International Journal of Vehicle Performance (13 papers in press)
Integrated State & Parameter Estimation for Vehicle Dynamics Control
by Kanwar Bharat Singh, Saied Taheri
Abstract: Most modern day automotive chassis control systems employ a feedback control structure. Therefore, a real-time estimate of the vehicle handling dynamic states and tire-road contact parameters are invaluable for enhancing the performance of current vehicle control systems, such as anti-lock brake system (ABS) and electronic stability program (ESP). Today's production cars are equipped with onboard sensors (e.g. a 3-axis accelerometer, 3-axis gyroscope, steering wheel angle sensor, and wheel speed sensors) which when used in conjunction with certain model based observers can be used to identify relevant vehicle states for optimal control of comfort, stability and handling. However, some key variables such as the tire forces, road bank/grade angles, and the tire-road friction coefficient, which have a significant impact on vehicle handling performance and safety are difficult to measure using sensors already onboard vehicles. This paper introduces an integrated vehicle state estimator comprising a series of model-based and kinematic-based observers for estimating these unmeasurable states. Using an appropriate vehicle model, kinematic equations of motion and vehicle sensor data, the unknown vehicle states as well as the tire-road contact forces are estimated by implementing a series of observers arranged in a cascade structure. Key estimated signals include the vehicle side slip angle (β), tire longitudinal/lateral/vertical forces, and the tire-road friction coefficient (μ). The performance of the proposed estimators has been evaluated via computer simulations conducted using the vehicle dynamics software CarSim
Keywords: state estimation; parameter estimation; sliding mode observer (SMO); Kalman filter (KF); recursive least squares (RLS).
Numerical Parameter Characterization of a Buried Mine Blast Event with Further Emphasis on IED Shapes and Soil Bed Conditions
by Morten Rikard Jensen, Wilford Smith
Abstract: The modeling of a buried charge and its impact on vehicle structures is a complex simulation task since numerous structural variables, physical properties and numerical parameters have to be determined to provide accurate estimation of the structures response. A number of variables in question are directly related to the numerical approach chosen to perform the analysis while others relate to the overall modeling process and the detail used to describe the physical processes. Two prerequisites are required for a tool to be predictive in nature. First the tools numerical approach must be verified against the available experimental data and second, a sensitivity study of the numerical and process parameters must be performed to understand how the modeling parameters influence the model results. The emphasis of the present study covers the second prerequisite. This paper documents the results of a comprehensive sensitivity study of the structural response of a vehicle subjected to the impulse from a buried charge using the Discrete Particle Method (DPM) to model the soil and high explosive (HE) coupled to a Finite Element solver for the structure. Fourteen design variables and numerical parameters were studied requiring in excess of 1000 computational hours. The basis for the study was a blast event applied to a model of the TARDEC Generic Vehicle Hull. The response parameter was chosen to be the total blast impulse (TBI) on the structure. The non-linear transient dynamic explicit Finite Element solver used for the analysis was the IMPETUS Afea Solver
Keywords: Explicit finite element; non-linear transient dynamics; mine blast; IEDs; improvised explosive devices; blast impulse; the IMPETUS Afea Solver®; TARDEC generic vehicle hull model; iDPM; IMPETUS DPM algorithm; DPM; discrete particle method; soil and High Explosive modeling; sensitivity study.
Validation of a GPS-based vehicle mobility power model
by George Bozdech, Paul Ayers, David Irick
Abstract: Recently, military vehicles have been equipped with hybrid, diesel-electric drives to improve fuel efficiency and stealth capabilities, and these vehicles require accurate power duty cycle estimates. A GPS-based mobility power and duty cycle model was developed and is used to predict the vehicle power requirements. The dynamic vehicle parameters needed to estimate the forces and power developed during locomotion are determined from the GPS tracking data. Controlled tests were performed and the predicted mobility power values predicted from a GPS receiver were compared to the measured drivewheel power estimated from engine data transmitted on the vehicle's Controller Area Network (CAN). The results from the validation tests indicated that the model was reasonably accurate in predicting the average power requirements of the vehicle.
