Seed Robotics describes the RH8D as an adult-size hand optimized for cobots. Its published specifications cover mechanics, feedback, payload and the software interfaces available to developers.

Hand mechanics

The company lists 19 degrees of freedom, including an opposable thumb and a full spherical wrist joint. Eight smart actuators are contained inside the unit, while three-segment fingers are controlled by smart actuators. Seed says the underactuated design is intended to balance fine control with conformance to an object's shape.

Feedback and tactile options

Seed says every actuator supplies real-time position, speed and directional current data, which can be used to infer applied force. Its product page also lists actuator temperature, overload status, PWM, a palm time-of-flight distance sensor and optional capacitive pads on the back of the palm.

For higher-resolution force sensing, Seed offers optional FTS tactile sensors with 1 mN resolution. The FTS-3 measures contact and shear forces across three axes, while the FTS-1 measures contact force on one axis.

Payload, weight and power

The published specifications give the RH8D a 2.5 kg vertical-pull payload and a 1 kg payload in three-dimensional space. The complete hand weighs 620 g, including its actuators, and accepts a 9 V to 24 V supply.

Seed also says an arm installation can bypass the hand's built-in wrist-rotation degree of freedom and use the robot arm's rotation instead.

ROS, simulation and connections

The software list includes URDF models for simulation, an open-source ROS package and Python support through PyPot. At the low level, the hand uses a UART serial interface compatible with Dynamixel Protocol 1.0 and 2.0.

For hardware connections, Seed lists UART over RS485 or full- or half-duplex TTL. USB is reserved for configuration and maintenance, while Bluetooth is optional for online maintenance and diagnostics. The RH8D manual further distinguishes the main Dynamixel-protocol connector from the USB or Bluetooth console used for diagnostics and maintenance.

Sources

This article was researched and fact-checked against the following sources: