring to FIG. 7, a second counterbalance spring 91 is providedSpring constant K₂Elongation of Δ x₂The second balance spring 91 generates a second spring tension F under the traction of the second balance rope 92₂Second spring tension F₂A moment arm length h relative to the second joint 5₂The third guide mechanism 93 and the fourth guide mechanism 94 are located at positions G, H, respectively.

Second spring tension F₂A second counter moment T generated to the second joint 5_dThe following were used:

T_d＝F₂×h₂ (15)

wherein, F₂＝K₂×Δx₂。

Area S of triangle formed by A, G, H points_ΔAGHEquality, one can conclude that:

wherein L is_AGThe distance between the second joint 5 and the third guide mechanism 93; l is a radical of an alcohol_AHIs the distance between the second joint 5 and the fourth guide 94, L_GHThe distance between the third guide mechanism 93 and the fourth guide mechanism 94; and L is_GH＝Δx₂。

From equation (16), it follows:

thus, the second equilibrium moment T_dComprises the following steps:

as can be seen from equations (9) and (18), the second balancing moment T_dWith a second moment of gravity T_bAre all equal to sin theta₁Correlation by T_d＝T_bI.e. a second equilibrium moment can be achievedT_dWith a second moment of gravity T_bBalancing of (1). Further, it can be found that:

from the equation (19), when the serial robot 100 is designed, G₁、

G₂、L_AB、G₄、

Are all constants, and can therefore be based on G₁、

G₂、L_AB、G₄、

Appropriate setting of the positions G, H of the third guide 93 and the fourth guide 94 and selection of the spring constant K of the second balancing spring 91₂。

In some embodiments, when the positions G, H of the third and fourth guiding mechanisms 93 and 94 are determined, an appropriate spring can be selected as the second balance spring 91 according to equation (19), that is, the spring constant of the second balance spring 91

In some embodiments, as can be seen from equation (18), when the second balancing torque T is applied_dDistance of gravity from second gravity T_bIf there is a deviation in the magnitude, the second balancing moment T can be adjusted by adjusting the position of the third guide 93 and/or the fourth guide 94_dSo that the second equilibrium moment T_dDistance of gravity from second gravity T_bAre completely equal to each other, ensuring the second balance moment T_dCapable of fully balancing the second gravity distance T_b。

Further, the position G of the third guide mechanism 93 on the first link 2 and/or the position H of the fourth guide mechanism 94 on the second link 32 may be made adjustable. As to 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 may be made to the related description of 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 balancing link 6 being adjustable, and details are not repeated here.

In some embodiments, in order to ensure that the first spring tension and the second spring tension can generate the first balance moment and the second balance moment on the second joint 5 respectively, the second link 32 rotates around the second joint 5 by an angle θ₁Can be in the range of

The first balance connecting rod 6 rotates around the second joint 5 by an angle theta₂Can be in the range of

Wherein the counterclockwise rotation is positive and the clockwise rotation is negative. By limiting the rotation of the second connecting rod 32 and the first balance connecting rod 6 within the corresponding angle range, the moment arms of the first spring tension and the second spring tension relative to the second joint 5 can be ensured to exist all the time, so that the first spring tension and the second spring tension can generate a first balance moment and a second balance moment on the second joint 5 respectively all the time, and the directions of the first balance moment and the second balance moment are unchanged all the time, namely, the directions of the first balance moment and the second balance moment are opposite to the direction of the gravity distance at the second joint 5 all the time.

FIG. 8 is a schematic diagram of a tandem robot arm having a linkage assembly including only one linkage according to some embodiments of the present disclosure. As shown in fig. 8, in the tandem robot arm 200, the link assembly 3 includes only the second link 32, and the second link 32 is rotatably connected to the first link 2 by the second joint 5. The gravity balance assembly may only comprise one balance mechanism 10, and the balance mechanism 10 can generate a balance moment for the second joint, and the balance moment can be used for balancing the gravity moment generated by the second connecting rod 32 for the second joint 5, so that the second connecting rod 32 is in complete balance, and thus, the gravity complete balance of the serial mechanical arm is realized.

