Efforts By : Ankit Puri Project Supervisor : Fangpo He

Contents  Quick Recap.  Mechanical Structure.  Cons of using Peizo.  New Model Mechanical Structure.  Magnetic Actuator and Working.  Simulation Results.  Conclusion.

RECAP

RECAP (Continued…)

Mechanical Structure  The aim is to control vibration of gun barrel structure.  Earlier stage of gun barrel.

Specifications of Earlier Stage  Rigid Structure that is displacement in micro meter range. (ie 10 um)  Requires rapid and precise movement of control.  Should have a preloading stage at start.  Light and Handy structure.  Sensor to sense the movement.

Selected Actuator  Peizo-Actuator WHY ??? PRECISE MECHANICS Max Blocking Force : N Dynamic Force : 6.5um ± 10% ACTIVE VIBRATION CONTROL Stiffness : N/um HIGH SPEED SWITCHING Frequency range : KHz ± 20% Sub millisecond response. DURABLE & LIGHT WEIGHT Can be made according to need any size & dimension.

Cons of choosing Peizo  Too Expensive nearly 5000 US$  Technical Difficulties in Hardware Implementation.

New Mechanical Structure  Less Rigid that is more movement / vibration of barrel.  Able to control from actuators available in market.  Gives more time to settle and control practically.  Practically implementation Possible.

Electro-Magnetic Actuators  Before Further Moving it is important to know about  What Are Magnets ? How they Work ? A magnet is any object that has a magnetic field. It Attracts ferrous objects like pieces of iron, steel, nickel and cobalt. Also like Magnetic poles repel each other whereas unlike poles attract each other.  What is Magnetic field ? How to create Magnetic field ? The space surrounding a magnet, in which magnetic force is exerted, is called magnetic field. If a bar magnet is placed in such a field, it will experience magnetic forces. However, the field will continue to exist even if the magnet is removed.  Principle Of Working ? Similarly an experiment done by Oersted in 1820 found “a current flowing in a wire produces a magnetic field around it.” The magnetic effect of current is called electromagnetism which means that electricity produces magnetism.

Types of Magnetic Actuators  Magnetic actuators use magnetic effects to generate forces which impact on the motion of a part in the actuator. They give a stroke range of 1 to 20 mm. Moving Actuator Moving Iron Actuator Moving Core Actuator Moving Coil Actuator Magnetostrictive Actuator Magneto Rheological Fluid Actuator

Using a Permanent Electromagnet  We tried our experiment on KEP-5c model of electromagnetic actuator to test the magnetic field interaction of the barrel. The results are below. Without ActuatorWith Actuator 6V With Actuator 24 V 10.2 sec9.1 sec8.0 sec 9.7 sec9.0 sec8.1 sec 9.9 sec8.8 sec7.9 sec

Disadvantages  From the experiment it was proven that the barrel vibration cuts the magnetic lines of forces produced by electromagnet but the responses are not linear in nature.  Also the relation between the voltage and gap clearance is not fixed.

Hardware Simulation  The simulation of the hardware is done in the Software named “Proteus”. The basic hardware parts connection is shown below.

Conclusion  The vibrations of any object to be control differs from its shape and size. The sensors and actuators have its own error margin and thus cannot give a perfect output.  The non-linear variation seen in the trend increases the level of difficulty of active control. Thus to resolve this, actuators of different types were tested.  As for future aspects the smart structure vibration can be controlled easily by use of custom made actuators which are precise and gives rapid movement of control. Any questions