High-accuracy desktop academic robot

Dual-arm SCARA educational robot

General description

DexTAR (Dextrous Twin-Arm Robot) is a three-axis dual-arm SCARA robot developed for education and training purposes. It is essentially a five-bar mechanism. The fundamental five-bar linkage is the best pedagogical example of a parallel robot and is ideal for teaching various robotics concepts. Although DexTAR is an educational robot, it meets industrial standards of performance. It is constructed of precision-machined aluminum, and driven by two 90 W maxon® servomotors and one stepper motor linear actuator. The robot is also equipped with high-resolution encoders.

DexTAR comes with an electromagnet for picking up steel balls, however a custom-made end-effector can easily be installed. This stylish desktop robot meets all robot safety standards and is equipped with an interlocking protective cover (not shown). DexTAR is fairly compact, portable, and affordable, and does not use a cumbersome teach pendant.

DexTAR is programmed exclusively offline with its own simulation and offline programming software, DexTAR Sim, which runs on Windows and is available for free. Prior to simulation, a program is written by the user, using a simple custom robot scripting language, and then compiled. The compiled program is ready for simulation or to be uploaded from the computer to the robot's internal memory via a USB cable. Programs residing in the robot's internal memory are executed through the robot's touch screen (no computer connection required).

Teaching materials are included in the User's Manual to facilitate the incorporation of DexTAR into existing courses.

Download User's Manual Download PDF

Download DexTAR Sim Download PDF

In-depth description

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The JavaScript applet on the right provides a simulation of the actual desktop robot in the form of a game. The unique feature of DexTAR is that its four links are of equal length (90 mm, axis to axis). This makes its workspace, the lens-shaped area enclosed by the two circular arcs, free of holes.

DexTAR has two assembly modes which differ in the sign of the angle between the distal links. When this angle is 0° or 180°, DexTAR is at a Type 2 singularity. Since a parallel robot is uncontrollable near such singularities, DexTAR's controller avoids most of them, but it can change assembly modes by fully folding one of its arms and rotating it.

DexTAR's workspace is limited by the potential for collisions between the proximal links. Fortunately, the robot has four working modes, which are the possible robot configurations for a desired end-effector position. A working mode can be changed by passing through a Type 1 singularity, which is a configuration where at least one of the two arms is fully extended or fully folded. For each combination of working mode and assembly mode, the corresponding workspace is shown in blue. Switching working modes and assembly modes provides DexTAR with access to the complete lens-shaped area. For a current robot configuration and a desired end-effector position, DexTAR's controller automatically chooses the shortest trajectory.

Technical data

Mechanical specifications

Footprint 435 mm × 420 mm (17.1 in × 16.5 in)
Weight 10.2 kg (22.5 lb)
XY Workspace Larger than a circular area of diameter 242 mm (9.5 in)*
Axis 1 & 2 encoder resolution 0.011°
Axis 1 & 2 max speed 720°/s
XY max linear speed 300 mm/s (11.8 in/s)
Z axis stroke 19 mm (0.75 in)
Z axis resolution 0.025 mm (0.001 in)
Z axis max speed 120 mm/s (4.7 in/s)
Position repeatability 0.025 mm (0.001 in)
*The actual workspace is the lens-shapped area shown in the above JavaScript simulation.

Electrical specifications

Power 24 V / 9.17 A (external power supply with country-specific power cord)
Touch screen 480 × 320 pixels
Full color 3.5 in display
Tool interface 1 output 24 V
(for the electromagnet)
Communication USB 2.0 port
(for uploading programs)
Connectivity Connector for third-party control card*
*Note: The warranty is void if a third-party control card is used. Contact us for further details.

An optional wheeled transport case (NANUK 960) is available as an option.

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