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View Full Version : Can a BS2 act as a Servo mixer?



Joe west
04-25-2006, 02:11 AM
I am looking to incorporate 2 gyros into my biped project to add ‘balanced gait’.
I would like to know if a BS2 can modify the signals sent to the ankle servos from my SSC-32 running its Sequencer. i would like it to run independently from the ssc-32, no新erial communication between the two.

http://www.geocities.com/joe_west_pics/GyroController.JPG

Its I/O’s will need to be新etup for receiving and sending servo pwm info, modifying the 1-2ms signals depending on the the gyro inputs, I would like the Servo signals modified by up to +/- 0.2 ms, depending on the gyro signal amount (The gyro Signals are also 1-2ms搆ulses depending on tilt, 1.5ms is no tilt). Is this possible?


Each foot’s modified signals will also have to take into account the ankle servo position that controls the amount of twist in the leg. Or ‘z axis’

http://www.geocities.com/joe_west_pics/ankletwist.JPG

If the X axis gyro mounted in the body registers forward tilt (sending a 2ms pulse instead of usual 1.5ms to the BS2), then it will need to modify the right ankles X axis servo signal to compensate (by decreasing pulse length by 0.2ms).
Because the left foot has turned left, both X and Y Servo signals need to be modified in the ankle (a 0.1ms decrease to both).

Is this possible with the BS2, or would another microcontroller be more suitable?

Is it also possible暗o split the servo cables so that power lines go directly from the SSC- 32 to the servos, but the signal wires travel from the SSC-32, to the惹tamp, and then the servos, or will there be problems with grounding.

any comments from BS2 owners with practical experience with a similar system would be appreciated.

Chris Savage
04-25-2006, 07:50 AM
Joe,

毽 We have examples of the BS2 being used for servo mixing. Attached is a simple one we use to drive around a BOE-Bot using a single stick from a 4-Channel Radio (using 2 channels).

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Chris Savage
Parallax Tech Support
csavage@parallax.com (mailto:csavage@parallax.com)