SET POINT AND IDENTIFIABILITY IN THE CLOSED LOOP WITH MINIMUM VARIANCE CONTROLLER11The paper was suported by Science Research Commitee grant No 3P 40301006

Background The Bispectral Index (BIS) is an electroencephalogram-derived measure of anesthetic depth. A closed-loop anesthesia system was built using BIS as the control variable, a proportional-integral-differential control algorithm, and a propofol target-controlled infusion system as the control actuator. Closed-loop performance was assessed in 10 adult patients. Methods Ten adult patients scheduled to undergo elective hip or knee surgery were enrolled. An epidural cannula was inserted, and 0.5% bupivacaine was used to provide anesthesia to T8 before general anesthesia was induced using the propofol target-controlled infusion system under manual control. After the start of surgery, when anesthesia was clinically adequate, automatic control of anesthesia was commenced using the BIS as the control variable. Adequacy of anesthesia during closed-loop control was assessed clinically and by calculating the median performance error, the median absolute performance error, and the mean offset of the control variable. Results The median performance error and the median absolute performance error were 2.2 and 8.0%, respectively. Mean offset of the BIS from the set point was 0.9. Cardiovascular parameters were stable during closed-loop control. Operating conditions were adequate in all patients but one, who began moving after 45 min of stable anesthesia. No patients reported awareness or recall of intraoperative events. In three patients, there was oscillation of the measured BIS around the set point. Conclusions The system was able to provide clinically adequate anesthesia in 9 of 10 patients. Further studies are required to determine whether control performance can be improved by alterations to the gain factors or by using an effect site-targeted, target-controlled infusion propofol system.

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Improved Glycemic Outcomes With Medtronic MiniMed Advanced Hybrid Closed-Loop Delivery: Results From a Randomized Crossover Trial Comparing Automated Insulin Delivery With Predictive Low Glucose Suspend in People With Type 1 Diabetes

10.2337/figshare.13618910 ◽

2021 ◽

Author(s):

Olivia J Collyns ◽

Renee A Meier ◽

Zara L Betts ◽

Denis SH Chan ◽

Chris Frampton ◽

...

Keyword(s):

Type 1 Diabetes ◽

Closed Loop ◽

Insulin Delivery ◽

Target Range ◽

Study Phase ◽

Pump Therapy ◽

Set Point ◽

Sensor Glucose ◽

Low Glucose

Objective: To study the MiniMed™ Advanced Hybrid Closed-Loop system (AHCL) which includes an algorithm with individualised basal target set points, automated correction bolus function, and improved Auto Mode stability. Research design and Methods: This dual-centre, randomized, open-label, two-sequence cross-over study in automated insulin delivery naïve participants with type 1 diabetes (aged 7-80yrs), compared AHCL to Sensor Augmented Pump therapy with Predictive Low Glucose Management (SAP+PLGM). Each study phase was 4 weeks, preceded by a 2-4 week run-in, and separated by 2-week washout. <a>Results: 59/60 people completed the study (mean age 23.3±14.4yrs). Time in target range (TIR) 3.9-10mmol/L (70-180 mg/dL) favoured AHCL over SAP+PLGM (</a>70.4±8.1 vs 57.9±11.7) by 12.5±8.5% (p<0.001), with greater improvement overnight (18.8±12.9%, p<0.001). All age groups (children (7 – 13 years), adolescents (14 – 21 years), and adults (>22 years) demonstrated improvement, with adolescents showing the largest improvement (14.4±8.4%). Mean sensor glucose (SG) at run in was 9.3±0.9 mmol/L (167±16.2mg/dL) and improved with AHCL (8.5±0.7mmol/L (153±12.6mg/dL) (p < 0.001)), but deteriorated during PLGM (9.5±1.1mmol/L (17±19.8mg/dL), (p<0.001)).. TIR was optimal when the algorithm set point was 5.6 mmol/L (100 mg/dL) compared to 6.7 mmol/L (120 mg/dL), 72.0±7.9% vs 64.6±6.9% respectively with no additional hypoglycemia. Auto Mode was active 96.4±4.0% of the time. <a>The percentage of hypoglycemia at baseline (<3.9mmol/L (70mg/dl) and </a> £ 3.0mmol/L(54mg/dl)) was 3.1±2.1% and 0.5±0.6% respectively. During AHCL percentage time <3.9mmol/L (70mg/dl) improved to 2.1±1.4% (p=0.034) (70mg/dl), and was statistically but not clinically reduced for £ 3.0mmol/L(54mg/dl) (0.5±0.5%, p = 0.025) There was one episode of mild diabetic ketoacidosis attributed to an infusion set failure in combination with an intercurrent illness, which occurred during the SAP+PLGM arm. Conclusions AHCL with automated correction bolus demonstrated significant improvement in glucose control compared to SAP+PLGM. A lower algorithm sensor glucose set point during AHCL resulted in greater TIR, with no increase in hypoglycemia.

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Set-Point Generation Using Kernel-Based Methods for Closed-Loop Combustion Control of a CIDI Engine

ASME 2009 Dynamic Systems and Control Conference, Volume 1 ◽

10.1115/dscc2009-2697 ◽

2009 ◽

Cited By ~ 2

Author(s):

Rajaram Maringanti ◽

Shawn Midlam-Mohler ◽

Ming Fang ◽

Fabio Chiara ◽

Marcello Canova

Keyword(s):

Steady State ◽

Degrees Of Freedom ◽

Closed Loop ◽

Exhaust Gas ◽

Loop Control ◽

Set Point ◽

Steady State Operation ◽

Engine Combustion ◽

Feedback Control Systems ◽

Homogenous Charge Compression Ignition

Closed-loop control of diesel combustion is of great interest for improving conventional Diesel engine combustion as well as facilitating new combustion modes such as Homogenous Charge Compression Ignition and other low NOx regimes. Most generalized feedback control systems that can be applied to this problem require a reference or set-point which the control attempts to achieve. Diesel engines are well known for having many degrees of freedom which poses a problem in generating valid set-points for all possible conditions encountered in practice. This problem is compounded by the fact that these set-points are usually determined in steady state operation further limiting the space where set-points can be defined. Kernel-based methods are applied to this problem as a method of generating valid setpoints when operating in regions outside of the space where set-points are defined. This is most useful during transient conditions where conditions such as exhaust gas recycle level, manifold air flow, and fuel mass are far from the steady state values.

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Data-driven minimum variance control using regulatory closed-loop data based on the FRIT method

Electronics and Communications in Japan ◽

10.1002/ecj.12156 ◽

2019 ◽

Vol 102 (4) ◽

pp. 28-34

Author(s):

Shogo Okada ◽

Shiro Masuda

Keyword(s):

Closed Loop ◽

Minimum Variance ◽

Data Driven ◽

Minimum Variance Control

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