1,721,386 research outputs found
Efficient Control-Oriented Coupled Electrochemical Thermal Modeling of Li-Ion Cells
Full text linkSafe and effective exploitation of lithium ion (Li-ion) batteries requires advanced battery management systems. This article proposes a computationally efficient, control-oriented model of a Li-ion cell. The model describes the spatial nature of both the chemical species and temperature dynamics in a computationally efficient way. The method takes advantage of the algebraic structure that arises from the distributed nature of the model. We show that, by discretizing the model partial differential equations with a finite difference method, the coupling equations take a semiseparable structure for which an efficient algebra exists. This approach yields an efficient modeling tool that can be employed to design model-based estimation and control algorithms. The proposed model is validated against a high order computational fluid dynamics model showing accuracy and efficiency
Design, Analysis, and Validation of a Haptic-Based Driver Support System for Traction Control
No full textThis paper presents the design of a driver support system for the manual acceleration control of a car. The aim of the system is that of assisting the driver safely accelerating on a slippery surface. A force feedback (haptic) gas pedal guides the driver toward applying the correct throttle; the haptic-based approach enables the driver to override the system if needed. The following three main issues are addressed: 1) the choice of the feedback law; 2) the stability of the haptic interaction at the neuromusculoskeletal level, formally analyzed through the passivity framework; and 3) the tuning and the validation of the system. An experimental campaign, carried out with a driver-in-the-loop simulator in two driving scenarios, shows that the system improves safety without negatively affecting performance. The occurrences of the loss of control are reduced from 35% without haptic feedback to 10% with haptic feedback. The subjective feedback from the test drivers is also analyzed, showing acceptance
A Haptic-based Traction Control System
No full textThis paper presents a haptic support system for
traction control (HTC). The haptic gas pedal exerts a wheel
slip dependent force; this enables an efficient information
transfer so that the driver is able to close the loop. The
paper presents the basic rationale and validates it with an
experimental campaign carried out with a driver-in-the-loop
simulator. Two challenging driving scenarios are explored with
numerous test subjects. The system improves safety without
negatively affecting performance. The occurrences of loss of
control are reduced from 35% without HTC to 10% with HTC.
The subjective feedback from the test drivers is also analyzed,
showing a good level of acceptance
Mixed Kinematics and Camera Based Vehicle Dynamic Sideslip Estimation for an RC Scaled Model
No full textVehicle side slip angle is at the basis of many vehicle dynamics control systems. Many methods are available to estimate side-slip angle using on board sensors (usually accelerometers and gyros). The technical advances pertaining autonomous vehicles made an additional kind of sensor available: cameras. This study develops a mixed kinematic vision-based side slip angle estimation. The proposed algorithm merges the information of a commercial grade inertial measurement system, wheel encoders and information from a camera. The camera measurement are integrated in a Kalman filter observer. The paper implements and tests the approach on an instrumented RC scale vehicle, comparing the proposed approach against a kinematic based estimation. Experimental results show a decrease of a factor between 2 and 10 (depending on the type of maneuver) of the estimation mean squared error
Haptic Playback: Modeling, Controller Design, and Stability Analysis
No full textWith new surgical tools and techniques being continuously
introduced, efficient teaching of sensorimotor skills has
become an important issue in surgical training. Sensorimotor
skills are traditionally taught by a trainer who physically
interacts with the trainee. This method is expensive and time
consuming. Haptic playback represents an efficient solution to
this problem allowing to simultaneously display position and
force information to users. The traditional framework used in
haptics does not well adapt to this task. This paper proposes
a new framework that allows to formally address the issues
deriving from simultaneously displaying force and position. This
is achieved with the introduction of an information channel and
the modeling of the operator as a MISO system. An intuitive and
simple model for the user is proposed and validated through
experiments with human subjects. The model is then used to
design a control strategy, the crossed controller, that exploits
both the haptic channel and the information one. The stability
of the controlled system can be studied with formal methods.
