Browse Topic: Vehicle front ends
A passenger vehicle's front-end structure's structural integrity and crashworthiness are crucial to ensure compliance with various frontal impact safety standards (such as those set by Euro NCAP & IIHS). For a new front-end architecture, design targets must be defined at a component level for crush cans, longitudinal, bumper beam, subframe, suspension tower and backup structure. The traditional process of defining these targets involves multiple sensitivity studies in CAE. This paper explores the implementation of Physics-Informed Neural Networks (PINNs) in component-level target setting. PINNs integrate the governing equations into neural network training, enabling data-driven models to adhere to fundamental mechanical principles. The underlying physics in our model is based upon a force scheme of a full-frontal impact. A force scheme is a one-dimensional representation of the front-end structure components that simplifies a crash event's complex physics. It uses the dimensional and positional parameters of the components, along with their force-displacement curves, to estimate the vehicle's crash pulse. In this work, we have implemented PINNs to generate an optimized force scheme using the historical CAE test data. Using this approach promises to cut short the time and cost that goes into the conventional process of target setting.
In this article we will discuss the development and implementation of a computer vision system to be used in decision-making and control of an electro-hydraulic mechanism in order to guarantee correct functioning and efficiency during the logistics project. To achieve this, we have brought together a team of engineering students with knowledge in the area of Artificial Intelligence, Front End and mechanical, electrical and hydraulic devices. The project consists of installing a system on a forklift that moves packaged household appliances that can identify and differentiate the different types of products moved in factories and distribution centers. Therefore, the objective will be to process this identification and control an electro-hydraulic pressure control valve (normally controlled in PWM) so that it releases only the hydraulic pressure configured for each type of packaging/product, and thus correctly squeezing (compressing) the specific volume, without damaging it due to excessive force, and without little force to the point of allowing the load to fall.
The proliferation of the electric vehicle (EVs) in the US market led to an increase in the average vehicle weight due to the assembly of the larger high-voltage (HV) batteries. To comply with this weight increase and to meet stringent US regulations and Consumer Ratings requirements, Vehicle front-end rigidity (stiffness) has increased substantially. This increased stiffness in the larger vehicles (Large EV pickups/SUVs) may have a significant impact during collision with smaller vehicles. To address this issue, it is necessary to consider adopting a vehicle compatibility test like Euro NCAP MPDB (European New Car Assessment Program Moving Progressive Deformable Barrier) for the North American market as well. This study examines the influence of mass across vehicle classes and compares the structural variations for each impact class. The Euro NCAP MPDB (European New Car Assessment Program Moving Progressive Deformable Barrier) protocol referenced for this analysis. Our evaluation approach comprises of two sections: (i) The impact of the barrier mass on to the vehicle structure (V2B) and (ii) vehicle-to-vehicle impact (V2V) analysis. To predict the correct segment weight representing the barrier weight for the North American market, we analyzed the 2022 year to sales data for North American market to assess the average vehicle weight. Data was then compared with CAE predictions barrier mass (~1500kg- 1600kg). Based on the sales data, the average vehicle mass found to be ~1500 kg, aligning with the CAE simulations predictions. This study aims to determine the US sales volume and conduct CAE simulations to predict the precise weight of the barrier that replicates the lightest vehicle currently available in the North American market, as per this study, a barrier weight of (~1500 -1600) kg can be considered for the future vehicle compatibility for NA market. This predicted vehicle weight aligns with the typical vehicle sale data for North American market. Background In 2022, Electric Vehicles (EVs) constituted 14% of all car sales globally, with every major market experiencing year-over-year sales increase. In United States, this meant that over one in five cars sold were electric. To improve the range of EVs, Original Equipment Manufacturers (OEMs) are significantly increasing the weight of high-voltage battery assemblies, leading to an overall increase in the vehicle weight, this in turn, results in substantial increase in front-end-stiffness of the vehicle to meet other US vehicle regulations. The heightened front-end-stiffness is expected to significantly impact vehicle compatibility. To understand various parameters such as Occupant Loading Criterion (OLC) and Standard Deviation (deformation of barrier profile), we referenced Euro NCAP MPDB (European New Car Assessment Program Moving Progressive Deformable Barrier) test protocol. This helped determine the weight of the barrier that represents the small vehicle segment in the North American market. Vehicle-to-Vehicle (V2V) impact CAE simulations were also conducted, selecting smaller vehicle as target vehicles (to represent the barrier mass), and impacting them with different vehicle classes such as Pick-up trucks, Large SUVs, and Compact SUVs. The impact vehicle mass varied from 1800kg to 3200kg.The primary aim of this study is to estimate the barrier weight that replicates the lightest vehicle currently available in the North American market.
