The necessary conditions of the scaling ratio in master-slave systems based on Human Difference limen of force sense

In the use of master-slave systems designed ignoring human perception abilities, there are threats of missing or misunderstanding important information because the range of the displayed information may be unsuitable for the perception abilities of the operator. Therefore, we aim at incorporating human perception abilities into the necessary conditions for designing the scaling methods in master-slave systems. This work focuses on one of the inner characteristics of force perception, namely the difference limen. Taking account of the well-known Weber's law, we assume that the difference limen is described as a linear function of the standard stimulus. Then, in general, we derive the necessary conditions of scaling methods to recognize changes of stimuli generated on the slave side. Simultaneously, the lower limit of the scaling ratio is clarified. The difference limen at fingertips is measured for constant, elastic, and viscous forces, which are typical force elements. The obtained measurement results confirm the previous assumption of linear dependency. Finally, we conclude with discussions of the necessary conditions based on the measurement data with variations.