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.

The variable, fractional-order discrete-time PD controller in the IISv1.3 robot arm control

Open Physics ◽  
2013 ◽  
Vol 11 (6) ◽  
Author(s):  
Piotr Ostalczyk ◽  
Dariusz Brzezinski ◽  
Piotr Duch ◽  
Maciej Łaski ◽  
Dominik Sankowski
Keyword(s):  
Fractional Order ◽  
Discrete Time ◽  
Output Signal ◽  
Closed Loop ◽  
Loop System ◽  
Robot Arm ◽  
Pd Controller ◽  
Closed Loop System ◽  
Loop Control ◽  
Robot Arm Control

AbstractIn this paper, the discrete differentiation order functions of the variable, fractional-order PD controller (VFOPD) are considered. In the proposed VFOPD controller, a variable, fractional-order backward difference is applied to perform closed-loop, system error, discrete-time differentiation. The controller orders functions which may be related to the controller input or output signal or an input and output signal. An example of the VFOPD controller is applied to the robot arm closed-loop control due to system changes in moment of inertia. The close-loop system step responses are presented.

scholarly journals Multi-criteria performance assessment based on closed-loop system identification

2021 ◽  
Author(s):  
Gustavo Sanchez
Keyword(s):  
System Identification ◽  
Closed Loop ◽  
Process Variable ◽  
Loop System ◽  
Closed Loop Control ◽  
Closed Loop System ◽  
Trade Off ◽  
Loop Control ◽  
Control Loops ◽  
Variable Energy

<div>A method to assess the performance of closed loop control loops, based on closed-loop system identification. This method allows to take into account the trade-off between process variable and manipulated variable energy, thus overcoming one of the most important criticisms to Harris' index. </div>

scholarly journals Dual-hormone closed loop system using a liquid stable glucagon formulation versus insulin-only closed loop system compared to a predictive low glucose suspend system: an open label, outpatient, single center, crossover, randomized control trial

2020 ◽  
Author(s):  
Leah M. Wilson ◽  
Peter G. Jacobs ◽  
Katrina L. Ramsey ◽  
Navid Resalat ◽  
Ravi Reddy ◽  
...  
Keyword(s):  
Closed Loop ◽  
Artificial Pancreas ◽  
Loop System ◽  
Target Range ◽  
Closed Loop Control ◽  
Closed Loop System ◽  
Entire Study ◽  
Loop Control ◽  
Study Duration ◽  
Low Glucose

<b>Objective: </b>To assess the efficacy and feasibility of a dual-hormone closed loop system with insulin and a novel liquid stable glucagon formulation compared with an insulin-only closed loop system and a predictive low glucose suspend system. <p><b>Research Design and Methods:</b> In a 76-hour, randomized, crossover, outpatient study, 23 participants with type 1 diabetes used three modes of the Oregon Artificial Pancreas system: (1) dual-hormone (DH) closed loop control, (2) insulin-only single-hormone (SH) closed loop control and (3) predictive low glucose suspend (PLGS). The primary endpoint was percent time in hypoglycemia (<70 mg/dL) from start of in-clinic aerobic exercise (45mins at 60% VO<sub>2max</sub>) to 4 hours after.</p> <p><b>Results:</b> DH reduced hypoglycemia compared with SH during and after exercise (DH 0.0% [0.0-4.2], SH 8.3% [0.0-12.5], p=0.025). There was an increased time in hyperglycemia (>180mg/dL) during and after exercise for DH vs SH (20.8% DH vs. 6.3% SH, p=0.038). Mean glucose during the entire study duration was: DH 159.2, SH 151.6, PLGS 163.6 mg/dL. Across the entire study duration, DH resulted in 7.5% more time in target range (70-180 mg/dL) compared with the PLGS system (71.0% vs. 63.4%, p=0.044). For the entire study duration, DH had 28.2% time in hyperglycemia versus 25.1% for SH (p=0.044) and 34.7% for PLGS (p=0.140). Four participants experienced nausea related to glucagon leading 3 to withdraw from the study. </p> <p><b>Conclusions:</b> The glucagon formulation demonstrated feasibility in a closed loop system. The dual-hormone system reduced hypoglycemia during and after exercise with some increase in hyperglycemia.</p>

scholarly journals An Anti-Swing Closed-Loop Control Strategy for Overhead Cranes

2018 ◽  
Vol 8 (9) ◽  
pp. 1463 ◽  
Author(s):  
Xianghua Ma ◽  
Hanqiu Bao
Keyword(s):  
Control Strategy ◽  
Closed Loop ◽  
Working Environment ◽  
Underactuated System ◽  
Closed Loop Control ◽  
Overhead Crane ◽  
Closed Loop System ◽  
External Disturbances ◽  
Loop Control ◽  
Swing Angle

