CN212399657U

CN212399657U - Flexible mechanical arm based on fluid multi-channel structure

Info

Publication number: CN212399657U
Application number: CN201922141896.6U
Authority: CN
Inventors: 崔祚; 薛九天
Original assignee: Guizhou Institute of Technology
Current assignee: Guizhou Institute of Technology
Priority date: 2019-12-04
Filing date: 2019-12-04
Publication date: 2021-01-26
Anticipated expiration: 2029-12-04

Abstract

The utility model discloses a flexible mechanical arm based on fluid multichannel structure, this scheme utilize fluid drive's multichannel structure to simulate flexible mechanical arm to change the deformation rigidity of arm through changing fluid pressure, realize the variable rigidity characteristic of flexible mechanical arm. Meanwhile, the flexible mechanical arm can realize the variable stiffness characteristic of the manufactured flexible mechanical arm through optimization of multi-channel structural parameters and fluid parameters, and better control performance is obtained. The flexible mechanical arm pose control method aims to solve the problem of accurate pose control of the flexible mechanical arm and provide effective variable stiffness control, and an effective engineering solution is provided for pose control of the flexible mechanical arm.

Description

Flexible mechanical arm based on fluid multi-channel structure

Technical Field

The utility model discloses mainly use the robot field specifically is a flexible arm based on fluid multichannel structure.

Background

With the continuous development of the robot technology, the mechanical arm is widely applied in various industries, particularly in the fields of intelligent manufacturing, industrial automation, aerospace and the like. In the traditional industrial field, the mechanical arm is driven by a rigid joint, the high-precision control of the position and the speed of the tail end can be realized, the motion trail is accurately tracked, and the response speed is high. However, the mechanical arm has the defects of large mass and volume, high output rigidity, weak adaptability to unknown environment and the like. However, when the mechanical arm is gradually applied to other non-industrial fields such as service, medical treatment and entertainment, the working environment at the tail end of the mechanical arm is often in contact, or when the mechanical arm is applied to unknown environments such as dangerous environment detection, that is, when special requirements such as a motion track of the mechanical arm cannot be planned in advance, the flexible mechanical arm is produced accordingly, and the flexible mechanical arm has the advantages of compact structure, good flexibility, higher load/dead weight ratio and better environment interaction capacity.

As new types of elastic elements or flexible mechanisms are increasingly applied to robotic arms, flexible arms with variable or continuously adjustable stiffness have emerged. The development of such flexible arms aims to be comparable with human arms in terms of dexterity and perceptibility, and eventually can gradually replace human work. Therefore, the research on the variable-stiffness mechanical arm with human muscle-like characteristics has important practical significance for improving the safety and environmental adaptability of the robot and better serving human beings in the future. In combination with technologies such as elastic mechanics, robotics, intelligent control and the like, bionic workers develop various different types of flexible mechanical arms.

The flexible mechanical arm has three driving modes of an embedded type, an external type and a mixed type according to different driver distribution conditions. The embedded type is driven by pneumatic muscle or Shape Memory Alloy (SMA) and is arranged inside the mechanical arm, for example, a pneumatic trunk type mechanical arm is developed by German Festo company. An "octopus tentacle" robotic arm developed by MIT Computer Science and Artificial Intelligence Laboratories (CSAIL). Makishi et al, northeast Japan university, developed a shape memory alloy-driven endoscopic robot, which can bend 45mm in part and carry a20 mm long CCD camera for endoscopic examination, and the maximum bending angle can reach 90 degrees. The external robot mainly drives a robot joint by pulling a cable by an external motor, such as a snake-shaped arm robot developed by OCRobotics of England, the robot has 10 sections, each section has 2 degrees of freedom, and the robot is driven by the motor. The hybrid drive has both an embedded drive structure and an external drive structure, such as an Air-inductor robot developed by McMahan et al, the hybrid drive has a structure divided into 4 sections, the bending angle of each section is greater than 100 degrees, and the robot introduces pneumatic drive and cable drive at the same time.

However, the structure of the existing flexible mechanical arm is still not mature enough, and for example, the defects of heavy weight, low flexibility, poor flexibility and the like require further innovative improvement.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a flexible arm based on multichannel fluid structure has advantages such as light in weight, the flexibility ratio is high and the compliance is good, can reduce joint rigidity by a wide margin, accomplishes complicated contact nature task.

