Pallet durability is a key characteristic with significant impact on a company's supply chain. Physical durability is defined as the number of trips that the pallet will accomplish before requiring repairs. Numerous studies have focused on understanding how durability is affected by different pallet components and warehouse environment characteristics. The VPI FasTrack is a testing sequence created to predict the performance of a pallet in a warehouse environment through different handling modes. However, this simulation has not been updated since its creation in 1993; therefore, a revision is needed to make it more closely reflect the behavior of a pallet in terms of durability. The objective of the current research was to investigate the ability of the FasTrack procedure to replicate the damages caused by material handling and storage systems in modern warehouses. This investigation was conducted through visual inspections of the damages seen on pallets used in the field, and pallets tested with FasTrack. The results of this study show the differences between the simulation-tested pallets and those from the field. The FasTrack simulation focuses heavily on top lead deckboard and stringer damage. The occurrence of damage modes such as splits and missing wood, were identified for these components. It was found that most of the damages from this simulation are created due to forklift handling. Because of substantial forklift handling damages, an experimental design was developed to investigate the effects of entry speed, payload, forklift type, and pallet design on the stresses exerted on a pallet, measured in terms of peak acceleration. The factors with the greatest effect on forklift peak acceleration and pallet peak acceleration were identified. The research shows that the acceleration in the pallet is approximately 4.4 times greater than the acceleration recorded in the forklift; however, the model of pallet acceleration based on forklift acceleration as a predictor shows poor performance. Different modifications to FasTrack are proposed according to the findings of this research. It is advised that they continue the FasTrack procedure past the point of repairable damage in a pallet, which is the usual practice when pallets are handled in the field. Further investigation of steps such as the flow rack and the stack storage are proposed, due to their low damage output during the simulation. The experimental design also showed that different damage severity levels from the FasTrack simulation are possible with variations in top load and entry speed. These changes could improve the ability of the VPI FasTrack to replicate the damages that pallets experience in the field. / Master of Science / Pallet durability refers to the number of uses that can be expected from a pallet before it needs to be repaired. Durability is an important performance characteristic, with a direct effect on the supply chain for any company. By further understanding how the warehouse environment and material handling systems affect pallet durability, companies can significantly reduce costs and improve their supply chain operations. The FasTrack procedure was created to satisfy the need for an effective durability simulation procedure. Created in 1993, FasTrack features different handling modes and interactions with handling equipment to reproduce the damages that a pallet could suffer in a real warehouse environment. However, warehouse environments have changed since the creation of FasTrack, which makes it important to assess the performance of this procedure in predicting pallet durability. The goal of this research was to investigate the ability of the FasTrack procedure to replicate the damages caused by material handling and storage systems in modern warehouses. This study was conducted through visual inspection of damaged locations, damage types, and damage severity levels for pallets used in the field and for pallets tested with FasTrack. The results obtained show differences between FasTrack and the field. The damage distribution in FasTrack for components of the pallet such as stringers and top lead deckboard is significantly higher than that measured in the field. The interaction of the pallet with the forklift could explain common damage modes, such as splits and missing wood, which were identified as the most damaged components in the pallets. An experimental design was developed to investigate the effects of entry speed, top load, forklift type, and pallet design on the stresses produced during interactions between forklifts and pallets. This interaction was measured in terms of horizontal shock impact acceleration. The most influential factors for forklift and pallet peak accelerations were identified with this study. An opportunity to predict pallet acceleration with forklift acceleration was identified, which could allow further investigation of the FasTrack simulation compared to the field. The results of the investigation show that FasTrack does not accurately reproduce the damages that pallets experience in the field. To improve the performance of the VPI FasTrack, the research proposes a revision of the steps during which damage output is low, such as the flow rack and the stack storage. The experimental design identified forklift entry speed and top load on the pallet as potential variables that could be customized in FasTrack, reflecting different severity levels based on a customer's unique environment characteristics. These changes could improve the correlation of the damages seen from the FasTrack simulation and the field, which would grant the industry a more reliable prediction of pallet durability.

Wireless technologies and networks are a part of our daily lives and we are surrounded by a constant stream of wireless signals. Unfortunately, there are a lot of limitations. At Toyota Material Handling Europe, future demands and expectations are raising but the technologies available today are not adapting fast enough. Indoor factory environments, moving network nodes and rapidly changing topologies are demanding situations. In this new Internet of Things day and age, transferring information in these challenging environments, the standard master and slave configuration is not enough. This report looks at the specific challenges establishing a wireless communication link between trucks in an indoor factory and warehouse environment. There are many factors to consider. Antennas, noise, frequency bands, different network technologies, propagation and path loss modeling to mention a few. Antennas and on-the-truck antenna positioning require design choices to be made. If we want to benefit from using high gain antennas, positioning is an important factor. Noise, in the highly congested 2.4 GHz band is a problem, especially considering safety critical applications. The license free ISM frequency bands have all different advantages in range, available communication protocols and amount of other technologies sharing the spectrum. The Wi-Fi, Bluetooth, ZigBee and V2X technologies looked at, tailored to the particular case of a warehouse environment like the Toyota factory, and the final selection relates to potential use case scenarios. Prioritizing, scalability, ad hoc network topologies, low latencies and short connection times together with long range, the new V2X technology building upon the IEEE 802.11p standard stands out. This report evaluates the IEEE 802.11p wireless standard running the ETSI ITS G5 V2X protocol in an indoor factory and warehouse environment. Thanks to Kapsch and their EVK-3300 V2X Evaluation Kit it was possible to evaluate transferring information between nodes, the PSR, and looking at how useful different path loss models are for estimating relative distances between trucks.

