CN108789395B

CN108789395B - Series viscoelastic driver based on bionic tendon

Info

Publication number: CN108789395B
Application number: CN201810580937.9A
Authority: CN
Inventors: 陈务军; 贾林睿; 敬忠良; 董鹏
Original assignee: Shanghai Jiaotong University
Current assignee: Shanghai Jiaotong University
Priority date: 2018-06-07
Filing date: 2018-06-07
Publication date: 2021-03-30
Anticipated expiration: 2038-06-07
Also published as: CN108789395A

Abstract

The invention discloses a series viscoelastic driver based on a bionic tendon, which relates to the technical field of mechanical engineering and comprises a driving steering engine, the bionic tendon, a rotary joint and a base. The driving steering engine and the rotating joint are fixedly installed on the base, and the driving steering engine is connected with the rotating joint through the bionic tendon. The invention provides a driver which has compact structure, simple operation, stable output and low cost, realizes flexible rotary motion in a compact form, realizes bidirectional flexible response similar to a biological motion system under the condition of ensuring precision, and can be used as a driving device of a bionic robot, an industrial manipulator and the like.

Description

Series viscoelastic driver based on bionic tendon

Technical Field

The invention relates to the technical field of mechanical engineering, in particular to a series viscoelastic driver based on bionic tendons.

Background

Generally, for a robot, it is required to have extremely high position control accuracy, which requires the robot to have high rigidity to obtain a sufficiently wide control bandwidth and reduce errors in position. This leads to such robots, being less than satisfactory in terms of force control: a small difference in position results in a large change in output force. On the other hand, through the cognition on the living beings, people find that the living beings have low precision on position control, and the precise position of the limb is difficult to control without the help of vision and touch. Instead, the organism shows a very strong adaptability in force control. The essential difference between the two results from the driving principle: most robots are driven by a motor, and transmission elements such as gears, connecting rods and the like are rigid structures; animals are mostly muscle-driven and are flexible biological tissues. In the process of realizing foot type movement, people gradually realize the importance of flexibility, and on the basis of understanding the principle of biological movement, a flexible and controllable bionic driver is designed and manufactured in a bionic mode, and the bionic driver plays an increasingly important role in realizing the movement of animals by a robot.

In the motor system of animals, skeletal muscle is the driver, which is composed of two parts, muscle belly and tendon, wherein the muscle belly is composed of muscle fiber and has contractility, while the tendon is a dense mustard pedicle tissue and only plays a role in traction connection without active contractility. The mechanical response of the muscle can be divided into two parts, one is an active response of the self-contraction generated by the nerve impulse to the external output force, and the other is a passive elastic response in a resting state. It has been found that biological muscles exhibit superelasticity in the quasi-static state and a non-linear viscoelastic effect during dynamic conditions.

Many developments have been made on conventional motors in order to achieve a dynamic muscle-like response.

In 1995, "Series Elastic Actuators [ C ]// International Conference on Intelligent Robots and systems, ieee Computer Society, 1995", proffered by Pratt professor to Williamson, to provide flexible control and force output by connecting Elastic units in Series between the motor and the load to form a Series Elastic Actuators (SEA), isolating the motor from the impact load, and filtering the effects of backlash, torque ripple, and friction through the Elastic units. Such actuators have a low impedance, precise force output, but relatively narrow control bandwidth, relatively more complex mechanical structure and electronic control.

"Series Elastic Actuators (SEAs) for Small-scale Robotic applications, journal of mechanics & Robotic, 2017" by Priyanshu Agarwal and Ashish D.Deshpand utilizes guy cable transmission and passes through wire spring and torsion spring respectively, thereby realizing SEA for separating a Small-scale driver from a joint and being successfully applied to the exoskeleton of a human hand.

A modular visco-elastic joint for an assisted pneumatic robot [ J ].2012 ", Dino Accoto et al, has an adjustable damping element utilizing liquid viscosity connected in parallel to an elastic unit, thereby realizing small-sized series viscoelastic drive and effectively inhibiting the vibration of the SEA.

"Design and biological Analysis of Supernuclear magnetic Limbs [ C ]// ASME 2012," Dynamic Systems and Control Conference Joint with the Jsme 2012, "by Clark Davenport et al, achieves both elasticity and damping by cascading column polyurethane between the motor and the load, and successfully achieves good human-computer interaction effects on exoskeleton robots, and is referred to as Series visco-elastic Actuators (SVA).

The above-described actuator either lacks a damping response or is large in volume and mass, making it difficult to achieve a compact application.

