Haptic dokunma hisli ve kuvvet geri beslemeli arayüz sistem tasarımı

TÜBİTAK MAG01.07.2008“Haptic” cihaz, kullanıcı ile bilgisayar arasında üç boyutlu veri transferi sağlayan bir cihazdır. Bu cihaz kullanıcıya sanal ortamdaki bir nesneyi görmenin yanında, bu sanal nesneye dokunma olanağı da sağlar. Aynı zamanda bu cihaz ile gerçek bir nesneden veriler alınarak bu verilerin sanal ortamda kullanımı da gerçekleştirilebilir. Günümüzde sanal gerçeklik teknolojisinin gelişimine paralel olarak “haptic” cihazlarının kullanımı, sanayi, eğitim ve tıp alanlarında gittikçe artmaktadır. Bu teknolojinin değişik uygulama alanları, farklı bilim dallarına ait disiplinlerarası çalışmaları gerektirdiğinden, kendi içinde özgün çalışma konularını da yaratmaktadır (“haptic” arayüz tasarımı, serbest modelleme, sanal ortamda ameliyat eğitimi, vb.). Medikal uygulamalarda önemli bir potansiyele sahip bu teknoloji ile daha önceleri el işçiliği ile yapılmak zorunda kalınan karmaşık modifikasyonlar gerçekleştirilebilmektedir (beyin cerrahisinde hata kabul etmeyen, ustalık ve ameliyat öncesi uzun uğraşlar gerektiren operasyonlar). Bu örnek “haptic” cihazlar ile dijital ortamda gerçekleştirilebilecek olan uygulamalardan sadece bir tanesidir. Bu proje kapsamında, bahsedilen uygulama alanlarına yönelik 7 serbestlik dereceli bir “haptic” cihaz tasarlanıp üretilmiş ve cihazın kullanılabilirliğini göstermek için bir arayüz tasarlamıştır. Günümüze kadar tasarlanmış olan bütün “haptic” cihazlar maksimum 6 serbestlik derecesine sahiptirler. Tasarlanan 7 serbestlik dereceli “haptic” cihaz, bugüne kadar üretilmiş aynı uzuv uzunlukları ve eklem değişkenlerine sahip diğer “haptic” cihazlar ile karşılaştırıldığında yaklaşık %20 daha büyük bir çalışma hacmine ve daha esnek bir çalışma kabiliyetine sahiptir. Bu çalışma, Dünya’daki “haptic” cihazların geliştirilmesi ve Türkiye’deki “haptic” cihazların ve uygulama alanlarının yaygınlaşması açısından son derece önemlidir.Haptic devices are used to provide multi-modal data transfer between haptic users and computers in virtual reality applications. They enable humans to take force and tactile feedback from any virtual or remote objects. Haptic devices also facilitate the use of data collected from a real object in the virtual environment. Usage of the haptic devices increase more and more in industrial, educational and medical applications in parallel with development of virtual reality technology. As virtual reality technology requires interdisciplinary study with related to its application areas, it creates a lot of different specific working areas (Haptic interface design, freeform model, surgical operations in virtual environment etc.). Especially, some complex modifications which require hand-working can be performed with the system having great potential in medical applications (Brain surgery without error and operations which require great skill etc.). This is only one of the implementations of haptic devices in digital environment. Aim of this project is to design and manufacture a novel haptic device which serves the mentioned application areas and to improve an interface to implement the device. Most of the haptic devices in literature have maximum 6 DOF. The 7 DOF haptic device designed has about 20% extra working space and more flexible working capability compared to the other haptic devices with the similar link lengths and joint limitations. This project is important in terms of the development of haptic devices in the world as well as spreading of haptic devices and its applications in Turkey

End control damping algorithm for a stabilized gun turret system for the satisfaction of the collision avoidance requirement

© 2021 Elsevier B.V.This paper presents a collision avoidance algorithm for stabilized gun turrets and its real-time implementation. With the help of new collision avoidance algorithm, all types of turrets can be driven more efficiently and safely according to the specified speed, acceleration and jerk limits. Even in situations such as avoiding obstacles, deceleration/acceleration, if the user issues new commands which does not cause a collision, the algorithm starts to apply the new commands providing flexibility to the user. Since all possible worst scenarios are examined one by one, it is guaranteed that the algorithm provides collision free motion in both simulations and real-time tests. A configuration space where worst scenarios can occur is created for the performance measurement of the algorithm, and the same space is used in all tests. By giving different speed commands in the specified configuration space, the performance of the algorithm at different speeds is observed on the stabilized gun turret. For the measurement of the performance under the noisy speed commands, a custom noisy speed command of about 1000s is created and both simulation and real-time tests are performed. As a result of these tests, it is shown that there is no collision. Finally, by adding cascade position control loop, the departure from the starting point to the desired target point is achieved without any collision. The most important feature that distinguishes this algorithm from others is both speed and position can be controlled and during transition phase, the target point can be changed instantly. In addition, no target position is required for the system to move collision-free, only axis speed commands are sufficient. Since the algorithm does not intervene in the speed and torque loops in contrast to potential field-based methods, it can be added to ready-to-use systems by manipulating only the speed references

