Mohammed Benbrahim

Sliding Mode with Time Delay Control for MIMO nonlinear Systems With unknown dynamics

In this paper, the control problem of Multi-Input Multi-Output (MIMO) nonlinear Systems with unknown dynamics is proposed. A novel method based on the Sliding Mode with Time Delay Control (SMTDC) is proposed by combining a Sliding Mode Control (SMC) with saturation (sat) function and Time Delay Control (TDC). This method (SMTDC), allows chattering reduction on control inputs and estimates the amounts of unknown or unmodeled nonlinear dynamics and unexpected uncertainties and cancels them. This algorithm was simulated on the model of the ANAT robot arm system to demonstrate the effectiveness of the proposed design method.

Control of Uncertain Robot Manipulators using Integral Backstepping and Time Delay Estimation

In this paper, a novel controller is proposed and applied for high accuracy tracking trajectory in the workspace of robot manipulators in presence of uncertainties and external disturbances. Most of nonlinear controllers are based on the mathematical model of robot manipulator, but a lot of robotic systems do not have exact model. This novel approach which consists on designing an Integral Backstepping with Time Delay Control (IBTDC) can estimate uncertainties and keep high tracking performance. The proposed controller is able to stabilize the robot system, and also to drive the trajectory tracking errors to converge in finite time. Furthermore, experimental results are given to illustrate the effectiveness of the proposed method applied to the 7-DOF ANAT robot arm.

Sliding Mode with Time Delay Control for Robot Manipulators

This chapter introduces two controllers design for the trajectory tracking of robot manipulators with unknown dynamics and external disturbances, including: First Order Sliding Mode with Time Delay Control (FOSMTDC), Second Order Sliding Mode with Time Delay Control (SOSMTDC).

Optimal posture prediction of human lower limb

In this paper, a new posture prediction method is proposed and evaluated on human leg, as being a physiologically constrained three-link arm. The main posture prediction solution is focused on optimizing the manipulability and the human performance of the leg. The forward kinematics is used to define the feasible workspace of the human leg in sagittal plane. Using an effective optimization-based human performance measure that incorporates a new objective function of musculoskeletal discomfort, the optimal posture is obtained.

Optimal 3D Kinematic Analysis for Human Lower Limb Rehabilitation.

The majority of the kinematics analysis carried out on the human body are usually available only for use in the sagittal plane. Limited studies were interested in this analysis in all three planes (sagittal, transverse, and frontal) where motions of all joints occur. The aim of this paper is to develop a new optimal kinematic analysis of human lower limbs in threedimensional space for a rehabilitation end. The proposed approach is focused on optimizing the manipulability and the human performance of the human leg, as being a physiologically constrained three-link arm. The obtained forward kinematic model leads to define the feasible workspace of the human leg in the considered configuration. Using an effective optimization-based human performance measure that incorporates a new objective function of musculoskeletal discomfort, the optimal inverse kinematic (IK) model is obtained.

Sensor Fault Detection and Isolation for a Robot Manipulator Based on High-Gain Observers

This paper deals with the analysis and design of a fault detection and isolation scheme (FDI) for a class of affine nonlinear systems using high gain observers. The observers are applied for robot manipulator especially robot named Articulated Nimble Adaptable Trunk “ANAT” in order to detected and isoleted sensor fault. The simulations results prove the effectiveness, performances and the robustness of the approach.

Second order sliding mode with time delay control for uncertain robot manipulators

This paper proposes a second order sliding mode combined with time delay controller to track a desired trajectory for robot manipulators with unknown dynamics and external disturbances. The motivation for using second order sliding mode (SOSM) mainly relies on its appreciable features, such as high precision and elimination of chattering in addition that it ensures robustness. However, the SOSM problem is that the unknown dynamics and the disturbances may be amplified, which makes the system unstable. Then, using the time delay allows to benefit from the robustness of the second order sliding mode while reducing its major drawback. The stability and the robustness of the proposed controller is verified by using the classical Lyapunov criterion. The proposed controller is implemented in real time on the seven-degrees-of-freedom (7-DOF) ANAT robot arm and compared with the sliding mode with time delay control (SMTDC) to prove its superiority.