Transparency analysis of client-server-based multi-rate haptic interaction with deformable objects

In this paper we describe a client-server architecture for haptic interaction with simulated deformable objects. The computationally expensive object deformation is computed on the server at a low temporal update rate and transmitted to the clients. There, an intermediate representation of the deformable object is used to locally render haptic force feedback displayed to the user at the required rate of 1 kHz. Based on a one-dimensional deformable object, we analyze the transparency of this multi-rate architecture for a single client interaction. The delay introduced by the deformation simulation and the client-server communication leads to increased rendered forces at the clients compared to a reference scenario without delay. We propose a method that adaptively adjusts the stiffness used in the local force rendering at the client to compensate for this. The evaluation shows that the proposed method successfully compensates the effect of delay in the tested delay range of up to 100 ms.