Robot limb joint driving structure and design method

Abstract

The invention belongs to the technical field of robots, and particularly relates to a robot limb joint driving structure and a design method. The driving structure comprises an upper limb portion, a lower limb portion and a rigid chain device, the bottom end of the upper limb portion is hinged to the top end of the lower limb portion through a first hinge shaft, the rigid chain device is installed on the upper limb portion, a rigid chain output by the rigid chain device moves along an arc-shaped track around the first hinge shaft, and the head of the rigid chain is connected with the lower limb portion. The design method comprises the steps of determining a first rotation track, a second rotation track and a third rotation track and designing the sheet type of the chain plate. According to the invention, a joint motor module and a linear actuator can be effectively replaced, the structure not only has extension rigidity, but also can present specific bending degree, can bypass a joint pivot and directly act on a driven part, and the effect of driving rotation by a large force arm is realized on the premise of not increasing the structure size; and the defects of a robot limb joint driving mode are overcome.

Description

Technical Field

[0001] The present invention belongs to the technical field of robots, and in particular relates to a robot limb joint drive structure and a design method. Background Art

[0002] There are two types of driving modes for the robot's limb joints. Taking the leg structure as an example, they are joint motor module drive and linear actuator drive.

[0003] (1) The joint motor module drive method has a simple structure. It only needs to be used at the knee joint to connect the thigh and calf. However, due to the limitation of joint direct drive, it is often necessary to arrange a motor with larger power and size to meet the long-distance end force of the leg, which makes the leg structure larger and unable to withstand the force of large loads.

[0004] (2) The linear actuator driving method has high transmission accuracy and large load capacity. It is often placed in the limbs of the thigh or calf. With the help of the lever principle, the thrust is converted into torque to drive the movement of the next joint. However, the rear fixed end and the front driving end of this driving method need to be hinged, resulting in the linear actuator itself being in a follow-up non-stationary state during the movement, which seriously affects the coordination of the leg. In addition, in order to meet the lever structure, the driven component needs to be provided with an extension structure connected to the linear actuator, which makes the size of the joint larger and cannot well adapt to the design requirements of humanoid size. Summary of the Invention

[0005] The present invention discloses a robot limb joint drive structure and design method, which can effectively replace the joint motor module and linear actuator. The structure not only has extension rigidity, but also can present a specific curvature. It can bypass the joint hub and directly act on the driven component. Without increasing the structural size, it can achieve the effect of large-scale arm driven rotation, thus making up for the shortcomings of the robot limb joint drive method.

[0006] To achieve the above object, the technical solution of the present invention is:

[0007] A robot limb joint drive structure includes an upper limb, a lower limb, and a rigid chain device. The bottom end of the upper limb and the top end of the lower limb are hinged via a hinge axis. The upper limb is equipped with a rigid chain device. The rigid chain output by the rigid chain device moves along a circular arc trajectory around the hinge axis and is connected to the lower limb at the head of the rigid chain.

[0008] Preferably, the rigid chain device includes a shell arranged on the inner side of the upper part of the limb and fixedly connected to the upper part of the limb, and guide rail 1 and guide rail 2 are respectively provided on both sides of the inner wall of the shell, and chain 1 and chain 2 are respectively slidably connected to the guide rail 1 and guide rail 2, and an output port is provided at one end of the shell facing the lower part of the limb, and chain 1 and chain 2 are meshed with each other near the output port to form a rigid chain, and the rigid chain as a whole has an arc-shaped chain structure, and the arc-shaped chain structure has the same axis as the hinge shaft 1, and a sprocket is provided inside the shell and on the side of chain 1 close to the output port, and the sprocket is meshed with chain 1, and the central axis of the sprocket passes through the shell and is fixedly connected to the output shaft of the driving motor preset outside the shell, and the heads of chain 1 and chain 2 are commonly fixedly connected to a joint, and the joint is hinged to the lower part of the limb.

[0009] Preferably, the rigid chain adopts an engaged push chain system disclosed in the utility model with application number CN202321451294.0, the difference being that: the back of the chain plates of chain one and chain two are inclined surfaces, and while the front of chain one and chain two are connected by means of locks, the adjacent chain plates of chain one and chain two are fitted together by two inclined surfaces, thereby realizing the arc-shaped chain structure of the rigid chain; the chain plates of chain one and chain two are engaged by a single buckle or a double buckle.

