An Intent-Preserving Approach to Telerobotic Rehabilitation

Often the design of control systems for telerobotic rehabilitation focuses on maintaining stability and maximizing transparency, but does not consider the intent of therapeutic interactions. When therapists assist patients during therapy activities, they tailor the amount of assistance and guidance delivered so that the patient engages fully in the therapy. Existing telerobotic control systems deliver the delayed therapist force to the patient, making only minimal changes as necessary to maintain stability. However, communication time delays can distort the effect of the therapist force and lead to remote interactions that do not reflect the therapist’s intent, such as over- or under-assisting the patient. In this work, we propose a method for identifying the therapist’s intent from their applied force and the velocity of the patient. Using this understanding of intent, we propose two approaches to ensure that the therapist’s intent is preserved across the communication channel: Rotational Intent-Preserving Teleoperation (RIPT), where the delayed force from the therapist is rotated to maintain the intended amount of assistance and guidance, and scaled-RIPT, where less relevant forces are reduced. We test these approaches in simulations, finding that they can prevent unintended over-assistance from the therapist.