Kirill V. Poletkin

A touch interface exploiting the use of vibration theories and infinite impulse response filter modeling based localization algorithm

Research into human-machine computer interface (HMI) has been very active in recent years due to the proliferation and advances in software applications. Such devices are aimed at providing a more natural interface for which humans and machines interact. In this multi-disciplinary research, we propose a new approach to the development of a touch interface through the use of surface mounted sensors which allow one to convert hard surfaces into touch pads. We first develop, using mechanical vibration theories, a mathematical model that simulates the output signals derived from sensors mounted on a physical surface such. Utilizing this model, we show that the profile of the output signals is unique not only in time but also in the frequency domain. We then exploit this important property to localize finger taps by developing a source localization algorithm based on infinite impulse response filter model for location template matching. The performance of the proposed algorithm is compared with existing approaches and verified both in a synthetic as well as a real environment for the localization of a finger tap on a touch interface.

Proposal for Micromachined Accelerometer, Based on a Contactless Suspension With Zero Spring Constant

In this paper, a micromachined accelerometer, based on a contactless suspension with a zero spring constant is proposed. The sensor provides the possibility of a significant increase in resolution. Minimization of the spring constant of the contactless suspension is achieved by combining inductive and electrical contactless suspensions. To study the conditions required to eliminate the spring constant of the suspension and achieve stable levitation of the accelerometer proof mass, a mathematical model of the suspension is developed. It is shown that such a suspension can be developed in principle.

Proposal for a Micromachined Dynamically Tuned Gyroscope, Based on a Contactless Suspension

In this paper, the operating principle of a micromachined, dynamically tuned gyroscope, based on a contactless suspension is discussed and its mathematical model is derived. Dynamical analysis based on this mathematical model for the case in which the contactless suspension provides “hard” electrical springs is conducted. The analysis shows that such a gyroscope can be created in principal and provides a value for the gyroscope gain to measuring angular rate which is several orders of magnitude greater in comparison with existed prototypes of the micromachined gyroscope based on a contactless suspension.

Source Localization in the Presence of Dispersion for Next Generation Touch Interface

We propose a new paradigm of touch interface that allows one to convert daily objects to a touch pad through the use of surface mounted sensors. To achieve a successful touch interface, localization of the finger tap is important. We present an inter-disciplinary approach to improve source localization on solids by means of a mathematical model. It utilizes mechanical vibration theories to simulate the output signals derived from sensors mounted on a physical surface. Utilizing this model, we provide an insight into how phase is distorted in vibrational waves within an aluminium plate which in turn serves as a motivation for our work. We then propose a source localization algorithm based on the phase information of the received signals. We verify the performance of our algorithm using both simulated and recorded data.

A New Hybrid Micromachined Contactless Suspension With Linear and Angular Positioning and Adjustable Dynamics

In this letter, we present a new hybrid micromachined contactless suspension based on combining electromagnetic inductive and electrostatic actuation. In addition, the stiffness components are dynamically adjusted during the operation phase using a series of electrodes integrated in the contactless suspension structure. We experimentally demonstrate vertical linear positioning of a disk-shaped proof mass in a range from 30 to 200 μm, controlled tilting about two orthogonal axes in the horizontal plane ranges from ±1° to ±4°, as well as controlled oscillation about the vertical axis with an angular displacement of 37° at a frequency of 1.5 Hz. In order to demonstrate dynamical adjustment of the stiffness, we experimentally show that the angular component of stiffness is increased by a factor of two at a levitation height of 100 μm. Therefore, the suspension dynamics can be changed and adapted to particular applications or to variations in operational environments. Moreover, we demonstrate that this device can operate as a bistable micro-actuator.

