Multivariable model predictive control of a pilot plant using Honeywell profit suite

This thesis documents the first implementation of Profit Suite into Murdoch University’s Pilot Plant. This Pilot Plant is a small scale model of the Bayer Alumina Process. Profit Suite is a Honeywell application that uses Model Predictive Control (MPC) for Multivariable Control (MVC). The major project objective was to connect Profit Suite to the exiting Experion PKS control system then compare multivariable model predictive control to the existing PI control scheme. The project objectives were achieved. Multivariable controllers were built that controlled temperatures and levels in both halves of the plant. The OPC connections between Profit Suite and Experion were completed and documented, as well as the procedures used to build and commission Profit Controllers in the Pilot Plant. Multivariable level controllers were designed using accurate models that performed well. These MVCs performed better than PI control in that they managed all tank levels and recycle streams throughout the plant. Linear objective functions were used to optimize flows and levels with success. Baseline testing of the PI Controllers showed they were better than the MVCs for temperature control. The steam pressure disturbance had no effect on temperatures controlled by fast executing Experion PI controllers. Models found for steam pressure caused MVCs to overcompensate for this temperature disturbance. An MVC built that could manipulate steam valve positions to control temperature performed poorly compared to PI control. Multivariable temperature control was significantly improved when all pumps and steam valves were used as Manipulated Variables by the MVC. Models between water flow rates and temperatures enabled the MVC to use additional pump MVs to counteract the steam pressure disturbance. There was no existing instrumentation to measure steam flowrates from each valve. This required Profit Suite to connect to the OP point of the PI Controllers to directly manipulate valve position for temperature control. Temperature control by cascaded PI steam flow control is recommended to improve the performance of multivariable temperature control. The installation of steam flow transmitters will enable the set point of a PI flow controller to be used as an MV by Profit Control. Fundamental models between steam flowrates and tank temperatures could then be acquired for multivariable control

INFLUENCE OF BODY SEGMENT INERTIA PARAMETERS ON UNCERTAINTIES IN JOINT SPECIFIC POWER DURING SPRINT CYCLING: A MONTE CARLO SIMULATION

Joint-specific power analyses are important in the assessment of cycling biomechanics but they contain uncertainties due to errors in input parameters. The aim of the study was to investigate the effect of uncertainty in body segment parameters on joint-specific powers during maximal sprint cycling, using a Monte Carlo analysis. Joint powers were estimated using standard inverse dynamics techniques, with body segment parameters and uncertainty in these inputs defined using reference data. Monte Carlo simulations (10,000 iterations) were performed for pedal cycles at 120 rpm and 160 rpm. The analysis highlighted practically relevant uncertainties in peak hip joint power at racespecific pedalling rates caused by uncertainty in body segment parameters

THE INFLUENCE OF CLUB SHAFT CHARACTERISTICS ON THE HIP-SHOULDER SEPARATION ANGLE DURING THE GOLF DRIVE

The way in which club head speed is generated during the golf swing has often been explained using the 'double pendulum model' (e.g. Budney and Bellow, 1992). However, recent research has suggested that club head speed generation is related to the separation angle between transverse plane hip and shoulder rotations (e.g. Cheetham et aI., 2001). It is possible that the shaft characteristics of golf drivers may affect swing mechanics and alter the magnitude of the hip-shoulder separation angle. Generally, it is now recognised that single-individual designs are valuable in sports science research (Bates, 1996). The purpose of this preliminary study was to investigate the effect of club shaft characteristics on the hipshoulder separation angle during the golf drive using a single-individual desig

ACUTE EFFECT OF TEXTURED INSOLES ON BIOMECHANICS OF MAXIMAL CYCLING

The aim of the study was to investigate whether a within-session intervention of textured insoles worn in participants cycling shoes altered maximal cycling power output and biomechanics. Ten track sprint cyclists performed sprints on an isokinetic ergometer with and without textured insoles. Key biomechanical variables (crank kinetics, joint kinematics and kinetics) characterising sprint cycling were measured. There was a significant reduction in average crank power for the sprints performed with the textured insoles (P = 0.029) potentially associated with the reported discomfort when using the textured insoles. There were no changes in any other biomechanical measures suggesting a textured insoles intervention may have little impact on maximal cycling performance

