Methodology of the main drive selection for a human centrifuge

U ovom radu je iznet je problem izbora glavnog pogona za humanu centrifugu, počev od anvelope leta koju je potrebno simulirati. Osnovni cilj je da se naglasi složenost izbora pogona, jer je u pitanju motor velike snage. Metodologija izbora glavnog pogona centrifuge za obuku pilota, koja predstavlja manipulator sa tri stepena slobode kretanja, zasnovana je na glavnom zahtevu, da se postigne ekstremni gradijent i koeficijent opterećenja u jedinici vremena. Metodologija se sastoji u određivanju potrebnog obrtnog momenta i snage glavnog pogona centrifuge. Da bi se postigao osnovni zahtev, motor mora raditi sa preopterećenjem u datom vremenskom intervalu u početnom trenutku. Za proračune i dijagrame, program MATLAB je korišćen. U ovom radu dat je primer motora švajcarskog proizvođača ABB. Njegove karakteristike su objašnjene detaljno, u odnosu na potrebni obrtni moment i snagu glavnog pogona. Sve numeričke vrednosti u ovom radu, su deo preliminarnog proračuna.In this paper, the issue of the main drive selection for a Human Centrifuge is explained, starting from the flight envelope that needs to be simulated. The main objective is to emphasize the complexity of choosing a drive, since it is a high power drive. The methodology for the main drive selection of a Centrifuge for pilot training, which is a manipulator with three degrees of freedom of motion, is built upon the main demand to achieve an extreme gradient and load coefficient per unit of time. The methodology consists of determining the necessary torque and power of the main drive of the Centrifuge. To achieve the main requirement, the engine has to work with an overload in a given time interval at the beginning. For calculations and diagrams, the MATLAB program was used. In this paper, an example of a motor of the Swiss manufacturer ABB is given. Its features are explained in detail, according to the needed torque and power of the main drive. All numerical values in this paper, are a part of a preliminary calculation

Methodology of the main drive selection for a human centrifuge

U ovom radu je iznet je problem izbora glavnog pogona za humanu centrifugu, počev od anvelope leta koju je potrebno simulirati. Osnovni cilj je da se naglasi složenost izbora pogona, jer je u pitanju motor velike snage. Metodologija izbora glavnog pogona centrifuge za obuku pilota, koja predstavlja manipulator sa tri stepena slobode kretanja, zasnovana je na glavnom zahtevu, da se postigne ekstremni gradijent i koeficijent opterećenja u jedinici vremena. Metodologija se sastoji u određivanju potrebnog obrtnog momenta i snage glavnog pogona centrifuge. Da bi se postigao osnovni zahtev, motor mora raditi sa preopterećenjem u datom vremenskom intervalu u početnom trenutku. Za proračune i dijagrame, program MATLAB je korišćen. U ovom radu dat je primer motora švajcarskog proizvođača ABB. Njegove karakteristike su objašnjene detaljno, u odnosu na potrebni obrtni moment i snagu glavnog pogona. Sve numeričke vrednosti u ovom radu, su deo preliminarnog proračuna.In this paper, the issue of the main drive selection for a Human Centrifuge is explained, starting from the flight envelope that needs to be simulated. The main objective is to emphasize the complexity of choosing a drive, since it is a high power drive. The methodology for the main drive selection of a Centrifuge for pilot training, which is a manipulator with three degrees of freedom of motion, is built upon the main demand to achieve an extreme gradient and load coefficient per unit of time. The methodology consists of determining the necessary torque and power of the main drive of the Centrifuge. To achieve the main requirement, the engine has to work with an overload in a given time interval at the beginning. For calculations and diagrams, the MATLAB program was used. In this paper, an example of a motor of the Swiss manufacturer ABB is given. Its features are explained in detail, according to the needed torque and power of the main drive. All numerical values in this paper, are a part of a preliminary calculation

Control System Design for a Centrifuge Motion Simulator Based on a Dynamic Model

This paper presents a dynamic model-based design of a control system and an approach toward a drive selection of a centrifuge motion simulator (CMS). The objective of the presented method is to achieve the desired performance while taking into account the complexity of the control system and the overall device cost An estimation of a dynamic interaction of the interconnected CMS links motions is performed using the suitable inverse dynamics simulation. An algorithm based on the approximate inverse dynamics model is used within the drive selection method. The model of the actuator's mechanical subsystem includes the effective inertia (inertia reflected on the rotor shaft) calculated from the inverse dynamics model. A centralized control strategy based on a computed torque method is considered and compared to traditional decentralized motion controllers To obtain an accurate comparison of the suggested control methods through a realistic simulation, structural natural frequencies of the manipulator links are considered, and the actuator capabilities are taken into account The control system design and simulation methods and the drive selection strategies, presented here for the CMS, are applicable within the general robot manipulator's domain

