This Thesis has been carried out as a final part of the Mechanical Engineering programme (180 credits) at Karlstad University during the spring semester 2022 and comprises 22.5 credits. The work is carried out on behalf of Valmet AB in Karlstad.At the beginning of a tissue machine, a mixture of fibres and water is fed into the machine and formed into a sheet using a forming wire and felt. During maintenance work, the wire sometimes needs to be detached from the machine. In order to release the forming wire, the breast roll retraction system needs to be opened up, which is done using an arm with the breast roll attached to it. This arm can rotate upwards, taking the breast roll with it, and when this is opened, the forming wire can be removed. In the hinge that this arm is attached to there is a gap, in addition to the gap the arm can be bent slightly. When the arm is returned to its original position after replacing of the forming wire, this gap and bending creates some problems. The problem is that the arm needs to return to its original position with great precision to avoid unnecessary adjustments. This is currently done using keys with angled walls and to lock the position eye bolts with associated nuts. The manufacturing of this solution has been identified as expensive due to tight tolerances and the angled walls of the keys and keyways. The aim of this project is to make the design cheaper to manufacture through design modification of this positioning and locking mechanism.Through a feasibility study regarding the current design and manufacturing method a deeper understanding of the function and machining was gained. The project has followed a structured product development process, from pre-study through requirements specification, concept generation and evaluation to detailed design. A requirement specification was developed using the results of the feasibility study together with information from Valmet employees. Two concept generation sessions were conducted, the 6-3-5 method and morphological matrix, these were done together with people at Valmet with different experiences. For concept evaluation and selection, Harris profile and relative decision matrix were used, these were conducted after consultation with experienced people at Valmet.The best concept is a design change that eliminates the milled angled walls in the keyway on the arm. These are replaced by a cylindrical pocket and a threaded hole. A corresponding change is made to the bracket against which the arm rests. Instead of the keys used today, two turned parts with a conical contact surface between them are proposed. This solution achieves all the requirements of the requirements specification as well as all the wishes except that it should fit similar fastening elements in other sections of the machine. The explanation for this is that the other fastening elements have slightly different functions which the proposed solution does not take into account. The price difference between the current design and the design proposed by the project has been obtained by a subcontractor providing price proposals for both. / Detta Examensarbete har genomförts som en avslutande del av maskiningenjörsutbildningen (180 hp) vid Karlstads universitet under vårterminen 2022 och omfattar 22.5 hp. Arbetet utförs på uppdrag av Valmet AB i Karlstad. I början av en tissuemaskin förs en blandning av fibrer och vatten in i maskinen och formas till ett ark med hjälp av en vira och filt. Vid underhållsarbete behöver viran ibland tas ut från maskinen. För att lossa viran behöver bröstvalsen öppnas upp, detta görs genom att bröstvalsen sitter fastspänd på en arm. Denna arm kan rotera upp och tar då med sig bröstvalsen, när denna är öppnad så kan viran tas ut. I gångjärnet som denna arm sitter på finns ett glapp, förutom glappet kan armen böjas något. När armen, efter att viran bytts ut, ska återgå till sitt ursprungliga läge skapar detta glapp och böjning viss problematik. Problemet är att armen behöver återgå till sitt ursprungliga läge med stor precision för att undvika onödiga justeringar. Detta görs idag med hjälp av kilar med vinklade väggar samt för att låsa fast positionen fäll skruvar med tillhörande mutter. Tillverkningen av denna lösning har identifierats som dyr på grund av snäva toleranser och de vinklade väggarna på kilen och kilspåret. Syftet med detta projekt är att genom designändring av denna positionering och låsningsmekanism få konstruktionen billigare att tillverka. Genom en förstudie gällande den nuvarande designen och tillverkningsmetoden skapades en djupare förståelse av funktion och bearbetning. Projektet har följt en strukturerad produktutvecklingsprocess, från förstudie genom kravspecifikation, koncept -generering och -utvärdering till detaljkonstruktion. En kravspecifikation togs fram med hjälp av resultatet från förstudien tillsammans med information från anställda på Valmet. Två konceptgenereringssessioner genomfördes, 6-3-5 metoden och morfologisk matris, dessa gjordes tillsammans med personer på Valmet med olika erfarenheter. För konceptutvärdering och val användes Harris profile samt relativ beslutsmatris, dessa genomfördes efter konsultation med erfarna på Valmet. Det bästa konceptet är en konstruktionsändring som eliminerar de frästa vinklade väggarna i kilspåret på armen. Dessa ersätts av en cylindrisk ficka samt ett gängat hål. Motsvarande ändring görs på konsolen som armen ligger mot. Istället för de kilar som används idag föreslås två svarvade parter med konisk kontaktyta mellan varandra. Denna lösning uppnår alla krav i kravspecifikationen samt alla önskemål förutom att den ska passa liknande förband i andra delar av maskinen. Förklaringen till det är att de andra förbanden har något annorlunda funktion som den föreslagna lösningen inte tar hänsyn till. Prisskillnaden mellan den nuvarande och den av projektet föreslagna designen har tagits fram genom att en underleverantör lämnat prisförslag på båda.

