Automated Surface Defect Detection using Area Scan Camera

This research comprises the design and fabrication of an automated surface defect detection system in which the defected part is automatically rejected. A special purpose rejection mechanism is designed in a manner to whether accept the defect free parts or reject the defected parts. The inspection vision system adopted in the design is an area scan camera, which works in conjunction with the MATLAB image acquisition tool. The control process is achieved via a PIC16F84A microcontroller, where it controls the image capturing and the defected part rejection mechanism. To validate the performance of this designed system, three types of plates were used, namely, defect free, punch defected and crack defected. Results showed that all the defected plates were rejected thus insuring the high efficiency of the system. Keywords: area scan camera, inspection vision system, surface detectio

Motion Control of an Underactuated 2-DOF Robotic Manipulator

This paper deals with the motion control of the end effector of a 2-DOF linkage type underactuated robotic manipulator. A simulation procedure is implemented for the motion control in which actuation and braking actions were applied on the two joints of the manipulator subsequently,  hence moving the end effector in a point to point manner through the desired path. From the results obtained, it was found that the percentage error in trajectory mainly does not exceed (1%). In some specific points on the trajectory, error reached its maximum value which was found to be (3.64%). In general, these error values are almost acceptable, although an effort will be achieved in future work to reduce this error and improve the design. Keywords: Underactuated Manipulators, Motion Control, Simulation

Grasping Force Prediction for Underactuated Multi-Fingered Hand by Using Artificial Neural Network

In this paper, the feedforward neural network with Levenberg-Marquardt backpropagation training algorithm is used to predict the grasping forces according to the multisensory signals as training samples for specific design of underactuated multifingered hand to avoid the complexity of calculating the inverse kinematics which is appeared through the dynamic modeling of the robotic hand and preparing this network to be used as part of a control system.Keywords: Grasping force, underactuated, prediction, Neural networ

Optimization and Analysis of Underactuated Linkage Robotic Finger

In this study it is required to maximize the transmission performance, which is leading to increase the transmitted torque from the actuated joints to the underactuated joints through transmission mechanism. Accordingly grasping forces in finger phalanges will increase. Studying the four bar mechanism parameters of a specific configuration within defined limits led to the linkage transmission defect parameter, which play a major role in deciding the linkage performance, used as optimization objective function to be minimized. This study presents an optimization procedure carried out using matlab fminunc function, formulated by using Freudenstein's equations to be applied on a (Cassino-Underactuated-Multifinger-Hand) design , using  one finger and a thumb .A mathematical model of grasping forces of the finger were introduced taking into account the solid links in the( Ca.U.M.Ha)  robotic finger . Keywords: Linkage , underactuated, optimizatio

A Review of Lower Limb Exoskeletons

In general, exoskeletons are defined as wearable robotic mechanisms for providing mobility. In the last six decades, many research work have been achieved to enhance the performance of exoskeletons thus developing them to nearly commercialized products. In this paper, a review is made for the lower limb exoskeleton concerning history, classification, selection and development, also a discussion for the most important aspects of comparison between different designs is presented. Further, some concluding remarks are withdrawn which could be useful for future work. Keywords: Exoskeletons, Lower extremity exoskeleton, Wearable robot

Contact mechanics for soft robotic fingers: modeling and experimentation

Human fingers possess mechanical characteristics, which enable them to manipulate objects. In robotics, the study of soft fingertip materials for manipulation has been going on for a while; however, almost all previous researches have been carried on hemispherical shapes whereas this study concentrates on the use of hemicylindrical shapes. These shapes were found to be more resistant to elastic deformations for the same materials. The purpose of this work is to generate a modified nonlinear contact-mechanics theory for modeling soft fingertips, which is proposed as a power-law equation. The contact area of a hemicylindrical soft fingertip is proportional to the normal force raised to the power of γcy, which ranges from 0 to 1/2. Subsuming the Timoshenko and Goodier (S. P. Timoshenko and J. N. Goodier, Theory of Elasticity, 3rd ed. (McGraw-Hill, New York, 1970) pp. 414-420) linear contact theory for cylinders confirms the proposed power equation. We applied a weighted least-squares curve fitting to analyze the experimental data for different types of silicone (RTV 23, RTV 1701, and RTV 240). Our experimental results supported the proposed theoretical prediction. Results for human fingers and hemispherical soft fingers were also compare

Position Control of Linkage Underactuated Robotic Hand

In this study a proposed PID control system for (Ca.U.M.Ha) robotic hand with a finger and a thumb introduced, to control grasping cylindrical objects made from different materials soft and hard within a range of (48-150) mm in diameter . A samples of PID response figures for object that need just a finger, and object that needs a finger with a thumb introduced in additional to the figures of actuators voltage needed for both cases through grasping. Keywords: Linkage , underactuated, position  PID contro

Static and Dynamic Calibration for FlexiForce Sensor Using a Special Purpose Apparatus

This paper introduces an experimental apparatus to be implemented for calibrating the FlexiForce sensor both statically and dynamically. This sensor uses a resistive – based technology and it has force range of (0-111N). The static calibration is done with static weights under static conditions, also these sensors are calibrated dynamically with the use of an inertial force of a mass as the known dynamic force; the acceleration of the mass is measured by an accelerometer board attached to the oscillating mass. These sensors are calibrated with the same conditions under which force sensors are supposed to be used, as to measure the force on the fingertip of a robotic manipulator. Results of both calibration methods are presented and discussed herewith. Keywords: Force sensors, dynamic calibration, special apparatu

Deflection Analysis of an Elastic Single Link Robotic Manipulator

Robotics manipulators with structural flexibility provide an attractive alternative to rigid robotics manipulators for many of the new and evolving applications in robotics. In certain applications their use is unavoidable. The increased complexity in modeling and control of such manipulators is offset by desirable performance enhancements in some respects. In this paperthe single- link flexible robotics manipulator was designed and implemented from Perspex and designed with 0.5 m length , 0.02 m width and with 0.004 m thickness with mass located at the tip. There are four subsystems; motion, control, accelerometer and gyro and a host computer subsystem. The work principle of single-link robotics manipulator is the base servomotor. It rotates a hub with the link on it and measure the tip deflection. the deflection was measured for three cases without load, with 27.5 and with 59.4 gram at the end of the flexible link . During each of the above cases I rotated the base servo motor at an angular velocity equals to 90 deg./s using control card based on ATMEGA640 microcontroller. the deflection was measured for the three cases and the deflection measured by MMA7631 Accelerometer and Gyro . This accelerometer controlled by using MEGA Arduino board . Then the dataI collected collected from accelerometer and plot it using MATLAB software and compared between theoretical results obtained from MATLAB program that based on Lagrange equation of motion and experimental results and we found the maximum deflection occurred when V=180 deg/sec and tip load=59.5 gram

Simulation Analysis of Grasping Forces for a 3-DOF Robotic Manipulator

In this paper, an attempt is made to simulate the grasping process of an underactuated robotic manipulator. A mathematical model of grasping forces of the manipulator was introduced, then a simulation model was built using MSC. Visual Nastran software. In order to validate the simulation model, different locations of the grasped object were considered. Contact forces were calculated theoretically and obtained from simulation of each grasped object location. Results obtained for each case are in good agreement, thus validating the simulation procedure followed in this study. Keywords: Underactuated manipulator, Grasping force, Simulation analysi