Computed torque control for a spatial disorientation trainer

A development of a robot control system is a highly complex task due to nonlinear dynamic coupling between the robot links. Advanced robot control strategies often entail difficulties in implementation, and prospective benefits of their application need to be analyzed using simulation techniques. Computed torque control (CTC) is a feed-forward control method used for tracking of robot's time-varying trajectories in the presence of varying loads. For the implementation of CTC, the inverse dynamics model of the robot manipulator has to be developed. In this paper, the addition of CTC compensator to the feedback controller is considered for a Spatial disorientation trainer (SDT). This pilot training system is modeled as a 4DoF robot manipulator with revolute joints. For the designed mechanical structure, chosen actuators and considered motion of the SDT, CTC-based control system performance is compared with the traditional speed PI controller using the realistic simulation model. The simulation results, which showed significant improvement in the trajectory tracking for the designed SDT, can be used for the control system design purpose as well as within mechanical design verification

COMPUTED TORQUE CONTROL FOR A SPATIAL DISORIENTATION TRAINER

A development of a robot control system is a highly complex task due to nonlinear dynamic coupling between the robot links. Advanced robot control strategies often entail difficulties in implementation, and prospective benefits of their application need to be analyzed using simulation techniques. Computed torque control (CTC) is a feedforward control method used for tracking of robot’s time-varying trajectories in the presence of varying loads. For the implementation of CTC, the inverse dynamics model of the robot manipulator has to be developed. In this paper, the addition of CTC compensator to the feedback controller is considered for a Spatial disorientation trainer (SDT). This pilot training system is modeled as a 4DoF robot manipulator with revolute joints. For the designed mechanical structure, chosen actuators and considered motion of the SDT, CTC-based control system performance is compared with the traditional speed PI controller using the realistic simulation model. The simulation results, which showed significant improvement in the trajectory tracking for the designed SDT, can be used for the control system design purpose as well as within mechanical design verification

Robust Stability of Singularly Impulsive Dynamical Systems

In this paper, we present results of the robust stability analysis for the class of nonlinear uncertain singularly impulsive dynamical systems. We present sufficient conditions for the robust stability of a class of nonlinear uncertain singularly impulsive dynamical systems. The problem of evaluating performance bounds for a nonlinear-nonquadratic hybrid cost functional depending upon a class of nonlinear uncertain singularly impulsive dynamical systems is considered. It turns out that the cost bound can be evaluated in closed form as long as the hybrid cost functional is related in a specific way to an underlying Lyapunov function that guarantees robust stability over a prescribed uncertainty set. Then, results for the case of uncertain singularly impulsive dynamical systems are presented. The results obtained for the nonlinear case are further specialized to linear singularly impulsive dynamical systems

Advanced quaternion forward kinematics algorithm including overview of different methods for robot kinematics

Formulisanje odgovarajućih i efikasnih algoritama kinematike robota je od suštinskog značaja za analizu i razvoj serijskih manipulatora. Kinematičko modelovanje manipulatora se najčešće vrši u Dekartovom prostoru. Međutim, usled nedostataka najzastupljenijih matematičkih operatora za definisanje orijentacije kao što su Ojlerovi uglovi i rotacione matrice, nameće se potreba za jednoznačnim, kompaktnim, računski efikasnim metodom za određivanje orijentacije. Kao rešenje ovog problema predlažu se jedinični kvaternioni kao i razvoj kinematičkih modela u prostoru dualnih kvaterniona. U ovom radu je dat pregled geometrijskih opisa i transformacija koje se mogu primeniti u okviru navedenih prostora kako bi se rešili problemi kinematike robota. Poseban akcenat je na različitim matematičkim formalizmima koji se koriste za definisanje orijentacije krutog tela, kao što su rotacione matrice, Ojlerovi uglovi, osa i ugao rotacije, jedinični kvaternioni, kao i na njihovoj uzajamnoj vezi. Prednosti kinematičkog modeliranja u prostoru kvaterniona su istaknute. Osobine jediničnih i dualnih kvaterniona se analiziraju sa stanovišta robotike. Takođe, dat je novi algoritam direktne kinematike robota u prostoru dualnih kvaterniona. Ovaj algoritam je primenjen na humanoj centrifugi koja je modelirana kao troosni manipulator.Formulation of proper and efficient algorithms for robot kinematics is essential for the analysis and design of serial manipulators. Kinematic modeling of manipulators is most often performed in Cartesian space. However, due to disadvantages of most widely used mathematical constructs for description of orientation such as Euler angles and rotational matrices, a need for unambiguous, compact, singularity free, computationally efficient method for representing rotational information is imposed. As a solution, unit quaternions are proposed and kinematic modeling in dual quaternion space arose. In this paper, an overview of spatial descriptions and transformations that can be applied together within these spaces in order to solve kinematic problems is presented. Special emphasis is on a different mathematical formalisms used to represent attitude of a rigid body such as rotation matrix, Euler angles, axis-angle representation, unit quaternions, and their mutual relation. Benefits of kinematic modeling in quaternion space are presented. New direct kinematics algorithm in dual quaternion space pertaining to a particular manipulator is given. These constructs and algorithms are demonstrated on the human centrifuge as 3 DoF robot manipulator

