Dizajn servo mehanizma za upravljanje krilima rakete u ravni propinjanja i skretanja

This paper explores the design and implementation of a servo mechanism utilizing DC electromotors for control of missile fin position. This research is focused on the analysis and optimization of DC electromotors to enhance the performance of servo systems in terms of speed, torque, accuracy and efficiency. Combination of theoretical approaches and experimental test were performed to validate the proposed mechanical construction of a servo mechanism.

Background: Electro-hydraulic position servo system is widely used, in order to cope with complex working conditions, the system is required to have high dynamic response and accurate position control ability, while the characteristics of the system and its control strategy need to be studied in depth. Objective: To review the characteristics of electro-hydraulic position servo systems and typical control strategies under complex working conditions, and summarize their advantages and disadvantages to provide a basis for the design and optimization of electro-hydraulic position servo systems. Methods: Literature and patents related to electrohydraulic position servo system characteristics and control strategies are collected, synthesized and summarized. Results: The characteristics of electro-hydraulic position servo system under complex working conditions are summarized, especially the performance of the system and the application effect of the control strategy under the working conditions such as load disturbance and gap nonlinearity. In addition, the application of sliding mode control, adaptive control and neural network control in electrohydraulic servo systems is summarized. Conclusion: In different complex working conditions, the selection of appropriate control strategies can improve the performance and stability of electro-hydraulic position servo systems. The study of the characteristics of electro-hydraulic position servo systems and typical control strategies is of great significance to the development of electro-hydraulic position servo systems.

Monitoring of the mechanical load and thermal history during friction stir channelling under constant position and constant force control modes

This thesis is a study on the implementation of an elevator’s position-controlled electric drive. The information contained within this paper serves as a framework to expand the usefulness of electric drives through the addition of digital control systems and switching power supplies. The tangible example of an elevator driven by a permanent-magnet DC motor is used for this paper so that students may relate to the work and apply it to their future projects. The tasks to be accomplished in order to achieve an electric elevator drive with position control are: determining the parameters of the permanent-magnet DC motor, designing a control system to direct the motor as desired, and verifying the performance of the system through use of computer simulations and experimental testing. The tests to derive the motor parameters as well as the theory behind the test are covered in depth before the design procedures for creating a cascaded control system are started. Computer simulations are conducted using the parameters and controllers which will be implemented in real-time before experimental testing in the lab begins. Conclusions are drawn about the performance of the position-controlled electric elevator drive based upon the simulation and experimental results. The implementation of an elevator driven by a permanent-magnet DC motor with position control is successful and provides an illustrative example to those who wish to apply electric drives to various mechanical systems

In the chapter issues related to the application of the Model Predictive Control (MPC) to position control of a drive system with an induction motor (IM) coupled to a load machine through a long shaft are presented. After a short introduction the mathematical model of IM is demonstrated. Then, the standard MPC algorithm is described in detail. Next, the proposed MPC-based position control structure is introduced. Contrary to the classical cascade structure with independent position and speed control loops, one MPC controller which regulates those two variables is designed. An additional fuzzy block allowing adaptation of MPC parameters is used. The tested MPC controller cooperates with DTC-SVM (direct torque control—space vector modulation) strategy of electromagnetic torque regulation including operation in the field weakening regions. The theoretical considerations are supported by a variety of simulation and experimental tests.

An adaptive sliding mode controller (ASMC) based on characteristic model is designed to overcome the detri- mental effect of large inertia ratio and large-range varying inertia in high accuracy servo systems. The servo system dis- crete characteristic model is established and adopted for the controller designed instead of using the traditional mechanism model. The recursive least square (RLS) algorithm is used to identify time-varying parameters in characteristic model. The position controller is constituted by an adaptive equivalent controller based on identification parameters and an im- proved sliding mode controller, and the stability of the closed-loop system is analyzed. The experimental results show that the proposed controller can adapt to large-range varying inertia, and improve the dynamic performance and steady-state precision of servo systems.

