Furqan Ullah

Real-time object following fuzzy controller for a mobile robot

This paper presents an object following wheeled mobile robot in which fuzzy logic controller is utilized to handle uncertain input data from three ultrasonic sensors. A maintenance system selects behaviour from the range data at each step so that the mobile robot can move behind the object by keeping the distance constant. The proposed model is attested in an environment containing moving objects. The experimental and simulation outcomes indicate better adaptability, attain the desired turn angle precisely, and adopt the same speed as that of the followed object.

Integrated collision avoidance and tracking system for mobile robot

In the intelligent transportation system, various accident avoidance techniques have been applied. Among them, one of the most common issues is the collision, which is yet unsolved problem. To this end, we develop collision warning and avoidance system (CWAS), which is implemented in the wheeled mobile robot. Likewise, path planning is a crucial problem in the mobile robots to perform a given task correctly. Here, a tracking system is presented for the mobile robot, which follows an object. Thus, we have implemented an integrated CWAS and tracking system in the mobile robot. Both systems can be activated independently. In the CWAS, the robot is controlled through a remotely controlled device, and collision prediction and avoidance functions are performed. In the tracking system, the robot performs tasks autonomously, where the robot maintains a constant distance from the followed object. The surrounding information is obtained through the range sensors, and the control functions are performed through the microcontroller. The front, left, and right sensors are activated to track the object, and all the sensors are used for the CWAS. Two algorithms based on the sensory information are developed with the distance control approach. The proposed system is tested using the binary logic controller and the fuzzy logic controller (FLC). The comparison of both controllers is also described by preferring time delay and complexity. The efficiency of the robot is improved by increasing smoothness in motion using the FLC, achieving accuracy in tracking, and advancements in the CWAS. Finally, simulation and experimental outcomes have displayed the authenticity of the system.

A sensor based robotic model for vehicle collision reduction

This work presents an integrated monitoring system to avoid accidents or collisions between vehicles from both (front and back) sides. It can be used to save human lives from a number of road accidents. To demonstrate such a low cost system, a distance sensors framework, microcontroller, remotely controlled unit using radio frequency, and an alarm unit are utilized. A navigation approach of the robot is also described based on the range sensors. To verify the presented strategy, the experimental test has been carried out in a real environment by moving robot between different vehicles and objects.

Mobile robot navigation with distance control

Intelligent systems to increase the road safety have been widely applied in the automotive sector; similarly, they have critical importance in the robotics to navigate the robot safely. Automatic distance control system helps to avoid collision between vehicles. In this paper, we present an algorithm to maintain a distance between the robot and the object. It keeps the autonomous mobile robot at a safe distance from the object. It is implemented in a wheeled mobile robot to track the moving object. The surrounding information is obtained through the range sensors that are mounted at the front side of the robot. The central sensor gives instructions for the forward and backward motion, and the other sensors help for the left and right motion. To avoid collision, safety distance, which makes the movement easy in the out of range, stop, and forward and backward modes, is predefined in the mobile robot. Each time the range data is compared with the predefined distance measurements, and the respected function is activated. The robot is characterized due to low cost and simple control architecture. Different experiments were carried out in the indoor and outdoor environments with different objects. The results have shown that the robot tracks the object correctly by maintaining a constant distance from the followed object.

Development of a Real-time 3D Intraoral Scanner Based on Fringe-Projection Technique

Received 14 February 2012; received in revised form March 27 2012; accepted March 28 2012ABSTRACTReal-time three-dimensional shape measurement is becoming increasingly important in variousfields, including medical sciences, high-technology industry, and microscale measurements.However, there are not so many 3D profile tools specially designed for specifically narrowspace, for example, to scan the tooth shape of a human jaw. In this paper, a real-time 3Dintraoral scanner is proposed for the measurement of tooth profile in the mouth cavity. The pro-posed system comprises a laser diode beam, a micro charge-coupled device, a graticule, a piezo-electric transducer, a set of optical lenses, and a polhemus device sensor. The phase-shiftingtechnique is used along with an accurate calibration method for the measurement of the toothprofile. Experimental and theoretical inspection of the phase-to-coordinate relation is presented.In addition, a nonlinear system model is developed for collimating illumination that gives themore accurate mathematical representation of the system, thus improves the shape measurementaccuracy. Experiment results are presented to verify the feasibility and performance of the devel-oped system. The experimental results indicate that overall measurement error accuracy can becontrolled within 0.4 mm with a variability of ±0.01. Key Words: Calibration, Camera-laser scanner, Virtual fringe-projection setup

