  Communication and cooperation among team members can be enhanced
significantly with physical interaction. Successful collaboration requires the
integration of the individual partners' intentions into a shared action plan,
which may involve a continuous negotiation of intentions and roles. This paper
presents an adaptive haptic shared control framework wherein a human driver and
an automation system are physically connected through a motorized steering
wheel. By virtue of haptic feedback, the driver and automation system can
monitor each other actions and can still intuitively express their control
intentions. The objective of this paper is to develop a systematic model for an
automation system that can vary its impedance such that the control authority
can transit between the two agents intuitively and smoothly. To this end, we
defined a cost function that not only ensures the safety of the collaborative
task but also takes account of the assistive behavior of the automation system.
We employed a predictive controller based on modified least square to modulate
the automation system impedance such that the cost function is optimized. The
results demonstrate the significance of the proposed approach for negotiating
the control authority, specifically when humans and automation are in a
non-cooperative mode. Furthermore, the performance of the adaptive haptic
shared control is compared with the traditional fixed automation impedance
haptic shared control paradigm.
