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The ability to determine whether a robot's grasp has a high chance of failing, before it actually does, can save significant time and avoid failures by planning for re-grasping or changing the strategy for that special case. Machine Learning (ML) offers one way to learn to predict grasp failure from historic data consisting of a robot's attempted grasps alongside labels of the success or failure. Unfortunately, most powerful ML models are black-box models that do not explain the reasons behind their predictions. In this paper, we investigate how ML can be used to predict robot grasp failure and study the tradeoff between accuracy and interpretability by comparing interpretable (white box) ML models that are inherently explainable with more accurate black box ML models that are inherently opaque. Our results show that one does not necessarily have to compromise accuracy for interpretability if we use an explanation generation method, such as Shapley Additive explanations (SHAP), to add explainability to the accurate predictions made by black box models. An explanation of a predicted fault can lead to an efficient choice of corrective action in the robot's design that can be taken to avoid future failures. 

Robot-assisted healthcare could help alleviate the shortage of nursing staff in hospitals and is a potential solution to assist with safe patient handling and mobility. In an attempt to off-load some of the physically-demanding tasks and automate mundane duties of overburdened nurses, we have developed the Adaptive Robotic Nursing Assistant (ARNA), which is a custom-built omnidirectional mobile platform with a 6-DoF robotic manipulator and a force sensitive walking handlebar. In this paper, we present a robot-specific neuroadaptive controller (NAC) for ARNA’s mobile base that employs online learning to estimate the robot’s unknown dynamic model and nonlinearities. This control scheme relies on an inner-loop torque controller and features convergence with Lyapunov stability guarantees. The NAC forces the robot to emulate a mechanical system with prescribed admittance characteristics during patient walking exercises and bed moving tasks. The proposed admittance controller is implemented on a model of the robot in a Gazebo-ROS simulation environment, and its effectiveness is investigated in terms of online learning of robot dynamics as well as sensitivity to payload variations.