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Viewing 151 to 180 of 9920
Technical Paper
2014-04-01
Tae-Sang Park, Sungho Jin, Jeon IL Moon, Seung-Han Yang
Abstract As is well known, the brake systems of vehicles are used in order to decelerate or stop the vehicle while the driving. The operational principle of the brake is the conversion of kinetic energy into thermal energy. In this case, the thermal energy is released to the atmosphere. Recently, electromechanical brakes (EMB) were developed in order to replace hydraulic brake calipers. Such brake-by- wire systems are composed of an electronic pedal, electronic control unit (ECU), wire, and an electromechanical caliper. A typical electromechanical brake is similar to existing floating brakes. In other words, an inner pad pushes out one side of a disc driven by the energy of a motor; by means of a screw-thread gear. Then, the caliper slides in the opposite direction by reaction force and moves the outer pad toward the other side of the disc. Then pads clamp both sides of the rotating disc and stop the wheel. While effective, this design has the problem that there is a difference in the wear of the inner and outer pads.
Technical Paper
2014-04-01
Changxin Wang, Wenku Shi, Qinghua Zu
Abstract Aiming at the difficulty of sovling the stiffness calculation of taper-leaf spring with variable stiffness, a combined method was proposed, which combine superposition method and finite difference method. Then the calculation results of different differential segments were compared with experimental results. The compared results show that the proposed method is effective and simple. So it has some practical significance in designing the taper-leaf spring. In addition, based on the stiffness test of the taper-leaf spring, the proper adjustments to the correction factor of the single parabolic leaf spring stiffness formula was recommended(ξ =0.92-0.96).
Technical Paper
2014-04-01
Ovun Isın, Ilyas Istif, Deniz Uzunsoy, Feray Guleryuz
Abstract The brake friction materials in an automotive brake system play an important role in the overall braking performance of a vehicle. Metal Matrix Composites (MMCs) have been widely investigated and applied due to their advantages of improved strength, stiffness and increased wear resistance over the monolithic alloys in automobile industries. In this paper, Al/B4CP and Mg/B4CP composites were compared to find a suitable candidate material for automotive disk brake application, in terms of wear behavior results of the materials. In addition, the experimental data was also used to model this behavior by identification. The measured tangential force was considered as the input parameter, whereas the weight loss as the output parameter. Preliminary results of this work showed that B4CP addition improved wear resistance of both aluminum and magnesium matrix composites. Additionally, the study pointed out that identified models provide a reliable and cost effective tool for wear prediction.
Technical Paper
2014-04-01
Romeo Sephyrin Fono-Tamo
Abstract The development of a non-asbestos automotive brake pad using palm kernel shell (PKS) as friction filler material is presented. This was with a view to exploiting the characteristics of PKS, which are otherwise largely deposited as waste from palm oil production, to make substitution for asbestos which has been found to be carcinogenic. Two sets of brake pads with identical ingredients but using either PKS or asbestos as base material were produced, following standard procedures employed by a commercial brake pad manufacturer. The physical, thermal, mechanical and the wear characteristics of the PKS-based brake pads were evaluated, compared with the values for the asbestos-based brake pads, and weighted against established recommendations for friction materials for road vehicle brake pads. The PKS based brake pad was characterized by 32.34 Brinell hardness number; 0.62%, swell and growth; 3375 N/s, bonding to back plate, and phase change at 689.5°C. The coefficient of friction of the experimental brake pad on cast iron was 0.43; whilst, wear rate was 9.17 E-5 g/min and exhibiting a third order polynomial with run-in time.
Technical Paper
2014-04-01
Diana Hernandez-Alcantara, Luis Amezquita-Brooks, Ruben Morales-Menendez
Abstract Semi-active suspension systems aim to improve the vehicle safety and comfort. For these systems control laws are required to achieve the desired performance improvements. On the other hand, the instrumentation of the vehicle suspension typically consists only in accelerometers, which are used to measure the vertical accelerations. However, velocities and/or displacements are required to implement the most common control algorithms for semi-active suspension systems. For instance, Skyhook and Groundhook controllers require the knowledge of the suspension vertical velocities. In this article several vertical velocities estimation approaches are studied and compared. In practical applications, it is common to use simple integrators to estimate these variables; nonetheless, it is well known that integrator-based estimations present errors due to drift. In applications where high performance is required, a better estimation of the state variables of the suspension system is essential.
Technical Paper
2014-04-01
Swapnil S. Kulkarni, Muragendra Magdum, Ravi B.
