There really is no such thing as scrap aluminum. A piece of just about any size is useful for building or fixing something around the lab. Here it's used to make a plate to attach a De-Sta-Co 205-S Hold Down Clamp to a t-slot.
Total cost was about $11 and now I don't have too worry about a drill bit getting stuck in something and being attacked with it as it spins around attached to the drill bit.
Una robot del delta de España. Hecho por efixoben. ¡Gran trabajo!
Hecho en México por Elías. Tengo gusto del diseño.
Más de México. "Ejemplo de integración de Robot Paralelo con línea de producción, se utiliza un sistema de visión artificial para el reconocimiento de botellas con posición y orientación aleatorias." ¡Trabajo agradable utiliza un sistema de visión artificial!
From the UK we have this monster delta robot made by Martin Price. Watch out because it has plans to replicate.
"A FANUC M-1iA 6-axis robot handles and deflashes plastic tape dispensers. Using iRVision 2D, the M-1iA robot locates and picks the parts. The FANUC M-1iA robot is designed for small part handling, high speed picking and assembly applications."
Progress has been made since we featured an earlier version of this robot last month, at this rate the ABB FlexPicker may have some competition to worry about. More info here.
Best Commercial Delta Robot
This video shows how a delta robot fits into the larger packaging system. Features like the powered belt chicane add excitement as the packaged bars approach the delta robot. Excellent voice over and sound effects add to the high quality video. Great work from Bosch Packaging Machines, USA.
Best DIY Delta Robot and Delta Robot of the Year
This robot doesn't care what you say about it's accuracy, it's an artist. Sketchy has that joie de vivre that separates the great delta robots from the good ones. It's work has been featured in prestigious exhibitions such as Dorkbot Bristol. It bares it's artistic soul for the world to see and download with open-source software and extensive documentation. Excellent work and congrats on winning the I Heart Robotics Delta Robot of the Year Award for 2010.
It comes well packed with all the parts in plastic bags covered in packing grease. Grab a rag and maybe some gloves before you open the box. Assembly is straightforward, though you may forget to put the stop ring and collar on before the headstock. The t-slots (square nuts 13mm wide by 5mm high) look like they are going to be very useful for setting up jigs. The machine is in metric except for the ruler to the right of the t-slots.
The configuration for the belt and pulleys seem reasonable, though you will need a screwdriver (included) to remove the cover.
The belt tensioning system looks like a good idea but time will tell.
It comes with a JT1 taper on the spindle, which means you shouldn't (ab)use the drill press as a mill. JT1 is a standard taper so replacement chucks are available.
The stop ring is a nice feature to prevent the chuck from being driven into the table if you were to accidentally drop the headstock.
The drill press comes with a digital read out which is a nice idea, but the display is nearly unreadable. It really needs a light. One of the annoying features is that it shipped with a nearly dead battery, just like the last calipers I bought which came with nearly dead battery and a backup nearly dead battery. I'm not sure which upsets me more, that vendors are cutting corners on batteries thinking nobody will notice or complain or that there is a factory somewhere making nearly dead batteries. This also means there is a market for nearly dead batteries, and there is probably competition to see who can make the cheapest batteries that function for the shortest period of time.
It comes with a screwdriver and hex keys, but I would have rather they spent the extra few cents on a real battery. Right now I am not enthusiastic about the handle shown above the screwdriver, in the future I expect to hate and or modify it.
It has a depth stop which appears to work well.
Here is the variable speed controls with a replaceable fuse and knob to control the speed.
I'm usually a fan of warning labels, but this is silly. Some dust? I want to know what dust to not known to the state of California the be harmful. There is no useful information being conveyed, except that you should be afraid of some but not all dust.
Overall, the drill press has a few nice features and the price is reasonable. The biggest problems are that the DRO is hard to read and the end of the handle isn't rounded. These problems are pretty easily fixed and considering the prices of some of the alternatives, this may be the only reasonable option despite the dead battery.
