Advanced Robotics

Igarashi, Eturoo; Nogai, Tooru

doi: 10.1163/156855392X00097pmid: N/A

In biped locomotion, there are a double supporting phase with a kick and a single supporting phase concerned with making a forward step. This study is concerned with dynamic analysis and control in the double supporting phase. This phase is a closed-loop link system (constraint dynamic system) in which the dynamic states (floor reaction, joint torque) are restricted because the feet are not fixed to the floor. Therefore, it is preferable to use an analytical method by which the dynamic states would become clear. In this respect, the paper first refers to an analytical method using D'Alembert's principle, in which static forces are derived from static equilibrium equations for each link. Then, based on the analytical result, a control experiment is carried out and the usefulness of this method is shown.

Beiner, L.

doi: 10.1163/156855392X00105pmid: N/A

This paper presents an engineering approach to the time optimization of robotic motions with specified paths and trapezoidal velocity profiles. Optimizations of this type occur when dealing with continuous-path motions of commercial manipulators. Parameterized path equations and full non-linear robot dynamics are used in conjunction with the actuator limitations and the specified path and velocity profile in order to transform the problem into a non-linear programming form. The optimal velocity profile and the corresponding joint torques/forces are obtained via a simple search algorithm, without resorting to any constrained optimization technique, numerical integration, or search for the switching curve. Three examples of time-optimized robotic motions are presented.

Hong, Hyung-Joo; Yoon, Yong-San

doi: 10.1163/156855392X00114pmid: N/A

In this study, a numerical procedure for designing kinematic parameters of SCARA-type manipulators is proposed to yield such a design that the resulting manipulator has the fastest cycle time for a given task. To achieve this goal, an optimization problem is formulated to minimize the cycle time by determining geometric parameters such as the link lengths and the locations of manipulators as well as the trajectory. The representative task to get the cycle time is defined as CP (continuous path) motion along the path crisscrossing the standard working area. A gradient projection algorithm is used to obtain the optimal design with the assumption that each actuator should exert a torque and angular velocity within the capacity of specific commercially available direct-drive motors. SCARA-type manipulators of both absolute coordinate and relative coordinate types are designed to reduce the cycle times. The results show that the absolute coordinate manipulator produces a shorter cycle time than the relative coordinate manipulator in optimal designs.

Schwinn, W.

doi: 10.1163/156855392X00123pmid: N/A

This paper describes a new algorithm for analysing the influence of the tool geometry on the motions of industrial robots in large manufacturing systems. On the basis of given points which are defined by the periphery devices used, the proposed method allows an evaluation of the cycle time. The computational time which is needed to determine the robot trajectory is kept small because an approach with constant velocities is calculated instead of the real path. In addition to an analysis of a single motion between two points, it is possible to calculate values for motions between several points which are linked together by a point to point move, so that an optimization of complex processes can be reached.

Ishikawa, Masatoshi

doi: 10.1163/156855392X00132pmid: N/A

The state of the art of sensor fusion and problems to be solved are described. The basic concept of sensor fusion is classified in contrast to the function of the brain and problems of sensor fusion are defined from the viewpoints of hardware, software, and algorithms such as signal processing, artificial intelligence, and neural networks. A new concept and an architecture for active sensor fusion are described. Development of the sensor fusion architecture is difficult and many problems remain to be solved in the future.

Akiyama, Terunobu; Shono, Katsufusa

doi: 10.1163/156855392X00141pmid: N/A

This paper describes an experimental study of the fabrication of micro-mechanisms on a silicon wafer. Planar process technology developed in the industry of CMOS LSI was employed. The structural material is CVD-polycrystalline silicon with a thickness of 2.5 μm and the sacrificial material is CVD-SiO2 with a thickness of 1.0 μm. In the experimental study, micro-rotors with a shaft and a cap in an assembled form were fabricated on a silicon wafer. The self-alignment process gave a tolerance of 1.0 μm between the rotor and the shaft. The maximum rotation speed observed was 9 x 104 rpm by blowing nitrogen gas.

Higuchi, Toshiro; Yamagata, Yutaka

doi: 10.1163/156855392X00150pmid: N/A

A unique precise positioning mechanism is introduced. It utilizes inertial force and friction, and can make step-like motion of several nanometres up to several micrometres. Repeating step-like movements, precise positioning with a resolution of several nonometres and for an unlimited movable range is possible. Prototypes of joint mechanisms for a micro robot and a 4-degrees of freedom micro robot arm were constructed using this mechanism. These arms and joints proved to have a high positioning resolution and a practical maximum velocity. Applications of this micro robot arm are also discussed.

Tashiro, Hirofumi

doi: 10.1163/156855392X00169pmid: N/A

Iguchi, Nobuhiro; Fujishiro, Tomoko

doi: 10.1163/156855392X00178pmid: N/A

Iguchi, Nobuhiro; Hirose, Kooichi

doi: 10.1163/156855392X00187pmid: N/A