Physical testing is required to assess multiple vehicles in different conditions, specially to validate those related to regulations. The acoustic evaluations have difficulties and limitations in physical test; cost and time represent important considerations every time. Additionally, the physical validation happens once a prototype has been built, this takes place in a later phase of the development. Sound pressure is measured to validate different requirements in a vehicle, horn sound is one of these and it is related to a regulation of united nations (ECE28). Currently the validation happens in physical test only and the results vary depending on the location of the horn inside the front end of every vehicle. [7] In this article, the work for approaching a virtual validation method through CAE is presented with the intention to get efficiency earlier in product development process.
In today’s scenario, internal combustion engines have conflicting requirements of high power density and best in class weight. High power density leads to higher loads on engine components and calls for a material addition to meet the durability targets. Lightweight design not only helps to improve fuel economy but also reduces the overall cost of the engine. Material change from cast iron to aluminium has a huge potential for weight reduction as aluminium has 62% lesser mass density. But this light-weighting impacts the stiffness of the parts as elastic modulus drops by around 50%. Hence, this calls for revisiting the design and usage of optimization tools for load-bearing members on the engine to arrive at optimized sections and ribbing profiles. This paper discusses the optimization approach for one of the engine components i.e., the FEAD (front end accessory drive) bracket. FEAD brackets are used to mount one or more auxiliary components and are subjected to vibrational loads due to engine base excitations and the typical mode of failure is vibrational fatigue failure. Hence the bracket ribbing direction, sections and dimensions need to be designed to meet the safe frequency target and desired life through the vibration fatigue duty cycle. Furthermore, the stresses should be within a safe target due to belt load and peak gravity loads. The objective of this paper is to redesign the existing cast iron bracket and redistribute the material through topology optimization with an alternate material. Aluminium was selected as desired material. The functional requirement is to maximize frequency to the targeted frequency and maximize the stiffness of the bracket. Frequency-based optimization to improve the modal frequency and weighted compliance-based optimization to improve the static stiffness of the bracket has been deployed. Optimization in concept design provided the appropriate ribbing based on load path and faster convergence to a workable solution. The optimized design has been verified and is meeting the acceptance criteria in strength and fatigue simulation. Furthermore, an actual part based on the concept design was developed and has been validated successfully in the critical durability cycle. A comparative vibration measurement was performed for both cast iron and aluminium bracket to understand the NVH capability of the aluminium concept bracket.
In the present work, it is investigated how a flush arrangement to the outer skin affects the aerodynamic characteristic curve of active grille shutters (AGS). For this purpose, a recently developed theory, which analytically describes the aerodynamic behavior of AGS arranged in a straight flow channel, is extended accordingly, and the influence of an arrangement of AGS flush with the outer skin is first theoretically analyzed. The theoretical results are then validated experimentally. For this purpose, measurements of real vehicles with suitable AGS are used. The results show a good agreement of the theoretical predictions with the experiment. The theoretical and experimental analyses allow conclusions to be drawn as to how and under what conditions an arrangement flush with the outer skin affects the aerodynamic behavior of AGS.
