Dynamical Analysis and Stabilizing Control of Inclined Rotational Translational Actuator Systems

Rotational translational actuator (RTAC) system, whose motions occur in horizontal planes, is a benchmark for studying of control techniques. This paper presents dynamical analysis and stabilizing control design for the RTAC system on a slope. Based on Lagrange equations, dynamics of the inclined RTAC system is achieved by selecting cart position and rotor angle as the general coordinates and torque acting on the rotor as general force. The analysis of equilibriums and their controllability yields that controllability of equilibriums depends on inclining direction of the inclined RTAC system. To stabilize the system to its controllable equilibriums, a proper control Lyapunov function including system energy, which is used to show the passivity property of the system, is designed. Consequently, a stabilizing controller is achieved directly based on the second Lyapunov stability theorem. Finally, numerical simulations are performed to verify the correctness and feasibility of our dynamical analysis and control design

Rotorcraft Blade Pitch Control Through Torque Modulation

Micro air vehicle (MAV) technology has broken with simple mimicry of manned aircraft in order to fulfill emerging roles which demand low-cost reliability in the hands of novice users, safe operation in confined spaces, contact and manipulation of the environment, or merging vertical flight and forward flight capabilities. These specialized needs have motivated a surge of new specialized aircraft, but the majority of these design variations remain constrained by the same fundamental technologies underpinning their thrust and control. This dissertation solves the problem of simultaneously governing MAV thrust, roll, and pitch using only a single rotor and single motor. Such an actuator enables new cheap, robust, and light weight aircraft by eliminating the need for the complex ancillary controls of a conventional helicopter swashplate or the distributed propeller array of a quadrotor. An analytic model explains how cyclic blade pitch variations in a special passively articulated rotor may be obtained by modulating the main drive motor torque in phase with the rotor rotation. Experiments with rotors from 10 cm to 100 cm in diameter confirm the predicted blade lag, pitch, and flap motions. We show the operating principle scales similarly as traditional helicopter rotor technologies, but is subject to additional new dynamics and technology considerations. Using this new rotor, experimental aircraft from 29 g to 870 g demonstrate conventional flight capabilities without requiring more than two motors for actuation. In addition, we emulate the unusual capabilities of a fully actuated MAV over six degrees of freedom using only the thrust vectoring qualities of two teetering rotors. Such independent control over forces and moments has been previously obtained by holonomic or omnidirection multirotors with at least six motors, but we now demonstrate similar abilities using only two. Expressive control from a single actuator enables new categories of MAV, illustrated by experiments with a single actuator aircraft with spatial control and a vertical takeoff and landing airplane whose flight authority is derived entirely from two rotors

適応制御戦略に基づく車輪型二足歩行ロボットのバランス安定性の向上

Tohoku University林部充宏課

Magnetic Actuators and Suspension for Space Vibration Control

The research on microgravity vibration isolation performed at the University of Virginia is summarized. This research on microgravity vibration isolation was focused in three areas: (1) the development of new actuators for use in microgravity isolation; (2) the design of controllers for multiple-degree-of-freedom active isolation; and (3) the construction of a single-degree-of-freedom test rig with umbilicals. Described are the design and testing of a large stroke linear actuator; the conceptual design and analysis of a redundant coarse-fine six-degree-of-freedom actuator; an investigation of the control issues of active microgravity isolation; a methodology for the design of multiple-degree-of-freedom isolation control systems using modern control theory; and the design and testing of a single-degree-of-freedom test rig with umbilicals

Single wheel robot: gyroscopical stabilization on ground and on incline.

