This is the first controlled tumble of an over-constrained tetrahedral robot ever! This was a joint effort with Hope College and NASA to refine the concept of a tetrahedral rover. The summer team consisting of Dr. Miguel Abrahantes, Luke Wendt, Aaron Silver and Dan Lithio developed the control scheme and hardware for its autonomous control.
Our Controller:
We are using an onboard processor from IFI that reads in 2 analog signals from a reference passed from the laptop. The analog signals multiplex to correspond to each strut let the processor know what length they should be. The struts report their lengths via spring loaded string potentiometers we constructed from retractable key chains. The struts themselves are made from power car antennas. The on board control is a simple PI control where the addition of error and integral error defines how much power to send to the motor. The non-responsive dead-zone of the motor was corrected for. The power is controlled with 7 PWM signals out of the processor. Alternate struts are controlled because we never need to control the 3 floor struts. The PWM goes to a Victor 883 electronic speed controller which is capable of reversible polarity and is provided with a 12V voltage source.
This is the first controlled tumble of an over-constrained tetrahedral robot ever! This was a joint effort with Hope College and NASA to re...all »This is the first controlled tumble of an over-constrained tetrahedral robot ever! This was a joint effort with Hope College and NASA to refine the concept of a tetrahedral rover. The summer team consisting of Dr. Miguel Abrahantes, Luke Wendt, Aaron Silver and Dan Lithio developed the control scheme and hardware for its autonomous control.
Our Controller:
We are using an onboard processor from IFI that reads in 2 analog signals from a reference passed from the laptop. The analog signals multiplex to correspond to each strut let the processor know what length they should be. The struts report their lengths via spring loaded string potentiometers we constructed from retractable key chains. The struts themselves are made from power car antennas. The on board control is a simple PI control where the addition of error and integral error defines how much power to send to the motor. The non-responsive dead-zone of the motor was corrected for. The power is controlled with 7 PWM signals out of the processor. Alternate struts are controlled because we never need to control the 3 floor struts. The PWM goes to a Victor 883 electronic speed controller which is capable of reversible polarity and is provided with a 12V voltage source.
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