CN108742957B

CN108742957B - Multi-sensor fusion artificial limb control method

Info

Publication number: CN108742957B
Application number: CN201810651722.1A
Authority: CN
Inventors: 盛鑫军; 吕博; 朱向阳
Original assignee: Shanghai Jiaotong University
Current assignee: Shanghai Jiaotong University
Priority date: 2018-06-22
Filing date: 2018-06-22
Publication date: 2021-02-09
Anticipated expiration: 2038-06-22
Also published as: CN108742957A

Abstract

The invention discloses a multi-sensing fusion artificial limb control method, which relates to the technical field of artificial limbs and comprises the following steps: the first sensor collects myoelectric signals of forearm muscles of an amputation patient during autonomous contraction; the first sensor detects the information of the second sensor and judges the wrist direction of the artificial hand of the amputee; after the wrist of the artificial hand is adjusted to a posture suitable for grabbing, triggering a camera device through muscle contraction, and shooting a grabbed object by the camera device; the third sensor determines the grabbing mode of the artificial hand according to the grabbed object shot by the camera device, and controls the grabbing force of the artificial hand for grabbing the object according to the muscle contraction ratio of the amputee; the amputee can release the grasped object by muscle contraction. The method can enable the amputee to independently control the artificial limb hand, the operation is more natural, the training process is not needed, the experience is more friendly, and the use is more convenient.

Description

Multi-sensor fusion artificial limb control method

Technical Field

The invention relates to the technical field of artificial limbs, in particular to a multi-sensing fusion artificial limb control method.

Background

According to the sixth national population census total population in China, the second national disabled person sampling survey of the proportion of the national disabled persons to the national total population and the proportion of various disabled persons to the total number of the disabled persons, the total number of the national disabled persons at the end of 2010 is calculated to be 8502 thousands of persons, wherein 2472 thousands of persons are physically disabled. Compared with 2412 thousands of estimated body disability population in 2006, 60 thousands of body disability population are newly added. For the disabled people, the functional prosthesis is worn, and the movement ability and the confidence of the disabled people in daily life and work are reshaped, so that the functional prosthesis has important social significance.

At present, the main control modes of commercial artificial limbs at home and abroad can be divided into: mechanical cable-controlled artificial limbs, myoelectric artificial limbs and myoelectric cable-controlled hybrid artificial limbs. The mechanical cable-controlled artificial limb has limitations in controlling multi-finger dexterous artificial limbs due to inherent defects of single function, inconvenient operation and the like. The differentiated muscle electrical signals generated by recording different contraction states of the stump of the amputee are used as a control source and widely used for controlling the artificial upper limb prosthesis. The current upper limb prosthesis controls multiple degrees of freedom by using two electromyographic signals of a pair of antagonistic muscles, such as: one mode of muscle contraction intensity being greater than the other mode of muscle contraction intensity, the other mode of simultaneous contraction of a pair of antagonistic muscles, etc. increases the burden on amputees. According to statistics, the abandon rate of the artificial limb adopting the myoelectricity control mode at present reaches more than 50%. CN101987048B proposes a prosthesis control system based on a pattern recognition method. The basic assumption of the pattern recognition method is that the electromyographic signals of the same action for a plurality of times or a plurality of days have similarity, however, the electromyographic signals are random signals and are easily influenced by sweating, electrode position change and the like, so that the early training model adopting the pattern recognition mode is invalid, an amputee needs to be continuously retrained, and the training burden of the amputee is increased.

The technical problem to be solved by the invention is how to provide a control method of an artificial limb, so that the artificial limb is simple and easy to use and flexible control with multiple degrees of freedom is realized.

Therefore, those skilled in the art are dedicated to develop a multi-sensor fusion prosthesis control method, which enables an amputee to autonomously control a prosthetic hand, is more natural to operate, adopts visual assistance to determine a grabbing mode, does not need a training process, is more friendly in experience, and is more convenient to use.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, the technical problem to be solved by the present invention is how to make the control of the prosthesis simple and easy to use, and to achieve dexterous control with multiple degrees of freedom.

