scholarly journals Dynamic Model and Nonlinear Control for a Two Degrees of Freedom First Generation Tidal Energy Converter**This work has been partially supported by the Spanish Ministerio de Economía y Competitividad under Research Grant DPI2014-53499R and hiring of Miss Marina P. Portilla was funded by the GITERM research group from the Universidad Politecnica de Madrid.

2016 ◽  
Vol 49 (23) ◽  
pp. 373-379 ◽  
Author(s):  
L. Fernández ◽  
E. Segura ◽  
M.P. Portilla ◽  
R. Morales ◽  
J.A. Somolinos
Keyword(s):  
Nonlinear Control ◽  
Dynamic Model ◽  
Research Group ◽  
Degrees Of Freedom ◽  
First Generation ◽  
Tidal Energy ◽  
Energy Converter ◽  
Two Degrees Of Freedom ◽  
Research Grant

Dynamic Model and Performances of 2-DOF Mechanisms

2004 ◽  
Author(s):  
Raffaele Di Gregorio
Keyword(s):  
Dynamic Model ◽  
Degrees Of Freedom ◽  
Optimal Path ◽  
Two Degrees Of Freedom ◽  
Manipulator Dynamics ◽  
Dynamic Performances

Tools that make it possible to measure the performances of manipulators are essential in many technical applications, for instance, when the optimal path to accomplish a task has to be chosen, or when different manipulator architectures have to be compared. This paper proposes new indices that fully describe the passive dynamic performances of manipulators with two degrees of freedom (dof). The proposed indices make it possible to compare the passive dynamic performances of different manipulator architectures, which can perform the same tasks, and can be used to build diagrams which highlight the effects of variations in the manipulator geometry on the manipulator dynamics. These features make them easy to be used in a design context. Finally, one application of the proposed indices will be presented and discussed.

Modeling and Control Design for an Inlet Metering Valve-Controlled Pump Used to Control Actuator Velocity Via H-Infinity and Two-Degrees-of-Freedom Methods

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Hasan H. Ali ◽  
Roger C. Fales ◽  
Noah D. Manring
Keyword(s):  
Fluid Flow ◽  
Control System ◽  
Dynamic Model ◽  
Degrees Of Freedom ◽  
Closed Loop ◽  
High Efficiency ◽  
Hydraulic Cylinder ◽  
Velocity Control ◽  
Hydraulic Actuator ◽  
Two Degrees Of Freedom

Using a unique inlet metering pump with fixed displacement and speed, this work introduces a new way to control a linear hydraulic actuator velocity. The inlet metering system consists of an inlet metering valve that adjusts the hydraulic fluid flow that enters the pump and a fixed displacement pump. Fluid is supplied to the inlet metering valve at a fixed pressure. Energy losses associated with flow metering in the system are reduced because the pressure drop across the inlet metering valve can be small compared to a traditional valve-controlled system. A velocity control system is designed using the inlet metering pump to control the fluid flow into a hydraulic cylinder. First, the valve dynamic model is ignored, the open-loop response is studied, and closed-loop proportional and proportional derivative controllers are designed. Next, the valve dynamic model is included and closed-loop proportional integral derivative, H∞, and two-degrees-of-freedom controllers are designed. Designs with the goals of stability and performance of the system are considered so that a precise velocity control system for the hydraulic cylinder is achieved. In addition to the potentially high efficiency of this system, there is potential for low-cost, fast-response, and less complicated dynamics compared to other systems. The results show that the velocity control system can be designed so that the system is stable for all cases and with 0% overshoot and no oscillation depending on valve dynamics using the two-degrees-of-freedom controller for tracking the desired velocity.

Dynamic model and performances of 2-DOF manipulators

Robotica ◽  
2005 ◽  
Vol 24 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Raffaele Di Gregorio
Keyword(s):  
Dynamic Model ◽  
Degrees Of Freedom ◽  
Optimal Path ◽  
Two Degrees Of Freedom ◽  
Manipulator Dynamics ◽  
Dynamic Performances

Tools that make it possible to measure the performances of manipulators are essential in many technical applications, for instance, when the optimal path to accomplish a task has to be chosen, or when different manipulator architectures have to be compared. This paper proposes some indices that fully describe the passive dynamic performances of manipulators with two degrees of freedom (dof). The pro- posed indices make it possible to compare the passive dynamic performances of different manipulator architectures, which can perform the same tasks, and can be used to build diagrams which highlight the effects of variations in the manipulator geometry on the manipulator dynamics. These features make them easy to be used in a design context. Finally, some applications of the proposed indices will be presented and discussed.

