Forestry machines have the power to lift heavy logs, but they are not so smart at providing information, or help operators perform better work. The main reason to this problem is the low level of technology applied to forestry machines, which has not changed so much since the forestry machines were first introduced in the 1960’s. But starting 2013, machines manufacturers got inspired by developments in the automation and robotics industry, several of new technologies have been developed in the market - computerized hydraulics, feedback controllers for vibration damping, sensor-based motion control systems, improvements in mechanical design, smart suspension controller, etc. Largely, this development is attributed to better hardware and software developed during the last decade by researchers of Scandinavian institutes. In this thesis, we introduce a new type of forestry machine, the harwarder, which can perform the work of two machines (harvester and forwarder) by a single one. The forwarder is a forestry vehicle that carries big felled logs. The harvester is a type of heavy forestry manipulator employed in cut-to-length logging operations for felling, and bucking trees. Both the manipulator and vehicle should work synchronized to get the best out of this design. To benefit out of its design, in the first part of thesis we will analyze the kinematics and dynamics of machine, and design a time optimal coordinated motion via virtual holonomic constraints, to solve a particular task of forestry crane. The second part consists on applying optimization to reduce energy consumption during the motion. Result of thesis work: 1) By using coordinated motion, consequently the energy consumptions are drastically reduced comparing to traditional motion of the crane. 2) By applying optimization, the energy efficiency is improved.

<p>In the field of robotics there is a great interest in developing strategies and algorithms to reproduce human-like behavior. One can think of human-like machines that may replace humans in hazardous working areas, perform enduring assembly tasks, serve the elderly and handicapped, etc. The main challenges in the development of such robots are, first, to construct sophisticated electro-mechanical humanoids and, second, to plan and control human-like motor patterns.</p><p>A promising idea for motion planning and control is to reparameterize any somewhat coordinated motion in terms of virtual holonomic constraints, i.e. trajectories of all degrees of freedom of the mechanical system are described by geometric relations among the generalized coordinates. Imposing such virtual holonomic constraints on the system dynamics allows to generate synchronized motor patterns by feedback control. In fact, there exist consistent geometric relations in ordinary human movements that can be used advantageously. In this thesis the virtual constraints approach is extended to a wider and rigorous use for analyzing, planning and reproducing human-like motions based on mathematical tools previously utilized for very particular control problems.</p><p>It is often the case that some desired motions cannot be achieved by the robot due to limitations in available actuation power. This constraint rises the question of how to modify the mechanical design in order to achieve better performance. An underactuated planar two-link robot is used to demonstrate that springs can complement the actuation in parallel to an ordinary motor. Motion planning is carried out for the original robot dynamics while the springs are treated as part of the control action with a torque profile suited to the preplanned trajectory.</p><p>Another issue discussed in this thesis is to find stable and unstable (hybrid) limit cycles for passive dynamic walking robots without integrating the full set of differential equations. Such procedure is demonstrated for the compass-gait biped by means of optimization with a reduced number of initial conditions and parameters to search. The properties of virtual constraints and reduced dynamics are exploited to solve this problem.</p>

Whether it is a car, a mobile phone, or a computer, we are noticing how automation and production with robots plays an important role in the industry of our modern world. We find it in factories, manufacturing products, automotive cruise control, construction equipment, autopilot on airplanes, and countless other industrial applications.         Automation technology can vary greatly depending on the field of application. On one end, we have systems that are operated by the user and rely fully on human ability. Examples of these are heavy-mobile equipment, remote controlled systems, helicopters, and many more. On the other end, we have autonomous systems that are able to make algorithmic decisions independently of the user.         Society has always envisioned robots with the full capabilities of humans. However, we should envision applications that will help us increase productivity and improve our quality of life through human-robot collaboration. The questions we should be asking are: “What tasks should be automated?'', and “How can we combine the best of both humans and automation?”. This thinking leads to the idea of developing systems with some level of autonomy, where the intelligence is shared between the user and the system. Reasonably, the computerized intelligence and decision making would be designed according to mathematical algorithms and control rules.         This thesis considers these topics and shows the importance of fundamental mathematics and control design to develop automated systems that can execute desired tasks. All of this work is based on some of the most modern concepts in the subjects of robotics and control, which are synthesized by a method known as the Virtual Holonomic Constraints Approach. This method has been useful to tackle some of the most complex problems of nonlinear control, and has enabled the possibility to approach challenging academic and industrial problems. This thesis shows concepts of system modeling, control design, motion analysis, motion planning, and many other interesting subjects, which can be treated effectively through analytical methods. The use of mathematical approaches allows performing computer simulations that also lead to direct practical implementations.

