FAST USER ACTIVITY PHASE RECOGNITION FOR THE SAFETY OF TRANSFEMORAL PROSTHESIS CONTROL

Abstract

In the process of creating powered transfemoral prostheses, one of the most important tasks is the provision of the user safety while walking. Experience shows that security depends not only on the mechanical strength of such devices, but also on the quality of their control systems, which, among other things, must ensure that latency and error rates of recognition are acceptable for each of the possible changes in gait. Incorrect or late recognition of the activity mode at best can lead to suboptimal assistance from the auxiliary device, and at worst - to loss of stability of the user with a subsequent fall. Loss of stability can also occur due to exceeding the critical time or critical errors of the activity phase recognition and the associated incorrect commands generated by the control system. In this paper, a method for quickly recognizing the phase of the user's activity based on the properties of Hu’s moment invariants is substantiated. Its use in the intelligent control systems will minimize the critical errors that contribute to the loss of the user's equilibrium with the powered transfemoral prosthesis.