Reach truck masts are subjected to oscillations, which have significant impacts on the dynamics of the entire vehicle. Mast oscillations can cause undesirable outcomes in extreme situations and therefore it is desirable to be able to predict these outcomes before they occur. A forklift manufacturer in Mjölby initiated a thesis with the intention to obtain a model that can simulate mast sway for situations where oscillations occur. The objective of the thesis was to create a model of Triplex masts and find dependencies between model parameters and variables such as fork height and load. The thesis was conducted modelling the mast with a rigid multibody approach where torsion springs and dampers were used between mast parts to simulate mast elasticity. Clearance at the connections were considered and included in the model. The obtained model constitutes of 8 parameters that could be tuned to attain different oscillation characteristics. Parametric optimisation was carried out to find optimal sets of parameters for compliance with sway measurement tests with different load and fork height cases.  The thesis has resulted in a model that is able to simulate mast sway with different oscillation characteristics depending on model parameters. Performed parametric optimisation resulted in parameters that reveal useful information about how model parameters depend on load and fork height. The method used for obtaining optimal parameters can likewise be applied to other mast models in order to gain insight into model parameters as functions of load and fork height.

<p>This is a final thesis done at BT, considering one of their forklift truck models called Reflex. The first part of this report is about a preliminary investigation investigating what kind of diagnostic systems BTwants to use, and also which demands there are to meet all expectations on such system. Secondly a diagnostic system, which will show if the drive wheel is worn out, will be presented. </p><p>In the preliminary investigation, two kinds of diagnostic systems were mentioned. These were Model based diagnosis and Predictive analysis. Model based diagnosis is based on measurements made by sensors at the truck, while predictive analysis is based more on statistics and retrieved data about the lifetime of a truck in specific environments. </p><p>The diagnosis system for the drive wheel is based on a model made in Matlab's Simulink. Due to poor documentation, rough simplifications in the model have been made. However, one can still see the differences of principle. </p><p>The main thought was detecting a difference in the lowest torque level from the engine, varying the diameter of the drive wheel. By measurements made directly at the truck, different torques could be observed with varying diameter of the drive wheel, varying load on the truck and varying friction in the gearbox. Using hypothesis tests, it is possible to say whether the drive wheel is worn out or not. </p><p>Results show that if the drive wheel diameter is reduced by 25 mm, torque is reduced by 7% and if the drive wheel diameter is reduced as much as 50 mm, a torque reduction of 11% would be achieved.</p>

This master thesisinvestigates the possibilities to implement a digital filter for wire guidancein a truck. The analog circuits in the truck, today, are analyzed to understandtheir signal processing. The component MAX261 is especially interesting and itis analyzed in a special Section to make sure that all needed details, todevelop a digital filter, are available. When all theoretical calculation wasfinished, all the circuits were simulated to make sure that the calculationsare correct.   The digital filter is based onan analog filter which is expensive and not so easy to purchase. A requirementspecification was developed by analysis of the properties of the analog filterand how it is currently used. The analog filter is a part of a chain of analogsignal processing which mostly can be performed digitally instead.   The special type of the analogfilter makes the requirements, on the digital filter, very tough and anextensive analysis of digital filter structures was performed in order to finda suitable filter. The digital filter is of WDF (Wave Digital Filter)-type andit is very special, because it has two variable coefficients, one for thesteepness and one for the center frequency. The digital filter consists of anumber of first order filters, because a higher order filter with desiredproperties has coefficient values that are large which makes the stabilityproperties worse.   The best type ofimplementation of this filter and the signal processing are also analyzed.Finally, a prototype was developed on a development board where the maincomponent is a DSP (Digital Signal Processor). The program for the prototype iswritten in C-code and the performance of the system was verified by differenttests and measurements.

