This article presents a holistic approach to engineer the artificial skin for robots with an example of a multimodal skin cell showing multiple humanlike sensing modalities.

In this article, we propose a control method, providing mobile robots with whole-body compliance capabilities, in response to multi-contact physical interactions with their environment. The external forces applied to the robot, as well as their localization on its kinematic tree, are measured using a multimodal, self-configuring and self-calibrating artificial skin. We formulate a compliance control law in Cartesian space, as a set of quadratic optimization problems, solved in parallel for each limb involved in the interaction process. This specific formulation makes it possible to determine the torque commands required to generate the desired reactive behaviors, while taking the robot kinematic and dynamic constraints into account. When a given limb fails to produce the desired compliant behavior, the generalized force residual at the considered contact points is propagated to a parent limb in order to be adequately compensated. Hence, the robot's compliance range can be extended in a both robust and easily adjustable manner. The experiments performed on a dual-arm velocity-controlled mobile manipulator, show that our methodology is robust to nullspace interactions and robot physical constraints.

Abstract-In this paper, we address the issue of wholebody compliance with hierarchical force propagation for omnidirectional mobile manipulators. Using the multimodal tactile feedback (force and proximity) provided by an artificial skin, our objective is to generate prioritized compliant behaviors in response to multicontact physical interactions between a mobile robot and its external environment. To be more specific the force components which cannot be properly propagated using upper-limbs must be projected onto the mobile base in order to generate suitable compliant motions. Using Quadratic Programming (QP), we propose a general method allowing to properly estimate and propagate these force components while respecting the robot physical constraints. In this way, robust whole-body compliance can be achieved. We finally test and validate our method on a complex robotic system.