How to measure and control an Avoidance car's turn angle?

Thread Starter

LAOADAM

Joined Nov 21, 2018
835
Hi,
I am doing a Arduino Robot car ref. to:
my question is how to measure and control the Avoidance car's turn angle when the Ultrasonic sensor detected an Obstacle?
I don't think the HMC5883L kind of compass or even GPS module can work if in-room.
Thanks
Adam
 

Ya’akov

Joined Jan 27, 2019
6,854
Hi,
I am doing a Arduino Robot car ref. to:
my question is how to measure and control the Avoidance car's turn angle when the Ultrasonic sensor detected an Obstacle?
I don't think the HMC5883L kind of compass or even GPS module can work if in-room.
Thanks
Adam
The earth's magnetic field is not blocked the way GPS satellite signals are. So the compass will always work unless there are large magnets or big metal structures nearby. The compass will give you an absolute bearing relative to the earth's field but navigation will have to be done by dead reckoning or some sort of triangulation with, say, infrared beacons.
 

Thread Starter

LAOADAM

Joined Nov 21, 2018
835
The earth's magnetic field is not blocked the way GPS satellite signals are. So the compass will always work unless there are large magnets or big metal structures nearby. The compass will give you an absolute bearing relative to the earth's field but navigation will have to be done by dead reckoning or some sort of triangulation with, say, infrared beacons.
Thanks.
it is a solution.
 

nsaspook

Joined Aug 27, 2009
10,676
Magnetometer based navigation is noisy and often inaccurate. Sensor fusion with 9DOF is the recommended solution for solid motion tracking data.
https://www.embeddedcomputing.com/technology/analog-and-power/basics-of-6dof-and-9dof-sensor-fusion
Thanks to the third sensor and sensor fusion algorithms, the 9DOF tilt-compensated and gyro-stabilized eCompass is now gathering the best data from all three sensors, identifying and compensating for the flaws of some with the strengths of the others. It provides an accurate, low noise, smooth but responsive estimate of the device orientation angles, rotation speed, linear acceleration, Earth gravity, and geomagnetic fields; delivers sensor calibration error information; and is more resilient to magnetic interferences. The outcome greatly exceeds the sum of individual sensors’ contributions, which is the essence of sensor fusion.
http://wiki.ros.org/razor_imu_9dof
 

nsaspook

Joined Aug 27, 2009
10,676
I suspect sensor fusion is out of scope for this project/builder but who knows?
Most of the sensor fusion software complexity (hardware and software) is canned for Arduino systems. It's worth the extra effort to understand why sensor fusion is the modern standard for motion tracking.
 

Ya’akov

Joined Jan 27, 2019
6,854
Most of the sensor fusion software complexity (hardware and software) is canned for Arduino systems. It's worth the extra effort to understand why sensor fusion is the modern standard for motion tracking.
While I agree completely with you, the level of questions in this thread suggests to me the technology is more suited to a future version. I could be wrong, but I am trying to maximize the chances of success for the TS.
 
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