Aleksandar D. Rodic

Contribution to the integrated control synthesis of road vehicles

A nonlinear vehicle model with 22 motion degrees of freedom, used for synthesis of the system autopilot, was described in the paper. It was demonstrated how a controller can be designed on the basis of such relatively complex dynamic model, ensuring simultaneous motion stability of the vehicle in longitudinal, lateral and vertical directions, as well as the stability of roll, pitch, and yaw dynamics of the vehicle about corresponding axes. Vehicle automatic control was realized at two hierarchical levels: tactical and executional. Proposed scheme of the distributed hierarchy control enables control of entire vehicle dynamics as a multibody dynamic system. Control has been synthesized in such a way that the system satisfies set criteria of dynamic behavior. The synthesized controller improves system motion caused by action of casual, external perturbations, and internal inertial and centrifugal forces which appear as a consequence of an inadequately adapted ride velocity to the road geometry. Also, necessary information for estimation of unknown time-variant parameters of the dynamic model and of tire-road interaction were briefly given in the paper. Simulation results were presented and analyzed for one example of characteristic trajectory with perturbation of type of an uneven and slippery road, as well as a wind gust.

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.

Hybrid Dynamic Control Algorithm for Humanoid Robots Based on Reinforcement Learning

In this paper, hybrid integrated dynamic control algorithm for humanoid locomotion mechanism is presented. The proposed structure of controller involves two feedback loops: model-based dynamic controller including impart-force controller and reinforcement learning feedback controller around zero-moment point. The proposed new reinforcement learning algorithm is based on modified version of actor-critic architecture for dynamic reactive compensation. Simulation experiments were carried out in order to validate the proposed control approach.The obtained simulation results served as the basis for a critical evaluation of the controller performance.

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.

CONTRIBUTION TO THE INTEGRATED CONTROL OF BIPED LOCOMOTION MECHANISMS

This work is concerned with the integrated dynamic control of humanoid locomotion mechanisms based on the spatial dynamic model of the humanoid mechanism, a servo system model, and an environment model. The control scheme was synthesized using the centralized model of the system and the hierarchical principle, with tactical and executive control levels. The proposed structure of the dynamic controller involves four feedback loops: position-velocity feedback at the robotic mechanism joints, dynamic reaction feedback at Zero-Moment Point, impact force feedback at the instant when the foot strikes the ground, and the load feedback of the mechanism joints. Simulation experiments are carried out for a number of characteristic examples. The numerical results obtained, along with theoretical study, serve as the basis for a critical evaluation of the performance of the devised controller.

Contribution to the dynamic study of humanoid robots interacting with dynamic environment

The questions when and why one needs to use mathematical models, and especially the models of dynamics, represent still an unresolved issue. A general answer would be that dynamic modelling is needed as a tool when designing structure of the system and its control unit. In this case we talk about simulation. The other application is in on-line control of the system – the so-called dynamic control. While in simulation one generally uses the best available model, the control can be based on a reduced dynamics, depending on a particular task. The aim of this paper was to highlight the problems important for the dynamics of humanoids and their dynamic environment.

Autonomous Locomotion of Humanoid Robots in Presence of Mobile and Immobile Obstacles

The article is addressed to the control synthesis of an intelligent autonomous locomotion (artificial gait) of biped robots operating in unknown and unstructured dynamic environments, based on perception, spatial reasoning, and learning the skill of human locomotion. Focusing the research activities to the embodied cognition and computational intelligence, this paper contributes to the extension of the intelligent robot behavior through building advanced algorithms for dynamic environment understanding, simultaneous localization, trajectory prediction, path planning, obstacle avoidance, collision avoidance and scenario-driven behavior. The article includes some characteristic simulation results to demonstrate the efficiency of the developed control algorithms and verify the obtained results.

Scalable experimental platform for research, development and testing of networked robotic systems in informationally structured environments experimental testbed station for wireless robot-sensor networks

The paper regards building of a scalable experimental platform for research, development, testing and verification of navigation and control algorithms for Wireless Robot-Sensor Networked systems (WRSN). Concept of the corresponding experimental test-bed station, with appropriate hierarchy-distributed control structure, operated within informationally structured space (environment) is presented in the paper. Complementary software simulator (Virtual WRSN) to enable preliminary system analysis, control synthesis, tuning parameters and simulation is developed, too. Both, experimental and virtual testbed system provide complementary research and development tools for research and development of heterogeneous, scalable networked multi-agent robotic systems to be employed in industry, at home, in office, medical institutions, public buildings, etc., as service human-oriented robots in our everyday life.

Design of an integrated active control system for road vehicles operating with automated highway systems

A new concept of an integrated active control of road vehicles operating with automated highway systems (AHS) is established in the paper. In that sense, a hybrid neuro-dynamic vehicle controller was synthesised based on the centralised dynamic control and using a supplementary neuro-compensator. The approach of the two-levels (tactical and executive) distributed hierarchy control strategy was used in the synthesis of the vehicle controller. The use of the position control law or the combined position/force control law were proposed at the tactical control level. Adaptive control gains of the dynamic controller were determined at the tactical control level based on the examination of the system practical stability test in the six global motion directions. On the other hand, by introducing the supplementary neuro-compensator, greater robustness of the system automatic control of the vehicle was achieved. A suitable controller design based on a multiprocessor system is proposed in the paper.