Before sending the part out to Shapeways for printing, a prototype was hand-made to check the dimensions and concept. Due to the small sizes and large loads the part needed to be made out of steel, so the prototype part was ground into shape from a large screw.
Design is an iterative process, that rarely produces optimal or even usable results on the first try. This series of posts will show some of that design process including the flaws of the initial prototypes and how they were resolved.
So this arm design looked like a good idea for a robot, if it had some more mobility.
So, how do you design a cable drive continuum robot appendage? Build a prototype.
How do you build a prototype? Build a cable drive prototyping system.
The initial design of the winch drum uses 1/16" steel cable with an stop attached to the end. So far things look good.
The first design flaw. The exit hole is normal to the surface of the drum which keeps the cable from lying flat. The next version places the hole much closer to tangent to the surface of the drum. If you are familiar with the three body problem then you will understand that ideally the exit hole should be shaped like a transfer orbit. A curved hole of the required shape can be made with a 3D printer, but it is difficult to manufacture with injection molding. Design for manufacturing.
Hope you're wearing your safety glasses, because that cable is about to unspool violently. Here you can also see another problem where the hole was placed in the center along the axis of the drum, which leaves little room for the cable to spool. The next design moves the hole closer to one side.
The smaller pulley is much smaller than the minimum bend radius of the cable.
String is more flexible than the steel cable, so testing can continue while new parts are being made.
Here is the drum and a idler pulley mounted with the cardboard cable drive prototyping system. The drum is designed to be attached to a servo in the actual robot.
The hole in the cardboard is made with a hole punch, and the idler pulley is attached to the cardboard with metal brad and a Protobrad™.
Here is a video of the system in action. Future versions will support two cables on the drum, with one being wound as the other is being unwound. This configuration will remove the need for the spring.
or "Why do we still need other sensors if the Kinect is so awesome?"
The Kinect is a great sensor and a game changer for mobile robotics, but it won't make every other sensor obsolete. Though maybe I can use it to convince someone to let me take apart a Swiss Ranger 4000.
Field of View
The field of view is an important consideration for sensors because if you can't see enough features you can't use scan matching/ICP to estimate your change in position. Imagine if you were in a giant white room with only one wall that was perfectly flat. if you walk along the wall there is no way to determine your movement except from how many steps you take. With a robot you have wheel slip and encoder errors that build up over time unless there are landmarks that can be used to bound the error.
The depth image on the Kinect has a field of view of 57.8°, whereas the Hokuyo lasers have between 240° and 270°, and the Neato XV-11's LIDAR has a full 360° view.
In addition to being able to view more features, the wider field of view also allows the robot to efficiently build a map without holes. A robot with a narrower field of view will constantly need to maneuver to fill in the missing pieces to build a complete map.
One solution would be to add more Kinects to increase the field of view. The main problem is the sheer volume of data. 640 x 480 x 30fps x (3 bytes of color + 2 bytes of Depth) puts us at close to the maximum speed of the USB bus, at least to the point where you are only going to get good performance with one Kinect per bus. My laptop has two USB buses that have accessible ports, and you might get four separate buses on a desktop. Assuming you down sample until it works computationally you still have to deal with power requirements, unless your robot is powered by a reactor, and possible interference from reflections to deal with.
Another simpler approach is to mount the Kinect on a servo to pan horizontally, this however reduces the robot to intermittent motion where it is constantly stopping and scanning. Depending on your robot's mechanical design you may be better off rotating the robot.
The minimum range for the Kinect is about 0.6m and the maximum range is somewhere between 4-5m depending on how much error your application can handle. The Hokuyo URG-04LX-UG01 works from 0.06m to 4m with 1% error, and the UTM-30LX works from 0.1m to 60m. The XV-11 LIDAR does 0.2m to 6m. So the Kinect will have the same problems as the more expensive laser range finders in terms of being able to see the end of a long hallway, but the bigger problem will be the Kinect's close range blind spot. I'm sure it wouldn't be hard to imagine the dangers of a soft squishy dynamic obstacle approaching a robot from behind, then standing within 0.6m (2ft) while the robot turns and drives forward over the now no longer dynamic obstacle. It can also make maneuvering in confined spaces difficult without a priori knowledge of the environment.
