Development of posture measuring apparatus using goniometer and inclinometer 1. Description of the Apparatus and Its Usefulness

Abstract

A new posture measuring apparatus was developed for time and motion study in the field of industrial health. This apparatus can record and classify working postures by measuring the angles of joints and trunk inclination. The angles of joints are measured by newly developed goniometers which use the bending loss of rubber optical fibers. The trunk inclination is measured by an inclinometer which uses photointerrupters. The measured angle data stored in the memory of this apparatus are transferred to the host computer and analyzed. Postures are classified automatically and subjectively according to discriminant functions which are calculated from the preliminarily measured data by discriminant analysis. Test measurement was carried out to classify four postures; standing, forward bending, half sitting and sitting. The goniometers were set on the right hip joint, knee joint, and ankle joint and the inclinometer was set on the right side of the trunk. The postures were changed in the order of standing, forward bending, half sitting, and sitting every 30s. The angles were measured every second and a total of 120 sets of angles were measured. All data including data during posture changing were classified correctly by discriminant functions. The measurement during baggage lifting up and putting down was also carried out. Ten baggages (each 7 kg in weight) were lifted up from the floor onto a desk (75 cm in height), put down back to the floor, and again lifted on the desk. In 2 min, baggages were lifted up for a total of 20 times and put down for a total of 10 times. The difference between forward bending posture and half sitting posture in baggage lifting up and putting down could be clearly shown by the analysis using this apparatus. © 1991, Japan Society for Occupational Health. All rights reserved.