Hip disarticulations and hemipelvectomies are the highest level of lower limb amputations. As such, these amputations create ambulation difficulties and current prosthetic solutions are limited. Powered prosthetic joints have successfully improved lower limb amputee gait; however, no powered hip joints are available on the market. This thesis presents the design and evaluation of a microprocessor-controlled powered hip joint for hip-level amputees. A rope and pulley system was used to transmit power from an actuator located at the prosthetic thigh to rotate the prosthetic leg around an anteriorly-located prosthetic hip joint. The pulley system features an innovative tensioning system using multiple keyways, allowing the system to be tensioned without external tensioning devices. The powered hip prosthesis passed ISO 15032:2000 mechanical strength tests that simulated 100 kg user loads. The joint was also tested by able-bodied individuals using a hip disarticulation simulator to walk with the powered hip-knee-ankle-foot prosthesis. Though the participants had asymmetrical gait with shorter intact-side swing time, the device successfully allowed the participants to ambulate. The final device weighed 3.9 kg and respected geometric design constraints to fit comfortably under pants. Future work is needed to implement a gait control system, resolve a rope slack issue, and test the device with hip-level amputees.

<p> A user-oriented computer program for an optimum solution of the hydrodynamic journal bearings is developed. The computer package is formulated in such a way to determine the optimum solution using only any of the following optimization techniques adapted from OPTISEP: DAVID, SIMPLEX, SEEK1, AND SEEK3. </p> <p> A user guide and a complete documentations for the computer package are included in the thesis. </p> / Thesis / Master of Engineering (ME)

This dissertation presents a comprehensive exploration encompassing the design, development, control and the application of reinforcement learning-based force planning for the autonomous grasping capabilities of the innovative assistive robotic exoskeleton gloves. Exoskeleton devices have emerged as a promising avenue for providing assistance to individuals with hand disabilities, especially those who may not achieve full recovery through surgical interventions. Nevertheless, prevailing exoskeleton glove systems encounter a multitude of challenges spanning design, control, and human-machine interaction. These challenges have given rise to limitations, such as unwieldy bulkiness, an absence of precise force control algorithms, limited portability, and an imbalance between lightweight construction and the essential functionalities required for everyday activities. To address these challenges, this research undertakes a comprehensive exploration of various dimensions within the exoskeleton glove system domain. This includes the intricate design of the finger linkage mechanism, meticulous kinematic analysis, strategic kinematic synthesis, nuanced dynamic modeling, thorough simulation, and adaptive control. The development of two distinct types of series elastic actuators, coupled with the creation of two diverse exoskeleton glove designs based on differing mechanisms, constitutes a pivotal aspect of this study. For the exoskeleton glove integrated with series elastic actuators, a sophisticated dynamic model is meticulously crafted. This endeavor involves the formulation of a mathematical framework to address backlash and the subsequent mitigation of friction forces. The pursuit of accurate force control culminates in the proposition of a data-driven model-free force predictive control policy, compared with a dynamic model-based force control methodology. Notably, the efficacy of the system is validated through meticulous clinical experiments. Meanwhile, the low-profile exoskeleton glove design with a novel mechanism engages in a further reduction of size and weight. This is achieved through the integration of a rigid coupling hybrid mechanism, yielding pronounced advancements in wearability and comfortability. A deep reinforcement learning approach is adopted for the real-time force planning control policies. A simulation environment is built to train the reinforcement learning agent. In summary, this research endeavors to surmount the constraints imposed by existing exoskeleton glove systems. By virtue of advancing mechanism design, innovating control strategies, enriching perception capabilities, and enhancing wearability, the ultimate goal is to augment the functionality and efficacy of these devices within the realm of assistive applications. / Doctor of Philosophy / This dissertation presents a comprehensive exploration encompassing the design, development, control and the application of reinforcement learning-based force planning for the autonomous grasping capabilities of the innovative assistive robotic exoskeleton gloves. Exoskeleton devices hold significant promise as valuable aids for patients with hand disabilities who may not achieve full recuperation through surgical interventions. However, the present iteration of exoskeleton glove systems encounters notable limitations in terms of design, control mechanisms, and human-machine interaction. Specifically, prevailing systems often suffer from bulkiness, lack of portability, and an inadequate equilibrium between lightweight construction and the essential functionalities imperative for daily tasks. To address these challenges, this research undertakes a comprehensive exploration of diverse facets within the exoskeleton glove system domain. This encompasses a detailed focus on mechanical design, control strategies, and human-machine interaction. To address wearability and comfort, two distinct exoskeleton glove variations are devised, each rooted in different mechanisms. An innovative data-driven model-free force predictive control policy is posited to enable accurate force regulation. Rigorous clinical experiments are conducted to meticulously validate the efficacy of the system. Furthermore, a novel mechanism is seamlessly integrated into the design of a new low-profile exoskeleton glove, thereby augmenting wearability and comfort by minimizing size and weight. A deep reinforcement learning based control agent, which is trained within a simulation environment, is devised to facilitate real-time autonomous force planning. In summary, the overarching objective of this research lies in rectifying the limitations inherent in existing exoskeleton glove systems. By spearheading advancements in mechanical design, control methodologies, perception capabilities, and wearability, the ultimate aim is to substantially enhance the functionality and overall efficacy of these devices within the sphere of assistive applications.

