Saturday, October 25, 2008
The stream can be found here:
(or if you are behind a draconian firewall rtsp://126.96.36.199:80/Live1.sdp)
(or if you are behind a draconian firewall rtsp://188.8.131.52:80/Live2.sdp)
One will follow the robots, one will cover the controlling team
At 9 pm the challenge started with the team from Finland, who where followed by the Jacobs University Bremen and Madrid. The team from the UK was unfortunately unable to start due to three
The base camp at night. It’s a really magical place at night. It’s buzzing with students that work in the dark outside their trucks, giving the last finish to their equipment before getting to start.
This is how the way to the actual crater looks like.
The team of the Jacobs University Bremen are about to start. While the Lander is illuminated with this very weak side light, the inside of the crater is completely dark.
The two robots right at the edge where we were testing today. The slope is not as steep as it appears in this picture, but even for humans, it’s really hard to get up the sandy inclines.
Our team on the top of our testing peak. It’s Tenerife, but we’re at more than 2000 meter altitude. So it’s not too warm. From left to right: Andi Lauber, Cédric Pradalier, Martin Latta, Oliver Baur, and David Remy.
Thursday, October 23, 2008
Martin, Andy, and Oli finished the sealing work on the walking robot in the morning, and adapted our gaits and calibration to the new configuration (with scales and ground plates). Unfortunately, once they were ready to test, it started to rain at the camp. So we have to do our big all systems test tomorrow. On the other side, they were able to take advantage of the time, and implemented additional motions for the walking robot. We’re now able to crawl way faster. Traveling about two meters/minute (which should now be fast enough to complete the mission in the given time span of two hours). We also implemented some motions for fine adjustment and collection of the soil samples. Tomorrow, ESA will provide the actual sample material, so we’ll know how this will work out.
Andy and Martin spend the entire day working on the walking robot. For the first time, we put on the pajamas (which miraculously fit) and made everything sand proof. Also the metal ‘scales’ on the shanks and the main body were mounted. We are really happy to see that the range of motion was not reduced by these additions. In the late afternoon, we were able to make some first crawling trials and saw that the robot behaves very nicely in sand. The motions are smoother then on the hard floors of our ETH-lab, and it seems that the robot has the climbing abilities that we hoped for.
Cedric ran some tests with the Crabli, which was being operated in an outside environment for the first time, as well. It worked as we hoped, no mayor problems with the steering and communication. The only issue we have to deal with are little rocks, that can get stuck in the wheels of the rover and block them. So I guess, there will be some tape, paper, and maybe tooth brushes to form some simple protection during the actual challenge. I was working on the SpaghettiBOT (as we started calling our winch), but (besides tons of Blue-Screens) nothing really special happened there.
Also the starting order was determined today. We will start as team 7 of 8. On the upside that means that we have one more day of testing then the others and can learn from them. On the downside we have to start around 1am (local time) Sunday morning when it will be really, really cold! If you want to watch this event, ESA will provide two live video streams during the actual challenge. They will be visible with Quicktime or VLC and can be found at the URLs:
(or if you are behind a draconian firewall rtsp://184.108.40.206:80/Live1.sdp)
(or if you are behind a draconian firewall rtsp://220.127.116.11:80/Live2.sdp)
One will follow the robots, one will cover the controlling team (freezing in the night). Our turn is Sunday morning at 2am (Zurich time), so this might be a nice thing to watch after coming home from going out.
Our first day started rather slowly. ESA was putting up the challenge site on which we took a short stroll before we explored the area around el Teide. It was really nice to be at the actually testing grounds and to see what our robot has to handle. During the last months, the only information we got about the challenge came from the blogs of our competitors and google-earth. It gave us a rather abstract and competitive feeling about this event. But seeing the crater today, we realized that the challenge is not at all about being better then the other teams, but about completing the mission scenario. But even if we fail to do so, the entire project will be a great success. Just getting a robot here and being able to test it in an environment that no lab in the world can provide, is more then we could have asked for. The crater seems bigger in reality then we imagined it. It’s also way steeper then we thought and the bottom is covered with big rocks. The soil is made up of granular volcanic rocks (with a couple of millimeters in diameter) that are super-light and, despite their size, almost behave like sand. So we’re really happy to have a tethered solution that will help us get the robot uphill.
