The world’s first two-legged consumer robot, “nuvo” has been launched by ZMP, a Japanese robot venture company. The robot has highly-sophisticated movements — it can get up by itself from a fallen position — and a human-like friendly look and personality. Internally, it is an integration of cutting-edge technologies, especially the main CPU section. Its CPU board "heart" achieves high performance, consumes low levels of power to suppress heat, and is small, about the size of a business card. Renesas supported ZMP in speeding up the development and marketing of nuvo, aiding the design and manufacture of the SH7760-based CPU board, as well as providing an optimum environment for software development.

A robot that resembles a human and walks on two legs is called a "humanoid robot." The first humanoid robot for consumer use, a product from ZMP Inc. called "nuvo," has a body assembled with a head, two arms and two legs. It looks very much like a human being and can even make some charming movements in the same way a human can. The name derives from the French word "nouveau" (new). Only 39cm tall, the nuvo robot is a tiny, humorous invention (see photo 1).

Although nuvo might be appear to be just a toy, it's far more sophisticated than that. The robot comprises a cutting-edge mechanism integrated with a whole range of the most advanced technologies. Its biggest feature is an advanced control system that stabilizes balance and walking coordination so that the robot can traverse uneven surfaces. Without such a good walking stabilization control system, it couldn't maintain balance and would readily fall over. The nuvo robot keeps a good walking balance and will remain upright under many types of terrain. Moreover, should it fall down for any reason, it can get up by itself and resume walking.

Furthermore, nuvo has a voice recognition system that can recognize certain commands. Saying a command such as "nuvo, go forward", among others, will prompt the appropriate movement. The robot can also be operated remotely via a remote control device or a cell-phone.

Features of the nuvo robot include the ability to capture images using a built-in camera and transfer the pictures to a PC via a LAN. It can even send then via the Internet so they can be viewed on a cell-phone.

ZMP is a venture company specializing in humanoid robot development. The business was triggered four and half years ago by the ERATO Kitano Symbiotic Systems Project, the robot research and development program conducted by the Japan Science and Technology Corporation under the Ministry of Education, Culture, Sports, Science, and Technology. ZMP was established to pursue further humanoid development within a business concept based on the "PINO" robot developed by the Kitano project.

Ever since, ZMP has been independently engaged in the development of PINO-based humanoid robots. First, the company created the "PINO ver.2" humanoid with the same exterior, but an improved internal mechanism, including a walking stabilization control system. Next, in March 2004 it created "e-nuvo" (see photo 2), a teaching tool for studies of humanoid robots that is sold with a textbook and special-purpose software to universities and other educational institutions. "We have a proven record of success, with more than 100 sets sold," said Ms. Imanishi. "For example, the Nippon Institute of Technology has introduced 30 e-nuvo sets to the Department of Mechanical Engineering of the Faculty of Engineering."

The body of e-nuvo is similar to the lower part of the human body, having two legs and thighs and a waist. The electronics controlling the robot's walking coordination consists of a main CPU board that processes the calculations needed to provide steady walking movements on two legs, and sub-CPU boards (motor drivers) that operate motors to adjust joint angles for optimal walking movements. The tasks of the main CPU and sub-CPUs are executed by a distributed processing system.

"In the first PINO robot, one microcomputer centrally controlled 26 R/C servo motors. Many commercially-available parts were used because it was developed for research purposes," explained Mr. Kato. "However, for the version 2 model we engineered our own distributed processing control system and asked a motor manufacturer that supported our efforts to build custom motors to our specifications. As a result, we achieved a great improvement in walking stabilization and mechanical precision."
* R/C: radio control

The e-nuvo robot has one main CPU board and three sub-CPU boards. The main CPU and one sub-CPU are mounted in the waist section. The other two sub-CPUs are fitted to the left and right thighs. Each sub-CPU can operate four motors. All processors are Renesas microcomputers: an SH7055 SuperH-series device with a 40MHz 32-bit SH-2E RISC core for the main CPU, and H8S/2612 16-bit H8S-series CISC chips for the sub-CPUs. They were chosen because they met ZMP's specifications and were readily available. "When user wants a semiconductor only in a small quantity," explains Mr. Kato, "it is very important that the device be readily available in the market."

When ZMP launched the e-nuvo robot, it also unveiled the prototype of the nuvo consumer humanoid. The subsequent development efforts that fully-commercialized the product made few changes to the prototype's exterior design. Being aimed at consumer markets, the nuvo robot offers good operating performance and has an exterior carefully designed to ensure safety and reliability. For instance, all parts, including cables and motors, are concealed.

It is quite characteristic that the exterior of nuvo reflects close consideration for structural materials. The exterior design progressed in parallel with the structural design. "When one type of design precedes the other, conflicts are likely to arise that cause complications," Mr. Kato said. "Our designers and engineers put their brains together to create an affectionate appearance, while seeking a sensible way to accommodate all the functions we wanted to offer."

Like e-nuvo robot that proceeded it, nuvo is equipped with a walking stabilization control system consisting of a main CPU board and sub CPU boards (see diagram). However, the main CPU board had to be changed because it wasn't suitable for a mass-production product, nor did it meet the main CPU board specifications for nuvo, which were much more demanding. After comparing boards from three different companies, ZMP chose a special SuperH microcomputer board by Renesas. "We compared the candidates in all aspects: total fulfillment of all functional specifications, development period and speed, pricing, etc. Then we decided to adopt the Renesas CPU board," Mr. Kato commented.

The main CPU board of nuvo actually comprises two printed-circuit boards. To fit into the robot's body, it had to be no larger than a business card and no more than 2cm high. To accomplish that, our engineers installed most of the semiconductors using BGA/CSP packaging technology and achieved a high-density layout on the board with cleverly arranged wires and connectors. The microprocessor, an SH7760 SuperH RISC chip with a 200MHz SH-4 RISC core, connects to two 256Mbit "superAnd" type flash memory devices.

The SH7760 is a high-performance processor capable of both control and application processing. In addition, it incorporates many periphery functions, such as a floating point arithmetic circuit, CAN bus interface, and USB host interface. "One of our requests was to install floating point arithmetic hardware and a CAN bus interface onto the main CPU board," said Mr. Kato.

Generally speaking, the floating point arithmetic circuit is indispensable for robot control processing. When the robot is in operation, the main CPU board constantly registers the current angle of each joint to calculate the right angle for the next movement. Then it sends signals to the appropriate sub-CPU motor drivers that control each joint. Such floating point processing must be done quickly, and that requires dedicated hardware. Also, the walking control system adopts distributed processing, so high-speed communication between the main CPU and sub-CPUs is a must, and the CAN bus meets that requirement. The key to the way the humanoid robot achieves natural walking coordination on two legs is the use of a system design that implements processing and motor control separately.

A big advantage for the SH7760 is its low power consumption, because the nuvo consumer humanoid does not have a fan, nor does it have a vent to release heat. This is a deliberate measure to ensure safety and reliability for domestic use. Moreover, the robot isn't even allowed to have a heat sink, so heat control was a major design issue. The power-efficient SH7760 was an optimum choice due to these restrictions.

To design software for the main CPU board, the Solution Engine produced by Hitachi ULSI Systems, a partner of Renesas, was used as a platform. It contributed greatly to the acceleration of the entire development process that led to the production of nuvo.

To advance its robotic technology and enhance future humanoid products, ZMP is seeking further improvement in areas such as controlling heat generation and boosting processing rates. One suggested idea is to reduce the packaging space by half by putting the microcomputer and memory chips into one package. At Renesas, our engineers taking on this and other challenges by applying our expert knowledge and vast technological resources in chip design, production, and packaging.