In some embodiments, the balancing mechanism 10 may include a balancing spring 11, a balancing cord 12, a first guide mechanism 13, and a second guide mechanism 14. One end of the balance spring 11 is fixedly connected to the first connecting rod 2, the other end of the balance spring 11 is fixedly connected to one end of the balance rope 12, the first guide mechanism 13 is arranged on the first connecting rod 2 and used for guiding the other end of the balance rope 12 to the second guide mechanism 14, and the second guide mechanism 14 is arranged on the second connecting rod 32 and used for guiding and connecting the other end of the balance rope 12 to the second connecting rod 32 or the second joint 5. Further description regarding the first guide mechanism 13 and the second guide mechanism 14 may refer to the related description of the first guide mechanism 83 and the second guide mechanism 84.

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 on the second link 32 or the second joint 5 by a fixed tightening mechanism to achieve connection. Further description of the fixed tightening mechanism may refer to the related description of the first fixed tightening mechanism 85.

With the above arrangement, 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 balance moment on the second joint 5. Specifically, the portion of the balancing cord 12 located between the first guide mechanism 13 and the second guide mechanism 14 is subjected to a spring tension, which can generate a balancing moment on the second joint 5. Wherein the elongation of the balancing spring 81 is the same as the distance between the first guide mechanism 13 and the second guide mechanism 14 (i.e., the length of the balancing cord 82 between the first guide mechanism 13 and the second guide mechanism 14).

The balance principle will be described in detail below with reference to the force diagram of the serial robot 200.

Fig. 9 is a force-receiving schematic diagram of the second link shown in fig. 8 when the second link rotates around the second joint by a certain angle.

Let the angle of rotation of the second link 32 about the second joint 5 be θ₁(ii) a The gravity of the second link 32 is G₁(ii) a The second link 32 has a center of mass of O₁(ii) a The gravity moment generated by the gravity of the second connecting rod 32, the third connecting rod 33, the first balance connecting rod 6 and the second balance connecting rod 7 on the second joint 5 is T₁、T₂、T₃、T₄(ii) a A. B, C are the positions of the second joint 5, the first guide mechanism 13, and the second guide mechanism, respectively.

As shown in fig. 9, the gravity distance to be balanced by the tandem robot arm 200 is the gravity distance generated by the gravity of the second link 32 to the second joint 5, i.e., has the same expression as the expression (2), and thus the tandem robot arm 200 needs the balanced gravity distance T₁Comprises the following steps:

since the tandem robot arm 200 shown in fig. 8 may be equivalent to the tandem robot arm 100 in fig. 2 without the third link 33, the first balance link 6, and the second balance link 7, the balance mechanism 10 may be equivalent to the second balance mechanism 9 of the tandem robot arm 100, that is, the balance moment generated by the balance mechanism 10 to the second joint 5 has the same expression as that of equation (18). Therefore, the balance moment T generated by the balance mechanism 10 to the second joint 5₂Comprises the following steps:

T₂＝K×L_AB×L_AC×sinθ₁ (21)

the balance moment T generated by the balance mechanism 10 to the second joint 5₂The gravity distance T to be balanced with the tandem robot arm 200₁The same size can be obtained, and the elastic constant of the balance spring 11

That is, in the case where the robot arm body of the serial robot arm 200 has been designed, and after the positions of the first guide mechanism 13 and the second guide mechanism 14 are determined, it is possible to determine the elastic constant based on the elastic constant

A suitable spring is selected as the balancing spring 11.

Since the balance mechanism 10 may correspond to the second balance mechanism 9, further description of the balance mechanism 10 may refer to the related description of the second balance mechanism 9, and will not be repeated herein.

It should be noted that, in the serial robot arm 100 or 200, considering that the link assembly 3 may also include the actuator, when designing the serial robot arm 100 or 200, for example, selecting the balance spring according to the spring constant, the weight of the third link 33 in the serial robot arm 100 or the weight of the actuator in the serial robot arm 200 should be included in addition to the self weight.