Abstract Automotive shock absorber shims are subjected to deformation while generating the pressure differential across the rebound and compression chambers. Considering the contact, large deflection, and material this shim stack deformation will be nonlinear throughout the working velocity of shock absorbers. The deformation of shim stack mainly depends on number and geometry of deflection disk, number and geometry of ports, and clamping disk geometry on which shims are rested. During the rebound and compression stroke of the shock absorber, the oil flows through the piston and base valve ports. High pressure oil developed during mid and high velocity of shock absorber results in deflection of shim stack in piston and base valve assembly. This deflection leads to oil leakage through the shim stack which results in change in damping force by the shock absorber. The fluid pressure from the flow passage (well) acting over surface area of shim differs while causing an elastic bending of the shims.
Technical Paper
2014-04-01
Hiroki Taniguchi, Takeshi Kimura, Yuya Takeda, Taku Suzuki, Akihiro Kaneko, Tomohiro Jinbo
Abstract This paper describes a control method to improve straight-line stability without sacrificing natural steering feel, utilizing a newly developed steering system controlling the steering force and the wheel angle independently. It cancels drifting by a road cant and suppresses the yaw angle induced by road surface irregularities or a side wind. Therefore drivers can keep the car straight with such a little steering input adjustment, thus reducing the driver's workload greatly. In this control method, a camera mounted behind the windshield recognizes the forward lane and calculate the discrepancy between the vehicle direction and the driving lane. This method has been applied to the test car, and the reduction of the driver's workload was confirmed. This paper presents an outline of the method and describes its advantages.
Technical Paper
2014-04-01
Ken Archibald, William Schnaidt, Rick Wallace, Kyle Archibald
Abstract SAE J2562 defines the background, apparatus and the directions for modifying the Scaled Base Load Sequence for a given a wheel rated load for a wheel design. This practice has been conducted on multiple wheel designs and over one hundred wheel specimens. All of the wheels were tested to fracture. Concurrently, some of the wheel designs were found to be unserviceable in prior or subsequent proving grounds on-vehicle testing. The remainder of the wheel designs have sufficient fatigue strength to sustain the intended service for the life of the vehicle. This is termed serviceable. Using the empirical data with industry accepted statistics a minimum requirement can be projected, below which a wheel design will likely have samples unserviceable in its intended service. The projections of serviceability result in a recommendation of a minimum cycle requirement for SAE J2562 Ballasted Passenger Vehicle Load Sequence.
Technical Paper
2014-04-01
Jongchol Han, Zong Changfu, Zhao Weiqiang
Abstract This article focuses on the research of control algorithm and control logic for the pneumatic EBS (Electronic Braking System) of commercial vehicle. An overall technical program was proposed which develops conventional braking and emergency braking for commercial vehicle EBS. According to the overall scheme, the methods of vehicle state estimation and driver's braking intention were determined, modeling and simulation for key components of commercial vehicle EBS were then carried out. This lead to the development of deceleration control, braking force distribution, brake assist and ABS control. Simulation models for key components of EBS and control strategy were validated through hardware-in-the-loop simulation tests. Simulation results show that the control strategy improves vehicle braking stability and vehicle active safety.
Technical Paper
2014-04-01
Mario Milanese, Ilario Gerlero, Carlo Novara
Abstract The vehicle sideslip angle is one of the most important variables for evaluating vehicle dynamics. The potential value of such a variable for obtaining significant improvements over current stability control systems is widely recognized. However, its direct measurement requires the use of complex and expensive devices which cannot be used in production cars. Large research efforts has been devoted to the problem of estimating the sideslip angle from other variables currently measured by standard Electronic Stability Control (ESC) sensors. However, at the best of author's knowledge, until now no application to production cars is known. In this paper, a new sideslip angle estimation technology is presented. Based on the innovative DVS methodology recently developed by the authors, a software algorithm, indicated as DVS/SA (Direct Virtual Sensor of Sideslip Angle), is designed, which estimates the sideslip angle from measurements of the yaw rate, lateral and longitudinal acceleration, wheel speed, steering angle, available from ESC sensors of most present production cars.
