A ‘Speed—Difficulty—Accuracy’ Model Following a General Trajectory Motor Task with Spatial Constraints: An Information-Based Model

Salvatore Digiesi,Carlotta Mummolo,Andrea Lucchese

doi:10.3390/app10217516

Salvatore Digiesi, Carlotta Mummolo + Show 1 more

Open Access

https://doi.org/10.3390/app10217516

Copy DOI

Abstract

Accuracy in executing a motor task, i.e., in following a given trajectory under geometrical constraints, is of great interest in work operations as well as in biomechanics applications. In the framework of the Fitts’ law research on motor tasks, experimental studies usually refer to simple trajectories which are of low interest in practical applications. Furthermore, available models lack predicting accuracy in executing motor tasks since do not systematically investigate effects of both speed and task difficulty (index of difficulty (ID)). In this paper, the authors propose a ‘Speed-ID-Accuracy’ model aiming at overcoming abovementioned limits. The model is of general validity as is based on an information-based formulation of a trajectory ID; the model proposed put into relation accuracy in task execution with a general trajectory and with the speed of task execution. Modeling accuracy, defined as standard deviation of the endpoint position, is carried out by regressing data available in the literature. The model proposed proves to be more accurate than the classical ‘Speed-Accuracy’ model in fitting available data. Such a result has been found in both numerical cases relating to ‘tunnel’ and ‘circular’ traveling tasks. Limits of data from field experiments are stressed out and future research field of investigations in work environment and biomechanics are figured out.

Highlights

Investigations on human motor tasks is a wide and interdisciplinary field of research with application in human factors, human-computer-interface, robotics, and biomechanics for rehabilitation, to mention a few
We propose to extend the ‘Speed-Accuracy’ tradeoff model (4) by considering the standard deviation of the endpoint position depending on both speed and Index of Difficult (ID) as: Z
The need for quantifying the accuracy of individuals in executing reaching motor tasks of different difficulty is a problem of relevant importance in different human activities

Summary

Introduction

Investigations on human motor tasks is a wide and interdisciplinary field of research with application in human factors, human-computer-interface, robotics, and biomechanics for rehabilitation, to mention a few. Measuring the accuracy in following a trajectory is crucial in biomechanical applications to assess, for example, the effectiveness of the rehabilitation programs. Modeling human motor tasks generally refers to classical studies most of them considering the well-known Fitts’ law [1]. Some authors improved the findings of the Fitts’ experience by investigating its applicability in control theory [2,3,4] or in estimating psychomotor movement delays [5,6] by computer modeling of the physical environment [7] as well as by virtual reality devices [8]

Results

Discussion

Conclusion