The payload swing of an overhead crane needs to be controlled properly to improve efficiency and avoid accidents. However, the swing angle is usually very difficult to control to zero degrees or for it to even remain within an acceptable range because the overhead crane is a complex nonlinear underactuated system, especially when the actual working environment is accompanied by strong disturbances and great uncertainty. To resolve this, a real-time anti-swing closed-loop control strategy is proposed that considers external disturbances. The swing angle is measured in time and it functions with the load displacement as feedback inputs of the closed-loop system. The nonlinear model of the crane is simplified by a linear system with virtual disturbances, which are estimated by the equivalent input disturbance (EID) method. Both simulation and experimental results for a 2-D overhead crane system are investigated to illustrate the validity of the proposed method.

scholarly journals Decentralised PI controller design based on dynamic interaction decoupling in the closed-loop behaviour of a flotation process

2021 ◽  
Vol 11 (6) ◽  
pp. 4865
Author(s):  
Nomzamo Tshemese-Mvandaba ◽  
R. Tzoneva ◽  
M. E. S. Mnguni
Keyword(s):  
Closed Loop ◽  
Controller Design ◽  
Design Procedure ◽  
Loop System ◽  
Closed Loop System ◽  
Flotation Process ◽  
Loop Control ◽  
Decoupling Method ◽  
Pi Controllers ◽  
Interconnected Model

An enhanced method for design of decenralised proportional integral (PI) controllers to control various variables of flotation columns is proposed. These columns are multivariable processes characterised by multiple interacting manipulated and controlled variables. The control of more than one variable is not an easy problem to solve as a change in a specific manipulated variable affects more than one controlled variable. Paper proposes an improved method for design of decentralized PI controllers through the introduction of decoupling of the interconnected model of the process. Decoupling the system model has proven to be an effective strategy to reduce the influence of the interactions in the closed-loop control and consistently to keep the system stable. The mathematical derivations and the algorithm of the design procedure are described in detail. The behaviour and performance of the closed-loop systems without and with the application of the decoupling method was investigated and compared through simulations in MATLAB/Simulink. The results show that the decouplers - based closed-loop system has better performance than the closed-loop system without decouplers. The highest improvement (2 to 50 times) is in the steady-state error and 1.2 to 7 times in the settling and rising time. Controllers can easily be implemented.

scholarly journals Realizing a Closed-Loop (Artificial Pancreas) System for the Treatment of Type 1 Diabetes

2019 ◽  
Vol 40 (6) ◽  
pp. 1521-1546 ◽  
Author(s):  
Rayhan A Lal ◽  
Laya Ekhlaspour ◽  
Korey Hood ◽  
Bruce Buckingham
Keyword(s):  
Type 1 Diabetes ◽  
Glucose Control ◽  
Closed Loop ◽  
Diabetes Management ◽  
Artificial Pancreas ◽  
Loop System ◽  
Closed Loop Control ◽  
Closed Loop System ◽  
Loop Control

Abstract Recent, rapid changes in the treatment of type 1 diabetes have allowed for commercialization of an “artificial pancreas” that is better described as a closed-loop controller of insulin delivery. This review presents the current state of closed-loop control systems and expected future developments with a discussion of the human factor issues in allowing automation of glucose control. The goal of these systems is to minimize or prevent both short-term and long-term complications from diabetes and to decrease the daily burden of managing diabetes. The closed-loop systems are generally very effective and safe at night, have allowed for improved sleep, and have decreased the burden of diabetes management overnight. However, there are still significant barriers to achieving excellent daytime glucose control while simultaneously decreasing the burden of daytime diabetes management. These systems use a subcutaneous continuous glucose sensor, an algorithm that accounts for the current glucose and rate of change of the glucose, and the amount of insulin that has already been delivered to safely deliver insulin to control hyperglycemia, while minimizing the risk of hypoglycemia. The future challenge will be to allow for full closed-loop control with minimal burden on the patient during the day, alleviating meal announcements, carbohydrate counting, alerts, and maintenance. The human factors involved with interfacing with a closed-loop system and allowing the system to take control of diabetes management are significant. It is important to find a balance between enthusiasm and realistic expectations and experiences with the closed-loop system.

scholarly journals Multi-criteria performance assessment based on closed-loop system identification

2021 ◽  
Author(s):  
Gustavo Sanchez
Keyword(s):  
System Identification ◽  
Closed Loop ◽  
Process Variable ◽  
Loop System ◽  
Closed Loop Control ◽  
Closed Loop System ◽  
Trade Off ◽  
Loop Control ◽  
Control Loops ◽  
Variable Energy

<div>A method to assess the performance of closed loop control loops, based on closed-loop system identification. This method allows to take into account the trade-off between process variable and manipulated variable energy, thus overcoming one of the most important criticisms to Harris' index. </div>

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