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  • 12:27 PM, Friday, 05 Mar 2021

Department of Avionics
Sam K Zachariah, Ph.D.
Adjunct Professor
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  • Ph.D.(Hybrid-state Driven Autonomous Control of Planar Bipedal locomotion), IIST
  • M.Tech (Control & Instrumentation) IIT, Bombay(1993)
  • B.Tech (Electronics & Communication), College of Engineering, Trivandrum (1987)

Course Offered
  • Control systems (Undergraduate)
  • Modelling and Control of Robotic systems (Undergraduate and Postgraduate)
  • Applied Linear Algebra (Postgraduate)
  • Control systems Laboratory (Undergraduate)

    • 20 years of experience in VSSC,ISRO in the areas of modelling, control and simulation of servo actuation systems for launch vehicles.
    • 3 years of experience as Division Head, Control Design division (CLD), VSSC responsible for the design of Digital autopilot of launch vehicles.
    • 10 years of teaching experience in IIST as faculty in the Department of Avionics for UG and PG courses.
    • 10 years of research experience in IIST in the field of locomotion control of Humanoid robot.

Research Work / Area
  • Autonomous locomotion control of  Humanoid Robot
Field of Specialization:
  • Nonlinear mathematical modeling, compensator design and simulation of electro mechanical and electro hydraulic servo actuation systems and components.
  • Digital Autopilot Design of Launch Vehicles.
  • Design and realization of Mechatronic systems.
  • Modelling, Control and Simulation of Advanvced Robotic systems such as Humanoids.
Awards and Recognition:
  1. Space/ASI Gold Medal for 2006 for the meritorious contributions to ISRO programmes
  2. Prof. G.N. Revankar Award for the highest score for M.Tech in the Dept. Of Electrical Engg., IIT, Bombay , 1993
Patents Filed:
  1. Mechatronic test rig for actuators – A Universal test rig for mechatronically realizing generic load dynamics for testing actuation systems
Professional Experience:

Joined Vikram Sarabhai Space Centre (VSSC) of ISRO in September 1987 and served in various capacities as given below till he joined IIST in January 2010 as Adjunct Professor on a working arrangement basis.