[0010] Preferably, the joint is hinged to the lower part of the limb through the hinge axis 2, the cross-section of the axis of the hinge axis 2 rotating around the hinge axis 1 constitutes the rotation trajectory 1, the cross-section of the axis of the chain plate hole of the chain plate of chain 2 rotating around the hinge axis 1 constitutes the rotation trajectory 2, the cross-section of the axis of the chain plate hole of the chain plate of chain 1 rotating around the hinge axis 1 constitutes the rotation trajectory 3, and the distance A between the rotation trajectory 1 and the rotation trajectory 2 and the distance B between the rotation trajectory 1 and the rotation trajectory 3 are the same.

[0011] A method for designing a robot limb joint drive structure comprises the following steps:

[0012] Step 1: Based on the total load of the lower limb and the end structure connected to the lower limb, select a rigid chain that meets the load requirements and set the standard pitch of chain 2 to P A , the standard pitch of chain one is P B The width of the meshed chain 2 and chain 1 is W, where the width refers to the vertical distance between the connecting lines of the two meshed chain plates of chain 1 and chain 2;

[0013] Step 2: Set the axis of the hinge axis 1 as E and the axis of the hinge axis 2 as N. Determine that the cross section of the axis N along with the rotation of the lower part of the limb forms the first rotation track. Set the radius of rotation of the first rotation track as R, and the radius of rotation of the second rotation track as R. A =R+W / 2, the radius of rotation R of the rotation trajectory three B= = RW / 2, from this we can conclude that the standard pitch P of chain 1 B =P A *R B / R A ;

[0014] Step 3: On the second rotation track, with standard pitch P A For the chord length, design the locking structure on the front of the chain plate of chain 2 and the angle of the inclined surface on the back;

[0015] Step 4: On the rotation track 3, use P B = is the chord length, and the angle between the locking structure on the front and the inclined surface on the back of the chain plate of chain 2 is used as the reference. The locking structure on the front and the inclined surface angle on the back of the chain plate of chain 1 are designed in the form of difference set. At this point, the chain plate shape of chain 2 and chain 1 has been determined, and the sleeve, roller and pin parts of the rigid chain are designed based on this.

[0016] Step 5: Based on the required extension stroke of the rigid chain device, design the chain lengths of chain one and chain two and their storage and running tracks in the housing to complete the overall design of the arc-shaped rigid chain.

[0017] The beneficial effects of the robot limb joint drive structure and design method of the present invention are:

[0018] (1) The present invention proposes a driving scheme for robot limb joints, which can make up for the shortcomings of the direct drive mode of the joint motor module, such as the large motor power required and the large joint structure size. At the same time, it can solve the problem that the linear actuator can only run with the joint and cannot be fixed and stably transmitted.

[0019] (2) The driving scheme of the robot limb joint proposed in the present invention can achieve rigid bending, increase the driving force arm of the upper and lower limb articulated pairs, and improve the load-bearing capacity.

[0020] (3) The design method of the arc-shaped rigid chain proposed in the present invention can design the running trajectory of the mutually meshing rigid chain and the driven components according to the size structure of the joint, and has the advantage of high transmission accuracy.

[0021] (4) The arc-shaped rigid chain device proposed in the present invention can be arranged entirely within the trunk, and can bypass the hinge pairs of the upper and lower limbs during reciprocating motion, thereby greatly reducing the size of the joints. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is an overall structural diagram of the present invention taking the leg structure of a humanoid robot as an example.

[0023] Figure 2 This is the internal structure diagram of the rigid chain device.

[0024] Figure 3 The leg movement principle of the present invention is based on the leg structure of a humanoid robot as an example. Figure 1 .

[0025] Figure 4 The leg movement principle of the present invention is based on the leg structure of a humanoid robot as an example. Figure 2 .

[0026] Figure 5 This is a schematic diagram of the design of the chain plate type of the rigid chain according to the present invention.

[0027] 1. Rigid chain device; 1-1. Housing; 1-1-1. Guide rail one; 1-1-2. Guide rail two; 1-2. Rigid chain; 1-2-1. Chain two; 1-2-2. Chain one; 1-3. Sprocket; 1-4. Joint; 2. Thigh; 3. Calf; 4. Articulated shaft one; 5. Bolt hole one; 6. Bolt hole two; 7. Inclined surface; 8. Lock buckle; 9. Chain plate; 10. Rotation track two; 11. Rotation track three. DETAILED DESCRIPTION

[0028] The following description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0029] The following embodiments may be understood as individually expressing a part of a local structure or method of the present invention, or may be understood as a combination of the embodiments to explain the connotation of a larger structure or method of the present invention.

