CIFERĀ® News

July 1, 2016

The CIFER® team is proud to announce the new CIFER Version 6.3.00 release for Windows Vista, Windows 7, Windows 8 and Windows 10.  In this release, you will find a number of new features and updates since the 6.2.00 release.  Here are some of the highlights:

  • In DERIVID, on the Tabulate Results screen, and in the DERIVID Eigenvalue Utility, eigenvalue output now shows both the original real and imaginary presentation as well as a new magnitude and phase listing for each eigenvalue.
  • A new transfer function output feature was added to the DERIVID Tabulate Results screen and the DERIVID Eigenvalue Utility.  These new outputs will produce an equivalent system of reduced transfer functions in shorthand notation for the current DERIVID model.
  • In DERIVID, the Matrix Setup screen now provides a new option to fix or free all named derivatives across the entire matrix, in addition to doing so just for the displayed matrix elements.
  • In DERIVID and QPlot and Case Plot utilities, the coherence plots now can produce one or more lines of constant value at 0.5, 0.6 and/or a user-entered custom value so that it is easier for users to read off frequency range that meets the desired coherence.
  • Immediately after installation, CIFER will set the active database to the class database (CIFERCLS) as the default database instead of pointing to an empty configuration.  This prevents CIFER from presenting an immediate error to new users when trying to browse for cases without an active database.
  • The User's Guide has been updated to reflect the changes and updates to the software since the 6.2.00 release.
  • Various bug fixes and many enhancements to the computational programs and utilities based on user feedback have been implemented since the 6.2.00 release.  All users are urged to update as soon as possible to remove certain identified bugs.
  • For a list of enhancements and bug fixes, please see C:\CIFER_Pro\documentation\features.6.3.00 (or C:\CIFER_Student\...).  You can use Notepad to view this file.
  • MATLAB R2014b, R2015a and R2015b are now supported in addition to R2012b through R2014a.  Users who would like to associate CIFER with the three newer versions of MATLAB must upgrade CIFER to the new 6.3.00 release.
  • In order to allow users who either do not have MATLAB, or have only limited seats of MATLAB available at their sites, we continue to provide two installation options of CIFER in this release: The MATLAB Edition, which associates CIFER with installed MATLAB on the target systems, and the Standalone Edition, which comes with its own MATLAB run-time and does NOT require separate purchase of a MATLAB license.  These two editions were first made available beginning with CIFER 5.4.00.

As a reminder, for the MATLAB Edition, if you are installing the software on a 64-bit system, you can only associate CIFER with the 32-bit versions of MATLAB.  On the other hand, for the Standalone Edition, CIFER will operate under the 32-bit compatibility mode on a 64-bit Windows system.

Please note also that support for Windows Vista and/or some of the older versions of MATLAB may be removed in any particular future version of CIFER.  Any deprecated operating system or MATLAB version, if known, will be announced at least one version in advance.

Accordingly, MATLAB R2012b will be supported in this release but not in future releases.  Please note that The MathWorks would not provide full technical support for this release as well at the time of the next anticipated CIFER release, so you are strongly encouraged to upgrade to newer versions of MATLAB when possible.

Under this policy, support for MATLAB R2011b and R2012a was discontinued for CIFER 6.3.00.


April 2016

SUBJECT: Publication of U.S. Army Aviation Development Directorate SPECIAL REPORT RDMR-AF-16-01: Tobias, E. L., and Tischler, M. B., "A Model Stitching Architecture for Continuous Full Flight-Envelope Simulation of Fixed-Wing Aircraft and Rotorcraft From Discrete-Point Linear Models."

The comprehensive report on model stitching for full flight-envelope simulation has been published by the Aviation Development Directorate (AMRDEC). This report details the development of a model stitching simulation architecture, which allows continuous, full flight-envelope simulation based on a limited number of discrete-point linear models and trim data.

The required linear point models and trim data can be obtained from linearization output of a physics-based nonlinear non-real-time model or from flight-test system identification results. Extrapolation methods within the stitched model and validated in this report permit accurate simulation of off-nominal aircraft loading configurations, and variations in altitude, which together minimize the required number of point models.

