Operation Overview

Operation Overview for XM2 Labs SLG-20 Retractable Landing Gear

Operation on boot

When the SLG-20 control board is powered on, it first checks to see if the servos have been calibrated. (It does this by checking a saved parameter, see the Parameter System and Auto Calibration & Servo Insertion pages)

If the servos have not been calibrated, the control board will go to the Error state, which will not allow the legs to operate. This is to prevent damage to the servos or mechanism which can occur if the system is operating without calibration.

If the servos have been calibrated (When you receive your SLG-20 System, they will be calibrated), then the system boots normally in the standby state.

Normal operation

While operating, the control board will read both input signal and commands from the console interface.

Either the input signal or the console interface can be use interchangeably to command the legs to be RAISED or LOWERED. The last actioned command is given priority, so the legs could be RAISED by the input signal, and then LOWERED by the console interface.

If the input signal is lost while the legs are UP, the legs will automatically LOWER and allow the drone to land safely. While the input signal is in failsafe state, the legs can still be RAISED manually through the console interface. This can be useful for bench testing without an RC Receiver.

Movement Sequence

When the legs are commanded to RAISE or LOWER:

1. (Powerup State) When the servos are powered, the control board takes a few hundred milliseconds for them to boot.

2. (Move State) The servos will move for approximately 2 seconds to raise or lower the legs.

3. (Powerdown State) The servos are kept powered in the final position for a few hundred milliseconds, allowing the movement to be completed.

4. (Standby State) The servos are powered off to allow the springs to lock out the mechanism.

Changing direction during the movement sequence

While the system is in Powerup or Move state, it is possible to change the direction of movement by reversing the input signal or sending the opposite command from the console interface. While the system is in Powerdown state, the system will be unresponsive until in Standby state. Any commands given during Powerdown state will commence after the system moves into standby state.

More information

Control StatesAuto Calibration & Servo Insertion