The beneficial effects that may be brought by the embodiments of the present specification include, but are not limited to: (1) the tandem mechanical arm provided by the embodiment of the specification realizes complete gravity balance by arranging the gravity balance assembly on the mechanical arm body, the gravity balance assembly generates the balance torque through the spring, the structure is simple, the weight is light, more inertia force cannot be increased, the flexibility and the operation precision of the tandem mechanical arm are hardly influenced, and an operator can be ensured to have better operation experience; (2) the balance mechanism in the gravity balance assembly in the embodiment of the specification can generate a first balance moment and a second balance moment to balance a first gravity moment and a second gravity moment which need to be balanced in the serial mechanical arm respectively, so that the decoupling of the nonlinear relation of the gravity moment which needs to be balanced in the serial mechanical arm to a rotation angle is realized, and the serial mechanical arm can realize the gravity complete balance under any posture in a motion space of the serial mechanical arm; (3) the second connecting rod, the third connecting rod, the first balance connecting rod and the second balance connecting rod are rotatably connected to form a parallelogram structure, so that the gravity distance of the series mechanical arm to be balanced can be concentrated at the second joint, the arrangement position of a driving structure of the series mechanical arm is flexible, and the structure of the series mechanical arm can be more compact; (4) the principle of gravity complete balance in the embodiment of the present description may be applied not only to a tandem robot arm, but also to a three-degree-of-freedom robot arm (i.e., a link assembly includes one link), and to a six-degree-of-freedom robot arm (i.e., a link assembly includes two links).

It is to be noted that different embodiments may produce different advantages, and in different embodiments, any one or combination of the above advantages may be produced, or any other advantages may be obtained.

Having thus described the basic concept, it will be apparent to those skilled in the art that the foregoing detailed disclosure is to be regarded as illustrative only and not as limiting the present specification. Various modifications, improvements and adaptations to the present description may occur to those skilled in the art, although not explicitly described herein. Such modifications, improvements and adaptations are proposed in the present specification and thus fall within the spirit and scope of the exemplary embodiments of the present specification.

Also, the description uses specific words to describe embodiments of the description. Reference throughout this specification to "one embodiment," "an embodiment," and/or "some embodiments" means that a particular feature, structure, or characteristic described in connection with at least one embodiment of the specification is included. Therefore, it is emphasized and should be appreciated that two or more references to "an embodiment" or "one embodiment" or "an alternative embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, some features, structures, or characteristics of one or more embodiments of the specification may be combined as appropriate.

Additionally, the order in which the elements and sequences of the process are recited in the specification, the use of alphanumeric characters, or other designations, is not intended to limit the order in which the processes and methods of the specification occur, unless otherwise specified in the claims. While various presently contemplated embodiments have been discussed in the foregoing disclosure by way of example, it should be understood that such detail is solely for that purpose and that the appended claims are not limited to the disclosed embodiments, but, on the contrary, are intended to cover all modifications and equivalent arrangements that are within the spirit and scope of the embodiments herein. For example, although the system components described above may be implemented by hardware devices, they may also be implemented by software-only solutions, such as installing the described system on an existing server or mobile device.

Similarly, it should be noted that in the foregoing description of embodiments of the specification, various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure aiding in the understanding of one or more of the embodiments. This method of disclosure, however, is not intended to imply that more features than are expressly recited in a claim. Indeed, the embodiments may be characterized as having less than all of the features of a single embodiment disclosed above.

Numerals describing the number of components, attributes, etc. are used in some embodiments, it being understood that such numerals used in the description of the embodiments are modified in some instances by the use of the modifier "about", "approximately" or "substantially". Unless otherwise indicated, "about", "approximately" or "substantially" indicates that the number allows a variation of ± 20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximations that may vary depending upon the desired properties of the individual embodiments. In some embodiments, the numerical parameter should take into account the specified significant digits and employ a general digit-preserving approach. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the range are approximations, in the specific examples, such numerical values are set forth as precisely as possible within the scope of the application.

