Design and Calibration of a 3D High-Resolution Surface Profiling System Using Photometric Stereo

This paper presents the design and calibration of a 3D high-resolution surface profiling system using photometric stereo (PS). This system is mainly composed of a high resolution DSLR camera with a macro lens facing perpendicularly to the target surface, and several LEDs tilting towards the surface constrained by a light fixture. With each LED turned on at a time to create one lighting direction, the camera fixed at the same position captures an image. PS with surface normal integration (SNI) are then performed to reconstruct the surface in 3D. Methods of four calibrations for the developed system are proposed to achieve better accuracy, which are the camera radiometric calibration, the camera geometric calibration, the light direction calibration and the light intensity calibration. Experiments have demonstrated that the developed system with the calibration processes could achieve the accuracy in the order of 10 microns.

An Interactive Virtual Environment for Programming Modular Robots

The design of RoboSim, a virtual environment for modular robots which controls simulated robots with code written for the hardware robots without modification, is described in detail in this paper along with its applications in educational environments. RoboSim integrates into the Ch programming environment, a C/C++ interpreter, that provides the ability to remotely control robots through interpreted C/C++ code allowing users to alternate between hardware and virtual robots without modifying the code. Open source software projects Open Dynamics Engine, OpenSceneGraph, and Qt are employed to produce the virtual environment and user interface which provide the capability of running on all major software platforms. The design of the software includes multiple library modules each specific to a particular task; therefore the simulation library and Graphical User Interface (GUI) can link against only the necessary libraries. The GUI links against the graphical library and XML library to give an interactive view of the RoboSim Scene as users are adding robots and obstacles into both the GUI and simulation. Execution of Ch code generates a new RoboSim Scene window which has the entire simulation that utilizes the simulation, graphical, xml, and callback libraries, in addition to the identical Scene from the GUI. It generates its own window for the user to view and interact with the progress of the simulation.

A New Fractional Order Dynamic Model for Human Crowd Stampede System

Tragedies due to people’s crushing or trampling have been observed in recent years. In order to understand the reasons that lead to these accidents, a lot of research has been conducted in modeling or predicting the behavior of crowd pedestrians. A new kind of fractional order dynamic description for crowd-pedestrian system has been developed in microscopic scale in this paper for a better understanding of human collective behavior where fractional order in time domain has been introduced. Due to the freedom provided by Fractional Calculus, a lot of characters of pedestrians can be considered in this fractional order modeling framework, such as memory effects, long range interactions and heterogeneity of each individual. Simulations results using Matlab in microscopic are also presented to show the effects of integer order and fractional order on evacuation time which is useful in evaluating the evacuation process or predicting crowd stampede that is going to occur.

Maximum Power Point Tracking of Proton Exchange Membrane Fuel Cell With Fractional Order Filter and Extremum Seeking Control

Proton Exchange Membrane FC (PEMFC) is widely recognized as a potentially renewable and green energy source based on hydrogen. Maximum power point tracking (MPPT) is one of the most important working conditions to be considered. In order to improve the searching performance such as convergence and robustness under disturbance and uncertainty, a kind of fractional order low pass filter (FOLPF) is applied for the MPPT controller design based on general Extremum Seeking Control (ESC). The controller is designed with FOLPF and high pass filter (HPF) substituting the normal LPF and HPF in the original ESC design. With this FOLPF ESC, better convergence and smooth performance is gained while maintaining the robust specifications. Simulation results are included to validate the proposed new FOLPF ESC scheme under disturbance and comparisons between FOLPF ESC and general ESC method are also provided.

Development of Advanced CNC Interpolation Algorithm With Consideration of Command and Dynamic Errors

In this paper, an integrated acceleration/deceleration with dynamics interpolation scheme is proposed to confine the maximum contour error at the junction of linear junction. The dynamic contour error equation is derived analytically and then it is utilized for the interpolation design. Based on the derived formulations which could predict the command and dynamic errors, the advanced interpolation design could adjust the connecting velocity of the two blocks to confine the overall contour errors under the given tolerance. Simulation results validate the proposed algorithm can achieve higher accurate trajectory as compared to the other interpolation algorithm proposed in the past.

