Haptic Feedback Technology For Automotive Terminal Interface

As cars are becoming increasingly intelligent and connected,they have been transformed into mobile multi-media spaces,with a significant increase in the amount of information drivers can access and interact with in the vehicle.Automotive terminal displays are gradually replacing physical controls and integrating more and more configurable functions.However,operating an automotive display with many functions while driving can distract the driver a lot.Traditional automotive terminal interfaces do not integrate haptic feedback technology,so drivers need to look at the screen to find buttons which take their eyes off the road ahead,greatly reducing driving safety.Haptic feedback technology has only been applied to the automotive industry in recent years.Virtual buttons and virtual knobs are the two most important elements of the automotive terminal interface,however,the existing haptic rendering for these two elements is not realistic.Only haptic feedback as a signal of successful virtual button click operation is used,and systematic research on the rendering method of virtual knobs is lacked.Based on the programmable haptic feedback device,this paper investigates the haptic rendering method combining electrostatic force and mechanical vibration for the whole process of interaction between the driver and the virtual knob and button of the automotive terminal interface.On this basis,within-subject repeated measurement experiments are designed to test the effect of implementing programmable search-based haptic feedback force on the automotive terminal interface.The paper uses dynamic and static haptic rendering methods to achieve a more realistic haptic reproduction effect and uses haptic feedback technology for both confirmation and search functions.It is dedicated to solving the driving safety problems caused by the lack of realistic haptic reproduction effect of virtual buttons and knobs that lead to driver distraction due to their manipulation.This paper provides a reference for integrating haptic feedback technology in automotive information systems.The main contributions of this paper are as follows:(1)To achieve the haptic feedback application method in the interaction process with automotive terminal interface,a three-stage haptic representation model including exploration,recognition,and confirmation of virtual buttons and knobs is established,and a haptic rendering method combining electrostatic force and mechanical vibration is proposed.In the exploration stage,both the virtual button and the knob adopt a haptic feedback method with square wave excitation vibration cue;In the recognition stage,the edge-enhanced virtual button haptic rendering method with upward-edge square wave excitation haptic rendering and downward-edge burst excitation haptic rendering,and the virtual knob haptic rendering method based on the angular velocity-frequency mapping model are adopted;In the confirmation stage,a multi-parametric input voltage haptic rendering method and a virtual knob haptic detent are employed.The representation model reflects the haptic characteristics of the physical operation process,making the haptic rendering more realistic and the operation more clear and fast,and realizing the haptic search function.(2)To analyze the effect of haptic feedback on interaction performance,a haptic feedback virtual knob interaction efficiency evaluation model was derived by combining Fitz’s law and Mahalanobis distance,which verified that increasing haptic feedback could reduce clockwise and counterclockwise rotation time by 4.33% and 4.27%,respectively.Based on the programmable haptic feedback device,12 experimenters were selected and the time of the rotation gesture is obtained.A linear regression model was used to verify the linear relationship between the difficulty coefficient and the rotation time.1296 sets of data were analyzed by the two-way repeated measures ANOVA method to conclude that haptic feedback can reduce the rotation interaction time and thus improve the interaction efficiency.And the degree of explanation of the independent variables on the variance of the dependent variable in the fitted linear regression model was 0.807,0.812,0.808 and 0.813,respectively,which is a high degree of explanation and provides a reference for assessing the effect of haptic modality on interaction performance.(3)To address the issue of the effect of haptic feedback on driving behavior,comparative experiments on interaction under visual and auditory feedback were designed and conducted to obtain experimental data of the effect of manipulating the haptic feedback automotive terminal interface on glance behavior,accuracy,driving performance and subjective perception in a virtual driving environment.Based on a programmable haptic feedback device and a driving simulator,15 experimenters were selected to complete specified key operations and 45°,90°,and 180° knob rotation tasks while driving in the simulation.675 sets of objective experimental data were analyzed using one-way and twoway repeated measures ANOVA,and 45 sets of subjective experimental data were analyzed using independent samples t-tests.It was concluded that compared to having only visual feedback,the use of a three-stage virtual key and knob haptic representation model rendering method resulted in a 21.71%,6.25%,and 5.83% reduction in the button task,and29.05%,26.41%,and 6.03% reduction in the 45° knob task,respectively,in terms of total glance time,total glance count,and standard deviation of lane position during simulated driving.And in terms of operation accuracy,the button task improved by 2.39% and the 45°knob task improved by 26.09%.At the same time the experimenter’s pleasure and selfconfidence are improved,the difficulty of completion is reduced,and the driving experience is enhanced.