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Herbert K. Weiss

Bio: Herbert K. Weiss is an academic researcher from Massachusetts Institute of Technology. The author has contributed to research in topics: Servomechanism & Inertia. The author has an hindex of 4, co-authored 6 publications receiving 46 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, the authors developed a method for the transient and steady-state analysis of relay-type servomechanisms, with intermittently applied torque, inertia, viscous friction, dry friction, finite spacing of the controlling contacts, constant delay time in torque change, and stabilization by "flip-flop/' "front-lash," and anticipatory circuits.
Abstract: Methods are developed for the transient and steady-state analysis of relay-type servomechanisms, with intermittently applied torque, inertia, viscous friction, dry friction, finite spacing of the controlling contacts, constant delay time in torque change, and stabilization by "flip-flop/' "front-lash," and anticipatory circuits. Solutions are obtained through representation of the motion of the servomechanism in the position-velocity or "phase" plane. In this plane, the discontinuous character of the driving torques, dry friction, delay time, finite contact spacing, and certain types of stabilizers, defines boundaries that are frequently straight lines. The boundaries divide the phase plane into a number of regions, within each of which the motion of the servomechanism is determinable by elementary means. Theorems and semigraphical constructions are developed for the rapid representation of the transient and steady-state motion in the phase plane, and simple constructions are demonstrated for converting the phase-plane plots to conventional time plots. Guided by phase-plane representations, exact mathematical solutions are obtained for a number of cases of interest. A method is developed for testing the physical significance of the tnathematically derived steady-state solutions. Finally, the techniques developed are applied to the comparative examination of several methods for suppressing "hunt ing" of the servo. The analysis indicates an anticipatory signal to be the most promising for control of torque application in a high performance relay servomechanism.

23 citations

Patent
01 Jun 2006
TL;DR: In this paper, a high pressure discharge lamp is fitted with a discharge vessel that has an inside volume with an inside length IL and a maximum inside diameter ID, and that is subdivided into a middle region of constant inside diameter IL and two end regions of variable inside diameter, an electrode projecting into the discharge vessel in each case.
Abstract: The high pressure discharge lamp is fitted with a discharge vessel that has an inside volume with an inside length IL and a maximum inside diameter ID, and that is subdivided into a middle region of constant inside diameter ID and two end regions of variable inside diameter, an electrode projecting into the discharge vessel in the end region in each case. In addition, the discharge vessel has an aspect ratio of 2.5 to 8, preferably 3 to 6, the end region exhibiting a given length LRD in which the inside diameter is reduced to at least 85% of ID.

10 citations

Journal ArticleDOI
TL;DR: In this article, the general theory of the constant speed control is reviewed for an error and rate of change of error control applied to a system possessing inertia but no damping or inherent speed stability.
Abstract: The general theory of the constant speed control is reviewed for an "error" and "rate-of-change of error" control applied to a system possessing inertia but no damping or inherent speed stability. I t is shown that the most satisfactory control is one which has a high natural frequency, small inertia, and little or no Coulomb friction. Viscous damping is shown to have a less detrimental effect on the response of the control than control inertia, and the general conclusion is drawn that stability of the motion is secured by viscous damping in the control, while good performance is obtained by keeping the inertia of the control small.

6 citations

Journal ArticleDOI
TL;DR: In this article, the effect of aerodynamic parameters of the propeller on the performance of the overall system is established, and the advantage of nonlinear control characteristics is noted and demonstrated by calculation of control response for a typical combination of propeller, engine, control, and airplane.
Abstract: A theoretic investigation of the performance of constant-speed propeller controls, operating with various types of anticipatorycomponents and several classes of lag, is undertaken over the performance range of the airplane. The effect of aerodynamic parameters of the propeller on the performance of the overall system is established. The advantage of nonlinear control characteristics is noted and demonstrated by calculation of control response for a typical combination of propeller, engine, control, and airplane, A number of charts are presented in dimensionless form, giving the propeller derivatives involved in control design. Charts showing stability requirements for a control system subject to both firstand second-order lag are supplied, as are charts for stability determination of control systems with constant time lag.

4 citations

Patent
10 Oct 2007
TL;DR: In this paper, a mercury-free low pressure discharge lamp with an ionizable filling is described, where the surface temperature of the discharge vessel and the temperature of ionizable fluid can be adjusted at least in some sections such that an emitting substance can produce the radiation required for the excitation of the luminescent substance.
Abstract: The invention relates to a mercury-free low pressure discharge lamp with a discharge vessel having an ionizable filling. The surface temperature of the discharge vessel, and thus the temperature of the ionizable filling, can be adjusted at least in some sections such that an emitting substance can produce the radiation required for the excitation of the luminescent substance. The temperature of the fluid is preferably adjusted in a temperature control circuit, using a temperature sensor, a pump and a heating device.

3 citations


Cited by
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Book ChapterDOI
01 Jan 1995
TL;DR: Analysis of linear systems with relay feedback is a classical field and the early work on relay feedback was motivated by using relays as amplifiers, but these applications became less interesting, because the development of electronic technology made relay amplifiers obsolete.
Abstract: Analysis of linear systems with relay feedback is a classical field The early work on relay feedback was motivated by using relays as amplifiers These applications became less interesting, because the development of electronic technology made relay amplifiers obsolete A discussion of relay feedback is found in the classical book [12] Analysis of systems with relay feedback were given by [27],[10],[11],[22],[23],[24],[25],[7],[16],[18],[19] Much of the analysis of relay feedback has been done using the describing function, see [5] and [8] An interesting discussion of the validity of the describing function approximation is found in 20 Exact conditions for limit cycle oscillations under relay feedback were developed in the papers by Hamel and Tsypkin Tsypkin’s work is particularly interesting because of its close relation with the approximate methods An extensive treatment is found in [26], which is an English translation of a book that was first published in Russian in 1974

143 citations

PatentDOI
TL;DR: In this paper, a metal-halide lamp with a discharge vessel having a ceramic wall was described, where the discharge vessel comprises two electrodes whose tips are arranged at a mutual distance EA. The relation EA/Di > 5 is complied with.
Abstract: The invention relates to a metal-halide lamp provided with a discharge vessel having a ceramic wall. The discharge vessel comprises two electrodes whose tips are arranged at a mutual distance EA. The discharge vessel has an inside diameter Di which extends over said distance EA. The relation EA/Di > 5 is complied with. According to the invention, the discharge vessel has a filling which comprises, in addition to Hg and CeJ3, also LiJ.

66 citations

Journal ArticleDOI
TL;DR: In this paper, the authors proposed to keep the velocity of flow below that of sound in the whole field of flow in the contraction cone, where the highest velocity is reached at the wall of the cone.
Abstract: In desicning the contraction cone for a wind tunnel, the usual design condition is that the velocity at the end of the cone must befairly uniform. However, if the curvature of the wall along the flow direction is too large at certain points, local velocities at these points may exceed the uniform velocity at the end of the contraction cone. There are then regions of adverse pressure gradient and the boundary layer may separate from the wall. Furthermore, if the velocity at the end of the contraction cone is very high, say about 0.9 that of the sound, an additional factor enters — namely, the danger of compressibility shock. This danger can be avoided by keeping the velocity of flow below that of sound in the whole field of flow. In the particular case of a contraction cone, the highest velocity is reached at the wall of the cone. Therefore, if the velocity at the wall is made to increase monotonically † from the beginning of the cone to the end of cone the velocity in the cone will be always less than that of sound, provided that the velocity at the end of the contraction cone is less than the velocity of sound. The pressure along the wall will then be decreasing monotonically. Hence, the danger of boundary layer separation is also avoided.

50 citations