A survey of environment-, operator-, and task-adapted controllers for teleoperation systems

Bilateral haptic teleoperation systems allow humans to perform complex tasks in a remote or inaccessible environment, while providing haptic feedback to the human operator. The incorporation of online gained environment-, operator-, or task-specific (EOT) information in the controller structure can lead to significant improvements in robustness, task performance, feeling of presence, or fidelity without compromising stability. This article provides a classification as well as a survey of approaches, called EOT-adapted controllers, which have been developed in this area. A discussion of improvements and requirements is provided for each method. The performed analysis indicates that several methods require the usage of additional sensors or are based on accurate model assumptions. The benefit of EOT-adapted controllers is mostly application-dependent, as each method focuses on the improvement of a specific aspect like coping with time delay or avoiding forbidden regions.