Applications of the model stitching approach are presented in the report to a model of the CJ1 business jet and to a model of a UH-60 utility helicopter. Flight-test implications for the development of stitched models from flight-identified point models are presented for fixed-wing and rotorcraft applications.

The wide ranging applications of this stitched model approach include: detailed analysis of handling-qualities and control laws, extrapolation of identified models to off-nominal conditions, desktop simulation, hardware in-the-loop simulation, pilot-in-the-loop realtime simulation, and detailed analysis of handling-qualities and control laws.


February 3, 2015

 Dr. Tischler's short course, Rotorcraft Flight Dynamics Model Identification and Flight Control Design using CIFER® and CONDUIT®, will be held on May 4, 2015 in Virginia Beach, VA in conjunction with the upcoming AHS 71st Annual Forum. This is a unique opportunity to learn and review the methods and applications of aircraft and rotorcraft system identification and flight control design directly from Dr. Tischler.

This course will cover practical methods and applications of system identification methods to determine and validate flight dynamics models of rotorcraft from flight test and simulation data. It will also cover practical flight control design and optimization methods to meet modern handling-qualities and flight control specifications. Many flight application examples based on the instructor's broad experience base will be presented throughout the course to demonstrate the methods and results.

The course would be beneficial to new and experienced rotorcraft engineers, researchers, academia, flight test engineers and pilots, and managers interested in an overview of advanced rotorcraft flight dynamics modeling and flight control tools, typical results, and project payoffs. Participants will receive a notebook with all of the course slides and can purchase a signed copy of Dr. Tischler's book on Aircraft and Rotorcraft System Identification for a discounted price.

The registration link is https://vtol.org/annual-forum/registration-information. Please take note of the Early Registration deadline of April 2, 2015.

We look forward to seeing you at the course. Please see the attached flyer or contact us for additional details.


December 19, 2014

The CIFER® team is proud to announce the new CIFER Version 6.2.00 release for Windows Vista, Windows 7 and Windows 8.  In this release, you will find a number of new features and updates since the 6.1.00 release.  Here are some of the highlights:

  • A new Disturbance Rejection Bandwidth (DRB) program has been added.  This utility computes the disturbance rejection bandwidth (DRB) as well as the disturbance rejection peak (DRP) for the provided frequency response as required by the ADS-33 test guide.
  • A new DERIVID/VERIFY Case Summary program has been added.  This program generates, for a DERIVID case, a detailed summary report that contains all the information about the case setup and results, as well as the associated time histories and frequency responses used by the case.  Additionally, if a related VERIFY case is selected, the corresponding setup information and results are also summarized in the report.
  • The User's Guide has been updated to reflect the changes and updates to the software since the 6.1.00 release.
  • Various bug fixes and many enhancements to the computational programs and utilities based on user feedback have been implemented since the 6.1.00 release.  All users are urged to update as soon as possible to remove certain identified bugs.
  • For a list of enhancements and bug fixes, please see C:\CIFER_Pro\documentation\features.6.2.00.  You can use Notepad to view this file.
  • MATLAB R2013a, R2013b and R2014a are now supported.  Users who would like to associate CIFER with these versions of MATLAB must upgrade CIFER to the new 6.2.00 release.
  • Please note that MATLAB R2014b is NOT supported in this release due to graphics compatibility issues with this version of MATLAB.  The development team is working on resolving these incompatibility issues and a special update version may be released prior to the next major release.
  • In order to allow users who either do not have MATLAB, or have only limited seats of MATLAB available at their sites, we continue to provide two installation options of CIFER in this release:  The MATLAB Edition, which associates CIFER with installed MATLAB on the target systems, and the Standalone Edition, which comes with its own MATLAB run-time and does NOT require separate purchase of a MATLAB license.  These two editions were first made available beginning with CIFER 5.4.00.

As a reminder, for the MATLAB Edition, if you are installing the software on a 64-bit system, you can only associate CIFER with the 32-bit versions of MATLAB.  On the other hand, for the Standalone Edition, CIFER will operate under the 32-bit compatibility mode on a 64-bit Windows system.

Please note also that support for Windows Vista and/or some of the older versions of MATLAB may be removed in any particular future version of CIFER.  Any deprecated operating system or MATLAB version will be announced at least one version in advance.