OPEN ARCHITECTURE PLATFORMS FOR THE CONTROL OF ROBOTIC SYSTEMS AND A PROPOSED REFERENCE ARCHITECTURE MODEL

This paper presents advantages of using open architecture for the real-time control of robot manipulators, parallel kinematics machine tools and other multi-axis machining systems. In order to increase their competitiveness, companies need to follow the global economy requirements. The constant incorporation of new technologies into existing controllers and reduction in the development time and costs are the main objectives. An open architecture control (OAC) concept appears as a solution to deal with these requirements. This article explains the rationale for the development of OAC systems, presents the major international activities which propose various approaches to OACs and a series of controllers that have been developed using this design philosophy at the Lola Institute

Forward and inverse kinematics for vertical 5-axis turning center with angular head of non-intersectional axes, with compensation for table moving caused by base thermal dilatation

The paper presents the solution for forward and inverse kinematics of the vertical 5-axis turning centers with 2 linear and 3 rotational axes (Cy, X, Z, Bt and Ct) which for the 5-axis milling achieves the motion accomplished by 3 linear and 2 rotational axes (X, Y, Z, Bt and Cy). It has been done in such a way to provide for machine motion programming as if machining were performed on a 5-axis gantry milling machine. This has essentially facilitated machine programming, because tool positions and orientations required for programming are determined disregarding the workpiece swiveling during machining and current positions and orientations taken by the tool during machining relative to the workpiece. Turning center has a 2-rotary-axis head with axes Ct and Bt which do not intersect. This type of angular head has increased the possibilities of machining and allowed for performing certain types of machining without machine’s taking the singular positions, but it has made the machine control algorithm more complex. A high number of rotating of the table, required for turning, causes heating of the table bearing support and base thermal dilatation. If milling or drilling is done immediately after turning, the table and X axis motion control should be corrected to eliminate the error in machining appeared due to dilatation, as has been done in this paper

Procedure for definition of end-effector orientation in planar surfaces robot applications

Razvoj moćnih metoda za programiranje robota koje su ujedno i korisnički prilagođene je tema značajnih istraživanja u robotskoj zajednici. Radi olakšavanja programiranja robota, pojavljuje se ideja o razvoju standardnih procedura za programiranje najčešće prisutnih robotskih zadataka, a koje se mogu univerzalno lako upotrebiti kao gotov deo (ready-made) korisničkog programa. Važna klasa aplikacija industrijskih robota podrazumeva kretanje hvatača (end-effector) u paralelnim ravnima. U ovom radu je prikazan razvoj procedure jezika za programiranje robota koja služi za određivanje normale ravni objekta u odnosu na koordinatni sistem od značaja, kao i osnova procedure za automatizovani postupak programiranja orijentacije hvatača u odnosu na ravan objekta. Ova procedura se može koristiti kao integralni deo task oriented metoda programiranja robota, a takođe kao i procedura eksplicitnog robotskog programskog jezika, i ilustrovana je kroz praktični primer na robotu Lola 15.Design of user-friendly and at the same time powerful robot programming methods is the subject of significant efforts undertaken by the international robotics community. For the purpose of facilitating robot programming, with regard to the most common present-day applications in industry, it would be useful to develop programming procedures for frequently used manipulator tasks which could be easily implemented and used as ready-made application software. Important class of industrial robot applications involves end-effector trajectories in planar surfaces. Development of robot programming language procedure intended for determination of object plane normal with respect to frame of interest, as well as programming of end-effector orientation is presented in this paper. This procedure can be used as integral part of task oriented robot programing applications as well as a procedure for explicit programming languages, and it is illustrated in practical example with the robot Lola 15