[0030] It should be noted that the robots involved in the present invention include humanoid robots and robots of various other forms, wherein the upper limbs and the lower limbs respectively refer to two upper and lower adjacent segments that constitute the limbs, such as the upper arm and the lower arm, the thigh and the calf, and the upper limbs and the lower limbs rotate around the pivot. The present invention is improved based on this rotational drive form.

[0031] In the drawings of the present invention, the leg structure of a humanoid robot is used as an example to provide an example of setting up a robot limb joint drive structure between the thigh and the calf. The same can be applied to other limbs.

[0032] The specific embodiments of the present invention will be described below with reference to the accompanying drawings:

[0033] Example 1

[0034] A robot limb joint drive structure, such as Figure 1-5As shown, it includes an upper limb, a lower limb, and a rigid chain device. The bottom end of the upper limb and the top end of the lower limb are hinged through a hinge shaft 4. The upper limb is equipped with a rigid chain device 1. The rigid chain 1-2 output by the rigid chain device 1 moves along a circular arc trajectory around the hinge shaft 4 and is connected to the lower limb at the head of the rigid chain.

[0035] In this embodiment, Figure 1-5 As shown, the thigh 2 of the humanoid robot's leg structure represents the upper limb, while the calf 3 represents the lower limb. Since the hinge axis 2 between the head of the rigid chain 1-2 and the lower limb rotates about the hinge axis 1-4 as the lower limb rotates, the rotational trajectory 1 of the axial cross-section of the hinge axis 2 is a circular trajectory coaxial with the hinge axis 1-4. The trajectory of the rigid chain 1-2 during extension and retraction is also assumed to lie within the circular arc trajectory around the hinge axis 1-4. Therefore, a rigid chain that satisfies this structure can achieve drive between the upper and lower limbs. Therefore, it can be understood that the present invention also provides a rigid chain device in which the extension trajectory of the rigid chain lies within a circular arc trajectory. This differs from conventional rigid chains that extend in a straight line, and also from some rigid chain devices that can extend in a curved manner but whose trajectory is uncertain. In other words, because the rigid chain of the present invention has a fixed extension trajectory, it is capable of performing precise transmission. This capability is difficult to achieve with a curved rigid chain with an unfixed extension trajectory.

[0036] Example 2

[0037] like Figure 1-4 As shown, the rigid chain device 1 includes a shell 1-1 arranged on the inner side of the upper part of the limb and fixedly connected to the upper part of the limb, and a guide rail 1-1-1 and a guide rail 2 1-1-2 are respectively provided on both sides of the inner wall of the shell 1-1, and a chain 1-2-2 and a chain 2 1-2-1 are respectively slidably connected to the guide rail 1-1-1 and the guide rail 2 1-1-2, and an output port is provided at one end of the shell 1-1 facing the lower part of the limb, and the chain 1-2-2 and the chain 2 1-2-1 are meshed with each other near the output port to form a rigid chain 1-2, and the rigid chain 1-2 as a whole It is an arc-shaped chain structure, and the arc-shaped chain structure has the same axis as the hinge shaft 4. A sprocket 1-3 is provided inside the shell 1-1 and on the side of the chain 1-2-2 close to the output port. The sprocket 1-3 is meshed and connected with the chain 1-2-2. The central axis of the sprocket 1-3 passes through the shell 1-1 and is fixedly connected to the output shaft of the drive motor (not shown) preset outside the shell 1-1. The heads of the chain 1-2-2 and the chain 2 1-2-1 are fixedly connected with a joint 1-4, and the joint 1-4 is hinged to the lower part of the limb.

[0038] In this embodiment, the rigid chain structure is conventional, typically comprising a housing, a guide rail disposed within the housing, and two chains capable of bending only to one side, which move along the guide rail and are housed within the housing. When the sprocket rotates, the two chains mesh together to form a rigid chain that is either extended outward or retracted into the housing. The rigid chain structure of the present invention may be a rigid chain device disclosed in the prior art that enables the rigid chain to extend and retract along a fixed circular arc trajectory.