The utility model provides a flexible mechanical arm structure utilizes the elastic deformation of viscoelastic material body in order to realize its continuous bending to form the motion of similar elephant nose, octopus tentacle. By changing the shape of the robot, the flexible robot can flexibly bypass various obstacles or pass through narrow and curved holes, and is very suitable for application in unstructured environments and space-limited environments. Besides, the flexible robot can also realize the grabbing of the object only through the body, similar to the action of the elephant grabbing food through the nose. The excellent performances enable the flexible robot to have great application prospects in the fields of aviation detection, medical surgery, urban rescue, industrial manufacturing, agricultural production and the like.

The utility model provides a flexible arm's flexibility mainly derives from joint flexibility and member flexibility, and they are the arm and introduced extra degree of freedom for original limited degree of freedom has become unlimited degree of freedom. The connecting rod of the flexible mechanical arm is rigid and flexible and only exists at the joint; the flexibility of a joint can be divided into active flexibility and passive flexibility. The active flexibility means that the joint has no flexibility, and the relationship between output force and output position is actively controlled by utilizing the sensing information, so that the flexible characteristic of the joint is simulated; passive flexibility refers to the incorporation of elastic elements into the structure to provide compliance to the structure.

The technical scheme of the utility model be utilize fluid drive's multichannel structure to simulate flexible arm to change the deformation rigidity of arm through changing fluid pressure, realize the variable rigidity characteristic of flexible arm. Meanwhile, the flexible mechanical arm can realize the variable stiffness characteristic of the manufactured flexible mechanical arm through optimization of multi-channel structural parameters and fluid parameters, and better control performance is obtained. The flexible mechanical arm pose control method aims to solve the problem of accurate pose control of the flexible mechanical arm and provide effective variable stiffness control, and an effective engineering solution is provided for pose control of the flexible mechanical arm.

The utility model discloses a flexible arm accessible changes the viscoelastic material's of arm physical attribute and realizes becoming rigidity characteristic, and its bending deformation depends on physical parameters such as the young's modulus of material, length and section moment of inertia. Thus, the variation in stiffness can be achieved by changing the physical parameter.

For the flexible mechanical arm, the influence of the rigidity of the established dynamic model on the whole bending deformation and the control of the tail end position of the flexible mechanical arm needs to be considered, namely, the rigidity of the flexible mechanical arm is reasonably designed and can be properly adjusted according to external environmental factors. At present, although research shows that the rigidity of the flexible mechanical arm has great influence on bending deformation, the relationship between the change situation of the rigidity of the flexible mechanical arm and parameters such as the bending deformation of the flexible mechanical arm is not clear. This also inspires that if the bending deformation of the flexible manipulator is to be controlled, the manipulator is developed to have not only a certain stiffness but also some way of adjusting the stiffness. The utility model discloses a deformation and the variable rigidity characteristic of arm are realized to multichannel structure based on fluid drive. Unlike traditional rigid mechanical arms, flexible mechanical arms do not have discrete joints or rigid connecting rods and cannot use traditional kinematic modeling methods. The elastic deformation of the flexible robot can be modeled by a curvature approximation model. In the curvature approximation model, assuming that the curved shape of the flexible robot is a combination of several constant curvature curves, the model has been widely used, with the advantages of simple calculation and easy understanding.

The utility model discloses except having traditional arm simple structure, with low costs, control is simple, and the motion space is big etc. advantage, still has the inherent compliance of flexible arm and better environment interaction ability. In addition, the rigidity of the whole mechanical arm can be changed, so that the rigidity of the contact interface of the mechanical arm and the environment can be matched in real time.

More specifically, the utility model discloses at least, include following part: the system comprises a flexible mechanical arm structure, a mechanical arm fixing platform, a rigid mechanical arm structure, a fluid multi-channel structure, a fluid driving system and a displacement or speed sensor; the upper end and the lower end of each flexible mechanical arm structure are respectively fixed on the rigid mechanical arm structure, and the lower end of each flexible mechanical arm structure penetrates through a hinge point hole on the rigid mechanical arm structure and is fixedly connected with the displacement or speed sensors; the flexible mechanical arm structure is used for changing the deformation curve or deformation displacement of the variable-rigidity mechanical arm structure, and the deformation condition depends on the number of channels of the fluid multi-channel structure and the pressure and flow rate of the fluid driving system.

