The purpose has been to analyze a modelling process based on the finite element method (FEM), for a powered stacker truck of the model SPE 140 TX HILO. It was analyzed how such a model should be designed in order to perform stability analyses. This was done by analyzing which of the trucks components that were relevant from a stability perspective. These components were analyzed in order to figure out which modelling approach that was best suited to model the components in a FEM-software. The result of these analyses is a modelling methodology describing which approach that should be used during the entire modelling process of a FEM-model consisting of an entire truck.

Material handling and logistics are fundamental parts of today’s global societyand forklifts are a crucial part of the material handling process. Making these asefficient and reliable as possible are therefore of great interest. In this master thesis, an effort has been made to improve the control of the hydraulic lowering function of a specific forklift. Today the lowering function iscontrolled through an open-loop control scheme making the control performancesensitive to disturbances and system changes. One disturbance of special interestis the temperature of the hydraulic fluid. The goal of this thesis was therefore todesign a controller with improved robustness as well as improved performance. To solve this a model-based control design approach was used and a nonlineargrey-box model was derived, implemented and validated. The model parameterswere estimated using a nonlinear least-squares optimisation problem. The resulting model captures most of the system dynamics and the model fit is higher than 70% which was deemed good enough to use for control design. A PID controller was designed based on the estimated model and the controllerparameters were optimised. Furthermore, the controller was evaluated in simulations and implemented in a real forklift. The proposed controller was compared to the original controller for various scenarios. The results reveal improvedsteady state behaviour with enhanced temperature robustness compared to theoriginal controller. / Materialhantering och logistik är viktigt för att dagens globala samhälle ska fungera. En grundläggande del i materialhanteringsprocessen är gaffeltruckar, därför är det av intresse att göra gaffeltruckar så effektiva och pålitliga som möjligt. I det här examensarbetet har ett försök gjorts till att förbättra styrningen av den hydrauliska sänkningsfunktionen hos en specifik gaffeltruck. Dagens lösning använder sig av öppen styrning vilket gör reglerprestandan känslig för störningar och systemförändringar. En störning av extra intresse är temperaturen av hydraulvätskan. Målet med detta arbete var därför att designa en regulator med ökad robusthet och prestanda. För att lösa detta har en modellbaserad metod för regulatordesign använts där en olinjär gray-box modell härleddes, implementerades och validerades. Modellparametrarna skattades genom att ställa upp och lösa ett ickelinjärt minsta-kvadrat optimeringsproblem. Den resulterande modellen fångar det mesta av systemdynamiken och modellpassningen till uppmätt data var högre än 70\% vilket ansågs bra nog för att kunna använda modellen som en bas för regulatordesign. En PID regulator designades och regulatorparametrarna optimerades med hjälp av modellen. Regulatorn utvärderades i simuleringar och för att sedan implementeras den på en riktig gaffeltruck. Den föreslagna regulatorn jämfördes med den ursprungliga regulatorn i flera olika testfall. Resultaten visade ett bättre steady-state beteende och ökad robusthet mot temperaturförändringar för den designade regulatorn jämfört med den ursprungliga regulatorn.

Not many people think of design when they hear the word forklift. It is a vehicle associated with labor, a machine that has the purpose of making work more efficient and profitable. Though that is true, for a company producing forklifts can the design be a very important factor for a lucrative business. A forklift that can express high functionality is more capable to compete on the market. This thesis describes the product development of a forklift for the company Semax. The work is a design project and focuses on the visual expression of the product. The goal was to improve the exterior to be more cohesive and more aesthetically pleasing. The report covers certain methods that can be used during a design project of this nature. It will explain the process in the order it was conducted and describes research, findings, ideation and result.

This diploma thesis was created for company ICE industrial services which develops and manages PLC software for company Alcan Strojmetal Aluminium Forging, s.r.o.. The purpose of thesis is analyze software for control line of thermal processing of aluminium forgings, design and implement modifications in control software, check functions and finally wrote control of new modifications in manual.

No description available.

This thesis explored the possibility to use line following technology to automate forklifts in a warehouse scenario. This was done to reduce the need for staff to always be present in the warehouse. A prototype forklift was constructed with three wheels, where driving and steering was done by the rear wheel. To control the forklift an Arduino Uno was used. The line following was done using Infrared Radiation (IR) sensors. Different setups of line following sensors were tested to achieve a forklift capable of following a line. Different layouts of the operating area were also tested. Line following was found to work best when two sensors were placed in front of the front wheels when going forward and two by the back wheel when reversing. The conclusion was made that a setup of four sensors was enough to achieve a line following forklift. For the operating area, the best layout was found to be an X-shaped one. Using 90° corners proved to be the easiest to navigate. / Denna avhandling undersökte möjligheten att använda linjeföljningsteknologi för att automatisera gaffeltruckar i ett varuhus. Detta gjordes med målet att minska behovet på att alltid ha personal närvarande. En gaffeltrucksprototyp konstruerades med tre hjul, bakhjulsdrift och styrning på bakhjulet. För att styra gaffeltrucken användes en Arduino Uno. Linjeföljningen utfördes av IR sensorer. Tester utfördes på olika konfigurationer av linjeföljarsensorerna för att uppnå linjeföljning. Utformningen på arbetsområdet testades också. Linjeföljning visade sig fungera bäst när två sensorer var placerade framför framhjulen när man körde framåt och två vid bakhjulet när man backade. Slutsatsen blev att fyra sensorer var tillräckligt för att uppnå linjeföljningsförmåga. Den bästa utformningen på arbetsytan konstaterades vara en X-formad yta. Att använda 90° hörn visade sig vara lättast att navigera genom.