In order to achieve the above object, the present invention provides a multi-sensing fusion prosthesis control method, which comprises the following steps: the first sensor collects myoelectric signals of forearm muscles of an amputation patient during autonomous contraction; the first sensor detects the information of the second sensor and judges the wrist direction of the artificial hand of the amputee; after the wrist of the artificial hand is adjusted to a posture suitable for grabbing, triggering a camera device through muscle contraction, and shooting a grabbed object by the camera device; the third sensor determines the grabbing mode of the artificial hand according to the grabbed object shot by the camera device, and controls the grabbing force of the artificial hand for grabbing the object according to the muscle contraction ratio of the amputee; the amputee can release the grasped object by muscle contraction.

Further, the camera device is arranged on the palm part of the artificial hand.

Further, the first sensor is a single channel electromyography sensor.

Further, the single-channel electromyography sensor comprises a differential electrode, a filter circuit and an amplifying circuit.

Further, the single-channel electromyography sensor is arranged inside the accepting cavity of the prosthetic hand.

Further, the second sensor is a multi-axis motion sensor.

Further, the multi-axis motion sensor includes a three-axis accelerometer, a three-axis angular velocity meter, and a three-axis magnetometer.

Further, the multi-axis motion sensor is disposed inside an socket of the prosthetic hand.

Further, the third sensor is a vision sensor.

Further, the vision sensor is a two-dimensional digital camera.

The method can enable the amputee to autonomously control the artificial limb hand, the operation is more natural, the grabbing mode is determined by adopting visual assistance, the training process is not needed, the experience is more friendly, and the use is more convenient.

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

Drawings

FIG. 1 is a schematic diagram of a multi-sensory fusion prosthesis control method in accordance with a preferred embodiment of the present invention;

fig. 2 is a flow chart of a multi-sensing fusion prosthesis control method of the present invention.

Detailed Description

The technical contents of the preferred embodiments of the present invention will be more clearly and easily understood by referring to the drawings attached to the specification. The present invention may be embodied in many different forms of embodiments and the scope of the invention is not limited to the embodiments set forth herein.

In the drawings, structurally identical elements are represented by like reference numerals, and structurally or functionally similar elements are represented by like reference numerals throughout the several views. The size and thickness of each component shown in the drawings are arbitrarily illustrated, and the present invention is not limited to the size and thickness of each component. The thickness of the components may be exaggerated where appropriate in the figures to improve clarity.

As shown in fig. 1, the multi-sensing fusion prosthesis control method includes a multi-finger dexterous prosthetic hand 101, a single-degree-of-freedom prosthetic wrist portion 102, a prosthetic socket 103, a single-channel differential electrode and multi-axis motion sensor integrated module 104 arranged in the socket, a camera 105 arranged at the root of a palm, and an object to be grabbed 106.

When the amputee is used, the artificial limb socket 103 is worn on the forearm stump, and the single-channel differential electrode and multi-axis motion sensor integrated module 104 is placed on any muscle surface which has obvious contraction in the motion process, so that good contact between the myoelectric electrode and the skin surface is ensured.

As shown in fig. 2, after the amputee wears the prosthetic hand, the physical switch of the prosthetic hand is started, and the power supply of the prosthetic hand is connected with the reset 201 to reset to the natural state. When the amputee wants to grasp an object, the upper arm brings the prosthetic hand to the object to be grasped 202.

The amputee determines if the wrist of the prosthetic hand is adjusted to the proper position 203. If the wrist of the artificial limb hand does not conform to the expected grabbing position, the forearm muscle of the amputee contracts for a short time, and the arm stump 204 is slightly rotated, and meanwhile, whether the single-channel electromyographic signal exceeds the threshold value 205 or not and whether the acceleration signal exceeds the threshold value 206 or not are judged, if any of the single-channel electromyographic signal and the acceleration signal does not exceed the threshold value, the wrist of the artificial limb hand does not perform any action, and the amputee needs to perform muscle contraction for a short time again and rotate the arm 204; if both exceed the threshold, the wrist will rotate 90 degrees 207.