Accordingly, MATLAB R2011b will be supported in this release but not in future releases.  Please note that The MathWorks no longer provides full technical support for this release as well so you are strongly encouraged to upgrade to newer versions of MATLAB when possible.

Under this policy, support for MATLAB R2009b, R2010a, R2010b and R2011a was discontinued for CIFER 6.2.00.


October 22, 2014

The AIAA short course, Aircraft and Rotorcraft System Identification: Engineering Methods and Hands-on Training using CIFER® will be held on January 3-4, 2015 in Kissimmee, Florida, in conjunction with the upcoming SciTech 2015 Forum. This is a unique opportunity to learn and review the methods and applications of aircraft and rotorcraft system identification directly from Dr. Tischler.

The objectives are to: (1) review the fundamental methods of aircraft and rotorcraft system identification and illustrate the benefits of their broad application throughout the flight vehicle development process; (2) provide the attendees with an intensive hands-on training of the CIFERR system identification, using flight test data and 10 extensive Lab exercises.

Students work on comprehensive laboratory assignments using student version of software provided to course participants (requires student to bring a PC laptop running Windows 7 (preferred) or above, or a Mac laptop capable of dual-booting to Windows OS or running Windows virtual machine using Vmware Fusion or Parallels Desktop).

The many examples from recent aircraft and rotorcraft programs illustrate the effectiveness of this technology for rapidly solving difficult integration problems. The course will review key methods and computational tools, but will not be overly mathematical in content. The course is highly recommended for graduate students, practicing engineers and managers. Course includes the AIAA book "Aircraft and Rotorcraft System Identification."

This course is intended for practicing engineers and graduate students interested in learning the principles and applications of system identification for aircraft and rotorcraft. The course assumes some basic knowledge of the concepts of: dynamics, frequency-responses, transfer functions, and state-space representations. No experience with other tools is required.

More information including key topics, course outline, and registration details can be found at http://www.aiaa-scitech.org/.

We look forward to seeing you at the course. Feel free to contact us if you have any questions.


June 26, 2013

The CIFER® team is proud to announce the new CIFER Version 6.1.00 release for Windows XP, Windows Vista, Windows 7, and Windows 8.  In this release, you will find a number of new features and updates since the 6.0.00 release.  Here are some of the highlights:

  • One of the key enhancements in this release is the ability to use current versions of MATLAB.  MATLAB R2011a, R2011b, R2012a, R2012b, and R2013a are now supported.  Users who would like to associate CIFER with these versions of MATLAB must upgrade CIFER to the new 6.1.00 release.
  • The release also contains new data files associated with new exercises in the Second Edition of the AIAA book "Aircraft and Rotorcraft System Identification" by Dr. Mark B. Tischler and Mr. Robert Remple, which was released in October 2012.  More information on this new book can be found at: http://arc.aiaa.org/doi/book/10.2514/4.868207.
  • Support for Windows 8 operating system.
  • The DERIVID batch job option has been disabled due to a software incompatibility.
  • The User's Guide has been updated minimally, mostly to clarify some instructions for the command line interface.
  • Various bug fixes and many enhancements to the computational programs and utilities based on user feedback have been implemented since the 6.0.00 release.  All users are urged to update as soon as possible to remove certain identified bugs.
  • For a list of enhancements and bug fixes, please see C:\CIFER_Pro\documentation\features.6.1.00 (or C:\CIFER_Student\...).  You can use Notepad to view this file.
  • In order to allow users who either do not have MATLAB, or have only limited seats of MATLAB available at their sites, we continue to provide two installation options of CIFER in this release: The MATLAB Edition, which associates CIFER with installed MATLAB on the target systems, and the Standalone Edition, which comes with its own MATLAB run-time and does NOT require separate purchase of a MATLAB license.  These two editions were first made available beginning with CIFER 5.4.00.


As a reminder, for the MATLAB Edition, if you are installing the software on a 64-bit system, you can only associate CIFER with the 32-bit versions of MATLAB.  On the other hand, for the Standalone Edition, CIFER will operate under the 32-bit compatibility mode on a 64-bit Windows system.