Companies are having to adhere to higher demands regarding their environmental emissions, this also stands true for the companies warehousing. In warehouses, both picking and moving goods is done using forklifts which leads to energy use and thereby environmental emissions for these activities. Two ways of reducing these emissions are to plan routes for the forklifts that minimize travel distance, or placing the goods such that it reduces the total travel distance. One company that offers IT solutions which make optimizations like this possible is Consafe Logistics. Situated in Lund, Sweden, Consafe Logistics serves over 250 customers worldwide. The company’s main product is Astro WMS, a Warehouse Managing System with different optional modules that, for example, can reduce forklift driving using the methods described above. In this study three of these modules are studied; Slotting, Goods Move Optimization, and Pick Route Optimization. Slotting and Pick Route Optimization aim to optimize picking of goods while Goods Move Optimization aims to optimize moving of goods. Consafe Logistics have knowledge regarding how the implementations of the modules reduce travel distance and travel time, but they do not know what environmental effects these reductions have. Because Consafe Logistics customers differ in their warehousing it also becomes relevant to study how the environmental effects of the modules vary depending on which customer that implements the modules. Therefore, the aim of this study is “To create a model for reduction of carbon dioxide equivalents (CO2e) in warehousing for different customer segments when using Astro WMS modules to optimize the warehouse.” To study how the environmental effects, differ depending on which customer is regarded, the customers needed to be separated. This was done by identifying the customers’ differing characteristics. For characteristics, physical aspects, conditions, circumstances, and/or strategic differences, was regarded. Determining the characteristics was done using seven interviews with customers. The interviewees all had responsibilities for managing and developing activities in the warehouse. The customers were interviewed regarding what parts of warehousing affect how much forklift driving that was needed in the warehouse. The customers then ranked the characteristics and an aggregated list of what customers regarded as most important. In parallel to a literature study about compartmentalizing customer warehouses, the list was presented to the commissioner who determined what characteristics to study. From the chosen characteristics, area of the warehouse, number of orders handled, and carbon dioxide intensity (gCO2e per generated kWh as customer segment). For each segment there was multiple subdivisions, for example the big area of the warehouse (>20 000 m2). Carbon dioxide intensity was used to highlight that some warehouses give rise to more or less environmental effect depending on how much carbon dioxide that is emitted when generating the used electricity. The customer segments and subdivisions were then used to categorize the customers into different segments for each studied module. The effect on potential kgCO2e savings from different segments was then studied together with the effects of the different modules. From the results, a correlation was observed between a bigger warehouse area and more orders, and potentially saved carbon dioxide equivalents. This was true independently of what module was being studied. The highest observed yearly reduction was 1620 kgCO2e when using Goods Move Optimization and electricity with high carbon dioxide intensity. / Allt högre krav ställs på företag att reducera sina miljömässiga utsläpp, och detta är bland annat möjligt inom lagerverksamheter. På lager sker både plock och flytt av gods med truckar, vilket leder till energiåtgång och därmed även en miljöpåverkan vid utförandet av dessa lageraktiviteter. Två sätt att reducera miljöpåverkan från truckarna är att planera rutter som minimerar körsträcka, eller att placera gods på ett sätt som reducerar den totala körsträckan. Ett företag som erbjuder IT-lösningar som möjliggör sådana effektiviseringar är Consafe Logistics. Consafe Logistics är situerat i Lund med över 250 kunder globalt. Företagets huvudprodukt är Astro WMS, ett Warehouse Management System med olika moduler som möjliga tillägg för att exempelvis effektivisera lagerverksamhet genom optimering av truckkörning enligt ovan. I denna studie undersöks tre moduler i Astro WMS; Slotting, Goods Move Optimization, och Pick Route Optimization. Slotting och Pick Route Optimization effektiviserar plockning och Goods Move Optimization effektiviserar förflyttning av gods. Consafe Logistics har insikt i vilken reducering som finns att göra från implementation av dessa moduler i mån av tidsåtgång och körsträcka, men inte vilken miljömässig besparing som finns att göra. Eftersom samtliga 250 kunder till Consafe Logistics är olika till sin lagerverksamhet är det även av intresse att undersöka hur kunders miljömässiga besparing kan variera baserat vilken kund som implementerar modul. Därmed är syftet med denna rapport ”Att ta fram en modell för besparade koldioxidekvivalenter inom lagerverksamheten hos olika kundsegment vid användandet av Astro WMS moduler för optimering av lager.” För att undersöka hur besparade koldioxidekvivalenter (CO2e) kan variera beroende på vilken kund som avses behövde först de olika kunderna differentieras från varandra. Detta genomfördes genom identifiering av kundernas olika karaktäristik. Med karaktäristik avsågs fysiska egenskaper, förutsättningar, och/eller strategiska val tillhörande en kunds lager. Framtagning av karaktäristik genomfördes via sju kundintervjuer. Gemensamt för intervjupersonerna var deras ansvar för utveckling eller styrning av logistikverksamheten. Kunder intervjuades gällande vilka delar av lagerverksamheten som påverkade hur mycket truck som behövde köras. Kunder rangordnade sedan dessa och en sammanvägd lista över karaktäristik framtogs. Parallellt med en litteratursökning i uppdelning av kunds lager presenterades detta till uppdragsgivare för fastställande av karaktäristiker att undersöka. Från den valda karaktäristiken framtogs lageryta, antalet order som hanterades, och koldioxidintensitet (gCO2e per genererad kWh som kundsegment). Varje kundsegment delades upp i flera intervall, exempelvis intervallet stor lageryta (>20 000 m2). Koldioxidintensitet användes för att understryka att lager erhåller mer eller mindre miljömässiga besparingar baserat på hur mycket kgCO2e som släpps ut vid framtagande av elenergi. Kundsegment och dess intervall avsåg kategorisera varje individuell kund till respektive kundsegment. Påverkan på potentiell besparing kgCO2e från olika segment och intervall studerades sedan för undersökta moduler. Från resultaten observerades en korrelation mellan ett högre värde på lageryta respektive antal orderrader och potentiell besparing kgCO2e. Detta var sant oberoende av vilken modul som studerades. Högst uppskattad besparing över samtliga undersökta kunder var 1620 kgCO2e årsvis vid användandet av Goods Move Optimization och elenergi med hög utsläppsintensitet.

No description available.