Keywords: GPS; mobility; power; model; CAN; duty cycle; validation; military vehicle; testing.
Noise exposure to tractor drivers in field operations
by Lalremruata , Krishna N. Dewangan, T. Patel
Abstract: Tractor drivers are exposed to varying intensity of Noise. Exposure to loud noise adversely affects human health and thus the quality of life. A study was performed to investigate equivalent sound pressure level (Leq) in tractors at the drivers ear to assess noise exposure in tillage operations. Six models of tractors and five different tillage implements namely mould board plough, disc plough, rotavator, disk harrow and duck foot cultivator were selected for measurements of Leq. Measurements were performed at three different forward speeds. Noise exposure to the drivers was compared with the permissible exposure limits (PELs) in OSHA (1983) and NIOSH (1998). The results showed that noise intensity at the drivers ear level varied between 91.7 and 97.5 dB(A). Increase in forward speed of operation increased noise intensity irrespective of tractors and implements. Tractors, type of implements and forward speed has significant (p<0.001) effect on noise exposure. Noise exposure was considerably higher with rotavator as compared with other tillage implements while noise exposure was comparable in other tillage implements. Noise exposure to the tractors drivers exceeded the PEL for 8 h operation. According to PELs in OSHA and NIOSH, the tractors should be operated nearly 2 and 7 h, respectively.
Keywords: Sound pressure level; noise intensity; noise spectrum; tillage implement; permissible exposure limits.
Whole-body vibration biodynamics - a critical review: I. Experimental biodynamics
by Subhash Rakheja, Krishna Dewangan, Ren Dong, Pierre Marcotte
Abstract: In the framework of whole-body vibration (WBV), biodynamics refers to the biomechanical responses of the human body, including its substructures, to impressed oscillatory forces or motions. The biodynamic responses of the human body to WBV form an essential basis for an understanding of the mechanical-equivalent properties of the body and the potential injury mechanisms, developments in frequency-weightings and enhanced design tools of systems coupled with the human operator. In this first part, the biodynamic responses obtained experimentally in terms of to-the-body and through-the-body functions, are critically reviewed and discussed to highlight the influences of various contributory factors, such as those related to posture, body support, anthropometry and nature of vibration, together with the range of experimental conditions employed in different studies. The reported data invariably show strong and highly complex, nonlinear and coupled effects of the majority of the contributory factors. It is shown that the reported studies often conclude conflicting effects of many factors, such as posture, gender, vibration and support conditions.
Keywords: apparent mass; seat-to-head transmissibility; absorbed power; driving point mechanical impedance; contributory factors; gender and anthropometric effect; sitting posture; type; magnitude and frequency of vibration.
Whole-body vibration biodynamics - a critical review: II. Biodynamic modelling
by Subhash Rakheja, Krishna Dewangan, Ren Dong, Pierre Marcotte, Anand Pranesh
Abstract: Biodynamic models of seated body exposed to whole-body vibration are considered important for design of vibration control devices and anthropodynamic surrogates for efficient performance assessments of vibration isolators. In this second part, the reported biodynamic models of the seated body are briefly reviewed together with the different modeling approaches. The models are identified from target functions derived from the measured biodynamic responses, reviewed in the first part of this paper. Relationships between different target functions are discussed together with the merits and limitations of different modeling approaches. Further efforts are needed for developing representative target functions for deriving reliable models for designing engineering interventions and for predicting potential health and comfort effects.
Keywords: biodynamic models; biodynamic response functions; whole-body vibration; model parameters identification.
Wear experiment of ball joints under multi-axis loads using special developed fixtures
by Guosheng Han, Wen-Bin Shangguan, Guofeng Zheng, Zhihong Yin
Abstract: A method for measuring wear performance of a ball joint is proposed, and a method for designing a special fixture for ball joint wear measurement with four-axis is presented. Based on the proposed methods, a test rig for measuring wear performance of a ball joint is developed and manufactured. The movement at each axis of the fixture is independent based on analysis of movement characteristics and degrees of freedom (DOF) at each axis of the measured ball joint. The off-line control strategy to the special fixture is used to reproduce the load spectrum of the ball joint acquired in the real load conditions. One ball joint taken from an automotive suspension is used to measure the wear characteristics using the developed test fixture and hydraulic actuators. The wear properties of the ball joint before and after experiment are compared and analyzed. It is shown that the developed fixture and the proposed test procedures can be used for the wear measurement of a ball joint with standard force or torque actuators at lab. The analytical and designed method for the developed test fixture can be used for designing other test fixtures with multi-axis loadings.
