Pitch Control of Three Bladed Large Wind Energy Converters—A Review

Modern multi-megawatt wind turbines are currently designed as pitch-regulated machines, i.e., machines that use the rotation of the blades (pitching) in order to adjust the aerodynamic torque, such that the power is maintained constantly throughout a wide range of wind speeds when they exceed the design value (rated wind speed). Thus, pitch control is essential for optimal performance. However, the pitching activity is not for free. It introduces vibrations to the tower and blades and generates fatigue loads. Hence, pitch control requires a compromise between wind turbine performance and safety. In the past two decades, many approaches have been proposed to achieve different objectives and to overcome the problems of a wind energy converter using pitch control. The present work summarizes control strategies for problem of wind turbines, which are solved by using different approaches of pitch control. The emphasis is placed on the bibliographic information, but the merits and demerits of the approaches are also included in the presentation of the topics. Finally, very large wind turbines have to simultaneously satisfy several control objectives. Thus, approaches like collective and individual pitch control, tower and blade damping control, and pitch actuator control must coexist in an integrated control system.

Design and Simulation of a Flexible Bending Actuator for Solar Sail Attitude Control

This paper presents the design of a flexible bending actuator using shape memory alloy (SMA) and its integration in attitude control for solar sailing. The SMA actuator has advantages in its power-to-weight ratio and light weight. The bending mechanism and models of the actuator were designed and developed. A neural network based adaptive controller was implemented to control the non-linear nature of the SMA actuator. The actuator control modules were integrated into the solar sail attitude model with a quaternion PD controller that formed a cascade control. The feasibility and performance of the proposed actuator for attitude control were investigated and evaluated, showing that the actuator could generate 1.5 × 10−3 Nm torque which maneuvered a 1600 m2 CubeSat based solar sail by 45° in 14 h. The results demonstrate that the proposed SMA bending actuator can be effectively integrated in attitude control for solar sailing under moderate external disturbances using an appropriate controller design, indicating the potential of a lighter solar sail for future missions.

Speed- and Range-based Filter Design for Dual-Stage Actuator Control

Dual-stage actuators, which combine two actuators with different characteristics, have gained interest due to their large-range, high-resolution positioning capabilities. Control of such systems is challenging because it requires balancing the relative contributions of the individual actuators in terms of speed, range and precision. The most common approach is to allocate effort to the actuators based on frequency but this can lead to misallocation in the case of low-frequency short-range trajectories. In this paper, the problem of trajectory allocation in dual-stage actuator systems is addressed using a recently developed range-based filter. The theoretical basis of the range-based filter is rigorously derived for the first time and insights regarding its use, specifically its reinterpretation as a speed-based filter, and its range-frequency response characteristics are presented. The new analysis not only explains the behavior of the filter clearly, but it provides a more robust strategy for incorporating range constraints in filter design for different desired trajectories.

Modular Design of Full Body Exoskeleton suit for Industry, Construction and Military Purpose

Exoskeleton suits can be considered as a wearable robotic item ,where the main inution is to increase,improve& boost the physical performance of operator/user by a desired margin , it has a great practicality in the present time as it can be implemented in a variety of filed extending from Health sector to industries .The scope of this is to design a full-body, rigid, Active, performance type mobile-exoskeleton prototype, by targeting it as mainly applicable for the Industry sector , Defence sector & Civil-(construction, fire & safety department, etc) Sectors , which has seen to be taking a leap in to this genre .This paper explicates the methodology for the design which was modeled in “Solidworks” and analysys of mechanical strucuture – performed by “Ansys Workbench”& selection of actuation mechanism with a coustomised design which was validated by a series of analysis in “Altiar Flux Motor” , this paper also scrutinize very succinctly the “gait” cycle & its phases ,it summarise the necessity of the “gait” analysis- which was performed by “Opensim”from which data was acquired for the analysis of designed prototype & for the guidance in actuation of the prototype by prediction & restriction of drive controller value to the normal gait values during locomotion by “gait assist function”,where the actuator control is primarly by the sensing of a series of “Strain guage” belts attached to the users muscles , 4 different control drivers used for actuation out of which for thigh joint the control drive was coustamised , the battery houses 728 high-performance Lithium-ion cells 0f “Panasonic-NCR18650B 3400MAh”,for cooling system a common aluminium heat sink was used .the other critical factors which was considered during the designing was cost-effectiveness, minimal maintenance, ergonomic , efficiency and safety of the designed prototype is also pithily considered . the total weight of the designed prototype model was 79Kg & was able to lift & locomote at 1.36m/s with a payload of 258kg.