Comparative Analysis of the Exoskeleton Control Algorithms with the Links of a Variable Length

On Mathematical Modeling of the Dynamics of Multilink Systems and Exoskeletons

“…A significant number of publications are devoted to modeling the dynamics of systems for various purposes and the construction of control algorithms, of which we mention, for example, the works [42][43][44][45][46][47][48][49][50][51][52][53][54][55]. In [56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71][72], various algorithms are proposed for compiling differential equations of motion for exoskeletons, anthropomorphic mechanisms, and rod systems, including systems with variable link lengths. The questions of controlling such systems are investigated.…”

“…The differential equations of motion of the link of variable length in three-dimensional space are described by the Lagrange equations: In general, the model of the human musculoskeletal system contains points with branching, for example, points of connection with the body of the supporting leg, the transferred leg, and the arm. In [67], equations of the dynamics of models with branch points are given. The dynamics of system n's links of variable length, shown in Fig.…”

“…When compiling the Lagrange equations, 0.59 seconds were spent for the model with one moving link; 5.3, with two moving link; and 37, with three moving links. When using the matrix method, it took, respectively, 0.46, 0.55, and 0.79 s [67]. The recurrent algorithm for the model with two and three moving links took 0.59 and 0.86 s. Compared to three-dimensional models, for a model of an exoskeleton with two movable links (Fig.…”

“…Further, the multilink models composed of such links were studied, systems of differential equations of motion were obtained in a generalized vectormatrix form, and a recurrent method for composing systems of differential equations of motion was implemented for them. The mathematical modeling of the movement of exoskeletons and anthropomorphic robots was carried out using the developed models of links of variable length [57,[59][60][61][62][63][64][65][66][67][68][69][70][71].…”