Performance Characterization of Micromachined Inductive Suspensions Based on 3D Wire-Bonded Microcoils

We present a comprehensive experimental investigation of a micromachined inductive suspension (MIS) based on 3D wire-bonded microcoils. A theoretical model has been developed to predict the levitation height of the disc-shaped proof mass (PM), which has good agreement with the experimental results. The 3D MIS consists of two coaxial wire-bonded coils, the inner coil being used for levitation, while the outer coil for the stabilization of the PM. The levitation behavior is mapped with respect to the input parameters of the excitation currents applied to the levitation and stabilization coil, respectively: amplitude and frequency. At the same time, the levitation is investigated with respect to various thickness values (12.5 to 50 μm) and two materials (Al and Cu) of the proof mass. An important characteristic of an MIS, which determines its suitability for various applications, such as, e.g., micro-motors, is the dynamics in the lateral direction. We experimentally study the lateral stabilization force acting on the PM as a function of the linear displacement. The analysis of this dependency allows us to define a transition between stable and unstable levitation behavior. From an energetic point of view, this transition corresponds to the local maximum of the MIS potential energy. 2D simulations of the potential energy help us predict the location of this maximum, which is proven to be in good agreement with the experiment. Additionally, we map the temperature distribution for the coils, as well as for the PM levitated at 120 μm, which confirms the significant reduction of the heat dissipation in the MIS based on 3D microcoils compared to the planar topology.

AN ANALYTICAL MODEL OF MICROMACHINED ELECTROMAGNETIC INDUCTIVE CONTACTLESS SUSPENSION

The paper presents an analytical model of a micromachined electromagnetic inductive contactless suspension, which describes the dynamics of a levitated disk shaped proof mass in space, near an equilibrium point. The proof mass is levitated in an electromagnetic field created by a ring shaped coil. The model derives from the analysis of the set of Lagrange - Maxwell equations obtained for the proof mass - coil system in a general form. Also the condition for the stable levitation of the proof mass in space is developed and expressed in terms of coefficients of the quadratic form of a function of mutual inductance between the disk shaped proof mass and ring shaped coil.

Polymer Magnetic Composite Core Boosts Performance of Three-Dimensional Micromachined Inductive Contactless Suspension

We introduce a newly developed polymer magnetic composite for use as a high resistivity, high permeability magnetic core to significantly improve the energy consumption of micromachined inductive suspensions. Compared to a similar inductive suspension structure without a core, the electrical current required to obtain a levitation height of 110 μm is 65 mA versus 120 mA. The use of the core brings the operating temperature in ambient air at 27 °C down from 120 °C to 60 °C, the lowest value among all previously reported micromachined inductive suspensions. Beyond this performance improvement, the present contribution demonstrates the feasibility of three-dimensional micromachined inductive suspensions as integrated elements of levitated micromachined systems.

Stable dynamics of micro-machined inductive contactless suspensions

In this article we present a qualitative approach to study the dynamics and stability of micro-machined inductive contactless suspensions (MIS). In the framework of this approach, the induced eddy current into a levitated micro-object is considered as a collection of m-eddy current circuits. Assuming small displacements and the quasi-static behavior of the levitated micro-object, a generalized model of MIS is obtained and represented as a set of six linear differential equations corresponding to six degrees of freedom in a rigid body by using the Lagrange-Maxwell formalism. The linear model allows us to investigate the general stability properties of MIS as a dynamic system, and these properties are synthesized in three major theorems. In particular we prove that the stable levitation in the MIS without damping is impossible. Based on the approach presented herewith, we give general guidelines for designing MIS. Additionally, we demonstrate the successful application of this technique to study the dynamics and stability of symmetric and axially symmetric MIS designs, both based on 3D micro-coil technology.

Static Behavior of Closed-Loop Micromachined Levitated Two-Axis Rate Gyroscope

In this paper, a model of Micromachined Levitated Gyroscope (MLG) with a closed-loop control is developed. The model provides a fundamental theoretical description of the operating principle of the MLG. Employing the obtained model, different operating modes of the MLG, which are depended on relationships between the speed of the rotor rotation, value of the stiffness provided by a contactless suspension and the rotor shape are considered. In particular, it is showed that decreasing the stiffness of the contactless suspension leads to two operating modes of the gyroscope, which are defined by the rotor shape. Moreover, an error model of the MLG for a closed loop is obtained, which allows us to give an explanation of the error-producing mechanics of the inherent errors of the MLG.