Development of an Experimental Method to Estimate the Operating Force of a Hand-Held Power Tool Utilizing Measured Transfer Functions

Abstract

Hand-arm vibration syndrome (HAVS) collectively refers to diseases caused by prolonged exposure to intensive hand-transmitted vibration, which has been affecting millions of workers who use hand-held power tools. The force interacting between a hand-held power tool and the work-piece is valuable basic information in studying hand-arm vibration problems, however cannot be measured directly. An experimental method is developed to estimate this tool force by utilizing the input point impedance of the hand and measured transfer functions of the tool. The developed method is applied to calculate the tool force of a hand-held grinder and a circular saw to demonstrate and validate the method. Possible applications of the method to study hand-arm vibration or tool design are explained.

Prediction of Tool Forces in Manual Grinding Using Consumer-Grade Sensors and Machine Learning

“…The problem is that the tool forces of hand-held grinding machines cannot be measured directly in the grinding contact [4]. The determination of tool forces, for example by modeling or sensor integration, is a challenge for hand-held power tools, especially when the motion is not clearly defined [5].…”

“…A transfer to field tests with arbitrary workpieces is not possible. An approach is to measure the acceleration at the handle of a hand-held grinding machine or workpiece to be machined and to calculate the tool forces using an experimentally determined transfer function [4]. With this approach, only high-pass filtered tool forces and no stationary ones can be determined.…”