CN103690333A - Variable rigidity knee joint rehabilitation training device with biological force feedback and method of device - Google Patents

Abstract

The invention discloses a variable rigidity knee joint rehabilitation training device with biological force feedback and a method of the device. The device comprises a force application structure, a bracket structure, a biological force signal detection unit and a control unit, wherein the biological force signal detection unit comprises a surface electrode plate, a signal conditioner, a data acquisition and control system, a travel switch for indicating positions and an angle sensor, the travel switch comprises a magnetic switch and a proximity switch, and the control unit comprises a computer, a proportional flow valve, a proportional pressure valve, a switch valve, an electromagnetic directional valve and a programmable controller. The rehabilitation degree of a diseased knee joint can be accurately mastered, driving force/damping force and training angles and angular speeds in a rehabilitation training scheme are determined according to the rehabilitation degree, and the device is fine in scientificity and overcomes the shortcoming that a rehabilitation scheme is made completely by the aid of personal experience of medical workers in the past.

Description

A kind of stiffness variable knee-joint rehabilitation training device and method thereof with Biological Strength feedback

Technical field

The invention belongs to and can be applicable to carry out rehabilitation training technology after knee joint injury corrective surgery, particularly a kind of stiffness variable knee-joint rehabilitation training device and method thereof with Biological Strength feedback.

Background technology

Knee joint is in human body, to bear the important joint of supporting and motor function.If can not effectively be taken exercise in time in the convalescence of knee joint after there is damage or medical operating, very easily cause adhesion and the amyotrophy of knee joint position, thereby greatly limit kneed motor capacity, serious even can cause the forever damaged of joint component function.Therefore, modern rehabilitation medicine thinks, postoperatively in time knee joint carried out to appropriateness, effective reconditioning, to recovering knee joint function, has very important effect.

The basic demand of knee joint recovery apparatus is mainly concentrated on to two aspects: safety and effectiveness.Safety refers to that rehabilitation appliances are when carrying out rehabilitation training to trouble knee joint, can not produce secondary injury to suffering from knee joint; Effectiveness refers to that rehabilitation appliances not only will have the exercise to joint mobility, and will have the associated muscle in joint and ligament are carried out to necessary stretching and the function of Myodynamia recovery.Therefore knee joint rehabilitation device should meet simultaneously compliance good, passive-functional requirement that active training combines.

At present, training device for knee joint rehabilitation on sale on market (is commonly referred to as CPM machine, Continuous Passive Motion) be all substantially the rigid structure drive form that adopts motor+mechanical transmission mechanism, by driven by motor mechanical transmission mechanism, moved, thereby drive limbs of patient motion (US Patent No. 6325770B1 and US6221033B1, Chinese patent 200410006254.0 etc.), this type of drive often cannot apply driving force neatly according to the different rehabilitation stage of suffering from knee joint, or the angle of change rehabilitation training, therefore very easily knee joint is caused to secondary injury.Although there are many scholars this to be carried out improve (Chinese patent 200910031938.9), also increased the link of some Based Intelligent Control, the drawback of the poor stability that rigidity type of drive causes is not fundamentally eradicated.Chinese patent 200410077721.9 utilizes this soft drive element of Mckibben type Pneumatic artificial muscle as the driving element of knee joint rehabilitation device, has greatly improved the training of safety of device for rehabilitation.But this device for rehabilitation can only be implemented passive exercise to patient, cannot meet the requirement of active training.Meanwhile, because the effective travel of Mckibben type pneumatic muscles is shorter, the training angle that this device for healing and training can be provided is less, cannot realize the wide-angle motion in knee-joint rehabilitation training.

For these above-mentioned problems, early stage, we proposed a kind of knee-joint active-passive rehabilitation training device (patent No.: 201010146310.6) of bidirectional flexible, utilized the soft drive scheme of the large stroke pneumatic flexible actuator of Rodless cylinder+thrust, at the end that drives stroke, resist a pair of Pneumatic flexible actuator has been installed, utilize guarantee to go down on one's knees-the to stretch safety of knee-joint rehabilitation training of knee joint both direction of the compliance of this driver, simultaneously, by the confession/aerofluxus of the different air cavitys of control cylinder and different Pneumatic flexible actuators, for suffering from knee joint, in different rehabilitation processes, provide passive exercise, the multiple different training method such as active training.But this device for rehabilitation of development in early stage, although can realize corresponding rehabilitation training, training power and training angle in the different training stages after training are given according to doctor's personal experience, have affected to a certain extent the effect of rehabilitation training.

In order more scientifically to carry out rehabilitation training to suffering from knee joint, need a kind of can to different rehabilitation objects or the actual rehabilitation state science of carrying out in different rehabilitation stages of same target evaluate objectively and take this as a foundation formulate scientific and effective rehabilitation scheme, to reaching the rehabilitation appliances of optimal rehabilitation effect.According to this thinking, early stage, we carried out relevant theoretical research work (Institutes Of Technology Of Nanjing's Master's thesis: the knee joint recovery Robot Control Technology research based on surface electromyogram signal, author: Wang Shiyun) to detection, processing, assessment and the control method etc. of the Biological Strength signal of the associated muscle of knee joint.But how by correlation technique, to realize and these researchs are also failed to solve these technical problems for rehabilitation training at current disclosed document.