Keywords: Ball joint; Four-axis wear test fixture; Motion decoupling; Off-line control.
Review on Automatic Transmission Control in Electric and Non-Electric Automotive Powertrain
by Sireesha Tamada, Debraj Bhattacharjee, Pranab K. Dan
Abstract: This study presents an overview of control logic development for automotive transmission in both electric and non-electric powertrain. The control of automotive power transmission determines the shift quality that is attaining smoother shifting, leading to better drivability which rather important. The steady upswing of electronic and embedded systems has supplanted mechanical controls. The transition of actuation technology from mechanical to electromechanical type also propels the development of electronic controls in the vehicle. The electronic Transmission Control Unit (TCU) governing automation of gear-shifting process in the transmission system, betters the driving experience due to improved shifting quality. There has been a rising demand for automatic gear shifting owing to its potential for uninterrupted gear shifting or also called power shifting. Gear shifting strategy and control are central to quality shifting process. Hence this work presents state of the art on controls for gear shifting and identifies the scope of further research.
Keywords: Automotive transmission; Transmission control; Gear Shifting; Shift quality; Virtual Electronic controller simulator; Electric Powertrain; Non-Electric Powertrain.
Measurement and Analysis of Performance of Mining Dump Trucks
by Pawan Kumar Yadav, Suprakash Gupta, Deepak Kumar
Abstract: Dump trucks are one of the widely used and capital-intensive heavy earth moving equipment in the mining industry. High-performance rate, good measurement practices and continuous monitoring of equipment performance are mandatory for the high-cost systems to be in the business. Defining the metrics of a performance measure (PM) is essential to monitor the performance of these equipments. This research proposes a methodology for measuring the performance of a dump truck. The proposed PM is derived from the Overall Equipment Effectiveness (OEE), a widely used PM in industrial and manufacturing industries, through modification of metrics. The modified PM is more comprehensive and incorporates the environmental aspects into the performance metrics. Commonly used PMs are based on the internal losses calculation, i.e. availability, performance, and quality losses; which neglected the operational effect beyond the system boundary, i.e. external losses. The proposed PM presents an approach that unites time performance, capacity performance as well as environmental performance. It has been illustrated with a case study in a large surface coal mine. Operational data have been analysed with SPSS. The findings are as follows
i. Dump truck performance decreases with its age,
ii. Availability and utilisation are the major cause of concern for poor performance
iii. Group-B dump trucks perform better than Group-A dump trucks.
The above findings are useful information in decision making.
Keywords: Dump truck; Performance Measurement; Environmental performance; Overall Equipment Performance Indicator (OEPI).
Special Issue on: Multibody System Algorithms in Vehicle Dynamics and Virtual Prototyping
Wheelrail wear simulation and rail cant optimisation based on railway vehicle dynamics
by Wei Li, Pu Wang, Shuguo Wang, Daolin Si
Abstract: A numerical prediction model for the wheelrail wear development on heavy-haul railway is established herein, and a corresponding programme is written using MATLAB. Using Archards material wear theory, wear distributions in the wheelrail contact patch and along the rail profile are evaluated via vehicletrack dynamics simulation and wheelrail rolling contact analysis. In the vehicle dynamics model, various structural components and complex nonlinear interactions between components are precisely simulated to guarantee consistency with reality. The established model is employed to study the influences of rail cant on the wheel-rail wear distribution and development. The following two main conclusions are drawn. On straight railway section, the wheelrail contact region and wear distribution become unreasonable when the rail cant exceeds 1/20. On curved section, the influences of rail cant on the wear of the inner and outer rails are different. The changes of rail cant also obviously impact the changing rules of wear with the vehicle speed. A rail cant of 1/30 is recommended for the curved section of heavy-haul railway.
