Requirements regarding a robot’s speed, accuracy and weight have led to novel kinematic and transmis- sion designs。 An approach toward lightweight and stiff structures has been pursued since the 1980s by develop- ing parallel kinematic machines (PKM) which connect the machine’s basis with its end-effector by three to six parallel struts, see also Fig。 54。5。 These so-called par- allel robots (Chap。 4 and 18) are particularly suited to achieve short cycle times (e。g。, for picking), precision (e。g。, for material removal), or handling high workloads (Fig。 54。5) and have found their niches in advanced manufacturing [54。14]。 However, workspace volumes tend to be significantly smaller than those of serial or open kinematic chain robots which are comparable in size。

Efforts of reducing mass and inertia of serial robot structures have been a primary research target, where the human arm with  a  weight-to-load  ratio  better than 1 W 1 was considered the ultimate benchmark。 In 2006, robot manufacturer KUKA introduced their LBR lightweight prototype robot, a compact 7-DOF robot arm with advanced torque-control capabilities which has recently been introduced in high-performance in- dustrial applications [54。15]。 An obvious next step in approaching human dexterity is the recent introduc- tion of two-armed robot designs with some recent developments being depicted in Fig。 54。7 [54。16]。 In conjunction with a robot’s capability to support safe human–robot collaboration, new manufacturing con- cepts can be implemented which expand capabilities, productivity, and ergonomic quality to manual work- places [54。17]。

Fig。 54。4 An automated video cassette recorder (VCR) assembly line (about 1989)  with SCARAs carrying  a  turret with multigripper tools。 Typically five parts are added by one robot before the VCR is moved to the next station of the automated assembly line

Fig。54。5a–c  Parallel robots are slowly diffusing into various fields of industrial application: (a) the Neos Tricept 600,

(b) Fanuc F-200iB。 (c) Adept Quattro。 (a) In 1992, Neos Robotics represented with their Tricept robot range a concept to combine the stiffness of machine tools with the dexterity of a robot for heavy-duty applications such as in friction stir welding (FSW) or machining of aluminum for the aircraft industry。 (b) The Fanuc F-200iB introduced in 2002 is a 6-DOF parallel robot particularly designed for welding gun handling, deflashing, or for assembly tasks (100 kg payload,

˙0:1 mm accuracy) in automotive assembly processes; (c) the Adept Quattro (introduced in 2007, following the ABB FlexPicker in 1998) is suited for high-speed applications in packaging, manufacturing, assembly, and material handling。 The quad dual-link arm design forms an over-determined kinematic linkage, which in the wrist is converted to the forth axis of end-effector rotation by means of an internal transmission in the wrist

In parallel to industrial robots, automated guided vehicles (AGV) have emerged。 These  mobile robots are used for moving workpieces or loading  equip- ment following a predetermined or virtual path in industrial environments。 Within the concept of auto- mated flexible manufacturing systems (FMS) AGVs have become an important part of their routing flex- ibility。  Initially, AGVs  relied  on prepared  floors such

as embedded wires, magnets, or other  tags  for mo- tion guidance。 Meanwhile, freely navigating AGVs along virtual trajectories are entering large-scale man- ufacturing and logistics。 Usually, their navigation is based on laser scanners that provide an accurate two- or even three-dimensional map of the actual environ- ment for self-localization and obstacle avoidance。 Early on, combinations of AGVs  and robot arms were   sug-