Editorial Feature

Vehicle Crash Sensors: Obstacle Detector

A blind spot is a location that is invisible to the driver from the driving seat or with the use of the three mirrors. This spot is found at the vehicle sides or directly behind the vehicle.

Vans, SUVs, trucks, and higher vehicles tend to have larger blind spots. Blindspot causes numerous accidents, resulting in fatalities, injuries, and property damage.

An obstacle detection sensor, also known as parking systems, detects an obstacle in the blind spot and warns the driver before an accident occurs.

This system operates by receiving or sending out high-frequency sound waves. A microprocessor within a control module of the sensor registers sound waves that bounce off the surface of the obstacle. The sensor measures the type and length of the waves to interpret the size and distance of the obstacle.

Large objects usually emit different sizes of energy wavelengths and reflect a totally different carrier wave signature. Obstacle detection helps in identifying the hidden dangers of the blind spots.

Types of Obstacle Detection Systems

Obstacle detection systems usually fall into the following categories:

Electromagnetic Sensors

These sensors can be used in vehicles moving slowly and smoothly towards the obstacles. If the vehicle stops immediately upon the detection of an obstacle, the sensors continue to emit a signal of obstacle's present.

If the vehicle resumes its movement, the alarm signal becomes more prominent as the obstacle approaches. These sensors are commonly used as they do not require drilling of holes in the vehicle and they can be discreetly mounted on the inner side of the bumper.

Wireless Ultrasonic Sensors

These sensors are highly sophisticated devices that create sharp radio signals for detecting the obstacles. They use the echo time of the radio signals bouncing from the obstacles to indicate the distance of the obstacle. Wireless ultrasonic sensors range from four to eight, placed equally in the front and rear parts of a vehicle. They detect objects even when the car is stationary.

Reverse Car Parking Sensors

These sensors are commonly used during parking the car in a reverse car parking system. They get activated as soon as the car is put in reverse gear, and are usually placed in the front side of a vehicle. Reverse car parking sensors are small in size and generate ultrasonic radio waves to send and receive signals reflected from the obstacle. Mazda has already integrated this technology into their vehicles as is demonstrated in the video below:.

How Obstacle Detection Systems Work?

An obstacle detection system employs ultrasonic proximity sensors that are mounted in the front and/or rear bumpers to evaluate the distance between the vehicle and nearby objects at a low level. These sensors also measure the time taken for each sound wave to be reflected back to the receiver.

Based on the vehicle speed and obstacle distance, the system will warn the driver about the collision risk through audio/visual means. The feedback given to the driver will indicate the proximity and direction of the obstacle.

Audible beeps or tones are the most common forms of a feedback system. The frequency of the tone represents the distance from the obstacle, with the tones becoming faster as the vehicle comes closer to the object. When a vehicle is very close to the object, the sensors emit a continuous tone, as a warning to make the driver stop immediately to avoid a collision.

Certain systems employ visual aids such as LCD or LED readouts to indicate the object distance. The distance and direction of the object are represented by the strength and location of the warning symbols. Several cars also include an infotainment screen in which a pictogram of the vehicle is displayed with a visual representation of the objects indicated as colored blocks.

Advantages of Obstacle Detection Systems

Some of the key benefits of obstacle detection systems include the following:

  • To help drivers reversing vehicles into tight parking spaces and unfamiliar docks
  • Such systems minimize repair costs, vehicle downtime, and injuries by avoiding collisions.
  • This technology is easy to install
  • Acting as an advanced warning about obstacles under low-visibility conditions like fog, snow, and rain.

Products – Latest Advancements

Obstacle Detection Sensor (ODS)

ODS developed by Cooper-Standard Automotive work by controlling reverse door closures and power windows when objects pass through its sensing field to reduce non-crash related occupant injuries.

This system features a proximity obstacle detection sensor (P- ODS) that works by transmitting a power window/door reversal signals when an object comes within 3 mm of the extruded sensor during the closure. It also includes a tactile obstacle detection sensor (T-ODS) to initiate a signal when an object obstructs the window/door during the closure.

SS-4000W- Sidescan Sensor System

Brigade's high-quality side sensor system consists of underslung sensors with a 1 or 1.5 m detection range and waterproof control box. It is ideal as low-speed maneuvering helps on the near side of the vehicle. It has audible distance warning and two levels of sensitivity.

The key benefits of SS-4000W- sidescan sensor system includes the following:

  • It detects obstacles within 200 ms
  • It has a self-diagnostic function
  • It includes environment learning mode which prevents false alarms.

Sources and Further Reading

  • SS-4000W- Sidescan sensor system - Brigade
  • Obstacle Detection Sensors - Cooper-Standard Automotive
  • Obstacle Detection – Ackton Transport Technologies
  • Parking sensors – Which?

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