Accession Number : AD0832329

Title :   NONLINEARITIES ENCOUNTERED DURING PROPORTIONAL OPERATION OF PNEUMATIC SERVOS,

Corporate Author : GENERAL DYNAMICS SAN DIEGO CA CONVAIR DIV

Personal Author(s) : Halstenberg, R. V.

Report Date : 25 FEB 1959

Pagination or Media Count : 17

Abstract : In the cold gas testing of the various pneumatic servo systems on REA 7031, a number of results were obtained which cannot be explained by linear servo theory. These nonlinear effects were: (1) Deterioration of low amplitude frequency responses; (2) Jump resonances; (3) Subharmonic generation. The first two of these effects could be obtained repeatedly and at the time were attributed to friction and saturation respectively. Subharmonic generation was encountered from time to time but was not repeatable. There appears to be no ready explanation for the subharmonics and the analytical treatment of them has not been attempted in the present studies. An expression for the frequency at which a pneumatic servo with friction will cease motion is derived. When the results of the tests are compared with the calculated results, the correlation is very good. The deterioration of low amplitude frequency responses was undoubtedly caused by friction. A calculation of a jump resonance is carried out with saturation as the only nonlinearity and the results are compared to test results. Although the general effects of the test are shown by the calculation, there is considerable disagreement as to the height of the jump and the amplitudes at which jumps are possible. This disagreement may be caused by the use of linearized equations or excessive harmonic distortion affecting the describing function, or both. However, it is still concluded that saturation was the basic cause of the jump resonances. (Author)

Descriptors :   (*PNEUMATIC SERVOMECHANISMS, PERFORMANCE(ENGINEERING)), FRICTION, RESONANCE, TRANSFER FUNCTIONS, NUMERICAL ANALYSIS, FEEDBACK, EQUATIONS, RESPONSE, ACTUATORS.

Subject Categories : Numerical Mathematics
      Hydraulic and Pneumatic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE