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 : 25 - 10000N Dynamic Force : 6.5um ± 10% um @100V ACTIVE VIBRATION CONTROL Stiffness : 12 - 267 N/um HIGH SPEED SWITCHING Frequency range : 40-135 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