ELECTROMAGNETIC HAMMER STRIK-ER’S COORDINATE SENSOR

Abstract

Electromagnetic hammers are widely used in industry, construction, and mining. Research into hammer impact energy, frequency, productivity, and energy efficiency requires the development of systems for determining the striker's position and velocity. Hammer design and operating conditions often preclude the use of optical, resistive, and contact position sensors. This article examines the design of position detection system of the electromagnetic hammer striker with two power coils, which allows for calculating the striker's velocity and kinetic energy. The system is based on an internal combustion engine crankshaft position sensor. It was established that, for the position detection system to function correctly, grooves must be cut into the striker's surface. Tests of the developed system were conducted on a physical model of the hammer. The article determines the optimal groove width and depth, which are 1.5-2 mm each. The sensor end should be located 1-2 mm from the striker's surface. It was determined that the distance between the grooves should be at least 20 mm to accurately determine the coordinate and simplify the mathematical processing of the sensor signal. During testing, the striker's motion with zero initial velocity under the influence of gravity was studied. Using the oscillogram of the signal collected from the sensor, graphs were constructed showing the striker's velocity and displacement as a function of time. The shape of the graphs corresponds to uniformly accelerated motion. Furthermore, analysis of the graphs allowed us to determine the striker's acceleration, which differs from the gravity acceleration due to the influence of compression and vacuum resistance and friction. This confirms the correct operation of the developed system.