The biomechanical system of the soft exoskeleton glove is studied in this letter. In this context, several aspects have been treated. The delay time model with fractional-order exponent${\boldsymbol{\beta }} = 1.5$for a soft exoskeleton of a patient that suffered a cerebrovascular accident is proposed. The model contains two major elements of uncertainty: the first element is represented by the time delay that corresponds to the reaction time of the human factor and the second element is given by the disturbing muscular torque of the patient's hand. A robust control system is studied to ensure the desired performances of the tracking error relative to a reference position. The stability of the control system is demonstrated by the Lyapunov techniques. The control method and the resulting algorithms are implemented in the research stage of the soft EXOSKELETON-GLOVE (EX-GLOVE) model. The numerical simulations and experimental tests demonstrated the correctness of the proposed solutions.

The paper treats the control problem of a class of hyper-redundant robot constituted by a chain of continuum segments. The technological model basis is a central, long and thin, highly flexible and elastic backbone. The driving system is a decoupled one. The main parameters of the arm control are determined by the curvature and curvature gradient. The dynamic model is inferred. A sliding mode control system is used in order to achieve a desired shape of the arm. The stability of the closed loop control system is proven. Numerical simulations are also provided to verify the effectiveness of the presented approach.

This paper treats the control problem of a class of hyper-redundant robots. The dynamic model of the arm is described by hyperbolic partial differential equations with uncertain components. By using a spatial weighted error control, the infinite dimensional system control becomes a finite-dimensional control problem. The stability analysis and the resulting controllers are obtained using the concept of boundary geometric control and a spatial weighted error control technique. A robust algorithm that is based on weighted error sliding mode control is discussed. The boundary tendon control determines the system evolution toward a prescribed switching surface, and in order to avoid the oscillations around the switching surface, a damping control determines a direct evolution, along the switching surface, toward the origin. Numerical simulations and experimental results are also provided to verify the effectiveness of the presented approach.

The paper focuses on hyper-redundant arms with continuum elements that perform the grasping function by coiling. First, there is concern with the dynamic model of the continuum arm for the position control during non-contact operations with the environment. A frequency stability criterion based on the Kahman - Yakubovich - Popov Lemma and P and PD control algorithms is proposed. Then, the grasping control of the arm in contact with a load is analyzed. The dynamics of the system are discussed and an extension of the Popov criterion is endorsed. The control algorithms based on SMA actuators are introduced. Numerical simulations and experimental results of the arm motion toward an imposed target are presented.

The grasping control problem for a hyperredundant manipulator is presented. The dynamic model is derived by using Lagrange equations developed for infinite dimensional systems. The algorithms for the position and force control are proposed. The arm fluid pressure control is inferred and the conditions that ensure the stability of the motion are discussed. Numerical simulations are presented.

The control problem of a class of tentacle arm, with variable length, that can achieve any position and orientation in 3D space and can increase the length in order to get a better control in the constraint operator space is presented. First, the dynamic model of the system is inferred. In order to avoid the difficulties generated by the complexity of the nonlinear integral - differential model, the control problem is based on the artificial potential method. Then, the method is used for constrained motion in an environment with obstacles. Numerical simulations for spatial and planar tentacle models are presented in order to illustrate the efficiency of the method.

The control problem of the spatial tentacle manipulator with SMA control is presented. The difficulties determined by the complexity of the nonlinear integral-differential equations are avoided by using a very basic energy relationship of this system. A PD controller is discussed and a control coefficient selection procedure is introduced. Numerical simulations for planar and spatial tentacle models are presented and an experimental model is discussed.

The control problem of the spatial tentacle manipulator is presented. The difficulties determined by the complexity of the nonlinear integral-differential equations are avoided by using a very basic energy relationship of this system. Energy-based control laws are introduced by using only the relations that determine the energy stored in the system. A PD controller and a fuzzy controller are discussed. Numerical simulations for spatial and planar tentacle models are presented in order to prove the efficiency of the method.

A hierarchical fuzzy controller with two levels is proposed to solve the control for a multi-chain robotic system formed by tentacle manipulators grasping a common object with hard point contacts. The control system contains two parts: the first component is a conventional controller which implements a control strategy based on the Lyapunov stability, and the second one is an adaptive fuzzy controller which adjusts the control parameters by the output of the first level controller. The stability and robustness is investigated and the fuzzy rules are established. Simulation results are presented and discussed.

A robust control system is proposed to solve the local control for a multi-chain robotic system formed by tentacle manipulators grasping a common object with hard point contacts. The two-level hierarchical control is adopted. The upper level coordinator gathers all the necessary information to resolve the distribution force. Then, the lower-level local control problem is treated as an open-chain redundant manipulator control problem. The stability and robustness of a class of the fuzzy logic control (FLC) are investigated and a robust FLC is proposed with uncertainties of the load. The fuzzy rules are established. Simulation results are presented and discussed.

A control system is proposed to solve the local control for a multi-chain robotic system formed by tentacle manipulators grasping a common object with hard point contacts. The two-level hierarchical control is adopted. The upper level coordinator gathers all the necessary information to resolve the force distribution. The lower-level local control problem is then treated as an open-chain redundant manipulator control problem. A closed loop control based on the inverse dynamic model and the DSMC procedure are proposed. The fuzzy rules are established. Simulation results are presented and discussed.

This paper proposes a new method for multichain hyper-redundant robot models. A hyper-redundant model is a manipulator with a great flexibility-a tentacle model which can achieve any shape in space. We will discuss a system formed by hyper-redundant manipulators grasping a common object with hardpoint control. The two-level hierarchical control is adopted. The upper level coordinator gathers all the necessary information to resolve the force distribution. Then, the lower-level local control problem is treated as a open-chain redundant manipulator control problem. A closed loop control based on the inverse dynamic model and the direct sliding mode control (DSMC) procedure are proposed. The fuzzy rules are established. Simulation results are presented and discussed.

The paper presents a new controller for a tentacle arm based on the viscosity control of the ER-fluids by an electrical field. The dynamic model of the arm is determined and an approximate model is proposed. The motion control is determined as a conventional control of the fluid pressure and as a viscosity control on the switching manifolds. The stability of the motion is proved and the conditions of the trajectory control on the switching manifolds are determined. Two viscosity control procedures are used: a lumped control and a sequential distributed control which allows the decomposition of the system in a finite number of a lower dimension problems. The numerical simulations are presented.

The paper presents a class of tentacle arms based on the use of flexible composite materials in conjunction with active-controllable electrorheological (ER) fluids. The model consists of a finite number of segments, each segment having a specific structure and control. The dynamic behaviour of the arm is obtained using Lagrange's principle developed for infinite-dimensional systems. This model is represented by a set of integral-differential equations. An approximate model is then derived as a set of differential equations with variable coefficients. Two cases are discussed: the sliding mode with the bang-bang control; and the direct mode in which the controller is based on the use of the direct evolution of the system on the switching line by switching the fluid viscosity. The numerical simulations are presented. A nonlinear observer is introduced to estimate the inaccessible state variable distributed on the length of the arm. The conditions which assure the convergence to zero of the errors are proved.