[0039] Example 3

[0040] This embodiment provides an implementation of a rigid chain device, namely:

[0041] like Figure 1-5 As shown, the rigid chain adopts a meshing push chain system disclosed in the utility model application number CN202321451294.0, the difference being that: the back of the chain plates of chain one 1-2-2 and chain two 1-2-1 are inclined surfaces 7, and while the front of chain one 1-2-2 and chain two 1-2-1 are connected by means of a lock buckle 8, the adjacent chain plates of chain one 1-2-2 and chain two 1-2-1 are fitted together by two inclined surfaces 7, thereby realizing the arc-shaped chain structure of the rigid chain 1-2; the chain plates of chain one 1-2-2 and chain two 1-2-1 are meshed by a single buckle or a double buckle.

[0042] In this embodiment, the utility model with application number CN202321451294.0 discloses a meshing push chain system, the output push chain of which is a rigid straight push chain. The difference between the present invention and the system is that the output rigid chain has an arc-shaped trajectory by setting an inclined surface and a lock, the convex teeth at the meshing part can be double convex teeth or single convex teeth, and the chain can be in the form of a single-row chain or a double-row or multi-row chain.

[0043] Example 4

[0044] like Figure 1-5 As shown, the joint 1-4 is hinged to the lower part of the limb through the hinge shaft 2, the cross section of the axis of the hinge shaft 2 rotating around the hinge shaft 1-4 constitutes the rotation track 1, the cross section of the chain plate hole axis of the chain plate of the chain 2 1-2-1 rotating around the hinge shaft 1-4 constitutes the rotation track 2 10, the cross section of the chain plate hole axis of the chain plate of the chain 1-2-2 rotating around the hinge shaft 1-4 constitutes the rotation track 3 11, and the distance A between the rotation track 1 and the rotation track 2 10 and the distance B between the rotation track 1 and the rotation track 3 11 are the same.

[0045] Example 5

[0046] Based on the above embodiments, this embodiment discloses:

[0047] A design method for the driving structure of robot limb joints, such as Figure 1-5As shown, the following steps are included:

[0048] Step 1: If Figure 3 、 5 As shown in the figure, according to the total load of the lower part of the limb (such as the calf) and the end structure connected to the lower part of the limb (such as the sole of the foot), a rigid chain that meets the load requirements is selected, and the standard pitch of the chain 1-2-1 is set to P A The standard pitch of the chain 1-2-2 is P B The width of the meshed chain 1-2-1 and the meshed chain 1-2-2 is W, and the width refers to the vertical distance between the connecting lines of the two meshed chain plates of the meshed chain 1-2-2 and the meshed chain 2 1-2-1;

[0049] Step 2: Set the axis of the hinge axis 1 as E and the axis of the hinge axis 2 as N. Determine that the axis N forms a rotation trajectory 1 when the lower part of the limb rotates. Set the rotation radius of the rotation trajectory 1 as R (e.g. Figure 3 As shown), the radius of gyration of the second gyration trajectory is R A =R+W / 2, the radius of rotation R of the rotation trajectory three B = = RW / 2. To ensure that chain 2 1-2-1 and chain 1-2-2 can rotate around hinge axis 1-4 after meshing with each other, it is necessary to ensure that the pitch of the two chains relative to the central angle of hinge axis 1-4 is equal (e.g. Figure 5 As shown), it can be concluded that the standard pitch P of the chain is 1-2-2. B =P A *R B / R A ;

[0050] Step 3: On the second rotation track, with standard pitch P A For the chord length, the angle between the lock buckle 8 structure on the front of the chain plate and the inclined surface 7 on the back of the chain plate is designed in the second 1-2-1;

[0051] Step 4: On the rotation track 3, use P B The chord length is taken as the reference, and the angle of the front locking structure and the back inclined surface of the chain plate of chain 2 1-2-1 is used as the reference. The angle of the front locking structure and the back inclined surface of the chain plate of chain 1 1-2-2 is designed in the form of difference set. At this time, the chain plate shapes of chain 2 1-2-1 and chain 1 1-2-2 have been determined, and the sleeve, roller and pin parts of rigid chain 1-2 are designed based on this. Figure 5 As shown, after the shape and size of the adjacent chain plates of chain 2 are determined, the shape and size of the chain plates of chain 1 in the shaded part can be obtained;

[0052] Step 5: According to the required extension stroke of the rigid chain device 1, design the chain length of chain 1 1-2-1 and chain 2 1-2-2 and the storage running track in the shell (i.e. design guide rail 1 and guide rail 2) to complete the overall design of the arc-shaped rigid chain 1-2.

