Control strategies for robot‐assisted telerehabilitation under communication delay: A survey

Abstract Robot‐assisted telerehabilitation systems have recently garnered significant attention within the robotics community, largely due to the effectiveness of master‐slave bilateral teleoperation in delivering rehabilitation therapy. These systems facilitate real‐time physical interaction between therapists and patients remotely through interconnected robotic manipulators. The growing demand for such remote solutions stems not only from a shortage of therapists and limited access to clinical facilities, but was further underscored by the COVID‐19 pandemic, which emphasized the need for tele‐systems capable of maintaining continuous rehabilitation services during lockdowns and social distancing. However, communication time delays, primarily caused by data transmission over the internet or wireless networks, remain a major obstacle to achieving optimal system performance, safety, and user experience. This paper presents a review focused on the impact of communication delay in bilaterally controlled robotic systems for telerehabilitation. We begin by introducing the general architecture of a typical telerehabilitation system, followed by an in‐depth discussion of how delays affect robotic performance and control. We then examine recent advancements in control strategies designed to mitigate these delays. The survey paper highlights key achievements, identifies persistent challenges, and outlines future research directions for developing robust, delay‐tolerant telerehabilitation systems.