The present invention therefore seeks to provide a drive arrangement which is compact and which achieves a bi-directional flexible response similar to a biological motion system, whilst ensuring accuracy.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, the present invention provides a compact drive device that achieves a bi-directional flexible response similar to a biological motion system while ensuring accuracy.

In order to achieve the purpose, the invention provides a series viscoelastic driver based on a bionic tendon, which comprises a driving steering engine, the bionic tendon, a rotary joint and a base. The driving steering engine and the rotating joint are fixedly installed on the base, and the driving steering engine is connected with the rotating joint through the bionic tendon.

Further, the drive steering engine still includes the steering engine mounting, the drive steering engine passes through the steering engine mounting is installed on the base.

Furthermore, the steering engine fixing part is fixedly connected with the base through bolts.

Further, the bionic tendon is a viscoelastic polymer material.

Further, the number of the bionic tendons is 2.

Furthermore, the rotary joint further comprises a joint fixing piece and a joint rotating piece, the rotary joint is fixedly installed on the base through the joint fixing piece, and the joint rotating piece is installed on the joint fixing piece.

Further, the joint rotating piece and the joint fixing piece are arranged to be rotatable relative to each other.

Further, the rotary joint further comprises an electromagnetic rotary encoder, an encoder support and a magnet support, wherein the electromagnetic rotary encoder and the encoder support are installed on the joint fixing piece, and the magnet support is installed on the joint rotating piece.

Further, the electromagnetic rotary encoder further includes a magnet disposed in the magnet holder.

Further, the magnet support is fixedly installed on the joint rotating member through a bolt.

The series viscoelastic driver based on the bionic tendon provided by the invention realizes flexible rotary motion in a compact form, realizes bidirectional flexible response similar to a biological motion system under the condition of ensuring precision, and can be used as a driving device of a bionic robot, an industrial manipulator and the like.

The conception, specific composition and technical effects of the present invention will be further described in conjunction with the accompanying drawings to fully understand the objects, features and effects of the present invention.

Drawings

FIG. 1 is a three-dimensional view of a preferred embodiment of the present invention;

FIG. 2 is a three-dimensional exploded view of a preferred embodiment of the present invention;

FIG. 3 is a schematic transmission diagram of a preferred embodiment of the present invention.

Description of the reference numerals

1-servo steering engine, 101-steering engine fixing piece, 102-first tendon fixing piece, 103-second tendon fixing piece, 2-bionic tendon, 3-rotary joint, 301-joint fixing piece, 302-joint rotating piece, 303-electromagnetic rotary encoder, 304-encoder support, 305-magnet support and 4-base.

Detailed Description

The following examples are provided to further illustrate the present invention, and the examples are implemented on the premise of the technical solution of the present invention, and the embodiments and the operation procedures are given, but the scope of the present invention is not limited to the following examples.

As shown in fig. 1, in a preferred embodiment of the present invention, a series viscoelastic actuator based on a bionic tendon is provided, which includes a driving steering engine 1, a bionic tendon 2, a rotary joint 3 and a base 4. The driving steering engine 1 and the rotating joint 3 are fixedly installed on the base 4, and the driving steering engine 1 is connected with the rotating joint 3 in series through the bionic tendon 2. The base 4 is a columnar member with a rectangular cross section, grooves are formed in four sides of the columnar member, and the distances between the grooves formed in the columnar member are equal.

As shown in fig. 2, the driving steering engine 1 is fixedly mounted on the base 4 through a steering engine fixing member 101. Steering wheel mounting 101 adopts bolt mode and base 4 fixed connection. The driving steering engine 1 is a servo steering engine. The first tendon fixing part 102 is a pair of sheet members with grooves at two ends, and the pair of sheet members are fixed on two sides of the driving steering engine 1 through bearings and bolts respectively. The number of the bolts can be set randomly according to needs, and preferably, the number of the bolts is 4.

The revolute joint 3 comprises a non-revolute part, a revolute part and a rotary coding device. The non-rotating part is used as a fixed supporting base of the rotating joint 3, is fixed on the base 4 and keeps a fixed distance with the driving steering engine 1. The fixed distance can be adjusted as desired, and preferably, the fixed distance is set to be the length of the human tendon, for example, 15 cm. In the present embodiment, a structural form of the rotational joint 3 is provided, and as shown in fig. 2, the non-rotational part is a U-shaped joint fixing member 301. The rotating part is used as a movable supporting base of the rotating joint 3 and is connected with the non-rotating part, and the rotating part and the non-rotating part can freely rotate relative to each other. In this embodiment, a form of turning part structure is provided, such as a U-shaped joint rotating member 302 shown in fig. 2. The joint rotating member 302 is connected to the joint fixing member 301 through a bearing and a bolt, and the joint rotating member and the joint fixing member can freely rotate relative to each other.

