Soft robots can revolutionize several applications with high demands on dexterity and safety. When operating these systems, real-time estimation and control require fast and accurate models. However, prediction with first-principles (FP) models is slow, and learned black-box models have poor generalizability. Physics-informed machine learning offers excellent advantages here, but it is currently limited to simple, often simulated systems without considering changes after training. We propose physics-informed neural networks (PINNs) for articulated soft robots (ASRs) with a focus on data efficiency. The amount of expensive real-world training data is reduced to a minimum — one dataset in one system domain. Two hours of data in different domains are used for a comparison against two gold-standard approaches: In contrast to a recurrent neural network, the PINN provides a high generalizability. The prediction speed of an accurate FP model is exceeded with the PINN by up to a factor of 467 at slightly reduced accuracy. This enables nonlinear model predictive control (MPC) of a pneumatic ASR. Accurate position tracking with the MPC running at 47 Hz is achieved in six dynamic experiments.

Using compliant materials leads to continuum robots undergoing large deformations. Their nonlinear behavior motivates the use of model-based controllers. They require state estimation as an essential step to be deployed. Available sensors are usually realized by introducing rigid bodies to the soft robot or inserting soft sensors made of materials different from the robot itself. Both approaches result in changes in the system’s dynamics. Optical measurements are problematic, especially in confined spaces. This can be avoided when the sensor is located at the robot's base. This paper studies the state estimation of a pneumatically actuated soft robot using the measured forces and torques at its base. For the first time, this is done using an unscented Kalman filter without restraining the dynamics to a planar or quasi-static motion while applying it to a real system. Real-time capability is achieved with our implementation. The state estimation is tested in a Cosserat rod simulation and on the physical system. The position is estimated with an accuracy of three to five millimeters for a 130 millimeter long pneumatic robot.

For the development of advanced driver assistance systems (ADAS) and autonomous driving, a perception of the vehicle’s environment is necessary. This includes, among others, road gradients, cross-slopes, and the road surface condition, with the maximum friction coefficient of the tire-road contact as a safety-relevant parameter. However, these three road parameters cannot be measured directly while driving by sensors installed in modern vehicles. Current estimation methods provide either the maximum friction coefficient or the road gradient and cross-slope but never combined. Since the road angles influence the maximum friction coefficient estimation and vice versa, separate estimation of these parameters, in general, leads to incorrect estimation results. In this paper, a new Unscented Kalman Filter (UKF)-based approach is proposed for simultaneous estimation of all three mentioned road parameters. For this purpose, a dynamic vehicle model considering road gradients and cross-slopes is introduced and integrated into the UKF. It is demonstrated that, in contrast to a state-of-the-art UKF, the proposed algorithm yields improved accuracy and correct maximum friction coefficient estimates even on roads with gradients or cross-slopes.

This work presents a semantic map management approach for various environments by triggering multiple maps with different simultaneous localization and mapping (SLAM) configurations. A modular map structure allows to add, modify or delete maps without influencing other maps of different areas. The hierarchy level of our algorithm is above the utilized SLAM method. Evaluating laser scan data (e.g. the detection of passing a doorway) triggers a new map, automatically choosing the appropriate SLAM configuration from a manually predefined list. Single independent maps are connected by link-points, which are located in an overlapping zone of both maps, enabling global navigation over several maps. Loop- closures between maps are detected by an appearance-based method, using feature matching and iterative closest point (ICP) registration between point clouds. Based on the arrangement of maps and link-points, a topological graph is extracted for navigation purpose and tracking the global robot's position over several maps. Our approach is evaluated by mapping a university campus with multiple indoor and outdoor areas and abstracting a metrical-topological graph. It is compared to a single map running with different SLAM configurations. Our approach enhances the overall map quality compared to the single map approaches by automatically choosing predefined SLAM configurations for different environmental setups.