Servo inquiry for rugged application

Technical Support
1

Good Day

I’m looking for a servo solution for a system.

Requirements:
• Min. 100Ncm torque
• IP67 waterproof
• Temps down to -20°C
• Absolute Encoder (no homing possibility – needs to keep position after power loss)
• Speed is irrelevant
• We only need about 140° of movement. No continuous rotation.

Basically I’m looking for something that can duplicate an RC-Servo but with digital control. PWM has too much interference.
Does Dynamixel have something that fits these requirements?

Thanks in advance for the answers

2

The best fit for the specs that you shared would probably be the XW430.

The only points of concern are:

  1. The -20°C operating requirement is pretty tough, but if you can warm up the servo externally or if it’s going to be in a relatively well sealed enclosure that traps heat, it might be achievable.
  2. The absolute encoder will reset to a position within a single rotation after a poweroff. It doesn’t sound like that will actually have an impact in this application, since you mentioned you only expect to be moving within 140°, but it’s still important to keep in mind just in case.
3

Thank you for your reply!

It’s neither warmed nor enclosed unfortunately but i could try insulating it a bit. I used a Nema23 stepper before and it survived so maybe this will too… usually the temperatures drop at night when the servo is not active.

The thing is, it’s really not allowed to make a full rotation because of wires. Does it depend in which position it stands when powering off? Do you know how exactly the referencing works?

Best regards
lukas

4
  1. In that case, you’ll almost certainly need to add an external heating element or something, to get the actuator moving after freezing overnight. The grease inside the servos will freeze solid at that temperature, normally I’d recommend simply replacing the grease with something that won’t freeze, but that’s not an option for the IP rated XW series.
  2. The standard position mode behavior is well suited to this single turn operation, it will remember it’s absolute position within the single rotation through power cycles and even when it’s moved while unpowered.