Summary of the invention

The object of the present invention is to provide a kind of stiffness variable knee-joint rehabilitation training device and method thereof with Biological Strength feedback, applicable to carrying out rehabilitation training after knee joint injury operation in patients, can detect in real time and suffer from the knee joint muscle Biological Strength signal that the associated muscle of knee joint produces while going down on one's knees firmly in during rehabilitation training, and this signal is fed back, the change rigidity control method of the damping force when determining driving force when passive exercise or active training, thereby realize the Based Intelligent Control to knee-joint rehabilitation training, to reaching best rehabilitation training effect.

The technical solution that realizes the object of the invention is:

A kind of stiffness variable knee-joint rehabilitation training device with Biological Strength feedback, comprise force application structure, carrier structure, force application structure comprises Rodless cylinder, the first Pneumatic flexible actuator, the second Pneumatic flexible actuator, sliding pair, and sliding pair is comprised of rod member and slide block; Carrier structure comprises thigh bar, shank bar, between shank bar and thigh bar, forms revolute pair; Also comprise Biological Strength detecting signal unit, control unit, wherein Biological Strength detecting signal unit comprises travel switch, the angular transducer of surface electrical pole piece, signal conditioner, data collection and control system, position indication use, the trip switch is comprised of magnetic switch and approach switch, and control unit comprises computer, proportional flow control valve, proportional pressure valve, switch valve, solenoid directional control valve, Programmable Logic Controller;

The first described Pneumatic flexible actuator, the second Pneumatic flexible actuator respectively connect a proportional flow control valve, two QI KOU of Rodless cylinder connect respectively a proportional flow control valve, each proportional flow control valve connects a proportional pressure valve, each proportional pressure valve connects a switch valve, each switch valve is all connected with solenoid directional control valve, and proportional flow control valve, proportional pressure valve, switch valve and solenoid directional control valve are communicated with by trachea;

Surface electrical pole piece is connected by data wire with signal conditioner, Programmable Logic Controller is connected by data wire with computer, magnetic switch, approach switch, angular transducer, switch valve, solenoid directional control valve respectively, and data collection and control system is connected by data wire with computer, signal conditioner, proportional pressure valve, proportional flow control valve respectively; Plural magnetic switch is installed in the groove of outer surface of cylinder block of Rodless cylinder, and the position that magnetic switch is placed can be adjustable in the travel range of cylinder along Rodless cylinder axis direction, the travel position of the piston of Rodless cylinder during for detection of rehabilitation training; Rod member both sides at sliding pair arrange approach switch, angular transducer be arranged on thigh bar and and shank bar between rotation vice division chief, and concentric with this revolute pair.

A kind of stiffness variable knee-joint rehabilitation training method with Biological Strength feedback, on the knee-joint active-passive rehabilitation training device of bidirectional flexible, carry out, surface electrical pole piece is affixed on to the corresponding muscle of the lower limb of undergoing training place when carrying out rehabilitation training, with the Biological Strength producing due to muscle contraction in test during rehabilitation training, this Biological Strength signal sends by data line amplification and the Filtering Processing that signal conditioner carries out signal to, and the signal after being processed by data collection and control system acquisition, signal after data collection and control system is processed signal conditioner carries out sending computer to after mould/number conversion, computer carries out eigenvalue RMS extraction to Biological Strength signal, the assessment and analysis of signal power, the control instruction that data collection and control system is assigned computer carries out sending to proportional flow control valve and proportional pressure valve after D/A switch, the extent of opening of the control instruction control valve that proportional flow control valve and proportional pressure valve provide according to computer, to control the size of gas supply flow and supply gas pressure, break-make situation by Controlled by Programmable Controller switch valve and solenoid directional control valve respective electrical Magnet is carried out the switching of control valve, thereby controls the break-make of corresponding pneumatic branch, to control the process of rehabilitation training.

The present invention compared with prior art, its remarkable advantage: (1) is by suffering from the real-time detection of the Biological Strength signal of the associated muscle of knee joint in training process, can hold exactly and suffer from kneed rehabilitation degree, and take this as a foundation and determine driving force/damping force in rehabilitation training scheme and angle and the angular velocity of training, there is good science, avoided the personal experience who relies on medical personnel completely in the past to formulate the drawback of rehabilitation scheme.(2) by the effective control to supply gas pressure, can realize the rigidity of the Pneumatic flexible actuator of end is carried out to incremental control, with meet the passive exercise initial stage require that device for rehabilitation compliance is good, rigidity is low, to avoid causing secondary injury to suffering from knee joint, and the requirement its compliance constantly being weakened along with the propelling of rehabilitation process, be to require compliance good at the passive exercise initial stage, along with the propelling of rehabilitation process, the requirement of compliance is constantly weakened.(3), according to the recovery extent of muscular strength, by controlling extraction flow, can realize easily the control to damping force in active training process, to reach best rehabilitation training effect.

