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10

This is a common problem, and one of a great many. Acoustic sensing is a complicated field of study, a significant part of which is spent guessing what path a sound wave took between sending it and receiving it. As you've noticed, assuming that it went straight out and came straight back will produce odd results in practice. To really solve it, you'll ...


7

The sound beam is not traveling in a straight line but is leaving the range finder is a multi-lobed pattern. Of course we are interested in the main lobe. When the sound wave hits an object, it is reflected in various directions. So some of that energy returns to the sensor and triggers it, therefore measuring the distance. Reflection depends on the ...


5

Some sensors, such as the Maxbotix MB1200 XL-MaxSonar-EZ0, have a daisy chaining system built in where one sensor triggers the next sensor once it has finished its measurement. This way you can have N sensors and ensure that only one is firing at once but that there the next sensor fires as soon as the first has collected its return. This solution is simple ...


4

Is it possible to use multiple ultrasonic sensors on a single robot? Yes: "Using Multiple Sonar Sensors". As you have already figured out, one sensor often receives echoes of pings sent by another sensor. There are several ways to deal with cross-sensitivity, roughly in order of simplest first: Ping only one transducer at a time, ignoring all the other ...


3

This representative sample of what's out there may give you some idea of what's out there at various price points: Unfortunately, you're talking several thousand dollars for an outdoor unit with 10's to 100's of meter range (as of March 2015). The chart is from a blog article I wrote on the topic. Google used a $70-80K unit on their original vehicles. The ...


3

As you've noted, a pool is one of the worst environments in which to test acoustic sensors; there is nothing to dampen the echoes, and the multipath is quite extreme. Generally, one of 3 things is done to help mitigate these effects -- the goal being an anechoic test chamber. Make the shape of your test tank such that all echoes are reflected into a trap....


2

Setting up the software to extract new custom sensor data via MAVLink seems to be harder than it should be. Step one is to make the quadcopter send off the data. First, you need to define a new MAVLink message type using XML in mavlink/message_definitions. You can just make up a new unused integer for the message_id. Second, you generate the message ...


2

I just answered the question on StackOverflow, where it already been asked. Here is the link: https://stackoverflow.com/questions/21249131/monte-carlo-localization-for-mobile-robot


2

Your cheapest option will probably be to use a ultrasonic sensor on a stepper, by advancing the server one step and reading the distance. The only downside to this will be the resolution you can get, which will be depend on your ultrasonic sensor. Another thing to consider is that ultrasonic waves don't work well on curved surfaces so the accuracy could ...


2

I don't have enough reputation to comment, but I'll add my 2cents in an answer. Basically you're limited to lidar mapping if you want any decent fidelity. Stereoscopic imaging via OpenCV in one distribution or another will be processing intensive and will take too long for any type of real-time navigation unless you're just shredding things computationally ...


2

Sonar, as used in robotics means having an ultrasonic emitter and and ultrasonic receiver. There are also some sonar with a single emitter/receiver. However, they all use ultrasonic sound ways in order to sense the distance to an object. Well, actually they really sense the time between the emission of the ultrasonic wave and the reception of it, which is ...


2

Currently I am performing my research on that, and in my case I decided to tune all the PIDs. Angles of the quadrotor tend to zero, while altitude controller tend to the objective height. That's habitual in bibliography. In my particular simulations on the computer, PD parameters were enough and all the controllers adapted the same Proportional and ...


2

Another sensor that you should investigate is ultra-short baseline (USBL). I have used the MicronNav with success in the past. You mentioned accelerometers, but what I think you really meant is an inertial navigation system. These fuse data from accelerometers, gyros, compass, and optionally GPS for a more accurate dead-reckoning. I have used the ...


1

Ultrasonic means above audible range, Sonar may be within the audible range In my opinion the ultrasonic being more precise also may come with higher price.


1

The main difference is, SONAR (originally an acronym for SOund Navigation And Ranging) is used underwater and uses low frequency sounds (100-500Hz) as well as high frequency sounds (ultrasound, etc). Ultrasonic sensors are used mostly over the terrain and limited to high frequency sounds.


1

I asked this question before in here when I had no idea what SLAM problem actually is. I realized later this question was a sign indicates that I have no idea about the problem. The word SLAM is an acronym for Simultaneous Localization And Mapping which indicates that the environment must be part of the problem or in other words the robot needs to navigate ...


1

Having an overhead camera (like a single low cost webcam if needed). Ultrasonics is meant to be directional while cameras are not meant to be. The downward facing camera placed at a height and horizontally centered over the area can detect robot and obstacles in Cartesian coordinates and that information can be transferred to the moving robot using Bluetooth ...


1

So this is really a hard task. Estimating the position of a AUV is still a large challenge even in research. There are sensors like as DVL (Doppler Velocity Log) available that can estimate the speed over ground. These sensors working okay, but they only estimating the speed. These devices are precise enough for your use case BUT these devices are to large ...


1

I think the time-of-flight cameras would suffice for your application and are cheaper than laser scanners (which are much more precise).


1

http://hackaday.com/2014/01/23/lidar-with-leds-for-under-100/ This could be a good alternative to lidar. I dont know if it is commercially available.


1

Depending on what your actual use case is, you might be able to use Stereo cameras: Needs more processing power on board, usually smaller field of view Kinect There are some kickstarter projects that promise some low cost alternatives as well. Example


1

We are using the P900 multibeam sonar. So far our interface hasn't any problem. But we requested a new version of the library from teledyne which works now in our case. sonar = new BVTSDK::Sonar(); head = new BVTSDK::Head(); int ret = sonar->Open("NET", hostAddress); //error handling ret = sonar->GetHead(1, head); //again error handling I will ask ...


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