28 research outputs found
Improvement of a Fixed Point Transformations and SVD-based Adaptive Controller
In this paper some refinement of a novel control approach is reported that fits to the “traditional line of thinking” according to which in the most practical cases neither very precise, nor even complete system model is needed for obtaining precise control for dynamical systems. The validity of this statement is briefly pointed out in the most popular approaches as the main idea of the “Robust Sliding Mode / Variable Structure Controllers”, in the Adaptive Inverse Dynamics and in the Slotine-Li Adaptive Controllers based on Lyapunov's 2nd Method, and in a recently published problem tackling using the simple geometric interpretation of the Singular Value Decomposition (SVD). In the present approach the originally proposed convergent, iterative Cauchy sequences are nonlinearly moderated to adaptively control a coupled nonlinear system, the cart plus double pendulum serving as popular paradigm of dynamicall not very well conditioned systems. It is shown that the proposed moderation removes the small sharp fluctuation in the control torque that inherently belonged to the original solution without significantly degrading the control quality. This statement is substantiated by simulation results.N/
A Higher Order Adaptive Approach to Tackle the Swinging Problem
In numerous practical applications precise control of a subsystem passively
connected to a precisely controllable subsystem by elastic connection is needed. As typical
example is a crane carrying its payload swinging on an elastic string can be mentioned.
From the point of view of control technology this task is interesting since the connected degree of freedom has little damping and it is apt to keep swinging accordingly. The traditional approaches apply the input shaping technology to assist the human operator responsible for the manipulation task. In the present paper a novel adaptive approach applying fixed point transformations based iterations having local basin of attraction is proposed for simultaneously tackle the problems originating from the imprecisions of the available dynamic model of the system to be controlled and the swinging phenomenon. In the simulation investigations presented a simple model consisting of two connected masspoints is considered: one of them can directly by controlled by control forces, the other one (in the role of the payload) is dragged by the controlled point via an elastic spring. The control considers the 4th time-derivative of the trajectory of the dragged system.N/
OGLE-2018-BLG-0799Lb: a Sub-Saturn-Mass Planet Orbiting a Very Low Mass Dwarf
We report the discovery and analysis of a sub-Saturn-mass planet in the microlensing event OGLE-2018-BLG-0799. The planetary signal was observed by several ground-based telescopes, and the planet-host mass ratio is q = (2.65±0.16)×10⁻³. The ground-based observations yield a constraint on the angular Einstein radius θ_E, and the microlens parallax π_E is measured from the joint analysis of the Spitzer and ground-based observations, which suggests that the host star is most likely to be a very low-mass dwarf. A full Bayesian analysis using a Galactic model indicates that the planetary system is composed of an M_(planet) = 0.22^(+0.19)_(−0.06) M_J planet orbiting an M_(host) = 0.080^(+0.080)_(−0.020) M⊙, at a distance of D_L = 4.42^(+1.73)_(−1.23) kpc. The projected planet-host separation is r⊥ = 1.27^(+0.45)_(−0.29) AU, implying that the planet is located beyond the snowline of the host star. However, because of systematics in the Spitzer photometry, there is ambiguity in the parallax measurement, so the system could be more massive and farther away
Observation of long ionizing tracks with the ICARUS T600 first half-module
F. Arneodo, B. Bade"ek, A. Badertscher, B. Baiboussinov, M. Baldo Ceolin, G. Battistoni, B. Bekman, P. Benetti, E. Bernardini, M. Bischofberger, A. Borio di Tigliole, R. Brunetti, A. Bueno, E. Calligarich, M. Campanelli, C. Carpanese, D. Cavalli, F. Cavanna, P. Cennini, S. Centro, A. Cesana, C. Chen, D. Chen, D.B. Chen, Y. Chen, D. Cline, Z. Dai, C. De Vecchi, A. Dabrowska, R. Dolfini*, M. Felcini, A. Ferrari, F. Ferri, Y. Ge, A. Gigli Berzolari, I. Gil-Botella, K. Graczyk, L. Grandi, K. He, J. Holeczek, X. Huang, C. Juszczak, D. Kie"czewska, J. Kisiel, T. Koz"owski, H. Kuna-Ciska", M. Laffranchi, J. Łagoda, Z. Li, F. Lu, J. Ma, M. Markiewicz, A. Martinez de la Ossa, C. Matthey, F. Mauri, D. Mazza, G. Meng, M. Messina, C. Montanari, S. Muraro, S. Navas-Concha, M. Nicoletto, G. Nurzia, S. Otwinowski, Q. Ouyang, O. Palamara, D. Pascoli, L. Periale, G. Piano