Today modern simulations solutions in the wind turbine industry have achieved a high degree of co... more Today modern simulations solutions in the wind turbine industry have achieved a high degree of complexity and detail in result. Limitations exist when it is time to validate model results against measurements. Regarding Model validation it is of special interest to identify mode frequencies and to differentiate them from the different excitations. A wind turbine is a complex device and measurements regarding any part of the assembly show a lot of noise. Input excitations are difficult or even impossible to measure due to the stochastic nature of the environment. Traditional techniques for frequency analysis or features extraction are widely used to analyze wind turbine sensor signals, but have several limitations specially attending to non stationary signals (Events). A new technique based on autoregresive analysis techniques is introduced here for a specific application, a comparison and examples related to different events in the wind turbine operations are presented.
An accelerated flexural fatigue test rig was developed in which imposed displacements are mechani... more An accelerated flexural fatigue test rig was developed in which imposed displacements are mechanically controlled. For bending tests, frequencies up to 20 Hz and large strains are simultaneously possible. The innovative feature of the test is the design of a five-point bending (5PB) setup with rotating supports, which allows applying bidirectional deformation with boundary conditions similar to a clamped one allowing to apply high strain values with small displacements of the load points. Test rig description and the control program which permits changing the load rate and the speed are presented. Geometrical corrections in bending test setups are presented taking into account the specific boundary conditions of the aforementioned supports. The test rig is validated by comparison with a universal fatigue testing machine. The application of a fatigue statistical model is presented to correlate different fatigue tests, reducing the required amount of tests to obtain the material fatigue properties. Finally, composite T700 fatigue properties are presented applying the proposed test setup and statistical model.
IKerlan's Orthosis (IKO) is an upper limb exoskeleton oriented to increasing human force during r... more IKerlan's Orthosis (IKO) is an upper limb exoskeleton oriented to increasing human force during routine activity at the workplace. Therefore, it can be considered as a force-amplification device conceived to work in collaboration with the human arm and implementing biomimetic principles. The aim of the proposed design is to find the best compromise between maximum reachable workspace and minimum moving mass, which are the key factors for obtaining an ergonomic, wearable exoskeleton. It consists of five actuated degree of freedom (DoF) to move the human arm and three non-actuated DoF between the back and shoulder to allow relative displacement of the sterno-clavicular joint. Conventional electrical motors are used for most of the DoF and pneumatic muscles for one of them (forearm rotation). Power transmission is based on Bowden cables. This paper presents the IKO design, the mechanical structure of a first prototype and the redesign process from an aesthetic point of view. Controller setup and control strategies are also shown, together with dynamic performance from experimental results.
International Journal of Modelling, Identification and Control, 2010
The feasibility of implementing virtual-labs based on complex Modelica models is demonstrated. To... more The feasibility of implementing virtual-labs based on complex Modelica models is demonstrated. To this end, the design and implementation of the following three virtual-labs is discussed: 1) a virtual-lab of a double-pipe heat exchanger, which is a useful tool for ...
Today modern simulations solutions in the wind turbine industry have achieved a high degree of co... more Today modern simulations solutions in the wind turbine industry have achieved a high degree of complexity and detail in result. Limitations exist when it is time to validate model results against measurements. Regarding Model validation it is of special interest to identify mode frequencies and to differentiate them from the different excitations. A wind turbine is a complex device and measurements regarding any part of the assembly show a lot of noise. Input excitations are difficult or even impossible to measure due to the stochastic nature of the environment. Traditional techniques for frequency analysis or features extraction are widely used to analyze wind turbine sensor signals, but have several limitations specially attending to non stationary signals (Events). A new technique based on autoregresive analysis techniques is introduced here for a specific application, a comparison and examples related to different events in the wind turbine operations are presented.
An accelerated flexural fatigue test rig was developed in which imposed displacements are mechani... more An accelerated flexural fatigue test rig was developed in which imposed displacements are mechanically controlled. For bending tests, frequencies up to 20 Hz and large strains are simultaneously possible. The innovative feature of the test is the design of a five-point bending (5PB) setup with rotating supports, which allows applying bidirectional deformation with boundary conditions similar to a clamped one allowing to apply high strain values with small displacements of the load points. Test rig description and the control program which permits changing the load rate and the speed are presented. Geometrical corrections in bending test setups are presented taking into account the specific boundary conditions of the aforementioned supports. The test rig is validated by comparison with a universal fatigue testing machine. The application of a fatigue statistical model is presented to correlate different fatigue tests, reducing the required amount of tests to obtain the material fatigue properties. Finally, composite T700 fatigue properties are presented applying the proposed test setup and statistical model.
IKerlan's Orthosis (IKO) is an upper limb exoskeleton oriented to increasing human force during r... more IKerlan's Orthosis (IKO) is an upper limb exoskeleton oriented to increasing human force during routine activity at the workplace. Therefore, it can be considered as a force-amplification device conceived to work in collaboration with the human arm and implementing biomimetic principles. The aim of the proposed design is to find the best compromise between maximum reachable workspace and minimum moving mass, which are the key factors for obtaining an ergonomic, wearable exoskeleton. It consists of five actuated degree of freedom (DoF) to move the human arm and three non-actuated DoF between the back and shoulder to allow relative displacement of the sterno-clavicular joint. Conventional electrical motors are used for most of the DoF and pneumatic muscles for one of them (forearm rotation). Power transmission is based on Bowden cables. This paper presents the IKO design, the mechanical structure of a first prototype and the redesign process from an aesthetic point of view. Controller setup and control strategies are also shown, together with dynamic performance from experimental results.
International Journal of Modelling, Identification and Control, 2010
The feasibility of implementing virtual-labs based on complex Modelica models is demonstrated. To... more The feasibility of implementing virtual-labs based on complex Modelica models is demonstrated. To this end, the design and implementation of the following three virtual-labs is discussed: 1) a virtual-lab of a double-pipe heat exchanger, which is a useful tool for ...
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