Interbotix ViperX-300 6DOF

A 6DOF robot arm from Interbotix X-Series Arms with the utmost reach of 750mm and payload of 750g, Dynamixel servos, and customizable end effectors suitable for education and research.

Specifications

Degrees of Freedom6
Reach750mm
Total Span1500mm
Recommended Workspace1050mm
Accuracy1mm
Working Payload750g
Power Supply12V5A
Total Servos9
WaistMin: -180, Max: 180
ShoulderMin: -101, Max: 101
ElbowMin: -101, Max: 92
Wrist AngleMin: -107, Max: 130
Forearm RollMin: -180, Max: 180
Wrist RotateMin: -180, Max: 180
GripperMin: 42mm, Max: 116mm
DYNAMIXEL XM430-W350-T
MCUARM CORTEX-M3 (72 [MHz], 32Bit)
Position SensorContactless absolute encoder (12Bit, 360 [°])
MotorCoreless
Baud Rate9,600 [bps] ~ 4.5 [Mbps]
Control AlgorithmPID control
Resolution4096 [pulse/rev]
Gear Ratio353.5 : 1
Stall Torque4.1 [N.m] (at 12.0 [V], 2.3 [A])
No Load Speed46 [rev/min] (at 12.0 [V])
FeedbackPosition, Velocity, Current, Realtime tick, Trajectory, Temperature, Input Voltage, etc
DYNAMIXEL XM540-W270-T
MCUARM CORTEX-M3 (72 [MHz], 32Bit)
Position SensorContactless absolute encoder (12Bit, 360 [°])
MotorCoreless
Baud Rate9,600 [bps] ~ 4.5 [Mbps]
Control AlgorithmPID control
Resolution4096 [pulse/rev]
Gear Ratio272.5 : 1
Stall Torque10.6 [N.m] (at 12.0 [V], 4.4 [A])
No Load Speed30 [rev/min] (at 12.0 [V])
FeedbackPosition, Velocity, Current, Realtime tick, Trajectory, Temperature, Input Voltage, etc

Overview

With their accurate form, robots are capable of working precisely in automated environments requiring precision and accurate outcomes—consequently reducing human physical workload. Among many robotic applications include real-time object recognition, where the combined power of computer vision and artificial intelligence gains the ability to identify objects.

The technology likewise utilizes machine learning and deep learning. Despite this advanced function, there is a challenge in researching these technologies as they require machines for code implementation and data gathering. The need for hardware and lower-level code in completing a machine likewise arises.

A member of the Interbotix X-Series is the robotic arm ViperX-300 6DOFm featuring Robotis’ DYNAMIXEL X-Series Actuators. As a key addition in research facilities, classrooms, and laboratories, ViperX-300 6DOF supports demos, instructional videos, MoveIt, MATLAB, ROS, and Gazebo. This robot arm is suitable for machine learning, AI, and vision-based pick and place.

Design

The fully-tested ViperX-300 6DOF comes fully-assembled in a rigid 20mm x 40mm extruded aluminum housing. The armrests on the industrial grade bearing for stability and accuracy. A transparent acrylic shield covers the electronics, freeing them from debris and impact coming from the arm itself.

6 Degrees of Freedom

ViperX-300 6DOF, as the name implies, features 6 degrees of freedom on top of a 360-degree full rotation ability. This number of DOF increases maneuverability. While the 6DOF arm can control every factor independently, at least one must be compromised with lower DOF arms.

Dynamixel Servos

The robot arm utilizes DYNAMIXEL XM540-W270 and DYNAMIXEL XM-430-W350 servos. At 12.0V, the former has a 10.6Nm stall torque and no load speed of 30 rev/min, while the latter has a 4.1Nm stall torque and no load speed of 46 rev/min. These servos provide high resolution at 4096 positions, definable PID parameters, positional feedback, and monitoring. Likewise, it makes voltage levels, compliance settings, and load accessible to the user.

The device achieves trajectory smoothing through the multiple registers in the smart servos, which set velocity setting, acceleration limits, fine-tuning, and PID gains. Meanwhile, DYNAMIXEL servos host low-level libraries, abstracting away serial communication layers—paving more higher-level coding time for developers.

Range & Payload

Measured from base center to gripper, the arm extends a 750mm horizontal reach for an overall 1500mm span. This payload is the maximum weight for normal working circumstances defined as the arm's ability to lift objects repeatedly at about half its extension without failure.

U2D2 Controller & Power Hub Board

Robotis’ DYNAMIXEL U2D2 powers ViperX-300 6DOF, granting the device access to DYNAMIXEL and ROS Wizard Software. The USB to TTL converter serves as the U2D2 controller, which allows DYNAMIXEL servos control via a computer.  The 6 port 3-pin XM/XL power hub can split the DYNAMIXEL daisy chain into five separate chains while simultaneously powering them up. Likewise, the 2.1x5.5mm female barrel jack and screw terminals add more functionalities.

AprilTag

The visual fiducial system AprilTag is useful in various tasks, like robotics, augmented reality, and camera calibration. An ordinary printer can create the targets, allowing the AprilTag detection software to compute orientation, precise 3D location, and tag identities relative to the camera.

The C language implements the software library with no external dependencies. Its design targets easy inclusion in other applications and portability to embedded devices so that even cellphone-grade processors can achieve real-time performance.

3D Print Custom End Effectors

The X-series gripper carriages provide quick and easy changing of the fingers for various projects. The gripper’s minimum grip width is 30mm and a maximum of 74mm. CAD files for the grippers are downloadable, making customization endless so long as it is designable and 3D printable. The arm also includes a sticker-backed form for increased gripping strength and relieved stress on the servo.

Reparability

As a work-on design, the arm keeps the manipulator functioning—allowing easy swapping of motors and arm length adjusting. Parts for future repairs are also kept in stock to minimize downtime.

Optional Upgrade kits

Pre-configured with Ubuntu MATE 20.04, the RPI4/PS4 Bluetooth Control Set, ROS Noetic, and Interbotix PI ROS packages allow plug-and-play control of the X-Series arms. This option is available for users desiring remote control of the manipulator. The kit setup works with every Interbotix X-Series arm.

Adding the Intel D415 RealSense Depth Camera is the Vision kit upgrade. The upgrade also adds a camera stand and colored blocks meant to work with the vision-based ROS packages. The add-on enables features such as object sorting or tracking, pick and place, and detection.

Software

Every X-Series arm operates on a similar central open-source repository, which makes concept transfer over platforms easier. Several packages also ease working with the arm, like the ROS (Melodic and Noetic) and the ROS2 (Galactic, Humble, and Rolling). Such packages contain full meshes, simulation (Gazebo), motion planning (MoveIt), and URDFs—a driver node controlling the physical arm and publishing joint states. Meanwhile, IRROS, Interbotix Research Robotics Open Standard, allows smooth integration of lower-level actuator ROS wrappers into higher-level codes.

Additionally, the manipulation software MoveIt is free for commercial, industrial, and research, given its BSD license. On the other hand, Gazebo, free software in an active community, can accurately and efficiently simulate robot populations in complex environments. Lastly, MATLAB-ROS and Python-ROS APIs sit about the ROS layer, granting control of the arm despite lacking familiarity with ROS. Both APIs have the same functionalities for interacting with the arm kinematics, operating mode, and timing parameters, among others.

References

Trossen Robotics

Wevolver 2023