As a further optimization of the technical solution, the multi-channel fluid flexible mechanical arm includes a channel dividing layer, a flexible channel, a fluid channel inlet and a fluid channel outlet. The channel division layer is made of a material which is not easy to deform and is mainly used for fixing a multi-channel subsystem (or a single-channel system) and separating each subsystem to carry out single-channel driving. Each single channel system presents a channel inlet and a channel outlet for the inflow and outflow of fluid in the channel.

Here, the flexible mechanical arm is based on a multi-channel structure, and bending deformation is achieved through hydraulic or pneumatic driving. The fluid driven multi-channel flexible mechanical arm can be composed of a plurality of sub-channels, and different array types and structural parameters exist.

The utility model discloses a flexible mechanical arm can have a plurality ofly, and flexible mechanical arm is more, and rigid mechanical arm is shorter, and this flexible mechanical arm warp more controllable, and mechanical arm control is also more accurate.

In addition, the variable stiffness of the flexible mechanical arm can realize the control of the bending stiffness by controlling the flow rate and the pressure of the fluid, and the stiffness control of the whole mechanical arm.

The utility model has the advantages that:

compare with the design method of current industry arm, the utility model discloses a variable rigidity arm of fluid drive multichannel flexible mechanical arm structure is through changing the pressure and the velocity of flow of the interior fluid of multichannel flexible mechanical arm to realize the deformation and the rigidity of flexible mechanical arm. The design can effectively improve the control performance of the flexible mechanical arm, and has important significance for wide application of the flexible mechanical arm. Therefore, the utility model discloses a technical scheme's advantage lies in:

(1) the fluid-driven multi-channel fluid system is adopted to achieve good flexibility and high flexibility of the mechanical arm, joint rigidity can be greatly reduced, and complex contact tasks are completed.

(2) The bending deformation and variable stiffness control of the flexible mechanical arm can be realized by changing the pressure of fluid in multiple channels in the flexible mechanical arm. By optimizing the structural size of a multi-channel system in the flexible mechanical arm, such as parameters of channel type, channel width, distance between channels and the like, the effective control of the bending deformation of the flexible mechanical arm can be realized.

(3) The flexible mechanical arm can be bent and deformed by changing the flow speed of fluid in multiple channels in the flexible mechanical arm. By optimizing the structural size of a multi-channel system in the flexible mechanical arm, such as parameters of channel type, channel width, distance between channels and the like, the effective control of the bending deformation of the flexible mechanical arm can be realized. The deformation is realized by a fluid driving system, stepless speed regulation can be conveniently realized, the speed regulation range is wide, and the speed can be regulated in the running process of the system.

(4) The driving is carried out through a hydraulic pump or an air pump, the driving is stable, large thrust or large torque is output, and the power is high. The fluid transmission system in the flexible mechanical arm has overload protection capability, and the transmission route is flexibly arranged.

(5) In the mechanical arm structure based on the fluid driving multi-channel structure, the fluid driving system can enable the flexible mechanical arm to deform uniformly and stably, and no reversing impact exists during reverse deformation. The fluid driving system has high reaction speed, is suitable for repeated reversing deformation of the flexible mechanical arm, is convenient to control, and is easy to realize automatic working circulation. The flexible arm based on fluid drive not only has the advantages of a light arm, but also has high power/mass ratio, good buffer function and the like.

Drawings

FIG. 1 is a general schematic view of a fluid-based multi-channel flexible robotic arm structure;

FIG. 2 is a schematic diagram of an undeformed state of a multi-channel flexible manipulator structure;

FIG. 3 is a schematic diagram of a deformation state of a multi-channel flexible mechanical arm structure;

FIG. 4 is a top view of a multi-channel flexible robotic arm structure;

FIG. 5 is a control system schematic;

FIG. 6 is a schematic diagram of a four-channel drive system for a multi-drive flexible robotic arm structure;

FIG. 7 is a top view of FIG. 6;

FIG. 8 is a schematic diagram of a six-channel drive system for a multi-drive flexible robotic arm structure;

FIG. 9 is a top view of FIG. 8;

fig. 10 is a schematic structural view of a fluid driving system of the flexible robot arm.

