The age-old human dream of versatile robots replacing people in dangerous places or doing tiresome work for them is beginning to come true in Poland. Researchers from the Silesian University of Technology in Gliwice have built the country's first mobile robot. For the time being, it is being sold mainly as a teaching aid, but soon it may also be used for guarding homes and companies, surveying land and helping rescue teams, for example, in coal mines.

The robot, called Hexor, has six metal legs and a trunk with a camera. It looks a bit like a scorpion. It can "see" thanks to its camera, and avoids obstacles owing to its three kinds of sensors-ultrasound, infrared and two tactile sensors in the front. With these sensors, the robot has excellent space orientation: it stops and turns back whenever it approaches a wall, walks around a human being in its way, and always finds an open door. The robot's camera sends images and makes it possible for people to remotely monitor rooms and buildings with the use of a computer or a mobile phone.

"Let us imagine we are at work worrying that we might have left the iron on at home," says Tomasz Stenzel, one of Hexor's designers. "It's enough to tell the robot to go to a specific place and send us an image from there. In the same way, we can monitor what our children are doing or supervise work being done in a distant office. Households are where mobile robots will be used on a mass scale in the future; they will take over typical household chores from people. For example, there are already vacuum-cleaner robots, though their use is still rather limited. An advanced mobile robot will be a kind of a modern majordomo. It will combine the features of a personal computer, a telephone, an answering machine and a television set. We will even be able to exchange a few words with it. Our robot is already prepared to generate voice signals. We have also tested a special application for voice control over a mobile phone."

Hexor the teacher
For the time being, the robot is mainly being used as a teaching aid. This was in fact the main aim of the project. In the current education system in Poland, many subjects that used to be taught separately, such as technology, electronics and information science, have now been merged into a single discipline called mechatronics. So any mechatronic equipment, which means something that includes mechanical elements controlled by an electronic circuit with a processor and appropriate software, can be a teaching aid. However, the devices widely available today, such as cellular phones, printers, and digital photo or video cameras, are self-contained products that cannot be modified in terms of either their structure or functioning. Meanwhile, future engineers and designers should study on the basis of "open-ended products" whose operation can be both observed and influenced.
Hexor addresses this need. It is the only "open-ended" mechatronic device available for teaching in Poland today. Students can not only learn how the robot functions, but they can also teach it certain behaviors. Advanced users may program its individual reactions to external stimuli, for example, color or temperature, with the use of the robot's sensors or by adding self-designed modules to it.

"Versatility is the main advantage of Hexor, though few teachers realize the great potential offered by such robots," Stenzel says. "The robot makes it possible to teach both mechanics and electronics. Its modular structure allows the user to modernize and expand it. This may also bring benefits for us: we hope that users will provide us with feedback and their own ideas for concrete commercial applications of these robots in the future."

Robots at work
The Hexor II robot, developed at the university in Gliwice, combines the features of the two previous models, Skorpion and Hexor I. This is in line with the designers' philosophy of taking advantage of users' experience and modernizing the product, in order to build a new, improved range of robots.

During numerous presentations, the designers are asked if Hexor can work outdoors, penetrate sites that are difficult to access for people such as furnaces, or clean the facades of high-rise buildings. Potential clients also want to know whether Hexor can walk the stairs, negotiate uneven surfaces, or jump.

"Building a technologically advanced robot does not depend merely on our skills, because the Electrical Department has great invention potential," says Stenzel. "This is an issue of money. When you operate on a market, you have to pay attention to the costs involved, especially since we want Hexor to be affordable to the general public. That is why, for the time being, the robot can only move around flat surfaces: we have decided to optimize its walking mechanism not to inflate the costs."

Hexor can walk...
The robot has six legs powered by three servo motors. The front and hind legs move only horizontally, while the middle pair of legs move vertically. The robot's stability and balance are ensured by at least three points of support.

... and see...
The robot can "see" with its Charged Couple Device camera installed at the top of its metal tail. Its high position allows for a wide viewing range. The camera lens can move both horizontally and vertically. The head is powered by two servo motors on top of the tail.

... and feel
Hexor can detect obstacles in its way owing to three types of sensors: a sonar, an infrared sensor module and tactile sensors. The sonar uses ultrasound waves that the human ear cannot hear to detect objects and measure distance. It emits acoustic waves and then measures the time it takes for the sound wave to return after it is reflected by the obstacle. This enables the robot to determine the distance. The sonar head is mounted at the top of the tail, close to the camera lens. This makes it possible to precisely measure the distance to an object detected by the robot. This feature is used in artificial intelligence applications for image recognition.