In autonomous driving system, lane change decision-making plays an important role as the front-end of lateral control. However, the current prediction methods of lane change are typically performed by using basic variables as the features of model without deep processing, which reduces the accuracy of the prediction. Therefore, we propose a binary logistic regression method to solve the lane change decision problem under expressway conditions, which treat quantified willingness and risk as the inputs. Firstly, we design Lane Changing Willingness function and Lane Changing Risk function with the minimum safety spacing theory and traffic environment factors. Secondly, a binary logistic regression method for predicting lane change behavior is proposed. Thirdly, we develop the driving simulation platform with low latency data collecting tools and design the experiments. After training the model with the experiment data, the proposed method predicts the lane change decision with 94.02% accuracy, and the time consumed for predicting 10, 000 samples is only 34 milliseconds.
During the development phase of any Powertrain component/subsystem for a conventional ICE or an XEV (Hybrid/Battery Electric Vehicle), system Energy efficiency and Performance improvement simulations are a very important step to prove the worthiness of the product before we can advance to building Prototypes, Vehicle level Integration, Testing, analysis and benefit’s evaluation phases. This work describes how two simulation tools have been leveraged effectively for Energy efficiency and Performance simulations for an Electric vehicle. Schaeffler has an internal Physical Modelling Tool (PMT) for building vehicle level models. This tool has readymade physical blocks for various Mechanical and Electrical components. These blocks can be parameterized as per required specifications. The powertrain subsystems like the Battery, BLDC Motor, Vehicle Dynamics and the Multi-speed transmission consisting of various mechanical elements have been modelled and parametrized using this tool. This tool is the front end of the Co-simulation. The Physical model is used to provide various model inputs like Drive cycles, Motor and Battery characteristics, Throttle and Gear Shift maps. On the backend we leverage the Equation and Logics modelling capabilities of Matlab Simulink. The Driver and the Vehicle models have been made using Matlab Simulink. The Driver model consists of logics which provides various outputs like Throttle, Brake and vehicle Power demand. The Vehicle models consists of algorithms which provides outputs like Desired Motor Torque and transmission gear position. These two Matlab Simulink models are converted into Standalone Functions/Codes and integrated with the Physical model. Thus, all the three models are looped to each other. The advantage of this co-simulation is that the user must only interact with only one tool, at the same time reaping the benefit of the other tool/s in the background. This utilizes the best of both worlds. Co-simulation is a very good technique to simulate complex subsystems by leveraging advantages of multiple Simulation tools to get faster and accurate results.
As per WHO 2018 report, pedestrian fatalities account for 23% of world road accident fatalities. Every day 850 pedestrians lose their lives in the world. As per MoRTH 2018 report, 16% of road accident fatalities are of pedestrians in India. Everyday 64 pedestrians lose their lives in India. Based on accident data, one of the most common reason for the pedestrian fatality is head injury due to primary contact from vehicle front-end structure. Pedestrian head injury performance highly depends on front-end styling, bonnet stiffness, clearance with aggregates underneath the bonnet and hard contact points. During concept stage of vehicle development, safety recommendation on front-end design is provided based on geometric assessment of the class A surface. This paper presents the novel approach of using machine-learning algorithms to predict the head injury performance at the early stage of vehicle design using the knowledge of existing vehicle simulation data and new vehicle design features. Machine learning based mathematical model has been developed considering critical design parameters such as clearance with aggregates, impact point location with respect to hard points, stiffness of bonnet as input variables and head injury criteria (HIC) as output variable from existing vehicles. Different supervised machine learning algorithms such as random forest, neural networks, logistic regression and supporting vector regression are trained and tested using available data. Subsequently, the suitable mathematical model was selected based on the model score. Identified model was able to predict the pedestrian head injury criteria (HIC) within 20% of margin of error for majority of the impact points. This approach has significant potential and provides opportunities for giving directional feedback during early stage of the vehicle development.
