Abstract:
Abstract:A suspended vibratory actuator for removing camellia fruits from a plant was designed to improve the picking efficiency while reduce the cost. This present picking actuator mainly comprised a vibratory head device for clamping a fruit plant, and a column mechanism for controlling the vibratory head. The column mechanism can make the rotation and lifting of the vibratory head, and consequently the vibratory head can hold the fruit tree while generate an exciting force. A double eccentric structure was used for the excitation mechanism, and a hydraulic cylinder as an actuator was used for the clamping mechanism. A harvesting dynamics model combined the picking actuator and the camellia oleifera tree was established to obtain the amplitude expression and influencing factors of the system under the steady-state response. The simulated results showed that there was a periodical change in the displacement, velocity and acceleration of the fruit tree, whereas the amplitude and phase angle depended on the system itself regardless of the initial conditions. The three-dimensional modeling using ANSYS method was also established to create a flexible body model of the camellia oleifera tree according to the field measurement. The ANSYS and ADAMS software were used to systematically analyze the rigid-flexible coupling mechanism of the picking actuator-chamber tree. The picking frequency in this simulation was 12 and 15 Hz while the clamping height was 1 300, 1 000 and 700 mm, respectively. The acceleration curve of the side branch was used to obtain the movement track of the fruit tree clamping position, and the relationship between the acceleration of the side branch and the clamping height/frequency. The obtained results showed that there was a periodical change in the acceleration of the side branch, whereas there was a reciprocating linear motion in the clamping position, when the fruit tree was excited by the double eccentric mass. The speed of the side bracket increased with the increase of the clamping height and the frequency. When the picking frequency was 15 Hz and the clamping height was 1 300 mm, the maximum acceleration of the side branch was 2.84×105 m/s2. This finding inferred that the picking actuator showed good feasibility. The tea picking machine was also used for the field picking test to verify the simulated results. The experimental results using the range analysis method demonstrated that the fruit-drop rate and the flower-drop rate increased with the increase of the picking frequency, and the fruit-drop rate increased with the increase of the height of the buck, whereas the flower-drop rate decreased with the increase of the grip height. The high fruit-drop rate of 95.1% and the low flower-drop rate of 4.8% were achieved when the frequency was 15 Hz and the clamping height was 1 300 mm.