Air-float magneto motive friction-free suspension device
(1) technical field
The invention belongs to the modal test apparatus field, relate in particular to a kind of air-float magneto motive friction-free suspension device.
(2) background technology
When the modal test of space flight and some specific (special) requirements test specimen, the state of weightlessness of special low frequency suspension apparatus imitation specimen must be arranged, promptly simulate its solid propping up-freedom or freedom-free boundary condition by special suspension.
In order to reduce the influence of suspension apparatus to additional stiffness, additional mass and the additional friction power and the moment of test specimen, suspension should satisfy Nyquist criterion and stability criterion, when promptly requiring test specimen to hang, its rigid body hangs frequency should be lower than 1/3~1/5 of the own elasticity natural frequency of test specimen.
At present, domestic when carrying out ultralow frequency test specimen modal test, adopt methods such as elastic string suspention, when the fundamental frequency of test specimen is very low, as less than 0.1Hz the time, suspention highly reaches 15 meters and still can't satisfy the Nyquist criterion requirement, and at this moment additional mass, the non-linear effects of elastic string is also bigger, and the resultant error that tests out is bigger.Owing to lack necessary means, scientific research has been produced very big influence, existing means of testing can not adapt to the demand of development.
(3) summary of the invention
For overcome existing suspension can't satisfy Nyquist criterion requirement, additional mass when the ultra-low frequency, deficiency such as non-linear effects is big, measuring result error is big, the invention provides a kind ofly when ultralow frequency, also can satisfy Nyquist criterion, additional mass is enough little, non-linear effects is little, the air-float magneto motive friction-free suspension device that measuring accuracy is high.
The technical solution adopted for the present invention to solve the technical problems is:
A kind of air-float magneto motive friction-free suspension device, described nothing friction suspension apparatus comprises that frame, installation frame, moving beam, guide pole, mobile jib, air-flotation system and magnetic move system, and described air-flotation system comprises that two nothing friction cylinders, two identical gas-holder, nothing friction cylinders connect tracheae, accurate reduction valve; The moving system of described magnetic comprises long stroke moving-coil, vibrator iron core; Described central rack is fixed with installation frame, bottom organic frame lower installation board; Described installation frame has top board and base plate, and the little air bearing of two installation guide poles is installed above the top board, the big air bearing that mobile jib is installed; The below of base plate is equipped with the big air bearing that mobile jib is installed; The top of frame lower installation board is equipped with two does not symmetrically have the friction cylinder, do not have between friction cylinder and gas-holder by being connected the tracheae connection with the nothing friction cylinder of cylinder bore equal diameters, compressed gas source connects gas-holder by accurate reduction valve, and the piston rod that does not have the friction cylinder is hinged by being connected with moving beam; Moving beam is made up of two parts symmetrical, and mobile jib and two guide poles are installed on the moving beam, and the two ends of described mobile jib are equipped with limiting plate.
Further, the endoporus of long stroke moving-coil can be enclosed within on the vibrator iron core with moving up and down, the vibrator iron core is installed between the base plate and top board of installation frame, and long stroke moving-coil that moves up and down and moving beam distance are consistent, and long stroke moving-coil endoporus is consistent with the gap between the vibrator iron core.
Further, described nothing friction suspension apparatus comprises the detecting sensor system, and the detecting sensor system comprises baroceptor, displacement transducer, acceleration transducer, long stroke moving-coil force transducer, load force sensor; The baroceptor that is installed on the frame lower installation board is connected with nothing friction cylinder inner cavity; The displacement transducer movable part is fixed with the support that is fixed on the moving beam, and the fixed part of displacement transducer is fixed on the top board top of installation frame; Acceleration transducer is fixed on the support of moving beam side; Long stroke moving-coil force transducer simultaneously is fixed on the side of moving beam, and another side connects long stroke moving-coil mounting bracket; Load force sensor one end is fixed on the mobile jib, and the other end connects the suspension wirerope.