Below in conjunction with accompanying drawing, the present invention is described in further detail.

Accompanying drawing explanation

Fig. 1 is the frame for movement schematic diagram of the stiffness variable knee-joint rehabilitation training device of band Biological Strength feedback of the present invention.

Fig. 2 is that E of the present invention is to local enlarged diagram.

Fig. 3 is the composition schematic diagram of control system of the present invention.

Fig. 4 is the schematic flow sheet while utilizing the present invention to carry out rehabilitation training.

Fig. 5 is that Pneumatic flexible actuator dynamic stiffness is with the change curve of supply gas pressure.

Fig. 6 is the cross section geometric schematic diagram of the every one deck of Pneumatic flexible actuator spiral elastic pipes.

The specific embodiment

In conjunction with Fig. 1, Fig. 2 and Fig. 3, the stiffness variable knee-joint rehabilitation training device of band Biological Strength feedback of the present invention, comprises force application structure, carrier structure, Biological Strength detecting signal unit, control unit.Wherein force application structure comprises that the spiral elastic pipes 33 that base plate 1, Rodless cylinder 2, slide unit 3, the first Pneumatic flexible actuator 4(are flat by initial cross-section forms), guide rod 5, the second Pneumatic flexible actuator 6(be flat by initial cross-section spiral elastic pipes 33 forms), fixed support 7, connector 8, movable supporting frame 9, sliding pair 10; Carrier structure comprises thigh bar 11, thigh support plate 12, shank bar 13, shank support plate 14, foot bracket 15, coupling bar 16, T-shaped connector 17, L-type bar 18, the first adjusting device 19 and the second adjusting device 20; Biological Strength detecting signal unit comprises that surface electrical pole piece 21(number chooses as required), travel switch (comprise magnetic switch 25 and approach switch 26, number is chosen as required), the angular transducer 27 of signal conditioner 22, data collection and control system 23, position probing and indication use.Control unit comprises computer 24, proportional flow control valve 28, proportional pressure valve 29, switch valve 30, solenoid directional control valve 31, Programmable Logic Controller 32.

Rodless cylinder 2 is fixed on base plate 1, place, both sides of the edge along Rodless cylinder 2 stroke directions on slide unit 3 is symmetrically installed with two fixed supports 7, between two fixed supports 7, along cylinder stroke direction, guide rod 5 is installed, the axis of this guide rod 5 is parallel with the axis of Rodless cylinder 2 pistons, left from L(on guide rod 5) right to R() direction is provided with the second Pneumatic flexible actuator 6 successively, movable supporting frame 9 and the first Pneumatic flexible actuator 4, two pairs of sliding pair 10 symmetries are placed on slide unit 3 along the both sides of the centrage of Rodless cylinder 2 stroke directions, and the glide direction of sliding pair 10 is parallel with the stroke directions of Rodless cylinder 2 pistons, sliding pair 10 is comprised of rod member and slide block, and wherein, the two ends of rod member are separately fixed on two fixed supports 7, and slide block is fixed on movable supporting frame 9.Movable supporting frame 9 is fixedly connected with respectively T-shaped connector 17 in the both sides of the direction vertical with cylinder stroke direction, on two T-shaped connectors 17, be connected with separately shank bar 13, between two shank bars 13, be connected with coupling bar 16, foot bracket 15 is installed on coupling bar 16, between two shank bars 13 and coupling bar 16, be provided with the shank support plate 14 that is provided with material softness between 19, two shank bars 13 of rod member length adjustment device.Between movable supporting frame 9 and T-shaped connector 17, between shank bar 13 and thigh bar 11 and form revolute pair between thigh bar 11 and L-type bar 18.12, two the L-type bars 18 of thigh support plate that are provided with material softness between two thigh bars 11 are separately fixed at the both sides of base plate 1, and are provided with rod member length adjustment device 20.

Described the first Pneumatic flexible actuator (4), the second Pneumatic flexible actuator (6) respectively connect a proportional flow control valve, two QI KOU of Rodless cylinder (2) connect respectively a proportional flow control valve, each proportional flow control valve (four) connects a proportional pressure valve, each proportional pressure valve (four) connects a switch valve, each switch valve (four) is all connected with solenoid directional control valve (31), and proportional flow control valve (28), proportional pressure valve (29), switch valve (30) and solenoid directional control valve (31) are communicated with by trachea; Form altogether 4 pneumatic branch, by compressed air source unit, supply with compressed air.Wherein two pneumatic branch are connected with two QI KOU of Rodless cylinder 2, and two other pneumatic branch connects respectively the first Pneumatic flexible actuator 4 and the second Pneumatic flexible actuator 6.

Surface electrical pole piece (21) is connected by data wire with signal conditioner (22), Programmable Logic Controller (32) is connected by data wire with computer (24), magnetic switch (25), approach switch (26), angular transducer (27), switch valve (30), solenoid directional control valve (31) respectively, and data collection and control system (23) is connected by data wire with computer (24), signal conditioner (22), proportional pressure valve (29), proportional flow control valve (28) respectively; The magnetic switch (25) of two above (number is determined as required) is installed in the groove of outer surface of cylinder block of Rodless cylinder (2), the position that magnetic switch (25) is placed can be adjustable in the travel range of cylinder along Rodless cylinder (2) axis direction, the travel position of the piston of Rodless cylinder during for detection of rehabilitation training (2); In the rod member both sides of sliding pair (10), approach switch (26) is set, angular transducer (27) be arranged on thigh bar (11) and and shank bar (13) between rotation vice division chief, and concentric with this revolute pair.

