The present work is about the design of a linear magnet for an artificial heart in the “Konstruktionsseminar Summer term 2014” at the University of Applied Science HS Pforzheim. This work is one part of three different topics about the heart in the course “electric machines”. It covers the simulation and optimization of the engine from an artificial heart using a linear magnet or further named solenoid. In the winter term 2013, the last semester, a group of students already designed a virtual prototype of the heart and the magnet. But they could not meet the weight requirements therefore the goal and the focus in the “Konstruktionsseminar Summer term 2014” was to lower the total weight. However, no analyses had been made of the movement of the anchor and pushing the blood into the chamber. To lower the weight and to raise the power of the solenoid by an exchange of the material, the whole system will be more dynamic as before. To get an optimum of a low weight plus having a dynamic system, which can be controlled by changing the voltage and therefore the currency, the system is getting into an idly condition.
Table of Contents
1 Introduction
2 Description of the task
3 Initial situation
4 State of the Art
4.1 Magnetic force
4.2 Duty cycle
4.3 Inner resistance of the coil
4.4 Derivation of MSDS – Mass-Spring-Damper-System
4.4.1 The spring stiffness
4.4.2 The damper stiffness
4.4.3 The anchors mass
4.5 Airgap
5 From FEMM into a Simulink model
5.1 FEMM
5.2 Creating the Matlab Simulink model
5.2.1 Electric part of the Simulink model
5.2.2 Mechanical part of the Simulink model
6 Use of the system
7 Conclusion
Project Goals and Research Focus
This project aims to simulate and optimize the solenoid engine of an artificial heart to reduce its weight while increasing performance. The primary research focus is to analyze the anchor movement within a mass-spring-damper system (MSDS) using MATLAB Simulink and FEMM, aiming to control the movement through precise voltage and current regulation.
- Weight reduction and structural optimization of the solenoid.
- Modeling and analysis of anchor movement dynamics.
- Finite Element Method (FEM) simulation for magnetic properties.
- System integration into a mass-spring-damper control model.
- Validation of solenoid performance under specified physiological requirements.
Excerpt from the Book
4.4 Derivation of MSDS – Mass-Spring-Damper-System
A MSDS is a system in which the forces of the spring, damper and the mass of the moving part are shown. In general, it is a sum of all the components derived of the chapters 4.4.1, 4.4.2 and 4.4.3. Depending of there is an external force pushing on the system the equation is zero or the external force. In this case the MSDS is a mass oscillator with a single degree of freedom.
F_ext = m * a + d * v + c * s (equation 9)
Summary of Chapters
1 Introduction: Provides an overview of the artificial heart project, focusing on the design requirements and the necessity of weight reduction and dynamic control.
2 Description of the task: Details the solenoid-based actuator concept within an artificial heart, defining the high-pressure and low-pressure chambers and the mass-spring-damper system.
3 Initial situation: Presents the geometric design derived from previous work and explains the material modifications made to improve flux density and efficiency.
4 State of the Art: Explains the manual calculations for magnetic force, duty cycle, resistance, and the structural derivation of the mass-spring-damper system.
5 From FEMM into a Simulink model: Describes the integration of magnetic simulation data from FEMM into the MATLAB Simulink model to achieve a dynamic control loop.
6 Use of the system: Analyzes the behavior of the Simulink model under specific voltage inputs and evaluates the resulting solenoid performance.
7 Conclusion: Reviews the effectiveness of the control approach and suggests future improvements, such as adopting a proportional solenoid to better regulate movement.
Keywords
Artificial heart, Solenoid, MATLAB Simulink, FEMM, Mass-spring-damper system, MSDS, Anchor movement, Magnetic force, Duty cycle, Coil resistance, Control engineering, Fluid dynamics, Optimization.
Frequently Asked Questions
What is the primary objective of this project?
The project focuses on optimizing a solenoid engine for an artificial heart to lower its total weight and improve its force, ensuring dynamic performance via control engineering.
Which scientific tools are used to conduct the simulation?
The study utilizes MATLAB Simulink for system dynamics modeling and control, combined with FEMM to solve stationary magnetic field problems.
Why is the Mass-Spring-Damper system essential here?
The MSDS represents the physical behavior of the solenoid anchor, allowing the team to calculate motion, velocity, and acceleration under the influence of electromagnetic and spring forces.
What is the role of the duty cycle in this system?
The duty cycle is crucial for regulating the current through the coil, which in turn determines the magnetic force generated to move the solenoid anchor.
How is the magnetic force calculated?
Magnetic force is derived by considering the pressure required for blood circulation, the area of the membrane, and the requirements of an adult human heart rate.
What are the main constraints identified?
Key constraints include the weight of the solenoid, the temperature limitations of human body implementation, and the short time window available for anchor movement.
Why is current control difficult in this specific model?
The control is difficult because the system behaves as an idle state, making it hard to manage the movement effectively using only manual voltage regulation.
What does the conclusion suggest for future work?
The author recommends transitioning from a direct current solenoid to a proportional solenoid to allow for precise control of every movement step and implementing an active damping system.
- Quote paper
- Robert J. G. Wenndorff (Author), 2014, Simulation and Optimization of the Currency in a Matlab Model. Visualization of the Currency and the Voltage in Dependency of the Anchors Force, Munich, GRIN Verlag, https://www.grin.com/document/386648
