Comparative Analysis of Input Shaping Techniques for Sway Control of Nonlinear Crane System

This paper compares output based input shaping with a conventional command shaping in suppressing sway of a nonlinear crane system. The output-based input shaping filter is designed using the output signal of the target system while conventional input shaping filters are designed using the natural frequency and damping ratio of the system. Zero vibration (ZV), zero vibration derivative (ZVD), zero vibration derivative, derivatives (ZVDD) and zero vibration and triple derivative (ZVDDD) were designed and compared with the output based filter to investigate the performances and robustness of the filters. Level of sway reduction of the payload and time response analysis is used to assess the performance of the shapers. Simulation results showed that the output based filter has a better performance and it is more robust compared to the conventional input shapers and does not require model information of the system

OUTPUT BASED INPUT SHAPING FOR OPTIMAL CONTROL OF SINGLE LINK FLEXIBLE MANIPULATOR

Endpoint residual vibrations and oscillations due to flexible and rigid body motions are big challenges in control of single link flexible manipulators, it makes positioning of payload difficult especially when using various payloads. This paper present output based input shaping with two different control algorithms for optimal control of single link flexible manipulators. Output based filter (OBF) is designed using the signal output of the system and then incorporated with both linear quadratic regulator (LQR) and PID separately for position and residual vibration control. The Robustness of these control algorithms are tested by changing the payloads from 0g to30g, 50g and 70g in each case. Based on MATLAB simulation results and time response analysis, LQR-OBF outperformed the PID-OBF in both tracking and vibration reduction

HYBRID POSITION AND VIBRATION CONTROL OF NONLINEAR CRANE SYSTEM

This paper presents comparative assessments of input shaping techniques using two different approaches, for sway reduction of cranes system. First, the shaper was designed at maximum load hoisting length while the second was designed at average load hoisting length. These were accomplished using curve fitting toolbox in MATLAB. In both case; Zero Vibration (ZV), Zero Vibration Derivative (ZVD) and Zero Vibration Derivative Derivatives (ZVDD) were designed. Average hoisting length (AHL) shapers performed better than the Maximum hoisting length (MHL) shapers. Proportional integral derivative (PID) was incorporated for position control. After successful implementation, Simulation results show that a precise payload positioning was achieved. AHL-ZVDD has superior performances in sway reduction and robustness.

Application of Non-Model Dependent Hybrid Higher-Order Differential Feedback Controller on Crane System

Gantry Crane is a machine used for shipping of goods from one point to another. Speed, accuracy and safety are of paramount importance in gantry crane (GC) operation, but operating GC results in unwanted sway which degrades the accuracy and safety. In this paper, hybrid control schemes are proposed for precise trolley position control and sway suppression in GC systems. Output Based input shaping (OBIS) filter was designed using the output of the system for sway suppression and proportional integral derivative (PID), linear quadratic regulator (LQR), higher order differential feedback (HODF) controllers were incorporated separately for precise trolley position control. Based on Simulation studies and analysis, it was observed that LQR-OBIS controller shown more precise tracking and higher sway reduction control. But HODFC-OBIS is a model-free control schemes hence more robust

Vibrations and Intelligent Tracking Control of Single Link Flexible Manipulator

Residual vibrations and oscillations at the Endpoint due to flexible body motions are big challenges in control of single link flexible manipulators. This makes payloads positioning very difficult and hence less efficient and low productivity. In this paper, a hybrid intelligent control of single link flexible manipulator is proposed. Output-based filter (OBF) was designed using the signal output of the system to suppress the tip deflections and it was incorporated with both linear quadratic regulator (LQR) controller and fuzzy logic controller for set point tracking control of the system. Based on the Simulation results, it was observed that, a good tracking and significant tip deflections reduction was achieved. This was measured using the time response analysis. OBF-LQR performed better and more compatible then OBF-fuzzy

Trends in pediatric tuberculosis diagnosis utilizing xpert Mycobacterium tuberculosis/Rifampicin in a poor-resource, high-burden region: A retrospective, multicenter study

Background: The burden of tuberculosis (TB) in Nigeria remains high, and diagnosis in children, a challenge. We aimed to document yield from Xpert Mycobacterium tuberculosis/rifampicin (MTB/RIF) as a mode of diagnosis for children and the variables associated with a positive result. Methods: This was a retrospective review of TB treatment cards of children aged 0–15 years managed from January 2017 to December 2021 across six public tertiary institutions in Nigeria. The data obtained were analyzed using the descriptive and inferential statistics. Statistical significance was set at P 10 years), the presence of pulmonary TB (PTB), and a negative human immunodeficiency virus (HIV) status were associated with positive Xpert MTB/RIF tests (P = 0.002, 0.001, and 0.012, respectively). Conclusion: The utilization of Xpert MTB/RIF in children increased in the years before the COVID-19 pandemic. Factors associated with MTB detection by Xpert MTB/RIF include older age, the presence of PTB, and a negative HIV status. Clinical and radiological evaluation continues to play vital roles in the diagnosis of childhood TB in Nigeria