Currently the Automotive industry demands highly competitive product to survive in the global tough competition. The engine cooling system plays a vital role in meeting the stringent emission norms and improving the vehicle fuel economy apart from maintaining the operating temperature of engine. The airflow through vehicle subsystems like the grille, bumper, the heat exchangers, the fan and shroud and engine bay are called as front-end flow. Front end flow is crucial factor in engine cooling system as well as in determining the aerodynamic drag of vehicle. The airflow through the engine compartment is determined by the front-end vehicle geometry, the CRFM and CAC package, the engine back restriction and the engine compartment geometry including the inlet and outlet sections. This paper discusses the 1D modelling method for front-end airflow rate prediction and thermal performance by 1D method. The underbody components are stacked using heat stack and simulated in pressure mode. Software used was Siemens Sim-center Amesim.
An automatic tensioner with an asymmetric damping structure used in an engine front end accessory drive system is analyzed. An analytical model is established to calculate the hysteretic behavior of the tensioner. The contact characteristics of contact pairs are modeled and investigated for disclosing relation between contact pair, friction and hysteretic loop of an automatic belt tensioner. The presented models are validated by a torque measurement versus angular displacement of a tensioning arm. The errors between the calculation and the measurement are analyzed. The working torques of the tensioner during loading and unloading process are described by a bilinear hysteretic model and are written as a function with a damping ratio. The influence of damping structure parameters on the hysteretic torque is investigated. The method presented in this paper can be used for predicting the nonlinear characteristics of a tensioner before prototyping.
A multi-year Power System R&D project was initiated with the objective of developing an off-road hybrid heavy-duty concept diesel engine with front end accessory drive-integrated energy storage. This off-road hybrid engine system is expected to deliver 15-20% reduction in fuel consumption over current Tier 4 Final-based diesel engines and consists of a downsized heavy-duty diesel engine containing advanced combustion technologies, capable of elevated peak cylinder pressures and thermal efficiencies, exhaust waste heat recovery via SuperTurbo™ turbocompounding, and hybrid energy recovery through both mechanical (high speed flywheel) and electrical systems. The first year of this project focused on the definition of the hybrid elements using extensive dynamic system simulation over transient work cycles, with hybrid supervisory controls development focusing on energy recovery and transient load assist, in Caterpillar’s DYNASTY™ software environment. Three key off-road applications were the focus of the hybrid concept definition with an aim of understanding the system’s modular capability for the diverse off-road heavy-duty market. Core engine performance 1D and 3D simulations isolated the efficiency contributions from the downsized engine, turbocompounding, and in-cylinder thermal barrier coatings. A fuel consumption improvement range of 14 to 24% was predicted, resulting in successful project progression to the design and experimental validation phase. An overview of the experimental engine and hybrid system status concludes the discussion along with the multi-year project’s next steps.
Two-layer engine front end accessory drive systems (TEFEADS) are adopted generally by commercial vehicles due to the characteristics of the accessory pulleys, which have large torque and moment of inertia. An overrunning alternator decoupler (OAD) is an advanced vibration isolator which can reduce the amplitude of torsional vibration of alternator rotor effectively by an one-way transmission and they are more and more widely used in vehicles. This paper established a model of a generic layout of a TEFEADS with an OAD. The coupling effect between the TEFEADS, the nonlinear characteristics of OAD, the torsional vibration of crankshaft and the creeping on the belt were taken into account. A nine pulleys model was provided as a study example, the dynamic responses, which are respectively under steady and accelerating conditions, of the system were calculated by the established method and compared with the bench experiment. The influence of different belt material, the stiffness of OAD spring and the parameter of the tensioner on dynamic performances, such as the oscillation of tensioner arm and the dynamic belt tension were analyzed.
