Robot Dog Part 1: Leg Day
Aaed Musa, a robotics creator, explains how he designed, built, and programmed a test leg for T.O.P.S., his quadruped robot inspired by Boston Dynamics’ Spot.
In this talk
- 0:13
Designing the leg and its kinematics
Musa names the robot T.O.P.S., short for Traverser of Planar Surfaces, and describes three joints for moving its foot in 3D space. He derives QUICK, or Quadruped Inverse Kinematics, to convert a target foot position into joint angles, then uses the equations in CAD to test foot movement.
- 1:58
Building the actuators and leg
After about a week of design work, Musa integrates parts of each joint into its actuator to simplify assembly. The knee uses a belt and idler pulleys, while limit switches provide a home position for each actuator. He uses carbon fiber tube for the forearm and a printed foot for this test build.
- 5:02
Power, control, and motion tests
Each actuator pairs a brushless motor with an ODrive controller, powered by a 6S battery and connected to a Teensy 4.1 over UART. Musa programs homing and uses an Arduino library to turn foot coordinates into actuator positions. He tests rectangular and sinusoidal steps, sideways movement, push-ups, and circular paths; the sinusoidal step looks smoother.
- 8:17
A direction error and next revisions
The abduction actuator interprets increasing angle in the opposite direction from the kinematics equations, causing a motion error that breaks a 12-millimeter-thick part. Before designing the full robot, Musa plans to consider CAN bus communication, reduce actuator weight and leg torque, and make the limit switches less visible. He says the CAD, code, and technical specifications are open source on ieemuso.com.
Briefs summarise talks and interviews; timestamps open the video at that moment. Claims in a talk are the speaker's own.