The performance of the crossed controller is finally tested against
a more traditional controller through experiments with human
subjects
Experimental Identification of Engine-to-Slip Dynamics for Traction Control Applications in a Sport Motorbike
No full textDesign and Control of an All-in-the-Wheel Assisted Kick Scooter
No full textTraffic congestion, energy efficiency, and environmental issues are fueling the interest in light electric vehicles. In particular, electric human-powered hybrid vehicles are compelling because of their low cost, ease of use, lightweight, and extremely small footprint. This paper presents an electrically assisted kick scooter. Most electric scooters are throttle-controlled; this makes them electric vehicles, and as such, they may require driving licenses. The proposed design solves this limitation by introducing the electrically assisted kick scooter concept. The proposed design does not have any human-machine interface device. It controls the electric assistance in a transparent way. The user operates the vehicle as a passive scooter, while the control system smoothly delivers the assistance. The proposed solution is based on several functional modules: a kick detection algorithm, a closed-loop control of the vehicle velocity, a brake detection algorithm, and an online parameter estimator that makes sure that the vehicle behaves consistently no matter the road surface. The details of the control system are discussed in the paper, and an extensive experimental validation based on metabolic and electric measurements shows that the electric assistance cuts in half the effort necessary to operate the vehicle with an average battery consumption of 4 Wh/km
AUTOMATIC CONTROL METHOD AND SYSTEM FOR THE VIRTUAL CONFINEMENT OF A LAND VEHICLE WITHIN A TRACK
No full textThe present invention concerns a method (900; 1000) of automatic confinement of a land vehicle. In the embodiments of the present invention, the method (900; 1000) provides that the control unit (30) performs the following steps. Defining (900) a set of points of a track within which the vehicle is free to move, said track including at least one edge that defines a boundary of the track that must not be crossed by the vehicle. Determine (1001) a vehicle dynamic and position based on the information provided by plurality of sensors of the vehicle. Calculating (1005) an intervention area of the track based on the current position and dynamic of the vehicle, and on the position from the at least one edge, the area to be avoided extending between the at least one edge of the track toward the current position of the vehicle within the track. Determining (1007) whether the vehicle is at least partially in the intervention area. In affirmative case, controlling (1013) at least one actuator to modify the vehicle dynamic to perform an exit maneuver that brings the vehicle outside said intervention area. In particular, calculating (1005) an intervention area comprises performing the following steps. Calculating (10055) a first collision area based on the current position and dynamic of the vehicle, the position from the at least one edge and an ability to modify the vehicle dynamic of the driver by acting on said at least one actuator. Calculating (10057) a second collision area based on the current position and dynamic of the vehicle, the position from the at least one edge and an ability to modify the vehicle dynamic of the control unit by acting on said at least one actuator. The first collision area and the second collision area correspond to regions of the track within which reaching and/or crossing said at least one edge is inevitable when the vehicle moving according to the current dynamic is driven by the driver or by the control unit, respectively. Finally, defining (10058) the intervention area as the area resulting from the difference between the first collision area and the second collision area
Road Slope Estimation in Bicycles without Torque Measurements
No full textElectrically Power Assisted Cycles (EPACs) have been gaining increasing attention worldwide during the past few years. The delivery of a good assistance during inclines makes or destroys an EPAC. This paper addresses the low-cost estimation of road slope on bicycle without pedaling torque measurement. Two estimation algorithms are discussed. A full 6 Degrees of Freedom kinematic Extended Kalman Filter and a simpler, more cost-effective 2 DoF Kalman filter based on the longitudinal kinematic model. The proposed reduced-sensor algorithm is shown to be very accurate during straight running; however it is affected by errors during cornering. This issue is addressed by augmenting the filter with a curve correction algorithm. The curve correction algorithm, based on a time-varying low pass filter is detailed and validated on experimental data, comparing the estimated road slope against cartographic data
Longitudinal Velocity Estimation in Single-Track Vehicles
No full textVehicle dynamics control systems are becoming available for single-track vehicles. The dynamics of single-track vehicles have some unique features that require ad hoc solutions. One of the most critical aspects is the estimation of the vehicle body velocity. In this paper the problem of estimating the body velocity of a two wheeled vehicle for traction control applications is discussed. The front wheel velocity and the longitudinal acceleration measurements are used to estimate the vehicle velocity according to a sensor fusion philosophy. The complementary filter approach is compared against a more advanced Kalman filter. It is shown that the mentioned Kalman filter can be written as a second order complementary filter; this allows to derive quantitative guidelines for the tuning of the filter. The proposed methods are shown to be more robust to wheelies than the front wheel velocity based estimate. Experimental tests on an instrumented bike validate the methods for traction control applications
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