In the field of robotics there is a great interest in developing strategies and algorithms to reproduce human-like behavior. One can think of human-like machines that may replace humans in hazardous working areas, perform enduring assembly tasks, serve the elderly and handicapped, etc. The main challenges in the development of such robots are, first, to construct sophisticated electro-mechanical humanoids and, second, to plan and control human-like motor patterns. A promising idea for motion planning and control is to reparameterize any somewhat coordinated motion in terms of virtual holonomic constraints, i.e. trajectories of all degrees of freedom of the mechanical system are described by geometric relations among the generalized coordinates. Imposing such virtual holonomic constraints on the system dynamics allows to generate synchronized motor patterns by feedback control. In fact, there exist consistent geometric relations in ordinary human movements that can be used advantageously. In this thesis the virtual constraints approach is extended to a wider and rigorous use for analyzing, planning and reproducing human-like motions based on mathematical tools previously utilized for very particular control problems. It is often the case that some desired motions cannot be achieved by the robot due to limitations in available actuation power. This constraint rises the question of how to modify the mechanical design in order to achieve better performance. An underactuated planar two-link robot is used to demonstrate that springs can complement the actuation in parallel to an ordinary motor. Motion planning is carried out for the original robot dynamics while the springs are treated as part of the control action with a torque profile suited to the preplanned trajectory. Another issue discussed in this thesis is to find stable and unstable (hybrid) limit cycles for passive dynamic walking robots without integrating the full set of differential equations. Such procedure is demonstrated for the compass-gait biped by means of optimization with a reduced number of initial conditions and parameters to search. The properties of virtual constraints and reduced dynamics are exploited to solve this problem.

The thesis deals with the path planning and movement of the holonomic robot in a dynamic environment. The aim of this work is implementation of several algorithms based on Rapidly-explored random tree algorithm and their comparison in designed dynamic environment.

A three-level system can be used in a Λ-type configuration in order to construct auniversal set of non-adiabatic quantum gates through the use of non-Abelian non-adiabatic geometrical phases. Such construction allows for high-speed operation times which diminish the effects of decoherence. This might be, however, accompanied by a breakdown of the validity of the rotating wave approximation (RWA) due to the comparable timescale between the counter-rotating terms and the pulse length, which greatly affects the dynamics. Here we investigate the trade-off between dissipative effects and the RWA validity, obtaining the optimal regime for the operation of the holonomic quantum gates.

A Displacement Based Optimization (DBO) approach was applied to truss design problems with material nonlinearities, to explore feasibility and verify efficiency of the approach to solve such problem. Various truss sizing problems with holonomic (path-independent) elastoplastic laws were investigated. This type of material nonlinearity allows us to naturally extend the linear elastic truss sizing in the DBO setting to nonlinear problems. A computer program that uses the commercially available optimizer DOT by VR&D and IMSL Linear Programming solver by Visual Numerics was developed to solve this type of problems. For comparison, we chose an important class of minimum-weight truss design problems, where holonomic linear strain hardening behavior was used. Additional examples of optimum design of trusses with elastic perfectly plastic material response that could be easily solved by Limit Design approach using linear programming were investigated for comparison. All demonstrated examples were tested successfully using the DBO approach. Solutions of comparable examples were consistent with the available results by other methods. Computational effort associated with the DBO approach was minimal for all the examples studied. Optimum solutions of several examples proved that the DBO approach is particularly suited for truss topology design where removal of truss members is essential. / Master of Science