The wrist of the prosthetic hand is preset with three states: a natural palm-centered state, a palm-up state rotated 90 degrees to the outside of the human body, and a palm-down state rotated 90 degrees to the inside of the human body. The rotation direction of the artificial hand wrist can be determined by slightly rotating the direction of the forearm stump of the amputee, and meanwhile, the posture of the artificial hand can be adjusted by rotating the forearm stump, and the receiving cavity drives the artificial hand to further finely adjust.

After the wrist of the prosthetic hand is adjusted to the proper position 203, the amputee takes a picture of the object to be grasped 208 by a short contraction of the muscles. The grip mode (grip, pinch, etc.) is determined using machine vision methods 209. The fingers of the prosthetic hand are rotated through a small angle to perform a pre-grabbing action, and the amputee confirms whether the grabbing mode is the expected grabbing mode. If yes, the muscle contracts, the grabbing force is controlled proportionally 210, and grabbing 211 is completed; if not, the amputee may briefly contract the muscles to photograph the object to be grasped 208 to achieve the desired grasping pattern.

After the amputee finishes grabbing, the amputee can contract for a long time through muscles 212, and after the single-channel electromyographic signal exceeds a threshold value 213, the prosthetic hand releases the grabbed object 214. Meanwhile, the artificial limb wrist still keeps the current state and waits for the next grabbing, so that the artificial limb control under the participation of the amputee patient is realized.

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 multi-sensing fusion prosthesis control method is characterized by comprising the following steps:

the first sensor collects myoelectric signals when muscles of the forearm of an amputation patient contract autonomously, the second sensor collects acceleration signals, the amputation patient judges whether the wrist of the artificial hand is adjusted to a proper position, if the wrist of the artificial hand does not accord with an expected grabbing position, the muscles of the forearm of the amputation patient contract for a short time, the arm stump is rotated, meanwhile, whether single-channel myoelectric signals exceed a threshold value or not and whether the acceleration signals exceed the threshold value or not are judged, if any one of the single-channel myoelectric signals does not exceed the threshold value, the wrist of the artificial hand does not execute any action, and the amputation patient needs to perform muscle contraction for a short time again and rotate the arm; if both exceed the threshold, the wrist will rotate 90 degrees;

after the wrist of the artificial hand is adjusted to a posture suitable for grabbing, triggering a camera device through short-time muscle contraction, wherein the camera device shoots an object to be grabbed;

determining the grabbing mode of the artificial hand by adopting a machine vision method according to the object to be grabbed shot by the third sensor;

the amputee controls the gripping force of the artificial hand for gripping the object in proportion through muscle contraction to realize the gripping of the object;

the amputation patient contracts for a long time through muscles, and releases the grabbed object when the electromyographic signal exceeds a threshold value;

wherein the third sensor is a vision sensor that is a two-dimensional digital camera.

2. A multi-sensory fusion prosthetic control method of claim 1, wherein the imaging device is disposed at a palm portion of the prosthetic hand.

3. A multi-sensory fusion prosthetic control method of claim 1, wherein the first sensor is a single channel electromyography sensor.

4. A multi-sensory fused prosthetic control method according to claim 3, wherein the single channel electromyography sensor comprises a differential electrode, a filter circuit, and an amplification circuit.

5. A multi-sensory fusion prosthetic control method according to claim 3, wherein the single channel electromyographic sensor is disposed inside an socket of the prosthetic hand.

6. A multi-sensory, fused prosthetic control method according to claim 1, wherein the second sensor is a multi-axis motion sensor.

7. A multi-sensory, fused prosthetic control method according to claim 6, wherein the multi-axis motion sensors include a three-axis accelerometer, a three-axis angular velocity meter, and a three-axis magnetometer.

8. A multi-sensory fused prosthetic control method according to claim 6, wherein the multi-axis motion sensor is disposed inside an socket of the prosthetic hand.