[0053] This embodiment provides a design method for a rigid chain device, based on which the drawing of a rigid chain device disposed between an upper limb and a lower limb and the manufacture of the rigid chain device can be realized.

Claims

1. A robot limb joint drive structure, characterized by: It includes an upper limb, a lower limb, and a rigid chain device. The bottom end of the upper limb and the top end of the lower limb are hinged through a hinge axis. The upper limb is equipped with a rigid chain device. The rigid chain output by the rigid chain device moves along a circular arc trajectory around the hinge axis and is connected to the lower limb at the head of the rigid chain.

2. A robot limb joint drive structure according to claim 1, characterized in that: The rigid chain device includes a shell arranged on the inner side of the upper part of the limb and fixedly connected to the upper part of the limb, and a guide rail 1 and a guide rail 2 are respectively provided on both sides of the inner wall of the shell, and a chain 1 and a chain 2 are respectively slidably connected to the guide rail 1 and the guide rail 2, and an output port is provided at one end of the shell facing the lower part of the limb, and the chain 1 and the chain 2 are meshed with each other near the output port to form a rigid chain, and the rigid chain as a whole has an arc-shaped chain structure, and the arc-shaped chain structure has the same axis as the hinge shaft 1, and a sprocket is provided inside the shell and on the side of the chain 1 close to the output port, and the sprocket is meshed with the chain 1, and the central axis of the sprocket passes through the shell and is fixedly connected to the output shaft of the driving motor preset outside the shell, and the heads of the chain 1 and the chain 2 are commonly fixedly connected with a joint, and the joint is hinged to the lower part of the limb.

3. A robot limb joint drive structure as claimed in claim 2, characterized in that: The rigid chain adopts an engaged push chain system, the difference being that the back of the chain plates of chain one and chain two are inclined surfaces. While the front of chain one and chain two are connected by means of a lock, the adjacent chain plates of chain one and chain two are fitted together by two inclined surfaces, thereby realizing the arc-shaped chain structure of the rigid chain; the chain plates of chain one and chain two are engaged by a single buckle or a double buckle.

4. A robot limb joint drive structure as claimed in claim 3, characterized in that: The joint is hinged to the lower part of the limb through the hinge axis 2. The cross-section of the axis of the hinge axis 2 rotating around the hinge axis 1 constitutes the rotation trajectory 1, the cross-section of the chain plate hole axis of the chain plate of chain 2 rotating around the hinge axis 1 constitutes the rotation trajectory 2, and the cross-section of the chain plate hole axis of the chain plate of chain 1 rotating around the hinge axis 1 constitutes the rotation trajectory 3. The distance A between the rotation trajectory 1 and the rotation trajectory 2 and the distance B between the rotation trajectory 1 and the rotation trajectory 3 are the same.

5. The method for designing a robot limb joint drive structure according to claim 4, characterized in that it comprises the following steps: Step 1: Based on the total load of the lower limb and the end structure connected to the lower limb, select a rigid chain that meets the load requirements and set the standard pitch of chain 2 to P A , the standard pitch of chain one is P B The width of the meshed chain 2 and chain 1 is W, where the width refers to the vertical distance between the connecting lines of the two meshed chain plates of chain 1 and chain 2; Step 2: Set the axis of the hinge axis 1 as E and the axis of the hinge axis 2 as N. Determine that the cross section of the axis N along with the rotation of the lower part of the limb forms the first rotation track. Set the radius of rotation of the first rotation track as R, and the radius of rotation of the second rotation track as R. A =R+W / 2, the radius of rotation R of the rotation trajectory three B = = RW / 2, from this we can conclude that the standard pitch P of chain 1 B =P A *R B / R A ; Step 3: On the second rotation track, with standard pitch P A For the chord length, design the locking structure on the front of the chain plate of chain 2 and the angle of the inclined surface on the back; Step 4: On the rotation track 3, use P B = is the chord length, and the angle between the locking structure on the front and the inclined surface on the back of the chain plate of chain 2 is used as the reference. The locking structure on the front and the inclined surface angle on the back of the chain plate of chain 1 are designed in the form of difference set. At this point, the chain plate shape of chain 2 and chain 1 has been determined, and the sleeve, roller and pin parts of the rigid chain are designed based on this. Step 5: Based on the required extension stroke of the rigid chain device, design the chain lengths of chain one and chain two and their storage and running tracks in the housing to complete the overall design of the arc-shaped rigid chain.

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