For each patent, patent application publication, and other material, such as articles, books, specifications, publications, documents, etc., cited in this specification, the entire contents of each are hereby incorporated by reference into this specification. Except where the application history document does not conform to or conflict with the contents of the present specification, it is to be understood that the application history document, as used herein in the present specification or appended claims, is intended to define the broadest scope of the present specification (whether presently or later in the specification) rather than the broadest scope of the present specification. It is to be understood that the descriptions, definitions and/or uses of terms in the accompanying materials of this specification shall control if they are inconsistent or contrary to the descriptions and/or uses of terms in this specification.

Finally, it should be understood that the embodiments described herein are merely illustrative of the principles of the embodiments of the present disclosure. Other variations are also possible within the scope of the present description. Thus, by way of example, and not limitation, alternative configurations of the embodiments of the specification can be considered consistent with the teachings of the specification. Accordingly, the embodiments of the present description are not limited to only those embodiments explicitly described and depicted herein.

Claims (15)

1. A tandem robot arm, comprising: the mechanical arm comprises a mechanical arm body and a gravity balance assembly;

the mechanical arm body comprises a base, a first connecting rod and a connecting rod assembly; the base, the first connecting rod and the connecting rod assembly are sequentially connected in a rotating mode through a first joint and a second joint;

the gravity balance assembly comprises at least one balancing mechanism capable of generating at least one balancing moment to the second joint; the at least one balancing moment is at least used for balancing a gravity moment generated by the gravity of the connecting rod assembly on the second joint so as to enable the connecting rod assembly to be in complete balance.

2. The tandem robot arm of claim 1, wherein the linkage assembly comprises a second link and a third link rotationally connected by a third joint; the gravity balance assembly further comprises a first balance connecting rod and a second balance connecting rod; portions of the first balance link, the second link, and the third link are rotationally connected to form a parallelogram structure; wherein the content of the first and second substances,

one end of the second connecting rod is rotationally connected with one ends of the first connecting rod and the first balance connecting rod through the second joint, and the other end of the second connecting rod is rotationally connected with the third connecting rod through the third joint; one end of the first balance connecting rod is rotatably connected with the second connecting rod through the second joint, the other end of the first balance connecting rod is rotatably connected with one end of the second balance connecting rod, and the other end of the second balance connecting rod is rotatably connected to the third connecting rod;

the angle by which the third link can be rotated about the third joint by the parallelogram structure is determined by the angle by which the second link is rotated about the second joint and the angle by which the first balance link is rotated about the second joint.

3. The tandem robot arm of claim 2, wherein the gravity balance assembly comprises 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 for balancing the gravity moment generated by the gravity of the second connecting rod, the third connecting rod, the first balance connecting rod and the second balance connecting rod on the second joint; wherein

The first balancing moment is related to at least an angle of rotation of the first balancing link about the second joint, and the second balancing moment is related to at least an angle of rotation of the second link about the second joint.

4. The tandem arm assembly of claim 3 wherein the second joint comprises first and second oppositely disposed half shafts of rotation; one end of the second connecting rod is fixedly connected with the first rotating half shaft; one end of the first balance connecting rod is fixedly connected with the second rotary half shaft.

5. The tandem arm of claim 4 wherein the first counterbalance mechanism comprises a first counterbalance spring, a first counterbalance rope, a first guide mechanism, a second guide 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 with one end of the first balance rope; the first guide mechanism is provided on the first link to guide the other end of the first balance rope to the second guide mechanism, and the second guide mechanism is provided on the first balance link to guide the other end of the first balance rope to be connected to the first rotary half shaft;

the first balance spring is in an extension 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 content of the first and second substances,

the elongation of the first balance spring is the same as the distance between the first guide mechanism and the second guide mechanism.

6. The tandem arm of claim 5 wherein the first balance mechanism further comprises a first balance cord fixed take-up mechanism for fixed take-up of the other end of the first balance cord on the first rotary axle shaft.

