During the process of photosynthesis, the plant will emit fluorescent light as a source of energy dissipation. Through Fluorescence imaging, we can capture the intensity of the fluorescence emitting from the plant and use this data to predict the efficiency of the photosynthesis within the plant, which is directly related to the amount of water the plant can absorb. Therefore, we can utilize this information to learn about if the plant is having water stress or not.

Robotic arm design

The robotic arm have to be agile enough to capture the image of a leaf while avoiding other leaves and branches. Since the robotic arm will combine with a mobile robot in the end to autonomously detect all of the plants in a greenhouse, we have an extra degree of freedom from the mobile robot. Therefore, I designed the robotic arm to have 5 degree of freedom (DoF). After I've drawn the prototype of the arm, I analyzed how much torque is required for each joint to decide the specifications for the motors. Calculated from the end effector to the base joint, the calculations can be seen below.

To maintain a smooth movement and high precision while having relatively low cost, I decided to use DC brushed servo motors. The details for the motors can be seen in the following table.