A MIMO controller design for damping, tracking, and cross coupling reduction of nanopositioners

A nonlinear two time-scale dynamic inversion controller is designed. Actuator saturation in the spinning missile will limit the control commands responses. And the periodic motion and the physical limits of the actuator’s angle and angular velocity would make the respondent pseudo fin deflection angles much different from the desired dynamics. So a kind of command shaping method which limits the fin deflection angle commands in the pseudo body coordinates before the actuator’s limiter is proposed. Meanwhile, a feedback compensation method is applied to eliminate the cross coupling between the pitch and yaw channels in the actuator due to the spinning of the missile. Finally the performance of the controller with the command shaping and decoupling treatment is analyzed.

Download Full-text

Optimal Quantitative H_2 Controller Design for Twin Rotor MIMO System

Engineering and Technology Journal ◽

10.30684/etj.v38i12a.1618 ◽

2020 ◽

Vol 38 (12A) ◽

pp. 1880-1894

Author(s):

Mustafa K. Khreabet ◽

Hazem I. Ali

Keyword(s):

Control Algorithm ◽

Controller Design ◽

Mimo System ◽

Cross Coupling ◽

Optimization Methods ◽

Control Approach ◽

Optimal Values ◽

Frequency Domain Techniques ◽

Twin Rotor Mimo System ◽

Twin Rotor

In this paper, the control approach is used for achieving the desired performance and stability of the twin-rotor MIMO system. This system is considered one of the complex multiple inputs of multiple-output systems. The complexity because of the high nonlinearity, significant cross-coupling and parameter uncertainty makes the control of such systems is a very challenging task. The dynamic of the Twin Rotor MIMO System (TRMS) is the same as that in helicopters in many aspects. The Quantitative Feedback Theory (QFT) controller is added to the control to enhance the control algorithm and to satisfy a more desirable performance. QFT is one of the frequency domain techniques that is used to achieve a desirable robust control in presence of system parameters variation. Therefore, a combination between control and QFT is presented in this paper to give a new efficient control algorithm. On the other hand, to obtain the optimal values of the controller parameters, Particle Swarm Optimization (PSO) which is one of the powerful optimization methods is used. The results show that the proposed quantitative control can achieve more desirable performance in comparison to control especially in attenuating the cross-coupling and eliminating the steady-state error.

Download Full-text

An Accurate Discrete Current Controller for High-Speed PMSMs/Gs in Flywheel Applications

Energies ◽

10.3390/en13061458 ◽

2020 ◽

Vol 13 (6) ◽

pp. 1458

Author(s):

Xiang Zhang ◽

Yunlong Chen ◽

Yves Mollet ◽

Jiaqiang Yang ◽

Johan Gyselinck

Keyword(s):

Fundamental Frequency ◽

High Speed ◽

Controller Design ◽

Storage System ◽

Cross Coupling ◽

Sampling Period ◽

Energy Storage System ◽

Current Loop ◽

Current Controller ◽

Frequency Ratios

High-speed Permanent-Magnet Synchronous Motors/Generators (PMSMs/Gs) in a Flywheel Energy Storage System (FESS) are faced with high cross-coupling voltages and low switching-to-fundamental frequency ratios. High cross-coupling voltages between d-q axis current loops lead to transient current errors, which is more serious at lower switching-to-fundamental-frequency ratios. If the delays are not properly considered during the current controller design in a digital control system, the low switching-to-fundamental-frequency ratios may result in oscillatory or unstable responses. In this study, an accurate discrete current controller for high-speed PMSMs/Gs is proposed based on an accurate discrete model that takes the phase and magnitude errors generated during the sampling period into consideration, and an Extended State Observer (ESO) is applied to estimate and compensate the back EMF error. The cross-coupling problem is well settled, and the current loop dynamic at lower switching-to-fundamental frequency ratios is improved. Finally, the proposed discrete controller is validated on a 12,000 rpm PMSM/G prototype.

Download Full-text