Showing papers by "V. Jagadeesh Kumar published in 2019"

A Linear Differential Inductive Displacement Sensor With Dual Planar Coils

Abstract: A non-contact displacement sensor employing a couple of planar coils etched on printed circuit boards (PCBs) and an E-type soft ferromagnetic core is proposed here. The E-type soft ferromagnetic core moves over two triangular shaped spiral coils etched on a couple of PCBs. The variation in the inductances of the two coils has a cubic polynomial relationship with the displacement of the core. An appropriate signal conditioning technique operates on the inductances and provides an output that varies linearly with the displacement. The symmetrical structure of the sensor provides negligible cross axis sensitivity. Simulation studies and results obtained from a prototype sensor having a 70-mm range and a resolution of $2~\mu \text{m}$ , built and tested, establish the efficacy of the proposed technique. The worst-case nonlinearity observed from the prototype is 0.4%.

A Capacitive-Coupled Noncontact Probe for the Measurement of Conductivity of Liquids

Abstract: A noncontact (capacitive-coupled) probe for the measurement of the conductivity of liquids is presented. Insulation introduced between the measurement electrodes and the liquid intrudes a couple of coupling capacitances. Though the capacitive coupling overcomes the problems of electrode polarization and contamination associated with contacting electrodes, the large reactances of the coupling capacitors pose a problem in the measurement of comparatively very small resistance of the liquid. An auto-balancing signal conditioning scheme presented here overcomes the problem posed by the large capacitive reactances and provides directly a measurable output proportional only to the conductance of the liquid. Error analysis of the probe presented herein helps the optimal design of the probe. A worst case error of ± 0.9% was obtained from a prototype noncontact conductivity probe, developed and tested.

Conductivity Measurement Using Non-Contact Potential Electrodes and a Guard Ring

Abstract: This paper presents an improved method for the measurement of the conductivity of a liquid. In the proffered technique, the contact-type potential terminals of a traditional four lead conductivity probe are replaced with non-contacting terminals thus preventing electrode corrosion and contamination affecting the conductivity measurement. An additional guard electrode introduced in the present design ensures that the current through the external/surrounding medium becomes negligible thus reducing the error due to current flow, external to the probe. A self-balancing signal conditioning circuit, specially designed to suit the probe, alleviates the new problems of the modified probe. Simulation results and the results obtained from a prototype built and tested establish the efficacy of the proposed technique. The worst case error was found to be ± 0.78% with the prototype probe.

Embedded System Design for Autonomous Unmanned Surface Vehicles in Laboratory Environment

Abstract: Sea-keeping, maneuvering, and motion tests of surface vehicle/ship model need self-propelled scale model which can perform different maneuvers. The present work describes the design implementation and testing of embedded system of an autonomous system for unmanned surface vehicles (USVs)/ship model in the laboratory environment. This is a first-time national development test in the wave basin has demonstrated full-free running self-controlled model in a disturbance environment. The central unit of the system is an embedded controller, compact reconfigurable input–output (cRIO) which features a field-programmable gate array (FPGA) and a processor running Linux-based real-time operating system. It performs the main propulsion control, rudder control data logging and telemetry. The peripherals are interfaced with main controller through multifunction input–output module. The RS-232 communication is used to interface the MRU sensor with main controller. LabVIEW is used as programming tool to develop a program to control the peripherals connected to the main controller and data acquisition over a wireless link using Wi-Fi. A graphical user interface is developed to send control commands and visualize the 4-degree of motion at base station in real time.

Inductive-Capacitive Coupled Probe for Non-Contact Measurement of Liquid Conductivity

Abstract: This paper presents a non-contact inductive and capacitive coupled method of measurement of conductivity of liquids. The current through a pre-set column of liquid is established through induction. The voltage drop across the preset column of liquid is measured through capacitive coupled electrodes. The absence of contacting electrodes ensures that the method is free from effects due to contamination / corrosion of electrodes. The method proposed ensures that the measurement of the voltage drop across the column is independent of the values of the coupling capacitances of the capacitive coupled electrode. Hence, any deviation in the fabrication of the probe has negligible influence on the measured conductivity. Results obtained from a prototype unit built and tested show that the maximum relative error in the conductivity measurement is $ and the measured conductivity values are independent of the values of the coupling capacitors.