This paper presents an experimental exploration of position control techniques applied to a Rotary Motion Servo Plant (SRV02), employing output feedback controllers. The transfer function model of the SRV02 is derived through first principles. Output feedback controllers, specifically Position Velocity (PV) and Multirate Output Feedback (MOF), are formulated and designed. The study evaluates the efficacy of these controllers in real-world scenarios for positioning control of the SRV02. A comparative analysis between PV and MOF controllers was conducted, assessing their static and dynamic characteristics. The results, obtained from both simulation and experimental setups, illustrate the superiority of MOF over PV controller in achieving precise position control of the SRV02. The findings of this study not only validate the effectiveness of MOF in position control applications but also provide insights into the practical implementation of output feedback controllers for enhancing the performance of rotary motion servo systems like SRV02.

Close proximity operations demand an accurate control in a micro-gravity environment, hence they must be reproduced and simulated systematically. Consequently, laboratory tests are a crucial aspect to validate the performances of space systems. This paper presents the development of a floating pneumatic module, whose dimensions and mass are representative of a 12U CubeSat. The vehicle has been designed to perform planar low friction motion over a levelled table for docking experiments. The paper focuses on the pneumatic and mechanical designs and on the laboratory tests of the module. The pneumatic design regards the air-compressed pneumatic system. The major specifics have been determined by the requirement of performing a docking procedure by starting from a distance of 500 mm. The mechanical design has been guided by two main requirements. The first is the possibility to accommodate different docking systems (e.g.: docking port). The second is the possibility to control the position of the centre of mass of the module. Several tests have been performed to verify the capabilities of the vehicle, such as: (1) pneumatic tests to evaluate the thrust of the propulsion system through the execution of linear motions and (2) mechanical measurements with dedicated setups to improve the estimation of the position of the centre of mass from the CAD model of the system.

This paper describes design, construction and control of a 3-RRR planar parallel mechanism. The focus is on experimental control methods using inverse kinematic problem in order to gain more accuracy and smooth movement during the control process. Since there is no direct feedback sensor on the end-effector, all the foregoing control approaches could be regarded as open-loop control. In order to control the mechanism, two main control methods are used namely, position control and speed control. A Joy-stick is added to the system, in order to provide the ability for the user to control the mechanism directly. In addition, a Graphical User Interface is designed to help the user by three main control states. The first state is considered as off-line control, in which, the mechanism will follow a specific path defined in the program. In the second state, off-line control via Joy-stick, the mechanism will follow a path specified by the user via Joy-stick. As the third state, which is considered as the on-line control via Joy-stick, the mechanism will interactively follow a path specified by the user via the Joy-stick. All the programs are written in Qt creator in order to speed up data transmission from computer to the mechanism's actuators and vice versa. Results reveal that the mean error value of the actual and the desired angles of actuators is 0.68 degree, which illustrates that the mechanism has sufficient accuracy when the joints backlash are ignored.

A position control solution for hybrid stepper motor is presented with a low-cost Magnetic Rotary Position Sensor. A harmonic compensation method based on linear regression algorithm is shown to improve the performance of the low-cost position sensor. A sensor fusion algorithm based on Extended Kalman Filter is evaluated to further eliminate the signal error. In the sensor fusion process, a position signal calculated from back-emf measurements is fused with position signal from the low-cost position sensor and the result is discussed on practical purpose. For the position control, the control strategy is based on vector control. PID controllers are involved in both current and position control loops. Additional speed and acceleration terms are taken into account to form the position controller. An experimental test are run with a motor trajectory from an industrial implementation in the end and positive results prove the feasibility of this low-cost solution.

This paper is a study on the real-time implementation of a position-control based electric elevator drive. The information contained within this paper serves as a framework to expand the usefulness of electric drives through the addition of digital control systems and switching power supplies. The tangible example of an elevator driven by a permanent-magnet DC motor with position control is used to relate to the work and apply it to various mechanical systems. The tasks to be accomplished to achieve an electric elevator drive with position control are as follows: determining the parameters of the motor, designing a control system to direct the motor as desired, and verifying the performance of the system through the use of computer simulations and real-time Hardware-In-The-Loop (HIL) experimental testing.