Literature Review and Case Histories of Histoplasma capsulatum var. duboisii Infections in HIV-infected Patients

African histoplasmosis during HIV infection is rare

Reliability and validity of depth camera 3D scanning to determine thigh volume

Gross thigh volume is a key anthropometric variable to predict sport performance and health. Currently, it is either estimated by using the frustum method, which is prone to high inter-and intra-observer error, or using medical imaging, which is expensive and time consuming. Depth camera 3D-imaging systems offer a cheap alternative to measure thigh volume but no between-session reliability or comparison to medical imaging has been made. This experiment established between-session reliability and examined agreement with magnetic resonance imaging (MRI). Forty-eight male cyclists had their thigh volume measured by the depth camera system on two occasions to establish between-session reliability. A subset of 32 participants also had lower body MRIs, through which agreement between the depth camera system and MRI was established. The results showed low between-session variability (CV = 1.7%; Absolute Typical Error = 112 cm3) when measuring thigh volume using the depth camera system. The depth camera systematically measured gross thigh volume 32.6cm3 lower than MRI. These results suggest that depth camera 3D-imaging systems are reliable tools for measuring thigh volume and show good agreement with MRI scanners, providing a cheap and time-saving alternative to medical imaging analysis

Biomechanical measures of short-term maximal cycling on an ergometer: a test-retest study.

An understanding of test-retest reliability is important for biomechanists, such as when assessing the longitudinal effect of training or equipment interventions. Our aim was to quantify the test-retest reliability of biomechanical variables measured during short-term maximal cycling. Fourteen track sprint cyclists performed 3 × 4 s seated sprints at 135 rpm on an isokinetic ergometer, repeating the session 7.6 ± 2.5 days later. Joint moments were calculated via inverse dynamics, using pedal forces and limb kinematics. EMG activity was measured for 9 lower limb muscles. Reliability was explored by quantifying systematic and random differences within- and between-session. Within-session reliability was better than between-sessions reliability. The test-retest reliability level was typically moderate to excellent for the biomechanical variables that describe maximal cycling. However, some variables, such as peak knee flexion moment and maximum hip joint power, demonstrated lower reliability, indicating that care needs to be taken when using these variables to evaluate biomechanical changes. Although measurement error (instrumentation error, anatomical marker misplacement, soft tissue artefacts) can explain some of our reliability observations, we speculate that biological variability may also be a contributor to the lower repeatability observed in several variables including ineffective crank force, ankle kinematics and hamstring muscles' activation patterns

Effects of strength training on the biomechanics and coordination of short-term maximal cycling.

The aim was to investigate the effects of a gym-based strength training intervention on biomechanics and intermuscular coordination patterns during short-term maximal cycling. Twelve track sprint cyclists performed 3 × 4 s seated sprints at 135 rpm, interspersed with 2 × 4 s seated sprints at 60 rpm on an isokinetic ergometer, repeating the session 11.6 ± 1.4 weeks later following a training programme that included two gym-based strength training sessions per week. Joint moments were calculated via inverse dynamics, using pedal forces and limb kinematics. EMG activity was measured for 9 lower limb muscles. Track cyclists 'leg strength" increased (7.6 ± 11.9 kg, P = 0.050 and ES = 0.26) following the strength training intervention. This was accompanied by a significant increase in crank power over a complete revolution for sprints at 135 rpm (26.5 ± 36.2 W, P = 0.028 and ES = 0.29). The increase in leg strength and average crank power was associated with a change in biceps femoris muscle activity, indicating that the riders successfully adapted their intermuscular coordination patterns to accommodate the changes in personal constraints to increase crank power