View Full Version : [Question(s)] PhantomX Reactor Robot Arm servo failure?

12-05-2014, 03:34 PM

This is my first time posting to this forum. And I have a question about the PhantomX reactor Arm robot.

My group at work has purchased 5 or these robot arms and we assembled and programmed the servos according the building guide on the website. After assembling them we were even able to get the robots to run the code that was given to test the arms and they worked perfectly.

Are issue came in when we tried to run a durability test by setting the reactor test code on a loop to see if there would be any failures. Well when we did that after about 15-20 minutes of constantly running, servos 2 & 3 failed and the arm just went "limb" at that point. Has anyone had this issue before with this robot arm? for me it doesn't make sense that they would run perfectly then all of the sudden fail? Anyone have any suggestions on why that might be happening?


12-05-2014, 05:58 PM
Sounds like those servos went into overheat safety. Did you try and power them down for a bit and let them cool down, then power back up?

12-05-2014, 05:58 PM
Remember these actuators have temp sensors in them.

12-07-2014, 07:28 PM
Thank you for the reply.

I have powered them down and let them cool. and once i do that they function perfectly again. but then if i let them run continuously they fail again. So it does sound like they might be going into overheat safety. So it looks like they were not designed to be ran for a long period of time. Thank you for your help.

Were did you find the information about the servos having an overheat safety feature?

12-07-2014, 07:36 PM

The servos can operate for very long periods of time, but the servos will create more heat when trying to control a large load and/or move the load quickly. What are you moving with the arms?

12-07-2014, 07:59 PM
Thank you for the link. It helped.

We have not tried to lift anything with them yet. I have just simply been letting the arm run the test code (http://learn.trossenrobotics.com/interbotix/robot-arms/17reactor-robot-arm/26-phantomx-reactor-robot-arm-build-check) in a loop to see if anything like this would happen. The arm runs the motion in the video until servos 2 and 3 fail, which are the servos at the base of the arm. When I get back into the office I will set a timer to see how long the arm runs until failure.

12-08-2014, 01:35 AM
You are correct: These arms are hobbyist-level arms, not designed for long-term continuous duty.
You should be able to get a better result by pausing after each iteration (for something like a 50% duty cycle -- exactly which duty cycle you use depends on environmental factors and load.)
Separately, there are other arms based on increasingly more powerful servos. Although, when you get to the Dynamixel Pro servos, you might as well compare to a used existing industrial robotic arms at $3,000 and up...

12-08-2014, 10:35 AM
Can you load the reactor arm test code and then open the serial terminal, and give us the output?