Transport vehicle

A transport vehicle for transporting an article, the transport vehicle comprising:

• a holder configured to hold the article;
• a lifter configured to lift and lower the holder;
• a control device;
• and
• a power supply unit configured to receive power from an external source and supply the power at least to the lifter, and
• wherein:
• the lifter comprises a lift drive and a restrictor, the lift drive is configured to drive the holder to be lifted and lowered, and the restrictor is configured to mechanically restrict a lifting and lowering operation of the holder performed by the lift drive, and
• the control device comprises a voltage monitor configured to monitor a target voltage being a voltage applied from the power supply unit to the lift drive, the control device is configured to perform a preliminary restriction operation to activate the restrictor in response to the target voltage being lower than or equal to a determination threshold, and the determination threshold is lower than a voltage of the power supply unit in normal operation and higher than a lower limit voltage being a minimum voltage to allow the lift drive to keep the holder at a position in a lifting direction.