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I have always been intrigued by robots, especially the kind that attempts to mimic human actions. This interest led me to try to design and develop a robotic biped that could imitate human walking and running. In this Instructable, I will show you the design and assembly of the robotic biped.
The primary goal while building this project was to make the system as robust as possible such that while experimenting with various walking and running gaits, I wouldn’t have to constantly worry about the hardware failing. This allowed me to push the hardware to its limit. A secondary goal was to make the biped relatively low-cost using readily available hobby parts and 3D printing leaving room for further upgrades and expansions. These two goals combined provide a robust foundation to perform various experiments, letting one develop the biped to more specific requirements.

The humanoid legs were designed in Autodesk’s free to use Fusion 360 3d modelling software. I began by importing the servo motors into the design and built the legs around them. I designed brackets for the servo motor which provides a second pivot point diametrically opposite to the servo motor’s shaft. Having dual shafts on either end of the motor gives structural stability to the design and eliminates any skewing that may occur when the legs are made to take some load. The links were designed to hold a bearing while the brackets used a bolt for the shaft. Once the links were mounted to the shafts using a nut, the bearing would provide a smooth and robust pivot point on the opposite side of the servo motor shaft.

Another goal while designing the biped was to keep the model as compact as possible to make maximum use of the torque provided by the servo motors. The dimensions of the links were made to achieve a large range of motion while minimizing the overall length. Making them too short would make the brackets collide, reducing the range of motion, and making it too long would exert unnecessary torque on the actuators. Finally, I designed the body of the robot onto which the Arduino and other electronic components would mount.”

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