Hideharu Okano

Flexor mechanism of robot arm using pneumatic muscle actuators

This paper focuses on explaining the proposition of an actuator system using a pneumatic artificial muscle and a robot arm we developed. The pneumatic artificial muscle is light weight, and has high output and flexibility. Therefore, by incorporating this into the actuator of a robot arm, a light and flexible mechanism can be created and protection against collision etc. can be ensured. However, in the case of automatic balancing using a simple pneumatic artificial muscle as an actuator, it is difficult to realize enough joint drive angle, because the contractive capability of the artificial muscle is limited. In this study, the structure of the pneumatic artificial muscle and the contraction characteristics are described and the structure of the actuator system offset - posting the newly devised artificial muscle is explained. In addition, the test results for contraction characteristics and system effectiveness are shown. From function tests of the robot arm designed based on the above characteristics, we confirmed the system has a joint drive angle equal to the human arm.

Mechanisms of Autonomous Pipe-Surface Inspection Robot with Magnetic Elements

In this paper, we propose a pipe inspection robot to move automatically along the outside of piping. In recent years, such pipe inspection robots and climbing robots have been the subject of important research activity worldwide [1]-[3]. Inspection of industrial pipe is a well-known and highly practical application of robotic technology. Robots especially designed to inspect the surface of pipe have recently been realized by some companies, and are in practical use as mechanical pipe inspection devices in various plants. Some of the robots have the capability of self-propelled inspection. These robots are equipped with ultrasonic diagnostic equipment that can measure the thickness of the pipe along its surface [4]. However, they are able to move by manual operation only. Such robots cannot be applied to pipes with flanges and valves, etc. We have designed a mechanism that enables robots to traverse flanges, rise along vertical flanges, and move along the underside of the piping [5]-[8]. The proposed robot is composed of three connected units.

Design of Magnetic Wheels in Pipe Inspection Robot

In an industrial plant, straight piping, vertical piping, curved piping, valves, and flanges are arranged in complex patterns. Problems regarding automated pipe inspection originate in the fact that sensors cannot scan complex piping schemes involving flanges, valves, curved piping, and vertical piping. Various types of pipes are used in industrial applications, taking into consideration the temperature and the corrosive properties of the fluid. Oil plants, for example, use mainly carbon steel, stainless steel, and chloridized vinyl pipes. In light of this, we have focused on developing a robot that can inspect carbon steel pipes, having the ability to move automatically along the outside of a length of piping. This paper describes the structure of magnetic wheels used in a pipe inspection robot. We propose a robot that has a mechanism consisting of wheel-type magnets. Using the power generated by the magnets, the robot maintains its attachment to the pipe. The mechanism of the robot is composed of three units, and is able to automatically inspect a pipes surface, traverse flanges, and rise along vertical piping. To achieve the robots optimum performance, the design of the magnetic wheels is important. The authors have previously designed a similar robot composed of three connected units, though the adherence power of this robot was weak and could not achieve a high level of stability while advancing along a straight length of pipe.

Magnetic Part Design of Pipe-Surface Inspection Robot

In this paper, we propose a pipe-surface inspection robot to move automatically along the outside of piping. In dangerous heights, etc., in which a human cannot work, a pipe inspection robot is needed. In recent years, robots designed to inspect the surface of piping have been realised by various manufacturing industries, and are in practical use as mechanical pipe inspection devices in various plants. Some of the robots are equipped with ultrasonic diagnostic equipment that can measure the thickness of the piping along its surface. However, most robots are able to move by manual operation only. Such robots cannot be applied to pipes with flanges and valves, etc. We have designed a mechanism that enables robots to traverse flanges, rise along vertical flanges, and move along the underside of the piping. The proposed robot is composed of three connected units

Autonomous control of care and welfare robot

In this paper, we propose a robot that can perform nursing tasks in a hospital or welfare facility. When a narrow environment such as that of a sickroom is assumed, the robot must be able to move about freely in arbitrary directions, and should be able to correctly position itself in relation to its target. The robot has omni-directional mechanism, and has high controllability and the capability to make small turns. White lines originally set up on the floor, such as those indicating a safe passage area or the centerlines in the building, were used as the reference point of the robots guidance mechanism, and these lines are recognized using eight cameras. An optical wireless is used so as not to cause bad influence for the person who applied the heart pacer. As well, wireless correspondence between the robot and an operator enables the robots autonomous movement in a hospital.

Development of an omni-directional mobile robot with two or more cameras and navigation based on cell map information

This paper describes the development of a robot that can perform nursing tasks in a hospital or a welfare facility. In a narrow environment such as a sickroom or a hallway in the hospital, the robot must be able to move freely in arbitrary directions to execute the tasks. To achieve precise tasks, the robot needs to have high controllability and the capability to make precise movements. The proposed robot has four independent wheels. It can be controlled in the reference directions by means of comparisons of the position of the edge between the floor and wall in a hallway, original cell map information, and other specific targets extracted from the wall, and thus moves safely using two or more of its eight cameras, without any permanent induction line established in the building. Wireless communications between the robot in the patient room and a host computer in a control center such as a nurse station enables the robots autonomous movement everywhere in the hospital. In an actual experiment, the robot navigated a hallway by switching cameras and using both cell map information and recognition of a specific target

Grasping Force Control in consideration of Translational and Rotational Slippage by a Flexible Sensor

This paper addresses the issue of translational and rotational slippage that occurs when a robot hand grasps an object. To grasp an object against each directional slippage is an important task. In this study, to deal with rotational slippage, a contact area between a flexible contact sensor which is mounted on the robot hand and the object is considered. A sufficient condition for grasping an object against translational and rotational slippage is derived on condition that no additional sensors, such as tactile sensors, are required. An effectiveness of the condition is confirmed by a grasping experiment with the use of a translational gripper where the flexible contact sensor is mounted

Development of a flexible structural contact force sensor for a grasping task by robot hand

In this paper, we propose a new type of contact force sensor. This sensor can detect contact location and can measure four-axis contact forces. The contact part of this sensor is composed of a silicon rubber, allowing this sensor to contact to objects softly. The structure of this sensor and the methods for calculating the contact location and the four-axis contact forces are proposed. A flexible structure is one of the characteristics of this sensor. We confirm if this character is available to absorb impact force when the sensor and environment are in contact. In addition, the effectiveness of this sensor in a task involving the grasping of an object by a robot hand is also demonstrated.

Calculation of deformation of a flexible contact sensor

This paper describes the calculation of deformation of a flexible contact sensor. Approximate expressions to calculate the deformation of a flexible sensor are derived using Castiglianos theorem. Deformation of the flexible sensor is calculated in real-time with the use of measured contact forces. Measurement accuracy is confirmed experimentally. The experimental results show that the calculated deformation agrees approximately with the actual deformation. With the aim of applying this calculated deformation to certain robot tasks, the flexible sensor is attached to a robot hand, and the mechanical impedance parameters of a grasped object are estimated with the use of a Kalman filter. This grasping experiment demonstrates that these parameters are estimated exactly.

Development of a robot for the detection of plastic dangerous objects

In this paper, we propose a robot which detects dangerous articles made of plastic. To detect plastic articles, a corona charger is installed on a robot. The corona charger consists of corona wire through which high voltage is charged. The dangerous articles are identified by the detection of different surface potential by the difference of the electrification series when the corona is applied to the object. A vehicle was developed as a prototype machine. This vehicle has two driving systems; one is the mechanism with two motors and four castors, another one is a motor which moves the sensor up and down.