Technical Paper
2014-04-01
Yang Qi, Nenggen Ding, Feng Gao, Guoyan Xu
Abstract This paper develops a control strategy for tractor semi-trailers by active trailer steering, aiming at minimizing the sweep width of the vehicle at low speeds. The metric of sweep width is defined to evaluate the maneuverability of tractor semi-trailers under a circular motion with constant speeds. The active steering angle of the trailer for each given front wheel steering angle of the tractor is determined to minimize the sweep width, based on solution of equilibrium equations of both the tractor and the trailer in the yaw plane at a very low speed such as 5 km/h. The two steering angles of the tractor and the trailer are fitted to form an open-loop active-steering control algorithm. A nonlinear tractor semi-trailer system model is built for co-simulation purpose by using TruckSim and MATLAB/SIMULINK to evaluate the active trailer steering algorithm. Simulation results show that, under the low-speed roundabout and double lane change maneuvers, the active trailer steering controller can significantly reduce the sweep width and thus improve the low-speed maneuverability.
Technical Paper
2014-04-01
Shinhoon Kim, John McPhee, Nasser Lashgarian Azad
Abstract A compact sized vehicle that has a narrow track could solve problems caused by vehicle congestion and limited parking spaces in a mega city. Having a smaller footprint reduces the vehicle's total weight which would decrease overall vehicle power consumption. Also a smaller and narrower vehicle could travel easily through tight and congested roads that would speed up the traffic flow and hence decrease the overall traffic volume in urban areas. As an additional benefit of having a narrow track length, a driver can experience similar motorcycle riding experience without worrying about bad weather conditions since a driver sits in a weather protected cabin. However, reducing the vehicle's track causes instability in vehicle dynamics, which leads to higher possibility of rollovers if the vehicle is not controlled properly. A three wheel personal vehicle with an active tilting system is designed in MapleSim. The vehicle is driven by constant rotational input which is applied to the rear wheel.
Technical Paper
2014-04-01
Anthony Barkman, Kelvin Tan, Arin McIntosh, Peter Hylton, Wendy Otoupal-Hylton
This paper discusses a project intended as a design study for a team of college students preparing for careers in motorsports. The project's objective was to conduct a design study on the possible redesign of the suspension for a dirt-track sprint car. The car examined was typical of those which race on one-quarter to one-half mile dirt oval tracks across the United States. The mission of this concept study was to develop a different configuration from the traditional torsion bar spring system, for the front end. The design included moving the dampers inboard with the addition of a rocker to relate the movement through the front suspension system. For the rear end, components were designed to allow the radius rod to be adjustable from the cockpit, thus providing the driver with adjustability to changing track conditions. The project goal was to design functional front end and rear end changes that could provide a positive impact on handling as well as keeping the system easy to replace in a short period of time.
Technical Paper
2014-04-01
Xiaomin Lin, Nenggen Ding, Guoyan Xu, Feng Gao
Abstract Most tractor-semitrailers are fitted with multi-axle trailers which cannot be actively steered, and such vehicles with an articulated configuration are inclined to exhibit instability such as trailer swing, jack-knifing, and rollover at high speed. Proposed in this paper is an optimal control of the yaw stability of tractor-semitrailers at high speed by applying an active trailer's steering angle. An optimal control algorithm is designed by employing a 3-DOF vehicle model in the yaw plane. The optimal linear quadratic regulator (LQR) approach is used with a cost function including sideslip angles, yaw rates of both tractor and trailer, and trailer's steering angle. The yaw stability at the high speed is also quantified by the dynamic performance measurements of lateral path deviation, hitch angle and rearward amplification (RA). The algorithm is evaluated by co-simulations using TruckSim and Matlab/Simulink softwares. Simulation results under double lane change maneuvers show that trailer swing and jack-knifing are suppressed with a small path-tracking error and it is concluded that the optimal control of semi-trailer steering can improve the yaw stability at high speed.
Technical Paper
2014-04-01
Jie Ni, Lifu Wang
Abstract In this paper, a torsion-eliminating Hydraulically Interconnected Suspension (THIS) is proposed for the first time to reduce the undesired articulation (warp) stiffness of a two-axis vehicle. The dynamic characteristics of a typical sport utility vehicle (SUV) fitted with the THIS is investigated in the frequency domain. The equations of motion of the coupled mechanical and hydraulic sub-systems are presented. The vehicle basic mechanical sub-system is modeled as a 7 degrees of freedom (DOF) mass-spring-damper system. The hydraulic impedance method is employed to model the fluid sub-system. The relationships between the dynamic fluid states, i.e. pressures and flows, are determined by transfer matrices. Then the mechanical and hydraulic sub-systems are coupled through the mechanical-fluid boundary conditions. Based on fluid hydraulic impedance method, the characteristic equations of this mechanically and hydraulically coupled system are derived with a state vector including the displacements and velocities of mechanical system and the pressure at the mechanical-hydraulic boundary section.
