3.1.1. Different Stages of Vertical Transportation

Due to the actuator movement from the start position to the stop position, as shown in Figure 5a, the hanging grape cluster started to vibrate, and the magnitude of the cluster's vibration in terms of hanging force was measured. Hanging force was measured in the form of analog signals. These force signals of the hanging cluster during vertical transportation and placing were divided into 5 phases, as shown in Figure 5b, for a better understanding of the dropping mechanism or berry deflection of the hanging grape cluster at different speed and acceleration excitations.


**Figure 5.** Vibration characteristics of the grape cluster during vertical transportation: (**a**) phases of the grape cluster; (**b**) force signals.

#### 3.1.2. Different Excitation Transmissions during Placing

It is difficult to observe the deflection mechanism of berries during vertical transportation and placing with the naked eye due to the short interval of time. Therefore, a high-speed camera was used to analyze the deflection of berries at different excitations during the transportation placing cycle, as shown in Figure 6. When the grape cluster collides with the packaging surface, the excitation moves from the packaging material to the whole grape cluster, which causes damage in the form of berry fall and decay. There are two types of berry dropping mechanisms observed from the high-speed photography images during the placing of the grape cluster at different speed and acceleration excitations [8] applied to the hanging grape cluster, as defined below. Excessive bending of the main rachis was observed during the robotic placing of the grape cluster. The impact of the packaging surface on the whole grape cluster after contact was divided into two categories, as shown in Figure 6c.

1. Bottom Berries

The impact excitation comes from the packaging materials after the collision, which caused the deflection of the bottom barriers due to the torsional load in between the berry and the pedicel.

2. Top Berries

Excitations are transmitted to the whole cluster after striking the packaging materials, and upper barrier deflection was observed due to the vibration or bending of the main rachis.

**Figure 6.** Load on the berries of the grape cluster during the placing phase: (**a**) grape cluster; (**b**) transportation load; (**c**) placing load.