Hareket Kısıtlı Sistemlerde Viskoz ve Coulomb Sürtünme Tanılaması

Bu çalışmada hareket kısıtlamaların olduğu sistemlerde viskoz ve Coulomb sürtünmelerin tanılanması için basit ve ucuz bir yöntem geliştirilmiş ve bu yöntem bir prototip üzerinde denenmiştir. Testler sistemdeki hareket kısıtlamalarına göre farklı hızlar için oluşturulan konum profilleriyle yapılmıştır. Elde edilen verilerle negatif ve pozitif hareket yönlerinde oluşan viskoz ve Coulomb sürtünme parametreleri bulunmaktadır. Geliştirilen yöntemle sistemdeki Coulomb sürtünmenin konuma bağlı olup olmadığı ve konuma bağlı Coulomb sürtünmenin konuma göre değişimi de bulunabilmektedir. Abstract—In this study, a simple and inexpensive method is developed in order to identify viscous and Coulomb frictions in systems with motion limitations. This method is used on a prototype. A series of tests are performed using position profiles with different speeds created according to motion limits in the systems. Using the data obtained from these tests, viscous and Coulomb friction characteristics are identified for both negative and positive motion directions. The method developed can also be used to determine whether the Coulomb friction is position dependent or not and the change of Coulomb friction with the position

Elektromekanik Kontrol Tahrik Sisteminin Matematiksel Modellenmesi ve Kontrolü

Elektromekanik eyleyiciler uçak ve füzelerde olmak üzere birçok uygulamada sıklıkla kullanılmaktadır. Bu çalışma kapsamında, fırçasız doğru akım motoru, bilyalı vida ve kaldıraç mekanizmasından oluşan bir elektromekanik kontrol tahrik sistemi ele alınmıştır. Bu tip kontrol tahrik sistemlerinde, kaldıraç mekanizmasının kendisinden, limitlerden, Coulomb sürtünmelerinden, boşluklardan ve kaldıracın ilk montaj konumlanmasından kaynaklanan bazı doğrusal olmayan durumlar ve simetri bozuklukları mevcuttur. Kontrolcü tasarımı ve kontrolcü parametrelerinin en iyilenmesi için tüm hareket denklemleri türetilmiş, sistemin ayrıntılı doğrusal ve doğrusal olmayan matematiksel modelleri elde edilmiştir. Bu parametreler, doğrusal olmayan model kullanılarak MATLAB Response Optimization Tools yardımıyla elde edilmiştir. Kaldıraç mekanizmalı ve bilyalı vidalı elektromekanik kontrol tahrik sisteminin ilk prototipi üretilmiştir ve prototip üzerinde gerçek zamanlı testler yapılarak doğrusal olmayan benzetim modeli doğrulanmıştır

Identification of Viscous and Coulomb Friction in Motion Constrained Systems

In this study, a simple and inexpensive method is developed in order to identify viscous and Coulomb frictions in systems with motion limitations. This method is used on a prototype. A series of tests are performed using position profiles with different speeds created according to motion limits in the systems. Using the data obtained from these tests, viscous and Coulomb friction characteristics are identified for both negative and positive motion directions. The method developed can also be used to determine whether the Coulomb friction is position dependent or not and the change of Coulomb friction with the position

Collision Free Motion Planning for Double Turret System Operating in a Common Workspace

© 2021, ICROS, KIEE and Springer.Instead of using the tedious process of turret teaching, an off-line path planning algorithm has been developed for military turrets to improve their accuracy and efficiency. In the scope of this research, an algorithm is proposed to search a path in three different types of configuration spaces which are rectangular, circular and torus shaped by providing three converging options named as fast, medium and optimum depending on the application. With the help of the proposed algorithm, 4-dimensional (D) path planning problem was realized as 2-D + 2-D by using 6 sequences and their options. In order to find a heuristic path on these 2-D configuration maps, the A* algorithm is implemented, which is usually used to find a heuristic path on Cartesian Workspace. Firstly, 4-D configuration space of the double-turret system is obtained by using the method of intersection of point clouds where the bodies in the system are meshed and converted into points. With the help of random simulations, the sequences and the options of these sequences are provided in an appropriate order. A sample path planning was made to examine the performance of the algorithm and thus the converging options. The results obtained for 3 different converging options were simulated on the model of the double-turret system and it was observed that there was no collision between any bodies in these three options. Hence, a collision free motion planning can be carried out for double-turret system operating in a common workspace

DYNAMIC MODELING AND CONTROL OF AN ELECTROMECHANICAL CONTROL ACTUATION SYSTEM

Electromechanical actuators are widely used in miscellaneous applications in engineering such as aircrafts, missiles, etc. due to their momentary overdrive capability, long-term storability, and low quiescent power/low maintenance characteristics. This work focuses on electromechanical control actuation systems (CAS) that are composed of a brushless direct current motor, ball screw, and lever mechanism. In this type of CAS, nonlinearity and asymmetry occur due to the lever mechanism itself, saturation limits, Coulomb friction, backlash, and initial mounting position of lever mechanism. In this study, both nonlinear and linear mathematical models are obtained using governing equations of motion. By using the linear model, it is shown that employing a PI-controller for position and a P-controller for velocity will be sufficient to satisfy performance requirements in the inner-loop control of an electromechanical CAS. The unknown controller parameters and anti-windup coefficient are obtained by the Optimization Tools of MATLAB using nonlinear model. Results obtained from the nonlinear model and real-time unloaded and loaded tests on a prototype developed are compared to verify the nonlinear model