[swraight]

We're also using a Dart, and have had similar issues when overrunning the stops. Use of the hall effect sensors to restrict the stroke really is essential. We have also found it necessary to use software to decelerate the motor as it approaches the limits. When running at high speed near the limits, the motor would not stop quickly enough to prevent overrunning the limit and hitting the mechanical stop.

Unfortunately, the mechanical stops inside the Dart are not strong enough to withstand the full force the Dart is capable of putting out. If you've over extended the actuator and now find that it's slipping, the only solution we have found is to completely disassemble and reassemble with new E-clips (and new Loctite on the threads of the lead screw nut).

We're planning on purchasing a spare Dart to swap out quickly if the one on our robot is damaged so we can still play while we repair the damaged one... Expensive, but it'll keep us in the game.

Good luck with it!