This paper presents a novel architecture of Femto power-delay super threshold voltage level shifter for network on chip voltage control, and developed using feedback topology for error aware interconnections data transmission. The proposed Level Shifter (LS) utilize eight MOS transistors with low aspect ratios for level up or level down. The developed LS can able to shift as low as 0.12 V to 1.25 V with tremendously reduction in delay and power consumptions. Implemented in 65 nm CMOS technology and the post-layout simulation substantiate the achievement of voltage translation. The proposed LS incurs energy per cycle 44 fJ during up shift, average level up and level down static power consumption is of 3.61 nW while VDDL is 0.3 V and VDDH is 1.2 V at the frequency of 1 MHz. The layout area of the proposed LS is 3.21 µm × 2.13 µm.

In solar tracking system, general stepper motor is used to control the stepwise movement and low speed of solar panel in vertical motion. Degree of rotation is directly proportional to stepwise movement (stepping method) of stepper motor. But it is cumbersome process to hold a solar panel at a particular vertical position depending on the sun’s position using low cost stepper motors. So, geared DC motor is implemented into stepper motor for low-speed applications using Stepping Method (GDCSM). Degree per step movement of geared DC motor is identified using Step angle switching delay time signal (A) of microcontroller. Speed of geared DC motor is controlled by passing fixed time interval between the pulses where the pulses have fixed width. Controlling speed is implemented by using Step delay time signal (D) of microcontroller. Combining effect of switching delay time signals A and D represents the Stepping Method. Stepping method resembles the step movement and controlling speed of the stepper motor. Speed of 10RPM & 30RPM geared DC motors is operated at 10V DC power supply. Microcontroller ATmega 328P with switching delay time signals is used to control the geared DC motors. Performance of 10RPM & 30RPM GDCSM is analyzed with stepper motors in terms of Relative slip degree error per revolution (RE $$_\mathrm{{S}}$$S ) and acceptable slippage degree tolerance under open loop condition. Change in consuming voltage tolerance ( $$\varDelta$$Δ ) during rotation of GDCSM is another parameter which is used to maintain the constant actual total step count per revolutions of GDCSM. At 40 ms of step angle delay time (A), 10RPMGDCSM has 120 steps per revolution. At 25 ms of A, 30RPMGDCSM has 55 steps per revolution. Speed of 10RPM & 30RPM GDCSM is controllable up to 2RPM when its RE $$_\mathrm{{S}}$$S or acceptable slippage degree tolerance value is less than or equal to 1%. If $$\varDelta$$Δ value of GDCSM is less than or equal to − 0.4%, then it behaves like stepper motor. GDCSM is suitable to hold and control vertical position of solar tracking system with low speed and step movement. Performance of geared DC motor experimentally showed better result than commercial available stepper motors like 28BYJ-48 or STP-43d1027-01.

A nonlinear optimization based decentralized PI controller for Two Input Two Output (TITO) is presented in this paper. Modelling of Quadruple tank minimum phase system with time delay is introduced here. The basic principles of nonlinear optimization are utilized to design the proposed PI controller in which the overshoot is bounded with constraints on the maximum closed-loop amplitude ratio, maximum closed loop width, gain and angle bounds. Besides, the control algorithm is designed for decoupled systems to reduce the loop interactions. Further, the first order plus dead time (FOPDT) model is derived for each of the decoupled subsystems to design the control law. The robust stability is analyzed by using Hurwitz and Upper triangular matrix of interrelated Kharitonov polynomials. The performance of the proposed control strategy is verified by MATLAB/SIMULINK software. The performance specifications of the simulation indicate that the suggested control strategy is more efficient.

The performances of the Proportional-Integral controller, Fuzzy Logic controller, and Subtractive Fuzzy Clustering-based PI controller (SFC-PI) have been investigated for regulating the level in a Quadruple Tank System with Dead Time (QTSWDT). The QTSWDT is an ideal benchmark to test various control approaches since it has nonlinear dynamics and complicated interactions between tanks. While classic PI controllers are successful in controlling linear systems, they face difficulties in regulating the nonlinearities and cross-couplings inherent in QTSWDT. Fuzzy logic controllers offer extended adaptation to nonlinearities but require substantial tuning. The SFC-PI controller, which offers subtractive fuzzy clustering to instinctively generate fuzzy rules, surpasses the other techniques by significantly reducing ISE, IAE, settling time, and peak overshoot. Simulation outputs disclose that the SFC-PI controller has the best overall performance, making it a competent choice for complex nonlinear control applications

A correction to this paper has been published: https://doi.org/10.1007/s42452-021-04542-3