Novel Methods for Error Modeling and Parameter Identification of a Redundant Serial-Parallel Hybrid Robot

To obtain the desirable accuracy of a robot, there are two techniques available. The first option would be to make the robot match the nominal mathematic model. In other words, the manufacturing and assembling tolerances of every part would be extremely tight so that all of the various parameters would match the “design” or “nominal” values as closely as possible. This method can satisfy most of the accuracy requirements， but the cost would increase dramatically as the accuracy requirement increases. Alternatively, a more cost-effective solution is to build a manipulator with relaxed manufacturing and assembling tolerances. By modifying the mathematical model in the controller, the actual errors of the robot can be compensated. This is the essence of robot calibration. Simply put, robot calibration is the process of defining an appropriate error model and then identifying the various parameter errors that make the error model match the robot as closely as possible. This work focuses on kinematic calibration of a 10 degree-of-freedom (DOF) redundant serial-parallel hybrid robot. The robot consists of a 4-DOF serial mechanism and a 6-DOF hexapod parallel manipulator. The redundant 4-DOF serial structure is used to enlarge workspace and the 6-DOF hexapod manipulator is used to provide high load capabilities and stiffness for the whole structure. The main objective of the study is to develop a suitable calibration method to improve the accuracy of the redundant serial-parallel hybrid robot. To this end, a Denavit–Hartenberg (DH) hybrid error model and a Product-of-Exponential (POE) error model are developed for error modeling of the proposed robot. Furthermore, two kinds of global optimization methods, i.e. the differential-evolution (DE) algorithm and the Markov Chain Monte Carlo (MCMC) algorithm, are employed to identify the parameter errors of the derived error model. A measurement method based on a 3-2-1 wire-based pose estimation system is proposed and implemented in a Solidworks environment to simulate the real experimental validations. Numerical simulations and Solidworks prototype-model validations are carried out on the hybrid robot to verify the effectiveness, accuracy and robustness of the calibration algorithms.

Acquisition target selection of a serial acquirer : case KONE Oyj

Acquisitions are a way for a company to grow, enter new geographical areas, buy out competition or diversify. Acquisitions have recently grown in both size and value. Despite of this, only approximately 25 percent of acquisitions reach their targets and goals. Companies making serial acquisitions seem to be exceptionally successful and succeed in the majority of their acquisitions. The main research question this study aims to answer is: “What issues impact the selection of acquired companies from the point of view of a serial acquirer? The main research question is answered through three sub questions: “What is a buying process for a serial acquirer like?”, “What are the motives for a serial acquirer to buy companies?” and “What is the connection between company strategy and serial acquisitions?”. The case company KONE is a globally operating company which mainly produces and maintains elevators and escalators. Its headquarter is located in Helsinki, Finland. The company has a long history of making acquisitions and does 20- 30 acquisitions a year. By a key person interview, the acquisition process of the case company is compared with the literature about successful serial acquirers. The acquisition motives in this case are reflected upon three of the acquisition motive theories by Trautwein: efficiency theory, monopoly theory and valuation theory. The linkage between serial acquisitions and company strategy is studied through the key person interview. The main research findings are that the acquisition process of KONE is compatible with a successful acquisition process recognized in literature (RAID). This study confirms the efficiency theory as an acquisition motive and more closely the operational synergies. The monopoly theory can only vaguely be supported by this study, but cannot be totally rejected because of the structure of the industry. The valuation theory does not get any support in this study and can therefore be rejected. The linkage between company strategy and serial acquisitions is obvious and making acquisitions can be seen as growth strategy and a part of other company strategies.

Separating deviant and non-deviant sexual preferences with a dual-target rapid serial visual presentation task

