The 2dof leg consists of two identical actuator modules, the lower leg and a foot with a optical contact switch.
The actuator modules are capable of continuous output rotation and there are no mechanical end stops on the leg.
Since there are wires routed through the hollow shell structures the output rotation should be limited to 3 turns in each direction in software.
The segment lenght is 160mm and results in a neutral standing height of 240mm (at 45 degree hip angle and 90 degree knee angle).
Leg Dimensions - the neutral standing height of the leg is 240mm
The actuator module details are described here -> Actuator module
The foot contact switch and lower leg details are described here -> Foot Contact Switch
The leg can be used for experiments and measurements with external sensors in the leg test stand. -> Leg Test stand
4 of the leg modules can be used to assemble a 8dof quadruped robot. -> Quadruped Robot
The leg segments are stacked and can perform multiple rotations.
The shell of the actuator module consists of two parts that are connected by eight M2,5 screws.
The shell structure supports the motor, encoder and the bearings for the transmission and the output joint.
We recommend to print the shells on a SLS 3D printer. (selective laser sintering printer)
We use Helicoil threaded inserts for increased stability.
We upgraded the shell design for improved stability.
We recommend to use the new version of the 2dof leg (leg_2dof_v2).
- Actuator Module Shell Base Outdated - 28g -> STL file
- Actuator Module Shell Cover Outdated - 16g -> STL file
Counterclockwise when looking at the motor from the top
Clockwise when looking at the robot from the side
Drawing circles with a 2 dof leg module, developed during a high school student project at New York University.
Credit: Brandon G. Knox
Leg mounted at 45 degrees and in parallel to the table
The 3d printed table attachment can be used to attach the leg to the table and orient it at 45 degrees or in parallel with the table.
The table attachment was designed to print without support on a FDM printer (fused deposition modelling printer). The recommended printing direction is the positive z-axis direction of the STL file.
- Table Attachment -> STL
- To get an better overview of the assembly you can view this pdf file
- I recommend downloading the free eDrawings viewer for Windows, Mac, iOS and Android here.
- The eDrawing Viewer Software allows you to open and explore this easm cad assembly file
Open Dynamic Robot Initiative - Webpage
Open Dynamic Robot Initiative - YouTube Channel
Open Dynamic Robot Initiative - Forum
Open Dynamic Robot Initiative - Paper
Hardware Overview
Software Overview
Felix Grimminger
BSD 3-Clause License
Copyright (c) 2019-2020, Max Planck Gesellschaft and New York University