The labels in the figures are: 1-a fixed support, 2-a deformation arm deformation I section, 3-a deformation arm deformation II section, 4-a tail end execution part, 5-an energy accumulator, 6-an overflow valve, 7-a stop valve, 8-a stop check valve, 9-a pressure gauge, 10-a variable frequency pump, 11-a filter, 12-an oil tank, 13-a medium pressure gauge, 14-a pressure regulating valve, 15-an electric flow control valve, 16-a flowmeter, 17-an electromagnetic switch valve, 18-a differential pressure measuring gauge, 19-an electric valve, 20-a flexible arm fluid channel 1-a, 21-a flexible arm fluid channel 1-b, 22-a flexible arm fluid channel 1-c, 23-a flexible arm fluid channel 1-d, 24-a flexible arm fluid channel 2-a, 25-fluid channel 2-b of the flexible arm, 26-fluid channel 2-c of the flexible arm, 27-fluid channel 2-d of the flexible arm.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted", "provided", "sleeved/connected", "connected", and the like are to be understood in a broad sense, such as "connected", which may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The embodiment of the utility model provides a:

the embodiment is based on a flexible mechanical arm with a fluid driving multi-channel structure, and the flexibility and the rigidity changing characteristic of the mechanical arm are realized through a rigid part connected with the mechanical arm. In fig. 1, the present invention includes the following components: 1-fixed support 1, deformation arm deformation I section 2, deformation arm deformation II section 3 and end executive component 4.

In the specific design, the method comprises the following steps:

according to the design task of the mechanical arm, the trajectory planning of mechanical arm deformation is analyzed, the number of sections of the rigid mechanical arm and the length of each section of the mechanical arm are designed, and parameters such as the mass, the section size and the moment of inertia of each section of the mechanical arm are designed.

And designing a fluid-driven multi-channel flexible structure of the flexible mechanical arm according to the planned track of the mechanical arm. The multi-channel structure mainly comprises a flexible deformation channel and a hard boundary layer, and fluid flows in through holes of the hard boundary layer. The parameters of the flexible deformation channel mainly include channel height, channel width, channel gap and channel thickness. The corresponding structural diagrams of the multichannel in an undeformed state and a deformed state are respectively shown in the accompanying figures 2-4.

In the motion process, the flexible mechanical arm can generate vibration, and the generated micro-vibration can have great influence on the control of the mechanical arm. When the moving speed is high, the tail end of the flexible mechanical arm can generate a large pose error. In the variable stiffness structure research, the variable stiffness structure generally comprises a motor, a speed reducer, a variable stiffness element, a sensor, a controller and the like, and is a mechanical and electrical integration system with higher integration level. The rigid mechanical arm can accurately track a preset track, and after the rigid mechanical arm reaches a specified position, the output position of the mechanical arm cannot change along with the change of the load. Unlike rigid arms, variable stiffness arms can be allowed to deviate from the equilibrium position by an angle or distance depending on the magnitude of the external load. The specific control block diagram is shown in fig. 5.

The flexible mechanical arm based on the hydraulic drive multi-channel fluid structure can select a plurality of channel loops to realize independent control of different positions of the flexible mechanical arm, so that pitching, yawing, twisting and other motions of the mechanical arm are realized. As shown in fig. 6-7, multiple multi-channel fluid circuits may be selected, the fluid in each circuit being driven integrally by a fluid control system, and each channel circuit being precisely controlled by a separate control valve.

And selecting a hard boundary layer with a proper size and flexible multi-channel parameters, and pressing high-pressure fluid into the channel by using a hydraulic pump or an air pump to deform the channel and expand one side of the flexible mechanical arm. The flexible mechanical arm realizes deformation control movement through the reciprocating driving of high pressure and low pressure of a hydraulic system. The movement speed of the fluid in the channel determines the response speed of the deformation control of the flexible mechanical arm, and the pressure of the fluid in the channel determines the rigidity of the flexible mechanical arm.

The design of the multi-channel fluid structure can be further realized by combining the appearance parameters of the flexible mechanical arm and the size of the hard boundary layer. The different array types of the multiple channels are shown in the attached figures 8-9, and the bending deformation and the rigidity control of the mechanical arm with different degrees can be realized. The material of the multi-channel system will directly affect the deformation of the robot arm, and the array type of the channels and the channel parameters will directly affect the variable stiffness characteristics of the robot arm.

