Article transfer apparatus

1. An article transfer apparatus comprising:

a holding portion comprising at least one suction pad that holds a target article;

a robotic arm that moves the holding portion; and

a controller that controls the holding portion and the robotic arm, wherein:

the controller performs hold control to hold the target article located at a movement origin, movement control to move the target article held by the holding portion into a movement region of a movement destination, and hold-release control to release hold of the target article located inside the movement region,

the article transfer apparatus further comprises a reference detection portion that detects a reference position of the target article held by the holding portion, and

the controller controls the holding portion and the robotic arm so as to hold a reference holding position set based on a type of the target article in the hold control,

wherein the controller further performs:

reference detection control to detect, by the reference detection portion, the reference position in a state in which the target article is lifted from the movement origin,

determination control to determine a positional relationship between the holding portion and the reference position based on a result of detection by the reference detection control, and

position calculation control to calculate, based on the positional relationship determined by the determination control and a positional relationship between the reference holding position and the reference position, a movement destination position that is a position, of the holding portion at the movement destination, at which an outer edge of the target article held by the holding portion fits within the movement region, and

wherein the controller controls the robotic arm so as to move the holding portion to the movement destination position in the movement control.

2. The article transfer apparatus according to claim 1 , further comprising:

a gravity center detection portion that detects a gravity center position, as the reference holding position, of the target article located at the movement origin, and

wherein the controller:

controls the holding portion and the robotic arm so as to hold the gravity center position of the target article located at the movement origin in the hold control, based on a result of detection by the gravity center detection portion, and

detects the gravity center position of the target article as the reference position by the reference detection portion in the reference detection control.

3. The article transfer apparatus according to claim 1 , wherein the reference detection portion includes at least one reference image capturing device that captures an image of the target article, and includes a determination unit that determines the reference position of the target article based on image capture information obtained by the reference image capturing device, and

wherein the reference image capturing device is coupled to the holding portion so as to move together with the holding portion.

4. The article transfer apparatus according to claim 1 , wherein a box-shaped housing portion that is open upward is installed at the movement destination, and the movement region is set on a bottom portion of the box-shaped housing portion.

5. The article transfer apparatus according to claim 3 , wherein

the robotic arm includes an arm having a distal end portion to which the holding portion is coupled, and

the at least one reference image capturing device includes two reference image capturing devices which are on either side of the arm so that the arm is positioned between the two reference image capturing devices.