Exploring planet geology through force-feedback telemanipulation from orbit.

Current space exploration roadmaps envision exploring the surface geology of celestial bodies with robots for both scientific research and in situ resource utilization. In such unstructured, poorly lit, complex, and remote environments, automation is not always possible, and some tasks, such as geological sampling, require direct teleoperation aided by force-feedback (FF). The operator would be on an orbiting spacecraft, and poor bandwidth, high latency, and packet loss from orbit to ground mean that safe, stable, and transparent interaction is a substantial technical challenge. For this scenario, a control method was developed that ensures stability at high delay without reduction in speed or loss of positioning accuracy. At the same time, a new level of safety is achieved not only through FF itself but also through an intrinsic property of the approach preventing hard impacts. On the basis of this method, a tele-exploration scenario was simulated in the Analog-1 experiment with an astronaut on the International Space Station (ISS) using a 6-degree-of-freedom (DoF) FF capable haptic input device to control a mobile robot with manipulator on Earth to collect rock samples. The 6-DoF FF telemanipulation from space was performed at a round-trip communication delay constantly between 770 and 850 milliseconds and an average packet loss of 1.27%. This experiment showcases the feasibility of a complete space exploration scenario via haptic telemanipulation under spaceflight conditions. The results underline the benefits of this control method for safe and accurate interactions and of haptic feedback in general.

A Novel Energy Compensation Scheme for Quality Enhancement in Time-Delayed Teleoperation With Multi-DoF Haptic Data Reduction and Communication.

Efficient and low-delay exchange of hapticinformation plays a key role for the design of high-fidelity teleoperation systems that operate over real-world communication networks. In the presence of communication unreliabilities such as delay and packet loss, a combination of stability-ensuring control schemes and haptic data reduction approaches is essential to address the challenges from both the control and communication perspective. In this paper, we extend our previous one degree-of-freedom (DoF) solution to 3DoF that combines the time-domain passivity approach (TDPA) and the perceptual deadband-based (DB) haptic data reduction approach. We also extend the 1DoF energy compensation (EC) scheme to 3DoF for mitigating the control artifacts introduced by the inter-play of the TDPA and DB approaches. The 3DoF solution is analyzed in detail and verified through a real-world teleoperation setup. The performance of the proposed method and the existing solutions is compared though objective and subjective assessments. Experimental results show that by jointly considering the evaluated objective/subjective quality and the required packet rate, the proposed 3DoF solution with the EC scheme improves system performance significantly compared to the state-of-the-art solutions.

Model-Augmented Haptic Telemanipulation: Concept, Retrospective Overview, and Current Use Cases.

Certain telerobotic applications, including telerobotics in space, pose particularly demanding challenges to both technology and humans. Traditional bilateral telemanipulation approaches often cannot be used in such applications due to technical and physical limitations such as long and varying delays, packet loss, and limited bandwidth, as well as high reliability, precision, and task duration requirements. In order to close this gap, we research model-augmented haptic telemanipulation (MATM) that uses two kinds of models: a remote model that enables shared autonomous functionality of the teleoperated robot, and a local model that aims to generate assistive augmented haptic feedback for the human operator. Several technological methods that form the backbone of the MATM approach have already been successfully demonstrated in accomplished telerobotic space missions. On this basis, we have applied our approach in more recent research to applications in the fields of orbital robotics, telesurgery, caregiving, and telenavigation. In the course of this work, we have advanced specific aspects of the approach that were of particular importance for each respective application, especially shared autonomy, and haptic augmentation. This overview paper discusses the MATM approach in detail, presents the latest research results of the various technologies encompassed within this approach, provides a retrospective of DLR's telerobotic space missions, demonstrates the broad application potential of MATM based on the aforementioned use cases, and outlines lessons learned and open challenges.

Sensorimotor performance and haptic support in simulated weightlessness.

The success of many space missions critically depends on human capabilities and performance. Yet, it is known that sensorimotor performance is degraded under conditions of weightlessness. Therefore, astronauts prepare for their missions in simulated weightlessness under water. In the present study, we investigated sensorimotor performance in simulated weightlessness (induced by shallow water immersion) and whether performance can be improved by choosing appropriate haptic settings of the human-machine interface (e.g., motion damping). Twenty-two participants performed basic aiming and tracking tasks with a force feedback joystick under water and on land and with different haptic settings of the joystick (no haptics, three spring stiffnesses, and two motion dampings). While higher resistive forces should be avoided for rapid aiming tasks in simulated weightlessness, tracking performance is best with higher motions damping in both land and water setups, although the performance losses due to water immersion cannot be compensated. The overall result pattern also provides insights into the causal mechanism behind the slowing effect during aiming motions and decreased accuracy of tracking motions in simulated weightlessness. Findings provide evidence that distorted proprioception due to altered muscle spindle activity seemingly is the main trigger of impaired sensorimotor performance in simulated weightlessness.

Haptic Augmentation for Teleoperation through Virtual Grasping Points.

Future challenges in teleoperation arise from a new complexity of tasks and from constraints in unstructured environments. In industrial applications as nuclear research facilities, the operator has to manipulate large objects whereas medical robotics requires extremely high precision. In the last decades, research optimized the transparency in teleoperation setups through accurate hardware, higher sampling rates, and improved sensor technologies. To further enhance the performance in telemanipulation, the idea of haptic augmentation has been briefly introduced in [Panzirsch et al., IEEE ICRA, 2015, pp. 312-317]. Haptic augmentation provides supportive haptic cues to the operator that promise to ease the task execution and increase the control accuracy. Therefore, an additional haptic interface can be added into the control loop. The present paper introduces the stability analysis of the resulting multilateral framework and equations for multi-DoF coupling and time delay control. Furthermore, a detailed analysis via experiments and a user study is presented. The control structure is designed in the network representation and based on passive modules. Through this passivity-based modular design, a high adaptability to new tasks and setups is achieved. The results of the user study indicate that the bimanual control brings large benefits especially in improving rotational precision.