MDS image Photo credit: Mikey Siegel

Science fiction it isn’t, though US-based Xitome Design’s MDS robot has certain out-of-this-world qualities to its facial expressions, hand gestures and speech. It brings to mind the likes of Star Wars C-3PO… but with the potential to be a great deal more adept, and affable!

The MDS (Mobile-Dextrous-Social) is a robotic platform that is able to communicate verbally and non-verbally. Designed primarily with Human Robot Interaction (HRI) research in mind, it was the brainchild of Prof Cynthia Breazeal, Director of the Personal Robots Group at MIT Media Lab, who has pioneered the field of human-robot interaction. With the ultimate research goal being to develop human to robot interaction to a level akin to the way humans interact with other humans, potential applications for these robots include care of the elderly, healthcare and education.

Breazeal commissioned Xitome Design to build ‘Nexi’, a first version MDS for a joint collaboration project with UMASS Amherst. Xitome Design – a long-standing Kvaser customer – is now commercialising the project and, as a result, leaders in robot research like the US Naval Research Labs also use it. There, capabilities such as gesture recognition and visual processing are being used to develop robot self-learning techniques. 

At the core of this robot is a series of high-density motor controllers designed by Xitome and based on Denali hardware. A dedicated microcontroller and power amplifier is employed for each control channel. With communication between motor control units needed in a way that achieves flexible position control in a decentralised manner, Xitome Design uses a 1Mbit Controller Area Network (CAN) bus to daisy chain the microcontrollers together. This results in just two wires to provide motor control, power and CAN communication to the head.

Kailas Narendran, Xitome Design’s co-founder, explains: “The head alone has 19 motors. After you take up space with motors, metal, armatures, cables, etc., there’s just tens of cubic inches for all the motor control hardware. Running lots of cables through the neck isn’t possible because it needs to have a high range of motion and degree of freedom.”

Kvaser’s PC104+ dual channel CAN card can be found in the computational stack in the base of the robot, where all motor control and position feedback sensing take place. In the US Navy’s MDSs, a higher-powered computer on the back handles vision processing. Meanwhile, Kvaser’s CANLib has been incorporated into Xitome Design’s own API to interface to the bus. Of Kvaser’s input, Narendran says: “There were lots of software and hardware implementation questions that we worked on with Kvaser and they were very responsive and helpful.”

Asked why Xitome Design chose CAN above other communications protocols for this application, Narendran says: “It’s a very robust and fast hardware protocol, with built in error detection and re-transmission, so good for noise immunity performance. In addition, the hardware implementation is relatively simple and compact and it’s daisy chained nature helps with cabling issues.” Narendran goes on to explain that fault isolation is achieved through CAN and the MDS’ inherent design. If a channel fails, its communication failures are isolated via the CAN mechanism, whilst other control failures are isolated by the natural separation of control to a dedicated microcontroller.

Whilst the hardware for such robots is already well developed, there’s some catching up to do to achieve the vision of human-like communication and self-realisation on the software side. Notes Narendran: “Our hardware has enough degrees of freedom to provide a close approximation of many emotional gestures. It has lots of sensors and computation capabilities, multiple video cameras, a 3D imager and a microphone array that theoretically allows for audio localisation capabilities. The software is where the really meaningful side of robotics is taking place, but at this stage, it is far behind what the hardware is capable of.”

Whilst high degree of freedom humanoids might seem a niche market just now, human-robot interaction is an emerging research field with huge implications for society as a whole. Narendran says that Xitome Design has had commercial interest in its robots, but for now, the company is concentrating on the research market, in addition to offering its high-density motion control and electromechanical systems expertise wider a field. 

So while it may be some time until we encounter friendly humanoids on a regular basis, thanks to Xitome Design and the research organisations it serves, that day may come a lot sooner than you think.

hyperlink to video: http://glue.ccs.nrl.navy.mil/aic/rsr_001/final-grain-auto.swf

A Naval Research Lab researcher is shown playing a cup and ball game with the robot. The footage demonstrates that the robot comprehends the gestures made by the researcher and its ability to develop a concept of reality based on the visual data it obtains, from which it can draw conclusions.]