In the world of walking robots, six legs can give a device stability, while two simplifies the mechanics somewhat, but in the middle is the four-legged quadruped. It’s an intriguing design, with its own set of challenges, and in order to make a robot that could “imitate animals such as dogs and cats,” Technovation created a mostly 3D-printed version.
Technovation's project — which has a bill of materials under $60 — uses 30 3D-printed parts as well as a few others that are cut out with a laser. Printing time takes around 30 hours, forming four leg assemblies that move under the power of three servo motors each, with bearings that facilitate rotation. The bot is controlled by an Arduino Uno, along with a sensor shield for the servo connections, modified to accommodate an external 5V power supply.
Leg motion calculations can be handled via inverse kinematics, which is taken care of in the included code. It's able to walk in a forward direction and shift sideways too. It’s also capable of rotation in three axes, two of which (pitch and yaw) are shown in the video, and it can move itself up and down in the vertical direction as well. The build looks like a great platform for robotics experimentation, and can be equipped with an ultrasonic sensor, an MPU6050 IMU, or a variety of other sensing and control accessories as desired.