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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

On the use of generalized force data for kinematically controlled manipulators

Schroeder, Kyle Anthony 16 February 2011 (has links)
The Department of Energy national laboratories, like Los Alamos National Lab or Sandia National Lab, perform work on radioactive and chemically dangerous materials. Gloveboxes are often used to shield workers from these hazards, but they cannot completely eliminate the danger and often create new safety concerns due to reduced operator dexterity and ergonomic posture. When feasible, robots can be employed to remove the human from the radioactive hazard; allowing them to analyze the situation and make decisions remotely. Force sensor data from the manipulator can be used to simplify the control of these remote systems as well as make them more robust. Much research has been done to develop force and torque control algorithms to introduce compliance or detect collisions. Many of these algorithms are very complicated and currently only implemented in research institutions on torque-controlled manipulators. The literature review discusses many such controllers which have been developed and/or demonstrated. This thesis reviews, develops, and demonstrates several beneficial algorithms which can be implemented on commercially-available kinematically-controlled robots using commercially-available sensors with a reasonable investment of time. Force data is used to improve safety and manage contact forces while kinematically controlling the robot, as well as improve the world model. Safety is improved by detecting anomalous and/or excessive forces during operation. Environmental modeling data is inferred from position and/or force data. A six-axis sensor and joint torque sensors on 2 7DOF manipulators are used to demonstrate the proposed algorithms in two DOE relevant applications: remotely opening an incompletely modeled cabinet door and moving a robot in a confined space. / text
2

Actuator control using pre-calibrated force data on a quadrocopter

Lafih, Amil January 2013 (has links)
In flying robots, stability control is often very sensitive to the actuator performances, and the software module performing the controller, is usually subjected to a long and difficult tuning phase strongly dependent on the specific actuator used. The actuators are often electric motors equipped with propellers. The motor and propeller combination performs differently for every choice of components adopted, even if they are provided by the same vendor with the same part family. The project aims to develop an intelligent actuator module for flying robots composed by a BLDC motor and a propeller, which is invariant to the specific motor and propeller adopted. By gathering the force data of the four used on a quadrocopter, the force and control signal relation could be defined and stored into the program memory of the control board. A battery monitor and a Force-PWM controller was implemented such that it takes force as input and outputs the desired PWM-signal. Tests were made on a prototype of Iqarus quadrocopter and by mounting it with ropes to the floor, it was tested on the lift-off phase. The experiment showed theoretical and practical results, which concludes that the quadrocopter maintained the ability to lift right upwards without any remaining control, assuming proper weight balance of the quadrocopter. / Inom flygande robotar, är stabilitet kontrollen oerhört känsligt till styrdonets prestation, och mjukvaru modulen som utför kontrollen, är ofta förknippad med en lång och problematisk justerings fas starkt beroende av de enskilda styrdonen. Styrdonen är ofta elektriska motorer med propeller. Motor och propeller kombinationen uppträder olika för varje val av komponent, även om komponenterna är försedda från samma återförsäljare och modell. Syftet med detta projekt är att utveckla en intelligent styrdons modul för flygande robotar, omfattad av en BLDC motor och propeller, som blir oberoende av den särskilda motor och propeller kombination som används. Genom att samla kraft data för de fyra styrdonen som används på en quadrocopter, kunde relationen mellan kraft och kontroll signal bli definierad och lagrad i program minnet för kontrol kortet. En batteri monitor och en Kraft-PWM kontroller implementerades, vilket tar kraft data som ingång och skickar ut motsvarande PWM-signal som utgång. Tester var gjorda med en prototyp av Iqarus quadrocopter och genom att binda fast den med rep till golvet, testades den för upplyfts fasen. Experimenten visade teoretiska och praktiska resultat, vilket visar att quadrocoptern bevarade förmågan att lyfta rakt uppåt utan någon övrig kontroll, förutsatt ordentlig vikt balans av quadrocoptern. / <p>Hejsan,</p><p>Detta ar den nya versionen, som ska ersatta den gamla versionen som blev uppladdad 6/11-13.</p><p>Tack,</p><p></p><p>Mvh</p><p>Amil Lafih</p>

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