CN101660547A - Pneumatic artificial muscle-based method for vibration drive - Google Patents

Abstract

The invention discloses a pneumatic artificial muscle-based method for vibration drive, which comprises: firstly, according to the actual engineering needs, putting forward requirements on driving frequency, vibration amplitude and driving forces, wherein the frequency is required to be 0 to 25Hz, the vibration amplitude is 20 percent of the length of pneumatic artificial muscles, and the drivingforce ranges from 0 to 4,000N; and secondly, inversely working out control variables including air supply source pressure, drive frequency and duty ratio according to characteristic formulae (1) and (2) of the vibration amplitude and driving force of the pneumatic artificial muscles. The method is smooth in vibration movement, high in energy exchange rate, free from pollution generation and adjustable in vibration amplitude and frequency, thereby meeting some actual special requirements of engineering on vibration drive methods.

Description

Method for vibration drive based on Pneumatic artificial muscle

Technical field

The invention belongs to method for vibration drive, particularly based on the method for vibration drive of Pneumatic artificial muscle.

Background technique

Method for vibration drive commonly used at present has inertia-type, electromagnetism or electrodynamic type, hydraulic cylinder piston formula, cylinder piston type.Wherein the inertia-type method for vibration drive be the unbalanced force that in turning course, produces by the eccentric inertial mass of band as vibratory drive power, the deficiency that this method for vibration drive exists is that physical dimension is generally big, energy consumption is big, the exciting amplitude is difficult to change; The electromagnetic type method for vibration drive is made up of iron core, electromagnetic coil, armature and spring etc., the electrodynamic type method for vibration drive is made up of magnet ring, central magnetic pole and the moving coil etc. that is connected with Ac, and the deficiency that electromagnetic type and electrodynamic type exist is that structure is complicated, low frequency characteristic is poor, cost of production is relative with maintenance cost higher; Hydraulic cylinder piston formula method for vibration drive mainly is made up of oil hydraulic cylinder, piston, electrohydraulic control, hydraulic oil source etc., the deficiency of existence be hydraulic oil source must be arranged, oil pollution is arranged, physical dimension is big, cost is higher; The cylinder piston type method for vibration drive mainly is made up of cylinder, solenoid valve, source of compressed air etc., and the deficiency of existence is that the air cylinder structure that needs is complicated, cost is also higher, the system responses frequency is low, cylinder is easy to generate and creeps etc. when low frequency.

Summary of the invention

The objective of the invention is to overcome above-mentioned prior art deficiency, a kind of method for vibration drive based on Pneumatic artificial muscle is provided, this method smooth in vibration movement, energy conversion rate height, do not produce pollution, amplitude and frequency adjustable, thereby satisfy in the middle of the engineering reality some specific (special) requirements method for vibration drive.

Technological scheme of the present invention is achieved in that

Based on the method for vibration drive of Pneumatic artificial muscle, carry out according to the following steps:

1) propose driver frequency, amplitude and driving force requirement according to actual demands of engineering, frequency is 0～25Hz; Amplitude is 20% of a Pneumatic artificial muscle length; The driving force scope is 0～4000N.

2) according to Pneumatic artificial muscle amplitude and the anti-controlled quentity controlled variable of obtaining of driving force characteristic formula (1) (2), i.e. bleed pressure, driver frequency and dutycycle.

According to Pneumatic artificial muscle characteristic and system principle, calculate according to following formula based on the amplitude of the vibratory drive system of Pneumatic artificial muscle:

$\left\{\begin{array}{c}\frac{\mathrm{dP}}{\mathrm{dt}}=\frac{{\mathrm{kRTQ}}_{m}t}{V}-\frac{\mathrm{kP}}{V}\frac{\mathrm{dx}}{\mathrm{dt}}A\\ q_m={\mathrm{\&lambda;Q}}_m/f\\ M\frac{d^{2}x}{{\mathrm{<figure-callout\; id="2"\; label="dt"\; filenames="A2008100178830009H1.png"\; state="\{\{state\}\}">dt</figure-callout>}}^2}=F-F_1-F_{f1}\end{array}\right.---\left(1\right)$

In the formula:

P---Pneumatic artificial muscle cavity pressure/Pa;

