There are many robots which are controlled with PCs (Personal Computers) . Their typical OS (Operating System) was MS-DOS, but MS-DOS is not suitable for high level control. Therefore, RTLinux was developed as realtime OS. However, the authors tried to control mechatronic system by using common Linux and found that it has enough ability to control robots. In this paper, it is described why the common Linux can be used as OS for PCs that control robots. Some experimental results that indicate performance of common Linux as robot controlling OS are also provided. Then the control system developed for human type biped robot as an example that utilize this method is shown.

View full abstract

This paper discusses the manipulation of an object under equilibrium where the object makes rolling contact with the plate attached at the tip of the arm. We assume that the object satisfies the neighborhood equilibrium [1], where an object with rolling contact can automatically find another equilibrium state close to the original one even when the current one is broken due to the change of input. For always guaranteeing the neighborhood equilibrium, we newly define the contact stable region on the object surface. By utilizing the contact stable region, we propose a control scheme for manipulating an object from one to the desired position on a plate whose posture is controllable. Numerical example is also shown to explain our idea.

View full abstract

We have developed a new type of mobile robot system, in which robot executes a task under human assistance, aiming to improve reliability and rapidity of task performance. This robot system incorporates the human assistance for solving the unexpected problem arose during the task execution. The basic idea of the system is that in normal situation robot takes an autonomous action derected by the program, while in abnormal situation which means that some unexpected problem arose, human assists to help the robot action. As a system component, we have developed navigation command interpreter with intervention function to realize human assisted navigation conveniently. In this system, human assistance is also effectively utilized in the image information extraction for positioning error correction. We have demonstrated the feasibility of the system under the mock-up environment.

View full abstract

In this paper, human perception ability for robot impedance is analyzed. First, a human-robot system is con-structed using impedance control, where a subject can move the robot freely by his end-point, and two kinds of experiments are performed: single impedance perception and single impedance discrimination. Then, from the experimental results, the accuracy and the differential limen are discussed. Also, it is shown that the human perception ability decreases dramatically under some situations such as multiple impeadace perception and large robot viscosity. The results of the present paper could be effective as basic data in presenting the robot impedance to human operators in the rehabilitation system and human-robot systems.

View full abstract

Recently, omnidirectional mobile robots with holonomic property have been studied actively. We have already developed a holonomic and omnidirectional mobile robot which consists of two active dual-wheel caster assemblies and also derived the kinematic models for the assembly and the mobile robot. In this paper, we further derive a dynamic model for the mobile robot by using the forces acting on the steering axis and construct a resolved acceleration control system based on the model to realize a dynamic control for the mobile robot. An experiment using a prototype robot is performed to prove the validity of the model and the effectiveness of the control system.

View full abstract

A 3 degree-of-freedom micro finger, that has pure translational motion, is proposed. The finger will be applied in the two finger micro manipulation in order to manipulate micrometer size objects dexterously. The possible configurations are considered based on the group theory. Then, the optimal configuration is proposed by taking simple machining of joint structures into account. A kinematics analysis is made in order to describe the relation between end effector and actuator displacements. The design parameters are examined by evaluating the force capability of the actuator and the work space volume. Basic experiments are made by a prototype finger module that show excellent micro motion capability. A smaller hand mechanism is preferable in order to keep high accuracy, even through temperature and humidity change. Then a small-sized finger module is designed based on the prototype. A photo forming system is used for fabrication of the small-sized finger module. High accuracy is confirmed in the new finger module.

View full abstract

With the increase in the number of senior citizens, there is a growing demand for human-friendly wheelchairs as mobility aids. One of the main issues in the robotic wheelchair research is autonomous obstacle avoidance for safety. However, this is difficult because most of moving obstacles in the real world are human beings. They sometimes change their motion abruptly. This paper presents an intelligent wheelchair that can avoid collision with such human pedestrians safely and comfortably for each other. We assume that the information whether or not a pedestrian has noticed the wheelchair and which direction he/she wants to go can appear in the face direction. Thus our intelligent wheelchair is continuously observing the pedestrian's face in its front area, realizing smooth passing by changing its collision avoidance strategy based on the face information and the range data from the ultrasonic sensors. Experimental results show the effectiveness and comfortableness of the proposed method.

View full abstract

We are researching design and control of jumping robots (e.g. normal jump, somersault, jump on a stair) composed of a multi degrees of freedom link. We call such robots“Multi-DOF Jumping Robot”. In this paper, we deal with 5 link 4 joint serial link as an example of Multi-DOF Jumping Robot, and discuss about the way of determination of design parameters under realistic conditions. The design parameters mean not only mechanical parameters but also motion planning parameters. At first, we show the type of jumping motion that we deal with in this paper, and derive conditions to achieve that. Then, we propose a motion planning method for jumping motions on the basis of boundary state between ground and aerial phase. Next, we deliberate limit characteristic of DC motors that are suitable for Multi-DOF Jumping Robot design, and derive equations that express the limit characteristic. At last, we present one set of practical design parameters, and show simulation results of normal jump and somersault.

View full abstract