In conjunction with Fig. 4, the stiffness variable knee-joint rehabilitation training method of band Biological Strength feedback of the present invention, on the knee-joint active-passive rehabilitation training device of above-mentioned bidirectional flexible, carry out, surface electrical pole piece (21) is affixed on to the corresponding muscle of the lower limb of undergoing training place when carrying out rehabilitation training, with the Biological Strength producing due to muscle contraction in test during rehabilitation training, this Biological Strength signal sends by data line amplification and the Filtering Processing that signal conditioner (22) carries out signal to, and by the signal after data collection and control system (23) acquisition process, signal after data collection and control system (23) is processed signal conditioner (22) carries out sending computer (24) to after mould/number conversion, computer (24) extracts (the root-mean-square value RMS that for example extracts signal) to the eigenvalue of Biological Strength signal, the assessment and analysis of signal power, the control instruction that data collection and control system (23) is assigned computer (24) (for example: judge whether RMS value surpasses the threshold value setting, if RMS value is less than the threshold value setting, maintain last control signal constant, otherwise, if RMS value is greater than the threshold value setting, increase corresponding control signal magnitude of voltage) carry out D/A switch and (about data collection and control system 23, realize mould/number, D/A switch function can adopt collection and the Control card of Yan Hua company) after send to proportional flow control valve (28) and proportional pressure valve (29), the extent of opening of the control instruction control valve that proportional pressure valve (29) and proportional flow control valve (28) can send according to computer (24), to control supply gas pressure or gas supply flow.To solenoid directional control valve (31) and switch valve (30), break-make that can control valve electric magnet by Programmable Logic Controller (32) is carried out the switching of control valve, to control the break-make of corresponding pneumatic branch.

Below in conjunction with Fig. 1～6, specific embodiment of the invention process is described:

One, passive exercise

When suffering limb is carried out knee joint passive exercise at the initial stage of rehabilitation, first the Rodless cylinder in device for rehabilitation 2 and Pneumatic flexible actuator are placed in to initial position.The lower limb of needs training be placed on the carrier structure of the knee-joint rehabilitation training device that the present invention proposes and carry out necessary fixingly, one group of surface electrical pole piece 21 being affixed on respectively to each piece muscle place of thigh and Calf muscle group in lower limb.Open each power supply, source of the gas and computer control system.Given initial supply gas pressure and gas supply flow control signal.Simultaneously, control the electric magnet on solenoid directional control valve 31 left sides and the energising of the electric magnet of 2 switch valves 30 that are connected with Rodless cylinder 2, guarantee the P1 mouth air inlet of Rodless cylinder 2, P2 mouth aerofluxus (as shown in Figure 3), slide unit 3 on Rodless cylinder 2 is to the dextrad motion shown in Fig. 3, linkage by formations such as the thigh bar 11 in slide unit 3 drive carrier structures, shank bars 13 moves, the action thereby drive trouble knee joint is gone down on one's knees.The training of going down on one's knees; After magnetic switch 25 detects Rodless cylinder and moves right and put in place, the detection signal that will put in place sends to Programmable Logic Controller 32, Programmable Logic Controller 32 sends next control instruction, the electric magnet energising of the electric magnet power-off of 2 switch valves 30 that control is connected with Rodless cylinder 2,2 switch valves 30 that are connected with the second Pneumatic flexible actuator 6 with the first Pneumatic flexible actuator 4, guarantee the first Pneumatic flexible actuator 4 inflations, the second Pneumatic flexible actuator 6 aerofluxuss, slide unit 3 continues to have moved right the end stroke of going down on one's knees and training.When the slide block in sliding pair 10 touches the approach switch 26 that is arranged on sliding pair 10 rod member right-hand members, or the muscle Biological Strength signal collecting reached the upper threshold of prior setting, and the process of going down on one's knees finishes.24 detection signals of approach switch 26 or computer are to Programmable Logic Controller 32, Programmable Logic Controller 32 continues to send next control instruction, control the electric magnet power-off on solenoid directional control valve 31 left sides, the electric magnet "on" position of 2 switch valves 30 that the electric magnet on the right is switched on, is connected with the second Pneumatic flexible actuator 6 with the first Pneumatic flexible actuator 4 is constant, guarantee the second Pneumatic flexible actuator 6 inflations, the first Pneumatic flexible actuator 4 aerofluxuss, start to stretch knee joint action.When the slide block in sliding pair 10 touches the approach switch 26 that is arranged on sliding pair 10 rod member left ends, 26 detection signals of approach switch are to Programmable Logic Controller 32, Programmable Logic Controller 32 continues to send next control instruction, control the electric magnet power-off of 2 switch valves 30 that are connected with the second Pneumatic flexible actuator 6 with the first Pneumatic flexible actuator 4, the electric magnet energising of 2 switch valves 30 that are connected with Rodless cylinder 2, guarantee the P2 mouth air inlet of Rodless cylinder 2, the aerofluxus of P1 mouth, continued to stretch knee joint action, until detecting Rodless cylinder motion left, magnetic switch 25 puts in place, a training stroke finishes, and wait for that Programmable Logic Controller 32 sends the instruction of next training circulation.

