This paper introduces a novel hybrid vibration control of an industrial flexible link manipulator (FLM) with carbon-fiber reinforced polymer (CFRP) composite material. The hybrid controller consists ...of a closed-loop direct strain feedback controller (DSFC) and a new open-loop input shaper (OLIS), and its performance is examined and compared by numerical simulation and experiment. Vibration attenuation is also verified by a spare sensor, an accelerometer. Thanks to the design of an analog isolator circuit, data acquisition of the real-time experiments are carried out noise-free from the servo driver. Reduced-order-model (ROM) is generated for the composite link with three different loading conditions and model for servo system is derived via system identification. Impulse force test hammer (IFTH) equipment is used to excite the system with force input and the results of the experiments/simulations confirm that the controller is robust against the impulse disturbances. As a result, a decrease of 88 ± 6.9 percent in vibration amplitudes and a decrease of 90 ± 7 percent in vibration duration confirms that the proposed controller is effective for vibration control of the flexible arm even under disturbance. Controller performance also enabled the FLM to work with payloads 16 times of its own weight.
A flexible robot arm can be modeled as a lumped-parameter multi-degree-of-freedom mass–spring system. The actuator at one end positions the payload at the other end. The flexibility causes the ...vibration of the payload at the end point. This paper considers a 4-degree-of-freedom mass–spring system. A closed loop active vibration control system is analyzed to suppress the end-point vibrations. The mathematical model of the system is established by using the Lagrange equations. The average of the displacements of the masses is used for the feedback. A PID control is applied. The numerical solution is obtained by integrating the control action into the Newmark method. The instantaneous average displacement is subtracted from the reference input to find the error signal value at a time step in the Newmark solution. The PID control action is applied to find the actuator signal value in the time step. This input value is used to find the displacements for the subsequent time step. The process is continued until the steady-state value is approximately reached. The analytical solution is given by using the Laplace transform method to check the validity of the Newmark solution. It is observed that the numerical and analytical results are in good agreement. The integration of the control action into Newmark solution as presented in this study can be extended to finite element solutions to simulate the control of complex mechanical systems.
•Fast Fourier transform is proposed for vibration control of a flexible manipulator.•The calculation time is 36 h in ANSYS and 1 second only for the FFT method.•Proposed method is verified with ANSYS ...and experimental results.•FFT method can be used to study the vibration control of complex mechanical systems.
Transient vibration analyses of structures with complex shapes are performed by finite element (FE) methods. Transient vibration analyses take long processing times for the systems having large number of degrees of freedom. A method performing the transient analyses very fast using the Fast Fourier Transform (FFT) is introduced in this work, and it is applied to a curved manipulator. Various analyses are required to determine the input parameters for vibration control, and each analysis takes long FE solution times.
In this work, an FFT method is developed where the samples of the impulse response of the system under study is obtained by the FE software ANSYS first. The samples of the transfer function are then obtained by FFT, and transient responses are found for various vibration control parameters by using FFT. Transient response results for the complex system considered in this study are obtained approximately in 1 s with FFT method, while it takes 36 h with ANSYS.
A one degree of freedom system is considered to verify the results of FFT method. Newmark's numerical, ANSYS, and FFT method results are compared, and it is observed that the results are in good agreement. A curved non-uniform steel manipulator with a complex shape is considered after the verification. The samples of the impulse response of the manipulator is found by ANSYS. Then, FFT method is used to obtain transient responses. A trapezoidal velocity profile is considered to analyze the residual vibration. The effect of the deceleration time on the root-mean-square (rms) values of the residual vibration is studied experimentally and using FFT method. It is observed that the results are in good agreement, and it is concluded that FFT method introduced in this study is very effective to study transient vibration problems in complex systems.
This paper presents different modeling technique approaches of the single-link uniform cross-sectional shape manipulators. Three different materials of manipulators which are epoxy-glass and ...carbon-fiber for composite manipulators and steel manipulator are considered for both simulation and experimental analyses. Three different modelling techniques which are solid, beam and shell models are used for both manipulators. The study consists of three steps. In the first step, the manipulators are modeled in ANSYS for finite element analyses. In the second step, modal analysis is carried out in order to find the frequencies of the manipulators. In the third step, transient analysis is performed to investigate the success of different modeling approaches with experimental results. It is observed that the simulation results with three different modeling approaches have well matched with the experimental results and then, elapsed times for the transient analyses are investigated to find the appropriate modeling technique for the manipulator.
