Maki K. Rashid

Configuration Design and Intelligent Stepping of a Spherical Motor in Robotic Joint

Reducing the number of joints in robotic arms can save both space and number of actuators. Incubation of spherical joint carrying inserted permanent magnets on its surface by a semi-spherical stator implanted with electromagnets can provide such advantages. The developed forces between the permanent magnets arranged on the rotor surface (rotor poles) and the activated electromagnets inside the stator can produce the required torque for joint motion. Such arrangements are called spherical stepper motors (SSM). This work presents a modeling and configuration design for such joints. An intelligent scheme is developed for activating the appropriate pairs of electromagnetic stator poles to achieve the targeted motion. In addition, an algorithm is built for obtaining numbers, positions and an effective arrangement of rotor and stator poles. Reaching acceptable arrangements can produce wider motion range in different directions. Dimensionless charts for electromagnetic forces are created using the FEM. These charts are used in investigating a single step motion using a simple fuzzy scheme.

Simulation of intelligent single wheel mobile robot

Stabilization of a single wheel mobile robot attracted researcher attentions in robotic area. However, the budget requirements for building experimental setups capable in investigating isolated parameters and implementing others encouraged the development of new simulation methods and techniques that beat such limitations. In this work we have developed a simulation platform for testing different control tactics to stabilize a single wheel mobile robot. The graphic representation of the robot, the dynamic solution, and, the control scheme are all integrated on common computer platform using Visual Basic. Simulation indicates that we can control such robot without knowing the detail of its internal structure or dynamics behaviour just by looking at it and using manual operation tactics. Twenty five rules are extracted and implemented using Takagi-Sugenos fuzzy controller with significant achievement in controlling robot motion during the dynamic simulation. The resulted data from the successful implementation of the fuzzy model are used to utilize and train a neurofuzzy controller using ANFIS scheme to produce further improvement in robot performance

Smart actuator stiffness and switching frequency in suppression of vibration of a cutting tool

Techniques for suppression of vibration in cutting tools can save old machines and enhance design flexibility in new manufacturing systems. Structural stiffness interaction, with the use of smart materials, in an intelligent toolpost is investigated using the finite element method. The results proved the limited use of lumped modeling in driving conclusions and developing a toolpost system for dynamic response control. A transient solution is obtained for the toolpost response in which a smart material actuator is excited using pulse width modulation (PWM) for voltage generation to counteract the radial disturbing cutting force. Calculations showed that error elimination and transient response control require a minimum number of PWM cycles in each force period. Time delay between the actuation force and voltage has an adverse effect on error elimination, if it exceeds a certain limit. Increasing damping within a reasonable range might not eliminate the transient response originated by the voltage switching of the smart material actuator. The estimated static voltage in error elimination cannot necessarily be used in dynamic switching. The tool bit to actuator stiffness and tool carrier (holder) to actuator stiffness ratios are both preferred to be above ten when space and weight limitations do not exist.

Fuzzy algorithm and structural stiffness in error attenuation of intelligent toolpost

Vibration suppressions techniques in cutting tools can save old machines and enhance design flexibility in new manufacturing systems. The finite element method is employed to investigate structural stiffness, damping, and switching methodology under the use of smart material in tool error attenuation. This work discusses the limitations of using lumped mass modeling in toolpost dynamic control. Transient solution for tool tip displacement is obtained when pulse width modulation (PWM) is used for smart material activation during the compensation of the radial disturbing cutting forces. Accordingly a Fuzzy algorithm is developed to control actuator voltage level toward improved dynamic performance. The required minimum number of PWM cycles in each disturbing force period is investigated to diminish tool error. Time delay of applied voltage during error attenuation is also evaluated. Toolpost static force–displacement diagram as required to predict voltage intensities for error reduction is tested under different dynamic operating conditions.

Probabilistic Models for Assessing the Impact of Salinization and Chemical Pollutants

Development and rapid population growth have impacted Oman’s water resources significantly. Increasing the degradation of groundwater quality by salinization and chemical contaminants threaten pri mary sources of drinking water, especiall y in the coastal agricultura l areas. Hence, there is a substantial demand in the country for water conservation technology. This work elaborates the quality deterioration of groundwater due to chemical contaminants, which are the pri me environmental issue of the Salalah region to the south of Oman. First, we describe the develop ment and application of Dynamic Bayesian Networks (DBNs) combine with a preprocessing Bayesian technique to deter mine the impact of these contaminants on groundwater quality. These paradigm address the probabilisti c and dynamic characteristics that are significant in the understanding of pollution generation from various information sources, but in a fashion which manages the uncertainties in these sources. Second, we discuss and compare the results produced by these methods with that produced by the application of classical ti me series models.

Automating error attenuation of cutting tools using smart material

Vibration attenuation techniques in cutting tools can save old machines and enhance design flexibility in new manufacturing systems. The finite element method is employed to investigate structural stiffness, damping, and switching methodology under the use of smart material in tool error attenuation. This work discusses the limitations of using lumped mass modeling in toolpost dynamic control. Transient solution for tool tip displacement is obtained when pulse width modulation (PWM) is used for smart material activation during the compensation of the radial disturbing cutting forces. Accordingly a Fuzzy algorithm is developed to control actuator voltage level toward improved dynamic performance. The required minimum number of PWM cycles in each disturbing force period is investigated to diminish tool error. Time delay of applied voltage during error attenuation is also evaluated. Toolpost static force-displacement diagram as required to predict voltage intensities for error reduction is tested under different dynamic operating conditions.Copyright