CAD and STL files for the various OpenHand hardware designs. Complete documentation, including assembly directions, can be found at the OpenHand website

Based on the original SDM Hand, the Model T is the OpenHand Project's first released hand design. the four underactuated fingers are differentially coupled through a floating pulley tree, allowing for equal force output on all finger contacts. All finger joints are flexure-based, made with Smooth-On polyurethane. An alternative design with pin-based base joints is also available.

The Model T42 is a two-finger, two-actuator hand designed for more dexterous planar tasks. It is still capable of underactuated, adaptive grasping, but the additional actuator makes it capable of some in-hand manipulation primitives as well as precision grasping. Dynamixels can be replaced by Power HD servos in this design.

The Model O is a three-finger, four-actuator hand designed to replicate the capabilities of commercial hands such as BarrettHand, RightHand Robotics' Reflex Hand, and Robotiq's 3-Finger Adaptive Gripper. Each underactuated finger is independently controlled, while a fourth actuator controls the adduction/abduction angle between two of the fingers. This allows the hand to transition between spherical-grasping and power-grasping configurations.

The Model M2, short for Multi-Modality Gripper, is a minimalist gripper with a single underactuated finger and a library of modular thumb designs. It can only require a single actuator with very simple assembly requirements. Each thumb design can enable a different grasping behavior and allows for faster, more versatile design iterations.

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To start, open up the assembly files for the various hands. Complete sets of .stl and .step files should be in each hand directory. Edrawings files are also available for those who do not have Solidworks. A free viewer for eDrawings is available at http://www.edrawingsviewer.com/

Things to note:

• Most Solidworks parts have dependencies on other parts. To avoid warnings/errors when opening assemblies, be sure to have "Load referenced documents" set to "All" in Options>>External References
• Many of the assemblies use Configurations extensively to cut down on the number of CAD source files I have to maintain. Be sure to check them out!
• More details about our approach to CAD for this project can be found in our CAD Guide