Study On The Vibrotactile Displays System Of Take-over Requests For Automated Driving

As autonomous vehicles technology is getting developed gradually,autonomous vehicles have emerged in people’s lives,among which have gradually taken into account these problems such as safety and user experience.According to its definition,in the context of highly autonomous vehicles,the driver requires to restore control of the car when the automated system is encountered with traffic conditions that cannot be dealt with.However,the driver should not have monitored the automation process for a long time,but carry out non-driving related tasks during his driving.In this way,the visual and auditory channels are easily occupied,which gives rise to missing takeover request.As tactile displays technology progresses remarkably,tactile channel warning is increasingly becoming a new solution to occupied visual and auditory channels.This paper has a systematic analysis on automatic takeover,tactile display and automobile seat pressure technology.As a result,the seat cushion in vehicles is proposed to be used as a carrier of the tactile display system.The car cushion design is also carried out.Under the guidance of theoretical research,user experience and cognitive factors are studied and summarized in this paper.It draws a conclusion on situation characteristics and human factors of autonomous vehicles takeover.In addition,based on theory study,it designs and develops a tactile display system and moreover it develops a driving simulation system for automatic vehicles innovatively by using Unity 3D engine and hardware equipment of simulation driving.In order to verify the tactile display strategy applied in autonomous vehicles takeover system,based on the actual conditions of driving vehicles on road,this paper makes a systematic analysis on the evaluation of auto vibration and the reaction time for tactile display.As a result,two perfect strategies for takeover request such as layered vibration alert and directional vibration alert in an optimum frequency and amplitude are concluded theoretically in the end.At the same time,under the simulated conditions of autonomous vehicle system,both of them are tested practically in their availabilities.In addition,it also has a study on the influence of vibration alerts on multichannel warnings.According to this experimental result,it is shown that layered vibration alert is able to improve risk perception and takeover performance,but there is no obvious evidence that it has a significant impact on user experience.Which directional vibration alert are capable of improving takeover performance and user experience,but there is no obvious evidence that it has a great influence on risk perception.However,after combining visual and auditory channel warnings with tactile channel warnings,takeover performance,risk perception and user experience are significantly enhanced as a matter of fact.Finally,a tactile display takeover system for autonomous vehicles is designed and evaluated in this study by a usability test.The test showed that tactile display system can significantly improve takeover performance,user experience and risk perception.