Tractor weight transfer is the most common farm-related cause of fatalities nowadays. As in India it is getting mandatory for all safety devices across all HP ranges. Considering any changes in the weight from an attachment such as Rops, PTO device, tow hook and draw bar etc. can shift the center of gravity towards the weight. center of gravity is higher on a tractor because the tractor needs to be higher in order to complete operations over crops and rough terrain. Terrains, attachments, weights, and speeds can change the tractor’s resistance to turning over. This center of gravity placement disperses the weight so that 30 percent of the tractor’s weight is on the front axle and 70 percent is on the rear axle for two-wheel drive propelled tractors and it must remain within the tractor’s stability baseline for the tractor to remain in an upright position. In our present study formulating the prediction of tractor CG by using a modified excel spreadsheet package employing the parameters of the model, tractor CG were then determined. Finally, the effects of changes in the parameters of the model were evaluated and results of the analyses indicate the changing the tractor CG about the x-axes and y-axes have an influence on the weight distribution of the tractor from front and rear wheel, whereas increasing the tractor weight percentage on the front wheel have an benefit of tractor less lifting on the front end.
As pedestrian protection tests and evaluations have been officially incorporated into new C-NCAP, more stringent requirements have been placed on pedestrian protection performance. In this study, in order to reduce the injury of the vehicle front end structure to the pedestrian's lower extremity during the collision, the advanced pedestrian legform impactor (aPLI) model was used in conjunction with the finite element vehicle model for collision simulation based on the new C-NCAP legform test evaluation regulation. This paper selected the key components which have significant influences on the pedestrian's leg protection performance based on the CAE vehicle model, including front bumper, front-cover plate, upper impact pillar, impact beam and lower support plate, to form a simplified model and conducted parametric modeling based on it. Then, the variable correlation analysis was carried out on the sample results obtained from the design of experiment (DOE), and the contribution analysis of design variables to the injury measures was discussed. The sample variables and responses were also used to construct the approximate models for further optimization studies. Taking the pedestrian lower extremity injuries as the optimization target, the front end structural parameters were matched and optimized. Finally, an optimal configuration for parameter matching of key components of the front end structure for pedestrian protection was established, which effectively improve the protection of pedestrian lower extremity.
One of the key inputs 1-D transient simulation takes is a detailed front end cooling flow map. These maps that are generated using a full vehicle Three-dimensional Computational Fluid Dynamics (3D CFD) model require expensive computational resources and time. This paper describes how an adaptive sampling of the design space allowed the reduction of computational efforts while keeping desired accuracy of the analysis. The idea of the method was to find a pattern of Design of Experiments (DOE) sampling points for 3D CFD simulations that would allow a creation of an approximation model accurate enough to predict output parameter values in the entire design space of interest. Three procedures were implemented to get the optimal sampling pattern. One of them, called Procedure #1 below employed the observations listed below, identification of the areas that would require less sampling points by analyzing approximation errors, manual reduction of the points in such areas, building an approximation model with the points left in the sampling set, and further accuracy evaluation in removed points where output parameter values are known. Input parameters identified in this study were AGS opening, fan speed and vehicle speed. The output parameters monitored were the flow through the heat exchangers radiator, condenser and transmission oil cooler. Accuracy assessments of approximations made of different point sets provided hints on the sensitivity to each of the inputs and areas where the sampling density could be reduced. Areas of the cooling flow map that required more or less sampling points density were assessed with the help of following observations. Cooling flow to heat exchangers varied linearly for AGS opening greater than 50%. Cooling flow to heat exchangers varied linearly for higher vehicle speeds in the range of 39 mph to 80 mph. For vehicle speeds greater than 65 mph, the fan speed changes played a minor role. The approximation model had bigger error for a low vehicle speed and high fan speed combinations. The approximation model worked effectively when the idle and peak vehicle speed cases where included in the sample data set. Another procedure, called Procedure #2 below used was an Optimal Latin Hypercube DOE method to sample the design space that was simulated by an accurate approximation model built with all available 3D CFD simulation results (also called Dataset A - 123 runs). The smaller DOE started with 25 sampling points was used to make another approximation model and the accuracy of the approximation was assessed against the most accurate model. The above steps were repeated in the third method, called Procedure #3 below where Isight simulations were started with a relatively small number of sampling points, extra sampling points were added in the areas where the model performed the worst and in key areas identified by the cooling flow parameter sensitivity studies mentioned above. Such additions were made with Isight Adaptive DOE procedure that allowed an efficient way to fill the least populated areas of the design space with sampling points. Both the manual DOE and adaptive DOE procedures yielded patterns that had minimal number of sampling points while providing predefined accuracy levels of the front-end cooling airflow evaluations in the entire design space.
