Wide angle laser beams for anti-collision

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Wide angle laser beams can detect and measure the range to people, trees and other safety critical objects from moving aerial or ground based platforms.

We've been experimenting with a new version of our SF10 laser altimeter to see what happens when we change the normally narrow, parallel laser beam into a wider, fan shape and align it horizontally or with a downwards tilt. There is a practical limit to the wide direction (major axis) of about 30 degrees but any angle from zero to thirty degrees is attainable. The best combination of range and sensitivity is found using a 10 x 3 degree beam pattern that can detect a person more than 10m away.

The two pictures above show the SF10 laser unit and an example of the modified laser beam pattern. The intensity, and therefore the detection sensitivity, is pretty uniform across the beam so even obstacles right at the edges give a good return signal. We're using time-of-flight technology to work out the distance and the unit has I2C, serial and analog interfaces.

The real purpose of this blog post is to ask the knowledgeable members of this forum for feedback about possible applications for wide laser beams, used either stand alone or in multiples. I admit that this is not going to be the ideal solution to every problem. Instead, I hope to use your feedback as a sanity check to see if we're going in the right direction with this technology.

Thanks, LD

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  • we would use the wide beam SF10 on our forwards mountings in our warehouse. currently using SF10 for vertical, and cheap IR/sonar for forward sensing, but need to maintain distance of 1m in front of warehouse racking, so need a wider beam, the narrow laser beam of the sf10 will shoot through the gap between the pallets and the shelf.

    we would need a wide beam facing forwards . if it could sense upwards, we could also possibly use it  to prevent the drone flying forwards into void spaces  ("overhangs") where there are no pallets. more info on www.dronescan.co

    DroneScan
    DroneScan has developed an airborne data collection system to provide large, uniform warehouses with a robotic solution for stock take (inventory), p…
  • There is a demand for affordable airborne lidars, as I said - as part of creating computerized awareness of the space for the uav: there is lidar and there is comp. visionary , they both being used in researches .
    Most of  wealthy companies today will use Velodyne lidar for R&D but its not  suitable for mass use.

    Velodyne lidar: Vehicles : OshKosh, Lexus, Audi, BMW, Google, Nokia, Telemap(none of them have commercial solution because of the expensive sensors).
    lidar in air vehicles: used in geo mapping, agro mapping, mining operations,military demands , autonomous flight and collision avoidance procedures, and so more.

    I assume at first enthusiasts and researchers will purchase it, that`s why it will be smart to sell it in some kind of developer package.

    Developing this  line of of products in future closely with researchers/designers means they may use your product in their production process. So it has a good potential even if you cant see the benefit of it now.

  • I would buy it!  I'm of the understanding that the higher data rates are useful to reduce the angle swept where no detections are made for a given RPM?

    I think that I'd like to have the ability of streaming 10k readings per second, but that's got to be tempered by the ability to measure the beam source origin and angle so that the position of the reading in 3D space can be accurately calculated.

    I think it's relatively easy to reject close duplicates so that any visualisations or processes using all stored points can be done with the smallest data set possible - further simplified by rules which allow the use of simpler geometry.

    Obviously the accuracy of the base data is the foundations on which a good system is built.

  • Thanks @Phill and @Eli for the comments. It always astonishes me when people ask for hardware that they can't actually use, but perhaps this is a case of driving the technology in the right direction and letting the supporting architecture take care of itself.

    I think we could produce a good quality 2D laser scanner that retails for less than $1k. What I don't understand yet, is why would anyone buy it?

  • 10 k of readings/sec for a single laser is indeed a lot of data, too much.
    You should process significantly less data , try to reduce data signals frequency before they reach processing area such as MCU(if you have one on device) or flight controller.
    Also guys who will use such device will know they will need to adjust the computing power of the flight controller accordingly.
    for future - Its best if the user(AI software) could choose its own preferable data rate/data reading frequency, so it could adjust accuracy according to real time events by demand.

    By designing such device you will supply a growing demand for scanners such as Lidar. Lidars are too expensive even for research, and I didn't noticed any other competitor in this field - so if you ask me such hardware(2d/3d) will draw great interest.

  • I don't believe that you could do that sort of processing on any current flight controller.  It would have to be offloaded to a single board computer, and the only one I can think of would be the Jetson because of its CUDA capability.  At least that's my plan...

  • Thanks for the comment Eli. Any ideas how you would process more complex data on the fly? We have tested out a 2D rotary unit that can measure out beyond 100m at >10,000 readings per second. That's a lot of data for a small flight controller to digest.

  • Hi, look`s nice and elegant.
    The next comment is for a case you intend to commercialize the idea/device:

    I think that today - creating computerized awareness of the space for the uav - is critical for future development of an autonomous mission management. 1d measurement device could not contribute enough for the system which has to take real time decisions and maneuvering.
    Using it could help in ground maneuvering or in pre-landing procedures, but beside that, it will be useless.

    UAV designers tend not to add objects which will not be relevant while UAV in air.

    In my opinion, creating an additional product with rotary base(encoded motors), so the product could output 2d or 3d scans - would make it a lot useful for the developer/designer.

  • @Alex can you describe your sonar setup and experiences. I would like to hear more especially about interference when using multiple sensors.

  • Taking this biological analogy one step further, autonomous systems such as drones could be designed more on a Maslow architecture, where the final mission is actually the least "necessary" component of the design and instead represents the final stage of actualization. This way more emphasis is made of basic survival characteristics such as not flying or running into things.

    We could create capability or activity diagrams that show which features are truly critical to survival, and work up the pyramid to those that have commercial or entertainment value. For example, this approach would turn the whole "conflict" with the FAA on its head because the first requirement for survival would be "Don't hurt people". Failure to deal with this fundamental problem could lead to extinction on many levels!

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