Fumio Ozaki

Virtual robot experimentation platform V-REP: a versatile 3D robot simulator

From exploring planets to cleaning homes, the reach and versatility of robotics is vast. The integration of actuation, sensing and control makes robotics systems powerful, but complicates their simulation. This paper introduces a modular and decentralized architecture for robotics simulation. In contrast to centralized approaches, this balances functionality, provides more diversity, and simplifies connectivity between (independent) calculation modules. As the Virtual Robot Experimentation Platform (V-REP) demonstrates, this gives a smallfootprint 3D robot simulator that concurrently simulates control, actuation, sensing and monitoring. Its distributed and modular approach are ideal for complex scenarios in which a diversity of sensors and actuators operate asynchronously with various rates and characteristics. This allows for versatile prototyping applications including systems verification, safety/remote monitoring, rapid algorithm development, and factory automation simulation.

Adaptive model-based hybrid control of geometrically constrained robot arms

This paper reports comparative experiments with a new model-based adaptive force control algorithm for robot arms. This controller provides simultaneous position and force trajectory tracking of a robot arm whose tool tip is in point contact with a smooth rigid surface. The algorithm is provably stable with respect to the commonly accepted rigid-body nonlinear dynamical model for robot arms. Comparative experiments show the new adaptive model-based controller to provide performance superior to that of both nonmodel-based controllers and nonadaptive controllers over a wide range of operating conditions.

Development of a concept model of a robotic information home appliance, ApriAlpha

We have proposed a concept of a robotic information home appliance corresponding to one category of home robots, and developed ApriAlpha, a concept model of the robotic information home appliance. ApriAlpha is a wheel locomotion type human friendly home robot which controls advanced home appliances, standing between their users and them as a voice controlled information terminal, and offers security and information services to users. We have integrated various robot technologies such as voice communication, image recognition, planning and motion control on ApriAlpha, and we have introduced a framework of the distributed object technology based open robot controller architecture (ORCA), which we are currently developing in view of its easy extension and efficient development. This paper describes the proposed robotic information home appliance and its concept model, ApriAlpha. The functions of the developed robot are confirmed by performing several demonstrations, and the merit of applying the framework of ORCA to the home robot controller is also confirmed through its development.

Development of a force controlled robot for grinding, chamfering and polishing

This paper presents a force controlled robot system for grinding, chamfering and polishing in machining plants. To facilitate easy operations, a task-oriented robot language and a force control method for following the edges of workpieces have been developed. In the task-oriented robot language, a task is declared first by a task name, a tool code and a tool center point. The tool center point is a position in contact with a workpiece. These indexes and the force control motion command determine the parameters for the force control of the robot. The workpieces for grinding, chamfering, and polishing almost always differ their setting positions, their sizes and/or their shapes, even when the workpieces are the same parts in a machine. To cope with the workpiece difference, a tool moment control method, a skip function, and a round function have been developed. Experiments on chamfering of the edges of a part in an injection molding machine are reported.

Development Of A Pingpong Robot System Using 7 Degrees Of Freedom Direct Drive Arm

A pingpong robot system using a 7 degrees of freedom direct drive arm has been developed. This system is composed of a binocular camera for measuring the position and the speed of a pingpong ball, a pitching machine, a direct drive robot, and a controller with a multi-microcomputer system. Three important techniques have been developed here. First involves the fast ball position measurement technique using the binocular camera, which has two linear sensors located horizontally on the focal plane of each lens. Second is a technique for forecasting hitting position and time. Third, direct drive robot control technique with real time calculation of inverse kinematics. These techniques are essential to perform unstructured tasks with a robot in real time.

A volleyball playing robot

We developed a robot system which can play one-on-one volleyball games with a human player. It can not only hit a flying ball back to the player correctly but also have various autonomous functionalities to interact with humans necessary for playing games, i.e., it can pick up a ball of a requested color by recognizing voice instructions, can locate the players by recognizing their faces, and can shake hands. This robot performed the entire game sequence over 100 times at a company-sponsored exhibition, where the ball rally continued over 25 times with an arbitrary player. In this paper, we mainly describe the real-time visual feedback system of the robot which is essential for playing ball games.

A collaborative multi-site teleoperation over an ISDN

Abstract We have developed an advanced infrastructure and technologies for collaborative remote operations, enabling multiple operators with large physical separation to control multiple slave robots in a common environment over the network. Human operators’ delayed visual perception arising from communication time delays seriously affects the performance of collaborative multi-site operations and accordingly requires supplementary information locally available to operators irrespective of time delays. Few facilities exist to investigate remote multi-site operations, thus we have built an experimental test bed connecting Tsukuba and Kawasaki in Japan via an integrated services digital network. In particular, an on-line predictive graphics simulator is incorporated to cope with image feedback delays from the remote site. Specifically, exploiting audio-visual features of the simulator, operators can detect a priori the possibility of collision between robots and guide them towards task goal through time delays. To verify the validity of the simulator assisted approach, we have performed a demonstration of prototype plant maintenance in April 2000 between Tsukuba and Kawasaki.

Dynagent: an incremental forward-chaining HTN planning agent in dynamic domains

HTN planning, especially forward-chaining HTN planning, is becoming important in the areas of agents and robotics, which have to deal with the dynamically changing world. Therefore, replanning in “forward-chaining” HTN planning has become an important subject for future study. This paper presents the new agent algorithm that integrates forward-chaining HTN planning, execution, belief updates, and plan modifications. Also, through combination with an A*-like heuristic search strategy, we show that our agent algorithm is effective for the replanning problem of museum tour guide robots, which is similar to the replanning problem of a traveling salesman.

Robot control strategy for in-orbit assembly of a micro satellite

We have developed novel heuristic control strategies for fitting parts with almost no clearance and also dealing with flexible objects using visual and force feedback. We have applied these control strategies for micro satellite assembly tasks of a ground research model of an in-orbit maintenance robot system. For the in-orbit maintenance system, micro satellites should be modularized as much as possible. The in-orbit maintenance system needs to assemble the modularized parts into micro satellites. We have developed a ground research model including a two-armed robotic platform and modularized micro satellite models. To assemble a micro satellite model, two problems arise: one is to engage two parts into a tight fit and the other is to handle flexible parts. We use a heuristic approach to solve the first problem — to grope one part to find the entrance of engagement of the other and to wobble this part to make a tight fit. For the second problem, visual measurement of the parts is used to position the end-effector of a robot arm and also active limp control is extensively used to adjust any misalignment that arises from the visual measurement error. With the combination of the heuristic, visual and active limp control, the system can successfully assemble a micro satellite.

Experiments in adaptive model-based force control

This paper reports comparative experiments with a provably correct model-based adaptive robot control algorithm for simultaneous position and force trajectory tracking of a robot arm whose gripper is in point contact with a smooth surface. The experiments show the new adaptive model-based offers performance superior to that of its non-model-based counterpart over a wide variety of operating conditions.