Unmanned Aerial Vehicles (UAVs) have been used extensively in many applications, such as surveillance, medical transportation and delivery tasks. These applications usually involve an attachment system to connect a payload. However, when connected to such a coupled system, the UAV exhibits lower flight performance mainly due to gust loads. Mathematical modeling is used in this paper to illustrate the comparison between an UAV with a coupled system and a conventional UAV. Proportional Derivative (PD) and Sliding Mode Control (SMC) approaches are used to evaluate the vibrations of the payload, and the UAV trajectory subjected to Dryden gust. This work therefore uses these methods to investigate the dynamic response of a quadrotor-type UAV equipped with a payload and a flexible attachment system.

This paper compares two periodic control methods, the optimal H 2 and the periodic static output feedback (POF), to reduce the helicopter rotor vibrations. Actively twisted blades with Macro-Fibre Composite (MFC) piezoelectric actuators are used. The design model is based on a simplified aerodynamic model and on a multi-body model of the Bo 105 isolated rotor with the original blades replaced by actively twisted ones. The performance of the two controllers in alleviating hub loads is verified with improved simulations based on a free-wake model.

The vibration control of smart structure is considered in this paper. Membrane SAR antenna structure with piezoelectric sensors and actuators is taken as an example. The dynamic model is build up based on vector form intrinsic finite element (VFIFE) method. The four nodes membrane element, sensor element and actuator element for VFIFE are presented. By decentralized control stratagem, the bending and torsional vibrations of the membrane SAR antenna can be decoupled on measurement and driving control. The fuzzy control and adaptive fuzzy control are applied to suppress the bending and torsional vibrations of the membrane SAR structure. In the numerical experiment section, form finding is first carried out, then vibration control simulations are studied. The results demonstrate that adaptive fuzzy control algorithm can suppress the vibrations more effectively than the fuzzy control algorithm.

This work gives an overview of the theoretical and experimental achievements of mechatronics applied to fluid film bearings. Compressible and uncompressible fluids are addressed. Rigid and elastic (deformable) bearing profiles are investigated. Hydraulic, pneumatic, magnetic and piezoelectric actuators are used. The ideas of combining control techniques, informatics with hydrodynamic, thermo-hydrodynamic, elasto-hydrodynamic and thermo-elasto-hydrodynamic lubrication techniques are carefully explored in this paper, considering theoretical as well as experimental aspects. The main goal of using controllable fluid film bearings is to improve the overall machine performance by: controlling the lateral vibration of rigid and flexible rotating shafts; modifying bearing dynamic characteristics, such as stiffness and damping properties; increasing the rotational speed ranges by enhancing damping and eliminating instability problems, for example, by compensating cross-coupling destabilizing effects; reducing start-up torque and energy dissipation in bearings; compensating thermal effects. It is shown that such controllable fluid film bearings can act as “smart” machine components and be applied to rotating and reciprocating machines with the goal of avoiding unexpected stops of plants, performing rotor dynamic tests and identifying model parameters “on site”. Emphasis is given to the controllable lubrication (hybrid and active) applied to different types of oil film bearings under different lubrication regimes, i.e., as tilting-pad journal bearings, multi-recess journal bearings and plain journal bearings. After a comprehensive overview of the theoretical and experimental technological advancements achieved in university laboratories, the feasibility of industrial applications is highlighted, trying to foresee the future trends of such mechatronic devices.

This paper presents a novel trajectory planning method for a flexible Cartesian robot manipulator in a point-to-point motion. In order to obtain an exact mathematical model, the parameters of the equation of motion are determined from an identification experiment. An artificial neural network is employed to generate the desired base position, and then, a particle swarm optimization technique is used as the learning algorithm, in which the sum of the displacements of the manipulator is chosen as the objective function. We show that the residual vibrations of the manipulator can be suppressed by minimizing the displacement of the manipulator. The effectiveness and validity of the proposed method are demonstrated by comparing the simulation and experimental results.

Les besoins accrus d'encapsulation et d'autonomie des dispositifs decontrôle vibratoire ont ouvert le domaine des matériauxpiézoélectriques shuntés. De par ses propriétésphysiques, l'élément piézoélectrique convertit unepartie d'énergie vibratoire en énergie électrique. Lefait de connecter un circuit électrique (un circuit de shunt)aux bornes du patch modifie la dynamique du système complet(structure + patchs piézoélectriques) et offre ainsi despossibilités de le contrôler. C'est ce que nous nommeronscontrôle vibratoire passif dans le cas où le circuit deshunt est constitué de composants passifs (Résistances etinductances physiques). Dans la littérature, les dispositifs employant desstratégies de contrôle se focalisent principalement surl'efficacité obtenue en termes de facteur d'amortissement modal.Les flux d'énergie entre les différents éléments dusystème complet ne sont pas optimisés. Nous proposons dedévelopper un critère d'optimisation structurale qui prenden compte la dissipation induite non seulement en termesd'amortissement modal mais également en termes d'amplituded'énergie dissipée. Ce critère intègre des grandeursfacilement calculables via un code de calcul par éléments-finis. Il est à noter que l'une des principales difficultésde modélisation de ce type de structures est liée à lacondition électrique qui varie. Il est nécessaire d'employerun modèle complet ou suffisamment représentatif pourcalculer les modes de résonance de la structure à tensionnulle (condition de Dirichlet électrique ) et à courant nul(condition de Neumann électrique). Nous appliquerons notrecritère à une poutre élancée sur laquelle estimplantée un patch piézoélectrique pour différentesconditions aux limites et différents types de polarisation. Nousnous focaliserons sur le contrôle du premier mode de flexion de lastructure.

This paper presents investigations into the applications and performance of positive and negative input shapers in command shaping techniques for the vibration control of a flexible robot manipulator. A constrained planar single-link flexible manipulator is considered and the dynamic model of the system is derived using the finite element method. An unshaped bang-bang torque input is used to determine the characteristic parameters of the system for design and evaluation of the input shaping control techniques. The positive and specified amplitude negative input shapers are designed based on the properties of the system. Simulation results of the response of the manipulator to the shaped inputs are presented in the time and frequency domains. Performances of the shapers are examined in terms of level of vibration reduction, time response specifications and robustness to parameters uncertainty. The effects of derivative order of the input shaper on the performance of the system are investigated. Finally, a comparative assessment of the impact amplitude polarities of the input shapers on the system performance is presented and discussed.

Structural flexibility is an inherent characteristic of a class of macro-micro manipulators consisting of a rigid micro manipulator mounted on a long-reach (flexible) macro manipulator. Vibrations caused by flexibility make it difficult to achieve accurate control of the end-point of the micro manipulator. In this paper, we develop a control strategy that can be applied to such a system. An experimental test-bed has been developed in which a 6 DOF PUMA 560 manipulator is mounted on a compliant platform. The control strategy consists of a rigid body inverse dynamics controller together with a neural network based strategy for damping out the oscillations due to the flexible base. Experimental results obtained from the test-bed are presented to show the effectiveness of the proposed control scheme.

This paper discusses a technique for identifying the joint parameters of a modular robot in order to study the dynamic characteristics of the whole structure and to realise dynamic control. A method for identifying the joint parameters of the structure applying fuzzy logic combined with a genetic algorithm has been studied using a 9-DOF modular redundant robot. A Genetic Algorithm was used in the fuzzy optimisation, which helped to avoid converging to locally optimal solutions and made the results identified much more reasonable. The joint parameters of a 9-DOF modular redundant robot have been identified.