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Implementation and Development of an Adaptive Steering-Control System

In this paper, an adaptive steering-control system for a steer-by-wire system, which consists of a vehicle directional-control unit and a driver-interaction unit, is developed. The adaptive online estimation method is used to identify the dynamic parameters of the vehicle directional-control and driver-interaction units. A nonlinear 4-degree-of-freedom (DOF) vehicle model, including the longitudinal, lateral, yaw, and quasi-static roll motions, is derived using Newtonian mechanics to simulate and test the adaptive steering-control system. Experimental results are performed to demonstrate the efficacy of the proposed adaptive steering-control system.

Acoustic Properties of Tea-Leaf Fiber Mixed Polyurethane Composites

Natural tea-leaf fibers were used as reinforcement agents in different polyurethane-based matrixes to improve the sound absorption properties of the composite. Adding tea-leaf-fibers to rigid polyurethane foam demonstrate limited contribution to sound absorption properties of the material. Furthermore, adding tea-leaf-fibers to soft foam results in a significant improvement of sound absorption properties of the composite. In this study herein, the composite including 24% tea-leaf-fibers was observed to provide the best sound absorption coefficient. Additionally, soft foam demonstrates better acoustic properties than rigid foam.

Compliant control of steer-by-wire systems

Vehicle directional control and driver interaction assemblies have been built to study and implement impedance control strategies on a steer-by-wire system. Adaptive on-line estimation is used to identify the dynamic parameters of vehicle directional control and driver interaction assemblies. A nonlinear 4 DOF vehicle model, including longitudinal, lateral, yaw and quasi-static roll motions is derived using Newtonian mechanics to simulate and test the impedance control strategies developed. Impedance control strategy is used to control the dynamic characteristics of the steering system for improving the steering-feel and vehicle stability.

Evaluation of Sound Absorption, Printability, and Some Mechanical Properties of Thin Recycled Cellulosic Sheets Containing Wool, Ceramic Fiber, and Cotton Dust

A number of thin biocomposites were produced from waste corrugated board pulp with 15% and 30% blending of wool fibers (WF), ceramic fibers (CF), and cotton dust (CD), respectively. The highest sound absorption value was obtained from samples containing 30% wool fibers. Printability of control sheets unfortunately was remarkably damaged. Ceramic fibers improved the thermal stability of control sheets, which was followed by WF and CD. Tensile and burst indexes of samples, however, were greatly reduced. It was furthermore found that CD, CF, and WF additions increased the air permeability values of resultant papers parallel to great reduction on densities.

Robot positioning of flexible-link manipulator using vision

Vision-aided flexible link robot positoning using the Camera Space Manipulation (CSM) method is developed. The primary motivation for this work is to use an autonomous vision-aided robotic system to pick-up and accurately move a flexible object that it encounters. The work consists of analytical and experimental investigation of the performance of CSM for a kinematic model of the PUMA manipulator with a flexible structure at the wrist which accounts for the gravitation. Trade-offs between camera view parameters and axial deflection model parameters were investigated. View parameter reestimation and maneuvering resulted a very accurate placement of the end-effector at the target.

Acoustic Properties of Waste Particle Mixed Polyurethane Composites

A variety of particles were mixed with polyurethane-based matrix to develop functional composites. Adding marble, steel, prina (olive oil extraction) and sand particles into PU foam increases sound absorption characteristics of the material. Best results were obtained with marble and steel particles. Marble particles improved high frequency characteristics better than steel particles. Increasing the amount of prina particles enhanced mid-to-high frequency sound absorption properties. Acoustic properties of sand mixed composites were increased to its optimal rates by adding 25% particles into the polyurethane matrix.

A device to measure joint angles and foot force for lower extremity force distribution computations

In rehabilitation of walking difficulties, it is vital to be aware of the distribution of the force and moment pairs faced by the lower limb extremities. The mathematical equations for numerical computation of these pairs are provided by free body diagrams that require some foot force measurements and joint/segment-tilt angle measurements as well. In this study, a device has been developed to capture the foot force and the ankle, knee and hip joint angles. The device is equipped with three accelerometers and six force sensitive resistors. The measured forces and angles are computed and next transferred to personal computer. The device is calibrated and then tested on a healthy volunteer. The test results show that the device may be used to provide valuable measurements to compute force distributions in lower extremity.

Electronic Spectra and High-Resolution B-type Delayed Fluorescence of Salicylidene-m-bromo-aniline in Hexane

ABSTRACT The observation of triplet--triplet absorption and emissions of salicylidene-m-bromo-aniline is complicated by possible colored isomer formation during the optical pumping. The short-lived (singlet--singlet) and long-lived (triplet--triplet) absorption spectra were recorded photographically by microsecond flash and nanosecond laser flash photolysis techniques. Salicylidene--aniline complexes were purified by repeated recrystallization until further recrystallization produced no further changes for X-ray diffraction pattern and optical absorption emission properties. B-type delayed fluorescence, T-T absorption, color isomer absorption, and T-T emissions of this compound were recorded for the first time.

Desensitization of Camera-Aided Manipulation to Target Specification Errors

Applications of vision-based remotely operated robotic systems range from planetary exploration to hazardous waste remediation. For space applications, where communication time lags are large, the target selection and robot positioning tasks may be performed sequentially, differing from conventional telerobotic maneuvers. For these point-and-move systems, the desired target must be defined in the image plane of the cameras either by an operator or through image processing software. Ambiguity of the target specification will naturally lead to end-effector positioning errors. In this paper, the target specification error covariance is shown to transform linearly to the end-effector positioning error. In addition, a methodology for optimal estimation of camera-view parameters of a vision-based robotic system based on target specification errors is presented. The proposed strategy is based on minimizing the end-effector error covariance matrix. Experimental results are presented demonstrating an increase in end-effector positioning, compared to traditional view parameter estimation by up to 32.