Forskning visar att avvikande sexuell preferens (ASP) är en av de mest centrala prediktorerna för återfall i sexualbrott. Eftersom det är viktigt att det i juridiskt beslutsfattande och behandling av sexualförbrytare finns valida och standardiserade verktyg att tillgå för bedömning av ASP, har forskningen under de senaste åren fokuserats på uppmärksamhetsbaserade metoder. Syftet med avhandlingen var att förbättra uppmärksamhetsbaserade metoder genom utvecklingen av en s.k. Rapid Serial Visual Presentation (dtRSVP) metod för att identifiera ASP. Innan vi testade sampel med sexualbrottslingar så genomförde vi tre studier för att kalibrera förfarandena. I dessa studier undersökte vi möjligheten att differentiera mellan homosexuella och heterosexuella män och hur enkelt deltagarna kunde fuska. Dessutom skapade vi en ny uppsättning standardiserade stimuli för bedömningen av pedofilt sexuellt intresse (Virtual People Set, VPS). I skapandet av stimuli togs de etiska och juridiska problemen i beaktande så långt som möjligt. När vi använde dtRSVP som mätningsförfarande för att skilja åt sexuellläggning i ett sampel av homosexuella och heterosexuella män fann vi att sexuellt relevanta stimuli påverkade informationsbehandlingen på ett förutsägbart sätt. Förfarandet hade en god förmåga att skilja sexuella preferenser mellan grupperna och förfarandet var svårt att påverka genom att fuska. När vi använde dtRSVP som mätningsförfarande för att identifiera avvikande sexuell läggning bland dömda sexbrottslingar fann vi att de visade en annorlunda bearbetning av sexuella stimuli jämfört med andra deltagare och att dessa skillnader var i de förväntade riktningarna. Det var däremot svårt att dra några slutsatser angående denna mätmetods förmåga att skilja mellan grupperna pedofiler och icke-pedofiler. Slutligen fann vi att VPS verkar vara ett användbart stimuluspaket för experimentell forskning om pedofilt sexuellt intresse. ---------------------------------------------------- Tutkimuksien mukaan poikkeava seksuaalinen mieltymys (PSM) on yksi seksuaalirikoksen uusimisen keskeisimmistä ennustajista. Oikeudellisessa päätöksenteossa ja seksuaalirikollisten hoidossa on tärkeää, että on käytettävissä kelvollisia ja standardisoituja välineitä PSM:n arvioinnissa. Sen vuoksi on tutkimuksissa viime vuosina keskitytty huomaavaisuuteen perustuviin menetelmiin. Tämän tutkielman tarkoitus oli parantaa huomaavaisuuteen perustuvia menetelmiä kehittämällä nk. Rapid Serial Visual Presentation (dtRSVP) menetelmän. Kalibroidakseen menettelytapoja suoritettiin kolme tutkimusta ennen kuin tutkittiin koeryhmää, johon kuuluvat seksuaalirikollisia. Näissä tutkimuksissa tutkittiin mahdollisuutta erotella homoseksuaalisia ja heteroseksuaalisia miehiä ja tutkittiin missä määrin osallistujien oli helppo huiputtaa. Sen lisäksi, pedofiilisen seksuaalisen mieltymyksen arviointia varten kehitettiin uutta sarjaa standardisoituja virikkeitä (Virtual People Set, VPS). Kehitettäessä virikkeitä otettiin mahdollisimman pitkälti huomioon eettisiä ja oikeudellisia ongelmia. Käytettäessä dtRSVP mittausmenetelmää erotellakseen homo- ja heteroseksuaalista suuntautumista havaitsimme, että seksuaaliset virikkeet vaikuttivat tietojenkäsittelyyn ennustettavalla tavalla. Menettelytavan avulla pystyttiin erotella koeryhmässä olevia seksuaalisia mieltymyksiä ja menettelytapaan oli vaikeaa vaikuttaa huijaamalla. Käytettäessä dtRSVP mittausmenetelmää tunnistaakseen poikkeavaa seksuaalista mieltymystä tuomittujen seksuaalirikollisten keskenään havaitsimme, että he osoittivat erilaista käsittelyä seksuaalisista virikkeistä toisiin osallistujiin verrattuna ja tulokset olivat ennustettavia. Silti oli vaikeaa tehdä johtopäätöksiä mittausmenetelmän kyvystä erotella ryhmiä pedofiilisiä ja ei-pedofiilisiä miehiä. Lopuksi havaitsimme, että VPS näyttää olevan käyttökelpoinen stimulussarja pedofiilisen seksuaalisen mieltymyksen kokeellisissa tutkimuksissa.

Relay card for capacitance measurements

In this bachelor's thesis a relay card for capacitance measurements was designed, built and tested. The study was made for the research and development laboratory of VTI Technologies, which manufactures capacitive silicon micro electro mechanical accelerometers and pressure sensors. As the size of the sensors is decreasing the capacitance value of the sensors also decreases. The decreased capacitance causes a need for new and more accurate measurement systems. The technology used in the instrument measuring the capacitance dictates a framework how the relay card should be designed, thus the operating principle of the instrument must be known. To achieve accurate results the measurement instrument and its functions needed to be used correctly. The relay card was designed using printed circuit board design methods that minimize interference coupling to the measurement. The relay card that was designed in this study is modular. It consists of a separate CPU card, which was used to control the add-on cards connected to it. The CPU card was controlled from a computer through a serial bus. Two add-on cards for the CPU card were designed in this study. The first one was the measurement card, which could be used to measure 32 capacitive sensors. The second add-on card was the MUX card, which could be used to switch between two measurement cards. The capacitance measurements carried out through the MUX card and the measurement cards were characterized with a series of test measurements. The test measurement data was then analysed. The relay card design was confirmed to work and offer accurate measurement results up to a measurement frequency of 10 MHz. The length of the measurement cables limited the measurement frequency.