7. The tandem arm of claim 5 wherein the position of the first guide mechanism on the first link and/or the position of the second guide mechanism on the first counter link is adjustable.

8. The tandem arm of claim 4 wherein the second counterbalance mechanism comprises a second counterbalance spring, a second counterbalance rope, a third guide mechanism, a fourth guide mechanism; one end of the second balance spring is fixedly connected to the first connecting rod, the other end of the second balance spring is fixedly connected with one end of the second balance rope, the third guide mechanism is arranged on the first connecting rod and used for guiding the other end of the second balance rope to the fourth guide mechanism, the fourth guide mechanism is arranged on the second connecting rod and used for guiding and connecting the other end of the second balance rope to the second connecting rod or the second rotating half shaft,

the second balance spring is in an extension state under the traction of the second balance rope and generates a second spring tension, and the second spring tension can generate a second balance moment on the second joint; wherein

The elongation of the second balance spring is the same as the distance between the third guide mechanism and the fourth guide mechanism.

9. The tandem arm of claim 8 wherein the second balance mechanism further comprises a second balance rope fixed tightening mechanism for fixedly tightening the other end of the second balance rope on the second link or the second rotating half shaft.

10. The tandem arm of claim 8 wherein the position of the third guide mechanism on the first link and/or the position of the fourth guide mechanism on the second link is adjustable.

11. The tandem arm of claim 5 wherein the spring constant of the first counter spring

Wherein the content of the first and second substances,

K₁is the spring constant of the first balance spring, G₂Is the weight force of the third connecting rod,

is the distance, G, between the third joint and the center of mass of the third link₃In order to balance the weight force of the link,

is the distance, G, between the second joint and the center of mass of the first balance link₄Is the gravity of the second balance link, L_ACIs the length, L, of the first balancing link_AEIs the distance, L, between the first guide mechanism and the second joint_AFIs the distance between the second guide mechanism and the second joint.

12. The tandem arm of claim 8 wherein the second counter spring has a spring constant

Wherein the content of the first and second substances,

K₂is the spring constant of the second balance spring, G₁Is the gravity of the second connecting rod,

is the distance, G, between the second joint and the center of mass of the second link₂Is the gravity of the third link, L_ABLength of said second link, G₄In order to balance the weight force of the link,

is the distance between the connecting point between the first and second balance connecting rods and the center of mass of the second balance connecting rod, L_AGIs the distance, L, between the third guide mechanism and the second joint_AHIs the distance between the fourth guide mechanism and the second joint.

13. The tandem robot arm of claim 1, wherein the linkage assembly comprises a second linkage that is rotationally coupled to the first linkage via the second joint;

the gravity balance assembly comprises a balance mechanism, the balance mechanism can generate a balance moment on the second joint, and the balance moment is used for balancing the gravity moment generated by the gravity of the second connecting rod on the second joint.

14. The tandem robot arm of claim 13, wherein the counterbalance mechanism comprises a counterbalance spring, a counterbalance rope, a first guide mechanism, a second guide mechanism; one end of the balance spring is fixedly connected to the first connecting rod, the other end of the balance spring is fixedly connected with one end of the balance rope, the first guide mechanism is arranged on the first connecting rod and used for guiding the other end of the balance rope to the second guide mechanism, and the second guide mechanism is arranged on the second connecting rod and used for guiding and connecting the other end of the balance rope to the second connecting rod;

the balance spring is in an extension state under the traction of the balance rope and generates spring tension, and the spring tension can generate the balance moment on the second joint; wherein the content of the first and second substances,

the balance spring has the same elongation as the distance between the first guide mechanism and the second guide mechanism.

15. The tandem arm of claim 14 wherein the spring constant of the counterbalance spring

Wherein the content of the first and second substances,

k is the spring constant of the balancing spring, G₁Is the gravity of the second connecting rod,

is the firstDistance between the two joints and the center of gravity of the second link, L_ABIs the distance, L, between the first guide mechanism and the second joint_ACIs the distance between the second guide mechanism and the second joint.

Images