by Loi-Wah Sun.Thesis (M.Phil.)--Chinese University of Hong Kong, 2000.Includes bibliographical references (leaves 77-81).Abstracts in English and Chinese.Abstract --- p.iAcknowledgments --- p.iiiContents --- p.vList of Figures --- p.viiList of Tables --- p.viiiChapter 1 --- Introduction --- p.1Chapter 1.1 --- Motivation --- p.1Chapter 1.1.1 --- Literature review --- p.2Chapter 1.1.2 --- Gyroscopic precession --- p.5Chapter 1.2 --- Thesis overview --- p.7Chapter 2 --- Dynamics of the robot on ground --- p.9Chapter 2.1 --- System model re-derivation --- p.10Chapter 2.1.1 --- Linearized model --- p.15Chapter 2.2 --- A state feedback control --- p.16Chapter 2.3 --- Dynamic characteristics of the system --- p.18Chapter 2.4 --- Simulation study --- p.19Chapter 2.4.1 --- The self-stabilizing dynamics effect of the single wheel robot --- p.21Chapter 2.4.2 --- The Tilting effect of flywheel on the robot --- p.23Chapter 2.5 --- Dynamic parameters analysis --- p.25Chapter 2.5.1 --- Swinging pendulum --- p.25Chapter 2.5.2 --- Analysis of radius ratios --- p.27Chapter 2.5.3 --- Analysis of mass ratios --- p.30Chapter 3 --- Dynamics of the robot on incline --- p.33Chapter 3.1 --- Modeling of rolling disk on incline --- p.33Chapter 3.1.1 --- Disk rolls up on an inclined plane --- p.37Chapter 3.2 --- Modeling of single wheel robot on incline --- p.39Chapter 3.2.1 --- Kinematic constraints --- p.40Chapter 3.2.2 --- Equations of motion --- p.41Chapter 3.2.3 --- Model simplification --- p.43Chapter 3.2.4 --- Linearized model --- p.46Chapter 4 --- Control of the robot on incline --- p.47Chapter 4.1 --- A state feedback control --- p.47Chapter 4.1.1 --- Simulation study --- p.49Chapter 4.2 --- Backstepping-based control --- p.51Chapter 4.2.1 --- Simulation study --- p.53Chapter 4.2.2 --- The effect of the spinning rate of flywheel --- p.56Chapter 4.2.3 --- Simulation study --- p.58Chapter 4.2.4 --- Roll up case --- p.58Chapter 4.2.5 --- Roll down case --- p.58Chapter 5 --- Motion planning --- p.61Chapter 5.1 --- Performance index --- p.61Chapter 5.2 --- Condition of rolling up --- p.62Chapter 5.3 --- Motion planning of rolling Up --- p.65Chapter 5.3.1 --- Method I : Orientation change --- p.65Chapter 5.3.2 --- Method II : Change the initial velocities --- p.69Chapter 5.4 --- Wheel rolls Down --- p.70Chapter 5.4.1 --- Terminal velocity of rolling body down --- p.73Chapter 6 --- Summary --- p.75Chapter 6.1 --- Contributions --- p.75Chapter 6.2 --- Future Works --- p.76Bibliography --- p.7

Validation of an extended foot-ankle musculoskeletal model using in vivo 4D CT data

