A school of fish in NordAquarium, Denmark

I recorded this video when we visited NordAquarium, Denmark.
This is a good documentary for our interests of bio-inspired robotics.

Probabilistic Potential Field for Robot Formation

We have succeeded in developing a new method of potential field for robot formation, called Probabilistic Potential Field (PPF). The approach is targeted on distributed control of robot swarm because the potential field is individually established by each robot. There are 3 major novelties of this approach different from previously developed methods:
1) The attractive and repulsive forces have been developed based on communication only, not including perception.
2) The potential field is a probabilitic function, not pre-assumed based on diffirential equations .
3) The probabilistic function has been developed based on empirical measure of the robots' communication

We sucessfully demonstrated that, a swarm of mobile robots can form and maintain hexagonal and square lattice. Impressingly, we can achieve the formation transition from square to hexagonal lattices without predetermination. The alternative is only obtained if the diagonal robots are fixed with their position in the formation.

This result is documented in an scientific paper and we hope to publish it very soon!

A realtime performance of hexagonal formation:


Square formation maintainance:


and


The formation transition from square to hexagon:






Browser our youtube for more video clips
http://www.youtube.com/user/TheMoreThanOne

New experiment of swarming aggregation on real robots

We have done some experiments to test algorithms of swarm aggregation. Basically, we would like to see how our robots can maintain their connectivities when we use probablistic directional communication as the attractive forces. We also manupulated the environment to observe how robots can search their swarm and how the swarm can gather their lost members.

The results are quite opministic!

The first experiment presents how three small scatted groups will cluster into united swarm.


The second experiment confirmed the robustness of swarm aggregation


The third experiment presents how robots can search their swarm and how they swarm can gather their lost members. To do that, we manipulated the environment during the experiment

EU proposal in FP7-ARGI : ICT-WAT

The lab participated in an EU proprosal in FP7-AGRI named "ICT-WAT: Information and Communicaton Technologies in Sustainable Water Resources Management in Argiculture". The project proposal is about using wireless sensor network to optimize the usage of the water on the field.
The partners are:
1. Agricultural Universtiy of Athens (AUA), Greece: Coordinator
2. Agricultural Research Council Research Unit (CRA-SCA), Italy.
3. Aalborg University, Denmark
4. EPSILON Italia SRL, Italy.

The total budget is about 300.000 Euro in which AAU will take 120.000 Euro

Simulation platform (updated)

We developed a simulation platform for our robot swarm. The impressive characteristics of this platform consists of:
1. Robot: Physics-based model. Instead of using unicycle or point mass robot model, we developed a physics-based model that illustrates how the real robots act in the environment. Furthermore, we developed a sensor model for infrared beam to ensure that the robot can only communicate with other robots and detect objects if they are within their sensing and communication beam. This model is much more realistic to the robot design than many existing sensor models.
2. Control: Adaptive PID control. The control is developed to clarify how we control the real robots using adaptive PID control. This control can be selectively applied or not.
3. Swarming algorithms: 3 branches of swarm algorithms developed for simulation
a) Directional signal based swarm: The algorithm is based on directional signal. Using the algorithm, a robot will react to the first signal it perceives.
b) Signal intensity based swarm: The algorithm is based on signal intensity. Applying this algorithm, a robot will react to the signal intensity of its neighbours. There are two versions developed in the platform
c) Neural network based swarm: The algorithm is based on a signal processing of sensory inputs using a neural network. There are two versions developed in the platform

Here is the screenshot of this software platform.

A brief desciption of the functions of this platform:
- Number of robots can be added unlimitedly
- Five different algorithms are switched online
- The scenario can be pre-arranged with a set of user-defined obstacles
- The speed of robots can be online adjusted at all or on individual robots
- Functions of grouping and PID control can be online selected
- Kp, Ki, Kd of PID can be adjustable online
- Sensor beam of all robots or individual can be show on or off
- Noise to sensory reading is adjustable.
- Values of each sensor on the robots are visible
- Number of neighbouring robots are realtime checked and visibly shown.
- The sensor beam can be activated or disactivated online.
- The speed balance of diffirential motors are adjustable.
- Light source diameter is adjustable and blind pot between robots under light conditions are implemented
- Output of simulation in terms of robots' position and orientation are saved in plain text for post-process


The first video clip of our simulation platform (consisting of a only)


The second video clip of our simulation platform (consisting of a,b,c)

Swarm algorithms: Simulation and Real Implementation

One group of the lab has developed swarming behaviors based on neutral network. The algorithm is one of three algorithms they have developed their semester thesis: (1)directional signal based swarm, (2) signal intensity based swarm, and (3) neural network based swarm.
They developed algorithms on Simulation platform using Visual C++ and implemented the algorithms on our small-scale robots.

