Motion characteristics of the robotic arm can dominate the performance of mango harvesting vehicles during picking. In this study, the kinematics analysis was carried out using the multi-body dynamics theory. An initiative was first undertaken to conceptualize and engineer a mango harvesting vehicle. The higher efficiency and labor-saving harvesting was achieved within tropical agricultural regions, compared with the manual. The equipment was designed with walking, lifting, and harvesting functions that were tailored to the Hainan mango planting environment, growth and harvesting agronomy. The core components of the vehicle included a hexapod bionic walking device, a robotic arm, and an end-effector. However, the harvested mangoes were of a modest size within the available operational range, resulting in a low load on the harvesting vehicle. The kinematics model of the robotic arm was established using the Denavit-Hartenberg (D-H), according to the growth of mangoes, the geometric and vector configuration of the robotic arm. The variable separation was employed to conduct the inverse kinematics on the joint variables of the robotic arm. The end-effector motion space planning was also conducted to systematically clarify the motion. The trajectory planning showed that the stability of end-effector motion fully met the motion requirements of the robotic arm during picking. The dynamic model of the robotic arm was constructed by the Lagrangian method. The forward and inverse dynamics simulation was carried out on the joint motion of the robotic arm under constant torque and only periodic swing using Adams software. The dynamic analysis showed that there was a certain periodicity movement under the constant torque in the telescopic and swing devices. The peak of the stage reached about 1.25, 2.3, and 4.15 s. In the case of only oscillating periodic motion, the driving torques of the rotating and oscillating device were approximately cyclically changed, with the peak values of 72.5, and 52 N·mm, respectively, indicating two maximum values in one motion cycle. A vibration analysis was also performed to determine the dynamic performance of the robotic arm. The feasibility of the multi-body dynamics model was verified using linear modal calculations and experiments. A vibration element was then created at the bottom of the robotic arm, in order to explore the effect of the bottom vibration excitation on the motion of the end-effector. The frequency response curve showed that the end-effector was subject to the greatest vibration in the y-direction during the operation of the robotic arm, leading to the overall vibration. Moreover, there was a relatively gentle amplitude in the y-direction between 0-10 Hz. Parametric calculations were then performed, where the y direction of the end-effector was defined as the target for optimization. The maximum response value of the robotic arm was 0.1665, indicating the minimal vibration to fully meet the specified smooth operation. In conclusion, the mango harvesting vehicle can be an effective solution to the challenges posed by manual mango picking in tropical agricultural areas. The trajectory planning shared the efficient and precise movement of the end-effector, meeting the requirements of mango harvesting. The multi-body dynamics model of the mango-picking robotic arm was verified by experiments. The findings can provide a strong reference for the picking performance of the robot arm for its high reliability and stability.

Aiming at the problems of the difficulty to deal with the waste of banana stems after harvest and the high labor intensity and low efficiency of banana farmers, a banana stem roller squeeze dehydrator was designed, which aimed to realize the squeeze dehydration of the whole stem of banana stems in order to obtain the juice and fiber of banana stems. The banana stem roller squeeze dehydrator was mainly composed of juice storage tank, dehydration frame, upper pressure roll group, lower pressure roll group, transmission mechanism, feeding mechanism and so on. First of all, according to the characteristics of banana stems, such as easy winding and not easy to crush or slice, a four-stage roller squeeze mechanism with gradually reduced opening was designed. The four-stage roller squeeze mechanism was a classification squeeze, the first three stages of the roller were responsible for conveying and preliminary squeezing, and the fourth stage of the roller was mainly dehydrated. The upper and lower stages of the roller gap can be adjusted to adapt to different specifications of banana stems. The adjustment of the gap of the first stage of the roller was for the convenience of feeding, and the adjustment of the gap of the fourth stage of the roller was for the remarkable dehydration rate. The pattern design of the roller surface increased the friction between the roller and the banana stem, ensuring the smooth juice discharge of the squeeze mechanism and preventing the banana stem fiber from winding the roller. The transmission mechanism was designed, which made the angular velocity of the four-stage roller remain the same through the gear transmission, and drove the feeding mechanism and the slag discharge mechanism through the chain transmission. The first pair of rollers were analyzed by force, and the approximate diameter range of bananas that can enter the squeeze mechanism was obtained. Combined with the design of the roller pattern, the feeding was smooth. The mechanical analysis of the roller squeeze mechanism was carried out, and the theoretical formula of the pressure of the roller on the banana stem was obtained. It was concluded that under the condition of the characteristics of the raw material of the banana stem, the equipment parameters and the feeding meshing angle, the smaller the gap of the roller, the greater the pressure, which provided a reference for the adjustment of the gap of the roller in the squeeze dehydration test. The ANSYS/LS-DYNA module was used to analyze the squeeze dehydration of the banana stem. The banana stem was deformed by passing through each level of the roller to verify the feasibility of the squeeze dehydration of the squeeze mechanism. The simulation value and the theoretical value of the pressure of the roller on the banana were compared to verify the reliability of the squeeze dehydration of the squeeze mechanism. The relationship between the pressure and the gap of the roller was verified by the response surface design. Finally, the squeeze dehydration test was carried out on the banana stem roller squeeze dehydrator. The test results show that the squeeze dehydration rate of the banana stem is about 28.00%-46.29%, and in the case of feeding and no blockage, the larger the diameter of the banana stem, the smaller the gap of the fourth level of the roller, the higher the dehydration rate of the banana stem. The designed squeeze dehydrator greatly reduced the volume and weight of banana stems, reduced the labor intensity and transportation costs of banana farmers, and facilitated the subsequent high-value utilization of banana stem waste.The research can provide theoretical reference and practical reference for the design and development of whole stem press dewatering equipment of banana.