A method for the mechatronico analysis of parallel kinematics manipulators based on decoupling the dynamics of actuators and mechanism

287 p

A method for the mechatronico analysis of parallel kinematics manipulators based on decoupling the dynamics of actuators and mechanism

287 p

Mechatronic modeling of a parallel kinematics multi-axial simulation table based on decoupling the actuators and manipulator dynamics

In this work a mechatronic model was developed for a parallel Multi-Axial Simulation Table (MAST) mechanism. The dynamics of the mechanism was obtained using the principle of energy equivalence and Boltzmann–Hamel equations. In this way, the procedure to obtain the explicit dynamic equations is simplified and has the advantage of being systematic. Also, the actuators and the control were modeled and integrated to simulate and study the system’s positioning and torque. A remarkable contribution of this work is that the mechatronic model developed considers the mechanism as a disturbance to the actuators in a decoupled manner, allowing to easily evaluate alternative designs of whether the actuators, the mechanism or both. Additionally, the procedure taken has been validated with experimental data from an actual MAST prototype.The authors of this paper wish to acknowledge the funding received from the Spanish Government via the Ministerio de Economía y Competitividad (BES-2012-053723 under Project DPI2011-22955 and DPI2015-64450-R), the ERDF of the European Union, the Government of the Basque Country (SAIOTEK 2013 SAI13/245), and the financial support from the University of the Basque Country(UPV/EHU) under the program UFI 11/29

Experimental Validation of the Kinematic Design of 3PRS Compliant Parallel Mechanisms

In this paper, a procedure for the kinematic design of a 3-PRS compliant parallel manipulator of 3 degrees of freedom is proposed. First, under the assumption of small displacements, the solid body kinematics of the 3-PRS has been studied, performing a comprehensive analysis of the inverse and forward kinematic problem, and calculating the rotations that the revolute and spherical flexure joints must perform. Then, after defining some design requirements and therefore the necessary displacements to fulfill, a design process based on the finite element calculations has been stablished, giving the necessary guidelines to reach the optimal solution on a 3-PRS compliant mechanism. Also, a prototype has been tested, using a coordinate measuring machine to verify its dimensions and the resulting displacements in the end effector and the actuated joints. Finally, those measurements have been compared with the FEM and the rigid body kinematics predictions, contrasting the validity of those two modelling approaches for the kinematic design of compliant mechanisms.The authors of this paper wish to acknowledge the financial support received from the Spanish Government via the Ministerio de Educación y Ciencia (Project DPI2011-22955) and Ministerio de Economía y Competitividad (Project DPI2015-64450-R), the ERDF of the European Union, the Government of the Basque Country (Project GIC07/78, IT445-10 and SAIOTEK 2013 SAI13/245, SPC13UN011), and the University of the Basque Country (Project EHUA13/30 and Zabalduz-2012). Thanks are also addressed to Dr. Jorge Presa and Alfonso Urzainki from Egile Corporation XXI for their valuable contributions

Dynamic Model of a Compliant 3PRS Parallel Mechanism for Micromilling

The objective of this work is to develop a manipulator of 5 degrees of freedom for micromilling. It consists of a XY stage under a 3PRS compliant parallel mechanism, obtaining the advantages of the compliant joints as are higher repetitiveness, smoother motion and a higher bandwidth, due to the high precision demanded from the process, under 0.1 μm. In this work, the dynamics of the compliant stage will be developed. The modelling approach is based on the use of the Principle of Energy Equivalence combined with the Boltzmann-Hamel equations to analyze the rotational dynamics of the platform. A pseudo-rigid model has been assumed for the compliant joints, calculating the flexural and torsional stiffness by FEA. Finally, a prototype has been built and some preliminary results are shown comparing the simulation and the measurements.The authors of this paper wish to acknowledge the financial support received from the Spanish Government via the Ministerio de Economía y Competitividad (Project DPI2015-64450-R), the ERDF of the European Union, the Government of the Basque Country (Project GIC07/78, IT445-10 and SAIOTEK 2013 SAI13/245, SPC13UN011), and the University of the Basque Country (Zabalduz-2012

A Context-Aware Oil Debris-Based Health Indicator for Wind Turbine Gearbox Condition Monitoring

One of the greatest challenges of optimising the correct operation of wind turbines is detecting the health status of their core components, such as gearboxes in particular. Gearbox monitoring is a widely studied topic in the literature, nevertheless, studies showing data of in-service wind turbines are less frequent and tend to present difficulties that are otherwise overlooked in test rig based works. This work presents the data of three wind turbines that have gearboxes in different damage stages. Besides including the data of the SCADA (Supervisory Control And Signal Acquisition) system, additional measurements of online optical oil debris sensors are also included. In addition to an analysis of the behaviour of particle generation in the turbines, a methodology to identify regimes of operation with lower variation is presented. These regimes are later utilised to develop a health index that considers operation states and provides valuable information regarding the state of the gearboxes. The proposed health index allows distinguishing damage severity between wind turbines as well as tracking the evolution of the damage over time.This work was performed with the financial support of the FRONTIERS IV (ELKARTEK KK-2018/00096) Project financed by Eusko Jaurlaritza