Tomislav Haus

Combined actuator sensor unit for interaction with honeybees

Interacting with a specific animal society by integrating autonomous robot/s into the society, has become a powerful method to influence the behaviour of animals and investigate collective behaviour of both, animal and robot societies. In order to interact with animals, artificial unit/s should be well integrated into their society. In the European project ASSISIbf, a network of static autonomous robots called CASUs (Combined Actuator Sensor Units) for interaction with young honeybees has been designed. In the proposed approach CASUs can affect honeybees using three types of physical stimuli: heat, vibration and light. To provide feedback signals necessary for controlling CASU interaction with honeybees, accurate and reliable measurements of the stimuli are necessary. This paper describes the mechanical and electronic design of CASUs, capable of emitting controllable heat, vibration and light stimulations. Each CASU is equipped with temperature sensors, 3-axis accelerometers, infrared proximity sensors and microcontroller for data processing. Preliminary experimental results with honeybee groups are presented.

State estimation, robust control and obstacle avoidance for multicopter in cluttered environments: EuRoC experience and results

This paper reports the results of the UNIZG-FER team in the third European Robotics Challenge (EuRoC). More precisely, the results of the 1st qualifying stage of the challenge where a micro aerial vehicle (MAV) is tested in realistic simulation scenarios. The paper presents the entire controller setup, starting from the power distribution level, low level cascade controllers with wind disturbance rejection to high level obstacle avoidance algorithms. The proposed controllers were tested in realistic simulations environments where their effectiveness was evaluated based on objective criteria set by the challenge organizers.

Spincopter Wing Design and Flight Control

This paper presents dynamical properties of an unmanned aerial vehicle (UAV), called spincopter. The vehicle structure is based on two wings that are forced in rotation (spinning) by propulsion system formed of two propellers. Based on devised dynamical model, that reveals inherent stability of the vehicle, composition of control algorithms for vertical and horizontal movement is proposed. Due to the specific configuration of the propulsion system, movement in horizontal direction is produced by pulsations in rotational speed of propulsion motors. An analysis of influence that such a configuration has on the vehicle dynamics is given. Finally, design recommendations for rotational wings are elaborated, based on extensive simulations of spincopter by using X-Plane® software package.

A novel concept of attitude control for large multirotor-UAVs based on moving mass control

In this work we aim to explore the concept of using the shift in the center of gravity, which in turn produces roll and pitch moments, to control the attitude of the quadrotor. We propose constructing a UAV with moving masses within each rotor arm. In this paper we show the mathematical equations describing the dynamics of the proposed system, propose a classical PID based control approach and analyze and confirm its stability. Furthermore, we analyze the effectiveness of the proposed controller in a Gazebo based simulation environment. Finally, we build a laboratory testbed that emulates the dynamics of the system and test our proposed control strategy.

Social Adaptation of Robots for Modulating Self-Organization in Animal Societies

The goal of the work presented here is to influence the overall behaviour of specific animal societies by integrating computational mechatronic devices (robots) into those societies. To do so, these devices should be accepted by the animals aspart of the society and/or as part of the collectively formed environment. For that, we have developed two sets of robotic hardware for integrating into societies of two different animals: zebra fish and young honeybees. We also developed mechanisms to provide feedback from the behaviours of societies for the controllers of the robotic system. Two different computational methods are then used as the controllers of the robots in simulation and successfully adapted by evolutionary algorithms to influence the simulated animals for desired behaviours. Together, these advances in mechatronic hardware, feedback mechanisms, and controller methodology are laying essential foundations to facilitate experiments on modulating self-organised behaviour in mixed animal -- robot societies.

Visual Target Localization with the Spincopter

The goal of the Spincopter project was to design an energy efficient aircraft capable of autorotation glide that could be used for both indoor and outdoor surveillance. This paper demonstrates how to utilize the self-rotating capability of the Spincopter in order to acquire a 3D image of its environment and localize predefined object(s). The omnidirectional capabilities of such an UAV extends the otherwise very limited field of view of conventional cameras usually used for aerial photography and surveillance. The paper presents the theoretical background and the actual implementation of such a system. It presents the resulting images and offers a brief survey of the image quality.

Modeling, simulation and control of a spincopter

In this article we present a mathematical model of a spincopter - an inherently stable and easy to control unmanned aerial vehicle (UAV). Although the devised model represents only the first approximation of spincopters physics, it captures basic phenomena that are sufficient for derivation and testing of a simple control algorithm. Results obtained by simulations in Simulink®, presented herein, demonstrate efficient performance of the proposed simple controller structure. Further tests, including investigation of complex aerodynamics effects and hardware-specified limitations, have been done using X-Plane® software package. Finally, the proposed controller has been tested experimentally. Both, X-Plane® and experimental results confirmed the outcome from Simulink®.

Aerial-ground robotic system for autonomous delivery tasks

In this paper we present a study of a robotic system that consists of an unmanned aerial vehicle equipped with a pair of manipulator arms (MMUAV), and unmanned ground vehicles (UGVs). The envisioned application scenario includes autonomous packet transportation, where MMUAV is used for picking/placing packets, while both MMUAV and UGV can be used for packet transportation, with different energy consumption profiles. We propose a reactive method for decentralized task planning and coordination of robots using hierarchical task decomposition based on TÆMS framework. Our approach takes into account low-level motion-planning aspects of the system as well as high-level mission specification, making this a multi-layered system. For low-level planning we use sampling-based planner combined with obstacle-free trajectory generation. Methods are verified in simulations and on an experimental testbed, using 3D Robotics quadcopter and Pioneer 3DX mobile robots with the results showing stability and robustness of the presented methods.

ASSISI: Charged Hot Bees Shakin' in the Spotlight

In this article we describe the concept of generating a mixed society of honeybees and artificial (robotic) agents in the project ASSISI|bf. We discuss the motivation of generating a mixed society as novel bio-hybrid system that can achieve self-awareness, self-regulation and environmental awareness through self-organization and collective information processing. In our approach the artificial agents communicate with the natural agents through 4 physical channels, which are emphasized in this article: temperature, vibration, electromagnetic fields, and light. We also discuss our methodology of automated model-generation and model-adaptation through evolutionary robotics principles.

Design considerations for a large quadrotor with moving mass control

In this paper we present our ongoing efforts to build a heavy lift multirotor platform capable of lifting over 50kg of payload. Such a system requires a paradigm shift in the design of the UAV. Therefore we propose using miniature two stroke internal combustion engines to supply the necessary lift and endurance and combine them with a novel control concept based on the variations of the center of gravity (CoG) of the system. In this paper we present a detailed stability and sensitivity analysis of the proposed control scheme and discuss its underlining effect on the construction design parametrization. We present simulation results from a Gazebo based simulator that confirm the results of our mathematical analysis.