In the structure of the flexible mechanical arm, a multi-path hydraulic force transmission system is designed according to the number of channels of the flexible mechanical arm, so that variable rigidity control of the mechanical arm is realized. For each single channel system, different fluid channels are designed by using multiple hydraulic valves. In addition, the deformation of the multi-channel structure system is also influenced by the material characteristics, and the large-scale bending deformation and large-scale change of the bending rigidity of the flexible mechanical arm can be obtained according to the optimization of the channel structure parameters.

As shown in fig. 10, in the flexible mechanical arm of the present invention, the driving system is a hydraulic pump, and the control system is a valve control hydraulic system. The system comprises an energy accumulator 5, an overflow valve 6, a stop valve 7, a stop check valve 8, a pressure gauge 9, a variable frequency pump 10, a filter 11, an oil tank 12, a medium pressure gauge 13, a pressure regulating valve 14, an electric flow control valve 15, a flow meter 16, an electromagnetic switch valve 17, a differential pressure measuring gauge 18, an electric valve 19 and the like; in fig. 10, the fluid channel of the flexible arm is divided into: flexible arm fluid channel 1-a20, flexible arm fluid channel 1-b21, flexible arm fluid channel 1-c22, flexible arm fluid channel 1-d23, flexible arm fluid channel 2-a24, flexible arm fluid channel 2-b25, flexible arm fluid channel 2-c26, and flexible arm fluid channel 2-d 27.

These systems are used to control fluid flow rates and pressures in multi-channel fluid systems. High-pressure fluid generated by driving of the pump is pumped into the mechanical arm channel through multiple channels of the flexible mechanical arm, one side of the mechanical arm is extended by a high-pressure area of the fluid in the channel, and the other side of the mechanical arm is contracted by a low-pressure area, so that deformation control of the mechanical arm is realized. The part is simple in structure, small in size and high in control precision.

Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments or portions thereof without departing from the spirit and scope of the invention.

Claims

1. A flexible mechanical arm based on a fluid multi-channel structure is characterized in that: utilizing elastic deformation of the viscoelastic material body to realize continuous bending thereof; the flexibility is derived from joint flexibility and rod flexibility; at least comprises the following components: the system comprises a flexible mechanical arm structure, a mechanical arm fixing platform, a rigid mechanical arm structure, a fluid multi-channel structure, a fluid driving system and a displacement or speed sensor; the upper end and the lower end of each flexible mechanical arm structure are respectively fixed on the rigid mechanical arm structure, and the lower end of each flexible mechanical arm structure penetrates through a hinge point hole on the rigid mechanical arm structure and is fixedly connected with the displacement or speed sensors; the flexible mechanical arm structure is used for changing the deformation curve or deformation displacement of the rigid mechanical arm structure, and the deformation condition depends on the number of channels of the fluid multi-channel structure and the pressure and flow rate of the fluid driving system.

2. The flexible mechanical arm based on the fluid multi-channel structure as claimed in claim 1, wherein: the flexible mechanical arm is simulated by utilizing a multi-channel structure driven by fluid, and the deformation rigidity of the mechanical arm is changed by changing the fluid pressure, so that the rigidity changing characteristic of the flexible mechanical arm is realized.

3. The flexible mechanical arm based on the fluid multi-channel structure as claimed in claim 1, wherein: the variable stiffness characteristic is achieved by changing the physical properties of the viscoelastic material of the robotic arm.

4. The flexible mechanical arm based on the fluid multi-channel structure as claimed in claim 1, wherein: the fluid multi-channel structure comprises a channel partition layer, flexible sub-channels, fluid channel inlets and fluid channel outlets; the channel division layer is made of a material which is not easy to deform and is used for fixing a multi-channel subsystem or a single-channel system, separating the subsystems and carrying out single-channel driving; each single channel system presents a channel inlet and a channel outlet for the inflow and outflow of fluid in the channel.

5. The flexible mechanical arm based on the fluid multi-channel structure as claimed in claim 1, wherein: the flexible mechanical arm structure is based on the fluid multi-channel structure, and bending deformation is achieved through hydraulic or pneumatic driving.

6. The flexible mechanical arm based on the fluid multi-channel structure as claimed in claim 1, wherein: the fluidic multi-channel structure is composed of a plurality of sub-channels, with different array patterns and structural parameters.