Low cost bench-top six-axis general purpose articulated robot arm

R12 six axis with gripper
shown with optional electric gripper



The R12-six is a complete self-contained six axis vertically articulated robot arm system designed as a cost effective solution for bench top automation. Applications include testing, sample handling, machine feeding. The hand terminates in a mounting plate for grippers, vacuum cups etc.

R12-six is a very low cost entry to robotics, fast, accurate and reliable and easy to program yet capable of the most complex tasks. It has a useful 500mm reach. R12-six is a technological breakthrough in bench top robotics. Based on the R12-500 it is a 6 axis articulated robot arm with a 500mm reach. It employs new light weight, high efficiency digital motors driving through steel reinforced polyurethane timing belts for the first 5 axes.

The 6th axis is a unique way to make 6 axes optional, being an add-on module with a miniature stepping motor driving through a Swiss anti-backlash gearbox.
Incremental optical encoders are optional on the first 5 axes providing exceptional integrity (see below).

Do not let the low cost mislead you - this is not a hobby robot. It is a professional tool made to industrial standards of quality, reliability and performance, machined from solid alloy and finished with aesthetic acrylic covers. The system is supplied complete with controller, all cables, connectors, software, comprehensive manuals, ready to unpack and use immediately.

The K11 robot controller uses a partnership of MPU and DSP processors and compact high voltage micro-stepping drives providing both speed and precise control and is provided with a simple intuitive teach pad. The controller can also interface with or even control other equipment at the same time as the robot. Software is ROBOFORTH II which makes this robot really easy to get started with yet capable of the most complex tasks, assisted by RobWin project manager which brings everything together on one Windows screen.


Drives:High power micro-stepped hybrid stepping motors,
optional encoder watchdogs
Reach: 500mm/20ins in any direction; 360 degree waist rotation
Repeatability:0.2mm (see note)
Payload:nominal 400g, max 800g (2lbs) at flange
(repeatability and speed degrade with increasing payload and reach).
droop at 250mm at nominal payload:
droop at max reach with max payload:

Maximum speed: Shoulder 180 deg/sec, Elbow 270deg/sec, Waist 180 deg/sec.
Standard cycle time: 2 secs.
Max torque for hand pitch or yaw:2 Nm (repeatability figures degrade).
Max torque for 6th axis roll:0.25 Nm (repeatability figures degrade).
WeightRobot 13.0Kg/29lbs Controller 11kg/25lbs
Power: 110/240v ac 420VA (standard controller)
Temperature range:0 - 30C (wider range optional)
MTBF: 10,000 hours
Safety:Class 2 stop circuit, stall detect, risk assessment guide.
High intensity LEDs along the arm serve as awareness barrier.
Noise:Approx 40-50dB at 1m.
note: repeatability measured as a standard deviation of all 3 dimensions at 100% speed and zero payload over 24 hours after a 1 hour
warming up period. Figures for ISO 9283 available on request.


(click the thumbnail to view)
Six axis demonstration
non-youtube flash
Moving glass tubes
non-youtube mp4
chess pick and place
more videos



The role of the encoders in the R17 and as an R12 level 1 option is as watchdogs. The loop is closed after completion of each individual motion which is not the same as servo control. The R12 encoder option comprises miniature optical incremental encoders fitted to each axis.
Without encoders the R12 will run accurately and indefinitely open loop without error thanks to micro-stepping drives and accurate transmission. But if the robot suffers a collision then the controller does not know and carries on with the program even though the robot could be out of position. Such collisions usually only occur accidentally during programming and rarely during normal running. It is necessary to run the calibrate routine after such a collision.
If the encoder option is not fitted ST provides a software solution in the form of a quick calibration check that can be included in every robot cycle or n cycles. If there is an error it is reported and the system stops. Note that the 6th axis itself does not have an encoder as the axis is too small and compact to fit one in. But this axis is wrist roll, very difficult to stall and can be individually recalibrated if necessary.

As standard the robot terminates in a mounting flange (see diagrams below). End effectors currently include: electric gripper, SMC 10mm pneumatic gripper, vacuum pickups.
Note: pneumatic gripper is shown with special fingers made for a particular application, not part of the option. Fingers to suit the clients product may be made by the client or ST.

Linear track
up to 3m length, using a powerful motor and two recirculating crossed roller bearings.

High resolution or high speed options.
see video


Arm comprises 2 limbs 250mm each plus 360 degrees base rotation.
Therefore the workspace is a sphere 1000mm (40ins) in diameter (not including the hand).
Base fixings to bench
Wrist flange (not to scale)

Warranty, Maintenance and Support

ST Robotics 2009-13