Industrial Robotic Arm for Chilli Milling Process

Chilli (Capsicum annuum), one of the essential ingredients in Sri Lankan cuisine, is widely cultivated for producing dried chilli. The narrow conical-shaped chilli pods with wrinkled surface do not support much of the existing common mechanical feeding systems such as augers or bucket conveyorsin the chilli processing plants. Therefore, the objective of this study is to design and develop a robotic arm with a proper grabbing technique to feed chilli into the grinding mill. Furthermore, it is intended to install the developed robotic arm in an industrial level processing plant to test the feasibility of theindustrial application. The industrial robot designed in this study is primarily composed of three parts: the base, the arm and the wrist. These components connect with joints to form a unit. At the end of the wrist, an end-effector, which is a gripper for grasping chilli pods, is located.ATmega328 microcontroller, micro switches and DC motors were used to operate the robotic arm. The feeding rate is automatically controlled using a Hall Effect sensor. The robotic arm grabber was placed on top of the chilli containing trough (2.5m wide, 10.5m long, and 1.25m high) of an industrial level chilli processing plant.When operating, the grabber could grab 1.640±0.128 kg of chilli from the bulk in a single operation. The average time taken for one complete cycle of grabbing chilli, lifting the grabber, turning the arm on to the conveyer and releasing chilli on to the belt conveyor, varies from 20 s and 30 s depending on the height of chilli in the trough. The feeding rate varies from 440.6 kg/h and 218.66 kg/h when chilli is grabbed from the top and the bottom layers respectively. Therefore, this system can be recommended for maximum feeding rate of chilli up to 218.66 kg/h. Capacity can be increased by adding the same mechanism parallel or scaling up the existing system.