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Purpose This paper intends to lay a background knowledge towards the feasibility of developing a bottom-drive variable capacitance micromotor (VCM) using a surface micromachining process (SMP). The purpose of this paper is to determine the possibility of neglecting the bending of the rotor plates caused by the electrostatic normal forces when deploying a set of mechanical supports. Design/methodology/approach A multiphysics simulation approach is considered in order to analyse the coupled electromechanical effects in a steady state and to evaluate if the proposed geometries are useful to reduce the bending of the plates. Findings A surfaced micromachined bottom-drive VCM requires mechanical reinforcement in order to eliminate the risk of an electrical short circuit caused by the deformation in the rotor plates. The combination of an external supporting ring and anchored structural ribs on top of the rotor poles is sufficient to neglect the deformation in the poles of the rotor. Originality/value An original analysis with the objective of setting a background in the development of a bottom-drive electrostatic micromotor using a SMP is presented.

This paper presents the design of a biaxial capacitive accelerometer that takes advantages of a single-mass configuration to provide two orthogonal axes of sensitivity. The accelerometer structure is based on the SUMMiT V fabrication process. A set of fixed electrodes provides reliable measurements of capacitance in the two orthogonal directions. An analytical model based on the Euler-Bernoulli stress theory is introduced for variable cross-sectional area beams and is validated with a finite element analysis. In order to avoid a short circuit between fixed and movable electrodes, four displacement limiters were designed. The displacement limiters prevent out-of-plane displacement of the seismic mass and can withstand an impact of 250,000 G. A two-dimensional transient analysis of the seismic mass was carried out to confirm a linear oscillation behavior for either direction on the operation plane. The natural frequencies in the vibration modes of the two axes of interest are 462.5 and 463.2 Hz. It is also shown that the principal stresses in the beams are smaller than the fracture strength of polysilicon.

In this paper we describe the mechanical and electronic design of KAY JUUL, an academic underwater glider, we also show the results from experimental tests developed in a pool. A Sliding PD Control scheme have been applied in the system, due to we don't know the parameters of the KAY JUUL yet, the control output variables were selected based on simulation results and theoretical analysis of the ROGUE, an academic glider developed by Princeton University. Satisfactory results were expected, have been achieved and are presented here.

This paper describes a novel method for on-line real-time data reduction of radiofrequency (RF) ultrasound signals. The approach is based on a field programmable gate array (FPGA) system intended mainly for steel thickness measurements. Ultrasound data reduction is desirable when: (1) direct measurements performed by an operator are not accessible; (2) it is required to store a considerable amount of data; (3) the application requires measuring at very high speeds; and (4) the physical space for the embedded hardware is limited. All the aforementioned scenarios can be present in applications such as pipeline inspection where data reduction is traditionally performed on-line using pipeline inspection gauges (PIG). The method proposed in this work consists of identifying and storing in real-time only the time of occurrence (TOO) and the maximum amplitude of each echo present in a given RF ultrasound signal. The method is tested with a dedicated immersion system where a significant data reduction with an average of 96.5% is achieved.

The response of the ROGUE underwater glider controlled by a scheme called Sliding PD control is shown and described. This control law has been widely used in robot manipulators, quadrotors and underwater ROV's. This is a model-free and chattering-free controller that makes motion robust to disturbance and uncertainty. The ROGUE dynamic model calculated on the vertical plane take into account a ballast tank fixed at the buoyancy center, a movable mass capable of motion just along the longitudinal axis and eliminates the offset static point mass. These considerations simplify significantly the equations of motion. Through simulation results this nonlinear controller demonstrates that it ensures a steady glide by directly controlling the movable mass position along with the ballast mass.

Underwater remotely operated vehicles (ROVs) play an important role in a number of shallow and deep-water missions for marine science, oil and gas extraction, exploration and salvage. In these applications, the motions of the ROV are guided either by a human pilot on a surface support vessel through an umbilical cord providing power and telemetry, or by an automatic pilot. In the case of automatic control, ROV state feedback is provided by acoustic and inertial sensors and this state information, along with a controller strategy, is used to perform several tasks such as station-keeping and auto-immersion/heading, among others. In this paper, the modelling, design and control of the Kaxan ROV is presented: i) The complete six degrees of freedom, non linear hydrodynamic model with its parameters, ii) the Kaxan hardware/software architecture, iii) numerical simulations in Matlab/Simulink platform of a model-free second order sliding mode control along with ocean currents as disturbances and thruster dynamics, iv) a virtual environment to visualize the motion of the Kaxan ROV and v) experimental results of a one degree of freedom underwater system.

