27 research outputs found
Fixed-time safe tracking control of uncertain high-order nonlinear pure-feedback systems via unified transformation functions
summary:In this paper, a fixed-time safe control problem is investigated for an uncertain high-order nonlinear pure-feedback system with state constraints. A new nonlinear transformation function is firstly proposed to handle both the constrained and unconstrained cases in a unified way. Further, a radial basis function neural network is constructed to approximate the unknown dynamics in the system and a fixed-time dynamic surface control (FDSC) technique is developed to facilitate the fixed-time control design for the uncertain high-order pure-feedback system. Combined with the proposed unified transformation function and the FDSC technique, an adaptive fixed-time control strategy is proposed to guarantee the fixed-time tracking. The novel original results of the paper allow to design the independent unified flexible fixed-time control strategy taking into account the actual possible constraints, either present or missing. Numerical examples are presented to demonstrate the proposed fixed-time tracking control strategy
Feedback Synthesis for Controllable Underactuated Systems using Sequential Second Order Actions
This paper derives nonlinear feedback control synthesis for general control
affine systems using second-order actions---the needle variations of optimal
control---as the basis for choosing each control response to the current state.
A second result of the paper is that the method provably exploits the nonlinear
controllability of a system by virtue of an explicit dependence of the
second-order needle variation on the Lie bracket between vector fields. As a
result, each control decision necessarily decreases the objective when the
system is nonlinearly controllable using first-order Lie brackets. Simulation
results using a differential drive cart, an underactuated kinematic vehicle in
three dimensions, and an underactuated dynamic model of an underwater vehicle
demonstrate that the method finds control solutions when the first-order
analysis is singular. Moreover, the simulated examples demonstrate superior
convergence when compared to synthesis based on first-order needle variations.
Lastly, the underactuated dynamic underwater vehicle model demonstrates the
convergence even in the presence of a velocity field.Comment: 9 page
Design of Sliding Mode PID Controller with Improved reaching laws for Nonlinear Systems
In this thesis, advanced design technique in sliding mode control (SMC) is
presented with focus on PID (Proportional-Integral-Derivative) type Sliding
surfaces based Sliding mode control with improved power rate exponential
reaching law for Non-linear systems using Modified Particle Swarm Optimization
(MPSO). To handle large non-linearities directly, sliding mode controller based
on PID-type sliding surface has been designed in this work, where Integral term
ensures fast finite convergence time. The controller parameter for various
modified structures can be estimated using Modified PSO, which is used as an
offline optimization technique. Various reaching law were implemented leading
to the proposed improved exponential power rate reaching law, which also
improves the finite convergence time. To implement the proposed algorithm,
nonlinear mathematical model has to be decrypted without linearizing, and used
for the simulation purposes. Their performance is studied using simulations to
prove the proposed behavior. The problem of chattering has been overcome by
using boundary method and also second order sliding mode method. PI-type
sliding surface based second order sliding mode controller with PD surface
based SMC compensation is also proposed and implemented. The proposed
algorithms have been analyzed using Lyapunov stability criteria. The robustness
of the method is provided using simulation results including disturbance and
10% variation in system parameters. Finally process control based hardware is
implemented (conical tank system)
Sliding Mode Control
The main objective of this monograph is to present a broad range of well worked out, recent application studies as well as theoretical contributions in the field of sliding mode control system analysis and design. The contributions presented here include new theoretical developments as well as successful applications of variable structure controllers primarily in the field of power electronics, electric drives and motion steering systems. They enrich the current state of the art, and motivate and encourage new ideas and solutions in the sliding mode control area
Industrial Robotics
This book covers a wide range of topics relating to advanced industrial robotics, sensors and automation technologies. Although being highly technical and complex in nature, the papers presented in this book represent some of the latest cutting edge technologies and advancements in industrial robotics technology. This book covers topics such as networking, properties of manipulators, forward and inverse robot arm kinematics, motion path-planning, machine vision and many other practical topics too numerous to list here. The authors and editor of this book wish to inspire people, especially young ones, to get involved with robotic and mechatronic engineering technology and to develop new and exciting practical applications, perhaps using the ideas and concepts presented herein