Patents by Inventor Karl J. Astrom

Karl J. Astrom has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Method and an apparatus for automatically tuning a process regulator
    Patent number: 4758943
    Abstract: Method for adjusting the setting of a digital process regulator on the basis of the result obtained from a simple relay feedback experiment. When an adjustment of the regulator setting is to be made, the relay feedback is connected in the control feedback circuit instead of the regulator in order to cause self-oscillation. The self-oscillation signal is utilized to calculate the new setting of the regulator.
    Type: Grant
    Filed: December 3, 1986
    Date of Patent: July 19, 1988
    Assignee: Hightech Network AB
    Inventors: Karl J. Astrom, Tore Hagglund
  • Method and an apparatus in tuning a PID-regulator
    Patent number: 4549123
    Abstract: In tuning a regulator (2) of the PID-type of a process (1) in a feed back system where the process and the regulator has a transfer function G(s) in common, a method is proposed for bringing the system into self oscillation for measuring the amplitude and frequency of the oscillation and tuning the regulator in dependence of the measurements obtained. A circuit function (NL) having non-linear characteristic and a describing function N(A) is introduced into the system in series to the process for acting on the regulator signal (e). Self oscillation is obtained if G(i.omega.).multidot.N(A)=-1 for at least one value of the angular frequency .omega. and the amplitude A of the regulator signal (e). An apparatus for performing the method is disclosed.
    Type: Grant
    Filed: March 21, 1983
    Date of Patent: October 22, 1985
    Assignee: NAF Controls AB
    Inventors: Tore Hagglund, Karl J. Astrom