Are EDR Devices Undoubtedly Helpful in the Reconstruction of a Road Traffic Accident?

All over the world, the vehicles introduced now into the market are usually provided with EDRs (Event Data Recorders), intended to measure and record the parameters that characterise the vehicle motion in the pre-, during-, and post-accident phases. The EDRs are to facilitate the description and reconstruction of possible road accidents. They are patterned on aircraft “black boxes” (flight recorders). Many of them have simplified design, disregarding three (of six) vector components that describe the motion of the vehicle body solid. In the paper presented, the authors used simulation models built by themselves to represent motor vehicle dynamics and the reconstruction of vehicle trajectory and velocities based on records obtained from two EDR types: “aircraft” one (EDR1) and “simplified” one (EDR2). Using a simulation method, they examined the impact of the said simplifications mentioned above on the quality of reconstruction of vehicle motion for four typical manoeuvres in road traffic. The calculation results obtained for input data adopted to rep-resent a medium-class passenger car have shown that the simplifications may cause considerable reconstruction errors. This particularly applies to the manoeuvres where significant changes took place in the roll and pitch angles of the vehicle body solid (to which the EDR was fixed) or where the changes were characterised by absence of symmetry in the parameters that describe the manoeuvre and by the constant sign of the vehicle body roll angles.

Analisis Kekuatan Stabilizer Bar (Anti-Roll Bar) Pada Kendaraan Roda Empat Menggunakan Bantuan Software Solidworks

Abstrak Stabilizer bar berfungsi mengurangi besarnya sudut rolling, sehingga diharapkan kendaraan lebih stabil. Tujuan yang ingin dicapai dari penelitian ini adalah mengetahui kekuatan stabilizer bar akibat body roll kendaraan dengan pemodelan dan simulasi serta analisis menggunakan bantuan software solidworks. Metode yang digunakan adalah mengidentifikasi karakteristik fisik, beban, tumpuan dan material yang digunakan untuk proses pemodelan serta simulasi sederhana menggunakan software solidworks sehingga dapat memperoleh tegangan geser dan faktor keamanan. Sebagai pembanding terhadap model dan simulasi solidwork, tegangan geser maksimum yang terjadi dihitung secara manual berdasarkan momen puntir dan momen lentur yang bekerja secara simultan dalam stabilizer bar. Hasil penelitian ini menunjukkan bahwa ketika kendaraan mengalami body roll sebesar 3,51° dimana stabilizer bar terpuntir 2,62° dan mengalami tegangan geser dan faktor keamanan dari perhitungan manual, yaitu 52,47 MPa dan 9,39 untuk beban statis, 104,94 MPa dan 4,69 untuk beban dinamis. Berdasarkan analisis menggunakan software solidwork tegangan geser dan faktor keamanan, yaitu 50,05 MPa dan 8,96 untuk kondisi statis, 100,1 MPa dan 4,48 untuk kondisi dinamis. Berdasarkan prediksi menggunakan persamaan regresi linier, maka sudut body roll kritis yang dapat dicapai adalah sebesar 45,99° ketika stabilizer bar mulai mengalami deformasi plastis. Kata kunci : Stabilizer Bar, Anti-Roll Bar, Solidworks Abstract The stabilizer bar functions to reduce the amount of rolling angle, so that the vehicle is expected to be more stable. The purpose of this research is to determine the strength of the stabilizer bar due to vehicle body roll by modeling and simulation and analysis using Solidworks software. The method used is to identify the physical characteristics, loads, supports and materials used for the modeling process and simple simulations using solidworks software so as to obtain shear stress and safety factors. As a comparison to the solidwork model and simulation, the maximum shear stress that occurs is calculated manually based on the torsional moment and the bending moment that work simultaneously in the stabilizer bar. The results of this study indicate that when the vehicle experiences a body roll of 3.51 ° where the stabilizer bar is twisted 2.62 ° and experiences shear stress and safety factors from manual calculations, namely 52.47 MPa and 9.39 for static loads, 104.94 MPa and 4.69 for dynamic loads. Based on the analysis using solidwork shear stress software and safety factors, namely 50.05 MPa and 8.96 for static conditions, 100.1 MPa and 4.48 for dynamic conditions. Based on predictions using linear regression equations, the critical body roll angle that can be achieved is 45.99 ° when the stabilizer bar begins to undergo plastic deformation. Keywords : Stabilizer Bar, Anti-Roll Bar, Solidworks

Rollover Prevention and Motion Planning for an Intelligent Heavy Truck

It is very necessary for an intelligent heavy truck to have the ability to prevent rollover independently. However, it was rarely considered in intelligent vehicle motion planning. To improve rollover stability, a motion planning strategy with autonomous anti rollover ability for an intelligent heavy truck is put forward in this paper. Considering the influence of unsprung mass in the front axle and the rear axle and the body roll stiffness on vehicle rollover stability, a rollover dynamics model is built for the intelligent heavy truck. From the model, a novel rollover index is derived to evaluate vehicle rollover risk accurately, and a model predictive control algorithm is applicated to design the motion planning strategy for the intelligent heavy truck, which integrates the vehicle rollover stability, the artificial potential field for the obstacle avoidance, the path tracking and vehicle dynamics constrains. Then, the optimal path is obtained to meet the requirements that the intelligent heavy truck can avoid obstacles and drive stably without rollover. In addition, three typical scenarios are designed to numerically simulate the dynamic performance of the intelligent heavy truck. The results show that the proposed motion planning strategy can avoid collisions and improve vehicle rollover stability effectively even under the worst driving scenarios.