Quantum holonomies are non-Abelian Geometric Phases predominantly observed in adiabatic, non-adiabatic, or measurement-based quantum evolutions. Their significance lies in their potential utility within quantum computing due to their robustness against noise throughout the parameter path. In this report, we detail the foundational methods necessary for constructing holonomic non-Abelian gates specifically designed for tripartite states <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?%7CW%3E" data-classname="equation" data-title="" />and <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?%7C%5Cbar%7BW%7D%3E" data-classname="equation" data-title="" />, which serve as the logical qubits in our project. Given that the existence of a universal set of gates has already been demonstrated for each of these evolution types, our project delves into the advantages of applying these basis states across the three evolution categories. We have reformulated the Nuclear Quadrupole Resonance (NQR) Hamiltonian to be exclusively composed of two-body terms, thus rendering it more experimentally feasible. Furthermore, we have connected the W states with the remaining tripartite states to construct a four-level model system and generalized gates within this framework. Lastly, we introduce a measurement-based method that maintains its non-Abelian attributes even in the Zeno limit, where the process of projective measurement gradually approaches the adiabatic model. / Icke-Abelska geometriska faser, så kallade kvantholonomier, observeras huvudsakligen i adiabatiska, icke-adiabatiska eller mätningsbaserade manipulationer av kvanttillstånd. De har stor potential till användning inom kvantdatorberäkningar på grund av deras robusthet mot olika typer av brus. I den här rapporten beskriver vi de grundläggande metoderna som är nödvändiga för att konstruera holonoma kvantgrindar som är speciellt utformade för trekroppstillstånden <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?%7CW%3E" data-classname="equation" /> och <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?%7C%5Cbar%7BW%7D%3E" data-classname="equation" data-title="" />, som fungerar som de logiska kvantbitarna i projektet, givet att det är redan bevisat att alla dessa modeller kan klara kraven för universalitet. Den här rapporten fokuserar på fördelarna med att tillämpa dessa logiska kvantbitar för tre olika evolutionskategorier. Vi har omformulerat kärnkvadrupolresonans Hamiltonianen så att den uteslutande består av tvåkroppstermer, vilket gör den mer experimentellt genomförbar för att realisera adiabatiska holonoma kvantgrindar. Vidare har vi kopplat <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?W" data-classname="equation" data-title="" />-tillstånden med andra trekroppstillstånden för att konstruera ett så kallat sammanflätat <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?%5CLambda" data-classname="equation" data-title="" />-system och icke-adiabatiska holonoma kvantgrindar inom detta ramverk. Slutligen introducerar vi en mätningsbaserad metod som, till skillnad från tidigare resultat, bibehåller sina icke-Abelska attribut även i Zeno-gränsen, där processen med projektiv mätning gradvis närmar sig den adiabatiska kärnkvadrupolresonans-modellen.

