This project presents a fully functional quadruped robot, designed with a focus on mechanical precision, movement versatility, and accessibility for 3D printing. The structure is composed of black and white PLA materials, using approximately two kilograms in total, and each component has been optimized for assembly, strength, and actuator compatibility. The locomotion system is composed of twelve strategically distributed brushless servomotors: three per leg, serving as ts at the two hips (hip1 and hip2) and the knee. The mechanical connection between the motor and the ts is achieved through 25T discs and 36-tooth GT2 pulleys, which allow for efficient transmission of motor torque. Each leg uses a 30 cm GT2 belt adjusted by a system of 7 mm bearings—four per leg to maintain belt tension and an additional one that acts as a for the knee t. In addition, two 37 mm bearings per leg are used to reinforce the stability of the main hip ts. To ensure proper attachment of the small bearings, four 3D-printed threads are integrated per limb, simplifying assembly without the need for additional tools. The knee ts feature heat sinks installed directly over the servomotors, allowing for extended operating sessions without the risk of overheating.
Regarding the electronics, the robot is equipped with a Teensy 4.0 microcontroller, responsible for precise control of the servomotors and communication with the sensors. This controller acts as the secondary brain of the system, complemented by a Raspberry Pi 4, which serves as the central onboard computer. This configuration allows for high processing capacity, ideal for running locomotion, vision, or machine learning algorithms. The Raspberry Pi is kept operational by a 5V, 3.2A voltage regulator, accompanied by a dedicated cooling system that ensures optimal thermal performance. A 5V relay is used to control the on/off operation of the brushless servos, while the main power supply is provided by a 10A DC-DC converter, ensuring stability even during complex maneuvers. All the necessary energy comes from a rechargeable battery, which powers both the Raspberry Pi and the Teensy, the motors, and associated peripherals.
On the sensory level, the robot includes a BNO080 inertial measurement unit (IMU) mounted on the central body, which provides precise data on the robot's orientation and dynamic state. This information is vital for maintaining balance and adjusting posture in real time. Additionally, each leg has a digital Hall effect sensor at the base, allowing it to detect ground and facilitate the implementation of reactive walking algorithms or haptic . Rubber surfaces are placed on the bottom of each leg to provide traction and reduce slippage on different types of terrain, which also improves overall stability during movement. The entire system is turned on and off using a physical switch integrated into the main housing, simplifying operation without compromising safety. The design's modular architecture allows for easy replacement or upgrade of any section without affecting the overall assembly, making it an ideal development platform for students, researchers, or robotics enthusiasts.
The quadruped robot was conceived not only as a mobile machine, but as a comprehensive learning platform, where each of its systems—mechanical, electronic, and control—has been carefully designed to work in harmony. From the selection of materials to the arrangement of each screw and bearing, efforts have been made to optimize both functionality and ease of manufacture. Thanks to the use of 3D printing, its parts can be quickly replicated or modified, adapting it to new research or experiments. The combination of brushless servomotors, powerful controllers, and high-precision sensors allows for fluid, reliable locomotion that is adaptable to different environments. This versatility allows the robot to not only walk, but also perform more complex tasks such as avoiding obstacles, adjusting to slopes, or even responding to commands based on vision or force detection. The design also includes future expansions, such as the use of cameras, artificial intelligence processing, or wireless communication with base stations.
Finally, the educational and experimental value of this robot is significant. It serves as a basis for exploring advanced robotics concepts such as inverse kinematics, multivariate dynamics, PID control, or neural networks applied to motion. It can be used in workshops, university classes, or research projects. The entire assembly can be performed with common tools and readily available commercial components, so it does not require industrial machinery or specialized knowledge for its construction. The robot represents a comprehensive, affordable, and highly functional solution for those wishing to enter the world of mobile robotics in a practical and professional way. Its attractive design, articulated behavior, and precise response make it an excellent choice for technical demonstrations, robotics competitions, or as a basis for new ideas and developments. The entire design is designed to be printed, assembled, programmed, and then started walking. Every detail has been carefully considered to offer a perfect balance between simplicity and sophistication.
