ANN Control Based on Patterns Recognition for A Robotic Hand Under Different Load Conditions

في هذا البحث, الشبكة العصبية الاصطناعية (ANN) قد تم تدريبها على انماط نسب المركبات العمودية الى الافقية لقوى التماس عند وقت حدوث الانزلاق, لتكون قادرة على تمييز الانزلاق تحت انواع مختلفة من الأحمال (الحمل الستاتيكي والحمل الديناميكي), ومن ثم توليد اشارة راجعة تستخدم كمشغل لمحرك اليد الصناعية. هذه العملية اجريت بدون الحاجة لأي معلومات حول خواص الجسم الممسوك, مثل الوزن, تركيب السطح, الشكل, معامل الاحتكاك و نوع الحمل المؤثر على الجسم الممسوك. لتحقيق ذلك , تم اقتراح تصميم جديد لرأس الاصبع من اجل كشف الانزلاق في اتجاهات متعددة بين الجسم الممسوك ورؤس الاصابع الاصطناعية. هذا التصميم يتألف من اصبعين مع نظام تشغيل يتضمن اجزاء مرنة (نوابض انضغاطية). هذه النوابض تعمل كمعوض لقوة المسك عند وقت حدوث الانزلاق حتى في وضعية التوقف لمحرك اليد. نسب مركبات قوى التماس يمكن حسابها بواسطة حساسات قوى تقليدية (FlexiForce sensor) بعد معالجة بيانات القوى باستخدام برنامج Matlab/Simulink ومن خلال علاقات رياضية معينة التي تم اشتقاقها لوصف الآلية الميكانيكية للإصبع الاصطناعي.In this paper, the Artificial Neural Network (ANN) is trained on the patterns of the normal component to tangential component ratios at the time of slippage occurrence, so that it can be able to distinguish the slippage occurrence under different type of load (quasi-static and dynamic loads), and then generates a feedback signal used as an input signal to run the actuator. This process is executed without the need for any information about the characteristics of the grasped object, such as weight, surface texture, shape, coefficient of the friction and the type of the load exerted on the grasped object. For fulfillment this approach, a new fingertip design has been proposed in order to detect the slippage in multi-direction between the grasped object and the artificial fingertips. This design is composed of two under-actuated fingers with an actuation system which includes flexible parts (compressive springs). These springs operate as a compensator for the grasping force at the time of slippage occurrence in spite of the actuator is in stopped situation. The contact force component ratios can be calculated via a conventional sensor (Flexiforce sensor) after processed the force data using Matlab/Simulink program through a specific mathematical model which is derived according to the mechanism of the artificial finger

Real-Time Vibration Control of Rotor-Bearing System Based on Artificial Neural Networks and Active Support Stiffness

A real-time dynamic response of the rotor-bearing system is controlled through an active support stiffness designed and constructed for this purpose. It consists mainly of a variable, flexible beam length. A stepper motor with a screw is implemented to manipulate the beam length to the required optimum position. Hence, it works as active spring stiffness, which minimizes the vibration response for the system. Stiff support is fixed at a specified position on the beam, and it is provided with a small ball bearing at the point of contact with the rotor at the other end. An artificial neural network has been used to control the dynamic system response. Response simulation with real-time LabVIEW is conducted to play a role as an interface to deal with the required sensors' records and the rotation of the stepper motor. The results show that the controlled system is efficient in obtaining the optimum support stiffness for different rotational speeds of the driven motor, which gives, in turn, the optimum system dynamic response

Determination of Natural Frequency and Critical Velocity of Inclined Pipe Conveying Fluid under Thermal Effect by Using Integral Transform Technique

This study proposes an analytical solution of natural frequencies for an inclined fixed supported Euler-Bernoulli pipe containing the flowing fluid subjected to thermal loads. The integral transform technique is employed to obtain the spatial displacement-time domain response of the pipe-fluid system. Then, a closed-form analytical expression is presented. The effects of various geometric and system parameters on the vibration characteristics of pipe-fluid system with different flow velocities are discussed. The results illustrate that the proposed analytical solution agrees with the solutions achieved in previous works. The proposed model predicts that the pipe loses the stability by divergence with the increasing flow velocity. It is evident that the influences of inclination angle and temperature variation are dramatically increased at a higher aspect ratio. Additionally, it is demonstrated that the temperature variation becomes a more harmful effect than the internal fluid velocity on the stability of the pipe at elevated temperature

The Effect of Soil Content, Drilling Parameters and Drilling Tool Diameter on the Vibration Assessment in the Drilling Rig

This paper represents a study of the effect of the soil type, the drilling parameters and the drilling tool properties on the dynamic vibrational behavior of the drilling rig and its assessment in the drilling system. So first, an experimental drilling rig was designed and constructed to embrace the numerical work. The experimental work included implementation of the drill-string in different types of soil with different properties according to the difference in the grains size, at different rotational speeds (RPM), and different weights on bit (WOB) (Thrust force), in a way that allows establishing the charts that correlate the vibration acceleration, the rate of penetration (ROP), and the power consumption curves with the depth of drilling. In addition to that the ANSYS Workbench (the 14.0 release) software was used to simulate and verify the experimental results. And it was also used to model other numerical cases with different drill bit diameters