Automated guided vehicles (AGV) are more and more used in factories to provide a smart and adaptable material handling based on localization technologies. To use vision and path finding technologies at their full potential in these vehicles, a mechanical system able to move within a small space is required. The purpose of this study was to develop the mechanical structure of an AGV. The structure is composed of a chassis and mecanum wheels. To satisfy the needs, the vehicle had to be able to carry heavy loads while being compact. It also had to be cheap to be competitive on the market. Calculation models were developed to design mecanum wheels. From these models, the structure of the vehicle has been designed. The obtained solution fulfils requirements and solves some problems encountered by the previous design of the vehicle. However the prototype haven’t be fully tested due to manufacturing problems on rollers. This study offers a strong basis to design an AGV and points out common problems related to the design of a holonomic vehicle. Furthermore, some of the solutions proposed in this study need to be tested for validation. / Automatiskt styrda fordon, AGV, används allt mer i fabriker för att ge en smart och anpassningsbar materialhantering baseratdpå lokaliseringsteknik. För att möjliggöra användande av visions- och vägspårningsteknologi till dess rätta potential för automatiskt styrda fordon behövs ett mekaniskt system som kan röra sig på små ytor. Syftet med studien har varit att utveckla den mekaniska strukturen till en AGV. Strukturen består av ett chassi och mecanumhjul. För att uppfylla behovet, måste fordonet kunna bära stora laster samtidigt som det ska vara kompakt. Det krävdes även att den skulle vara billig för att vara konkurrenskraftig på marknaden. Beräkningsmodeller har tagits fram för att möjliggöra utformning av mecanumhjulen. Den hjul- och chassiutformning som tagits fram uppfyller krav som löser problem i föregående utformningar. Prototypen har dock ej blivit fullt testad på grund av tillverkningsproblem av rullarna. Studien har givit en stark bas för utformning av AGV och pekar ut vanliga problem relaterade till utformandet av holonomiska fordon. Lösningarna som presenterats i denna studie behöver testas för att validera utformningen.

This thesis investigates the strengths and weaknesses of omnidirectional drive and differential drive systems on mobile manipulator robots. Based on a literature study, a hypothetical use case, and identified Key Performace Indicators the drive system’s effects on the performance of the mobile manipulator are evaluated. A qualitative approach was used for evaluation. The research methodology involved analyzing the wheel characteristics of each drive system, identifying parameters affecting the performance, and assessing the two drive system characteristics within the context of the hypothetical use case. Six Key Performance Indicators such as pose accuracy, space utilization, and manipulability were formulated and examined to determine the comparative strengths and weaknesses of the drive systems. The results confirmed that omnidirectional drive systems exhibit greater maneuverability and agility while differential drive systems are less complex and often more durable in rough conditions. However, the results also show that in many cases the answer on what drive system to use will depend on many factors and that these factors can affect the overall performance of the mobile manipulator. This study provides insights into performance-affecting parameters and relevant performance aspects by examining the strengths and weaknesses of omnidirectional and differential drive systems. While acknowledging the need for caution in generalizing the findings and assuming validity in real-world applications, the results obtained serve as a starting point for further investigations. / Detta examensarbete undersöker styrkor och svagheter hos omnidirektionella drivsystem och differentialdrivsystem på mobila manipulatorer. En kvalitativ metod, baserat på en litteraturstudie, ett hypotetiskt användningsscenario och identifierade prestationsindikatorer, användes för att utvärdera drivsystemets effekter på den mobila manipulatorns prestanda. Forskningsmetodiken innebar att analysera hjulegenskaperna för varje drivsystem, identifiera parametrar som påverkar prestandan och bedöma de två drivsystemens egenskaper inom ramen för det hypotetiska användningsfallet. Viktiga prestationsindikatorer som poserings noggrannhet, utrymmesutnyttjande och manipulerbarhet undersöktes för att fastställa och jämförande styrkorna och svagheterna hos drivsystemen. Resultaten bekräftade att omnidirektionella drivsystem uppvisar större manövrerbarhet och smidighet medan differentialdrivsystem ofta är mindre komplexa och mer hållbara under tuffa förhållanden. Dock visar resultaten även att svaret på vilket drivsystem som ska användas i många fall beror på flertalet faktorer och att dessa faktorer kan påverka den mobila manipulatorns totala prestanda. Denna studie ger insikter i prestandapåverkande parametrar och relevanta prestandaaspekter genom att undersöka styrkorna och svagheterna hos omnidirektionella och differentiella drivsystem. Samtidigt som man erkänner behovet av försiktighet med att generalisera resultaten och anta giltighet i verkliga tillämpningar, tjänar de erhållna resultaten som en utgångspunkt för ytterligare undersökningar.