As the climate crisis draws more concern, research and development in wave energy as a renewable energy source has increased. Devices such as wave energy converters (WECs) are being researched, tested, and implemented to make wave energy a competitive power source. Testing of these devices is limited due to environmental concerns such as weather, location, and other issues. WECs require testing in a marine environment, however, performing testing in the actual environment may be difficult due to weather, access, mounting, and other issues. To eliminate environmental unknowns from testing, a wave simulator device can mimic wave behavior without the need for ocean or river testing. After doing research on wave energy and existing solutions, a wave generator device was conceptualized, designed, and manufactured to be used in Cal Poly’s Fluids Lab. The manufacturing portion was limited by time and funding to a small-scale model of the design which was tested and evaluated as the full-scale model would be. The design concept is a device that moves vertically on the back wall of a tank filled with water where the up and down motion will cause waves to form. The vertical motion is achieved by the device being pushed down and pulled up with a crank slider driven by a motor. The rotational motion produced by the motor is translated to linear motion by the crank slider mechanism. The device is restricted to the vertical motion with linear guide rails and attached to the tank with a structural frame. The scale model replicates this design and its components on a small-scale and is used as a proof-of-concept prototype. Its purpose is to validate the design concept and objective of simulating ocean waves. The validated design concept, proven by the scale design, will be manufactured at full-scale by future Senior Design Project teams at Cal Poly. The wave simulator device will be utilized by Cal Poly students, faculty, or affiliates to test different types of WECs.

No description available.

Fish farming or Aquaculture is a growing food-producing industry to culture the fish in artificially constructed tanks. A large number of fishes are reared in tanks for 100-150 days and produce food for the population. With increasing population and declining worldwide capture fishery, Aquaculture is perceived as a potential technique to meet the ever-expanding food demand without tarnishing the aquatic food chain. However, problems which are addressed in current systems like human intervention and unused feed material inhibit the production rate. This thesis provides methods and guidelines to resolve the challenges and simplify the mechanical design aspects of storage, transportation, and control of the dispensing process, which ultimately benefits the small-scale producers and entrepreneurs. Storing and distributing the fish feed along the fluid stream involves in considering multi-disciplinary engineering calculations. The fundamental knowledge of fluid mechanics, discrete element properties and mechanical design have been found to be an effective solution for such challenges. The results of this work provide information on designing the fish feeding mechanism incorporating fluid stream particle dispensing and evaluation of components present in the system. The thesis work provides solutions that serve as a starting point for low-cost design, validation and automation of components in a feeding mechanism for aquaculture industries. / Fiskodling eller vattenbruk är en växande livsmedelsproducerande industri för att odla fisk i konstgjorda tankar. Ett stort antal fiskar uppföds i tankar i 100-150 dagar och producerar mat för befolkningen. Med ökande befolkning och minskande världsfångstfiske uppfattas vattenbruk som en potentiell teknik för att möta den ständigt växande efterfrågan på livsmedel utan att skada vattenlevande livsmedelskedjan. Emellertid hämmar problem som tas upp i nuvarande system som mänsklig intervention och oanvänt foderråvara produktions hastigheten. Denna avhandling ger metoder och riktlinjer för att lösa utmaningarna och förenkla de mekaniska designaspekterna av lagring, transport och kontroll av utmatning processen, vilket i slutändan gynnar småskaliga producenter och entreprenörer. Lagring och distribution av fiskfoder längs vätskeflödet innebär att man överväger tvärvetenskapliga tekniska beräkningar. Den grundläggande kunskapen om fluidmekanik, diskreta element egenskaper och mekanisk design har visat sig vara en effektiv lösning för sådana utmaningar. Resultaten av detta arbete ger information om utformningen av fiskmatning mekanismen som innehåller vätskeflöde partikeldosering och utvärdering av komponenter som finns i systemet. Examensarbetet tillhandahåller lösningar som fungerar som utgångspunkt för lågkostnads konstruktion, validering och automatisering av komponenter i en utfodringsmekanism för vattenbruksindustrin.