Industrial forklifts consist of one of the most common handling methods for pallets in warehouses and distribution centers. Pallets deflect while they are being transported by forklifts due to the weight of the unit load. Thus, most of the deflection is observed to occur on the outside edges and corners of the pallet. Several international standards are used in order to define the maximum deflection for pallet bending, including ISO 8611 and ASTM D1185. However, there is still a lack of understanding on the accuracy of these deflection limits and the exact performance of a pallet during a forklift support condition. Understanding pallet bending during forklift support condition and how it affects the stability of a unit load helps create an industry accepted deflection limit that will help to design safer and more cost-effective pallets. For this study, two chapters were proposed in order to assess pallet deflection and unit load stability. The first chapter consisted of measuring and analyzing the vibration levels for three different industrial forklifts affect by factors such as the speed, the payload of the unit load carried, sensor location, forklift type, and road conditions. The results obtained showed that the highest vibration intensity occurred at 3-4 Hz, while the highest overall Grms value observed was 0.145 G2/Hz (between 1-200 Hz). An increase in the forklift speed caused an increase in vibration intensity. In contrast, an increase in the unit load weight carried by the forklift caused a decrease in vibration intensity. Among the three forklifts studied, the gas-powered forklift had the highest vibration intensity, and all forklifts, when driven on asphalt, experienced more vibration. The second chapter of the research project consisted of evaluating pallet deflection under forklift handling conditions. These conditions included fork tines configuration (leveled and 4° angle), unit load condition (bound and unbound), pallet orientation (across width and across length), and type of handling condition (static and dynamic). The results showed that when unit loads were handled in a static condition, they survived the throughout the entire testing. However, when they were tested under a dynamic condition, and specifically, with the unbound unit loads, they did not survive the entire testing. Moreover, unit loads that were tested with the 4° angle forktines configuration tended to survive longer during the dynamic testing. For this particular case, the unit load capacity obtained based on the ISO 8611 standard was too conservative. / M.S. / Forklifts play an important role in the transportation of materials goods in the supply chain. Pallets experience vibration when they are handled by industrial forklifts. This vibration plus the combined effects mainly due to the unit load weight affects the amount that pallets bend. Thus, depending on the amount of pallet bending, they can produce unit load instability. Currently, there is a lack of understanding of how much pallet bending is acceptable. Therefore, the goal of this research was to understand the behavior of pallet bending when they are handled under forklift conditions. Two experiments were conducted in order to study pallet deflection under forklift handling conditions. The first experiment, which consisted in analyzing forklift vibration, showed that an increase in the forklift speed caused an increase in vibration intensity. In contrast, an increase in the payload of the unit load resulted in a decrease in vibration intensity. Among the three forklifts studied, the gas-powered forklift showed the highest vibration intensity. Forklifts driven on asphalt experienced more vibration in comparison to the ones driven on concrete. The second experiment, which consisted in assessing pallet deflection under a simulated forklift handling condition, showed that unit loads under a dynamic environment (vibration) increased the probability of unit load instability. Furthermore, it was observed that applying stretch wrap to a unit load decreased its instability and at the same time increases its survivability. Also, the results showed that the proposed ISO 8611 deflection limit is too conservative for this particular handling condition.

This thesis explains the model-based design of a fork control system in a turret head operated Very Narrow Aisle forklift in order to evaluate and push the limits of the current hardware architecture. The turret head movement consists of two separate motions, traversing and rotation, which both are hydraulically actuated. The plant is thoroughly modeled in the Mathworks softwares Simulink/Simscape to assist in the design of the control system. The control system is designed in Simulink/Stateflow and code-generated to be evaluated in the actual forklift. Optimal control theory is used to generate a minimum-jerk trajectory for auto-rotation, that is simultaneous traversing and rotation with the load kept in centre. The new control system is able to control the system within the positioning requirements of +/- 10 mm and +/- 9 mrad for traversing and rotation, respectively. It also shows good overall performance in terms of robustness since it has been tested and validated with different loads and on different versions of the forklift. However, the study also shows that the non-linearities of the system, especially in the hydraulic proportional valves, causes problems in a closed-loop control system. The work serves as a proof of concept for model-based development at the company since the development time of the new control system was significantly lower than for the original control system.