V---Pneumatic artificial muscle chamber internal volume/m ³

A---Pneumatic artificial muscle equivalent action area/m ²

Q _m---enter the mass flow rate/kg in the Pneumatic artificial muscle chamber;

T---gas kelvin temperature/degree;

K---gas adiabatic exponent, k=1.4;

R---gas constant, R=287.1J/kgK;

F---the frequency/Hz of PLC output pulse signal, f=1/T;

λ---pulse duty factor;

X---the amplitude/mm of vibratory drive system;

q _m---enter the gaseous mass/kg in the Pneumatic artificial muscle chamber in one-period;

M---the equivalent mass/kg of vibratory drive system;

F---the ouput force/N of vibratory drive system;

F _F1---outside frictional force/N;

F ₁---external loading power/N.

Vibratory drive system drive power based on Pneumatic artificial muscle can be calculated by following formula:

F＝F _lX+F _f+F _v+F _Z (2)

In the formula

F _1X---the desirable ouput force/N of vibratory drive system;

F _f---the frictional force/N of vibratory drive system;

F _v---the elastic-restoring force/N of vibratory drive system;

F _Z---the damping force/N of vibratory drive system.

The present invention adopts PLC and high-speed switch valve to come controlling and driving frequency and dutycycle, adopts pressure regulator valve to regulate bleed pressure.

Technique effect of the present invention is:

1. because the Pneumatic artificial muscle working medium is a pressurized air, so be particularly suitable for should be in hazmat production occasion for this driving mode, and environmentally safe;

2. because the Pneumatic artificial muscle low frequency characteristic is better, be applicable to, and common method for driving is difficult to satisfy so low frequency requirement as low frequency and ultralow frequency (greatly about 0.1Hz-25Hz) oscillatory drive.

Description of drawings

Fig. 1 is an implementation system schematic representation of the present invention;

Fig. 2 is drive controlling method figure of the present invention;

Fig. 3 is a middle controller fundamental diagram of the present invention.

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

Embodiment

Shown in accompanying drawing 1, source of the gas 1 is connected with dividing air parcel 2, divide air parcel 2 to link to each other with gas holder 3, divide air parcel 2 to connect air pressure regulator 4, air pressure regulator 4 connects pneumatic control valve 5, and pneumatic control valve 5 connects controller 6, and pneumatic control valve 5 links to each other with Pneumatic artificial muscle 7, Pneumatic artificial muscle 7 connects oscillating body 8, and oscillating body 8 is connected with pedestal by elastic element 9.

System of the present invention comprises source of the gas (air compressor) 1, and system's executive component Pneumatic artificial muscle 7, enter the Pneumatic artificial muscle inner chamber behind pressurized air process air pressure regulator 4, the pneumatic control valve 5, the generation radial expansion of Pneumatic artificial muscle 7 alternation under compressed-air actuated effect and axial stretching distortion, thus the excitation force that produces alternation drives the vibration main body.Pneumatic control valve 5 adopts pneumatic high-speed switch valve or proportional pressure valve, Pneumatic artificial muscle 7 is one section rubber fabric pipe and bolts at two ends joint link structure of being wrapped in the specialty fibers grid, pressure stability when gas holder 3 is used to keep system works, the dynamic alternation control signal of controller 6 outputs is used to control the opening state of pneumatic high-speed switch valve, and then the control gaseous flow, elastic element 9 is a spring fastenings.Each pneumatic element is to connect by tracheae.

With reference to accompanying drawing 2, switch valve is realized switch motion under the effect of a series of pulse electrical signals, thus the air displacement of control switch valve.Pulse width modulator with the input control signal and carrier signal relatively after, the cycle of being converted into is the pulse-width signal of T.Compare with a series of sawtooth signals of making carrier wave of exporting by PLC simultaneously by control signal,, then require valve to open, otherwise require valve to close if at a time the value of control signal is greater than the value of sawtooth wave with PLC output.Obtain a series of control commands subsequently, these a series of control commands are applied on the coil of valve, open, have flow q to pass through, then do not have flow in remaining time and pass through at the time valve path that control command voltage is arranged.Pneumatic control valve adopts pulse length modulation principle to control its mean flowrate, available formula q=C _dA λ (2 p/ ρ) ^1/2The output flow of representing this time internal valve, C in the formula _dThe expression flow coefficient, A represents the opening area of valve port, λ express time T _OnWith the ratio of time T, p represents draught head, and ρ represents air density.Here the flow q of high-speed switch valve is directly proportional with pulse duty cycle λ, and pulse duty cycle λ is big more, and the mean flowrate that enters in the Pneumatic artificial muscle chamber by high-speed switch valve is big more, and the amplitude of vibratory drive system is just big more.

