High-Speed and Low-Power PID Structures for Embedded Applications.

International audienceIn embedded control applications, control-rate and energyconsumption are two critical design issues. This paper presents a series of highspeed and low-power finite-word-length PID controllers based on a new recursive multiplication algorithm. Compared to published results into the same conditions, savings of 431% and 20% are respectively obtained in terms of control-rate and dynamic power consumption. In addition, the new multiplication algorithm generates scalable PID structures that can be tailored to the desired performance and power budget. All PIDs are implemented at RTL level as technology-independent reusable IP-cores. They are reconfigurable according to two compile-time constants: set-point word-length and latency

Design of high-speed and low-power finite-word-length PID controllers.

International audienceASIC or FPGA implementation of a finite word-length PID controller requires a double expertise : in control system and hardware design. In this paper, we only focus on the hardware side of the problem. We show how to design configurable fixed-point PIDs to satisfy application srequiring minimal power consumption, or high control-rate, or both together. As multiply operation is the engine of PID, we experienced three algorithms : Booth, modified Booth, and a new recursive multi-bit multiplication algorithm. This later enables the construction of finely grained PID structures with bit-velvel and unit-time precsion. Such a feature permits to tailor the PID to the desired performance and power budget. All PIDs are emplemented at register-transfer-level (RTL) level as technology-independent reusable IP-cores. They are reconfigurable according to two compile-time constants : set-point word-length and latency. To make PID design easily reproducible, all necessary implementation details are provided and discussed

Cooperative SLAM for multiple UGVs navigation using SVSF filter

The aim of this paper is to present a cooperative simultaneous localization and mapping (CSLAM) solution based on a laser telemeter. The proposed solution gives the opportunity to a group of unmanned ground vehicles (UGVs) to construct a large map and localize themselves without any human intervention. Many solutions proposed to solve this problem, most of them are based on the sequential probabilistic approach, based around Extended Kalman Filter (EKF) or the Rao-Blackwellized particle filter. In our work, we propose a new alternative to avoid these limitations, a novel alternative solution based on the smooth variable structure filter (SVSF) to solve the UGV SLAM problem is proposed. This version of SVSF-SLAM algorithm uses a boundary layer width vector and does not require covariance derivation. The new algorithm has been developed to implement the SVSF filter for CSLAM. Our contribution deals with adapting the SVSF to solve the CSLAM problem for multiple UGVs. The algorithms developed in this work were implemented using a swarm of mobile robots Pioneer 3–AT. Two mapping approaches, point-based and line-based, are implemented and validated experimentally using 2D laser telemeter sensors. Good results are obtained by the Cooperative SVSF-SLAM algorithm compared with the Cooperative EKF-SLAM

Decentralized RBFNN Type-2 Fuzzy Sliding Mode Controller for Robot Manipulator Driven by Artificial Muscles

In the few last years, investigations in neural networks, fuzzy systems and their combinations become attractive research areas for modeling and controlling of uncertain systems. In this paper, we propose a new robust controller based on the integration of a Radial Base Function Neural Network (RBFNN) and an Interval Type-2 Fuzzy Logic (IT2FLC) for robot manipulator actuated by pneumatic artificial muscles (PAM). The proposed approach was synthesized for each joint using Sliding Mode Control (SMC) and named Radial Base Function Neural Network Type-2 Fuzzy Sliding Mode Control (RBFT2FSMC). Several objectives can be accomplished using this control scheme such as: avoiding difficult modeling, attenuating the chattering effect of the SMC, reducing the rules number of the fuzzy control, guaranteeing the stability and the robustness of the system, and finally handling the uncertainties of the system. The proposed control approach is synthesized and the stability of the robot using this controller was analyzed using Lyapunov theory. In order to demonstrate the efficiency of the RBFT2FSMC compared to other control technique, simulations experiments were performed using linear model with parameters uncertainties obtained after identification stage. Results show the superiority of the proposed approach compared to RBFNN Type-1 Fuzzy SMC. Finally, an experimental study of the proposed approach was presented using 2-DOF robot

ACO-Based Optimal MIMO Sliding Mode Controller Design for a New Reconfigurable Unmanned Aerial Vehicle