Master of Engineering (ME)

Ballistic shields are used by defense teams in dangerous situations as protection against threats such as gunfire. When a ballistic shield is struck, the shield material will deform to absorb the kinetic energy of the incoming projectile. The rapid back-face deformation of the shield can contact the arm, which can impart a large force over an extremely short duration. This work modified an Anthropomorphic Test Device (ATD) to be used for the characterization of behind ballistic shield blunt impact loading profiles. The modified ATD was instrumented to measure impacts at the hand, wrist, forearm, and elbow to compare the force transfer at different locations of impact. A custom jig was designed to support the ATD behind a ballistic shield, provide a high degree of adjustability, and be subjected to impact testing. Two ballistic shield models, both with the same protection rating, were tested and showed to have statistically different responses to the same impact conditions, indicating further need for shield safety evaluation. To apply these loading profiles to future injury criteria development tests, a pneumatic impacting apparatus was re-designed that will allow the high energy impact profiles to be re-created in the McMaster Injury Biomechanics lab. Understanding the ballistic impact conditions, as well as the response of different ballistic shield models provided insight into the possible methods available to reduce upper extremity injury risk. This work has provided essential data for informing a future standard for shield safety evaluation. / Thesis / Master of Applied Science (MASc) / When a ballistic shield is impacted by a bullet it deforms to absorb the incoming energy. The high-speed deformation of the shield material can impact the arm leading to fracture and possible life-threatening risks if the shield is dropped due to this injury. At the time of this work, there were no standards that limited the amount of allowable back-face deflection or tools available that could measure the force transferred to the arm in this scenario. The purpose of this work was to develop a measurement device that could measure the force transferred to the arm from the behind shield impact. An existing crash test dummy arm was modified to provide measurement capabilities for this loading scenario. Ballistic shield testing was conducted where two different ballistic shield models were impacted to observe how the impact force changed with shield design, as well as the distance the device was placed behind the shield. A pneumatic impacting apparatus was then re-designed in the McMaster Injury Biomechanics lab that will allow the ballistic impact conditions to be re-created for evaluating the injury tolerance of the arm. The results of this work will be used to inform the future development of a ballistic shield evaluation standard.

The focus of this study is on the development of a state-of-the-art single-wheel roller rig for studying contact mechanics and dynamics in railroad applications. The use of indoor-based simulation tools has become a mainstay in vehicle testing for the automotive and railroad industries. In contrast to field-testing, roller rigs offer a controlled laboratory environment that can provide a successful path for obtaining data on the mechanics and dynamics of railway systems for a variety of operating conditions. The idea to develop a laboratory test rig started from the observation that there is a need for better-developed testing fixtures capable of accurately explaining the complex physics of wheel-rail contact toward designing faster, safer, and more efficient railway systems. A review of current roller rigs indicated that many desired functional requirements for studying contact mechanics currently are not available. Thus, the Virginia Tech Railway Technologies Laboratory (RTL) has embarked on a mission to develop a state-of-the-art testing facility that will allow experimental testing of contact mechanics in a dynamic, controlled, and consistent manner. VT roller rig will allow for closely replicating the boundary conditions of railroad wheel-rail contact via actively controlling all the wheel-rail interface degrees of freedom: cant angle, angle of attack, and lateral displacement. Two sophisticated independent drivelines are configured to precisely control the rotational speed of the wheels, and therefore their relative slip or creepage. A novel force measurement system, suitable for steel on steel contact, is configured to precisely measure the contact forces and moments at the contact patch. The control architecture is developed based on the SynqNet data acquisition system offered by Kollmorgen, the motors supplier. SynqNet provides a unified communication protocol between actuators, drives, and data acquisition system, hence eliminating data conversion among them. Various design analysis indicates that the rig successfully meets the set requirements: additional accuracy in measurements, and better control on the design of experiments. The test results show that the rig is capable of conducting various contact mechanics studies aimed for advancing the existing art. Beyond developing the experimental testing fixture for studying contact mechanics, this study provides a comprehensive review of the contact models. It discusses the simplifying assumptions for developing the models, compares the models functionality, and highlights the open areas that require further experimental and theoretical research. In addition, a multi-body dynamic model of the entire rig, using software package SIMPACK, is developed for conducting modal analysis of the rig and evaluating the performance of the rig's components. A MATLAB routine is also developed that provides a benchmark for developing creep curves from measurements of the rig and comparing them with existing creep curves. / Ph. D.