  • Division Head, Control Design Division (CLD) , VSSC
  • Deputy Project Director (Control Design), Human in Space Programme (HSP)
  • Section Head, Servo Analysis and Design Section
  • Engineer-in-charge, Servo analysis and design section
  • Project Manager (Servo analysis and Design), Reusable Launch Vehicle (RLV-TD) Project
  • Deputy System Manager (Servo design and Simulation), DALIA project
  • Team Leader, Technology Development Programme on Mechatronic Test Rig for Actuators (METRA)
  • Team Leader, Technology Development Programme on LVDT Indigenization for Launch vehicle actuators
Major contributions
  1. Development of an iterative method for extending Quantitative Feedback Theory (QFT) to MIMO problems without the conservatism associated with normal MIMO QFT methods.
  2. Development of nonlinear mathematical models of all servo actuation systems for PSLV, GSLV, GSLV Mk3 and RLV-TD which are currently used for integrated vehicle level simulation test beds like ICOMETS, SITARA,OILS and HLS.
  3. Compensator design of various electro hydraulic and electro mechanical servo actuation systems used in GSLV, GSLV Mk3 and RLV-TD.
  4. Stabilization of 3-axis gimbal system for Air borne synthetic aperture radar developed for SAMCS project.
  5. Compensator design of 3-axis high frequency angular motion simulator (AMS) indigenously developed for PSLV/GSLV NGC simulations.
  6. Development of nonlinear mathematical model and compensator design for the indigenously developed electro hydraulic actuators controlled by Direct Drive Valves (DDV) with dual redundancy for usage in aircraft rudder and elevon actuation systems.
  7. Development of a novel concept of mechatronically realizing actuation system’s load dynamics and demonstrated the same to Chairman, ISRO.
  8. Compensator design of isothermal heating furnace (IHF) of Space capsule Recovery Experiment (SRE).
  9. Electromagnetic design of LVDT using finite element software FEMLAB for launch vehicle actuation systems.
  10. Developed a novel fault detection scheme for the dual redundant DDV based electro hydraulic actuation systems of GSLV Mk3 which got implemented using nonlinear analog electronic circuits for the solid booster stage and liquid first stage.
  11. Developed the integrated nonlinear mathematical for the liquid stage rocket engine (VIKAS HP engine) used in GSLV to reproduce the transient and steady state engine behaviors. This model has been used for the engine failure analysis of GSLV- F02.
  12. Initiated a technology development programme for the “Simultaneous Localization and Mapping (SLAM)” for the autonomous navigation of planetary robotic missions.
  13. Responsible for the Digital Autopilot (DAP) design and onboard control software development for PSLV continuation flights (C9 to C15 series) and GSLV D3 as the Head of Control Design Division, VSSC.
Internal Technical Reports :
  • More than 75 internal technical reports covering various aspects of aero space servo actuation systems and launch vehicle control systems.
  1. B.B.Das and Sam K. Zachariah, "Optimal pulse-position pulse width-modulated control of sampled data position servo system", IEE Proceedings Vol. 137, Pt. D, no.5, Sept 1990,
  2. Sam K. Zachariah and B.B.Das,"Servo design for Launch vehicle control system”, presented in the workshop on Flight control systems at Bangalore organized by Association for Advancement of fault tolerant and Autonomous Systems on Dec 15-16,1995
  3. B.B.Das and Sam K. Zachariah,“Optimal controller synthesis for robust servo mechanism problem” presented in National Systems Conference, 1997.
  4. Sam K. Zachariah and B.B.Das,“Modeling and analysis of an Electro hydraulic servo system for Launch Vehicle Applications” Presented in National workshop on Aerospace servo systems held on 25th & 26th June, 1998 at VSSC, Trivandrum.
  5. Sam K. Zachariah and B.B.Das,“Parameter estimation of an Electro mechanical actuator using genetic algorithm” presented in National System Conference held in Dec 99 at BHU, Varanasi.
  6. Sam K. Zachariah and B.B.Das,“Mathematical modeling and simulation of a nonlinear Electromechanical servo system” presented in National Systems conference 2000 held in Dec 2000 at ISAC, Bangalore.
  7. Sam K. Zachariah and B.B.Das,“Direct displacement modeling of Electro hydraulic actuation system for launch vehicles” presented in National systems conference held in Nov 2002 at Hyderabad.
  8. “A study on the effect of radial clearance and underlap in servo valve on the performance of an electro hydraulic actuation system” presented in the National systems conference held in Dec 2003 at IIT, Kharagpur. which received the Best theory paper award and published in the SSI journal, Parithanthra.
  9. Sam K. Zachariah and B.B.Das,“Nonlinear modeling of Launch Vehicle electro hydraulic servo actuation systems” presented in EMCHAFT 2003 – FPSI Conference, Chennai held at IIT, Madras on 10th & 11th Jan 2003.
  10. Gopal Jee, Kapil Sharma, Karnena Koteswara Rao, Sam K. Zachariah , V. Brinda, V. R. Lalithambika, M. V. Dhekane, Girish. S. Deodhare and Shyam Chetty, "Evolution of attitude control law of an Indian re-entry launch vehicle", International Journal of Advances in Engineering sciences and Applied mathematics, Dec 2014, Vol.6, pp 148-157
  11. Gopal Jee, Sam K. Zachariah, M.V.Dhekane and B.B.Das, "Comparison of LQR, Feedback Linearization and Back Stepping based Control Laws for Suppressing Wing Rock"
  12. Sam K. Zachariah and Thomas Kurian, "Hybrid-state driven autonomous control for planar bipedal locomotion", Robotics and Autonomous systems, vol.83, pp.115-137, 2016
  13. Sam K. Zachariah and Thomas Kurian, "Hybrid-state driven autonomous control for planar bipedal locomotion over randomly sloped non-uniform stairs", Robotics and Autonomous systems, vol.97, pp.18-39, 2017
  14. Sam K. Zachariah, "Hybrid-state driven autonomous control for planar bip edal locomotion ", Ph.D. Thesis, IIST, 2019, Published in Research Gate