Technical Paper
2014-04-01
Yang Liu, Zechang Sun, Wenbin JI
Abstract A brake pedal stroke simulator for Electro-hydraulic Braking System (EHBS) was developed to ensure the comfort braking pedal feel for the brake-by-wire system. An EHBS with an integrated master cylinder was proposed, and a composite brake pedal stroke simulator was designed for the EHBS, which was comprised of two inline springs and a third parallel one. A normally closed solenoid valve was used to connect the master cylinder booster chamber and the stroke simulator. The suitable brake pedal stroke was achieved by three stages of these springs' compression, whereas the solenoid valve was shutdown to enable mechanical control of the service brakes when electrical faults appeared. The pedal stroke simulator and the EHBS were modeled in MATLAB/SIMULINK-AMESim, and then the pedal stroke characteristic including the depressing and releasing process and its influencing factors, namely the preload force of the return spring, the cross-sectional area of the solenoid valve orifice, piston damping coefficient, and the pressure booster ratio were analyzed during the normal and failsafe mode.
Technical Paper
2014-04-01
Prashanth KR. Vaddi, Sandeep Vinjamuri, Kumar Cheruvu
Abstract Advanced research in ABS (Anti-lock Braking System), traction control, electronic LSD's (Limited Slip Differential) and electrical powertrains have led to an architecture development which can be used to provide a controlled yaw moment to stabilize a vehicle. A steer assistance mechanism that uses the same architecture and aims at improving the vehicle response to the driver steering inputs is proposed. In this paper a feed-forward approach where the steering wheel angle is used as the main input is developed. An optimal control system is designed to improve vehicle response to steering input while minimizing the H2 performance of the body slip angle. The control strategy developed was simulated on a 14 DOF full vehicle model to analyze the response and handling performance.
Technical Paper
2014-04-01
Donald F. Tandy, Steven Beane, Robert Pascarella
Abstract There have been many articles published in the last decade or so concerning the components of an electronic stability control (ESC) system, as well as numerous statistical studies that attempt to predict the effectiveness of such systems relative to crash involvement. The literature however is free from papers that discuss how engineers might develop such systems in order to achieve desired steering, handling, and stability performance. This task is complicated by the fact that stability control systems are very complex and their designs and what they can do have changed considerably over the years. These systems also differ from manufacturer to manufacturer and from vehicle to vehicle in a given maker of automobiles. In terms of ESC hardware, differences can include all the components as well as the addition or absence of roll rate sensors or active steering gears to name a few. Like in the development of passive suspensions and steering systems, a development engineer must take into account the mission of a vehicle.
Technical Paper
2014-04-01
Ibrahim A. Badiru
Abstract The automotive industry commonly uses two definitions of the suspension roll center, the Kinematic Roll Center (KRC) - of interest in studying suspension geometry, and the Force-based Roll Center (FRC) - of interest in studying steady-state vehicle dynamics. This paper introduces a third definition, the Dynamic Roll Axis (DRA) - of interest in studying transient vehicle dynamics. The location of each one of these roll centers has a unique application to vehicle design and development. Although the physical meaning of each roll center is significantly different, the generic term “roll center” is often used without proper specification. This can lead to confusion about how roll centers influence vehicle behavior. This paper hopes to clarify some of this confusion and is organized into three parts: (1) Describes calculation methods for each of the three vehicle roll centers (for independent suspensions) as well as their relevance to vehicle dynamics; (2) Explains the relationship between the kinematic and force-based roll centers; (3) Offers recommendations on considerations for choosing roll center(s) location during vehicle design.
Technical Paper
2014-04-01
Shreesha Y. Rao, JongYun Jeong, Ryan M. Ashby, Gary J. Heydinger, Dennis A. Guenther
Abstract A Software-in-the-Loop (SIL) simulation is presented here wherein control algorithms for the Anti-lock Braking System (ABS) and Roll Stability Control (RSC) system were developed in Simulink. Vehicle dynamics models of a 6×4 cab-over tractor and two trailer combinations were developed in TruckSim and were used for control system design. Model validation was performed by doing various dynamic maneuvers like J-Turn, double lane change, decreasing radius curve, high dynamic steer input and constant radius test with increasing speed and comparing the vehicle responses obtained from TruckSim against field test data. A commercial ESC ECU contains two modules: Roll Stability Control (RSC) and Yaw Stability Control (YSC). In this research, only the RSC has been modeled. The ABS system was developed based on the results obtained from a HIL setup that was developed as a part of this research. The RSC system was developed after a careful study of the field test data obtained from the vehicle manufacturer in which the ESC was activated.
