Robust two-degree-of freedom control optimally balancing feedforward plant inversion and feedforward closed loop inversion

2021 ◽  
Author(s):  
Leopoldo Jetto ◽  
Valentina Orsini
Keyword(s):  
Closed Loop ◽  
Degree Of Freedom ◽  
Two Degree Of Freedom

Two-Degree-of-Freedom Helicopter Closed-Loop Identification through a Cascade Controller

2011 ◽  
Vol 403-408 ◽  
pp. 4649-4658 ◽  
Author(s):  
Pouya Ghalei ◽  
Alireza Fatehi ◽  
Mohamadreza Arvan
Keyword(s):  
Closed Loop ◽  
Flight Simulation ◽  
Degree Of Freedom ◽  
Input Output ◽  
Closed Loop Identification ◽  
Practical Algorithm ◽  
Nonlinear Autoregressive Model ◽  
And Control ◽  
Nonlinear Autoregressive ◽  
Two Degree Of Freedom

Input-Output data modeling using multi layer perceptron networks (MLP) for a laboratory helicopter is presented in this paper. The behavior of the two degree-of-freedom platform exemplifies a high order unstable, nonlinear system with significant cross-coupling between pitch and yaw directional motions. This paper develops a practical algorithm for identifying nonlinear autoregressive model with exogenous inputs (NARX) and nonlinear output error model (NOE) through closed loop identification. In order to collect input-output identifier pairs, a cascade state feedback (CSF) controller is introduced to stabilize the helicopter and after that the procedure of system identification is proposed. The estimated models can be utilized for nonlinear flight simulation and control and fault detection studies.

Two-degree-of-freedom control design for ball screw driving table using full-closed loop

2004 ◽  
Vol 2004.57 (0) ◽  
pp. 441-442
Author(s):  
Hiroshi HAMAMATSU ◽  
Kentaro Kondo ◽  
Shigeru FUTAMI ◽  
Teruo TSUJI ◽  
Akihiro YAMAMOTO ◽  
...  
Keyword(s):  
Closed Loop ◽  
Control Design ◽  
Degree Of Freedom ◽  
Ball Screw ◽  
Screw Driving ◽  
Two Degree Of Freedom

Two Degree-of-Freedom Hysteresis Compensation for a Dynamic Mirror With Antagonistic Piezoelectric Stack Actuation

2013 ◽  
Author(s):  
James A. Mynderse ◽  
George T. C. Chiu
Keyword(s):  
Input Signal ◽  
Control Strategy ◽  
Closed Loop ◽  
Loop System ◽  
Degree Of Freedom ◽  
Closed Loop System ◽  
Loop Control ◽  
Hysteresis Compensation ◽  
Hysteresis Control ◽  
Two Degree Of Freedom

A methodology for designing a low-computation, high-bandwidth strategy for closed-loop control of a hysteretic system without a priori knowledge of the desired trajectory is presented. The resulting two degree-of-freedom hysteresis control strategy is applied to a dynamic mirror with antagonistic piezoelectric stack actuation. Hysteresis compensator is performed by a finite state machine switching polynomials for hysteresis inversion based on the input signal slope. Residual error after hysteresis compensation is corrected by an LQR feedback controller. Experimental results demonstrate effectiveness of the hysteresis compensator and closed-loop system under the proposed hysteresis control strategy. For the triangular input signal tested, the closed-loop system achieves a 91.5% reduction in hysteresis uncertainty with 60 kHz sample rate.

A Linkage Design for Direct-Drive Robot Arms

1985 ◽  
Vol 107 (4) ◽  
pp. 536-540 ◽  
Author(s):  
Haruhiko Asada ◽  
Il Hwan Ro
Keyword(s):  
Mechanism Design ◽  
Closed Loop ◽  
Degree Of Freedom ◽  
Resultant Force ◽  
Direct Drive ◽  
New Approach ◽  
Link Mechanism ◽  
Linkage Design ◽  
Manipulator Link ◽  
Two Degree Of Freedom

A new approach to manipulator link mechanism design is presented. Given torque-speed characterisics of actuators and an arm link mechanism, the resultant force-speed characteristics at the tip of the arm are analyzed. The link mechanism is optimized so that the end point speed and force are within appropriate ranges. This method is applied to a two-degree-of-freedom direct-drive arm. Direct-drive arms, in general, tend to have excessively fast operating ranges, whereas output forces are extremely small. A closed-loop five-bar-link mechanism is applied to the direct-drive arm, and the link dimensions are optimized in order to achieve appropriate force and speed ranges at the arm tip without using reducers.

Design of Robust Two-Degree-of-Freedom Controllers for Position Servos Using H-Infinity Theory

1992 ◽  
Vol 206 (2) ◽  
pp. 135-142 ◽  
Author(s):  
R Piché ◽  
S Pohjolainen ◽  
T Virvalo
Keyword(s):  
Closed Loop ◽  
Synthesis Method ◽  
Degree Of Freedom ◽  
Linear Feedback ◽  
Closed Loop System ◽  
Feedback Controllers ◽  
H Infinity ◽  
Structured Singular Value ◽  
Performance Specifications ◽  
Two Degree Of Freedom

Linear feedback controllers for position servos are designed using the structured singular value optimization (Doyle's μ-synthesis) method. The method produces a two-degree-of-freedom controller, including both the feedback and the prefilter, which is ‘performance robust’, in the sense that the closed-loop system is guaranteed to meet performance specifications in the presence of unmodelled dynamics. A detailed design of a low-order controller for a hydraulic position servo, including numerical non-linear simulation results, is presented.

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