The supply gas pressure being sent by computer 24 and gas supply flow control signal can be controlled at supply gas pressure and the flow of supplying with Rodless cylinder 2 or the first Pneumatic flexible actuator 4 in the training process of going down on one's knees, thereby control the size of driving force and speed.Go down on one's knees in process, each surface electrical pole piece 21 detects electromyographic signal, detection signal through signal conditioner 22 amplify, the processing such as filtering, by data collection and control system 23, gather and carry out sending computer 24 to after mould/number conversion, software processing system in computer carries out (for example: judge whether RMS value reaches 0.5) after the strong and weak analysis and evaluation of eigenvalue extraction, signal to the signal collecting, and assigns the control instruction of rehabilitation training next time.So circulate, can suffer from the passive rehabilitation training of knee joint.

Two, active training

First open each power supply and computer control system, Programmable Logic Controller 32 sends initial control instruction, control the electric magnet energising of electric magnet and all switch valve 30 on solenoid directional control valve 31 the right, guarantee state in inflation of the right chamber of the Rodless cylinder 2 in the present invention and the second Pneumatic flexible actuator 6, left chamber and state, the device for rehabilitation initial position in left end of the first Pneumatic flexible actuator 4 in aerofluxus of Rodless cylinder 2.The lower limb of needs training be placed on the carrier structure of the knee-joint rehabilitation training device that the present invention proposes and carry out necessary fixingly, one group of surface electrical pole piece 21 being affixed on respectively to each piece muscle place of thigh and Calf muscle group in lower limb.Given initial supply gas pressure and gas supply flow control signal.Then, Programmable Logic Controller 32 sends next control signal, controls the electric magnet power-off on solenoid directional control valve 31 the right, the energising of the electric magnet on the left side.Computer 24 sends control signal, to control the supply gas pressure of the proportional pressure valve 29 that is connected with the P1 mouth of Rodless cylinder 2 and is connected with Pneumatic flexible actuator 4, (this supply gas pressure is less, the positive force of suffering from knee joint during active training should be larger, this supply gas pressure of the final stage of rehabilitation training is 0) gas supply flow of the proportional flow control valve 28 that is connected and is connected with Pneumatic flexible actuator 4 with P1 mouth with Rodless cylinder 2 is (now, the valve port of proportional flow control valve 28 is placed in maximum), simultaneously, the control signal that computer 24 sends also will be controlled the size of extraction flow of the proportional flow control valve 28 that is connected with the P2 mouth of Rodless cylinder 2 and is connected with Pneumatic flexible actuator 6, and (this extraction flow is larger, the damping force that need overcome during active training is less, otherwise this extraction flow is less, the damping force that need overcome during active training is larger) the proportional pressure valve 29(that is connected and is connected with Pneumatic flexible actuator 6 with P2 mouth with Rodless cylinder 2 now, the valve port of proportional pressure valve 29 is placed in maximum).During the active training of suffering limb in carrying out rehabilitation process, initiatively firmly go to overcome the damping force that device for rehabilitation applies and complete the action of going down on one's knees, to reach the object to joint association muscular training.In active training process, each surface electrical pole piece 21 detects electromyographic signal, detection signal through signal conditioner 22 amplify, the processing such as filtering, by data collection and control system 23, gathered and carried out sending computer 24 to after mould/number conversion, the software processing system in computer carries out eigenvalue extraction to the signal collecting and carries out the analysis and evaluation of signal power.If the signal collecting has reached the upper threshold of prior setting, or magnetic switch 25 has detected the signal that puts in place, control solenoid directional control valve 31 the right electric magnet energisings, left side electric magnet power-off, guarantee the air inlet of P2 mouth, the aerofluxus of P1 mouth of Rodless cylinder 2, the second Pneumatic flexible actuator 6 air inlets, the first Pneumatic flexible actuator 4 aerofluxuss, complete and stretch knee joint action.Meanwhile, the control instruction of rehabilitation training is next time determined and assigned to computer 24, according to the size of the electromyographic signal detecting in last cycle of training.So circulation, can suffer from the initiative rehabilitation of knee joint and train.(list of references: Institutes Of Technology Of Nanjing's Master's thesis: the knee joint recovery Robot Control Technology research based on surface electromyogram signal, author: Wang Shiyun)

Three, Pneumatic flexible actuator becomes the control of rigidity

The present invention has adopted Pneumatic flexible actuator at the end of the stroke of going down on one's knees, and by controlling the supply gas pressure of Pneumatic flexible actuator, can change the rigidity of Pneumatic flexible actuator, while suffering from the different rehabilitation degree of knee joint to meet, device for rehabilitation is become the requirement of rigidity.Its method that becomes rigidity is: the dynamic stiffness K of Pneumatic flexible actuator _dfor quiet stiffness K _jwith air pressure stiffness K _qsum.

