The speed and accuracy of the ABB IRB 360 FlexPicker robot is impressive, and the machine vision even more so.
Position repeatability is 0.1 mm!
The four-bar mechanism comprising the arms of the robot is innovative. Through a set of three motors and spherical joints at the shoulders and wrists, the ‘bot can move the end effector to anywhere within a sizable cylindrically-shaped working envelope. In my machine design class as an undergrad, we learned the theory which predicts the location of elements within a four-bar linkage system. I explicitly recall my prof saying, “Four-bar linkages are quite good for motion in-plane, but it’s quite difficult to get them to operate out-of plane.” The FlexPicker effectively gets three four-bar assemblies in different planes to function together through the use of spherical joints at the elbows and wrists and–from the looks of it–it’s capable of speeds that traditional X-Y translation or robot-arm setups just couldn’t do for pick-and-place operations. While single-plane four-bar linkage calculation is fairly straightforward–essentially geometry on steroids–I would be interested to see the control scheme used by ABB for the machine. A whole new set of challenges is introduced by those spherical joints.
The unique three-arm, four-bar design also obviates the need to place motors at the elbow or wrist joint, allowing the “humerus” and “forearm” linkages to be quite light. A traditional robot taking the form of a human arm requires heavy, torque-producing motors at those locations. Granted, a traditional robot arm can do much more complex work than the FlexPicker can.
Technical datasheet for the ABB IRB 360.