3D sensors: Safe manoeuvring instead of colliding

Picture the scene: it’s a busy global port and a driver is looking straight ahead while moving containers 14 metres wide and up to 40 tonnes in weight, through narrow stacks. Even when manoeuvring in reverse the driver must keep an eye on the transverse container to avoid hitting the rows of containers stacked on top of each other like a wall.

To avoid collision within the container terminals during narrow and rapid manoeuvring, ifm electronic offers a solution: a small 3D camera monitors the rear area, detecting objects in the travel path and warns the driver of possible collision.

This automatic collision technology is useful for a variety of applications. When two reach stackers move towards each other while being manoeuvred in reverse; when trucks cross the way; or when objects or people are in the manoeuvring range.

ifm’s O3M camera provides active protection: its integrated 3D sensor not only displays obstacles behind the vehicle on a screen in the cockpit but also determines the obstacle’s size, position and movement, if any, warning the driver of anything in the path or on a collision course.

The principle of these 3D sensors is based on ifm’s patented and award-winning PMD technology which is using ToF (Time of Flight) principles,” explained Dan Buzatu, ifm product manager. “This technology enables fast and efficient 3D imaging by delivering 2D and 3D information at the same time for each pixel, unlike laser scanners, which possess the negative characteristic of motion blur.”

 Another advantage of the intelligent O3M system is that if a vehicle moves into the travel path from the side the risk is detected much faster than with a distance-based warning.

By integrating a conventional 2D camera with the pixel-accurate, distance measuring 3D camera, detected objects can be highlighted in colour in the produced 2D image. Critical obstacles can be highlighted in red (with additional warning system), with less critical objects in yellow or green.

Buzatu said that machine operators referred to ifm’s sensor as a “third eye that does not sleep or suffer from fatigue” and a “trustful assistant”.

“It was specifically designed for outdoor use and difficult ambient light situations,” he added. “Even interference such as sunlight or materials with different reflective characteristics do not influence the repeatability of the measured data.”

This overlay is completely generated in the O3M – additional hardware and complex set-up is not needed. Visualisation options – such as colours, symbols and language – can be easily and conveniently adapted to the application conditions with the ifm Vision Assistant for Windows.

The mobile 3D smart sensors feature integrated evaluation functions which, besides the collision avoidance described here, enable a multitude of other applications to be solved, e.g. line guidance or area monitoring. A highly developed automotive industry algorithm is used, ensuring automatic recognition of up to 20 objects.

In just a few steps the system is set. To do so the user only needs to enter some parameters, such as the vehicle’s geometry. Usually this set-up only takes a couple of minutes and the system is then ready for operation.

Path monitoring and distance monitoring are also available to users; the former allows for a freely adjustable monitoring point on the vehicle that allows only obstacles of a predefined height above ground to actually be detected as such; the latter applies to simple distance functions, with integrated distance monitoring provides up to 64 adjustable regions of interest.

This reaction can be graded depending on the distance to the obstacle, i.e. at first an acoustic and visual warning is given. If the driver does not react and the situation becomes more critical, the vehicle can brake gently.

For mining applications, the sensor is particularly useful for under- and above-ground drill rigs, collision awareness on dump trucks, among various other machines. Just about anywhere that requires slowing down or stopping a machine operation in the event of a safety breach can take advantage of ifm’s collision awareness technology in this regard.

“Solid state componentry make the sensor perfectly suited for mobile machinery, where high shock and vibration is present,” explained Buzatu.