One solution to this would be to add an additional laser projector to the Kinect so that the baseline could be adjustable and the minimum range could be closer. Another approach would be to place the sensor on the robot looking downward at a point high enough to ensure that the dynamic obstacles and their parents were detectable at all times.
The maximum range will be limited by the need to be eye-safe, the power output of the Kinect laser is spread out as a set of points projected over a large surface area, while more traditional 2D laser scanners direct their entire power output to a single point. The 2D laser scanner will generally be capable of a longer range given accurate time-of-flight measurements. The other major limit to the Kinect's maximum range will be the need to make the Kinect wider to increase the distance between the laser projector and the IR imager to have a large enough baseline.
The environmental challenges for the outdoor use of laser scanners has been fairly well studied, with rain and dust being known problems. Changing lighting conditions, from clouds passing overhead, can also wreak havoc with some sensors. I would be interested in seeing experimental results using the Kinect outdoors, during the day, in adverse weather. However, it should work well at night with good weather.
One important question is, can the Kinect see snow?
Computation and Thermodynamics
(updated: 22:28 EST 12/17)
Having designed and built several mobile robots I can safely say that once all the software is debugged, all the electronics are rewired and actually labeled, and the mechanisms are all lubricated, the biggest problem is thermodynamics. Battery technologies are a set of trade-offs that in the end give you some amount of potential energy stored in a constant volume of space, having a constant mass.
The amount of operating time for the robot is limited by how fast you convert that potential energy into kinetic energy or heat. On the electromechanical side you can recover some energy by using regenerative breaking to convert kinetic energy into potential energy and heat. While researchers have made some progress on reversible computing, there is currently no regenerative computing so all of the energy spent computing ends up as heat. So as we add computation power to the robot we are effectively decreasing the operating time.
As the compute power is increased the run time is decreased, so to make up for it you can add more batteries. As you add more batteries the mass of the robot increases, so the motors need more power to accelerate the robot. So to make up for it you can add more batteries.
In terms of testing algorithms and getting research done, offloading computation to a ground station is a valid solution. However, it may not be a practical solution for regular operation since wireless networks may not have complete coverage or reliability.
As you may imagine these problems are worse if your robot is flying. On the upside, cooling the robot is easier.
With a little bit of work the Kinect can provide more than enough sensing capabilities to put your robot into the big leagues, but traditional laser range finders still have a use and at the very least make solving some of the problems easier.
This paper has important details on the XV-11 LIDAR
Kinect calibration technical details can be found here.
Submit your ideas or corrections in the comments. Clarifications available upon request.
A while back Gostai decided that the future of it's scripting language Urbi was opensource and decided to hold a contest to showcase Urbi's functionality.
First place was 2-high with an amazing 'Tower Defense NXT' project. Since the project is opensource there is enough documentation provided to build your own defense system and contribute to ongoing development.
The second place entry from Zappadoc shows of his racing simulator and interfacing Urbi to external hardware.
This looks like it could be an interesting hardware platform for developing ground station hardware for UAVs and other outdoor robots. The Nvidia Tegra chipset looks to be useful for 3D visualization and streaming video. Unfortunately, the version with the Pixel Qi display is currently sold out.
Personally, I'm hoping Pixel Qi will start making smaller displays, something the size of a Dell streak that can be mounted on a RC aircraft radio would be ideal.
Here at I Heart Robotics we are somewhat obsessed with delta robots, Stewart platforms, and other parallel manipulators. So as 2010 comes to an end we are looking for your help finding the best in this years parallel robot videos.
