Fuzzy-Immune-Regulated Adaptive Degree-of-Stability LQR for a Self-Balancing Robotic Mechanism: Design and HIL Realization

This letter formulates a fuzzy-immune adaptive system for the online adjustment of the Degree-of-Stability (DoS) of Linear-Quadratic-Regulator (LQR) procedure to strengthen the disturbance attenuation capacity of a self-balancing mechatronic system. The fuzzy-immune adaptive system uses pre-configured control input-based rules to alter the DoS parameter of LQR for dynamically relocating the closed-loop system's eigenvalues in the complex plane's left half. The corresponding changes in the eigenvalues are conveyed to the Riccati equation, which eventually yields the self-adjusting LQR gains. This arrangement allows for the flexible manipulation of the applied control effort and the response speed as the error conditions change. The efficacies of the self-tuning LQR scheme are verified by performing custom-designed hardware-in-the-loop experiments on the Quanser rotary inverted pendulum system. As compared to the DoS-LQR, the proposed controller improves the pendulum's transient recovery time, overshoots, input demands, and offsets by 32.3%, 50.5%, 33.9%, and 33.3%, respectively, under disturbances. These experimental outcomes verify that the proposed self-tuning LQR law considerably improves the system's disturbance attenuation capability

Complex-order PID controller design for enhanced blood-glucose regulation in Type-I diabetes patients

Type-I Diabetes (TID) is a chronic autoimmune disease that elevates the glucose levels in the patient’s bloodstream. This paper formulates a fractional complex-order Proportional-Integral-Derivative (PID) control strategy for robust Blood Glucose (BG) regulation in TID patients. The glucose-insulin dynamics in blood plasma are modeled via the Bergman-Minimal-Model. The proposed control procedure employs the ubiquitous fractional order PID controller as the baseline BG regulator. The design flexibility of the baseline regulator to effectively normalize the BG levels is enhanced by assigning complex orders to the integral and differential operators instead. The resulting Complex Order PID (CO-PID) regulator strengthens the controller’s robustness against abrupt variations in the patient’s BG levels caused by meal disturbances or sensor noise. The controller parameters are numerically optimized offline. The aforesaid propositions are justified by performing credible simulations in which the proposed controller is tasked to effectively track a set point value of 80 mg/dL from an initial state of hyperglycemia under various disturbance factors. As compared to the FO-PID controller, the CO-PID controller improves the reference tracking-error, transient recovery-time, and control expenditure by 13.1%, 33.4%, and 28.1%, respectively. The simulation results validate the superior reference-tracking accuracy of the proposed CO-PID controller for BG regulation

High prevalence of vitamin D deficiency and insufficiency in a low income peri-urban community in Karachi

Objective: To determine the frequency of vitamin D deficiency and insufficiency in a low-income peri-urban population.Methods: The cross-sectional study was conducted in a low-income, unplanned settlement in Karachi, and comprised apparently healthy adults who were recruited randomly with informed consent. Serum levels of 25-hydroxy vitamin D were measured using a kit obtained from Roche Diagnostics. One-way analysis of variance and logistic regression were used for statistical analysis.Results: Of the 858 subjects, 507(59%) were females and 351(41%) males (age range: 18-60 years). Prevalence estimates of vitamin D deficiency (\u3c20ng/ml) and insufficiency (20.0-29.9ng/ml) were found to be 501(58.4%) and 269(31.4%), respectively. Odds ratio of vitamin D deficiency was significantly higher in females compared to males after adjusting for education and smoking status (p=0.001).CONCLUSIONS: High prevalence of vitamin D deficiency among females in one of the peri-urban areas points towards a public health problem which requires attention of the medical community

Vitamin B12 deficiency--a major cause of megaloblastic anaemia in patients attending a tertiary care hospital

BACKGROUND: Folate and vitamin B12 deficiencies have been known to cause megaloblastic anaemia. Since the deficiencies of these two vitamins are very common in Pakistani population, it would be imperative to investigate their role in causing megaloblastic anaemia. The objective of this study was to find out the contribution of folate and vitamin B12 deficiencies in causing megaloblastic anaemia in our patient population. METHODS: In this retrospective cohort study, clinical records of 220 patients (101 females and 119 males with an age range of 1-80 years) who presented themselves with macrocytic anaemia at the Aga Khan University Hospital were collected. Data pertaining to complete blood count and serum levels of folate and vitamin B12 were analysed. RESULTS: The mean haemoglobin (Hb) level was 6.8 +/- 0.2 gm/dl. Sixty-nine percent of the patients had severe anaemia (Hb \u3c 8 gm/dl). Mean +/- SEM values of haemoglobin, serum folate and serum B12 were not significantly different between males and females (Hb 6.4 +/- 0.3 gm/dl vs 6.3 +/- 0.3 gm/dl; folate 6.9 +/- 0.8 etag/ml vs 7.8 +/- 1 etag/ml; B12 259 +/- 65 rhog/ml vs 225 +/- 45 rhog/ml, respectively). Linear regression analysis showed that serum folate was inversely related with the mean corpuscular volume (MCV, p = 0.04). Spearman\u27s correlation analysis indicated an inverse mild association between MCV and serum folate (correlation coefficient = -0.18). Folate deficiency was 43.4%, while vitamin B12 deficiency was 78.5% in these patients. Seventy-one percent of folate-deficient patients had vitamin B12 deficiency as well, while 26.1% of patients with B12 deficiency had a co-occurrence of folate deficiency. CONCLUSION: Vitamin B12 deficiency appears to be the major factor leading to megaloblastic anaemia in our study population. Inadequate dietary intake, over-cooking of our food and poor absorption might be contributing to high prevalence of vitamin B12 deficiency in this population

