HERMIES-III is an autonomous robot comprised of a seven degree-of-freedom (DOF) manipulator designed for human scale tasks, a laser range finder, a sonar array, an omnidirectional wheel-driven chassis, multiple cameras, and a dual computer system containing a 16-node hypercube expandable to 128 nodes. The current experimental program involves performance of human-scale tasks (e.g., valve manipulation, use of tools), integration of a dexterous manipulator and platform motion in geometrically complex environments, and effective use of multiple cooperating robots (HERMIES-IIB and HERMIES-III). The environment in which the robots operate has been designed to include multiple valves, pipes, meters, obstacles on the floor, valves occluded from view, and multiple paths of differing navigation complexity. The ongoing research program supports the development of autonomous capability for HERMIES-IIB and III to perform complex navigation and manipulation under time constraints, while dealing with imprecise sensory information.

The global trajectory control of walking machines is addressed here with particular attention paid to the consequences of actuator redundancy for control and to the inclusion of actuator dynamics in trajectory controller design. Redundancy of actuation, typical of walking machines, results in the trajectory control problem being formulated perforce in a global coordinate frame, instead of the joint space, as in nonredundant manipulators. This lack of one-to-one correspondence between the degrees of freedom of motion in the global coordinate frame and the actuators results in coupling between the different trajectory control loops. A mechanism for reducing this coupling effect is proposed here, along with a procedure to take into account approximately the effect of actuator dynamics in designing the trajectory controllers. The proposed methods are evaluated by simulation for an example problem in legged locomotion and are shown to be effective.

When a free-ranging walking machine carries its own fuel and power source as well as a payload, it is important to maintain high mechanical efficiency. If the masses of the legs are negligible then, in a straight and level walk, the only power to be generated would be that needed to overcome ground and wind resistance and internal frictions. The paper shows this to be the case when one-input straight-line generating mechanisms are used. However, when two-input mechanisms are used the actuators can work against each other resulting in finite, sometimes large, power requirements. The paper determines the effects of limb lengths and ground clearance on step length and quantifies the power requirements of serial-operated and parallel-operated legs. It shows that parallel-operation offers greater efficiency.

A new type of an iterative learning control method is proposed for dynamic systems with uncertain parameters. The method, which employs the model algorithmic control concept in the iteration sequence, is shown to be convergent for linear time-varying systems. Then the method is shown to be applicable for continuous-path control of a robot manipulator.

Order-picking, i.e. arranging work-pieces of different types on a pallet, which is nowadays often carried out manually, will in future be more and more automated for economic reasons. The industrial robot in combination with an intelligent gripper, a supporting palletizing and order-picking software and a suitably designed periphery will permit fully automated order-picking. The Fraunhofer-Institute for Manufacturing Engineering and Automation (F.R.G.) has developed such a system which takes advantage of the arrangement of the work-pieces in the compartment stack and simultaneously grips the work-pieces that are then arranged in a pattern on a pallet.

A prototype robot system for automated handling of flexible electrical wires of variable length is described. The handling process involves the selection of a single wire from a tray of many, grasping the wire close to its end with a robot manipulator, and either placing the end in a crimping press or, for tinning applications, dipping the end in a bath of molten solder. This system relies exclusively on the use of vision to identify the position and orientation of the wires prior to their being grasped by the robot end-effector. Two distinct vision algorithms are presented. The first approach utilises binary imaging techniques and involves object segmentation by thresholding followed by thinning and image analysis. An alternative general-purpose approach, based on more robust grey-scale processing techniques, is also described. This approach relies in the analysis of object boundaries generated using a dynamic contour-following algorithm. A simple Robot Control Language (RCL) is described which facilitates robot control in a Cartesian frame of reference and object description using frames (homogeneous transformations). The integration of this language with the robot vision system is detailed, and, in particular, a camera model which compensates for both photometric distortion and manipulator inaccuracies is presented. The system has been implemented using conventional computer architectures; average sensing cycle times of two and six seconds have been achieved for the grey-scale and binary vision algorithms, respectively.

A new approach to redundant robots is presented. The problem of the multiple solutions of the inverse kinematic is solved by making a special distribution of robot external motions to the redundant number of joint motions. The distribution is made in such a way to separate the smooth transport motion from the relative motion which could be fast and have high acceleration.

A redundant robot manipulator has several certain or expected advantages over a nonredundant one. It is expected, among other capabilities, that the joints vary with constant velocities during the execution of those tasks which in a nonredundant manipulator require variable joint velocities. In this way, motion becomes more precise because of the elimination of errors associated with velocity change in joints. In this paper, it is shown that this expected advantage is not possible for all the joints, and that only as many joints as the degree of redundancy can have constant velocities.

The flexible structure of a robot multi-links manipulator can be either a side effect or, on the contrary, an essential feature. We present a fairly general model to derive the corresponding dynamic equations in quite a systematic and simple way. To this end, we use the Lagrange formulation with strain energy potential and Raleigh (dissipation) functions. The approach can incorporate torsional deformation and aerodynamic friction, and it applies easily to robots working in the sea. The trajectory control appears to be one in the presence of model imprecision, and a slightly modified version of the classical sliding control technique is utilized to design the tracking control of the manipulator. Then we introduce the time-varying inertia link device (carried out by means of sliding masses) which we suggested in earlier work, and we show how it can be used to improve the tracking control scheme above. This paper contributes new ideas concerning flexible multi-links arms and active inertia links.

Velocity similarity principle V(θ., ṡ, ub, Qb) = DabV (θ., ṡ, ua, Qa)D ab–1 is presented and used to derive several useful forms of the Jacobian matrix for the manipulator from its basic kinematic equations in 4 X 4 matrix form. The zero reference position representation is used and, therefore, the base system is the only coordinate system utilized in the derivations. For manipulators with a spherical wrist, a modified form of the Jacobian is presented in which the Jacobian columns corresponding to the regional structure are completely decoupled from those corresponding to the wrist structure.