An Effect of Acceleration on Passively-Changed Arm-Velocity Perception

In recent years, the methods of motor learning using haptic devices that can give motion-related stimuli to learners have been studied. In order to design control systems of the haptic devices that can give learners stimuli so that they can perceive them with proprioception, we need to understand the characteristics of human’s position and velocity sensations. Then, in this study, we examined velocity JNDs (Just Noticeable Differences), in order to understand human velocity-change perception. We, in particular, focused on an effect of acceleration during velocity-change to human velocity-change perception. In the experiment, we enforced subjects to accelerate their hands with a constant acceleration of 1, 8, 16, 32 deg/s² from before-acceleration velocity of 10 deg/s. Subjects answered whether they perceived velocity-change or not, and we measured velocity JNDs. As a result, it was found that, while the accelerations increased by 32 times, the velocity JNDs decreased by only about 1/2, i.e., from 8.1 to 4.2 deg/s. From this result, it was concluded that the magnitude of acceleration is not a determinative factor for velocity-change perception but a supplementary one.