Here is one of video clip of Neural network based robot swarm

EU proposal in ICT-FP7: ACSwarm

The lab submitted mini-EU proposal named ACSwarm: Swarm of Afforable Robots for multi-model clearning. The project is conducted on the cooperation of AAU Dept. Electronics Systems, Automation and Control (principal investigator), AAU Dept. Mechanical Engineering (project coordinator), RoboMop International A/S (industrial partners and equipment provider).
The project is about using swarm of afforable robots for concurrently wet-dry cleaning.
A summary of this project proposal can be seen below:
"Mobile robotic systems nowadays have potential to take place of human workers in domestic or professional working environments for saving time and cost. However, the widespread use of mobile robots has not come yet. A major barrier is the low performance/price ratio (P2R), which implies a low profit or level of satisfaction against the high investment. Technology that is able to improve the P2R of robots is pressingly demanded.
This project is concerned with the swarm technology of affordable cleaning robots in floor cleanings. The objective is to enable a swarm of affordable cleaning robots to work collaboratively with multiple modes, including wet and dry mopping. The swarm will improve cleaning performance and increase the flexibility to deal with different situations, thus lead to increased P2R for cleaning robot products.
In this project, experiments will be conducted with a swarm of low-cost cleaning robots, namely, RoboMop (€25), with an aim to upgrade this affordable robot to be highly controllable and flexible for a variety of cleaning purposes. The robot will be modified and modelled for the swarm control. A new approach to regulate robots in swarm to work adaptively and flexibly will be experimentally studied. The swarm algorithm, sensing and communication method, the plug & play deployment of a swarm will be tested in the experiments. The results of the experiments are expected to further the state-of-the-art of swarm robotics, particularly, the application of swarm robotics in the physical functions in the real world."

The total budget is 310.000 Euro in which AAU Automation and Control will take 150.000 Euro

AAU and RoboMop cooperation

Cooperation between AAU (Department of Mechanical engineering (ME) and Department of Electronic Department (ES)) and RoboMop is launched. While ME will modify the non-controllable design to be controlable, our lab will focus on development of distributed algorithm of deformable formation and trilateration based planning and replanning. Our sensor board will be used for the research. Initiative of this cooperation is resulted in a EU project proposal that will be submitted to ECHORD.

Updated on April 24 2010!!!
Here are pictures of the modified RoboMop prototyping equipped with our sensor board.



Here is CAD model of the current Robomop

The sensor board is mounted on the steering platform

The CAD model of new robot prototype

New small-scaled robot platform developed in the lab

We developed a new small-scaled robot platforms for our real experiments in swarm formation. The new platform has very high speed that are required to demonstrate the distributed algorithm of robot formation.
The control architecture of this platform is very powerful, including 2 IR sensor and communication boards and 1 RF and Bluetooth wireless communication. Inter-connection between the boards is conducted via I2C.
More information of our test and picture of this platform will be posted latter

Updated on 26 April 2010
Here is our mock-up of this robot platform.



and our "assembly" expert.

EU proposal in FP7-ICT: SENSAFE

The lab submitted a mini-EU proposal named SENse based SAFEty in Human-Robot Interaction to EU-ECHORD.
The project is about how to prevent the robot's attack and protect the human worker when working together the mobile robots.
Summary of this proposal can be seen as follows:
"A challenge of applying robots to our daily life is safety: how to ensure that robots will in cooperation reliably assist human, not harm them instead. This subject has intensively received the attention from the dawn of robotics industry: “a robot may not injure a human being or, through inaction, allow a human being to come to harm”- Issac Asimov – 1942. Because of imperative impact of robots to human safety, there exist standard for robot development and human safety issued by either standard organizations, i.e., American National Standard Institute (ANSI), U.S Occupational Safety and Heath Administration (OSHA), Canadian standard organization (CAN), International Standard Organization (OSI), etc or robot manufacturers, i.e., ABB, KUKA, Ries, etc. While all standards mainly concerns the safety aspects of industrial robots, the robotic industry has been rapidly grown with appearances of new generations of robots as professional service robots and personal service robots that assist human through direct or indirect interaction in the human-life workspace, establishing a new robotic subject, human-robot interaction/cooperation. This requires that the standards could be revised and improved to meet the on-going development of new robots as stated in the second part of evolving ISO10218.
In SENSAFE we suppose that human and service robots share the workspace, and implicitly or explicitly cooperate to finish assigned tasks. Risks of human in the workspace essentially come from the attack of robots caused by its functioning failures. The reasoning of robot’s failures can be either control system unreliability or misunderstanding human’s commands. However, based on the general close-loop-model of robotic systems, “sense-think-act”, “sense” is the first component that plays a role as perceptual, representational, or reasoning input to the sequence “think-act”, hence it essentially becomes the reason causing the malfunction of the robots due to uncertain conditions of the working environment and unpredictable actions of human co-workers.
The SENSAFE project aims to research and develop a new experiment-based knowledge (empirical knowledge) on how to determine modes of operation and control of robots according to safeguarding and clearance between the robots and human in the human-life workspace based on the robot’s “sense”. The objective of SENSAFE is to develop experiments for assessing safety levels of human co-working in the shared workspace. The research of this project is to contribute to: 1) society in terms of deeper understanding of human risks in the manner of human protection and injury minimisation when sharing workspace with service robots; 2) industry in terms of technological standards for development of service robots working in human shared workspace; 3) science in terms of techniques and algorithms for safe human-robot interaction/cooperation"