With a 2 wire system and no sensor for feedback there is no way for the controller to determine where the 0 point is located. Also with only 2 wires this is a simple DC motor, R+ and B- go one direction where R- and B+ go the other. A stepper motor would have at least 3 wires, usually 5 and that could use different input voltages to reference a different position. A standard DC motor is not capable of that function. So that being said what is being used as the feedback loop for the system? It may be just a compass built into the AP that blindly moves the rudder to see where the deviation is and then uses the compass signal as the feedback. This approach is mechanically simple but software wise more complex. It doesn’t require external hardware and if fairly user friendly as it is self calibrating. The software that performs the locating and self calibrating on the other hand is far more complex, and some engineer at the factory has tackled that job for us already.
The more common way is the use of a rudder position sensor. The 4v 0v 8v you are talking about sounds to me like there is a sensor somewhere in the system giving the voltage in reference to the rudder’s angle. This is usually done with a potentiometer and 3 wires. V+, G, Signal. This allows the AP to know where the rudder is and thus much simpler calculations as to where the corrections need to be made to move the rudder. Slightly more complex in the mechanical aspects but far simpler in the software side.
Im guessing you may already know all of this, but if not there ya go. Now about the Arduino setup. You want to keep the existing motor drive with the new AP. Ok… what is needed more than anything else is the specs from the original motor drive. What is the amperage and voltages it is designed to work at? Being a simple 2 wire DC motor makes things really simple, but the driver chips in the new AP will need to be suited for that motor. Newer DC motors can perform the same amount of work with far less energy used, and thus the driver chips in the AP are not going to be as robust. This equals cheaper, but not necessarily cheap. If your old motor is rated at 12v 2a for example and your new AP can handle a 12v 5a DC motor you are good to go, just plug and play, your motor will never ask for more than 2 amps thus the drivers will be well within their design limits. Remember it’s the motor that will determine the needs of the driver.
If you have a motor that is rated at 12v 2a again but your new AP can handle an output of 12v 1a, it is not a good match. You may be thinking this will never give my motor too much power so I will be safe, but you would be wrong. With an output of only one amp, the motor will constantly be trying to pull 2a and thus running your drivers at full or even over full capacity, and this will release all that smoke the designers put into those chips. Again it’s the motor that determines the needs of the driver.
So with all of this, i hope it helps understand what the needs will be for developing your new system. As someone who tinkers with Arduino devices (mainly for model railroad automation) it would be interesting to see what you come up with.
The more common way is the use of a rudder position sensor. The 4v 0v 8v you are talking about sounds to me like there is a sensor somewhere in the system giving the voltage in reference to the rudder’s angle. This is usually done with a potentiometer and 3 wires. V+, G, Signal. This allows the AP to know where the rudder is and thus much simpler calculations as to where the corrections need to be made to move the rudder. Slightly more complex in the mechanical aspects but far simpler in the software side.
Im guessing you may already know all of this, but if not there ya go. Now about the Arduino setup. You want to keep the existing motor drive with the new AP. Ok… what is needed more than anything else is the specs from the original motor drive. What is the amperage and voltages it is designed to work at? Being a simple 2 wire DC motor makes things really simple, but the driver chips in the new AP will need to be suited for that motor. Newer DC motors can perform the same amount of work with far less energy used, and thus the driver chips in the AP are not going to be as robust. This equals cheaper, but not necessarily cheap. If your old motor is rated at 12v 2a for example and your new AP can handle a 12v 5a DC motor you are good to go, just plug and play, your motor will never ask for more than 2 amps thus the drivers will be well within their design limits. Remember it’s the motor that will determine the needs of the driver.
If you have a motor that is rated at 12v 2a again but your new AP can handle an output of 12v 1a, it is not a good match. You may be thinking this will never give my motor too much power so I will be safe, but you would be wrong. With an output of only one amp, the motor will constantly be trying to pull 2a and thus running your drivers at full or even over full capacity, and this will release all that smoke the designers put into those chips. Again it’s the motor that determines the needs of the driver.
So with all of this, i hope it helps understand what the needs will be for developing your new system. As someone who tinkers with Arduino devices (mainly for model railroad automation) it would be interesting to see what you come up with.
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