1,721,120 research outputs found
Synchronous Motion Control of Dual-Cylinder Electrohydraulic Actuators through a Non-Time Based Scheme
Full text linkA NON-TIME BASED STRATEGY FOR THE COORDINATED MOTION CONTROL OF HYDRAULIC ACTUATORS
No full textDespite the extensive research concerning the motion control of a hydraulic systems, the coordinated motion (synchronized motion) of multi-axis hydraulic systems is still an open and challenging field. In such a frame, this paper presents an innovative non-time based control strategy for the coordinated motion control of multi-axis hydraulic systems. The proposed approach, named DRSC (Delayed Reference Synchronization Control) allows achieving the coordinated motion by delaying the position reference of each actuator on the basis of an action reference parameter, which plays therefore the role of a delayed time. Such a scalar variable is computed on the fly on the basis of a properly defined equivalent elastic error, which is in turn a function of the state of the system and of the position measurements.
The theory developed is demonstrated through numerical simulations by applying it to the path tracking control of a two-axis hydraulic system
Modelli e schemi per il controllo del moto di attuatori idraulici
No full textThis thesis deals with the modeling and control of electohydraulic systems.
On basis on an accurate nonlinear model, an innovative position control scheme is proposed. Such a control scheme is mady by some decoupled actions, each one aimed at achieving a specific target in the dynamic response of the system.
Besides that, an original and innovative scheme for the coordinated motion control of multi-dof hydraulic systems is proposed. Such a control scheme, referred to as Delayed Reference Synchronization Control, aims at reducing the synchronization error by delaying the references of the inner position loop of the axis, on basis on an equivalent elastic error.
The effectiveness of both control schemes is assessed by numerical simulations by means of an accurate simulator employed in Simulink
Dynamic compensation of load cell response in high speed weighing devices through Shaper-Based Filters
No full textImproving active eigenvector assignment through passive modifications
Full text linkSpecifications on the dynamic behavior of feedback-controlled vibrating systems are often expressed in terms of its eigenstructure, i.e. eigenvalues and eigenvectors. The notion of controllability establishes the possibility to assign eigenvalues through state feedback, but it is not adequate to assure the assignment of arbitrary eigenvectors. Indeed, assignable eigenvectors are just those belonging to the allowable vector subspace, which depends on the physical properties of the vibrating system (mass, damping and stiffness matrices) and of the actuators. To overcome this limitation, this paper proposes a hybrid approach that exploits passive modification of the system physical parameters to modify the allowable subspace in such a way that it spans (or closely approximates) the desired eigenvectors. Then, once that the system modifications have been computed, standard techniques for control synthesis can be employed to compute the gains assigning the desired poles and the eigenvectors. The modification of the allowable subspace is cast in this work as a rank minimization problem, which can be efficiently tackled through semi-definite programming. The proposed method is numerically validated on a lumped parameter system, by proving that the assignment of eigenvectors by hybrid control is significantly enhanced compared with sole active control
From dynamic structural modification to concurrent passive and active control in mechatronic system design
No full textSimultaneous active and passive control for eigenstructure assignment in lightly damped systems
No full textThe assignment of the eigenstructure (i.e. eigenvalues and eigenvectors) in vibrating systems is an effective way to improve their dynamic performances. System controllability ensures that the poles of the controlled system are exactly assigned but it does not allow to assign arbitrary desired eigenvectors. To this purpose, this paper proposes a novel method for vibration control in lightly damped systems through the concurrent synthesis of passive structural modifications and active state (or state derivative) feedback control gains. Indeed, the suitable modification of the inertial and elastic parameters allows to enlarge the range of assignable eigenvectors. The problem is formulated as an optimization problem, where constraints are introduced to assure the feasibility of the physical system modifications while avoiding spillover phenomena. The experimental application to the eigenstructure assignment on a manipulator proves the method effectiveness
Introducing Shaper-based filters for the improvement of the load cell response in dynamic weighing systems
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