Methods Of Sensation Feedback Signal In Prosthetic Interaction

Partial limb loss caused by accident,illness and other factors will bring psychological and physical trauma to amputees.Installation of artificial limb is an effective way to supply for the loss of motor function.The ideal prosthetic control system is a closed-loop control system based on the mode of user→prostheses→user.The existing EMG prostheses have made certain achievements in the research of extracting and decoding EMG signals and achieving stable motion output.When the user’s neural decision-making information is extracted by the artificial limb and completes the corresponding movement,it will interact with the external environment in a series of ways,that is,the "feeling" generated by the healthy human body.Adding feedback to restore feeling in prosthetic design is conducive to users’ control of prosthetic limbs and improve the experience of prosthetic products.The process of transition of information from artificial limb to users should be complete and efficient,in which the feedback signal plays a vital role.Different user groups have different requirements for feedback signals.At present,there is still a lack of a scientific method to determine the appropriate feedback signal.The research of vibration feedback and pressure feedback signals was took as example,this paper proposes a method for selecting appropriate feedback signals for prosthetic products.The specific research contents are as follows.(1)Research on vibration feedback signal: vibration was selected as the feedback signal.The different thresholds of human body were measured under different vibration intensities,simulating the process of amputees using prosthetic limbs to complete their daily work under vibration feedback.In this way the corresponding user data was analyzed.Based on the results,the methods of vibration feedback in prosthetic interaction is proposed: determine the feedback signal,measure the different threshold to vibration,compare the user’s ability to complete tasks under different vibration intensities feedback,then select the appropriate vibration feedback signal.(2)Research on force feedback signal: force was selected as the feedback signal.A series of man-machine experiments were carried out according to the methods proposed in vibration feedback,and multiple criteria to evaluate the experimental results was selected.Different thresholds of human body under different pressure were quantified,the sensitivity to different pressure was compared.The process of users completing tasks with artificial limbs in different pressure ranges was simulated,and psychological data of subjects was collected.This scheme improves the method of sensory feedback in prosthetic interaction,and provides a reference for the selection of pressure feedback signals for prosthetic products.(3)Methods of sensory feedback signals in prosthetic interaction.The research of vibration feedback and force feedback was took as an example,method of selecting the feedback form,measuring the difference thresholds of human body,determining the intensity range of the feedback signal,and selecting the appropriate feedback signal was proposed.It provides quantitative information and scientific basis for the signal selection of the feedback device of prosthetic products,including user sensitivity,the adaptation of human body,and the psychological data of the user body.Designers of prosthetic limbs should select appropriate feedback signals according to their product positioning.After users master the feedback signals through training,they can form perfect closed-loop control when using the prosthetic limbs,so that the prostheses can truly become a part of the body.