Poppy, the subject of this article, is a human-like robot engineered with an open body, open software, and has a good proportion of human being. The open-source platform is a good option for researchers, students or hobbyists to start their own project on a biologically inspired kit.

The project starts as a challenge and finished as a more accessible and easy-to-use prototyping platform. The project is not 100% finished, since the researchers together with a community of fans works to bring new functionalities and a lower price for a wide audience.

The Poppy was born in the Inria Flowers Lab (Bordeaux-France), and the idea is to provide a hackable and the low priced humanoid platform for a wide range of fields including here scientist, students, artists, hackers, or hobbyists. A modular system, 3D printed components, and off-the-shelf components are a good start to build a humanoid robot for large audiences.

The Puppy is opened for both hardware and software sides, and to cut the price of the final robot several parts are printed using a simple 3D printer. An anthropomorphic body has to be flexible and reproduce a human body. Poppy can reach this design with bent legs and multi-articulated trunk, plus a soft body with good proportion of human being, robustness, agility and stability during the walking.

An accident may break a part of the robot, and with a standard body a random incident may raise the final price of your project. Using off-the-shelf components such as electronics and motors together with a 3D printed body is the best solution to cut the cost and replace the components with problems or add other custom parts.

Optionally, for an improved interaction can be added several other components. The brain of the Puppy can be a Raspberry Pi able to control all the 16 force-sensing resistors, an IMU sensor, display emotions on the LCD screen, process images from two HD cameras, and interpret the sound captured with a stereo microphone.

Optimized for biped locomotion, the open-source robot is modeled after the human body with bent legs able to increase the agility and stability during walking, as well as 5 motors for a multi-articulated trunk able to reproduce the main degrees of freedom of the human spine, and a soft body for a wide range of operations. A semi-passive knee has the role to keep the leg straight during the support phase without additional electric motor.

According to the manufacturer, the Poppy is a cheap robot in this field. Compared with other several open-source human like robots, Poppy is probably an affordable robot with a modular body and popular components. But – because always is a ‘but’ – a final price of 7500€ is still a high price that has to be cut even more to talk for a real cheap solution of a humanoid robot.

Specifications

• Dimensions: H:84 W:25 T:10 (cm);
• Mass: 3.5 kg;
• Motors: 21x Robotis Dynamixels MX-28, 2x Robotis Dynamixels MX-64, 2x Robotis Dynamixels AX-12;
• Optional Sensors: 16x Forces sensors (FSR), 2x PS Eye, 1x IMU (9DDL);
• Optional Screen: 4.3-inch LCD 480 x 272 px;
• Optional brain: Raspberry Pi;
• Cost: 7500-8000€;
• Assembly Time: 2-3 days;

About the Robotis Dynamixels MX series

The use of Robotis Dynamixels MX is not a coincidence since this top-tier actuators are designed for researchers and universities. From robotic competition to research lab, these actuators are engineered specially to provide an advanced bracket system for building accurate robotic limbs. The actuators have a dedicated on-board MCU where you can adjust the speed, torque, and the response, while a feedback system return the position, load, voltage, and temperature.

Comparison

Let’s see where is the price of Poppy compared with several other humanoid robots:

• Acroban: $9,000;
• Poppy: ~$10,000(7500€);
• Darwin-OP: $12,000;
• Nao: $12,000;
• Nimbro-OP: $22,000;

PYPOT Library

PyPot is the library written in Phyton and developed to control the Dynamixels servos. This library allows you to develop easy and fast programs on Linux, Windows and Mac OS.

Documentation and Tutorials

Probably your expectation is to have available a sea of tutorials and documentation, but I must admit that the whole community has to work hardly to build a database of tutorials and projects based on the open-source Puppy robot.

I would like to end this article in an optimistic way, but I cannot overlook few features that have to be changed. Most probably, the final version will be more independent by a power supply since the actual version of the Poppy is powered through cables and it doesn’t have any space for batteries. Once the batteries will be located in the robot body, the weight will be increased and the entire structure will be affected once with the efficiency and several other features.

The printing solution is a good one, but is not a fully printed robot. The most expensive parts are the actuators, sensors, Raspberry Pi, and many more parts, which are bought from traditional manufacturers.
The final price is a good one compared with other humanoid robots designed with an opened architecture and able to be used in research and educational areas.