Tomato (Solanum lycopersicum (Solanaceae)), susceptible to significant yield loss due to pests, is particularly impacted by Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), a pest that directly ...and profoundly influences tomato yields. Consequently, early detection of T. absoluta damage intensity on leaves using machine learning or artificial intelligence-based algorithms is crucial for effective pest control. In this ground-breaking study, the galleries generated by T. absoluta were examined via field images using the Decision Trees (DTs) algorithm, a machine learning method. The unique advantage of DTs over other algorithms is their inherent capacity to identify complex and vague shapes without the necessity of feature extraction, providing a more streamlined and effective approach. The DTs algorithm was meticulously trained using pixel values from the leaf images, leading to the classification of pixels within regions with and without galleries on the leaves. Accordingly, the gallery intensity was determined to be 9.09% and 35.77% in the test pictures. The performance of the DTs algorithm, as evidenced by a high coefficient of determination (R²) and an accuracy rate of 0.98 and 0.99 respectively, testifies to its robust predictive and classification abilities. This pioneering study has far-reaching implications for the future of precision agriculture, potentially informing the development of advanced algorithms that can be integrated into autonomous vehicles. The integration of DTs in such applications, thanks to their distinctive ability to handle complex and indistinct shapes without the need for feature extraction, sets the stage for a new era of efficient and effective pest control strategies.
Residual vibrations occur after stopping the movement of flexible manipulators. Accuracy at the end-point positioning decreases if residual vibration amplitudes increase. Productivity decreases in ...the high speed applications since the settling time required for this residual vibration delays subsequent operations. In this study, the vibration control of single-link flexible manipulators with a payload is studied numerically and experimentally. The mathematical model of a planar manipulator is established by the finite element method (FEM). Then, the transient analysis is realized by the Newmark method. The FEM results are verified by the simulation results obtained ANSYS and experiment. Then, a curved manipulator is studied by ANSYS as the Newmark solution is not valid. Simulation results also are verified by experiments. Cases for different stopping positions and motion times are created using the trapezoidal and triangular velocity profiles. The time parameters of these motion profiles based on the first natural frequency of the manipulators are determined for the vibration control. The root mean square values calculated from the residual vibration signals, and reduction ratios are presented for the cases. It is observed from the results that the residual vibration amplitudes of the manipulators are successfully suppressed by selecting appropriate deceleration times.
Bu çalışmada, girdi şekillendirme yoluyla tek eksenli esnek kompozit manipülatörün titreşim kontrolünü incelemek için Hızlı Fourier Dönüşümü'nü (FFT) kullanan bir yöntem tanıtılmıştır. FFT yöntemi, ...ANSYS tarafından elde edilebilen sistemin darbe cevabını kullanır. Ardından, çeşitli girdiler için FFT yöntemi ile titreşim cevapları bulunur. Yöntem önce 4 serbestlik dereceli bir sistemde doğrulanmıştır. Analitik olarak Laplace dönüşüm yöntemi ile sayısal olarak Newmark yöntemi ile ve doğrudan ANSYS programında elde edilen cevaplar, FFT yöntemi kullanılarak bulunan cevaplar ile karşılaştırılmıştır. Daha sonra, doğal frekansların ve darbe cevabının bulunduğu ANSYS programında tek eksenli kompozit bir manipülatör modellenmiştir. FFT yöntemi, çeşitli trapez hız profillerine sahip girdiler için titreşim cevaplarını elde etmek için kullanılır. Hareket boyunca hareket sonrası titreşimleri elde eden dinamik analiz için hesaplama süresi ANSYS'de 22 saat ve FFT yöntemi için sadece 1 saniye sürmektedir. ANSYS tarafından bulunan doğal frekanslar ve FFT yönteminin bulduğu titreşim cevapları için benzetim sonuçları deneysel sonuçlarla karşılaştırılmıştır ve sonuçlar uyumlu çıkmıştır. Hız profilinin yavaşlama süresinin titreşimi kontrol etmek için etkili olduğu gözlemlenmektedir. Hesaplama süreleri göz önüne alındığında, FFT yöntemi karmaşık mekanik sistemlerin titreşim kontrolünü incelemek için kullanılabilir.
Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy with an aggressive clinical course and poor prognosis. The genetic abnormalities in BPDCN are heterogeneous; ...therefore, its molecular pathogenesis and the prognostic importance of genomic alterations associated with the disease are not well defined. Here we report a case of BPDCN with a novel AFF4::IRF1 fusion predicted to lead to a loss-of-function of the IRF1 tumor suppressor, somatic mutations of ASXL1, TET2, and MYD88, as well as multiple intrachromosomal deletions. The patient showed resistance to Tagraxofusp and Venetoclax, and he died about 16 months after diagnosis. Considering the predicted effect of the AFF4::IRF1 fusion on IRF1’s antitumor effects and immune regulation, and the possibility of its relevance to the aggressive course observed in this case, we propose further evaluation of the clinical significance of this fusion in BPDCN in future cooperative group studies and the consideration of therapeutic strategies aimed at restoring IRF1-dependent antineoplastic effects in such cases.
Abstract Mitochondrial glutamyl-tRNA synthetase is a major component of protein biosynthesis that loads tRNAs with cognate amino acids. Mutations in the gene encoding this enzyme have been associated ...with a variety of disorders related to oxidative phosphorylation. Here, we present a case of leukoencephalopathy with thalamus and brainstem involvement and high lactate (LTBL) presenting a biphasic clinical course characterized by delayed psychomotor development and seizure. High-throughput sequencing revealed a novel compound heterozygous mutation in mitochondrial glutamyl-tRNA synthetase 2 (EARS2), which appears to be causative of disease symptoms.
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