Design of a Solar Panel Deployment and Tracking System for Pocketqube Pico-Satellite

Modularized small satellites will have even greater potential with better energy supply. In this paper, a PocketQube solar panel deployment and tracking system will be presented. The system is designed for a 3P PocketQubes. During the designing phase, trade-off analysis is done to meet the balance of weight, dimension and efficiency. Reliability, manufacturability, and cost are also considered from the beginning, as commercial production and launch are expected. The CAD design, dynamics analysis, motion simulation, and rendering for the project are undertaken by Solidworks, whereas Abaqus CAE is utilized for the finite element analysis of the vibration test of the panels. In the gimbal subsystem, we use two micro stepper motor to drive the panels via a two-axis gearbox, enabling the panels to track the sun omnidirectionally. In the panel subsystem, two types of customized spring hinges are designed. Robust and verified parts, such as burner resistors, are chose for the control and deployment system. After the continuous optimization process throughout the design phase, by comparing different manufacturing processes technologies, materials, and design details, the full scale prototypes of the gimbal subsystem were built and tested. In the end, the most feasible solution, as well as the suggestions for the development, were put forward

Proceedings of the 4th field robot event 2006, Stuttgart/Hohenheim, Germany, 23-24th June 2006

Zeer uitgebreid verslag van het 4e Fieldrobotevent, dat gehouden werd op 23 en 24 juni 2006 in Stuttgart/Hohenhei

The influence of piezoceramic stack location on nonlinear behavior of langevin transducers

Power ultrasonic applications such as cutting, welding, and sonochemistry often use Langevin transducers to generate power ultrasound. Traditionally, it has been proposed that the piezoceramic stack of a Langevin transducer should be located in the nodal plane of the longitudinal mode of vibration, ensuring that the piezoceramic elements are positioned under a uniform stress during transducer operation, maximizing element efficiency and minimizing piezoceramic aging. However, this general design rule is often partially broken during the design phase if features such as a support flange or multiple piezoceramic stacks are incorporated into the transducer architecture. Meanwhile, it has also been well documented in the literature that power ultrasonic devices driven at high excitation levels exhibit nonlinear behaviors similar to those observed in Duffing-type systems, such as resonant frequency shifts, the jump phenomenon, and hysteretic regions. This study investigates three Langevin transducers with different piezoceramic stack locations by characterizing their linear and nonlinear vibrational responses to understand how the stack location influences nonlinear behavior

Encoderless position estimation and error correction techniques for miniature mobile robots

This paper presents an encoderless position estimation technique for miniature-sized mobile robots. Odometry techniques, which are based on the hardware components, are commonly used for calculating the geometric location of mobile robots. Therefore, the robot must be equipped with an appropriate sensor to measure the motion. However, due to the hardware limitations of some robots, employing extra hardware is impossible. On the other hand, in swarm robotic research, which uses a large number of mobile robots, equipping the robots with motion sensors might be costly. In this study, the trajectory of the robot is divided into several small displacements over short spans of time. Therefore, the position of the robot is calculated within a short period, using the speed equations of the robot's wheel. In addition, an error correction function is proposed that estimates the errors of the motion using a current monitoring technique. The experiments illustrate the feasibility of the proposed position estimation and error correction techniques to be used in miniature-sized mobile robots without requiring an additional sensor

Magnetostrictive direct drive motor

Highly magnetostrictive materials such as Tb.3Dy.7Fe2, commercially known as TERFENOL-D, have been used to date in a variety of devices such as high power actuators and linear motors. The larger magnetostriction available in twinned single crystal TERFENOL-D, approx. 2000 ppm at moderate magnetic field strengths, makes possible a new generation of magnetomechanical devices. NASA researchers are studying the potential of this material as the basis for a direct microstepping rotary motor with torque densities on the order of industrial hydraulics and five times greater than that of the most efficient, high power electric motors. Such a motor would be a micro-radian stepper, capable of precision movements and self-braking in the power-off state. Innovative mechanical engineering techniques are juxtaposed on proper magnetic circuit design to reduce losses in structural flexures, inertias, thermal expansions, eddy currents, and magneto-mechanical coupling, thus optimizing motor performance and efficiency. Mathematical models are presented, including magnetic, structural, and both linear and nonlinear dynamic calculations and simulations. In addition, test results on prototypes are presented

Optimisation of the longitudinal-torsional output of a half-wavelength Langevin transducer

Numerous ultrasonic applications, such as high-frequency/low frequency drilling, require or can benefit from the inclusion of some torsional vibration behaviour within a primarily longitudinal pattern. Producing longitudinal-torsional (LT) vibration in a Langevin transducer using the mode degeneration method tends to give more robust results than the competing mode-coupling approach, and this work is concerned with optimizing the relative strengths of the longitudinal and torsional responses within the context of a half-wavelength Langevin transducer. Using numerical and experimental techniques, the output of such a system is predicted across a range of geometries and compared to experimental results obtained through laser vibrometry