Es. Jung et al., UPPER-BODY REACH POSTURE PREDICTION FOR ERGONOMIC EVALUATION MODELS, International journal of industrial ergonomics, 16(2), 1995, pp. 95-107
Proper assessment of human reach posture is one of the essential funct
ions for ergonomic workspace design and evaluation in computer-aided e
rgonomic evaluation models or any CAD system with a built-in man model
. To predict reach posture, most existing models have been using heuri
stic methods, which provide only the range of feasible postures, not a
lways ensuring the one that a person naturally takes. An analytic reac
h prediction algorithm was developed in this study by employing the in
verse kinematics methods. Each upper limb is modelled as a four-link s
ystem, consisting of trunk, upper arm, lower arm, and hand, being rega
rded as a redundant manipulator with a total of eight degrees of freed
om. Among several kinematic methods for solving human reach movement,
the resolved motion method which is one of the redundant manipulator t
echniques in robotics was found to be effective. In this method, the j
oint range availability was used as a performance function to guarante
e kinematic optimality and to simulate human reach closely. In additio
n, an approximate algorithm to generate the workspaces of human body w
as developed. Real reach postures taken from the subjects were analyze
d by the motion analysis system and were statistically similar to thos
e obtained from the prediction model.