Transcript
Measurement & instrumentation
Rear obstacle detection systems: a boon for vehicle safety by Neelu Singh, Frost & Sullivan
Automotive safety is a big concern for consumers around the world and car manufacturers are constantly looking for innovative ways to improve their vehicles. Automotive rear obstacle detection systems offer one way of decreasing the risk of accidents by using radar and image sensors to monitor the proximity of objects to the car.
The technology A rear obstacle detection system monitors a range of 3 to 6 m behind the vehicle and sends a warning signal to the driver when the vehicle is approaching an object in reverse. The technology recognises targets by means of radar or sonar. The system sends an advance audible and/or visual distance-based alert to the driver, helping to avoid collisions with objects behind the vehicle. The sonar (sound navigation and ranging) technology detects obstacles by emitting a transmitter pulse of ultrasonic energy. A receiver fitted in the vehicle then perceives the resultant echo reflected by the detected object. When the inaudible sound wave sent by the emitter encounters an object, it is reflected back to the receiver circuit, which is tuned to the frequency of the emitter. The receiver then transforms the pulse and sends data to a driver display unit. Radar (radio detection and ranging) technology determines the range of objects by transmitting ultra high frequency radio waves. These radio waves are transmitted from the vehicle at defined intervals within a specified coverage area. The electromagnetic waves reflected by an object behind the vehicle are then collected by the sensors and are sent to a signal-processing unit and communicated to a driver interface. Application and benefits of radar and sonar technologies • The benefits of rear obstacle detection systems are that it: • Acts as a safety measure in reversing and parking • Provides an advanced warning about obstacles in low-visibility situations like rain, snow, and fog • Is useful in avoiding blind spot-linked vehicle accidents • Assists drivers reversing vehicles into unfamiliar docks and tight parking spaces • Reduces injuries, repair costs, and vehicle downtime by avoiding collisions related to backing up 68
Obstacle detection systems are intended to increase driver alertness and therefore require the driver’s attention and appropriate response to avoid accidents. Rear obstacle detection systems are installed as original equipment in some high-end vehicles, but they can also be purchased as an aftermarket item. They are either sensor-based (ultrasonic or radar) or visual-only systems.
The system sends an advance audible and/or visual distance-based alert to the driver Delphi dual-beam radar back-up aid Delphi provides a 24 GHz dual-beam radar backup aid to detect obstacles behind the vehicle and assist in parking. This new technology uses a speed-sensitive algorithm and adaptive audible and (optional) visual alerts to send advance warnings to help the driver avoid accidents. The system also provides distance-based alerts to make parking easier, and is suitable for light, medium, and heavy-duty vehicles. The system detects moving and non-moving objects in a 5 m sensor range. It also offers the longest detection zone, giving the driver more time to react to detected obstacles. The back-up aid operates under a wide range of environmental conditions, including rain, snow, ice, fog, and noise, in daylight and in darkness. Unlike camera-based systems, it does not require the driver to monitor a visual display. It features a CAN-based interface to enhance collision mitigation countermeasures. The Ford Explorer SUV uses this technology, featuring a detection range of 5 m behind the vehicle. Siemens blind-spot detection system Siemens blind-spot detection and lane change assist systems use radar sensors and are designed to provide driver assistance by expanding the rear view angle. The system
provides early visual warnings in case an object is in a blind spot. The system expands the driver’s limited viewing angle and helps in heavy traffic areas, parking, and changing lanes. If a car is in a blind spot, the blind spot detection warning starts at 10 km/h. At 60 km/h, the lane change assist function is activated additionally. The company also offers Park Mate, an advanced driver assistance system to facilitate parking. The blind spot detection system will feature in the 2008 BMW 5-series. LS 460 featuring rear pre-crash safety system Lexus, the luxury vehicle division of Japanese automaker Toyota, offers the rear pre-crash safety system in its LS 460 vehicle. The system uses millimeter-wave radar set into the rear bumper and stereo cameras to constantly scan the area around the back of the car, both when it is moving and when it is parked. The LS 460 also provides emergency steering assist aids in substantially improving the vehicle’s response to the driver’s steering input in the likelihood of a collision, increasing the chances of avoiding the obstacle. In the event of a collision, the pre-collision seatbelt retracting mechanism activates and the brakes are applied automatically to help reduce the consequences of the impact. Lexus plans to be able to offer a complete advanced pre-collision system package, consisting of advanced obstacle detection, emergency steering assist, lane-keeping assist, and driver monitoring systems to avoid collisions. TRW’s collision warning system The collision warning system from TRW helps to prevent or mitigate collisions by monitoring the road through short- and long-range radars, along with a video camera. The system sends advance audio/visual alerts for an approaching obstacle, and also activates emergency brake assistance to provide full brake force. Using a digital signal chip, the processor performs target identification and tracking computations needed to make sense of the signals from the radar sensor. Nov/Dec 2007 - EngineerIT
Eagle eye electronic obstacle detection system The Eagle Eye Electronic Obstacle Detection System uses ultrasonic technology to provide driver assistance through a single driver alert module. It is mainly targeted at the heavy truck segment. It consists of up to seven sensors and has a 3 m detection zone. The system warns drivers of obstacles when reversing or changing lanes. The company offers this rear-obstacle
detection system as an aftermarket product, which works well for both heavy trucks and tractor-trailer combinations. Conclusion Frost & Sullivan expects radar sensor technology to experience strong growth in the short to medium term due to its persuasive technological advantages, better adaptability to harsh environmental conditions, and cost-effective solutions. Safety concerns and market interest
could bode well for tier-one system developers such as Delphi Corporation, Siemens VDO, Robert Bosch Corporation, Continental AG, Hella Valeo, and TRW Automotive Holdings. Furthermore, integrated safety systems like radar-based adaptive cruise control and automatic collision mitigation systems are set to take automotive safety to the next level. Contact Patrick Cairns, Frost & Sullivan, Tel 021 680-3274,
[email protected]
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