$\left\{\begin{array}{c}{K}_d=K_j+K_q\\ K_j=\frac{{\mathrm{<figure-callout\; id="2"\; label="K\; p"\; filenames="HDA0000445805710000011.png"\; state="\{\{state\}\}">K</figure-callout>}}_p^{}\mathrm{\&lambda;p}{\mathrm{\&pi;}}^2(\mathrm{\&pi;}-2)}{2N}H-K_p{\mathrm{\&lambda;p\&pi;}}^2[\mathrm{KR}(\mathrm{\&pi;}-1)+\frac{D}{2}]\\ K_q=p(H-H_{\max })[2a-\frac{{n(2\mathrm{aH}+b)}^2}{{\mathrm{aH}}^2+\mathrm{bH}+c}]\end{array}\right.$

Dynamic stiffness K is described below _dderivation.The following alphabetical physical quantity implication of first definition:

F is the power output of Pneumatic flexible actuator, p is supply gas pressure, H is the active length of Pneumatic flexible actuator, N is the number of plies of Pneumatic flexible actuator spiral elastic pipes, R is the outer ring radius of the spiral elastic pipes of Pneumatic flexible actuator while being expanded to circle, K is the radius changing rate of the spiral elastic pipes of Pneumatic flexible actuator, and D is guide rod diameter, r ₁for spiral elastic pipes annular contact surface internal diameter, r ₂for spiral elastic pipes annular contact surface external diameter, the actual outer ring radius of spiral elastic pipes when R' is Pneumatic flexible actuator work, h is the height of every helical layer elastic tube, l is radially contact length of adjacent spiral elastic pipes layer,

for the extended length correction coefficient of Pneumatic flexible actuator, H _maxfor the theoretical maximum elongation length of Pneumatic flexible actuator, H _pfor the actual maximum elongation length of Pneumatic flexible actuator, the energy conversion efficiency that λ is Pneumatic flexible actuator, n is polytropic exponent.

In conjunction with Fig. 6, have:

$F=\mathrm{\&lambda;}\&times;p\&times;N\&times;\mathrm{\&pi;}({\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HDA0000445805710000011.png"\; state="\{\{state\}\}">r</figure-callout>}}_2^2-r_1^2)$

R wherein ₁=(D+h)/2

r ₂=(D+h)/2+l

Another: 2 π R '=π h+2l

H=h·N

R′=K·R

Meanwhile, consider that Pneumatic flexible actuator is subject to the impact of spiral elastic pipes elastic force and outer establishment fleece frictional force in actual elongation process, Pneumatic flexible actuator cannot be elongated to theoretical greatest length H _maxtherefore, introduce extended length correction coefficient

revise the theoretical power output model of Pneumatic flexible actuator.

Following table has provided Pneumatic flexible actuator K under different input pressures _pvalue example.

Input pressure	0.05MPa	0.1MPa	0.15MPa	0.2MPa	0.25MPa	0.3MPa
							Correction coefficient	1.17	1.07	1.02	1	1	0.98

Thus, the driving force mathematical model that can derive Pneumatic flexible actuator is:

$F=\frac{{\mathrm{\&lambda;p\&pi;}}^2{(\mathrm{\&pi;}-2)\left(K_{p}H\right)}^2}{4N}-\mathrm{\&lambda;}{\mathrm{p\&pi;}}^2[\mathrm{KR}(\mathrm{\&pi;}-1)+\frac{D}{2}]\left(K_{p}H\right)+\mathrm{\&lambda;pNKR}{\mathrm{\&pi;}}^2(\mathrm{\&pi;KR}+D)---\left(1\right)$

(1) quiet rigidity model

In the constant situation of supply gas pressure, Pneumatic flexible actuator static rigidity can be expressed as

K _j=dF/dH

To formula (1) differentiate, show that the expression formula of static rigidity is:

$K_j=\frac{{\mathrm{<figure-callout\; id="2"\; label="K\; p"\; filenames="HDA0000445805710000011.png"\; state="\{\{state\}\}">K</figure-callout>}}_p^{}\mathrm{\&lambda;}{\mathrm{p\&pi;}}^2(\mathrm{\&pi;}-2)}{2N}H-K_p\mathrm{\&lambda;}{\mathrm{p\&pi;}}^2[\mathrm{KR}(\mathrm{\&pi;}-1)+\frac{D}{2}]---\left(2\right)$

(2) dynamic rate model

Pneumatic flexible actuator is when the very short time is subject to External Force Acting and produces displacement, thereby its inner volume volume changes and causes the variation of internal gas pressure, when internal gas has little time, with outer pipeline, relative flowing occurs, the rising of Pneumatic flexible actuator internal gas pressure will cause additional restoring force.At this moment the rigidity of Pneumatic flexible actuator and static rigidity are not identical, and the rigidity of Pneumatic flexible actuator is called dynamic rate in this case.

