A Reactive and Efficient Walking Pattern Generator for Robust Bipedal Locomotion

Available possibilities to prevent a biped robot from falling down in the presence of severe disturbances are mainly Center of Pressure (CoP) modulation, step location and timing adjustment, and angular momentum regulation. In this paper, we aim at designing a walking pattern generator which employs an optimal combination of these tools to generate robust gaits. In this approach, first, the next step location and timing are decided consistent with the commanded walking velocity and based on the Divergent Component of Motion (DCM) measurement. This stage which is done by a very small-size Quadratic Program (QP) uses the Linear Inverted Pendulum Model (LIPM) dynamics to adapt the switching contact location and time. Then, consistent with the first stage, the LIPM with flywheel dynamics is used to regenerate the DCM and angular momentum trajectories at each control cycle. This is done by modulating the CoP and Centroidal Momentum Pivot (CMP) to realize a desired DCM at the end of current step. Simulation results show the merit of this reactive approach in generating robust and dynamically consistent walking patterns

Power and velocity control of wind turbines by adaptive fuzzy controller during full load operation

© 2016, University of Sistan and Baluchestan. All rights reserved. Research on wind turbine technologies have focused primarily on power cost reduction. Generally, this aim has been achieved by increasing power output while maintaining the structural load at a reasonable level. However, disturbances, such as wind speed, affect the performance of wind turbines, and as a result, the use of various types of controller becomes crucial. This paper deals with two adaptive fuzzy controllers at full load operation. The first controller uses the generated power, and the second one uses the angular velocity as feedback signals. These feedback signals act to control the load torque on the generator and blade pitch angle. Adaptive rules, derived from the fuzzy controller, are defined based on the differences between state variables of the power and angular velocity of the generator and their nominal values. The results, which are compared with verified results of reference controller, show that the proposed adaptive fuzzy controller in full load operation has a higher efficiency than that of reference ones, insensitive to fast wind speed variation that is considered as disturbance

Dynamic System Identification of Smart Structures

Peer reviewed: YesNRC publication: Ye

Lqg control of flexible structures using piezoelements

Flexible space structures have serious problems with vibration, position and shape control. Long decay of vibration, flexibility-fatigue and instability are common problems in these structures, hi this paper an efficient active control system using piezoelectric transducers for a flexible structure is presented. The PVDF (Polarized homopolymer of Vinylidene Fluoride) piezofilms and the PZT (Lead-Zirconaie-Titanate) piezoceramics are used as sensors and actuators respectively. The LQG method, based on a full state feedback, has been used to design the control system. The paper shows that piezoelectric transducers can be used efficiently in the active control of flexible structures. Results show that the LQG compensator could be implemented in practice

Development of an Active Control System for a Smart Fin

Peer reviewed: YesNRC publication: Ye