The rotary encoder device includes an electromagnetic rotary encoder 303, an encoder support 304, and a magnet support 305. The magnet holder 305 is a cylindrical structure, which is fixed to the joint rotary 302 by a bolt, and the magnet holder 305 embeds the magnet of the electromagnetic rotary encoder 303. The encoder mount 304 fixes the electromagnetic rotary encoder 303 on the other side of the joint fixture 301. When the rotary joint 3 rotates, the magnet embedded in the magnet holder 305 and the electromagnetic rotary encoder 303 rotate relative to each other. The second tendon fixing members 103 are disposed on two outermost sides of the rotary joint 3, the second tendon fixing members 103 are a pair of sheet structures with grooves at two ends, and preferably, the second tendon fixing members 103 are the same as the first tendon fixing members 102. The pair of plate-like structures of the second tendon fixing member 103 is fixed to the joint rotating member 302 by a bearing and a bolt. The grooves of the first tendon fixing part 102 and the second tendon fixing part 103 are arranged in a back-to-back direction, and the relative heights between the grooves can be arbitrarily set, and preferably, the relative heights of the grooves are the same.

The bionic tendon 2 is composed of a pair of viscoelastic elements made of viscoelastic polymer materials, and has a flexible adaptation effect in a dynamic deformation process. A viscoelastic element of the bionic tendon 2 is arranged in the upper end grooves of the first tendon fixing part 102 and the second tendon fixing part 103, and the other elastic element is arranged in the lower end grooves of the first tendon fixing part 102 and the second tendon fixing part 103, so that the driving steering engine 1 and the rotating joint 3 are combined in series. The flexible torque transmission is realized between the rotary joint 3 and the driving steering engine 1 through the bionic tendon 2, and then the control effect of the motion and the strength of the bionic flexible joint is realized. The bionic tendon 2 is used in pairs, and produces similar muscle antagonism effect in the process of transmitting torque. The bionic tendon 2 forms pretightening force through pretensioning, and avoids force and movement mutation caused by relaxation generated in movement.

As shown in fig. 3, when the rotation angles of the driving steering engine 1 and the rotating joint 3 are inconsistent, the lengths of the bionic tendons 2 are inconsistent, and a rotating torque is generated, and by using the mechanism, the driver can stably output the torque.

By using the rotary encoder in the rotary joint 3, the absolute angle of the rotary joint 3 can be controlled, and the driver can stably output the rotation angle.

The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.

Claims

1. A series viscoelastic driver based on a bionic tendon is characterized by comprising a driving steering engine, the bionic tendon, a rotary joint and a base, wherein the driving steering engine and the rotary joint are fixedly arranged on the base, and the driving steering engine is connected with the rotary joint through the bionic tendon; the rotary joint further comprises a joint fixing piece and a joint rotating piece, the rotary joint is fixedly arranged on the base through the joint fixing piece, and the joint rotating piece is arranged on the joint fixing piece;

the joint rotating piece and the joint fixing piece are arranged to rotate relatively;

the rotary joint further comprises an electromagnetic rotary encoder, an encoder support and a magnet support, the electromagnetic rotary encoder and the encoder support are installed on the joint fixing piece, and the magnet support is installed on the joint rotating piece.

2. The bionic tendon-based series viscoelastic actuator as claimed in claim 1, wherein the driving steering engine further comprises a steering engine fixing member, and the driving steering engine is mounted on the base through the steering engine fixing member.

3. The bionic tendon-based series viscoelastic actuator as claimed in claim 2, wherein the steering engine fixing member is fixedly connected with the base by bolts.

4. The biomimetic tendon based in-line viscoelastic actuator of claim 1, wherein the biomimetic tendon is a viscoelastic polymer material.

5. The biomimetic tendon based in-line viscoelastic actuator of claim 1, wherein the number of the biomimetic tendons is 2.

6. The biomimetic tendon based in-line visco-elastic actuator of claim 1, wherein the electromagnetic rotary encoder further comprises a magnet disposed in the magnet mount.

7. A biomimetic tendon based in-line viscoelastic actuator as claimed in claim 1, wherein the magnet mount is fixedly mounted on the joint rotator by a bolt.