The Optimized Multiple Inputs and Multiple Outputs Sliding Mode controller (MIMO-SMC) is intended to control the reconfigurable UAV, which can take on a variety of configurations while maintaining the efficiency of a conventional quadrotor in terms of hovering and precision handling. The Ant Colony optimization algorithm is used to calculate controller gains and to ensure optimal performance, such as small errors and lower energy consumption. The control goal is to allow the proposed UAV to track its trajectory for various configurations in the face of uncertain parameters to impose the position, altitude, and yaw angle while stabilizing its roll and pitch angles. Finally, simulation results are used to demonstrate the efficiency and performance of the proposed controller, and we calculate the energy consumption for each configuration

Robust continuous third-order finite time sliding mode controllers for exoskeleton robot

In this work, continuous third-order sliding mode controllers are presented to control a five degrees-of-freedom (5-DOF) exoskeleton robot. This latter is used in physiotherapy rehabilitation of upper extremities. The aspiration is to assist the movements of patients with severe motor limitations. The control objective is then to design adept controllers to follow desired trajectories smoothly and precisely. Accordingly, it is proposed, in this work, a class of homogeneous algorithms of sliding modes having finite-time convergence properties of the states. They provide continuous control signals and are robust regardless of non-modeled dynamics, uncertainties and external disturbances. A comparative study with a robust finite-time sliding mode controller proposed in literature is performed. Simulations are accomplished to investigate the efficacy of these algorithms and the obtained results are analyzed

Adaptive High Order Sliding Mode Observer of Linear Induction Motor

International audienceThis paper presents a novel adaptive high order sliding mode method for linear induction motor (LIM) to reconstruct the states (currents and fluxes), speed and speed-depended parameter w, only using the measured stator voltages and stator currents. The adaptive law is designed to estimate speed and speed-depended parameter w, and their stability have been proved with Lyapunov's theory. Then the estimated values ∧v,∧w are rejected into higher order sliding mode observer (HOSMO). Super twisting algorithm (STA), with its obvious advantage, is applied into HOSMO. Finally, simulation results validated the performance of the proposed adaptive HOSMO scheme

Nonlinear Feedback Super Twisting Field Oriented Control of Linear Induction Motors Considering Dynamic End Effects

International audienceThis paper proposes a nonlinear feedback super twisting field oriented control (NSTC) technique for linear induction motors (LIMs), taking into consideration the dynamic end effects. The state space equation of LIM is given based on Ducan's model. Based on the knowledge of indirect field oriented control (IFOC) theory, a nonlinear feedback super twisting controller is designed to achieve speed and flux tracking, regardless of external disturbances. Simulation results show that the the proposed NSTC scheme has good tracking performance and robustness property with external disturbances

Stabilisation of perturbed chains of integrators using Lyapunov-based homogeneous controllers

International audienceIn this paper, we present a Lyapunov-based homogeneous controller for the stabilisation of a perturbed chain of integrators of arbitrary order r >= 1. The proposed controller is based on homogeneous controller for stabilisation of pure chain of integrators. The control of homogeneity degree is also introduced and various controllers are designed using this concept, namely a bounded-controller with minimum amplitude of discontinuous control and a controller with globally fixed-time convergence. The performance of the controller is validated through simulations

Homogeneous Finite Time Higher Order Sliding Mode Control Applied to an Upper Limb Exoskeleton Robot

International audienceA homogeneous continuous sliding mode control scheme based on finite time stability is developed in this paper for an upper limb exoskeleton robot dedicated for rehabilitation. Indeed this type of robot interacts directly with human limbs whose dynamics are unknown and different for users. Therefore, the main idea is to provide a robust motion control of the exoskeleton robot using a continuous higher order sliding mode controller despite parameters variations, uncertainties and external disturbances. The proposed controller combines the homogeneity concept and the super-twisting algorithm. Finite time stabilization is achieved using the first part of the controller while disturbance rejection is granted by the second part of the controller. Performance of the controller and its robustness are illustrated through simulations of trajectory tracking tests corresponding to passive rehabilitation exercises