Our urges to start immediately were hold back by a lack of robots, which arrived at around 4 pm at the testing site. Thank god, nothing was damaged during shipping. Once they were there, we instantly set up shop in our truck before we had to go to the security debriefing at our hotel.
Wednesday, October 8, 2008
This was the first complete system test, less than 20 hours before the departure of the robots. In this test we had:
- The ASL Walking robot (complete with cover and lights)
- The ASL Crabli (6 wheeled rover)
- The ASL SpaghettiBot (Power cable manager)
The video is a recording of what was visible via the Crabli's camera, sped up 5 times. This camera was also used to drive the crabli, not to record the experiment. As a results, the image has saccades and sometimes focus on weird things such as the Crabli's own wheels.
Even if we would have used the opportunity of more testing, we are quite happy that our infrastructure is now working properly. Our control stations are stable and usable, our wireless network can handle the load, our night perception is acceptable and our locomotion capabilities have been proven.
How will we do in the sand outdoor? Let's wait and see...
In contrast to our initial plan of having a drill-like collector, we decided to go for a simpler shovel mechanism that is just lowered into the ground and filled by slowly sliding the robot forward. It looks a little bit like a bird’s beak.
Mechanical benefits are the increased stiffness with some reduction in weight, and additional sensors to measure all joint angles. Additionally the robot is now fully protected against environmental influences. However, we’re not planning of putting it in the rain until the competition is over.
The upcoming week is fully designated to testing. The main focus will thereby be on the cooperation of the individual systems. That means, looking at the communication, power consumption, and maneuverability in the dark. Another goal is to get some long term operation experience before we have to pack our boxes and ship them to Tenerife. We want to figure out witch components are working well, and which are prone to error while we’re still able to patch. Other issues that we couldn’t yet examine are friction, wear, and especially heat accumulation and its influence on the different components.
The fine-tuning and finalization of the locomotion concept will be done on the spot in Tenerife were we can test in the actual conditions and environment of the competition.
Saturday, October 4, 2008
Everything was on an extremely tight schedule for the preparation of the Night of Science. After pulling some long, long evenings, we finished the new prototype literally in the very last minute. Some of the final assemblies were actually done in the exhibition tent. The great effort of the students was rewarded by an extremely open and interested crowd that was drawn in large numbers to our booth.
The only drawback was a small error in the NI-software. It sometimes caused misinterpretations of the sensor signals and made demonstrations impossible. Still, we got good feedback and the new prototype was a real highlight in the exhibition; especially for the younger visitors.
Thursday, October 2, 2008
Wednesday, October 1, 2008
For this robot the LRC will be the first field mission, and we’re really curious about its locomotion abilities in such a harsh environment.
Monday, September 1, 2008
In a breadboard environment we evaluated the idea of directly reading the sensor information via the cRIO system. This would eliminate the need for additional servo boards at each leg and frees the CAN-Bus from some of its load. We also would have additional 16 analog channels available, which can for example be used to monitor the motor temperatures. Digital filters were implemented in the FPGA and the control code was ported to NI LabView were it runs in real-time at with a higher frequency.
So far the move seems to be a great success. And with the new singleboardRIO, it will become feasible to have the computation on board without adding a lot of additional weight.
The workshop has finished manufacturing of the new robot frame. Currently the composite casing is being built. Together they will provide a very stiff framework for the mechanical components and will also provide a dust-prove housing for the electronic components. With this step the mechanical redesign for the robot is finished and we can move on to integrate the specimen collecting mechanism. We also created a prototype for the textile cover of the legs. This was one of the critical issues, as we suspected that part of the fabric might jam the joint motion. However, preliminary test seemed promising.
Friday, July 18, 2008
Monday, July 14, 2008
Our basic concept is a team-based implementation of two tethered devices: a wheeled rover providing overview sight, power supply and a communication bridge and a legged climber that will fullfill the main tasks as descend into the crater, sample some soil specimen, climb up the slope and return the samples to the landing site.
A fully covered second prototype of the legged robot ALF will be constructed and manufactured soon. The higher torsional stiffness allows more accurate control for reliable walking abilities and the cover protects the interior against sand and dust.
