I have looked over many of the smart servos you offer and have found the Dynamixel AX-12A and MX-28T, as well as the Herkulex DRS-0101 and DRS-0201 models to be good candidates for my application. My big problems is that I have never worked with servos and actuators before. Could you recommend the appropriate products that I would need to buy in order to control the motion of the servos, as well as the software that I would need to program them.
So you know what to suggest, let me briefly describe my application. I need to translate a DC voltage signal into a position on the servo. For instance, the Herkulex are rated for accurate motion from 0 to 320 degrees. 0 VDC would translate to the 0 degree position, and 10 VDC would translate to the 320 degree position moving in a clockwise direction. Any advice you can give regarding the proper selection of components would be GREATLY appreciated.
Hmm, would the HS-785HB be sufficient for your needs?
The Dynamixel and HerkuleX servos are smart servos that are much more complicated to use than servos that use standard R/C PWM signals. If the HS-785HB has the torque and speed requirements necessary, we would recommend using it with an Arduino board such as the BotBoarduino. If this is sufficient for your needs, you would be able to make your code by simply adjusting the the Knob example (File -> Examples -> Servo) that’s included with the Arduino IDE.
Since the analog input on these boards is maximum 5V, you would need to use some resistors to build a voltage divider: two 4.7k in series should do fine.
If you would prefer to use the Dynamixel or HerkuleX smart servos, let us know and we can see what we would recommend.
I looked at the HS-785HB, and I don’t think it would work well for my application; at least not nearly as well as the smart servos would. I am trying to build a device which simulates a pressure gauge (0 - 5000 psi). The needle would be attached to the horn. 0 degrees would be 0 psi, and 5000 psi is at 270 degrees CW travel from there. Because I need to be as precise as possible regarding the positioning of the horn all throughout the range of travel (definitely sub-degree resolution), as well as being highly consistent/repeatable (thus the need for a device with a fine position-sensing feedback), I don’t think that the HS-785HB would have good enough resolution; as the controllers I’ve seen have a maximum of 10-bit (1024) resolution, and 1260/1024 is certainly not sub-degree resolution. for these reasons I would definitely like to try the Dynamixel or HerkuleX smart servos.
If possible, would you please contact me offline from the forum (the email address that notifies me when replies to posts are posted?) with a phone number or email where I could consult with you directly regarding the best solutions for my application. I am unconcerned regarding the complexity of the smart servos. I am an engineer for the U.S. Navy, and have extensive experience integrating various technologies into my systems. All I need is a good foundation (all the proper hardware, software, training materials (Thank God for youtube!)) from which to learn from and I can usually take it from there or find someone here at work that can tutor me and get me up to speed with what I need to know to make the system work.
Thanks for the details. We don’t currently provide consulting by the phone, but we can still assist in product selection here.
Base on what you’ve explained, either of the smart servos servos should work. Do you have a preference between using an Arduino board to control the servo, or a computer?
Robotis doesn’t seem to provide any sample code for the Arduino, so if that’s your preference, we would recommend HerkuleX. Dongbu has provided some sample code here, and it should be very easy to adapt the UNO_one_motor_move_angle.ino sample to make servo movements based on an analog input signal. There is some unofficial libraries for Dynamixel, but they seem hit-and-miss sometimes.
If you want to use a Windows PC, then there is sample code for both series. For HerkuleX, it’s the same link as above, and for Dynamixel the SDK is available here. To get the analog input with a PC, we would recommend the Phidget 2/2/2 module. It’s input is also limited to 5V, so you would still need the voltage divider.
