Servo-Level Human–Machine Shared Control Flexible Strategy Based on Driving Ability, Status and Regionalized Environmental Risk

The design of interaction strategy between the human driver and automated driving system (ADS) brings great challenges to driving automation. A servo-level human–machine shared control flexible strategy (SHSC-FS) is proposed to solve the problem of how to reasonably allocate driving control authority (DCA—the proportional distribution of outputs from the driver and ADS when they complete the same dynamic driving task at the same time together). The strategy can realize DCA allocation by evaluating whether the driver’s long-term ability and status can cope with the real-time environmental risk from different directions around. Through the verification test and the analysis of the natural vehicle trajectory dataset, it is found that the regionalized environmental risk faced by human drivers during driving obeys normal distribution. The real-time driving abilities (which is defined as driving status here) of human drivers also obey normal distribution. In addition, the verification tests show that SHSC-FS proposed tends to give higher DCA to the drivers with strong driving ability when they are facing low environmental risk from regions where they are sensitive and good at coping; when dealing with the high environmental risk from regions where drivers are insensitive and not good at dealing with, DCA given to the drivers with weak driving ability is lower.