Mortari, A. Piazzoli, P. Picchi, F. Pietropaolo, W. P ! o"ch"opek, T. Rancati, A. Rappoldi, G.L. Raselli, J. Rico, E. Rondio, M. Rossella, A. Rubbia, C. Rubbia, P. Sala, D. Scannicchio, E. Segreto, F. Sergiampietri, J. Sobczyk, J. Stepaniak, M. Szeptycka, M. Szleper, M. Szarska, M. Terrani, S. Ventura, C. Vignoli, H. Wang, M. W ! ojcik, J. Woo, G. Xu, Z. Xu, A. Zalewska, J. Zalipska, C. Zhang, Q. Zhang, S. Zhen, W. Zipper a INFN Laboratori Nazionali del Gran Sasso, s.s. 17bis Km 18+910, Assergi (L'Aquila), Italy b Institute of Experimental Physics, Warsaw University, Warszawa, Poland c Institute for Particle Physics, ETH H . onggerberg, Z . urich, Switzerland Dipartimento di Fisica e INFN, Universit " a di Padova, via Marzolo 8, Padova, Italy Dipartimento di Fisica e INFN, Universit " a di Milano, via Celoria 16, Milano, Italy f Institute of Physics, University of Silesia, Katowice, Poland Dipartimento di Fisica e INFN, Universit " a di Pavia, via Bassi 6, Pavia, Italy Dpto de F!isica Te ! orica y del Cosmos & C.A.F.P.E., Universidad de Granada, Avda. Severo Ochoa s/n, Granada, Spain Dipartimento di Fisica e INFN, Universit " a dell'Aquila, via Vetoio, L'Aquila, Italy CERN, CH-1211 Geneva 23, Switzerland Politecnico di Milano (CESNEF), Universit " a di Milano, via Ponzio 34/3, Milano, Ital
Application of robust fixed point transformations for technological operation of robots
A robot’s drive has to exert appropriate driving forces that can keep its arm and end effector at the proper position, velocity and acceleration, and simultaneously has to compensate for the effects of the contact forces arising between the tool and the workpiece depending on the needs of the actual technological operation. Balancing the effects of a priori unknown external disturbance forces and the inaccuracies of the available dynamic model of the robot is also important. Technological tasks requiring well prescribed end effector trajectories and contact forces simultaneously are challenging control problems that can be tackled in various manners
Application of Robust Fixed Point Transformations for Technological Operation of Robots
A robot’s drive has to exert appropriate driving forces that can keep its arm and end effector at the proper position, velocity and acceleration, and simultaneously has to compensate for the effects of the contact forces arising between the tool and the workpiece depending on the needs of the actual technological operation. Balancing the effects of a priori unknown external disturbance forces and the inaccuracies of the available dynamic model of the robot is also important. Technological tasks requiring well prescribed end effector trajectories and contact forces simultaneously are challenging control problems that can be tackled in various manners.info:eu-repo/semantics/publishedVersio
Adaptive tackling of the swinging problem for a 2 DOF crane – payload system
The control of a crane carrying its payload by an elastic string corresponds to a task in which precise, indirect control of a subsystem dynamically coupled to a directly controllable subsystem is needed. This task is interesting since the coupled degree of freedom has little damping and it is apt to keep swinging accordingly. The traditional approaches apply the input shaping technology to assist the human operator responsible for the manipulation task. In the present paper a novel adaptive approach applying fixed point transformations based iterations having local basin of attraction is proposed to simultaneously tackle the problems originating from the imprecise dynamic model available for the system to be controlled and the swinging problem, too. The most important phenomenological properties of this approach are also discussed. The control considers the 4th time-derivative of the trajectory of the payload. The operation of the proposed control is illustrated via simulation results
Fixed Point Transformations in the Adaptive Control of Fractional Order MIMO Systems
Though the formal mathematical idea of introducing noninteger order derivatives can be traced from the 17th century in a letter by L’Hospital in which he asked Leibniz what the meaning of D n y if n = 1/2 would be in 1695 [1], it was better outlined only in the 19th century [2, 3, 4]. Due to the lack of clear physical interpretation their first applications in physics appeared only later, in the 20th century, in connection with visco-elastic phenomena [5, 6]. The topic later obtained quite general attention [7, 8, 9], and also found new applications in material science [10], analysis of earth-quake signals [11], control of robots [12], and in the description of diffusion [13], etc.info:eu-repo/semantics/publishedVersio