A Study on Differences in Control Performance of Skill-Assist System Caused by Different Operational Input Devices

In the social context of aging and shortage of workforce at manufacturing sectors, we are developing "Skill-Assist Light," an assist system for transporting heavyweight products. While a typical power assist system uses a force sensor as an input device, Skill-Assist Light uses an accelerometer instead of a force sensor. The control performance of the method using acceleration, applied in this paper, has not been intensively discussed in previous researches on force sensor-less assist control systems. In this paper, we discuss differences in control performance between the power assist system equipped with a force sensor and that with an accelerometer. First, the differences of these systems are theoretically represented in their dynamic equations of motion. Second, band-pass filters are designed for each system. Finally, we conducted a transporting experiment and showed that there was a possibility that the accelerometer power assist system exhibited behavior that caused different performance from the intended one due to a phase delay originated from low-pass filtered input signals.