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Series Elastic Actuator - CAD

A project log for 3D Printed Robot Actuator

A high speed and high torque robotic actuator using low-cost brushless motors, custom controller, 3D printed parts and bearings.

Paul GouldPaul Gould 10/13/2018 at 16:024 Comments

I have modified the base robot actuator to make it into a full robot leg for a quadruped. It has a parallel linkage with springs and 2 robot Actuators. This means that the spring direction changes from rotation to almost vertically linear when the leg is in the standard walking positions. Different strength springs can be swapped for testing, with the aim to store energy at the end of a jump cycle and use it for the next jump. It will also be used for efficient walking/running.

Everything rotates around the same joint, for the centre joint, described from top to bottom of the drawing.

Discussions

Paul Gould wrote 10/15/2018 at 13:03 point

Hi rudisoft, for me the SEA has two advantages. 1. It reduces the peak load seen by the 3D printed cycloidal gear when the foot hit the ground. 2. It allows the robot to jump

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rudisoft wrote 10/17/2018 at 06:34 point

Hi Paul, if the robot dog shall jump, you maybe want to check out https://www.youtube.com/watch?v=6hs-aHOc2Do&t=435s

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Paul Gould wrote 10/17/2018 at 10:56 point

That is very nice. I also found this https://www.youtube.com/watch?v=36ZjYJXDk0w

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rudisoft wrote 10/15/2018 at 10:35 point

From G.A. Pratt, and M. M. Williamson, “Series elastic actuators,” IEEE/RSJ Int. Conf. on Intelligent Robots and Systems (IROS), pp. 399-406, vol.1, 1995:

One of the most popular approaches is series elastic actuator (SEA), which has a constant spring between its actuator output and robotic link. While it remedies the high impedance of the actuators, it has the drawback of low stiffness and limited bandwidth that leads to degraded position control performance.

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