Gyula Mester

Wireless sensor-based control of mobile robots motion

The paper deals with the wireless sensor-based remote control of mobile robots motion in an unknown environment with obstacles using the Bluetooth wireless transmission and Sun SPOT technology. The Sun SPOT is designed to be a flexible development platform, capable of hosting widely differing application modules. Web technologies are changing the education in robotics. A feature of remote control laboratories is that users can interact with real mobile robot motion processes through the Internet. Motion control of mobile robots is very important research field today, because mobile robots are a interesting subject both in scientific research and practical applications. In this paper the object of the remote control is the Boe-Bot mobile robot from Parallax. This Boe-Bot mobile robot is the simplest, low-cost platform and the most suitable for the small-sized, light, battery-driven autonomous vehicle. The vehicle has two driving wheels and the angular velocities of the two wheels are independently controlled. When the vehicle is moving towards the target in an unknown environment with obstacles, an avoiding strategy is necessary. A remote control program has been implemented.

Adaptive force and position control of rigid-link flexible-joint SCARA robots

In this paper a new form of direct adaptive force and position control of rigid-link flexible-joints 4 DOF SCARA robots has been presented. The control law of the adaptive scheme for position control consists of a PD regulator and adaptive model-based feedforward compensation of full dynamics, together with a simple linear correction term from motor velocity based on the estimated parameters to compensate the elastic oscillations at the joints. The algorithm is computationally simple, the adaptive controllers do not require knowledge of the parameter values of the robot or the environment. Results of the computer simulation applied to this robot show the validity of the proposed method.<<ETX>>

Modeling and simulation of quad-rotor dynamics and spatial navigation

The paper regards modeling, control and simulation of a quad-rotor rotorcraft machine that represents an advanced aerial robot. The main contribution of this paper focuses to the development of a flight simulator to provide advanced R/D tool suitable for control design and model evaluation of a quad-rotor systems to be used for control algorithms development and verification before working with real experimental system. The main aspects of modeling of rotorcraft kinematics and rigid body dynamics, spatial system localization and navigation are considered in the paper. Some high-level control aspects are considered, too. Several basic maneuvers (examples) are investigated and simulated in the paper to verify the simulation software capabilities and engineering capabilities.

Obstacle Avoidance of Mobile Robots in Unknown Environments

This paper gives the fuzzy control of a wheeled mobile robot motion in an unknown environment with obstacles. The model of the vehicle has two driving wheels and the angular velocities of the two wheels are independently controlled. When the vehicle is moving towards the target and the sensors detect an obstacle, an avoiding strategy is necessary. We proposed a fuzzy reactive navigation strategy of collision-free motion in an unknown environment with obstacles. First, the kinematic modeling of the autonomous wheeled mobile robots is analyzed. Then the fuzzy control of a wheeled mobile robot motion in an unknown environment with obstacles is proposed. Output of the fuzzy controller are the angular speed difference between the left and right wheels of the vehicle and the vehicle velocity. The simulation results show the effectiveness and the validity of the obstacle avoidance behavior in an unknown environment of the proposed fuzzy control strategy.

Intelligent Mobile Robot Controller Design

This paper gives the fuzzy reactive control of a wheeled mobile robot motion in an unknown environment with obstacles. The model of the vehicle has two driving wheels and the angular velocities of the two wheels are independently controlled. When the vehicle is moving towards the target and the sensors detect an obstacle, an avoiding strategy is necessary. We proposed a fuzzy reactive navigation strategy of collision-free motion in an unknown environment with obstacles. First, the vehicle kinematics constraints and kinematics model are analyzed. Then the fuzzy reactive control of a wheeled mobile robot motion in an unknown environment with obstacles is proposed. The simulation results show the effectiveness and the validity of the obstacle avoidance behavior in an unknown environment of the proposed fuzzy control strategy

Neuro-fuzzy-genetic controller design for robot manipulators

In this paper, a new form of neuro-fuzzy-genetic controller design for rigid-link flexible-joints robot manipulator applications has been presented. The control algorithm uses fuzzy logic with neural membership functions and a rule base without needing the knowledge of the mathematical model or the parameter values of the robot. The genetic algorithms are applied for fuzzy rules set optimization. The proposed controller is capable of compensating the elastic oscillations at the robot joints. The obtained membership functions and fuzzy rules are implemented with backpropagation feedforward neural networks. The membership functions are modified through a learning process as a fine tuning. Results of computer simulations, applied to four degree-of-freedom rigid-link flexible jointed SCARA robot manipulators, show the validity of the proposed method.

Obstacle avoidance and velocity control of mobile robots

This paper gives the fuzzy velocity control of a mobile robot motion in an unknown environment with obstacles. The model of the vehicle has two driving wheels and the angular velocities of the two wheels are independently controlled. When the vehicle is moving towards the target and the sensors detect an obstacle, an avoiding strategy and velocity control are necessary. We proposed a fuzzy reactive navigation strategy of collision-free motion and velocity control in an unknown environment with obstacles. Outputs of the fuzzy controller are the angular speed difference between the left and right wheels of the vehicle and the vehicle velocity. The simulation results show the effectiveness and the validity of the obstacle avoidance behavior in an unknown environment and velocity control of the proposed fuzzy control strategy.

Virtual WRSN — Modeling and simulation of wireless robot-sensor networked systems

The paper concerns with modeling and simulation of wireless robot and sensor networked systems. In that goal, a user-oriented Matlab/Simulink software toolbox called Virtual WRSN was designed with aim to support extensive research and development of such kind of non-linear integrated systems. Main applicative modules of the software simulator as well as background theory used for its development are presented in the paper. Some implementation aspects of the developed system are considered as well as some characteristic results are presented in the paper, too.

Ambient intelligent robot-sensor networks for environmental surveillance and remote sensing

The paper regards development of an ambient intelligent (aware), multi agent, robot-sensor networks for outdoor surveillance and monitoring of human living and working environments. Heterogeneous robot-sensor system consists of autonomous, ambient aware, robust outdoor mobile robots for performing environmental tasks and networked distributed terrestrial and water sensors integrated into the unique Shared Environmental Information System (SEIS). The goal is supervision, monitoring and remote sensing of territories and lands. More specifically, the objectives of the paper are addressed to design new methods and technology that integrate enhanced perception, based on heterogeneous sensor system, with advanced cognitive capabilities of mobile robots. Integrated solutions are planned to be validated in a real environment such as park of nature “Ada Ciganlija” (city of Belgrade), taking full advantage of dynamic ecological system and recent advances in ICT technology and sensor miniaturisation.

Flexible planetary gear drives in robotics

A method of modeling and computation of industrial robots with rigid-link flexible joints actuated by flexible planetary gear drives is presented. Joint flexibility, as a predominant source of resource, often results in inaccurate tracking of prescribed robot trajectories. The authors consider an n-link industrial robot modeled by rigid-body linkage members interconnected by flexible joints, actuated by DC servomotors and a flexible planetary gear system. The single-link joint model with one flexible planetary gear unit has six degrees of freedom (DOFs). In the gears the periodical time-dependent tooth stiffness represents an essential excitation source and was incorporated into a dynamic model of a robot system. The dynamic model of the robot with flexible joints for the case of elastic planetary gear is presented on example of the SCARA robots basic configuration for two DOFs.<<ETX>>