The J-integral is an important concept in the elastic-plastic fracture mechanics, and serves as a critical material parameter to quantify the toughness or resistance of ductile materials against fracture. The relation between the J-integral and crack extension has been widely used as the resistance curve of ductile materials in fracture mechanics design and in structural integrity assessment. Experimental testing and evaluation have played a central role in providing reliable fracture toughness properties to fracture mechanics analysis. Since the J-integral concept was proposed, extensive efforts of investigations have been made to develop its experimental estimation method, testing technique and standardization, as evident in the ASTM E1820 — a commonly used fracture toughness testing standard. In recent years, significant progresses of the J-integral fracture testing and experimental estimation have been achieved, and a part of them was accepted and updated in ASTM E1820. To better understand and use this fracture testing standard, the present paper gives a brief review of historical efforts and recent advances in the development of the J-integral experimental estimation and standard testing.

Tissue containment systems (TCS) are medical devices that may be used during morcellation procedures during minimally invasive laparoscopic surgery. TCS are not new devices but their use as a potential mitigation for the spread of occult malignancy during laparoscopic power morcellation of fibroids and/or the uterus has been the subject of interest following reports of upstaging of previously undetected sarcoma in women who underwent a laparoscopic hysterectomy. Development of standardized test methods and acceptance criteria to evaluate the safety and performance of these devices will speed development, allowing for more devices to benefit patients. As a part of this study, a series of preclinical experimental bench test methods were developed to evaluate the mechanical and leakage performance of TCS that may be used in power morcellation procedures. Experimental tests were developed to evaluate mechanical integrity, e.g., tensile, burst, puncture, and penetration strengths for the TCS, and leakage integrity, e.g., dye and microbiological leakage (both acting as surrogates for blood and cancer cells) through the TCS. In addition, to evaluate both mechanical integrity and leakage integrity as a combined methodology, partial puncture and dye leakage was conducted on the TCS to evaluate the potential for leakage due to partial damage caused by surgical tools. Samples from 7 different TCSs were subjected to preclinical bench testing to evaluate leakage and mechanical performance. The performance of the TCSs varied significantly between different brands. The leakage pressure of the TCS varied between 26 and > 1293 mmHg for the 7 TCS brands. Similarly, the tensile force to failure, burst pressure, and puncture force varied between 14 and 80 MPa, 2 and 78 psi, and 2.5 N and 47 N, respectively. The mechanical failure and leakage performance of the TCS were different for homogeneous and composite TCSs. The test methods reported in this study may facilitate the development and regulatory review of these devices, may help compare TCS performance between devices, and increase provider and patient accessibility to improved tissue containment technologies.

Different from typical servo systems that take position control as the first priority, rail transit door needs to reach the specified position with the established speed curve, so as to meet the safety requirements. Hence, both speed control and position control are simultaneously required, which cannot be achieved by the conventional cascaded position-speed-current loop structure. In this paper, an integrated position and speed control method for rail transit door based on speed-current loop structure is proposed. The movement of the door is divided into four stages, in which the speed mode or position mode are applied according to the instantaneous position of the door. In the last stage of position servo, in order to improve the accuracy of position control at low speed and meet the safety requirements, a method based on chopper regulator is proposed to realize servo accuracy and accident protection by adjusting the chopper current limit. Simulation and experimental results show that the proposed method is effective and easy to implement in engineering practice.

In this paper, the parameters choice of a fuzzy logic regulator used to control the position of a six-phase induction motor for a car steering is performed. Indeed, with the presence of an electronic stability controller (ESC), the braking on the four wheels is controlled and the correction of the direction to adjust the path of the vehicle is also made. Obviously, the position control should never present on overshoot and should be insensitive to the mechanical loads, and it has to operate in faulted mode as well (when electrical machine phases are missing). In this paper, a fuzzy logic controller applied to a six phase induction machine has been developed to realize an effective position control. Some experimental tests in healthy and faulty (1, 2 and 3 missing phases) modes were performed to check the robustness and the accuracy of this controller. In addition, a study concerning the position errors of each operating case will be presented.