Design And Research Of Fluid Driven Variable Stiffness Haptic Interaction Device

Tactile sense is the unique sensory channel through which humans can transmit energy and information in two directions.As an emerging form of human-computer interaction,for the virtual reality scene with complex task scenes and the pursuit of immersive experience,the haptic interaction device with rigid structure is not flexible enough to adapt to user requirements.With the progress of material science,especially the rapid development of intelligent materials and 3D printing technology,soft actuators with the characteristic of simulating haptic interaction have been applied in different fields,gradually attracting the attention of researchers in the field.Designers can choose different materials according to the intended use of the soft actuator,and realize appropriate deformation and driving mode through structural design,so as to meet the demand for the authenticity of tactile feedback.Firstly,based on the design framework of interactive system,this paper analyzes the advantages of the existing interaction mode based on the handle from the perspectives of people,activities,scenes,technologies,and explores the functional requirements and opportunities of adding haptic interaction on the basis of it.It proposes the conceptual design of virtual reality haptic interaction device,which is the goal of the research on tactile feedback actuators and their driving devices.Secondly,according to the functional requirements of the proposed conceptual design,combined with the bionic design idea,the physiological structure and driving principle of the corpus cavernosum are simulated to complete the design and selection of the hydraulic driving pipeline and the structural design of the tactile feedback actuator.The variable stiffness tactile feedback actuator is fabricated by Stereo lithography Apparatus(SLA)and tested.The molding quality of the variable stiffness actuator and the feasibility of pressure driving after assembling the sealing structure are verified by preliminary pressure testing.Through the loaddisplacement testing,the influence of the sidewall thickness of the cavity and the sealing structure covered by nylon mesh on the working performance of the actuator is analyzed,the appropriate structural design of the variable stiffness actuator is then determined and the variable stiffness actuator that can work stably is finally manufactured.Based on the experience accumulated in the process of design and experiment,the common problems of using Stereo lithography Apparatus in the process of making soft actuators and the influence of printing parameters on the molding quality are analyzed in detail from three aspects,such as model design,model slicing and post-processing,and the advantages and limitations of SLA in making soft actuators are summarized.Thirdly,the functional prototype of the haptic interaction device is designed,including hydraulic pipeline design,circuit design,programming,box design of the hydraulic drive device and functional prototype design of the haptic interaction handle.Load-displacement experiments are carried out under different conditions to test the response relationship between the speed of the centrifugal pump,the angle of the flow limiting valve,the pipeline pressure and the variable stiffness performance of the handle.The results show that the variable stiffness performance of the handle,the pipeline pressure and the rotate speed of the centrifugal pump are all linearly correlated.Under the structural design of the actuator and the design of the driving device,the actuator can achieve a wide range of variable stiffness characteristics and can be stably controlled by controlling the rotate speed of the centrifugal pump,which verifies the feasibility of the technical scheme.Finally,through the pressure response time test,the advantage of hydraulic drive in response speed compared with gas drive is verified,which meets the expected goal of conceptual design.