WE-Filter: Adaptive Acceptance Criteria for Filter-based Shared Autonomy

Filter-based shared control aims to accept and augment an operator's ability to control a robot. Current solutions accept actions based on their direction aligning with the robot's optimal policy. These strategies reject a human's small corrective actions if they conflict with the robot's direction and accept too aggressive actions as long as they are consistent with the robot's direction. Such strategies may cause task failures and the operator's feeling of loss of control. To close the gap, we propose WE-Filter, which has flexible, adaptive criteria allowing the operator's small corrective actions and tempering too aggressive ones. Inspired by classical work-energy impact problems between two dynamic, interactive bodies, both inputs' properties (direction and magnitude) are inherently considered, creating intuitive, adaptive bounds to accept sensible actions. The model identifies behaviors before and after impact. The rationale is that each timestep of shared control acts as an impact between the operator's and the robot's policies, where post-impact behaviors depend on their previous behaviors. As time continues, a series of impacts occur. The aim is to minimize impacts that occur to reach an agreement faster and reduce strong reactionary behaviors. Our model determines flexible acceptance criteria to bound a mismatch of magnitude and finds a replacement action for conflicting policies. The WE-Filter achieves better task performance, the ratio of accepted actions, and action similarity than the existing methods.