On the Performance of a Dual-Cylinder Wave-Energy Converter: Single Versus Two Degrees of Freedom

2016 ◽  
Author(s):  
Lu Wang ◽  
Daewoong Son ◽  
Ronald W. Yeung
Keyword(s):  
Wave Energy ◽  
Degrees Of Freedom ◽  
Early Stage ◽  
Outer Cylinder ◽  
Electrical Energy ◽  
Coaxial Cylinder ◽  
Wave Energy Converter ◽  
Irregular Waves ◽  
Energy Converter ◽  
Two Degrees Of Freedom

A recently developed dual (coaxial-)cylinder wave-energy converter (WEC) consists of inner and outer-cylinders, with the outer one sliding over the inner one. An effective design was to tension-tether the inner cylinder (Son and Yeung, OMAE2014-#24582) while the outer cylinder acts as a floater heaving in response to incident waves. Even though the idea was a success, there was significant scientific curiosity in our early stage of the design in the following context: if both cylinders were allowed to heave simultaneously and independently, what would be the implications on the energy-extraction performance and power-take-off constraints? In this paper, we report the detailed analysis conducted at the time of the design. To begin with, the hydrodynamic coefficients, namely, the added mass, radiation-damping, and wave-exciting force for the individually moving cylinders were solved using the method of matched eigenfunction expansions (Chau and Yeung, OMAE2012-#83987). We expanded that capability to allow coupling or interference hydro-dynamic coefficients to be computed in the current work. This coupling is shown to lead to two degrees of freedom of motion, one for each cylinder, with excitation forces on each based on reciprocity (Haskind’s) relations. The resulting relative heave motion between the cylinders is used to drive the permanent magnet linear generator (PMLG) to capture electrical energy. The performance of the WEC, in terms of capture width, is calculated for both regular-wave and irregular-wave conditions and is compared with that for the one degree-of-freedom system, fixed inner cylinder and heaving outer cylinder. The change in WEC performance in response to changing generator damping was found to be very different for the two cases. This behavior leads to very different optimal generator damping values in regular and irregular waves. The advantages and shortcomings of the two systems are compared and explained.

The scientific bases of autocontrol with vibration phase for a resonance beating-vibration system with two degrees of freedom driven by debalances

1996 ◽  
Vol 18 (2) ◽  
pp. 43-48
Author(s):  
Tran Van Tuan ◽  
Do Sanh ◽  
Luu Duc Thach
Keyword(s):  
Degrees Of Freedom ◽  
Regulation System ◽  
Vibration System ◽  
Two Degrees Of Freedom ◽  
System Operating

In the paper it is introduced a method for studying dynamics of beating-vibrators by means of digital calculation with the help of the machine in accordance with the needs by the helps of an available auto regulation system operating with high reability.

scholarly journals Two Degrees of Freedom Slip Controller with Lateral Torque Distribution

2020 ◽  
Vol 53 (2) ◽  
pp. 14450-14455
Author(s):  
Wolfgang Degel ◽  
Stefan Lupberger ◽  
Dirk Odenthal ◽  
Naim Bajcinca
Keyword(s):  
Degrees Of Freedom ◽  
Torque Distribution ◽  
Two Degrees Of Freedom

scholarly journals Torque Ripple Suppression of PMSM Based on Robust Two Degrees-of-Freedom Resonant Controller

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1015
Author(s):  
Mingfei Huang ◽  
Yongting Deng ◽  
Hongwen Li ◽  
Jing Liu ◽  
Meng Shao ◽  
...  
Keyword(s):  
Control Strategy ◽  
Measurement Errors ◽  
Degrees Of Freedom ◽  
Control Method ◽  
Torque Ripple ◽  
Current Loop ◽  
Two Degrees Of Freedom ◽  
Robust Stability Analysis ◽  
Resonant Controller ◽  
Testing Environments

This paper concentrates on a robust resonant control strategy of a permanent magnet synchronous motor (PMSM) for electric drivers with model uncertainties and external disturbances to improve the control performance of the current loop. Firstly, to reduce the torque ripple of PMSM, the resonant controller with fractional order (FO) calculus is introduced. Then, a robust two degrees-of-freedom (Robust-TDOF) control strategy was designed based on the modified resonant controller. Finally, by combining the two control methods, this study proposes an enhanced Robust-TDOF regulation method, named as the robust two degrees-of-freedom resonant controller (Robust-TDOFR), to guarantee the robustness of model uncertainty and to further improve the performance with minimized periodic torque ripples. Meanwhile, a tuning method was constructed followed by stability and robust stability analysis. Furthermore, the proposed Robust-TDOFR control method was applied in the current loop of a PMSM to suppress the periodic current harmonics caused by non-ideal factors of inverter and current measurement errors. Finally, simulations and experiments were performed to validate our control strategy. The simulation and experimental results showed that the THDs (total harmonic distortion) of phase current decreased to a level of 0.69% and 5.79% in the two testing environments.

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