Sensing the speed of the footbot

Requests regarding how to set up experiments in ARGoS.
mallwright
Posts: 33
Joined: Tue Apr 17, 2012 11:15 am

Sensing the speed of the footbot

Postby mallwright » Thu May 31, 2012 2:22 pm

So, I have been taking readings from the FootBotEncoderSensor and the FootBotWheelSpeedSensor to see if I could detect when the footbot had collided with an object based on the change in speed.

However both these sensors seem to only return the value that I set to the FootBotWheelActuator (or in the case of the FootBotEncoderSensor 1/10 of the assigned speed). I would expect this behaviour from the FootBotWheelSpeedSensor, but shouldn't the FootBotEncoderSensor be approximating the true linear speed of the footbot? Unless slip between the ground and the surface of the wheel is being simulated, this doesn't make a whole lot of sense to me...

This is the output of logging the left and right readings:

ENCODER: Left = 1.000000, Right = 1.000000
SPEED: Left = 9.999999, Right = 9.999999
ENCODER: Left = 1.000000, Right = 1.000000
SPEED: Left = 9.999999, Right = 9.999999
ENCODER: Left = 1.000000, Right = 1.000000
SPEED: Left = 9.999999, Right = 9.999999
ENCODER: Left = 1.000000, Right = 1.000000
SPEED: Left = 9.999999, Right = 9.999999
ENCODER: Left = 1.000000, Right = 1.000000
SPEED: Left = 9.999999, Right = 9.999999
ENCODER: Left = 1.000000, Right = 1.000000

I can see in my simulation that once the footbot is pushing a block ~1kg that the speed has dropped approximately to about 1/4 of the free running speed, however the readings from the encoder and speed sensor do not change...

As an alternative for my purpose I could use the accelerometer to detect the changes in speed, although this seems a bit of a indirect method.

Any thoughts?

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