Paper Control Longitudinal De Vehiculos
Páginas: 7 (1606 palabras)
Publicado: 7 de julio de 2011
Driver AssistAnce systems
An introduction to Adaptive Cruise Control (ACC)
By Rainer Troppmann Texas Instruments Inc. and Andreas Höger Robert Bosch GmbH
The surround sensing problem Almost continuously, someone in the world dies from a traffic accident; countless more suffer injuries. Moreover, the economic losses caused by traffic accidents are reaching astronomical proportions. Vehiclemanufacturers and their suppliers have made it their goal to avoid such accidents, or at least to mitigate their effects. Much automotive safety improvement can be made thanks to automotive electronics developments. Analyses of the correlations between collisions and driver reactions have shown that a considerable number of accidents can be avoided by recognizing a hazard in sufficient time andmaking appropriate driving maneuvers. Such actions can be achieved by warning signals to the driver or by automatic longitudinal and lateral control of the vehicle (Driver Assist Systems). Suitable sensors are a requirement if the hazardous situation is to be identified. A resulting sensor network covers the area around the vehicle in conjunction with a suitable human-machine interface. Electronicsurround sensing systems form the basis of numerous Driver Assistance Systems—systems for warning or active intervention. One area of these Driver Assistance Systems is aimed at avoiding frontal collisions, which can be significantly reduced by accident warning systems and active braking intervention. Adaptive Cruise Control (ACC) is the first step in this direction. Today’s ACC systems are mainlybased on radar systems
in the millimeter wave range. Millimeter wave radar systems are divided into pulsed and continuous wave systems, which are in turn subdivided into frequency modulated continuous wave (FMCW) and spread spectrum systems. 77 GHz FMCW radar systems allow objects to be detected within a range of 1 to 150m. At the same time, their distance and speed relative to the hostvehicle—and with the right number of antennas, also their angle to the longitudinal axis of the vehicle—are determined. Surround sensing systems— Adaptive Cruise Control Surround sensing systems (see figure below) forming the basis of numerous Driver Assistance Systems are differentiated into: • Ultrasonic-, radar-, video- and navigation-based systems • Passive and active systems • Safety and conveniencesystems • Driver support, passive safety, collision mitigation, and vehicle control systems, according to their function within the system Adaptive Cruise Control systems fall within the functional area of vehicle control and actively intervene in the longitudinal control of the vehicle. They decelerate the vehicle if it gets closer than a set minimum distance from the preceding vehicle andaccelerate it to the set speed if there is a sufficiently large gap. ACC systems are currently installed as convenience systems. Their braking intervention is limited to a maximum of 30% of braking force capability; the driver is in ultimate control of the vehicle. Current ACC systems are therefore particularly suitable for roads with less traffic density, such as Interstates or
Figure 1
Figure 2Figure 3
highways. With additional sensors, future ACC systems will be suitable for driving in heavy traffic in urban areas. Further developments of ACC Stop-and-Roll (S&R) and ACC Stop-and-Go (S&G) are intended to allow automatic stopping and starting in order to make lanes safer and improve traffic flow. The ultimate aim of
these Driver Assistance Systems is 360-degree coverage of thearea around the vehicle; in the area of vehicle control, the goal is to expand the ACC function to achieve complete longitudinal control. Sensors for surround sensing Covering the entire area around the vehicle requires a series of
EE Times-India | eetindia.com
Figure 4
Figure 5
Figure 6
Figure 7
different sensors (see above). Two types of sensor, infrared (IR) sensors and...
An introduction to Adaptive Cruise Control (ACC)
By Rainer Troppmann Texas Instruments Inc. and Andreas Höger Robert Bosch GmbH
The surround sensing problem Almost continuously, someone in the world dies from a traffic accident; countless more suffer injuries. Moreover, the economic losses caused by traffic accidents are reaching astronomical proportions. Vehiclemanufacturers and their suppliers have made it their goal to avoid such accidents, or at least to mitigate their effects. Much automotive safety improvement can be made thanks to automotive electronics developments. Analyses of the correlations between collisions and driver reactions have shown that a considerable number of accidents can be avoided by recognizing a hazard in sufficient time andmaking appropriate driving maneuvers. Such actions can be achieved by warning signals to the driver or by automatic longitudinal and lateral control of the vehicle (Driver Assist Systems). Suitable sensors are a requirement if the hazardous situation is to be identified. A resulting sensor network covers the area around the vehicle in conjunction with a suitable human-machine interface. Electronicsurround sensing systems form the basis of numerous Driver Assistance Systems—systems for warning or active intervention. One area of these Driver Assistance Systems is aimed at avoiding frontal collisions, which can be significantly reduced by accident warning systems and active braking intervention. Adaptive Cruise Control (ACC) is the first step in this direction. Today’s ACC systems are mainlybased on radar systems
in the millimeter wave range. Millimeter wave radar systems are divided into pulsed and continuous wave systems, which are in turn subdivided into frequency modulated continuous wave (FMCW) and spread spectrum systems. 77 GHz FMCW radar systems allow objects to be detected within a range of 1 to 150m. At the same time, their distance and speed relative to the hostvehicle—and with the right number of antennas, also their angle to the longitudinal axis of the vehicle—are determined. Surround sensing systems— Adaptive Cruise Control Surround sensing systems (see figure below) forming the basis of numerous Driver Assistance Systems are differentiated into: • Ultrasonic-, radar-, video- and navigation-based systems • Passive and active systems • Safety and conveniencesystems • Driver support, passive safety, collision mitigation, and vehicle control systems, according to their function within the system Adaptive Cruise Control systems fall within the functional area of vehicle control and actively intervene in the longitudinal control of the vehicle. They decelerate the vehicle if it gets closer than a set minimum distance from the preceding vehicle andaccelerate it to the set speed if there is a sufficiently large gap. ACC systems are currently installed as convenience systems. Their braking intervention is limited to a maximum of 30% of braking force capability; the driver is in ultimate control of the vehicle. Current ACC systems are therefore particularly suitable for roads with less traffic density, such as Interstates or
Figure 1
Figure 2Figure 3
highways. With additional sensors, future ACC systems will be suitable for driving in heavy traffic in urban areas. Further developments of ACC Stop-and-Roll (S&R) and ACC Stop-and-Go (S&G) are intended to allow automatic stopping and starting in order to make lanes safer and improve traffic flow. The ultimate aim of
these Driver Assistance Systems is 360-degree coverage of thearea around the vehicle; in the area of vehicle control, the goal is to expand the ACC function to achieve complete longitudinal control. Sensors for surround sensing Covering the entire area around the vehicle requires a series of
EE Times-India | eetindia.com
Figure 4
Figure 5
Figure 6
Figure 7
different sensors (see above). Two types of sensor, infrared (IR) sensors and...
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