Meka Robotics is a San Francisco robotics startup founded by MIT roboticists Aaron Edsinger and Jeff Weber, of Domo fame. They have produced some pretty amazing products in the last few years, including the humanoid robot Simon that was recently featured on Hizook. As I'm somewhat familiar with these arms and hands, I'd like to share some more detailed information, including new videos of the torso and a more detailed look at the anthropomorphic hands. In particular, it is worth noting that all motors on the 7-DOF arms and 4-DOF hands employ series-elastic actuators (SEAs), a technology that offers natural compliance and provides torque measurements at each joint -- two very useful qualities for robots interacting directly with people. Be sure to read on for videos and many pictures. Updated Oct. 19th 2009: exclusive photos, product data sheets, and new videos added.
Content Added Oct. 19th 2009:
Aaron Edsinger gave me permission to post some new photos, product data sheets, and a few videos that will appear online on their "official" website in the coming week(s). Without further delay:
From the product datasheet:
The Meka A2 Compliant Manipulator is a lightweight seven degree-of-freedom force controlled arm. Designed to match the size and shape of a small adult, it is the ideal platform for researchers interested in manipulation for human environments. Engineered for compactness, safety, and reliability, the A2 system features high-strength forcecontrolled actuators, intrinsic physical compliance, zero-backlash Harmonic Drive earheads, and the Meka M3 real-time manipulation control system.
Each joint of the A2 manipulator utilizes a Series Elastic Actuator where a spring is placed between the motor and the joint. This physical compliance allows for high fidelity joint torque sensing. It also makes the arm “intrinsically safe” for human-robot interaction.
The A2 system is available in bimanual or single-arm configurations. It is plugand-play compatible with the Meka M3 control software and H2 hands.
The videos of this product are shown in the original post below.
From the product datasheet:
The Meka T2 Humanoid Torso is a two degree-of-freedom force controlled torso for a humanoid robot. It is design to increase the workspace of a Meka A2 bimanual manipulator system. Engineered for stability, safety, and reliability, the T2 system features high-strength force-controlled actuators, zero-backlash Harmonic Drive gearheads, integrated brake, and the Meka M3 real-time control system.
In addition to a single left-right pan degree-of-freedom, the T2 torso has a unique back design that allows for natural, expressive postures. Driven by a single actuator, the two mechanically coupled back joints create a curved profile as it leans forward or backwards.
The T2 torso is plug-and-play compatible with the Meka A2 manipulators.
Again, videos of this product are shown below in the original post.
From the datasheet:
The Meka S1 Humanoid Head is a nine degree-of-freedom robotic active vision head. Designed for a wide range of expressive postures, it is the ideal platform for researchers interested in human-robot interaction and social robotics. The S1 system features high resolution FireWire cameras in each eye, integrated DSP controllers, zero-backlash Harmonic Drive gearheads in the neck, and the Meka M3 real-time control system.
The S1 head includes a 3 DOF active vision camera system capable of quick saccades, smooth pursuit, and vergence. The 4 DOF neck and two independent eyelids allow for a wide range of expressive emotional
display such as happy, surprised, sad, and sleepy. Optional 4 DOF ears with RGB Led displays provide additional opportunities for emotional displays.
Meka can tailor the S1 design to your needs with the addition of customized head shells and additional degrees-of-freedom. S1 system is plug-and-play compatible with the Meka M3 control software and the A2 manipulators.
An early version of the head is shown in the Simon video below; I will try to acquire a video of more recent operation in the coming days.
From the datasheet:
The Meka H2 Compliant Hand is a fully-contained five degree-of-freedom humanoid hand. It has a is approximately human size with intrinsic physical compliance and haptic feedback, making it ideal for researchers interested in dexterous manipulation within human environments.
The H2 hand has a unique under-actuated design that provides remarkable dexterity. It has a total of 12 DOF controlled by 5 actuators. This also allows each finger to automatically adapt its shape to an object, thereby increasing the grasp contact area and stability. In addition, the fingers are very robust to impact and deformation due to their multi-durometer cast urethane construction.
Each finger is driven by a Series Elastic Actuator. By placing a spring between the motor and the finger drive tendon, the H2 hand achieves high-fidelity control of the tendon force. This physical compliance also improves robustness to impacts and the ability to maintain stable force-closure during grasping.
I love these hands! Playing around with them, they are quite rugged yet compliant, the movements are smooth and lifelike, and their human resemblance is uncanny -- I still can't believe they fit that many actuators and controller boards in such a small space. While research still needs to vet their manipulation capabilities, the following videos should wet your appetite.
Originally Posted Content:
First, I'd like to show some pictures of the Meka products.
||This photo (from EMM Precision) shows the Meka torso with two 7-DOF arms and a 2-DOF torso. All actuators are series elastic actuators (SEAs). It is worth noting that the overall dimensions are approximately the same as a 50% percentile human female, resulting in a very anthropomorphic robot (though some labmates contend that the bulging biceps make its gender ambiguous).|
|These photos show screenshots (video below) of the Meka Robotics anthropomorphic hand. If memory serves, there are 4 degrees of freedom: two for the thumb (opposing motion and closing), one for the index finger, and one (with a clutch) controlling the other two fingers. Obviously, this means that the fingers are under actuated. They are cable driven via series elastic actuators (SEAs) in the palm. They were built using a process akin to shape deposition manufacturing (SDM) using urethane thermoset elastomers of various compliance (among other materials).|
||This is Andrea Thomaz's robot Simon. As you can see, Simon sports a complete Meka torso, two of the anthropomorphic hands, and a expressive head whose internals were recently re-designed by Meka.|
||OK, the humanoid robot "Domo" isn't a Meka Robotics product, but it certainly illustrates Meka's pedigree. Domo had 29 degrees of freedom (DOF), including two 6-DOF hands. As far as I know, Domo was one of the most successful robots based on SEAs.|
|I keep mentioning "Series elastic actuators (SEAs)". I figure it is worthwhile to note that this type of actuator has a physical spring between the motor and load. This spring adds natural compliance to the actuator, and its deflection can be directly measured to determine the forces/torques being applied to the load (via Hooke's Law). If you would like to read more about SEAs, I'd highly recommend Matt Williamson's masters thesis.|
OK, on to the videos. First, a video of Simon.
While Simon shows off the entire Meka Robotics system, the newer videos below show the torso interacting with a human. [Thanks to PlasticPals for pointing out these videos.]
You'll note that Aaron had little fear of grabbing and interacting with the torso. Based on my ancillary experiences with these arms, they appear to be operating in gravity-compensated position mode. In this mode, torques are being commanded by a real-time Linux system at 1kHz over EtherCAT so as to maintain a fixed position (determined by encoders on each motor). Meanwhile, high-speed control loops running at ~10kHz maintain the set torques at each joint. Very impressive design and implementation!
Now on to the Meka Robotics anthropomorphic hands. As you'll recall from the Hizook post about the Dustpan robot, under-actuated end effectors can be quite effective. The video below is just a quick snippet from New Scientist's coverage the International Joint Conference on Artificial Intelligence (IJCAI).
I'm going to have to defer any additional information and videos until I get more explicit permission (from the powers that be) to publicly disseminate. More will follow, that I promise -- Meka designs some quality products!