Chihiro Sawada

Open controller architecture OSEC-II: architecture overview and prototype systems

The Open System Environment (OSE) consortium, which consists of 18 major companies and a public research institute in Japan from various industries as of February 1997, has been organized to establish, demonstrate, and standardize an open architecture for easy implementation of high-value-add functions based on information technology in controllers of factory automation (FA) machines. This paper gives an overview of the OSEC-II (Open System Environment for Controllers, Version 2) architecture released by the consortium in August 1996, and reports on some prototype systems based on the architecture.

Stable compliance control and its implementation for a 6 DOF manipulator

The authors propose and analyze a method for position-based compliance control with position gain control. It is shown that, for a stiff manipulator, the stable regions of desired compliance are extended by adjusting the internal position feedback gain to a level suitable to the desired compliance. The stable regions in an infinitely stiff environment for various position feedback gains are also described. This position-gain control method was implemented in a compliance-controller consisting of a few microprocessors and a 2-MFLOPS (million floating-point operations per second) floating-point processor. It can control the compliance of an industrial manipulator with six degrees of freedom at a frequency of 500 Hz. As a result of an experiment in which the manipulator under the compliance control was in contact with an infinitely stiff object, it was confirmed that the motion of the manipulator was stable when the compliance parameters were within the theoretically stable region.<<ETX>>

Evaluating the performance of robotic compliant tasks according to power consumption: approach and applications

This paper proposes an approach to the quantitative evaluation of the performance of robotic compliant motion tasks based on the power consumed by interaction between parts. As an application of the technique, a method for tuning the compliant motion parameters is discussed. It employs the response surface method as a schema for experimental design, because of the methods similarity to the process whereby humans tune parameters. Finally, to confirm the effectiveness of the tuning method, it is applied to a socket attachment task.

Specification and generation of a motion path for compliant motion

To represent compliant motion, the authors present a theory for specifying and generating the motion path of a robot in contact with the environment. Included is a formulation for specifying single contact motion, in which only one geometric feature (a vertex, an edge, or a plant) or a robot and one geometric feature of the environment participate. Single contact motion is categorized into four types according to the combinations of the movabilities of the contact positions on the robot and the environment. For each type of single contact motion, an interpolating transformation is assigned to generate motion from the path specification. In addition, motion constraints are provided according to combinations of geometric features. A geometric model of the task environment allows the formulation to be applied to automatic path generation in programming motion segments.<<ETX>>