openPer simulare il movimento del corpo umano, è necessario creare dei modelli che rappresentino le strutture anatomiche. In questo elaborato ci si concentrerà su un modello biomeccanico del complesso piede-caviglia implementato in un software per la modellazione muscoloscheletrica, nella fattispecie OpenSim. OpenSim è un software che consente di sviluppare modelli di strutture muscoloscheletriche e creare simulazioni dinamiche in grado di stimare i parametri interni delle strutture anatomiche (come le forze muscolari e di contatto tra le ossa), attraverso la simulazione della cinematica e la cinetica del movimento delle varie strutture coinvolte. Nel presente elaborato, si è partiti dallo studio di un dataset, acquisito da Boey et al. (2020) tramite scansione 4D CT in combinazione con un dispositivo di manipolazione del piede su soggetti sani e pazienti affetti da instabilità cronica di caviglia. In questo modo è stata valutata la cinematica dell’osso del piede durante il cammino simulato. Lo scopo di questo elaborato è quindi validare un modello del complesso piede-caviglia sviluppato da Malaquias et al. (2016), partendo dai dati acquisiti affinché, imponendo il movimento della pedana, la simulazione restituisca delle variabili comparabili a quelle reali. Il modello muscoloscheletrico esteso del complesso piede-caviglia è composto da sei segmenti rigidi e cinque articolazioni anatomiche (caviglia, sottoastragalica, mediotarsica, tarsometatrsale e metatarsofalangea) per un totale di otto gradi di libertà. A questo modello è stata aggiunto una pedana (per simulare il dispositivo di manipolazione utilizzato nella sperimentazione) e sono stati incrementati i gradi di libertà delle articolazioni di caviglia e sottoastragalica, per ottenere tre gradi di libertà ciascuna. Dopodiché, è stato imposto un movimento combinato di inversione\eversione ed ab-adduzione alla pedana ed è stato valutato il movimento del modello del piede rispetto al dataset.To simulate the movement of the human body, it is necessary to create models that represent anatomical structures. In this thesis the focus will be placed on a biomechanical model of the complex foot-ankle implemented in a software for musculoskeletal modeling, in particular OpenSim. OpenSim is software that allows to develop models of musculoskeletal structures and create dynamic simulations capable of estimating the internal parameters of anatomical structures (such as muscle and contact forces between bones), through the simulation of the kinematics and kinetics of the movement of the various anatomical structures involved. In this paper, the starting point was the study of a dataset, acquired by Boey et al. (2020) with 4D CT scan in combination with a foot manipulator device. The study was run on healthy subjects as well as patients with chronic ankle instability. In this way, the kinematics of the movement of the foot bones during simulated gait was evaluated. The aim of this project was to validate a model of the foot-ankle complex, developed by Malaquias et al. (2016), starting from the acquired data, so that, by imposing the movement of the platform, the simulation would return variables comparable to the dataset. This extended musculoskeletal model of the foot-ankle complex is composed of six rigid segments and five anatomical joints (ankle, subtalar, midtarsal, tarsometatarsal, and metatarsophalangeal) for a total of eight degrees of freedom. A footplate was added to this model (to simulate the foot manipulator device utilized in the experiment) and the degrees of freedom of the ankle and subtalar joints were increased, to obtain three degrees of freedom each. After that, a combined inversion\eversion and plantar\dorsiflexion movement was imposed on the footplate and the movement of the foot model was evaluated against the dataset

Proceedings of the ECCOMAS Thematic Conference on Multibody Dynamics 2015

This volume contains the full papers accepted for presentation at the ECCOMAS Thematic Conference on Multibody Dynamics 2015 held in the Barcelona School of Industrial Engineering, Universitat Politècnica de Catalunya, on June 29 - July 2, 2015. The ECCOMAS Thematic Conference on Multibody Dynamics is an international meeting held once every two years in a European country. Continuing the very successful series of past conferences that have been organized in Lisbon (2003), Madrid (2005), Milan (2007), Warsaw (2009), Brussels (2011) and Zagreb (2013); this edition will once again serve as a meeting point for the international researchers, scientists and experts from academia, research laboratories and industry working in the area of multibody dynamics. Applications are related to many fields of contemporary engineering, such as vehicle and railway systems, aeronautical and space vehicles, robotic manipulators, mechatronic and autonomous systems, smart structures, biomechanical systems and nanotechnologies. The topics of the conference include, but are not restricted to: ● Formulations and Numerical Methods ● Efficient Methods and Real-Time Applications ● Flexible Multibody Dynamics ● Contact Dynamics and Constraints ● Multiphysics and Coupled Problems ● Control and Optimization ● Software Development and Computer Technology ● Aerospace and Maritime Applications ● Biomechanics ● Railroad Vehicle Dynamics ● Road Vehicle Dynamics ● Robotics ● Benchmark ProblemsPostprint (published version

