The problem of using active touch (haptic) exploration to recognize a 3-D object taken from a known set of models is examined. Two approaches are combined: (1) the use of geometric constraints between components to eliminate interpretations and of interpretation-tree methods for choosing the best active sensing move; and (2) exploratory moves made by tracing continually along the surface of the object (and not through free space). The study is restricted to polyhedra, and a set of geometric constraints tailored for matching components acquired from haptic exploration against components in the models is given. A new constraint using pairs of line segments is presented. A set of active sensing moves, each with an associated cost measure, and strategies for choosing the next move are given.>

An algorithm is presented which, given a desired position and normal for each fingertip, computes all the joint angles for the fingers and arm. The primary method for handling this underconstrained problem is to optimize a cost function. Methods are also given for generating good candidates to be optimized. Several new techniques are given for using the quaternion form to optimize rotation. Experimental results from using the algorithm to apply complicated grasps with a Utah/MIT hand-arm system are presented.>

A system for programming and controlling a multisensor robotic hand (Utah-MIT Hand) is described. Using this system, a number of autonomous tasks that are easily programmed and include combinations of hand-arm actuation with force, position, and tactile sensing have been implemented. The system is controlled at the software level by a programming language DIAL that provides an easy method for expressing the parallel operation of robotic devices. It also provides a convenient way to implement task-level scripts that can then be bound to particular sensors, actuators, and methods for accomplishing a generic grasping or manipulation task. Experiments using the system to pick up and pour from a pitcher, unscrew a lightbulb, and explore planar surfaces are presented.>

The authors describe an integrated system for dextrous manipulation using a Utah-MIT hand that makes it possible to look at the higher levels of control in a number of grasping and manipulation tasks. The system consists of a number of low-level system primitives for integrated hand and robotic arm movement, tactile sensors mounted on the fingertips, sensing primitives to utilize joint position, tendon force and tactile array feedback, and a high-level programming environment that allows task level scripts to be created for grasping and manipulation tasks are described that have been implemented with this system.>

The use of a dextrous, multifingered hand for high-level object recognition tasks is considered. The paradigm is model-based recognition in which the objects are modeled and recovered as superquadratics, which are shown to have a number of important attributes that make them well suited for such a task. Experiments have been performed to recover the shape of objects using sparse contacts point data from the hand with promising results. The authors also propose an approach to using tactile data in conjunction with the dextrous hand to build a library of grasping and exploration primitives that can be used in recognizing and grasping more complex multipart objects.>

The author presents a representation for a line in Euclidean three-space which uses only four parameters (the minimum number possible). Unlike other four-parameter representations. it has no singularities and special cases. The representation readily generalizes to Euclidean n-space, where it uses 2n-2 parameters. Possible applications include data compression, handling sets of parallel lines, representing kinematic linkages, and optimization problems.>

The authors consider an object is undergoing rotational motions, with orientation known at given times, and wish to interpolate the orientation between those times. If the orientations are represented as unit quaternions, this is equivalent to interpolating among a sequence of points on the three-sphere in four-space. They present an algorithm for doing this smoothly. If the object possesses rotational symmetry, then its orientation is given by its axis, and can be represented as a point on the unit sphere in three-space. The problem of interpolating on the sphere is of interest in its own right, and has other applications. The authors have implemented an algorithm for this, and present graphical results.>