Technical Paper
2014-04-01
Mingyuan Bian, Long Chen, Yugong Luo, Keqiang Li
Abstract A new dynamic tire model for estimating the longitudinal/lateral road-tire friction force was derived in this paper. The model was based on the previous Dugoff tire model, in consideration of its drawback that it does not reflect the actual change trend that the tire friction force decreases with the increment of wheel slip ratio when it enters into the nonlinear region. The Dugoff model was modified by fitting a series of tire force data and compared with the commonly used Magic Formula model. This new dynamic friction model is able to capture accurately the transient behavior of the friction force observed during pure longitudinal wheel slip, lateral sideslip and combined slip situation. Simulation has been done under different situations, while the results validate the accuracy of the new tire friction model in predicting tire/road friction force during transient vehicle motion.
Technical Paper
2014-04-01
Yutong Li, Junzhi Zhang, Chen Lv
Abstract As the main power source of the electric vehicle, the electric motor has outstanding characteristics including rapid response, accurate control and four-quadrant operation. Being introduced into the dynamic chassis control of electrified vehicles, the electric motor torque can be used not only for driving and regenerative braking during normal operating conditions, but also offers a great potential to improve the dynamic control performance of the anti-lock braking under emergency deceleration situations. This paper presents a robust control algorithm for anti-lock braking of a front-wheel-drive electric vehicle equipped with an axle motor. The hydraulic and regenerative braking system of the electric vehicle is modeled as a LPV (linear parameter varying) system. The nonlinearities of the control system are considered as uncertain parameters of a linear fractional transformation. A static-state feedback control algorithm which is robust against the uncertainties is designed to achieve the maximum braking capability of the vehicle.
Technical Paper
2014-04-01
Aref M. A. Soliman, Nouby M. Gazaly, Fatma S. Kadry
Abstract The road condition has an important influence on ride quality; however, the road condition cannot be sufficiently controlled. The proper design of truck components is the only way to improve ride quality. This work is an investigation into the ride behaviour of passive and active suspension systems using full truck model. A mathematical model for the evaluation of ride comfort for a truck moving on an irregular road surface is developed. The cab suspension for passive system is represented by a parallel arrangement of a spring and damper. The gain scheduling (GS) strategy is used to improve truck ride comfort. The influence of suspension elements, tyre stiffness, truck speed and road input on ride comfort is evaluated. The results showed that the active suspension system with gain scheduling strategy gives better ride improvements compared with active system .in terms of vertical cab acceleration. Furthermore, the optimum values of cab spring stiffness and damping coefficient are obtained.
Technical Paper
2014-04-01
Rolf Schneider, Andre Kohn, Karsten Schmidt, Sven Schoenberg, Udo Dannebaum, Jens Harnisch, Qian Zhou
Abstract The infrastructure in modern cars is a heterogeneous and historically grown network of different field buses coupling different electronic control units (ECUs) from different sources. In the past years, the amount of ECUs in the network has rapidly grown due to the mushrooming of new functions which historically were mostly implemented on a one-ECU-per-function basis resulting in up to a hundred ECUs in fully equipped luxury cars. Additionally, new functions like parking assist systems or advanced chassis control functions are getting increasingly complex and require more computing power. These two facts add up to a complex challenge in development. The current trend to host several functions in single ECUs as integration platforms is one attempt to address this challenge. This trend is supported by the increased computing power of current and upcoming multi-core microcontrollers. In this paper, our emphasis is on the practical realization of integration platform ECUs in the chassis domain, which is characterized by higher functional safety, and in the future, high security requirements.
Technical Paper
2014-04-01
Lijiao Yu, Hongyu Zheng, Changfu Zong
Abstract Nowadays, electric control steering system has been a main tendency. It consists of Electric Power Steering (EPS) system, Steer by Wire (SBW) system and Active Front Steering (AFS) system. EPS is more widely applied and its technology is more developed. By 2010, the cars equipped with EPS have reached almost 30%. This paper describes one integrated test bench which can test and verify electric control steering system. The main target of the paper is to design and set up a resistance loading system for the test bench referred. The paper takes EPS as a prototype to verify the designed resistance loading system. If the resistance loading system provides a precise simulated torque for the bench, the results of tests will be more approximate with vehicle tests and the acquired data will be reliable for electric control steering system's design and improvement. The linear electric cylinder applied in the loading system is used to provide simulated torque for the bench. The linear electric cylinder is combined with a kind of software independently designed.
