Advanced Integrated Power and Attitude Control System (IPACS) study

Integrated Power and Attitude Control System (IPACS) studies performed over a decade ago established the feasibility of simultaneously satisfying the demands of energy storage and attitude control through the use of rotating flywheels. It was demonstrated that, for a wide spectrum of applications, such a system possessed many advantages over contemporary energy storage and attitude control approaches. More recent technology advances in composite material rotors, magnetic suspension systems, and power control electronics have triggered new optimism regarding the applicability and merits of this concept. This study is undertaken to define an advanced IPACS and to evaluate its merits for a space station application. System and component designs are developed to establish the performance of this concept and system trade studies conducted to examine the viability of this approach relative to conventional candidate systems. It is clearly demonstrated that an advanced IPACS concept is not only feasible, but also offers substantial savings in mass and life-cycle cost for the space station mission

Electromagnetic system analysis and improvement of a novel 3-DOF deflection type permanent magnet motor

Ovaj rad predstavlja elektromagnetsku analizu novog motora s permanentnim magnetom na hibridni pogon s više stupnjeva slobode zasnovan na analitičkoj i 3D metodi konačnih elemenata. Prezentirani su i razvijeni proračunski model prostornog magnetskog polja, model analize zakretnog momenta, model uljnog sloja i elektromagnetsko-toplinske spojke. Na temelju simulacijskih rezultata proračuna, nekih važnih značajki karakteristika magnetskog polja i zakretnog momenta, izvedeni su uljni sloj i elektromagnetsko-toplinska spojka i detaljno proanalizirani njihovi učinci s nekim daljnjim mogućnostima poboljšanja oblikovanja. Rezultati pružaju primarni teorijski vodič za dizajn konfiguracije, optimizaciju i istraživanje reguliranja aktuatora deflekcijskog tipa s tri stupnja slobode.This paper presents the electromagnetic analysis of a novel fluid damping based hybrid drive multi-degrees-of-freedom permanent magnet motor based on analytical and 3D finite element methods. The spatial magnetic field calculation model, torque analysis model, oil film model and electromagnetic-thermal coupling are presented and developed. Based on the simulation calculation results, some important features on the magnetic field and torque characteristics, oil film and electromagnetic-thermal coupling are derived and their effects are discussed in detail with some further improvement design possibilities. The results provide the primary theoretical guide for the configuration design, optimization and control research of three degrees of freedom deflection type actuators

Vibration mode analysis of multi-degree-of-freedom permanent magnet synchronous motor

Multi-degree-of-freedom motors have attracted more and more attentions, and the liquid suspension multi-degree-of-freedom PM motor is regarded as one of the research hotspots of new kind of electrical machine. In order to further optimize the structure of liquid suspension permanent magnet synchronous multi-degree-of-freedom motor and improve the stability of the operation, the mode force analysis of the motor's component is carried out. The characteristics and basic structure of the motor are introduced, and the principle and rules of the motor resonance are expounded in detail. Based on the theory of mechanics, the mode of the motor spherical shell is studied and calculated. By finite element analysis, the modal changes of stator shell under static and energized conditions are calculated and the comparison is made. Then, the 2nd order modal deformation of the spherical shell is monitored by hammering and sensor with the measured data obtained and compared with the finite element simulation. The solid mechanical structure of the claw stator core is analyzed so that the stress distribution and deformation displacement distribution are obtained. The results of the simulation and analysis provide the reference for the optimal design of this kind of motors or actuators

Multi-objective optimization of a magnetically levitated planar motor with multi-layer windings

In this paper, a novel magnetically levitated coreless planar motor with three-layer orthogonal overlapping windings is shown to have higher power density and higher space utilization compared to other coreless planar motors. In order to achieve maximum forces with minimum cost and minimum space, a multi-objective optimization of the novel planar motor is carried out. In order to reduce the computational resources required for finite element analyses, a fast but accurate analytical tool is developed, based on expressions of the flux density of the permanent magnet array, which are derived from the scalar magnetic potential method. The validity and accuracy is verified by 3D FE results. Based on the force formulas and the multi-objective function derived from the analytical models, a particle swarm optimization (PSO) algorithm is applied to optimize the dimensions of the planar motor. The design and optimization of the planar motor is validated with experimental results, measured on a built prototype, thus proving the validity of the analytical tools

Mathematical model of two-degree-of-freedom direct drive induction motor considering coupling effect

The Two-degree-of-freedom direct drive induction motor, which is capable of linear, rotary and helical two, has a wide application in special industry such as industrial robot arms. It is inevitable that the linear motion and rotary motion generate coupling effect on each other on account of the high integration. The analysis of this effect has great significance in the research of two-degree-of-freedom motors, which is also crucial to realize precision control of them. The coupling factor considering the coupling effect is proposed and addressed by 3D finite element method. Then the corrected mathematical model is presented by importing the coupling factor. The results from it are verified by 3D finite element model and prototype test, which validates the corrected mathematical model

Simulation of Electromechanically Actuated Boom

Environmental consciousness has made electrification of mobile machines a popular trend in recent years. Electromechanical linear actuators (EMLAs) may be used to replace hydraulic cylinders in mobile machines. In this thesis a simulation model for a boom with single EMLA is developed. The EMLA consists of a permanent magnet synchronous motor (PMSM), gearbox and ball screw. The objective of this thesis is to develop a simulation model that includes the EMLA, the control system and the mechanical model of the boom. The simulations are carried out in Matlab Simulink environment. The simulation model is validated by comparing simulation results with measurement data of the actual system. Structure, operating principle, mathematical equations and common control structure of PMSM are introduced to develop a simulation model for the motor and motor controller. The motor used in this thesis uses Hall sensors as feedback device. The downsides and challenges of using such low-resolution sensors are also covered in this thesis. A spring-mass model is used to model the mechanics of the actuator. The equations to obtain parameters for the spring mass models are introduced. Friction of the actuator is also studied, and it is found out that there are no friction models that could predict the friction accurately using basic parameters of the ball-screw. There are many components corresponding to total friction and developing an experimental model is the best option. A simple assumption of constant efficiency of the actuator is used in this thesis. The simulation model of the motor and motor controller was validated independently of the rest of the system by utilizing a motor test bench. It was found out that the models are sufficiently accurate to be used for complete system modelling, including the EMLA and the boom. The complete model was then developed, and the results were compared with measurement data from the real system. The results showed similarities and the simulator managed to show controllability issues of the real system. The issues were caused by slow control loop frequency and delay in the control loop. To improve the systems performance a motor and a motor controller better suited for motion control applications should be used. It was found out that the simple friction model used is not accurate and a better model should be developed