A high-level controller for a SMALL workcell (Sawyer-motor assembly workcell) is presented. It allows multiple independent process to share the robot modules and workspace of a single workcell, by planning and scheduling collision-free paths for module motions in real time. Planning may involve moving around other modules, stationary or in motion, waiting for motions to complete, or displacing obstructing idle modules. The controller handles any number of robots in simultaneous motion along paths consisting of multiple rectilinear segments. Collision avoidance and path-planning are addressed in two dimensions, with extensions to three dimensions briefly discussed. Design considerations for the algorithms involve throughput, protection, fairness, and starvation considerations. Capabilities to allow independent processes to cooperate without interference are provided.>

The FLAIR (flexible assembly intelligent robot) workcell loads odd-shaped through-hole and surface-mount components onto printed circuit boards. It is 100% data driven, handles diverse components and boards in arbitrary batch sizes, uses computer vision for viewing components and boards, and incorporates sensor-based error detection and recovery, generic parts feeders, general purpose lead straightening, and lead clinching. It automatically calibrates cameras and robot. FLAIR functions either stand alone or are integrated into an assembly line.>

Currently, a major difficulty for the widespread use of robots in assembly and material handling comes from the necessity of feeding accurately positioned workpieces to robots. ``Bin picking'' techniques help reduce this constraint. This paper presents the application of matched filters for enabling robots with vision to acquire workpieces randomly stored in bins. This approach complements heuristic methods already reported. The concept of matched filter is an old one. Here, however, it is redefined to take into account robot end-effector features, in terms of geometry and mechanics. In particular, the proposed filters match local workpiece structures where the robot end-effector is likely to grasp successfully and hold workpieces. The local nature of the holdsites is very important as computation costs are shown to vary with the fifth power of structure size. In addition, the proposed filters tend to have a narrow angular bandwidth. An example, which features a parallel-jaw hand is developed in detail, using both statistical and Fourier models. Both approaches concur in requiring a very small number of filters (typically four), even if a good orientation accuracy is expected (two degrees). Success rates of about 90 percent in three or fewer attempts have been experimentally obtained on a system which includes a small minicomputer, a 128 × 128 pixel solidstate camera, a prototype Cartesian robot, and a ``universal'' parallel-jaw hand.

The feasibility of robots employing vision to acquire randomly oriented cylinders has been demonstrated for the first time. An experimental robot system using vision and a parallel jaw gripper was able to acquire randomly oriented cylindrical workpieces piled in bins. Binary image analysis was adequate to guide the gripper into the multilayered, piles. Complementary information was provided by simple sensors on the gripper. Experiments were performed using titanium cylinders 6 cm × 15 cm diameter and 7.6 cm × 3 cm diameter. Cycle times to acquire a cylinder and deliver it to a receiving chute ranged from 8 to 10 s when a single supply of one-size cylinders was used. By using a dual supply bin configuration with one bin of each size and overlapping arm motion and image analysis tasks, the cycle times for one cylinder from alternate bins ranged from 5.5 to 7.5 s per piece. In the future robots with such capabilities can be applied to enhance automation applications, especially in small batch production.

A robot system has been tested which can acquire a class of workpieces that are unoriented in bins and transport them, one at a time, to a destination with the proper orientation. This kind of robot has numerous applications in industries which manufacture discrete-part products in batches. A variety of approaches to the design of an orienting robot have been identified. For acquisition, gripper design and vision algorithms should be considered together. A vacuum gripper which adapts to surface angle and an algorithm which finds the center of smooth regions in the bin image have been shown to form an effective combination. Knowledge of the position and orientation of the workpieces near the top of the bin is not necessary for acquisition. Collisions with workpieces in the bin whose poses are not known can be avoided by having the gripper follow a line of sight approach path. To simplify the computation of workpiece orientation, it was found to be useful to employ a gripper which locked a workpiece in one of a finite number of states and which did not obscure the workpiece. For an orienting robot which is designed to service a variety of different workpieces, using an arm with six degrees of freedom greatly facilitates workpiece transportation.