Rate control based on queuing state observer for visual-haptic communication

Recently visual-haptic communication has been attracted attention. From the viewpoint of visual communication, a high packet-sending rate is required to achieve a high control performance. However, a high packet-sending rate often causes a buffer overflow in a queue of a communication device. Because the buffer overflow induces a long communication delay, a haptic communication system becomes unstable as a consequence. This paper therefore proposes a Queuing State Observer which estimates a packet-processing rate of a communication device in real time. The estimated packet-processing rate is applied to a rate controller which selects a suitable packet-sending rate. Because the rate controller achieves both of a high packet-sending rate and a short communication delay, a control performance of visual-haptic communication is improved. The validity of the proposed algorithm is confirmed by experiments.