In his Bachelor Thesis, Markus Behrens did several measurements about repeatabilty and absolute precision of one igus Standard Joint arm (5 DOF, big Version): RL-D-RBT-5532S-BC-AE.
A CPR (Commonplace Robotics) control unit was used for the evaluation. The main results and further details are given in the pdf document attached. Conclusion:
igus supplies “electromechanical joint arms“. They consist of:
- robolink joints with worm gears (RL-D) and strain wave gears (RL-S),
- igus stepper motors NEMA11, -17, -23 and -23XL,
- Ini-switches for the Zero-Point definition (BC version) or Output encoders (BC-AE version),
- connection parts between these joints (folded metal sheets RL-DC)
- a set of igus cables (5m long) and e-chains for the connection to a control unit
- OPTIONAL: an adapter for the connection of an Actuator (gripper, suction cup, camera,…)
Please find attached data sheets and STEP data for the different configurations:
“small version” with 2x RL-D-30 and 2x RL-D-20 (payload max. 1 kg, reach ~600 mm)
“big version” with 2x RL-D-50 1x RL-D-30 and 1x RL-D-20 (payload max. 3 kg, reach ~750 mm)
We supply 2 options of encoders for our joints / joint arms.
Option 1 (our Standard before HMI 2017): Motorencoder plus Ini switch for 0-point reference on the joint output (PRT bearing)
Option 2): Output encoder on the PRT bearing of the joint. This is our own development, we use a magnetic ring plus Encoderchip on the output with an aditional magnet and Hall Sensor as reference point. Please find attached a description of the output encoder attached in GER and ENGL. Advantage: less cables, higher resolution, more accuracy for the arm.
The strain wave gear is available as a product in the size RL-S-17 and RL-S-20. RL-S-30 is a prototype and still in development.
The cyclo gear can be an alternative in future and is not available as a product yet. The sizes 17 and 20 are currently in development.
Both types of gears contain a coaxial in- and output axis (different from RL-D worm gears), they consist of three similar components:
- An outer (static) toothed ring
An inner toothed ring (rigid in the cycloid gear, flexible in the SWG)
A drive (an excentric in the case of the cycloid gear, the wave generator in the SWG)
strain wave gear with flexible inner ring cycloid gear with excentric ring
I want to supply more data for you to be downloaded, especially about our RL-DC “standard arms”. Our standard arms include all joints, motors, connections (=c-shaped metal sheets), cables and chains. Attached our NEW catalogue (now also available in ENG), STEP data for our 8 standard configurations and also the related drawings with part lists. We have “small arms” (up to 1 kg, based on our joints RL-D-30 and RL-D-20) as 4 or 5 DOF and “big arms” (up to 3 kg, based on our joints RL-D-50, -30 and -20).
Version With motorencoder and Ini switch or “output encoders” (-AE). I will explain the difference in a later entry.