Technical Paper
2014-04-01
Maki Kawakoshi, Takanobu Kaneko, Toru Nameki
Abstract Controllability (C) is the parameter that determines the Automotive Safety Integrity Level (ASIL) of each hazardous event based on an international standard of electrical and/or electronic systems within road vehicles (ISO 26262). C is classified qualitatively in ISO 26262. However, no specific method for classifying C is described. It is useful for C classification to define a specific classification based on objective data. This study assumed that C was classified using the percentage of drivers who could reduce Severity (S) in one or more classes compared with the S class in which the driver did not react to a hazardous event. An experiment simulated a situation with increased risk of collision with a leading vehicle due to insufficient brake force because of brake-assist failure when the experiment vehicle decelerated from 50 km/h on a straight road. First, the relationship between the S class and the difference of speed at the moment of collision obtained in the experiment was classified according to ISO/DIS 26262 Part 3 Annex B.
Technical Paper
2014-04-01
Lijiao Yu, Hongyu Zheng, Changfu Zong
Abstract Nowadays, conventional steering system cannot meet consumers' requirements as their environmental awareness increasing. Electrically controlled steering system can solve this problem well [1] [2]. Electrically controlled steering system has been not only applied widely in automobile steering technique but also becomes an important section of automobile integrated chassis control technology. It is necessary for vehicles to test their every component repeatedly before every component assembled. So a test bench becomes an essential part for vehicle products' design and improvement. The electrically controlled steering system consists of Electric Power Steering system (EPS), Active Front Steering (AFS) and Steer by Wire (SBW). The similarity among them is containing pinion-and-rack mechanical structure, so it is viable to design a test bench suitable for these three systems. This paper takes EPS as a prototype to verify the design's availability. The designed test bench is also used to detect and verify the electrically controlled steering system's performance at the same time.
Technical Paper
2014-04-01
Zhiting Zhu, Lu Xiong, Chi Jin
Abstract The control in transient conditions when hydraulic brake and regenerative brake switch mutually is the key technical issue about electric vehicle hybrid brake system, which has a direct influence on the braking feel of driver and vehicle braking comfort. A coordination control system has been proposed, including brake force distribution correction module and motor force compensation module. Brake force distribution correction module has fixed the distribution results in hydraulic brake force intervention condition, hydraulic brake force evacuation condition and regenerative brake force low speed evacuation condition. Motor compensation module has compensated hydraulic system with motor system, which has fast and accurate response, thus the response of whole hybrid system has been improved. Simulation results in transient conditions show that the coordination control strategy can effectively reduce the fluctuations and deviations of total brake force, and improve braking feel of driver and vehicle braking comfort.
Technical Paper
2014-04-01
Hu Zhang, JianWei Zhang, Konghui Guo
Abstract Whether high-precision torque control or motor condition monitoring need accurate motor parameters. For the three parameters of surface-mounted permanent magnet synchronous motor (SPMSM), the voltage equation is rank-deficient. To solve this problem, some scholars proposed methods that build full rank equations with signal injection, but this will produce motor torque ripple, which is not suitable for application to the EPS. Therefore, this paper proposes a method based on MRAS to identify motor parameters step by step. The proposed two steps identification method can make the reference model full rank in every step, but the total decoupling between parameters identification processes cannot be realized for the assumption that the prior step result is the real value. It was found in experiment that this effect varies with the motor operating conditions. Therefore, this paper analyzes the sensitivity of the motor parameters and proposes a method to improve the accuracy of identification results by changing the weight of identification results according to the operating conditions.
Technical Paper
2014-04-01
Chi Jin, Lu Xiong, Zhuoping Yu, Yuan Feng
Abstract In this paper we present a path following control design for a six-wheel skid-steering vehicle. Contrary to the common approaches that impose non-holonomic constraints, a dynamic vehicle model is established based on a pseudo-static tire model, which uses tire slip to determine tire forces. Our control system admits a modular structure, where a motion controller computes the reference vehicle yaw rate and reference vehicle speed and a dynamics controller tracks these signals. A robust nonlinear control law is designed to track the reference wheel speeds determined by the dynamics controller with proved stability properties. Saturated control techniques are employed in designing the reference yaw rate, which ensures the magnitude of the reference yaw rate does not violate the constraint from the ground-tire adhesion. The simulation results demonstrate the effectiveness of the proposed path following control design.
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