Technical conceive of the present invention is: air-float magneto motive friction-free suspension device is made of air-flotation system, the moving system of magnetic, detecting sensor system, frame, installation frame, moving beam, connection hinge, suspension wirerope, air bearing, mobile jib, guide pole.Air-flotation system is called again by subsystem, and the moving system of magnetic is called initiatively subsystem again.The nothing friction cylinder that air-flotation system is installed by two symmetries, two identical gas-holder, nothing friction cylinders connect tracheae, accurate reduction valve etc. and constitute.Air-flotation system provides the constant suspension force gravity with the balance test specimen, and the size of suspension force is to act on the air pressure on the piston and the product of piston area.Air pressure is regulated with accurate reduction valve.Owing to adopt there not to be friction cylinder-piston apparatus, make piston in any position of the vertical direction of cylinder, air spring power always with the test specimen gravitational equilibrium.Cylinder is connected to gas-holder by bigbore tracheae makes the volume of gas-holder become volume of cylinder.The rigidity of air spring becomes very little like this, keeps the ability of bearing big load test specimen simultaneously.Accurate reduction valve makes the mean pressure of cylinder be stabilized in setting value, makes the suspension force of not having friction cylinder-piston stable indirectly.
Initiatively subsystem is made of long stroke moving-coil vibrator and the detecting sensor system and the controller etc. of customization.
The moving system of magnetic provides non-contacting electromagnetic force according to the information that the detecting sensor system provides under controller control.To satisfy the various demands of suspension apparatus to small power.
Beneficial effect of the present invention mainly shows: 1, owing to adopt nothing friction cylinder and air bearing, but the state of weightlessness of imitation specimen, and because relative other the dynamic constrained power that influences vibration test of friction force is non-linear and non-repeatability, frictional resistance is minimum after adopting nothing friction cylinder and air bearing, does not therefore influence vibration mode test; 2, owing to adopt gas-holder and do not have the compressed-air actuated air spring of friction cylinder, so spring rate can be done very for a short time, to satisfy the vibration mode test of 0.1HZ with the lower frequency test specimen; 3, owing to adopted magnetic to move system, the information that provides according to the detecting sensor system can suppress the additional mass of servomechanism under controller control, it is controlled at becomes possibility below the 600g, and can regulate suspension height and keep the vertical direction center, the compensatory pressure fluctuation; 4, owing to limiting plate is installed, can limits the movement travel of test specimen, and can play the security protection effect at the two ends of mobile jib; 5, because crossbeam and mobile jib, guide pole all adopt the light alloy material manufacturing, and mobile jib and guide pole all adopt hollow-core construction, so the quality control that can make movement parts is in minimum; 6, owing to big air bearing, little air bearing are installed on the monoblock type installation frame, be convenient to process right alignment and the depth of parallelism requirement that guarantees between dead eye by integral body.
(4) description of drawings
Fig. 1 is the structural drawing of air-float magneto motive friction-free suspension device.
Fig. 2 is the cut-away view of Fig. 1.
(5) embodiment
Below in conjunction with accompanying drawing the present invention is further described.
With reference to Fig. 1, Fig. 2, a kind of air-float magneto motive friction-free suspension device, described nothing friction suspension apparatus comprises that frame 1, installation frame 2, moving beam 14, guide pole 4, mobile jib 7, air-flotation system and magnetic move system, and described air-flotation system comprises that two are not had friction cylinders 17, two identical gas-holder 19, do not have friction cylinder connection tracheae 18, accurate reduction valve 20; The moving system of described magnetic comprises long stroke audio frequency moving-coil 9, vibrator iron core 8; Described frame 1 middle part is fixed with installation frame 2, bottom organic frame lower installation board 22; Described installation frame 2 has top board and base plate, and 3, one big air bearing 5 that mobile jib 7 is installed of little air bearing of two installation guide poles 4 are installed above the top board; The below of base plate is equipped with the big air bearing that mobile jib is installed; The top of frame lower installation board 22 is equipped with two does not symmetrically have friction cylinder 17, do not have between friction cylinder 17 and gas-holder 19 by being connected tracheae 18 connections with the nothing friction cylinder of cylinder bore equal diameters, compressed gas source connects gas-holder 19 by accurate reduction valve 20, and the piston rod 16 that does not have friction cylinder 19 connects by being connected hinge 15 with moving beam 14; Moving beam 14 is made up of two parts symmetrical, and the both sides that mobile jib 7 and 4, two guide poles 4 of two guide poles are positioned at mobile jib 7 are installed on the moving beam 14, and the two ends of described mobile jib 7 are equipped with limiting plate.Mobile jib 7 and guide pole 3 are hollow tubular, and moving beam 14, mobile jib 7 and guide pole 3 are by the light alloy material manufacturing.
