Tuna Balkan

An Electromagnetic Micro Power Generator for Low-Frequency Environmental Vibrations Based on the Frequency Upconversion Technique

This paper presents a microelectromechanical-system-based electromagnetic vibration-to-electrical power generator that can harvest energy from low-frequency external vibrations. The efficiency of vibration-based harvesters is proportional to excitation frequency, so the proposed generator is designed to convert low-frequency environmental vibrations to a higher frequency by employing the frequency upconversion (FupC) technique. It has been shown that the generator can effectively harvest energy from environmental vibrations of 70-150 Hz and generates 0.57-mV voltage with 0.25-nW power from a single cantilever by upconverting the input vibration frequency of 95 Hz-2 kHz. The fabricated generator size is 8.5×7×2.5 mm3, and a total of 20 serially connected cantilevers have been used to multiply the generated voltage and power. The generator demonstrated in this paper is designed for the proof of concept, and the power and voltage levels can further be increased by increasing the number of cantilevers or coil turns. The performance of the generator is also compared with that of a same sized custom-made traditional magnet-coil-type generator and with that of a traditional generator from the literature to prove its effectiveness.

An electromagnetic micro energy harvester based on an array of parylene cantilevers

This paper presents the design, optimization and implementation of an electromagnetic type vibration-to-electrical micro energy harvester. The proposed harvester implements a new design employing array of parylene cantilevers on which planar gold coils are fabricated. The micro harvester generates voltage by virtue of the relative motion between the coils and a stationary magnet. The coils are connected electrically in series to sum up the voltage output from individual cantilevers. The number of cantilevers can be adjusted to improve the generated power without significantly increasing the overall device volume. Another forthcoming feature of this study is the investigation of the phase-shift phenomenon, which is the effect of natural frequency mismatches between the cantilevers due to fabrication related nonuniformities. A detailed mathematical modeling and optimization of the design for various cases, together with the phase and frequency shifts between the cantilevers, are carried out. The proposed harvester is implemented on a microscale and mathematical modeling is verified through extensive tests. The fabricated device occupies a volume of 9.5 × 8 × 6 mm3. A single cantilever of this device can generate a maximum voltage and power of 0.67 mV and 56 pW, respectively, at a vibration frequency of 3.4 kHz. These values can be improved considerably by increasing the coil turns and natural frequency of the cantilevers. However, our test results show that any mismatch between the series cantilevers results in significant degradation of the overall output.

An Electromagnetic Micro Power Generator for Low Frequency Environmental Vibrations based on the Frequency Up-Conversion Technique

This paper presents an electromagnetic (EM) vibration-to-electrical power generator, which can efficiently harvest energy from low-frequency external vibrations by using frequency up-conversion. The generator can effectively scavenge energy from low frequency environmental vibrations of 70-150 Hz and generates 0.57 mV voltage with 0.25 nW power from a single cantilever at a vibration frequency of 95 Hz. The fabricated generator size is 8.5 × 7 × 2.5 mm3 and a total number of 20 serially connected cantilevers have been used to multiply the generated voltage and power. The performance of the generator is also compared with a same sized traditional magnet-coil type generator to prove its effectiveness.

A Wideband Electromagnetic Micro Power Generator for Wireless Microsystems

This paper presents a wideband electromagnetic (EM) vibration-to-electrical power generator which can efficiently scavenge energy and generate steady power over a predetermined frequency range. Power is generated by means of electromagnetic induction using a magnet and coils on top of resonating cantilever beams. The reported generator covers a wide band of external vibration frequency by implementing a number of serially connected cantilevers in different lengths. The device generates 0.5 muW continuous power with 20 mV voltage between 3.3 and 3.6 kHz of external vibration.

