This paper presents the conceptual designs, kinematics and dynamics modeling of a cooperative re-configurable Dual-Arm Cam-Lock Manipulator. A cam-lock manipulator is a robotics structure with a pair of multi-degree of freedom planar arms jointed together at a shared base. This manipulator is designed to be capable of performing a wide variety of tasks by automatically re-configuring itself to form a variable geometry, stiffness, damping, and workspace robotics structure by the virtue of a novel link/joint design along i''s arms, labeled as the cam-lock design. The kinematics and dynamics of this manipulator is described using admissible variables (i.e., variables that define the constrained admissible motion). Along with the dynamic relations of this manipulator, a generic equation was also developed for the joint servo system.

In the computational kinematics of robotic manipulators, accuracy and sensitivity of the results are highly dependent on the choice of the coordinate system, the metric system, and the appropriateness of performance evaluation measure. In this paper, these undesired sensitivities are examined and suitable performance criteria are developed to eliminate the coordinate system and metric system dependencies, and adverse numerical effects associated with them. Also a new formulation for the Jacobian matrix, joint velocities, and hand velocities, based on the Euler angles, is developed. This formulation, further improves numerical accuracy of the computations. Numerical experiments are included.

This paper presents a linearization by static feedbacks in the robotic field, i.e. by feedback depending on the whole state space. A phenomenological approach is considered, which by using the derivation with respect to time, leads to the major results of the method. Simulation results are presented, and some aspects of the correction of the effect of the characteristic numbers are also discussed.

This paper describes the research activities at the Laboratory for Control Systems and Automation (LCA) which is a section of the Production Department of Korea Advanced Institute of Science and Technology (KAIST). LCA's research activities are focused on providing fundamental technologies to cope with the current trends in manufacturing automation. The R & D activities at the laboratory cover diverse areas. The research activities at the laboratory are classified into three sections—robotics and automation, fluid servo control, and manufacturing process control. Detailed explanations are given here on robotics and its application to automation. As a laboratory belonging to a nation's leading educational institution, LCA also conducts active educational activities. Such educational programs are also introduced in detail.

This paper present a nonlinear, model-based control of flexible link robots. The control task is formulated requiring rigid joints variables to track reference time-varying trajectory and elastic deflection to be damped. The stability and robustness properties of the control scheme are analyzed from a passive energy consideration. A direct adaptive version is also proposed. Extensive evaluation of this approach is performed using experimental validations involving a single-flexible-link and a two-flexible-link horizontal robot. Experimental results show significant performances of the controller under relatively severe working conditions: 700% payload to arm ratio and 20% elastic deflection ratio at highest acceleration stages.

This paper addresses the conceptual design of direct-drive manipulators which have good promise for high speed, high precision manipulation. In the design methodology presented, the procedure begins by considering the kinematic aspects and ends by configuring manipulator structures with promising kinematic and dynamic characteristics. Based on the conceptual design considerations, a novel 3 DOF (RRR) direct-drive manipulator is proposed and analyzed. The manipulator structure has only five links and a compact configuration. Manipulator kinematics and dynamics are analyzed. Design guidelines are derived for static balancing of the manipulator and for minimizing the inertias driven by the motors. Operational configurations that either improve or worsen the kinematic and dynamic behaviour or characteristics of the manipulator are identified. The proposed design has an advantage over many currently known direct-drive manipulators for achieving two desirable mechanical features, namely: static balancing and compactness (smaller driven inertias).

Many of the evolving technologies related to machining will expand the traditional concept of the machine tool industry. Preprocessing of materials into net or near-net shapes will reduce or even eliminate the need for machining operations. Conversion of particles into parts is one generic approach which, when automated, could be integrated into a machining center. Similarly diecasting or squeeze casting could become an integrated part of the machining center for volume production. The machine tool industry could automate die manufacturing so that dies could be made in real time and could justify net shape production for small quantities and rush jobs.

Much and often most of the time and costs within a “machining” operation are generated by secondary operations such as heat treating, plating, and welding–operations done in different parts of or even at different plants. The concept of extending the machining center to include these secondary operations has been considered for several years and to a limited extent, has occurred. Laser extended machining centers provide one possibility for integrating several of the secondary operations with machines at a single site.

Post processing of machined parts at the site of the machining center can result in parts oriented and appropriately presented or packaged for subsequent operations. When several machined parts subsequently become an assembly or subassembly, the concept of machining could be extended to include the assembly.

When machining is considered in this broader context, the technology futures of the machine tool industry are considerably broadened. Smarter machine tools, improved support structures, and high speed machining are important, but competitors are looking at the same opportunities and the competitive advantage is likely to be limited. “Leap frog” improvement depends on some of the less conventional technologies considered in this paper. Broadening of the machine tool horizons is likely to offer the technology path for revitalization and growth of the machine tool industry.

This paper is addressed at the difficulty of accurately modelling a two-flexible-link manipulator system, which is a necessary pre-requisite for future work developing a high-performance controller for such manipulators. Recent work concerned with the development of an accurate single-flexible-link model is first reviewed and then the expansion of a single-link model into a two-flexible-link system in a way which properly takes into account the coupling and interactions between the two links is discussed. The method of approach taken is to calculate the elastic and rigid motions of the links separately and then to combine these according to the principle of superposition. The application of the model developed is demonstrated in a simulated two-flexiblelink system.

An approach for collision–free trajectory planning along designated paths of two robots in a common workspace is presented. Specifically, in order to describe potential collision between the links of two robots along the designated paths, explicit forms of virtual obstacle are adopted, according to which links of one robot are made to grow while the other robot is forced to shrink as a point on the path. Then, a notion of virtual coordination space is introduced to visualize all the collision–free coordinations of two trajectories. Assuming that a collision–free coordination curve between the two robots is given via a virtual coordination space, the minimum time collision–free trajectory pair for the two robots is sought considering dynamic constraints of torque and velocity bounds of actuators of the two robots.

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.

It is shown that if one comes back to the formulation of the Hamilton's variational principle, it is then possible to obtain new viewpoints on the tracking control of robot manipulators. First, the Lagrange multiplier associated to the sliding surface can be interpretated in terms of control effort and/or forces of reaction of the mechanical system. Secondly, one can use the Taylor expansion of the mechanical Lagrangian, combined with a neighbour- ing Hamilton's principle, to obtain control schemes via sliding surfaces. Thirdly, a perturbation approach combined with the neighbouring Hamilton's principle provides results on the robustness of the control.

Traditionally, tactile sensors have been designed using compliant, rubber-like materials; when such a sensitized gripper grasps or otherwise manipulates an object, the normal strain deformation in the compliant material is sampled. The resulting information can be used to deduce simple local geometry of the contact, but the transduction process does not typically permit use of the individual strains in determining large-scale properties of the object (e.g., the inertia). Measurements of inertial parameters of grasped objects require accurate, low-hysteresis transduction that few tactile sensors currently provide.

An alternative is to work from the task specification, and determine the tactile information that is necessary to accomplish the task. Here, we consider how to sense the length and mass of a uniform object that is gripped in a gravitational field, and show the design and assessment of a new kind of tactile sensor that is based on the theory of the deformation of thin plates. Features of this design include its potentially rugged realization, and its high-accuracy measurement that is more typical of force sensors than of tactile sensors.