The infrared sensor module has four pairs of sensors that detect obstacles thanks to a reflected beam of infrared radiation emitted by the transmitter. The module is installed in the rear part of the robot.

Tactile sensors, known as the Bumper Switch (BS), installed on both sides of the body enable the robot to detect obstacles that are not registered by its other sensors.
Thanks to these three different "senses," the robot can move around and avoid collisions with obstacles in its way.

Obeying his master
The robot is controlled using an interactive method. The user sends a command via a control program installed on a personal computer connected to a Radio Base Module (RBM). The control program's screen displays the image from the robot's camera. The command sent via the control program is transmitted through a USB port to the RBM, and then by the radio to the robot.

Hexor interprets the command and, depending on its character, performs appropriate operations, for example, changing the direction of its movement or stopping. After receiving the command, the robot sends to the computer feedback with data about the surroundings registered by the sensors, for example, the distance to the closest obstacle on its way. Hexor can interpret signals from the sensors, so, in order to avoid bumping into an object, it stops immediately after detecting it. It informs the user about the operation and waits for further commands. But the robot can also work autonomously, following its own route. What's more, the user can modify and expand the procedures, changing the software of the robot's microcontroller or the personal computer software.

Artificial intelligence?
"The robot's behavior is spectacular," says Maciej Sajkowski, a software engineer who has developed the computer program for Hexor. "It approaches an object, stops, looks around using the sonar, checks where there is the most space and moves in that direction. Such behavior may to an extent be seen as an element of artificial intelligence, although Hexor is a finite state machine (FSM) and has a limited number of procedures. But if the computer controlling the robot were equipped with appropriate software, the project could develop in an interesting way," says Sajkowski.

The technology used in the Hexor project is on a par with international research into artificial intelligence. That is proved by the fact that one of the robots developed in Gliwice is being used in the United States in the Intelligent Robotics Laboratory at Portland State University in Portland, Oregon, which specializes in this kind of research. The robot is equipped with a special application because the laboratory focuses on software designed to imitate certain features of artificial intelligence. This particularly applies to phototropism, or reaction to light, color identification and behaviors typical of some insects, for example, moths. The laboratory also studies robots in terms of their ability to identify images, generate voice signals and produce other forms of "intelligent" behavior.

Hexor found its way to Portland owing to Prof. Marek Perkowski, who has been a professor at Portland State University since 1994. He is also the director of the university's Intelligent Robotics laboratory. A graduate of the Warsaw University of Technology, Perkowski concurrently works at the Industrial Robotics and Quantum Information laboratories in the United States. A large part of his research is devoted to quantum computers. He brought Hexor to Portland in 2003.

"In a sense, the robot developed by the Stenzel company is the best product we have seen so far," says Perkowski. "It has a good mechanism, many sensors and integrated software. It also has integrated radio controls and can be controlled with the software of a standard personal computer. Besides, the robot has an appealing look. Many people like it because of its esthetic, imaginative and solid structure."

Hexor is not the only mechatronic teaching aid available on the Polish market. Some Western companies also offer such equipment, but it comes with specific software that cannot be used in any other devices. This means that students cannot use their knowledge in their professional work later on. In this respect, Hexor has no competition.

The Electrical Department of the Silesian University of Technology has created a mobile-robot laboratory in order to provide better educational opportunities for students. Equipped with eight Hexor II robots with complete hardware and software, the unit is the most technologically advanced laboratory in southern Poland. Its aim is to provide top-grade education and promote robotics among high-school teachers.
Ewa Dereń


How Hexor Was Born
The mobile robot Hexor was created at the Electrical Department of the Silesian University of Technology in Gliwice. The design team includes the department's Tomasz Stenzel and Maciej Sajkowski, backed by the experience of Prof. Bogusław Grzesik and Prof. Kazimierz Gierlotka, and Mariusz Mroczek, a private IT entrepreneur from MAK Sp. z o.o. The robot's production was launched owing to the financial assistance of the sponsor, Górnośląski Zakład Elektroenergetyczny power company, which, together with its investor, the Vattenfall corporation, supports the development of education and entrepreneurship in Upper Silesia. These companies also finance the mobile-robot laboratory. The Hexor robot is produced by Spółka Technologiczna Stenzel Sp. z o.o. that forms part of the Electrical Department.