Transfemoral Prostheses Control in a Frame of Intellectual-Synergetic Concept

Abstract

Abstract-In the control process of transfemoral prostheses in real time, the need to solve a number of non-trivial tasks there arises. The most difficult of them: recognizing the intentions of the disabled person to carry out any movement in the short term and choosing the optimal strategy for moving to the target, taking into account excessive number degrees of freedom of the prosthetic system. At the same time, the optimal should be considered the strategy of movement, which ensures the safety and most comfortable walking of a disabled person from its subjective point of view. Such a strategy can be implemented in a frame of the intellectual-synergistic concept of control. Herewith, the prosthesis control system is designed based on two basic subsystems: the intellectual subsystem -designed to assess the current state and recognize the intentions of the disabled person and the synergetic subsystem -designed to select the optimal strategy for limb movement toward the goal. In this work, the structure of the transfemoral prosthesis control system, realized within the framework of the intellectual-synergistic concept with regard to synergistic quality criteria, is substantiated. It is shown that the use of reasonable synergetic quality criteria allows successfully solving the pseudo-Bernstein problem when planning the movements of controlled transfemoral prostheses and using these movements as reference for the prostheses control system.

Fast User Activity Phase Recognition for the Safety of Transfemoral Prosthesis Control

“…Reference [1] presents general considerations for the synthesis of ICS for powered TFP in the framework of the Intellectual-Synergetic Concept (ISC). As in most modern ICSs, the ISC-based control system provides three-tier architecture, including the high level controllers (HLC), middle level controllers (MLC) and low level controllers (LLC) [2].…”

“…The basic idea of ISC is that the ICS created on its basis consists of two subsystems: intellectual (IS = HLC + MLC) and synergetic (SS = MLC + LLC). At the same time, IS is responsible for recognizing the locomotor and non-locomotor intentions of the user in the short and medium term, and SS is for their bio-like implementation [1,3]. In principle, as noted in the review [4], controllers of such ICS can perform their functions using different algorithms, each of which can be optimal from the point of view of different criteria and conditions.…”

“…In addition to providing security, the qualitative recognition of the activity phase in IS is important for the reliable determination of the boundary conditions of the problem of planning the bio-like movements of TFP elements in SS [1]. It is known that most ICS to achieve these goals use information about the detected activity in HLC mode and the current state of the device determined using sensors installed in the device or directly in the user [4].…”

“…It is known that most ICS to achieve these goals use information about the detected activity in HLC mode and the current state of the device determined using sensors installed in the device or directly in the user [4]. But such an approach does not allow direct solving of the problem of planning synergetically optimal (bio-like) motions, even under condition of qualitative recognition of the activity mode because it does not provide information about the time remaining before the end of this activity mode [1]. Consequently, the use of the fast phase activity recognition algorithm in IS will allow increasing the quality of planning the movements of TFP elements not only for realization of typical periodic modes of activity but also in the process of volitional control of powered TFP.…”