The endoporus of long stroke audio frequency moving-coil 9 can be enclosed within on the vibrator iron core 8 with moving up and down, vibrator iron core 8 is installed between the base plate and top board of installation frame 2, the long stroke audio frequency moving-coil 9 that moves up and down is consistent with moving beam 14 distances, and long stroke audio frequency moving-coil 9 endoporus are consistent with the gap of 8 of vibrator iron cores.
Described nothing friction suspension apparatus comprises the detecting sensor system, and the detecting sensor system comprises baroceptor 11, displacement transducer 6, acceleration transducer 13, long stroke moving-coil force transducer 10, load force sensor 12; Baroceptor 11 is connected with nothing friction cylinder 17 inner chambers; Displacement transducer 6 movable parts are fixed with the support that is fixed on the moving beam 14, and the fixed part of displacement transducer 6 is fixed on the top board of installation frame; Acceleration transducer 13 is fixed on the support of moving beam 14 sides; Long stroke moving-coil force transducer 10 one sides are fixed on the side of moving beam 14, and another side connects the mounting bracket of long stroke moving-coil 9; Load force sensor 12 1 ends are fixed on the mobile jib 7, and the other end connects suspension wirerope 21.
The course of work of present embodiment is: before test, earlier will be big, little air bearing feeds pressurized air, make 7 air films that are formed with rigidity of air bearing endoporus and guide pole 4 and mobile jib, thereby making guide pole 4 and mobile jib 7 friction force when motion is 0 substantially, on wirerope 21, hang test specimen then, then feed pressurized air to gas-holder 19 by accurate reduction valve 20, pressurized air in the gas-holder enters and does not have friction cylinder 17 by is connected tracheae 18 with the nothing friction cylinder of cylinder bore equal diameters, and the cylinder compressed air passes through piston rod 16 to the pressure that does not have the friction cylinder piston, connect hinge 15, moving beam 14, mobile jib 7, load force sensor 12, hang wirerope 21 and act on test specimen; Adjust accurate reduction valve 20, when making the follow-up unit gravitational equilibrium of not having friction inner pressure of air cylinder and test specimen and air-float magneto motive friction-free suspension device, adjust electric current in the long stroke moving-coil 9 of the moving system of magnetic by control system, make test specimen be in the vibration balancing center; Because two guide poles 4 in the little air bearing 3 of being installed on the moving beam 14 have limited moving beam 14 and can only do translation up and down, and can not rotate, long stroke moving-coil 9 is fixed on the side of moving beam 14 by long stroke moving-coil mounting bracket, long stroke moving-coil force transducer 10, thereby as long as when guaranteeing that vibrator iron core 8 is installed with the parallel sided of moving beam 14, consistent with regard to guaranteeing that long at the volley stroke moving-coil endoporus and gap between the vibrator iron core are that magnetic gap remains; When test specimen is subjected to the external world and forces exciting force, because the power that air-flotation system provides equals gravity all the time, but so simulated weightlessness, and test specimen is suspended on the suspension wirerope 21 times, so can do the motion under the freedom-free boundary condition of three degree of freedom, carry out the vibration mode test of test specimen; The detecting sensor system comprises baroceptor 11, displacement transducer 6, acceleration transducer 13, long stroke moving-coil force transducer 10, load force sensor 12; In test process, provide the displacement of air-float magneto motive friction-free suspension device follow-up unit and acceleration information, nothing friction cylinder internal gas pressure fluctuation information, test specimen to be subjected to force information and long stroke moving-coil to act on the acting force information of follow-up unit to control system respectively, so that the electric current to long stroke moving-coil 9 is adjusted, provide suitable electromagnetic force.