This is a final thesis done at BT, considering one of their forklift truck models called Reflex. The first part of this report is about a preliminary investigation investigating what kind of diagnostic systems BTwants to use, and also which demands there are to meet all expectations on such system. Secondly a diagnostic system, which will show if the drive wheel is worn out, will be presented. In the preliminary investigation, two kinds of diagnostic systems were mentioned. These were Model based diagnosis and Predictive analysis. Model based diagnosis is based on measurements made by sensors at the truck, while predictive analysis is based more on statistics and retrieved data about the lifetime of a truck in specific environments. The diagnosis system for the drive wheel is based on a model made in Matlab's Simulink. Due to poor documentation, rough simplifications in the model have been made. However, one can still see the differences of principle. The main thought was detecting a difference in the lowest torque level from the engine, varying the diameter of the drive wheel. By measurements made directly at the truck, different torques could be observed with varying diameter of the drive wheel, varying load on the truck and varying friction in the gearbox. Using hypothesis tests, it is possible to say whether the drive wheel is worn out or not. Results show that if the drive wheel diameter is reduced by 25 mm, torque is reduced by 7% and if the drive wheel diameter is reduced as much as 50 mm, a torque reduction of 11% would be achieved.

The currently low requirements on sound emissions for industrial trucks are expected to be raised in the near future. The company Kalmar Industries AB, which develop, produce and market industrial trucks, want to improve their truck silencers as a precaution to the future harder restrictions and also to improve their competitiveness. The sound emission produced by a vehicle depends on type and range of application it is designed for but the dominant part of the sound is usually produced by the engine and silencer. A new measuring method is developed for studying sound emanating through the silencer system. The analysis of the measurement data establishes that the silencers are not working well. The simulations made with SIDLAB, which is a computer programme for calculating the propagation of sound in ducts, confirms that the silencers are inefficient and that they are simply too small. A simulation which implements a parallel resonator in the main silencer shows that it is possible to make great improvements in reducing the noise from the truck as well as meeting requirements on space. Mathematical modelling based on linearity and one-dimensional interaction between the silencer elementsis advantageous and gives very good results when understanding, analysing and simulating the silencer. The simulation tool SIDLAB works well and saves a lot of time by its fast modelling and easy interface.

<p>The currently low requirements on sound emissions for industrial trucks are expected to be raised in the near future. The company Kalmar Industries AB, which develop, produce and market industrial trucks, want to improve their truck silencers as a precaution to the future harder restrictions and also to improve their competitiveness. The sound emission produced by a vehicle depends on type and range of application it is designed for but the dominant part of the sound is usually produced by the engine and silencer.</p><p>A new measuring method is developed for studying sound emanating through the silencer system. The analysis of the measurement data establishes that the silencers are not working well. The simulations made with SIDLAB, which is a computer programme for calculating the propagation of sound in ducts, confirms that the silencers are inefficient and that they are simply too small.</p><p>A simulation which implements a parallel resonator in the main silencer shows that it is possible to make great improvements in reducing the noise from the truck as well as meeting requirements on space.</p><p>Mathematical modelling based on linearity and one-dimensional interaction between the silencer elementsis advantageous and gives very good results when understanding, analysing and simulating the silencer. The simulation tool SIDLAB works well and saves a lot of time by its fast modelling and easy interface.</p>

Standup forklift trucks are extensively used primarily for material handling in high density warehouses. These forklifts over the years have been involved in severe accidents causing injuries and taking lives of the operator and that of people on the floor. The major accidents involving these trucks are tip-over, off the dock accidents, compartment intrusions and under the rack injuries. The objective of the work is to analyze the accident data and to provide a conceptual design to ensure safety of the operator riding the standup forklift trucks. The operator is assumed to be safe when retained within the compartment similar to that of the safe space environment of a sit down forklift truck or tractors. Thus a door on the standup forklift would provide a safer compartment. This design would help in preventing severe injuries to the operator in case of any accidents. The important criterion of this design is to provide a door with latch and slide mechanism to ensure easy egress and ingress of the operator. The compartment is designed ergonomically for 95th percentile industrial male population. The accident data is studied by performing statistical and failure analysis. Weibull plots are fitted for life time distribution data and are found to be of increasing rate. This suggests that present safety precautions are increasingly ineffective.

Today’s demand on forklift trucks performance and efficiency is high. The productivity is important but also the experience while handling the forklift. The handling has to be simple and genuine to make the driver feel confident and safe. To achieve high performance steering in articulated trucks, a hydraulic power system is often used.Simulation software are a powerful tool in development processes. The program gives the industry a possibility to develop, analyze and evaluate constructions and models more efficient.The purpose of this master thesis is to identify and increase the knowledge about the main challenges in the hydraulic steering system in an articulated forklift. The hydraulic system has been modelled in the simulation software Hopsan and validated against data from measurements performed on the forklift. The different challenges have been identified based on tests and the simulation results. For a deeper understanding of the system a literature study, mainly about the key components, has been done during the master thesis. A number of suggestions for improvement have been developed with focus on increasing the steering performance. The concepts and ideas have been evaluated and tested in the simulation model.The project resulted in a validated simulation model of the articulation and a number of suggested improvements on the hydraulic steering system.