Overall cycle time and prototype testing are significantly decreased by assessment of cooling module performance in the design stage itself. Hence, Front End Cooling and Thermal Management are essential components of the vehicle design process. Performance of the cooling module depends upon a variety of factors like frontal opening, air flow, under-hood sub-systems, module positioning, front grill design, fan operation. Effects of design modifications on the engine cooling performance are quantified by utilizing computational fluid dynamics (CFD) tool FluentTM. Vehicle frontal configuration is captured in the FE model considering cabin, cargo and underbody components. Heat Exchanger module is modelled as a porous medium to simulate the fluid flow. Performance data for the Heat Exchanger module is generated using the 1D KuliTM software. In this paper, CFD simulation of Front End Cooling is performed for maximum torque and maximum power operating conditions. Analysis results predict and plot the air flow patterns in the under-body region by obtaining velocity streamlines in the wind tunnel volume. Hot and cold air recirculation zones are identified and rectified by design changes. Temperature and velocity data for the inlet surfaces of Heat Exchanger are obtained to better describe the air flow impact. Limiting Ambient Temperature (LAT) and Intake Manifold Temperature Difference (IMTD), two important parameters which signify the cooling performance of radiator and intercooler respectively are calculated and set within the acceptance criteria. Reduction of hot air recirculation over Heat Exchanger module leads to significantly improved cooling performance. Design modifications of the front end geometry and use of different heat exchangers and fans produce better results by means of an iterative process. The methodology is validated by conducting cooling trials in the vehicle for both the operating conditions. Excellent overall correlation of more than 90% is obtained between CFD predictions and test results.
A model for a generic layout of an engine front end accessory drive system is established. The dynamic performances of the system are obtained via a numerical method. The dynamic performances consist of the oscillation angle of tensioner arm, the slip ratio of each pulley and the dynamic belt tension. In modeling the system, the hysteretic behavior of an automatic tensioner, the loaded torque of the accessory pulley versus the engine speed, the torsional vibration of crankshaft and the creep of the belt are considered. The dynamic performances of the system at steady state and under accelerating condition are analyzed. An example is provided to validate the established model. The measured results show that the torsional vibration of crankshaft is larger and the dynamic performances of the system are different under accelerating conditions, though the acceleration is small. In the end, the dynamic performances of the system using different belts with different Young’s modulus are studied by the established model.
The automatic tensioner is an important component of the engine front end accessory drive system (EFEADS). It maintains the tension of the belt steadily and reduces the slip of pulley, which is benefit for improving the life of V-ribbed belt. In this paper, an EFEADS model is established which is considering with the hysteretic behavior and the asymmetry of friction damping of a tensioner. A four-pulley EFEADS is taken as a study subject. The dynamic responses of system, such as the oscillation angle of each pulley, the slip factor of pulley, the oscillation of tensioner arm and the dynamic belt tension are analyzed with symmetric damping and asymmetric damping tensioner. Meanwhile, the influence of asymmetric damping factors of tensioner on the dynamic response of EFEADS is also investigated. The experimental results show that tensioner with an asymmetric damping can effectively reduce the oscillation angle of each pulley and the oscillation of tensioner arm, and the fluctuation of dynamic belt tension.
The generator is an important loaded component of an engine front end accessory drive system (EFEADS). With a huge moment of inertia and a highest running speed, the vibration and noise often occurs in operation, which has an effect on the service life. Thus an overrunning alternator decoupler (OAD) is used in the EFEADS for reducing the vibration of system. In this paper, a model of EFEADS with an OAD is established. The impact of the OAD on the dynamic responses of pulley of generator and the system are analyzed, and is verified by bench experiments. And the influence of parameters, such as spring stiffness, moment of inertia of generator and loaded torque on the dynamic performances of the system are studied. The influence of misalignment in pulleys on the dynamic performance of system is also discussed. The presented method is useful for optimizing the dynamic performance of system, such as the oscillation of tensioner arm and the slip ratio of the belt-generator pulley.