Definition $a={{\mathrm{<figure-callout\; id="2"\; label="K\; p"\; filenames="HDA0000445805710000011.png"\; state="\{\{state\}\}">K</figure-callout>}}_p}^2\mathrm{\&lambda;}\frac{{\mathrm{\&pi;}}^2(\mathrm{\&pi;}-2)}{4N},b=-K_p{\mathrm{\&lambda;\&pi;}}^2[\mathrm{KR}(\mathrm{\&pi;}-1)+\frac{D}{2}],$

C=λ NKR π ²(π KR+D):

F=p(aH ²+bH+c)

Static rigidity also can be written as:

K _j=p(2aH+b) (3)

The dynamic stress equation of Pneumatic flexible actuator can be expressed as:

F=p(2aH+b)(H-H _max) (4)

To formula (4) differentiate, the expression formula of dynamic rate can be write as:

$K_d=p(2\mathrm{aH}+b)+2\mathrm{pa}(H-H_{\max })+(2\mathrm{aH}+b)(H-H_{\max })\frac{\mathrm{dp}}{\mathrm{dH}}=K_j+K_q---\left(5\right)$

Wherein defining pneumatic stiffness is:

$K_q=2\mathrm{qa}(H-H_{\max })+\frac{\mathrm{dp}}{d\stackrel{\&OverBar;}{A}}\&times;\frac{d\stackrel{\&OverBar;}{A}}{\mathrm{dH}}\&times;(2\mathrm{aH}+b)(H-H_{\max })---\left(6\right)$

Be that dynamic rate equals static rigidity K _jwith air pressure stiffness K _qsum.

Suppose that Pneumatic flexible actuator is when moment is subject to External Force Acting, internal gas has little time to exchange with ambient atmos, according to The Ideal-Gas Equation

pV ⁿ=C (7)

Above,

for the working chamber volume of Pneumatic flexible actuator,

equivalent cross-sectional area for Pneumatic flexible actuator.

Formula (7) is carried out to differentiate, draws:

$\frac{\mathrm{dp}}{d\stackrel{\&OverBar;}{A}}=\frac{-\mathrm{np}}{\stackrel{\&OverBar;}{A}}---\left(8\right)$

Again according to the power output of Pneumatic flexible actuator:

$p({\mathrm{<figure-callout\; id="2"\; label="aH"\; filenames="HDA0000445805710000011.png"\; state="\{\{state\}\}">aH</figure-callout>}}^2+\mathrm{bH}+c)=\mathrm{\&lambda;pN}\stackrel{\&OverBar;}{A}---\left(9\right)$

$\frac{d\stackrel{\&OverBar;}{A}}{\mathrm{dH}}=(2\mathrm{aH}+b)$

Through simplifying, draw pneumatic stiffness

$K_q=p(H-H_{\max })[2a-\frac{n{(2\mathrm{aH}+b)}^2}{{\mathrm{<figure-callout\; id="2"\; label="aH"\; filenames="HDA0000445805710000011.png"\; state="\{\{state\}\}">aH</figure-callout>}}^2+\mathrm{bH}+c}]---\left(10\right)$

More than comprehensive, the dynamic rate expression formula that can obtain Pneumatic flexible actuator is:

$\left\{\begin{array}{c}{K}_d=K_j+K_q\\ K_j=\frac{{\mathrm{<figure-callout\; id="2"\; label="K\; p"\; filenames="HDA0000445805710000011.png"\; state="\{\{state\}\}">K</figure-callout>}}_p^{}\mathrm{\&lambda;p}{\mathrm{\&pi;}}^2(\mathrm{\&pi;}-2)}{2N}H-K_p{\mathrm{\&lambda;p\&pi;}}^2[\mathrm{KR}(\mathrm{\&pi;}-1)+\frac{D}{2}]\\ K_q=p(H-H_{\max })[2a-\frac{{n(2\mathrm{aH}+b)}^2}{{\mathrm{<figure-callout\; id="2"\; label="aH"\; filenames="HDA0000445805710000011.png"\; state="\{\{state\}\}">aH</figure-callout>}}^2+\mathrm{bH}+c}]\end{array}\right.$

From dynamic rate expression formula, can find out, the parameter that affects Pneumatic flexible actuator rigidity is supply gas pressure and each geometric parameter.Therefore in actual control, can control by controlling the supply gas pressure of Pneumatic flexible actuator the rigidity of Pneumatic flexible actuator.Fig. 5 example that to be Pneumatic flexible actuator dynamic stiffness change with the variation of supply gas pressure.