Gesture Based Control of a Simulated Robot Manipulator

The number of industrial and household robots is fast increasing. A simpler human-robot interaction is preferred in household robotic applications as well as in hazardous environments. Gesture based control of robots is a step in this direction. In this work, a virtual model of a 3-DOF robotic manipulator is developed using V-Realm Builder in MATLAB and the mathematical models of forward and inverse kinematics of the manipulator are coded in MATLAB/Simulink software. Human hand gestures are captured using a smartphone with accelerometer and orientation sensors. A wireless interface is provided for transferring smartphone sensory data to a laptop running MATLAB/Simulink software. The hand gestures are used as reference signal for moving the wrist of the robot. A user interface shows the instantaneous joint angles of robot manipulator and spatial coordinates of robot wrist. This simple yet effective tool aids in learning a number of aspects of robotics and mechatronics. The animated graphical model of the manipulator provides a better understanding of forward and inverse kinematics of robot manipulator. The robot control using hand gestures generates curiosity in student about interfacing of hardware with computer. It may also stimulate new ideas in students to develop virtual learning tools.

Innovative AF VCM Actuator for Smart Phone Camera Module

In the present study, we propose an innovative autofocusing (AF) voice coil motor (VCM) actuator to replace the traditional AF VCM actuators with springs for smart phone camera modules. In the proposed electromagnetic structure, the magnetic pre-compression force between the two guide rods and permanent magnet is used to replace the restoring resilience force of the two springs in the traditional AF VCM actuators. The proposed AF VCM actuator is characterized numerically using the simulation analysis of commercial software Infolytica MagNet and then verified experimentally using a laboratory-built prototype. The experimental results presented in this study show compared to traditional AF VCM actuator, the proposed AF VCM actuator has excellent AF performance to be able to replace the traditional AF VCM actuators. As a result, the proposed device provides a promising solution for smart phone camera modules or industrial applications.

Maneuvering Car Tracking Using the Interacting Multiple Model and the Dynamic 2nd-Order SVSF Method

Car tracking algorithms have recently found a major role in intelligent automotive applications. They are mainly based on the state estimation techniques to solve the maneuvering car tracking problems. The dynamic 2nd-order SVSF method is a novel robust state estimation method that is based on the variable structure control theory. It benefits from the accuracy, robustness, and chattering suppression properties of second-order sliding mode systems for robust state estimation. The main contribution of this paper is to present and implement a new tracking strategy that is a combination of the dynamic 2nd-order SVSF with the IMM filter. It benefits from the robust performance of the dynamic 2nd-order SVSF and the switching property of the IMM filter. This strategy is simulated and examined under several car driving patterns and experimental position data that are captured by a GPS device. The robustness and efficiency of this strategy is then compared with the Kalman filter-based counterparts.

A Gripper for Handling Large Leather Plies Stacked on Beams

The paper presents the preliminary design of a novel gripper able to grasp large non-rigid materials that has been conceived to face the challenge of automatic handling tasks in the leather industry. The design has been driven by the requirements to limit production costs and the complexity of the grasping device. A statistical analysis of the different templates sizes has allowed to identify a fixed configuration of the gripping points able to properly pick all the sheets within a great confidence interval. According to the varying shape of the leather templates themselves, that is due to their stacking in plies on the beam, the trajectory of the gripping points has been studied and arranged. Due to the irregular shape of the large sheets that are handled, the edges of the non-rigid materials out of the gripping area might flutter during the transferring phase: a four-bar linkage has been specifically designed, so that the motion of its end-effector prevents unwanted leather creases.

Software Based Methods to Harden Embedded Software at Run-Time: A Survey

Embedded Systems software reliability is increasingly important, therefore methods to harden existing software are needed. In general, hardening software against various failures is a necessity in modern computer systems. A lot of work has been published regarding many possible ways to achieve this non-functional requirement. Relevant topics include, e.g., test procedures, recommended development flows, and hardware measures like watchdog timers. One of these methods seems very promising to be software implemented in modern embedded systems: Control Flow Checking by signatures. Various authors have shown the effectiveness and feasibility of Control Flow Checking (CFC) by signatures for personal computer software. For instance it has been shown for standard computer-systems, that CFC is capable of reducing undetected control flow errors by at least one magnitude. This survey will focus on the applicability of such software hardening methods to embedded systems, while adhering mainly to software based approaches. Published methods will be summarized and compared. Furthermore methods to simplify derived control-flow graphs to essential states will be emphasized. Finally the possibility to apply run-time verification to the Control-flow Checking Software is considered.