Visual, Haptic, and Auditory Realities Based Dental Training Simulator

This research paper presents a surface-based virtual dental sculpting simulator based on mixed auditory, visual, and tactile realities. The simulator can be used to perform different dental procedures (i.e., grinding, drilling, or surface scrubbing), and gain experience of using various virtual dental tools of different shapes. The surface-based dental model, which is extracted from a commercial 3D dental laser scanner, is used for simulating sculpting processes at less memory cost. Large amount of triangular mesh data is contained in scanned models; therefore, a model reduction algorithm is proposed for large triangular mesh data. For the computation of repulsive force feedback, a spring-damper force model with a force filter is used. Vertex deformation method is implemented along with an enhanced bi-tri subdivision method of triangles to perform precision sculpting simulation. In order to make the mesh regular, a number of mesh refinement algorithms are performed. Finally, considering the fidelity, stability, computer efficiency, and update rate of the haptic display, it can be concluded that these mixed realities based virtual system can generate stable simulation of material removal from a human tooth model with realistic auditory, visual, and force sensations.

Piezoelectric Transducer Based 3D Intraoral Scanner

There are not so many 3D profile tools specially designed for specifically narrow space, for example, to scan the tooth shape of a human jaw. In this paper, a real-time 3D intraoral scanner based on piezoelectric transducer is presented for the measurement of tooth profile in the mouth cavity. The proposed system comprises a laser diode beam, a micro charge-coupled device, a graticule, a piezoelectric transducer, a set of optical lenses, and a Polhemus device sensor. The phase-shifting technique is used along with an accurate calibration method for the measurement of the tooth profile. Experimental and theoretical inspection of the phase-to-height relation is described. Simulation and optical measurement results are presented to verify the feasibility and performance of the developed system.

Analysis and Performance Comparison of 3D Measurement Systems Based on Fringe Projection Profilometry

In this paper, four models of 3D measurement systems are evaluated based on collimating and perspective projections using a real-time 3D virtual scanning system. Fringe projection technique is utilized due to its popularity for real-time and high resolution applications. Analysis and performance comparison of the phase-to-coordinate relation for all four models is presented. Nonlinear system models are proposed to obtain the accurate 3D shape for collimating projection models. Finally, the coordinates acquisition, reconstruction, and display processes are performed, and results are presented to verify the proposed approaches.

Development of Rafter Processing Machine and Simulation Verification

Han-ok (the Korean traditional house) is famous for its beauty and healthful aspects. However, its construction cost is too high because of the manual process of parts such as rafter, timber, etc. These days, many people want to build a modernized Korean traditional house at a low cost. In order to do so, the rafter machining process is required to be automatized using a CNC machine. It is also observed that, generally the timber does not have a uniform shape. Therefore, it is also needed to examine the timber shape before starting its processing. This paper presents the concept design of the rafter processing CNC machine, and a 3D laser scanning system. The laser scanner is developed to acquire 3D details of the timber shape. Furthermore, the results of simulated experiments are presented to investigate surface roughness during the machining process of the timber. Since cutting parameters largely influence on surface roughness and cusps formation, it is needed to achieve optimal machining parameters. Several experiments were carried out changing cutting parameters such as cutting tool diameter, feed-rate, and spindle speed.

Development of rafter processing machine for Korean traditional houses

The Korean traditional house is famous for its beauty and healthful aspects. However, its construction cost is too high because of the manual process of parts such as rafter, timber, etc. These days, many people want to build a modernized Korean traditional house at a low cost. In order to do so, the rafter machining process is required to be automatized using a CNC machine. It is also observed that, generally the timber does not have a uniform shape. Therefore, it is also needed to examine the timber shape before starting its processing. This paper presents the concept design of the rafter processing CNC machine, and a 3D laser scanning system. The laser scanner is developed for obtaining 3D details of the timber shape. Furthermore, the results of simulated experiments are presented to investigate surface roughness during the machining process of the timber. Because cutting parameters largely influence on surface roughness and cusps formation; therefore, to achieve optimal machining parameters, several experiments were carried out with small and larger cutting tool diameter, different of feed rate and spindle speed.