Egg Gripper Design
Background
Robotic grippers are widely used in automation and manufacturing to handle objects of different shapes, sizes, and materials. Designing a gripper for fragile items such as an egg requires careful control of the gripping force to avoid breaking or slipping.
This project was developed to understand how grippers work mechanically and how sensors and controllers can be used to automate their movement. The work involved designing a two-finger gripper and controlling its operation using an Arduino-based feedback system.
Objective
The main objective of this project was to design and control a robotic gripper that can safely hold an egg using the minimum force required.
The project focused on:
Designing the gripper mechanism and analysing its motion.
Performing calculations for gripping force and torque.
Developing a control system using Arduino and sensors.
Implementing a PID feedback loop to automatically adjust the motor torque based on force readings.
Design Framework
The work was carried out in two main parts:
Mechanical design of the gripper
Control system development and testing
1. Mechanical Design
Different types of grippers such as impactive, ingressive, and adhesive were studied.
An impactive two-finger gripper was chosen because it is simple and effective. It works by pinching the object from both sides and holding it through friction.
A worm and helical gear system was selected to provide smooth motion, increase torque, and ensure self-locking, so the gripper could hold the object even when the power is off.
The complete model was designed in SolidWorks 2020, and motion studies were performed to check the movement and torque transfer between gears.
Calculations were done to find the required gripping force, torque, and motor speed needed to hold an egg safely.
The 3D model was completed, but the physical model was not 3D printed in this stage. The focus was on control simulation and force regulation using Arduino.
2. Control System
A 3–6 V DC geared motor was used to operate the gripper fingers.
The motor was connected to an Arduino Uno through an L293D motor driver.
A straight bar load cell was used as a force sensor, and its output was amplified using a load cell amplifier before being sent to Arduino.
A PID (Proportional–Integral–Derivative) control algorithm was programmed in Arduino IDE.
The PID controller compared the desired gripping force (setpoint) with the actual force measured by the sensor. It then adjusted the motor speed and direction to reduce the error.
This setup created a closed-loop control system, where the motor automatically changed its motion based on real-time sensor feedback.
The system was tested successfully, showing that the motor could be controlled smoothly and maintain stable gripping force.
Summary
The gripper mechanism was fully designed and analysed using SolidWorks.
The control system was implemented using Arduino Uno, L293D driver, and load cell feedback.
The PID control loop worked effectively to regulate the force applied by the motor.
Although the gripper was not 3D printed, the control simulation demonstrated that the design could safely grip an egg and maintain the desired force.