A kinematic structure-based classification and compact kinematic equations for six-dof industrial robotic manipulators

Abstract A kinematic structure-based classification of six degree-of-freedom industrial robotic manipulators is introduced, and a complete set of compact kinematic equations is given according to this classification. For the classification, 100 industrial robots are surveyed. These robots are first classified into main groups and then into subgroups under each main group, and nine kinematic main groups, each having 1–10 subgroups are obtained. The main groups are based on the end-effector rotation matrices and characterized by the twist angles. On the other hand, the subgroups are based on the wrist point positions and characterized by the link lengths and offsets. Compact kinematic equations are derived for all main groups and subgroups by utilizing the properties of exponential rotation matrices, and simplification tools derived by using these properties. Most of these simplified compact equations can be solved analytically and the remaining few of them can be solved semi-analytically through a single univariate equation. In these solutions, the singularities and the multiple configurations of the manipulators can be determined easily. Using these solutions, the inverse kinematics can also be computerized by means of short and fast algorithms.

A method of inverse kinematics solution including singular and multiple configurations for a class of robotic manipulators

A semi-analytical method and an associated computer program are developed for inverse kinematics solution of a class of robotic manipulators, in which four joint variables are contained in the wrist point equations. For this case, it becomes possible to express all the other joint variables in terms of a selected one, and this reduces the inverse kinematics problem to solving a non-linear scalar equation having the selected joint variable as the only unknown. The solution can be obtained by iterative methods and the remaining joint variables can easily be computed by using the solved joint variable. Since the method is manipulator dependent, the equations will be different for kinematically different classes of manipulators, and should be obtained analytically in a similar way as done here, using the suggested algebra based on exponential rotation matrices. A significant benefit of the method is that the singular configurations and multiple solutions indicated by sign ambiguities can be determined while deriving the inverse kinematic expressions. The developed method is applied to a six-revolute-joint industrial robot, FANUC Arc Mate Sr.

Multisensor controlled robotic tracking and automatic pick and place

A multisensor controlled robotic tracking and automatic pick and place system is presented in this paper. The system is designed for recognizing and tracking an object which is selected from multiple objects that are unknown and randomly placed on a moving conveyor belt, using a vision, infrared and encoder sensors in the feedback loop. The robot tracks the parts and transfers them to the proper pallets. We address the use of vision system for identifying and locating objects on a moving conveyor belt, besides we address the use of vision, infrared and encoder sensors for dynamically servoing a manipulator for object tracking, grasping and placing. Laboratory experiments are presented to demonstrate the performance of this system.

A micro power generator with planar coils on parylene cantilevers

In this paper an electromagnetic vibration based micro power generator is presented. The proposed generator is composed of parylene cantilevers on which planar coils are fabricated. The system uses external vibrations to generate power by virtue of the relative motion between the cantilevers and a magnet. The parameters of the micro generator have been optimized for maximum output and it has been fabricated in micro scale. Initials tests show that 8.75 mV could be obtained from the proposed generator at a vibration frequency of 5.1 kHz.

Process Simulation and Paint Thickness Measurement for Robotic Spray Painting

Abstract A method and a computer program are developed for modeling of spray painting process, simulation of robotic spray painting, off-line programming of industrial robots and paint thickness measurement for painting of curved surfaces. The computer program enables the user to determine the painting strategies, parameters and paths. Surface models of the parts that are to be painted are obtained by using a CAD software. For paint thickness measurements, probe of the coating thickness measurement gage is attached to the wrist of the robot by using a feedback/safety adapter designed and manufactured for this purpose. Thicknesses are measured and transferred to the computer automatically. Then, obtained thickness data is processed and comparisons between simulated and measured thicknesses are made.

A Complete Analysis and a Novel Solution for Instability in Pump Controlled Asymmetric Actuators

This paper addresses the stability problem of pump controlled asymmetric hydraulic actuators and proposes a physical solution for it. The system under consideration utilizes a shuttle valve to compensate for unequal flow rates due to the asymmetry in the actuator. Possible hydraulic circuit configurations resulting from various valve positions are defined on the load pressure versus velocity plane and a generalized linear model of the system is derived. The investigation shows that there exists a critical load pressure region in which any equilibrium point requiring a partially open spool position is unstable during the retraction of the actuator. A particular valve underlap is proposed in order to avoid the instability and a shuttle valve selection guide is presented. Theoretical findings are validated by both numerical simulations and experimental tests. Results show that the undesired pressure oscillations are removed up to certain actuator velocities with the use of an underlapped shuttle valve.