Please note that support for Windows XP and/or some of the older versions of MATLAB may be removed in any particular future version of CIFER. Any deprecated operating system or MATLAB version will be announced at least one version in advance.

Accordingly, MATLAB R2009b will be supported in this release but not in future releases.  Please note that The MathWorks no longer provides full technical support for this release as well so you are strongly encouraged to upgrade to newer versions of MATLAB when possible.

Under this policy, support for MATLAB R2008a, R2008b and R2009a was discontinued for CIFER 6.1.00.

For users upgrading from previous versions:  Please note that in addition to your current version of CIFER, the MKS software also should be removed, as described in the Installation chapter.  We request positive notification from each customer that the MKS software has been removed, as we license each copy from a third party.  The MKS software became unnecessary beginning with CIFER 5.4.00, and if you are upgrading from 5.4.00, 5.4.01, or 6.0.00, you may already have removed the MKS software.


October 2012

Aircraft and Rotorcraft System Identification: Engineering Methods with Flight Test Examples, Second Edition published by the AIAA Education Series, is now released and can be found at http://arc.aiaa.org/doi/book/10.2514/4.868207. The book emphasizes engineering methods and interpretation of flight-test results, and each key method or analysis application is illustrated with the CIFER® software.

This second edition includes new in-depth chapters presenting extended model structures and identification results for large flexible transport aircraft, as well as the detailed methodology to develop a continuous full flight envelope simulation model from individual system identification models and trim test data.

Case studies based on real aircraft and rotorcraft flight-test projects are included as well as exercises for students to solve using the provided CIFER® software.


June 24, 2011

Dr. Mark Tischler will be presenting a two-day short course on system identification, Aircraft and Rotorcraft System Identification: Engineering Methods and Hands-on Training using CIFER®, at the upcoming AIAA GNC Meeting on August 6-7.

The objectives of this two-day short course are to: (1) review the fundamental methods of aircraft and rotorcraft system identification and illustrate the benefits of their broad application throughout the flight vehicle development process; and (2) provide the attendees with an intensive hands-on training of the CIFER® system identification, using flight test data and 10 extensive Lab exercises. Students work on comprehensive laboratory assignments using student version of software provided to course participants (requires student to bring latop that boots under window operating system -- XP, Vista, or Windows 7). The many examples from recent aircraft programs illustrate the effectiveness of this technology for rapidly solving difficult integration problems. The course will review key methods and computational tools, but will not be overly mathematical in content. The course is highly recommended for graduate students, practicing engineers, and managers. To register for this course, please visit AIAA.


April 26, 2011

CIFER® 6.0.00 is released. One of the key enhancements in this release is the new flexible constraints feature in DERIVID, which allows the user to define more complicated constraint equations in addition to the simple constraints as part of the model structure. This version also supports MATLAB R2008a through R2010b.


January 21, 2011

Dr. Mark Tischler will be presenting a course on system identification and flight control design, Rotorcraft Flight Dynamics Model Identification and Flight Control Design using CIFER® and CONDUIT®, at the upcoming AHS International 67th Annual Forum. This course will be useful to a broad audience including: researchers, practicing engineers, flight testing organizations, and program managers. To register for this workshop, please visit AHS.


November 19, 2010

CIFER® 5.4.01 patch is released, which fixes a critical bug in the Database Compress program, along with several other issues discovered since the 5.4.00 release.


May 6, 2010

CIFER® 5.4.00 is released, with support of MATLAB R2010a family.


June 1, 2006

We are delighted to formally announce the release of a new textbook published by AIAA on system identification of aircraft and rotorcraft written by Dr. Mark Tischler and Mr. Robert Remple:

Aircraft and Rotorcraft System Identification: Engineering Methods with Flight Test Examples

The book is a comprehensive treatment of the topic based on frequency-response methods. As indicated by the subtitle, the book focuses on practical aspects and flight test examples. There are student excersises at the end of each chapter and an instructor's solutions manual and student copy of CIFER® is available with the book. The material covered includes all the material in the CIFER® DVD training sets as well as much more detailed treatment of the theory, background, and applications of system identification methods. The book is well suited as a basis for an advanced undergraduate and graduate course as well a reference book for practicing engineers.