This research focuses on the use of Event Data Recorders (EDR) to assist in calculating speed loss or ΔV undergone by a motorcycle in a broadside type impact into a vehicle. If the struck vehicle has EDR data, this could be a useful tool in calculating motorcycle ΔV or corroborating motorcycle ΔV calculations from crush or other methodologies. Certain parameters critical to calculation of motorcycle ΔV must be considered, including the appropriate effective mass to use for the motorcycle/rider combination. This study used crash test data to determine a method of applying parameter values to accurately calculate motorcycle ΔV in a motorcycle-vehicle collision. In this study, three crash tests were performed in which a motorcycle with a dummy rider traveling in the range of 42 to 51 mph collided into the right front corner of a vehicle traveling between 5 and 16 mph. In all three tests, both the vehicle and motorcycle were instrumented with triaxial accelerometers and triaxial rate gyros. The first test involved a 2002 Kawasaki ZRX1200R traveling at 42.2 mph into the right front corner of a 2009 Chevrolet Malibu traveling at 5 mph. The impact occurred just forward of the vehicle’s right front wheel area. The second test involved a 2006 Yamaha YZF-R6 traveling at 48.1 mph into the right front corner of a 2012 Ford Focus traveling at 14 mph. The impact occurred near the vehicle’s right front headlight/bumper reinforcement area. The third test involved a 2013 Kawasaki Ninja EX300 traveling at 50.5 mph into the right front corner of a 2015 Nissan Sentra traveling at 9 mph. Again, the impact occurred near the vehicle’s right front headlight/bumper reinforcement area. In all the tests, the vehicle ACM-recorded data underreported the longitudinal ΔV in the range of 0.8-1.3 mph. Additionally, in all tests the vehicle ACM-recorded data overreported the lateral ΔV by 0.4-0.5 mph. This overreporting was present after adjustments were made for the ACM location. Overall, the EDR data was able to predict the motorcycle ΔV within a range of -5.9 mph to +3.1 mph. The underpredicted values were calculated with full rider and motorcycle weight, and the overpredicted values were calculated with half the rider weight.
Design and production of an assembly system for a major aircraft component is a complex undertaking, which demands a large-scale system view. Electroimpact has completed a turnkey assembly line for producing the wing, flap, and aileron structures for the COMAC C919 aircraft in Xi’an, China. The project scope includes assembly process design, material handling design, equipment design, manufacture, installation, and first article production support. Inputs to the assembly line are individual component parts and small subassemblies. The assembly line output is a structurally completed set of wing box, flaps, and ailerons, for delivery to the Final Assembly Line in Shanghai. There is a trend toward defining an assembly line procurement contract by production capacity, versus a list of components, which implies that an equipment supplier must become an owner of production processes. The most significant challenge faced was the amount of front end engineering work required to develop detailed assembly processes and reconcile them with the customer, who remains the actual process owner. Other challenges include aircraft maturity delays, design changes due to process definition evolution, factory environmental conditions such as dust and varying temperature gradients, and cultural and communication challenges both internal and external. The result achieved by Electroimpact is an assembly line system composed of an integration of assembly tooling, special process equipment, NC machine equipment, inspection equipment, material handling and logistics equipment: Two robotic drilling cells integrated with both stationary and mobile tooling. Integrated wing major assembly cell with manual assembly jigs and large CNC wing drilling machines. Twenty-three other manual work stations. New technology developments implemented include: A new high-curvature nosepiece on the robot end effecter to enable accurate drilling and countersinking on the LE Spar D-Nose section. A new application and delivery system for single-sided temporary fasteners for wing panel drilling. Tooling design to accommodate large temperature variations.
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