A New Adaptive Self-Tuning Fourier Coefficients Algorithm for Periodic Torque Ripple Minimization in Permanent Magnet Synchronous Motors (PMSM) Torque ripple occurs in Permanent Magnet Synchronous Motors (PMSMs) due to the non-sinusoidal flux density distribution around the air-gap and variable magnetic reluctance of the air-gap due to the stator slots distribution. These torque ripples change periodically with rotor position and are apparent as speed variations, which degrade the PMSM drive performance, particularly at low speeds, because of low inertial filtering. In this paper, a new self-tuning algorithm is developed for determining the Fourier Series Controller coefficients with the aim of reducing the torque ripple in a PMSM, thus allowing for a smoother operation. This algorithm adjusts the controller parameters based on the component’s harmonic distortion in time domain of the compensation signal. Experimental evaluation is performed on a DSP-controlled PMSM evaluation platform. Test results obtained validate the effectiveness of the proposed self-tuning algorithm, with the Fourier series expansion scheme, in reducing the torque ripple.

Bilateral teleoperation systems have attracted significant attention in the last decade mainly because of technological advancements in both the communication channel and computers performance. In addition, non-linear multi-degree-of-freedom bilateral teleoperators along with state observers have become an open research area. In this article, a model-free exact differentiator is used to estimate the full state along with a chattering-free second-order sliding mode controller to guarantee a robust impedance tracking under both constant and an unknown time delay of non-linear multi-degree-of-freedom robots. The robustness of the proposed controller is improved by introducing a change of coordinates in terms of a new nominal reference similar to that used in adaptive control theory. Experimental results that validate the predicted behaviour are presented and discussed using a Phantom Premium 1.0 as the master robot and a Catalyst-5 virtual model as the slave robot. The dynamics of the Catalyst-5 system is solved online.

This paper describes both the design and technical integration of a deep water ROV (Remotely Operated Vehicle) that is able to employ visual inspection in deep water, as well as to take samples with an underwater arm. Visual inspection is the essential application for a ROV, which is useful for; underwater structure inspection, underwater oil production systems inspection and underwater pipeline inspection. This paper mainly describes the ROV design, and explains in general manner other elements; such as the SCU, LARS and TMS. It is important to mention that the design phase is complete and it was financed by PEMEX (Federal Mexican Oil Company). The project has stalled, since we are waiting for the financial support from PEMEX for the system construction. A future objective is the design and construction of Work-Class ROVs, which can be used to perform PEMEX specific tasks.

This paper describes the platform for a bilateral teleoperation where the master is a haptic device and the slave is a commercial small-sized underwater vehicle. The submarine will be instrumented, so that the electronics architecture can be upgrade at any time. With this new architecture it will be possible to program any advanced control scheme an the embedded. Also, position and velocity commands from the haptic interface to the small-sized underwater vehicle, will be send. Such that, when the force sensor, placed in the nose of the underwater vehicle, interacts with the environment, it will measure the force at the slave site and feed back it to the master robot.

Esta tesis presenta el diseño, modelado analítico y simulación de un micromotor electrostático basado en tecnología MEMS. Los micromotores electristáticos existentes conllevan obstáculos que son inherentes a su geometría o proceso de fabricación, en algunos de ellos la potencia generada no es suficiente para poder ser aprovechada, otros son inestables o su proceso de fabricación es demasiado complejo. En cambio, la geometría propuesta es capaz de generar un nivel de fuerza electróstatica utilizable en microsistemas y además, no es necesarion ningún tipo de ensamble o postproceso para obtener un prototipo estable.

En esta tesis se presenta el diseño de una arquitectura VLSI de algoritmo filtro kalman convencional con la formulación secuencial y la estabilizada de Joseph para aplicaciones de navegación inercial, optimizada en área de silicio y consumo de energía.