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Friday 5 October 2018, 12h00 Lecture Hall D (James Watt)
Mekelweg 2
2628 CD DELFT
12h00 Stefhan van der Kemp, specialisation: MSD
Coaches: Prof.dr.ir. J.L. Herder, Ir. W.W.P.J. van de Sande
Title: Design of a compact wearable arm support utilizing shape
optimized shell mechanisms
Passive exoskeletons that support the weight of the surgeon’s arms could yield a significant ergonomic improvement in the laparoscopic theater. However, the cost and regulations associated with sterilization complicates adoption of such devices. In this work a compact passive arm support mechanism is designed that can be worn underneath the surgical gown to circumvent sterility requirements. The design utilizes shape optimized compliant shell mechanisms who’s geometry can remain close to the body as well as achieve the nonlinear stiffness characteristic that is desired for balancing the arm’s weight. A shell design with the desired torque-rotation characteristic is designed using shape optimization and fabricated for validation testing. Measurements show the prototype balances 19% of an average adult’s arm weight within ±4 percentage points between 0 and 90 degrees of arm abduction and or flexion. A prototype of the mechanism remains within 34mm of the arm, nearly twice as compact as the state of the art.
The presentation will be given in English.
12h20 Debate
12h30 End
Attending colloquia is an obligatory part of the curriculum of PME.
The presence of other people who are interested will be appreciated.
We are pleased to invite you to attend the PME-Final MSc presentation on:
Tuesday 9 October 2018, 12h45
Instruction room H
Mekelweg 2
2628 CD DELFT
12h45 Vincent Tedjawirja, specialisation: MSD
Coaches: Dr.ir. R.A.J. van Ostayen, Ir. J.W. Spronck
Title: Development of a low-cost radial bearing system
Air bearings are key elements for high precision systems. They enable a relative motion with low friction, no wear and retain a high stiffness. Within the high end CT-scanners of Royal Philips an air bearing system is used, to support a heavy rotating mechanism in the gantry. The current air bearing system, however, is expensive due to its large dimensions and strict tolerances. The air bearing system consists of a large sized ring, with radial air bearings as counter surface. The radial air bearings are supported by a suspension. This thesis focuses on the development of a low-cost radial air bearing system. The study has generated possible concepts of bearing systems, that potentially can reduce the costs. A feasibility study has been carried out on two selected bearing system concepts; many smaller air bearings and a combination of hovers and smaller air bearings. It turned out that the latter one is expected to have the highest potential on cost reduction. A refined theoretical and experimental investigation is carried out to determine the performance of the combination of hovers with smaller air bearings. It is shown, that this bearing concept is able to carry a static heavy load, while remaining a relatively high stiffness. Finally, a conceptual design of the low-cost radial air bearing system is proposed, which has the potential to cut costs by 17% with respect to the current design.
The presentation will be given in English.
13h05 Debate
13h15 End
Attending colloquia is an obligatory part of the curriculum of PME.
The presence of other people who are interested will be appreciated.
We are pleased to invite you to attend the PME-Final MSc presentation on:
Wednesday 31 October 2018, 09h30
Lecture Hall E (Robert Hooke)
Mekelweg 2
2628 CD DELFT
09h30 Erdi Akyüz, specialisation: MSD
Coaches: Ir. J.W. Spronck, Dr. S.H. Hossein Nia Kani
Title: Reset control for vibration isolation
High speeds and accelerations with nanometer accuracy are a necessity to meet the demands of the high-tech industry. However, immediate attention is needed towards rejecting floor vibrations, since they greatly affect the system performance. PID control is widely used in the industry to have good disturbance rejection. But, it is affected by Bode's gain phase relationship and waterbed effect. Reset control is a promising method to surpass the limitations of a linear controller. However, they are limited regarding disturbance rejection performance due to the controller introduced higher order harmonics that induces unwanted dynamics into the system. The aim of this thesis is to improve disturbance rejection through reset by looking at two different strategies to reduce higher order harmonics namely phase lag reduction and phase compensation. Band-pass reset control is proposed to overcome the negative effects that cause performance degradation as a phase reduction method. Results show phase compensation around the bandwidth is advantageous compared to phase reduction methods.
The presentation will be given in English.
09h50 Debate
10h00 End
Attending colloquia is an obligatory part of the curriculum of PME.
The presence of other people who are interested will be appreciated.
We are pleased to invite you to attend the PME-Final MSc presentation on:
Wednesday 31 October 2018, 13h00
Lecture Hall E (Robert Hooke)
Mekelweg 2
2628 CD DELFT
13h00 Yusuf Salman Haryadi, specialisation: MSD
Coaches: Ir. J.W. Spronck, Dr. S.H. Hossein Nia Kani
Title: Tuning a novel reset element through describing function and HOSIDF analysis
PID is the most used controller in the high-tech precision industry. However, PID suffers fundamental limitations of linear control and cannot achieve the industry increasing demand for faster and more precise system without sacrificing system stability and robustness. Reset control is a promising nonlinear control which can overcome the limitations and remains compatible to PID framework. This thesis focuses on a performance analysis and tuning of a novel reset element called 'Constant in Gain, Lead in Phase'(CgLp). Since its introduction, no guidelines available in the literature to design and tune this reset element. Looking at its potential as a new standard for industrial controller, a guideline to design CgLp is desired. Describing function which is commonly used to design reset element is insufficient since higher order harmonics which introduced by reset are not considered. The work in this thesis is performed by doing performance analysis of CgLp through describing function and an analysis tool for higher order harmonics visualization called HOSIDF. Based on the analysis, some basic tuning guidelines for designing controllers using CgLp is obtained.
The presentation will be given in English.
13h20 Debate
13h30 End
Attending colloquia is an obligatory part of the curriculum of PME.
The presence of other people who are interested will be appreciated.
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