Nonlinear Control for Trajectory Tracking of a Nonholonomic RC-Hovercraft with Discrete Inputs

Abstract

This work studies the problem of trajectory tracking for an underactuated RC-hovercraft, the control of which must be done by means of discrete inputs. Thus, the aim is to control a vehicle with very simple propellers that produce only a discrete set of control commands, and with minimal information about the dynamics of the actuators. The control problem is approached as a cascade control problem, where the outer loop stabilizes the position error, and the inner loop stabilizes the orientation of the vehicle. Stability of the controller is theoretically demonstrated and the robustness of the control law against disturbances and noise is established. Simulation examples and experiments on a real setup validate the control law showing the real system to be robust against disturbances, noise, and outdated dynamics.

Improved Genetic Algorithm Tuning Controller Design for Autonomous Hovercraft

“…The autonomous hovercraft simulation parameters were derived from [28][29][30][31] and denoted with the mass m = 2.1 kg and the inertia moment I = 0.000257 kg.m 2 . The modified GA had the mutation rate (Rm) of 0.08, the crossover rate (Rc) of 0.95, and one hundred individuals (n = 100).…”

“…A hovercraft, which is known as an underactuated system and named an air cushion vehicle (ACV), has rotors and a cushion, where inside air pressure enables floating and smooth movement on any surface [26][27][28][29][30][31], such as land, mud, water, sand, and even on ice. The hovercraft is very active and agile; hence, it is applied widely in the coastguard, army, rescue operations, civil engineering, etc.…”

“…where τ is the torque in yaw rotation and F is the force acting along surge direction. The hovercraft dynamic models were derived in [28][29][30][31] using right-hand convention coordinate systems. The positive x-axis covers the lateral factors, namely, sway motion or surge position, while the y-axis is the direction along the hovercraft body, covering surge motion or sway position; and the positive z-axis defines the downwards direction.…”

“…A hovercraft, also known as an air cushion vehicle (ACV), moves smoothly on any surface [26][27][28][29][30][31] from the ground-land to the mud, water, sand, and even on ice. Because a hovercraft is very active and agile, its models was chosen for the control implementation.…”

Chaotic behaviors of an underactuated system in the trajectory tracking task

“…Complex chaotic behaviors were also observed in planar five-bar closed-chain mechanism [8]. In previous research, various types of underactuated hovercrafts were analyzed in terms of nonlinear control for trajectory tracking [1][2][3] but without input coupling effect and bifurcation analysis. This research focuses on chaotic behaviors of an underactuated system controlled with novel full-state control method with pseudoinverse operation, where irregular behaviors stand from the input's limitation, not from dynamics and control.…”