Effects Of Locus Of Control On Gender

The study was intended to determine the gender differences in the locus of control with academic achievement among secondary school science students of Wah Cantonment area. Locus of control means expectancy whether perceived reinforcement is under internal or external control. It is individual variations in his belief that what control the events in his life, himself or others. 270 students were chosen from the Federal Government High School for Girls and Boys and private secondary schools of Wah Cantonment area. 35 items self-developed questionnaire was administered to determine the locus of control. The instrument was validated by expert suggestions of concerned area. t-test was applied for numerical analysis by statistical package for social sciences (SPSS). It was concluded from the study results that the students have belief that they can or can’t control events that affect their academic achievement. The significant difference found between the mean locus of control scores of boys and the mean locus of control scores of girls. The boys were found superior to girls in their mean locus of control scores which shows that boys have comparatively strong belief then girls about the control of some events that affect their academic achievement

Adaptive optimal control of under-actuated robotic systems using a self-regulating nonlinear weight-adjustment scheme: Formulation and experimental verification

This paper formulates an innovative model-free self-organizing weight adaptation that strengthens the robustness of a Linear Quadratic Regulator (LQR) for inverted pendulum-like mechatronic systems against perturbations and parametric uncertainties. The proposed control procedure is devised by using an online adaptation law to dynamically adjust the state weighting factors of LQR's quadratic performance index via pre-calibrated state-error-dependent hyperbolic secant functions (HSFs). The updated state-weighting factors re-compute the optimal control problem to modify the state-compensator gains online. The novelty of the proposed article lies in adaptively adjusting the variation rates of the said HSFs via an auxiliary model-free online self-regulation law that uses dissipative and anti-dissipative terms to flexibly re-calibrate the nonlinear function's waveforms as the state errors vary. This augmentation increases the controller's design flexibility and enhances the system's disturbance rejection capacity while economizing control energy expenditure under every operating condition. The proposed self-organizing LQR is analyzed via customized hardware-in-loop (HIL) experiments conducted on the Quanser's single-link rotational inverted pendulum. As compared to the fixed-gain LQR, the proposed SR-EM-STC delivers an improvement of 52.2%, 16.4%, 55.2%, and 42.7% in the pendulum's position regulation behavior, control energy expenditure, transient recovery duration, and peak overshoot, respectively. The experimental outcomes validate the superior robustness of the proposed scheme against exogenous disturbances

Differentiation Property of Fractional Hankel Transform of a Function Involving Higher Order Derivatives

In engineering mathematics, integral transform is a widely used tool for solving linear differential equations, In recent  times  the newly born  fractional Hankel  transform has been started for   playing a very important    role  in various  fields of applied  mathematics and physics like fractional Fourier transform. This paper represent   a formalization of differentiation property of a function invoving  high order derivatives  of  newly introduced     fractional Hankel  transform. The differentiation property is  proved for different higher differential equations

Robust MPPT Control of Stand-Alone Photovoltaic Systems via Adaptive Self-Adjusting Fractional Order PID Controller

The Photovoltaic (PV) system is an eco-friendly renewable energy system that is integrated with a DC-DC buck-boost converter to generate electrical energy as per the variations in solar irradiance and outdoor temperature. This article proposes a novel Adaptive Fractional Order PID (A-FOPID) compensator with self-adjusting fractional orders to extract maximum power from a stand-alone PV system as ambient conditions change. The reference voltage is generated using a feed-forward neural network. The conventional FOPID compensator, which operates on the output voltage error of the interleaved buck-boost converter, is employed as the baseline maximum-power-point-tracking (MPPT) controller. The baseline controller is retrofitted with an online state-error-driven adaptation law that dynamically modifies the fractional orders of the controller’s integral and differential operators. The adaptation law is formulated as a nonlinear hyperbolic scaling function of the system’s state error and error-derivative variables. This augmentation supplements the controller’s adaptability, enabling it to manipulate flexibly the tightness of the applied control effort as the operating conditions change. The efficacy of the proposed control law is analyzed by carrying out customized simulations in the MATLAB Simulink environment. The simulation results show that the proposed MPPT control scheme yields a mean improvement of 25.4% in tracking accuracy and 11.3% in transient response speed under varying environmental conditions