Towards Robust Bipedal Locomotion:From Simple Models To Full-Body Compliance

Thanks to better actuator technologies and control algorithms, humanoid robots to date can perform a wide range of locomotion activities outside lab environments. These robots face various control challenges like high dimensionality, contact switches during locomotion and a floating-base nature which makes them fall all the time. A rich set of sensory inputs and a high-bandwidth actuation are often needed to ensure fast and effective reactions to unforeseen conditions, e.g., terrain variations, external pushes, slippages, unknown payloads, etc. State of the art technologies today seem to provide such valuable hardware components. However, regarding software, there is plenty of room for improvement. Locomotion planning and control problems are often treated separately in conventional humanoid control algorithms. The control challenges mentioned above are probably the main reason for such separation. Here, planning refers to the process of finding consistent open-loop trajectories, which may take arbitrarily long computations off-line. Control, on the other hand, should be done very fast online to ensure stability. In this thesis, we want to link planning and control problems again and enable for online trajectory modification in a meaningful way. First, we propose a new way of describing robot geometries like molecules which breaks the complexity of conventional models. We use this technique and derive a planning algorithm that is fast enough to be used online for multi-contact motion planning. Similarly, we derive 3LP, a simplified linear three-mass model for bipedal walking, which offers orders of magnitude faster computations than full mechanical models. Next, we focus more on walking and use the 3LP model to formulate online control algorithms based on the foot-stepping strategy. The method is based on model predictive control, however, we also propose a faster controller with time-projection that demonstrates a close performance without numerical optimizations. We also deploy an efficient implementation of inverse dynamics together with advanced sensor fusion and actuator control algorithms to ensure a precise and compliant tracking of the simplified 3LP trajectories. Extensive simulations and hardware experiments on COMAN robot demonstrate effectiveness and strengths of our method. This thesis goes beyond humanoid walking applications. We further use the developed modeling tools to analyze and understand principles of human locomotion. Our 3LP model can describe the exchange of energy between human limbs in walking to some extent. We use this property to propose a metabolic-cost model of human walking which successfully describes trends in various conditions. The intrinsic power of the 3LP model to generate walking gaits in all these conditions makes it a handy solution for walking control and gait analysis, despite being yet a simplified model. To fill the reality gap, finally, we propose a kinematic conversion method that takes 3LP trajectories as input and generates more human-like postures. Using this method, the 3LP model, and the time-projecting controller, we introduce a graphical user interface in the end to simulate periodic and transient human-like walking conditions. We hope to use this combination in future to produce faster and more human-like walking gaits, possibly with more capable humanoid robots

Stability-Oriented Dynamics and Control of Complex Rigid-Flexible Mechanical Systems Using the Example of a Bucket-Wheel Excavator

