Genetically optimized parameter estimation of mathematical model for multijoints hipxe2x80x93knee exoskeleton Abstract   Achieving precise parameters of multijoints actuators for Hipxe2x80x93Knee Exoskeleton (HKE) is a crucial process due to its nonlinear characteristics. In this paper, a Genetic Algorithm (GA) based optimization is used for parameter estimation of the mathematical model for a fourDegree of Freedom (DoF) multijoint HKE, which is a type of Lower Limb Exoskeleton (LLE). Mathematical model for electromechanical, mechanical, and electrical components of the HKE has been formulated, and its parameters are estimated using GA and experimental method. An objective function is determined based on the difference between the simulated and actual angular trajectory for each joint. The performance of the mathematical model is examined with different voltages under the range of 4 V to 8 V for hip and knee, respectively. Furthermore, the performance of the estimated model is compared with Particle Swarm Optimization (PSO). The results and numerical analysis demonstrated that the estimated model by GA and PSO with varying voltages predicted the actual angular trajectory with acceptable error, while GA provides the more accurate model. It can be ascertained that the proposed method of estimation for mathematical model of the HKE is applicable to identify its parameters, and useful for designing a control system.

Design of A Lower Limb Exoskeleton Driven by Tendonsheath Artificial Muscle * In the past decades, with the development of science and technology, lower limb exoskeletons have been developed quickly, which can help patients to walk or do rehabilitation training. In this paper, the design of a lower limb exoskeleton, named SEUEXO, will be presented in detail. The SEUEXO is driven by a new type of artificial muscle, which actuated by a motor and tendonsheath system based on Hill muscle model. In this structure, with a controllable clamper, a series spring and a parallel spring, this artificial muscle can mimics musclexe2x80x99s characteristics, and has better compliance and controllability. Based on the principle of bionics, the degrees of freedom for rehabilitation exoskeleton are allocated reasonably, the mechanical structure is presented, and the tendonsheath transmission path optimization method is studied. Finally, the evaluation experiments are verified, which proves the reliability and stability of the SEUEXO.