By drive system shown in the accompanying drawing 1, the realization frequency of okperation is that 10Hz, amplitude 5mm, driving force 750N and frequency of okperation are that 10Hz, amplitude are that 12mm, driving force are two groups of vibrations of 620N.

Obtain the controlled quentity controlled variable of above two groups of vibrations according to formula (1) (2): bleed pressure is 0.4MPa; Pulse interval is 100ms; Dutycycle gets 50% and 10% respectively.

Method for driving of the present invention adopts the opening state of PLC control pneumatic on-off valve, and then the control gaseous flow.By the pulse signal that the PLC output pulse width can be modulated, following relation is satisfied in the pulse of output: the pulse interval is 1/f=100ms; Dutycycle λ=T _ON/ T should get 10% and 50% respectively.When the vibration system amplitude when requiring amplitude, can increase high level time, bigger dutycycle just is set, when amplitude when requiring amplitude, then can reduce duty and recently meet the demands.

Though the present invention with embodiment's elaboration preferably as above, yet be not that any vibratory drive based on Pneumatic artificial muscle is 0～25Hz satisfying frequency in order to qualification the present invention, amplitude is 20% of a Pneumatic artificial muscle length; When being 0～4000N, driving force can adopt the inventive method to realize.

Claims (2)

1, based on the method for vibration drive of Pneumatic artificial muscle, it is characterized in that, carry out according to the following steps:

1) propose driver frequency, amplitude and driving force requirement according to actual demands of engineering, frequency is 0～25Hz; Amplitude is 20% of a Pneumatic artificial muscle length; The driving force scope is 0～4000N;

2) according to Pneumatic artificial muscle amplitude and the anti-controlled quentity controlled variable of obtaining of driving force characteristic formula (1) (2), i.e. bleed pressure, driver frequency and dutycycle;

According to Pneumatic artificial muscle characteristic and system principle, calculate according to following formula based on the amplitude of the vibratory drive system of Pneumatic artificial muscle:

$\left\{\begin{array}{c}\frac{\mathrm{dP}}{\mathrm{dt}}=\frac{\mathrm{kRT}{Q}_{m}t}{V}-\frac{\mathrm{kP}}{V}-\frac{\mathrm{dx}}{\mathrm{dt}}A\\ q_m=\mathrm{\&lambda;}{Q}_m/f\\ M\frac{d^{2}x}{d{t}^2}=F-F_1-F_{f1}\end{array}\right.---\left(1\right)$

In the formula:

P---Pneumatic artificial muscle cavity pressure/Pa;

V---Pneumatic artificial muscle chamber internal volume/m ³

A---Pneumatic artificial muscle equivalent action area/m ²

Q _m---enter the mass flow rate/kg in the Pneumatic artificial muscle chamber;

T---gas kelvin temperature/degree;

K---gas adiabatic exponent, k=1.4;

R---gas constant, R=287.1J/kgK;

F---the frequency of PLC output pulse signal, f=1/T;

λ---pulse duty factor;

X---the amplitude/mm of vibratory drive system;

q _m---enter the gaseous mass/kg in the Pneumatic artificial muscle chamber in one-period;

M---the equivalent mass/kg of vibratory drive system;

F---the ouput force/N of vibratory drive system;

F _F1---outside frictional force/N;

F ₁---external loading power/N;

Vibratory drive system drive power based on Pneumatic artificial muscle can be calculated by following formula:

F＝F _lX+F _f+F _v+F _Z(2)

In the formula

F _1X---the desirable ouput force/N of vibratory drive system;

F _f---the frictional force/N of vibratory drive system;

F _v---the elastic-restoring force/N of vibratory drive system;

F _Z---the damping force/N of vibratory drive system.

2, the method for vibration drive based on Pneumatic artificial muscle according to claim 1 is characterized in that, adopts PLC and high-speed switch valve to come controlling and driving frequency and dutycycle, adopts pressure regulator valve to regulate bleed pressure.

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