Body roll amplitude and timing in backstroke swimming and their differences from front crawl at the same swimming intensities

The current study investigated body roll amplitude and timing of its peak in backstroke and compared them with front crawl swimming. Nineteen anatomical landmarks were digitised using 80 swimming trial videos (ten swimmers × two techniques × four intensities) recorded by two above- and four below-water cameras. One upper-limb cycle was analysed for each trial, and shoulder and hip roll, whole-body roll (WBR), and WBR due to the buoyant torque (WBRBT) were obtained. Main effects of intensity and technique on the amplitude and timing to reach the peak in those variables were assessed by two-way repeated-measures ANOVA. Swimmers decreased their WBRBT amplitude with an increase in the intensity in both techniques (p ≤ 0.005). The same result was observed for the amplitude of WBR, shoulder roll, and hip roll only in front crawl (p ≤ 0.017). Swimmers maintained the timing of peak WBRBT in both techniques, while they shifted the timing of WBR and hip roll peak toward the beginning of the cycle when increasing the intensity in front crawl (p ≤ 0.017). In conclusion, swimmers maintain the amplitude of WBR, shoulder roll, and hip roll in backstroke when the intensity increases, whereas they reduce the amplitude of all rolls in front crawl.

Peer-to-Peer Learning: The Impact of Order of Performance on Learning Fundamental Movement Skills Through Video Analysis With Middle School Children

Purpose: Through video analysis, this paper explores the impact that order of performance has on middle school students’ performance of fundamental movement skills within a peer-to-peer learning model. Order of performance refers to the order in which a student performed a skill while paired up with a peer. Method: Using a mobile application, Move Improve®, 18 students (eight males and 10 females) completed a standing jump and hollow body roll in partners assigned to order of performance (evaluator/performer). An independent samples t test was conducted to evaluate the differences in the mean scores between students who performed first and those who performed second for each skill. Results: There was a significant difference in standing jump scores (p < .01), where students who performed second had a higher average score than their peers who went first. Although not statistically significant (p = .293), results for hollow body roll also showed a similar performance pattern for students who went second compared with those who performed first. Conclusion: The order of performance within a peer-to-peer learning model may have a significant effect on performance scores for standing jump but not for hollow body roll. Reasons for the discrepancy may be due to a combination of skill familiarity, skill complexity, and training of observational learning.

DESIGN AND SIMULATION OF TORSION BAR(ARB) FOR FSAE USING MATLAB

Formula SAE is a student design competition organized by SAE International (previously known as the Society of Automotive Engineers, SAE). The concept behind Formula SAE is that a fictional manufacturing company has contracted a student design team to develop a small Formulastyle race car. The prototype race car is to be evaluated for its potential as a production item. Each student team designs, builds and tests a prototype based on a series of rules, whose purpose is both ensuring on-track safety and promoting clever problem solving. An anti-roll bar is a part of automobile suspensions that helps reduce the body roll of a vehicle during fast cornering or over road irregularities. It connects opposite wheels together through short lever arms linked by a torsion spring. A sway bar increases the suspension's roll stiffness—its resistance to roll in turns, independent of its spring rate in the vertical direction. In this research paper, calculation for the anti-roll bar mechanism will be simpler, and more accurate than hand calculations. Calculation was done using MATLAB and further analysis using FEA in ANSYS.

An LQG Controller Based on Real System Identification for an Active Hydraulically Interconnected Suspension

Rollover prevention is always one of the research hotspots in vehicle design. Active hydraulically interconnected suspension (HIS) is a promising technology to reduce vehicle body roll angle caused by different driving inputs and road conditions. This paper proposes a novel actuator of the active HIS system. The actuator consists of two cylinders, a ball screw, and only one motor. The actuator proposed can reduce the number of motors needed in the system. Meanwhile, forced vibration identification (FVI) is used to identify the transfer function of a half-car physical model and a Kalman state observer is applied to eliminate the influence of sensor noise. The FVI method can eliminate most model uncertainties and hidden variables. Aggressive and moderate optimal linear quadratic Gaussian (LQG) methods are implemented to control the motion of the vehicle body based on the identified transfer function of the physical model. The performance of an active HIS system with an aggressive and moderate LQG controller is compared with that of a passive HIS system. The effectiveness of the LQG controller is validated by simulation and experimental results. Also, the obtained results show that the stabilization speed of the active HIS system is 20% faster than that of the passive HIS system and the roll angle can be reduced up to 55% than that of the passive HIS system.

Role of Body Roll in Caravan Fishtailing

During towing of a caravan or trailer it is not uncommon that the trailer sways back and forth as a result of steering input, crosswind or one of many other causes. Normally there is sufficient damping in the oscillations to realign the trailer with the tow vehicle. On some occasions the swaying enters an uncontrollable phase where the sway amplitude increases at each cycle. This paper examines the contribution of body roll of caravans to the out-of-control sway. The paper proposes resonance of fundamental body roll frequency with the sway frequency as a significant contributing factor. It also proposes that body roll can control sway amplitude helping to explain the out-of-control condition. There are some keys offered that may interest caravan manufacturers and caravan owners alike.