This paper proposes a new flash time-to-digital converter (TDC) design, which incorporates deterministic, variable delay into the decision elements. These are implemented with cross-coupled NAND standard cells of variable transistor widths. Both experiment and simulation are used to validate this new design, which provides variable time-difference ranges by controlling the input slew rate. It is also possible to use the proposed flash TDC as a soft macro.

This paper demonstrates a new technique to reduce the comparator delay dispersion caused by variable input overdrive. In the proposed technique, the conventional comparator circuit is modified by adding a variable driving-current block (VDCB) which is used such that it supplies the output node of the differential amplifier with a current that is inversely proportional with the level of input signal. Therefore the overdrive- caused delay dispersion is effectively reduced. The technique incurs small area overhead (only three transistors) compared with the previous works. The proposed circuit is implemented in 45nm technology. The effect of process variation on the performance of the proposed technique is studied by simulation. The results show that the overdrive-related propagation delay dispersion of the proposed technique is 26% of its counterpart in the conventional comparator for an input frequency up to 500MHz. The power consumption is 220 μW at 200MHz.

Compliance detection becomes very essential inminimally invasive surgery (MIS). It can help in detection of cancerous lumps and/or for deciding on tissue healthiness. In this paper, a micromachined piezoresistive tactile sensor, with two serpentine springs and 500-μm cubic mesas, has been designed for detecting the compliance of soft tissue independent of the applied distance between the sensor and the tissue. The measuring range of the sensor is chosen to be associated with the soft-tissue properties. The sensor parameters are optimized to give high sensitivity and linearity of the sensor output. The design is simulated using ANSYS for checking the sensor performance. Then, the sensor is fabricated and tested by three types of specimens, namely, specimen chips with known stiffness, silicone rubber specimens, and chicken organ specimens (leg and heart). For the specimen chips and silicone rubber specimens, the sensor distinguished between different stiffnesses independent of the applied displacement in the range of 50–200 μm. The sensor measured Young’s modulus up to 808 kPa with an average error of±7.25%. For the chicken leg and heart, the sensor distinguished between them under the applied displacement from 100 to 200 μm, and they were calculated as 12 ± 1 kPa and 81 ± 8 kPa, respectively.

Compliance detection becomes very essential inminimally invasive surgery (MIS). It can help in detection of cancerous lumps and/or for deciding on tissue healthiness. In this paper, a micromachined piezoresistive tactile sensor, with two serpentine springs and 500-μm cubic mesas, has been designed for detecting the compliance of soft tissue independent of the applied distance between the sensor and the tissue. The measuring range of the sensor is chosen to be associated with the soft-tissue properties. The sensor parameters are optimized to give high sensitivity and linearity of the sensor output. The design is simulated using ANSYS for checking the sensor performance. Then, the sensor is fabricated and tested by three types of specimens, namely, specimen chips with known stiffness, silicone rubber specimens, and chicken organ specimens (leg and heart). For the specimen chips and silicone rubber specimens, the sensor distinguished between different stiffnesses independent of the applied displacement in the range of 50–200 μm. The sensor measured Young’s modulus up to 808 kPa with an average error of±7.25%. For the chicken leg and heart, the sensor distinguished between them under the applied displacement from 100 to 200 μm, and they were calculated as 12 ± 1 kPa and 81 ± 8 kPa, respectively.

Compliance detection becomes very essential inminimally invasive surgery (MIS). It can help in detection of cancerous lumps and/or for deciding on tissue healthiness. In this paper, a micromachined piezoresistive tactile sensor, with two serpentine springs and 500-μm cubic mesas, has been designed for detecting the compliance of soft tissue independent of the applied distance between the sensor and the tissue. The measuring range of the sensor is chosen to be associated with the soft-tissue properties. The sensor parameters are optimized to give high sensitivity and linearity of the sensor output. The design is simulated using ANSYS for checking the sensor performance. Then, the sensor is fabricated and tested by three types of specimens, namely, specimen chips with known stiffness, silicone rubber specimens, and chicken organ specimens (leg and heart). For the specimen chips and silicone rubber specimens, the sensor distinguished between different stiffnesses independent of the applied displacement in the range of 50–200 μm. The sensor measured Young’s modulus up to 808 kPa with an average error of±7.25%. For the chicken leg and heart, the sensor distinguished between them under the applied displacement from 100 to 200 μm, and they were calculated as 12 ± 1 kPa and 81 ± 8 kPa, respectively.

This study investigates an application of the fuzzy logic technique for designing the load-frequency control system to damp the frequency and tie line power oscillations due to different load disturbances under the governor deadzones and GRC non-linearity. Integral controller are designed and compared with the proposed fuzzy logic controller. To validate the effectiveness of the proposed controller, two-area load frequency power system is simulated over a wide range of operating conditions and system parameter changes. Further, comparative studies between the conventional PID control and proposed efficient fuzzy logic load frequency control are included on the simulation results. Programs Matlab software are developed for simulation. The digital results prove the power of the present fuzzy load-frequency controller over the conventional. PID controller in terms of fast response with less overshoot and small settling time.

The aim of study is designed of Power System Stabilizer (PSS) based on H4 approach for power system stabilization. The uncertainties in power system modeling and operations are considered at designing of H4 PSS. The bounds of power system parameters are determined over a wide range of low frequency operating conditions. These bounds are used to design a robust H4 PSS. A sample power system composed a synchronous generator connected to infinite bus through transmission line is simulated. The digital H4 PSS can achieve good performance over a wide range of operating conditions. A comparison between power system responses at variety of operating conditions using the proposed H4 PSS and Linear Quadratic Regulator LQR control have been done. H2 PSS is designed and compared with the proposed controller.

A position control of DC motor servo drive based on the Sliding Mode (SM) approach is presented. The modeling and analysis of the servo DC motor are obtained. The Sliding Mode Controller (SMC) design changes such that its performance is substantially improved. To improve the controller performance in steady stat (zero error) the Integral Sliding Mode Controller (ISMC) is used. Since the main drawback of SMC is a phenomenon, the so-called chattering, resulting from discontinuous controllers. A ISMC with switched gains is used for chattering reduction and controller robustness. For comparison, the proposed ISM with switched gains is compared with that of a PID controller. Experiments and simulations have been carried out in order to validate the effectiveness of the proposed scheme. The proposed controller offers very good tracking; it is highly robust, reaches the final position very fast. Furthermore the application of the SM ensures reduction of the system order by one. Also, quick recovery from matched disturbance in addition to good tracking ability. Moreover, this scheme is robust against the parameters variations and eliminate the influence of modeling.