Claims (3)

1. the stiffness variable knee-joint rehabilitation training device with Biological Strength feedback, comprise force application structure, carrier structure, force application structure comprises Rodless cylinder (2), the first Pneumatic flexible actuator (4), the second Pneumatic flexible actuator (6), sliding pair (10), and sliding pair (10) is comprised of rod member and slide block; Carrier structure comprises thigh bar (11), shank bar (13), between shank bar (13) and thigh bar (11), forms revolute pair; Characterized by further comprising Biological Strength detecting signal unit, control unit, wherein Biological Strength detecting signal unit comprises travel switch, the angular transducer (27) of surface electrical pole piece (21), signal conditioner (22), data collection and control system (23), position indication use, the trip switch is comprised of magnetic switch (25) and approach switch (26), and control unit comprises computer (24), proportional flow control valve (28), proportional pressure valve (29), switch valve (30), solenoid directional control valve (31), Programmable Logic Controller (32);

Described the first Pneumatic flexible actuator (4), the second Pneumatic flexible actuator (6) respectively connect a proportional flow control valve, two QI KOU of Rodless cylinder (2) connect respectively a proportional flow control valve, each proportional flow control valve connects a proportional pressure valve, each proportional pressure valve connects a switch valve, each switch valve is all connected with solenoid directional control valve (31), and proportional flow control valve (28), proportional pressure valve (29), switch valve (30) and solenoid directional control valve (31) are communicated with by trachea;

Surface electrical pole piece (21) is connected by data wire with signal conditioner (22), Programmable Logic Controller (32) is connected by data wire with computer (24), magnetic switch (25), approach switch (26), angular transducer (27), switch valve (30), solenoid directional control valve (31) respectively, and data collection and control system (23) is connected by data wire with computer (24), signal conditioner (22), proportional pressure valve (29), proportional flow control valve (28) respectively; Plural magnetic switch (25) is installed in the groove of outer surface of cylinder block of Rodless cylinder (2), the position that magnetic switch (25) is placed can be adjustable in the travel range of cylinder along Rodless cylinder (2) axis direction, the travel position of the piston of Rodless cylinder during for detection of rehabilitation training (2); In the rod member both sides of sliding pair (10), approach switch (26) is set, angular transducer (27) be arranged on thigh bar (11) and and shank bar (13) between rotation vice division chief, and concentric with this revolute pair.

2. the stiffness variable knee-joint rehabilitation training method with Biological Strength feedback, it is characterized in that carrying out on the knee-joint active-passive rehabilitation training device of bidirectional flexible, surface electrical pole piece (21) is affixed on to the corresponding muscle of the lower limb of undergoing training place when carrying out rehabilitation training, with the Biological Strength producing due to muscle contraction in test during rehabilitation training, this Biological Strength signal sends by data line amplification and the Filtering Processing that signal conditioner (22) carries out signal to, and by the signal after data collection and control system (23) acquisition process, signal after data collection and control system (23) is processed signal conditioner (22) carries out sending computer (24) to after mould/number conversion, computer (24) carries out eigenvalue RMS extraction to Biological Strength signal, the assessment and analysis of signal power, the control instruction that data collection and control system (23) is assigned computer (24) carries out sending to proportional flow control valve (28) and proportional pressure valve (29) after D/A switch, the control instruction that proportional flow control valve (28) and proportional pressure valve (29) provide according to computer (24) regulates the size of gas supply flow and supply gas pressure, by the break-make situation of Programmable Logic Controller (32) gauge tap valve (30) and solenoid directional control valve (31) respective electrical Magnet, pneumatic circuit is carried out to sequentially-operating control, to control the process of rehabilitation training.

3. the stiffness variable knee-joint rehabilitation training method with Biological Strength feedback according to claim 2, it is characterized in that driving the end passing ratio flow valve (28) of stroke and the supply gas pressure that proportional pressure valve (29) is controlled the first Pneumatic flexible actuator (4) or the second Pneumatic flexible actuator (6), change the rigidity of Pneumatic flexible actuator, to meet the different rehabilitation stage, device for rehabilitation is become to the requirement of rigidity, i.e. the dynamic stiffness K of Pneumatic flexible actuator _dfor quiet stiffness K _jwith air pressure stiffness K _qsum:

$\left\{\begin{array}{c}{K}_d=K_j+K_q\\ K_j=\frac{K_p^2\mathrm{\&lambda;p}{\mathrm{\&pi;}}^2(\mathrm{\&pi;}-2)}{2N}H-K_p{\mathrm{\&lambda;p\&pi;}}^2[\mathrm{KR}(\mathrm{\&pi;}-1)+\frac{D}{2}]\\ K_q=p(H-H_{\max })[2a-\frac{{n(2\mathrm{aH}+b)}^2}{{\mathrm{aH}}^2+\mathrm{bH}+c}]\end{array}\right.$

In formula,

for the extended length correction coefficient of Pneumatic flexible actuator, H _maxfor the theoretical maximum elongation length of Pneumatic flexible actuator, H _pactual maximum elongation length for Pneumatic flexible actuator.λ is the energy conversion efficiency of Pneumatic flexible actuator, p is supply gas pressure, H is the active length of Pneumatic flexible actuator, N is the spiral elastic pipes number of plies of Pneumatic flexible actuator, R is the outer ring radius of the spiral elastic pipes of Pneumatic flexible actuator while being expanded to circle, the radius changing rate of the spiral elastic pipes that K is Pneumatic flexible actuator, and D is guide rod diameter, n is polytropic exponent

$b=-K_p{\mathrm{\&lambda;\&pi;}}^2[\mathrm{KR}(\mathrm{\&pi;}-1)+\frac{D}{2}],$ c=λNKRπ ²(πKR+D)。

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