Email us your choice for parallel manipulator of the year, best DIY or best commercial parallel robot. Also we are currently lacking in holiday themed delta robot videos, so commercial vendors please send us a link to your sales videos of robots packing cookies, ornaments or fruitcakes.
The deadline for submissions is Midnight EST December 23rd, 2010
Now that 3D sensors have become widely affordable, there will be an increasing need to develop ways for robots to interact with 3D environments instead of 2D approximations. 3D mapping is going to be one of the more important uses for these sensors. At a practical level, the question quickly becomes, how are you going to deal with all of that data? Octrees are one solution.
This visualization by Jose Luis Blanco Claraco uses MRPT for efficiently rendering pointclouds of 11 million points. Which in terms of scale is only slightly more that a second worth of data from the Kinect at 640x480x30fps.
ROS seems to be helping with the team's productivity, but I am still looking for a paper to go with these videos for more details. Once again thermodynamics and energy storage look like the biggest performance limits facing quadrotor aircraft.
The PA-9 Micro Connector Crimper is back in stock at the I Heart Engineering store. It supports crimping the PH, SH, ZH and SHL series terminals from JST, The DF14 Series terminals from Hirose and the Micro-latch terminals from Molex. Many similar connectors can be crimped with die sizes of 1.0, 1.4, 1.6 and 1.9 millimeters
A new arrival, the PA-21 Universal Crimping Pliers support crimping larger connectors including the XH, NH, VH and PA series connector from JST, Mini-Fit connectors from Molex and Mate-N-Lok from AMP. Many other connectors can be crimped with die sizes of 1.6, 1.9, 2.2 and 2.5 millimeters.
Just to make sure we keep up with life on the exponential curve, Willow Garage is sponsoring a ROS 3D Contest. Prizes for the best, most creative and most useful things you can do with ROS and an RGB-D sensor.
* First Place: $3000
* Second Place: $2000
* Third Place: $1000
* "Most Useful": $2000
Rules and a picture of a turtle skateboarding here.
Hopefully these drivers should provide access to additional undocumented features, like turning off the laser on the Kinect. The hardware development kits will be quite useful as the power supply design should be simplified for robots. It will be interesting to see if there is any performance differences in the hardware between PSDK5.0 and the Kinect. A higher resolution and a longer range would be nice.
This is an interesting demo using MRPT to perform 6DoF SLAM to estimate the position and oritentation of the Kinect. While the performance looks good, it's clear that the 3D future of robotics will be computationally challenging. I think there is probably going to be a need for GPUs that work with embedded systems.
If you have an extra hour this Google TechTalk presents some of the ideas behind Urbi, though there have been some improvements since the talk. For example, the Urbi code base was recently opensourced with the GNU AGPL License.
Overall Urbi presents some interesting ideas for enabling control of the scheduler, and improving parallelism in a scripting language. The GUI tools look interesting and provide a graphical visualization of the state machines.
Today's featured product is the Pocket Bender, a great tool for bending aluminum, copper and brass sheet metal. The compact size makes it easy to store in your pocket, or in your toolbox.
The Pocket bender can be used to produce 90° bends, U-bends, and stair step bends. The bender can bend A5052 aluminum up to 1.5mm thick and 30mm wide, A1000 aluminum up to 1.5mm thick and 50mm wide. It also works on brass and copper sheets up to 1.0mm thick and 50mm wide.
Easy hand-held operation is performed by attaching the bender at the desired location and manually bending the part the the desired angle. The beveled edge of the tool allows for the production of accurate 90° bends. A hex key is conveniently included for tightening the tool. Order now.
Later in the week we should have how-to instructions for building your own desktop sentry robot.
The National Robotics Week Advisory Council wants a new slogan to help build awareness and get people excited about the events. Find out about submitting your ideas here. Entries are due by December 13, 2010.
The second annual National Robotics Week in 2011 will be from April 9th through the 17th. While it's probably a little early to think about if you are just planning on attending, now is the time to start planning if you want to host an event.
Our previous coverage of the 2010 National Robotics Week is also available.