Autonomous navigation system

An inertial navigation system utilizing a servo-controlled two degree of freedom pendulum to obtain specific force components in the locally level coordinate system is described. The pendulum includes a leveling gyroscope and an azimuth gyroscope supported on a two gimbal system. The specific force components in the locally level coordinate system are converted to components in the geographical coordinate system by means of a single Euler transformation. The standard navigation equations are solved to determine longitudinal and lateral velocities. Finally, vehicle position is determined by a further integration

The tone range/telemetry interferometer tracking system for support of sounding rocket payloads

Combined range rate and telemetric interferometer system for radar tracking of scientific sounding rocket

Digital to synchro converter

A digital-to-synchro converter is provided where a binary input code specifies a desired shaft angle and where an resolver type position transducer is employed with additional circuitry to generate a shaft position error signal indicative of the angular difference between the desired shaft angle and the actual shaft angle. The additional circuitry corrects for known and calculated errors in the shaft position detection process and equipment

An automated stall-speed warning system

The development and testing of a stall-speed warning system for the OV-1C was examined. NASA designed and built an automated stall-speed warning system which presents both airspeed and stall speed to the pilot. The airspeed and stall speed are computed in real time by monitoring the basic aerodynamic parameters (dynamic pressure, horizontal and vertical accelerations, and pressure altitude) and other parameters (elevator and flap positions, engine torques, and fuel flow). In addition, an aural warning at predetermined stall margins is presented to the pilot through a voice synthesizer. Once the system was designed and installed in the aircraft, a flight-test program of less than 20 hrs was anticipated to determine the stall-speed software coefficients. These coefficients would then be inserted in the system's software and then test flown over a period of about 10 hr for the purpose of evaluation

Identification of the Servomechanism used for micro-displacement

Friction causes important errors in the control of small servomechanism and should be determined with precision in order to increase the system performance. This paper describes the method to identify the model parameters of a small linear drive with ball-screw. Two kinds of friction models will be applied for the servomechanism looking to rise its micropositioning abilities. The first one includes the static, viscous and Stribeck friction with hysteresis, and the second one uses the Lugre model. The results will be compared taking into account the criterion error, the accuracy and the normalized mean-square-error of the identified mechanical parameters. The coefficients of the models are identified by a recursive identification method using data acquisition and special filtering technics. The least square identification method is used in this paper in order to establish the motor parameters used as initial condition of the recursive estimation method. Computer simulations and experimental results demonstrate the efficiency of the proposed model

Design of an electric drivetrain for the Formula Student-class vehicle

Hlavním úkolem této diplomové práce bylo navrhnout a postavit funkční prototyp frekvenčního měniče pro použití ve vozidlech týmu eForce FEE Prague Formula, soutěžícího v mezinárodní inženýrské soutěži Formula Student. Práce je členěna do několika kapitol, kdy je nejdříve prozkoumán již minule provedený vývoj v týmu. Dále je vystavěna potřebná teorie pro vývoj frekvenčního měniče. Další kapitola detailně popisuje provedený vývoj zařízení. Poslední kapitoly se věnují zhodnocení navrženého měniče. Diplomová práce také prozkoumala nové možnosti v měření fázových proudů, umožňující vysokou přesnost při zachování nízké ceny a kompaktních rozměrů. Celkovým cílem bylo navrhnout jednoduché a robustní zařízení s nízkou výrobní cenou. Ověřování návrhu bylo provedeno v laboratořích fakulty pro ujištění připravenosti navrženého měniče pro nasazení do vozidla. Práce bude pokračovat na vylepšování řídícího algoritmu a postupné integraci do týmových vozidel.This thesis' main objective was to design and develop a functional motor controller for usage in a Formula Student competition vehicle of the eForce FEE Prague Formula team. Work is split into several chapters. Exploring a drivetrain development progression in the team, presenting a needed theory for a motor controller development and giving a detailed overview of the designed device. The last chapters are dedicated to evaluation of the design. Thesis had explored a new methodology in a phase current sensing, providing a significant precision while allowing for a low cost and compact design. Overall aim was to create a simple, robust and cheap solution. Verification of the design was performed in the laboratory environment of the faculty in order to ensure preparedness for integration into the vehicle. Further work will focus on control strategy improvements and final integration into the team's vehicles

Design study of a low cost civil aviation GPS receiver system

A low cost Navstar receiver system for civil aviation applications was defined. User objectives and constraints were established. Alternative navigation processing design trades were evaluated. Receiver hardware was synthesized by comparing technology projections with various candidate system designs. A control display unit design was recommended as the result of field test experience with Phase I GPS sets and a review of special human factors for general aviation users. Areas requiring technology development to ensure a low cost Navstar Set in the 1985 timeframe were identified

Pointing control for the SPIDER balloon-borne telescope

We present the technology and control methods developed for the pointing system of the SPIDER experiment. SPIDER is a balloon-borne polarimeter designed to detect the imprint of primordial gravitational waves in the polarization of the Cosmic Microwave Background radiation. We describe the two main components of the telescope's azimuth drive: the reaction wheel and the motorized pivot. A 13 kHz PI control loop runs on a digital signal processor, with feedback from fibre optic rate gyroscopes. This system can control azimuthal speed with < 0.02 deg/s RMS error. To control elevation, SPIDER uses stepper-motor-driven linear actuators to rotate the cryostat, which houses the optical instruments, relative to the outer frame. With the velocity in each axis controlled in this way, higher-level control loops on the onboard flight computers can implement the pointing and scanning observation modes required for the experiment. We have accomplished the non-trivial task of scanning a 5000 lb payload sinusoidally in azimuth at a peak acceleration of 0.8 deg/s$^2$, and a peak speed of 6 deg/s. We can do so while reliably achieving sub-arcminute pointing control accuracy.Comment: 20 pages, 12 figures, Presented at SPIE Ground-based and Airborne Telescopes V, June 23, 2014. To be published in Proceedings of SPIE Volume 914

Project Echo: Antenna Steering System

The Project Echo communications experiment employed large, steerable,transmitting and receiving antennas at the ground terminals. It was necessary that these highly directional antennas be continuously and accurately pointed at the passing satellite. This paper describes a new type of special purpose data converter for directing narrow-beam communication antennas on the basis of predicted information. The system is capable of converting digital input data into real-time analog voltage commands with a dynamic accuracy of +/- 0.05 degree, which meets the requirements of the present antennas

Laboratory implementations of PMSM drive in hybrid electric vehicles applications

Field Programmable Gate Arrays (FPGAs) are one of the today\u27s most successful technologies for developing systems that require real time operation and providing additional flexibility to the designer. This research is focused on developing a control board for a permanent magnet synchronous machine (PMSM) using an FPGA module. The board is configured for individual use of an FPGA, digital signal processor (DSP) or in combination to control the PMSM by generating the required Pulse Width Modulator (PWM) to the inverter in order to drive and control the speed of the PMSM. Since, the exact rotor position and speed are required to control the motor; a useful method is developed digitally and implemented in the FPGA hardware module. The speed observer (SO), in which the Hall effect signals were used to calculate the speed and the angle of the rotor. In this thesis, three different techniques of PWM generation were developed and combined with rotor position and speed method. The project is implemented in Altera FPGA using Quartus II software V11.0 with VHDL as the supporting language. The design achieved high performance and accuracy of the detection estimation and control scheme for the Permanent Magnet Synchronous Machine. Error and design analysis has been done also --Abstract, page iii