outdoor autonomous robot [closed]

Question

i had search over google and found out more or less some sensor that i could use like sonar, gyroscope, accelerometer,magnetometer and gps and 2d lidar (which is less expensive, around $300) i have cost budget so i couldnt go for those expensive devices.

im new to robotic. thus i want to ask for some recommendation. i want to build a robot which satisfied these following feature

1. works on outdoor. look at the image above with some description here: blue line is the border. red line is the path. black line is the building.
2. when the robot at point A, and i input point B. the robot should be able to find a path from point A to B
3. if point x is blocked, it should be able to find a way to point B via point Y
4. ground is not flat. thus there might be need sense some higher ground level to avoid collision and recalculate the position of the robot
5. works on day and night

therefore, my question is: what is the best device/sensor i should get to satisfy my features above. or probably any technique i could use? Please kindly share with me. maybe there is something i miss out on my research

Gps is good but the error is around 6m.. that is too large fusion of gyroscope, accelerometer, magnetometer to get a correct position and direction is kinda difficult(oblu maybe)

founding: i found 2 device that could help me with that

1. ZED stereo camera which works on 0.5m up to 20m.($499)

2. Intel RealSense 435i which works 0.1m up to 10m with IR.($200) both are not working so good in dark area even with IR. but i think a lighting could be installed to help with that

any other device recommendation ?

Answer 1

This is a broad topic you've opened up here. My contribution:

1. It all comes down of the robot specs. For example, is it a wheeled robot or a legged.? What size of terrain shall it explore? in the scale of meters, centimeters, tens of meters? etc... I think, you should write down all questions you could think of, that will help you specify your sensor options.

2. I think you need a redundant sensor system. For adequate precision it is inevitable. Multiple sensors that are inaccurate on their own, but combined they give accurate results. Also your sensor data and control data shall be piped through some sort of filtering algorithm to increase performance. It will gain complexity, but that is your tradeoff for accuracy.

3. You could for example have a nice IMU sensor, it provides 3D accelerometer and compass data. That you can use to determine your relative position, speed, acceleration.

4. Are you using a wheeled robot? You could use the wheel rotation to determine the relative path your robot has achieved. It may be really inaccurate, since the given terrain, wheel skidding etc.

5. If you have the two above you may as well can apply an IR or ultrasound sensor, to increase precision.

6. You still can use a cheap mono camera, to estimate speed and direction.

7. Also important, how you utilize your sensor data. Building a nice visual map based on the sensor data could help a lot in navigation. AI that can do some extra analysis on the shapes on the map.

Probably, most of the things above were also known for you, what I tried to show here is, that if you want to achieve high or just adequate performance, You can't get away with a simple mighty sensor.

As a concrete example: my master work was a multilegged robot with a single sweeping ultrasound sensor. It had an algorithm, that has built up a map based on the sensor input and run the analysis on it. It actually have solved relatively complex static and dynamic maze problems using the real robot hardware. But, it has flawed accuracy, caused by the monosensory and error in calculated position, that obviously can't reflect measured position, in case of a legged robot, without additional sensors. I hope I can at least give you some ideas of thinking.

Answer 2

The question is about the hardware of a robot. What is not asked is how to program a robot by software, this would be an Artificial Intelligence question. I belief, that software is more interesting but to answer the question we have to stay at the hardware side. Hardware and mechanics were invented in the 19th century during the industrial revolution. Toys from that area are sold under the brand name Meccano. If somebody likes to build physical robots or is interested in hardware devices, this is a reference. According to the website, Meccano robots have an infrared sensor as a standard sensor for detecting obstacles. This device can be used for indoor and outdoor problems as well. A dedicated outdoor infrared sensor is often named as laser/IR sensor.

So my recommendation is to focus only on one sensor type which is infrared and use this hardware for obstacle detection, navigation and pathplanning at the same time.