Der Schwerpunkt dieser Arbeit liegt auf der Modellbildung und der Regelung von Schaufelradbaggerauslegern. Die Schaufelradbagger stellen eine besondere Art komplexer Maschinensysteme dar, die im Braunkohletagebau eingesetzt werden. Der Schaufelradausleger ist hierbei als dreidimensionaler elastischer Balken nach der EULER-BERNOULLI Balken-Hypothese modelliert. Durch den Erhalt von Termen höherer Ordnung in den nichtlinearen Relationen zwischen Verschiebung und Verzerrungen, sind Kopplungseffekte höherer Ordnung der gesamtheitlichen Verschiebung und der flexiblen Deformation mitberücksichtigt. Bei der Modellierung der geometrischen Nichtlinearität des dreidimensionalen elastischen Balkens wurde weiterhin die zusätzliche Elastizität von Hebekabeln miteinbezogen. Komplexere Bewegungen, speziell die geführte Bewegung in Kombination mit Grabkräften wurden aufgezeigt und diskutiert. Die Elastizität des Auslegers wurde in Bezug auf die Interaktion zwischen Schneidewerkzeug (Baggerschaufel) und Oberflächenmaterial berücksichtigt. Einflüsse von Kopplungen höherer Ordnung zwischen flexiblen Deformationen, Förderseilen und Grabgegenkräften auf das dynamische Verhalten des Schaufelradauslegers werden mithilfe intensiver Simulationsstudien dargestellt. Dynamische Phänomene, die sich aus den geometrischen und dynamischen Kopplungen höherer Ordnung ergeben, die der geführten Bewegung und den Grabgegenkräften ausgesetzt sind, wurden im Detail analysiert. Die destabilisierenden Einflüsse, die zu großen Deformationen des Systems führen, beruhen auf den oben genannten Kopplungen, werden in den Simulationsergebnissen gezeigt. Das entwickelte Model sowie die damit verbundene Abbildung des dynamischen Systems liefert somit eine gute Basis für weitere Untersuchungen der Systemstabilität in Zusammenhang mit den Grabgegenkräften. Das nichtlineare dynamische System des Schaufelradauslegers wird durch ein erweitertes lineares System mit Nichtlinearitäten eines passenden fiktiven Modells für die Ansteuerungsanalyse und Designzwecke approximiert. Ein PI-Beobachter wird basierend auf diesem erweiterten linearen System eingesetzt, der alle Zustände des Systems schätzen und das Zeitverhalten der Nichtlinearitten rekonstruiert. Von diesem Standpunkt aus ist die beobachtergestützte PI-Zustandsregelung in Kombination mit einer Störungs- Kompensationsregelung realisiert. Drei Störungs-Kompensationsregelungsansätze bestehen aus dem statischen Ansatz, dem Davison Ansatz und dem erweiterten Ansatz nach dem Davison wurden zur Kompensation der Nichtlinearitäten diskutiert. Anhand von Simulationsbeispielen wird die effiziente Unterdrückung von Vibrationen und der Systemstabilisierung des Schaufelradbaggers während des Grabprozesses gezeigt. Die Ergebnisse zeigen, dass der Davison Ansatz und der erweiterte Ansatz nach dem Davison die dynamische Verbesserung des Schwingungsverhaltens sowie Stabilisierung des Schaufelradbaggers gewähren können. Demnach kann die Produktivität und somit die Ertrag des Schaufelradbaggers erhöht werden.The focus of this thesis is the modeling and control of the boom of the Bucket-Wheel excavator, which represents a specific type of complex machine systems used in mining technology. Hereby the Bucket-Wheel boom is modeled as the three-dimensional flexible beam using the Euler-Bernoulli beam theory. Retaining higher-order terms in the nonlinear strain-displacement relationship, higher-order coupling effects between the overall motion and flexible deformations are considered in the modeling. Furthermore, the nonlinear modeling of the three-dimensional elastic boom is also considered with the additional elasticity of hoisting cables. More complex motions, especially the guided motion in combination with digging resistance forces, are mentioned and discussed. So far, the elasticity of the boom along with the interaction between the cutting head and the face material is taken into account. The effects of higher-order couplings between flexible deformations, hoisting cables, and digging resistance forces on dynamical responses of the Bucket-Wheel boom are illustrated by intensive simulation studies. Dynamic phenomena resulting from higher-order geometrical and dynamical couplings undergoing the guided motion and digging resistance forces are therefore analyzed in detail. The destabilizing effects leading to large deformations (may be critical) of the system due to the above mentioned couplings are shown in simulation results. Thus, the developed model as well as the related dynamic system representation gives a good base for the advanced study of the stability of the system in combination with the digging resistance forces. For control analysis and design purposes, the nonlinear dynamical system of the Bucket-Wheel boom is approximated by the extended linear system with nonlinearities modeled by a suitable fictitious model. Based on this extended linear system, a high-gain PI-Observer is applied to estimate all states of the system and to reconstruct the time behavior of the nonlinearities. From this point of view, a high-gain PI-Observer-based state feedback control is realized in combination with disturbance rejection control approaches. Three disturbance rejection control approaches including the static disturbance rejection control approach, Davison approach, and the extended approach of Davison are discussed for compensating nonlinearities. Simulation examples are included to illustrate the efficient suppression of vibrations as well as the stabilization of the system during the digging process of the Bucket-Wheel Excavator. The results show that the static disturbance rejection control approach cannot stabilize the system, while Davison approach and the extended approach of Davison can stabilize successfully the system with the suitable dynamic feedback terms. Consequently, application of these approaches can improve operating ranges of the Bucket-Wheel excavator. Therefore, an exploitation productivity of the Bucket-Wheel excavators can be increased