Keywords: heavy haul railway; vehicle-track dynamics; wheel–rail contact; wear; numerical simulation; rail cant; optimisation.
Study the Dynamic behaviour of seven DOF of full car model with semi-active suspension system
by Hemanth Krishna, Shamanth Vasanth, Devaraj Sonnappa, Hemanta Kumar, Gangadharan KV
Abstract: This paper presents an investigation on the ride comfort and road-holding performance of a vehicle equipped with the semi-active suspension system. The full car semi-active suspension model with 7 degrees of Freedom (7 DOF) system is adopted for the study and a fuzzy-logic control strategy is considered for minimizing the effect of road disturbance on vehicle performance. The responses of a vehicle have been analyzed under the Indian average random road profile (ISO8608) against the conventional passive suspension system. The performance of the semi-active suspension system is evaluated by heave, roll and pitch acceleration of the vehicle body around its center of gravity. The performance of a vehicle with the semi-active suspension system has been compared with the response conventional passive suspension system. The result specifies that, the semi-active suspension system with a Fuzzy-logic controller reduces around 43 % of vibration amplitude at the resonance frequency of vehicle than the passive suspension system.
Keywords: Full car; MR damper; Modified Bouc-wen; NSGA-II; optimization; fuzzy logic and Indian average road.
Research on Hierarchical Control Strategy of Electromagnetic Active Mounting System
by Zheming Chen, Heng Wang, Chenguang Lai
Abstract: In order to improve the vibration isolation performance of the automotive powertrain mounting system, a hierarchical control strategy is proposed according to the structural characteristics of the electromagnetic active mounting system and the influence of the dynamic characteristics of the actuator on the system control accuracy. Based on the analysis of the active mounting system 3 degree-of-freedom (DOF) 1/4 vehicle, the mathematical model of the mounting system and the electromagnetic actuator control circuit is derived. Guided by hierarchical control strategy, upper and lower controllers are designed for mount part of the active mounting system and actuator circuit respectively. The upper mounting controller is under LQR control with strong adaptability, fine robustness and easy implementation, and the weight coefficient of its performance index is optimized by genetic algorithm. The lower part of the actuator circuit is under simple and practical PID control and its parameters are optimized through particle swarm optimization algorithm. To verify the effectiveness of the control strategy, two typical working conditions are set for simulation research with the system input of the joint excitation of the engine and pavement. The results show that compared with the active mounting system under conventional control, the system designed according to the hierarchical control strategy can control different working conditions of the vehicle more precisely, which not only improves the vibration isolation performance of the powertrain mounting system to a certain extent, but also renders a better robustness and force tracking property.
Keywords: Automotive engineering; powertrain; electromagnetic actuator; active mount; LQR control; genetic algorithm; PID control; particle swarm optimization; hierarchical control; simulation analysis.
Special Issue on: Recent Advances in Energy-efficient Research for Vehicle Performance Improvement
Research on regenerative braking strategies for hybrid electric vehicle by co-simulation model
by Han Guo, Jianwu Zhang, Wenran Geng, Huijun Cheng, Haisheng Yu
Abstract: Regenerative braking is an important factor in improving hybrid electric vehicle fuel economy. This paper presents the simulation modelling of a power-split hybrid electric vehicle with different regenerative braking strategies. A co-simulation model is used to enhance the simulation capability for the hybrid vehicle performance and development of control strategy. AMESim is used to model the complex physical components including engine, transmission, motors, battery and hybrid vehicle, and the physical model is integrated with control model established by MATLAB/Simulink, which is required to operate the vehicle and the regenerative braking system through standard drive cycles. Simulation results show that a regenerative braking control strategy can recuperate significant amounts of energy. Vehicle fuel economy in EV and HEV modes is improved significantly by coupling the proposed regenerative braking strategy.
Keywords: hybrid electric vehicle; regenerative braking; energy management; AMESim; MATLAB/Simulink.