As a sampling mechanism, we are suggesting a drilling device (Archimedes screw) to draw the granular specimen. It will be located at the front and the suction procedure will happen in an animal-like way.
Sunday, July 6, 2008
The design of the legs proved to be well done. They are robust, flexible, and still lightweight and compact. We will have to make some small adaptations to the sensor placement and the integration of the elasticities. The only thing that will be completely new are the feet. They will be specially designed for a sandy environment and equipped with some climbing aids. But apart from that the overall leg design will remain the same.
In contrast to that, the main body will undergo a complete redesign. We need to increase the torsional stiffness, make room for the specimen collector (which also has to be developed), and increase the robustness such that the robot will survive a fall or tipping over. Last but not least, we have to cover everything and protect the interior from sand.
Adapting electronics will mean mostly adding components: Camera systems, wireless communication, additional sensors, on-board control, and power supply. We will use the same actuators as in the existing prototype as they turned out to have a great balance of size, weight, and power. We will add simple footswitches to detect ground contact while the robot is upright (we first wanted to actually measure the forces, but considering that the robot will undergo various leg configurations, this seems just impossible), there will be inertial measurement, and some supervising sensors. And most importantly, we will focus on a tight integration of electronic components into the mechanical hardware.
The development of the controls is naturally one of the most important parts in such a project. Right now we’re working with predefined trajectories. I.e., a set of open loop joint angles that lead to walking, turning, etc. This collection will be extended to include tasks like standing up, or turning back into an upright position, crawling, crabbing, and the like. The long term goal is, of course, the generation of the motor inputs on line, to allow flexible navigation and at some point fast and dynamic locomotion.
Friday, July 4, 2008
Our LRC platform is based on the undergrad design project of Andi, Martin, and Atilla Yilmaz. During the last semester, they were developing a quadrupedal robot with series elastic actuation on the main joints of the legs. The goal was to develop a walking machine that is able to passively adapt to irregular terrain while walking statically, and can additionally use its elasticities to store energy during dynamic locomotion. Without knowing of the Lunar Robotics Challenge, they had named the robot ALF, already foreseeing that its future will not be limited to earth.
The project was a great success and we are certain, that a similar robot will perform well in the Lunar Robotics challenge. However, it is evident that we’re not even half way there yet. Major adaptations, improvements, and extensions have to be made to the original design, to get ALF space ready. This task will occupy us over the next couple of months.
Wednesday, July 2, 2008
My name is Fabian Seitz and my part is the implementation of communication tasks and assisting Oliver in software programming. This means to develop a framework in order to initialize and control the robot comfortable.
I'm studying mechanical engineering at ETH and focusing in my graduate program on robotics and autonomous systems.
The main issues on my part will be to generat stable walking gaits (which can also mean crawling or other locomotion modes) an control them during the critical step phases, preventing the robot to tilt over.
I'm an undergrad student in mechanical engineering with focus on robotics and mechatronics at the ETH Zurich. The main task I'm dealing with is to design an rigid body for the robot to ensure stable walking abilities.
Monday, June 30, 2008
I'm David Remy. My tasks in the Lunar Robotics Challenge are the coordination of the different work packages and giving support to our undergrad team members. I’ll also be helping with the control issues and I am the official team representative. Since February 2007 I'm doing my PhD at the Autonomous Systems Lab here at ETH Zurich. My research topic is legged locomotion, with a specially focus on the potential of exploiting the periodic nature of legged locomotion to save energy.
Tuesday, June 24, 2008
The conditions in such a crater make such an exploration very different from common planetary explorations. The crater edge is extremely steep (about 40 deg) and will be covered by rocks, boulders, and terraces. Landslides can occur every time the sand on the crater's slope is touched. Everything that makes the crater interesting for science (no sunlight, cold temperature, depth) makes it hard to explore.
To cope with this challenge, we proposed a robotic platform with four legs that can walk upright on normal surface, but switches to an arachnoid crawling gait when the terrain becomes rough.
In this Blog, we will keep you updated about the developing process, the steps we're taking, and the setbacks we suffer until we compete with our quadruped against seven other teams in late October.