Tomoaki Yano

Development of a semi self-contained wall climbing robot with scanning type suction cups

A semi self-contained wall climbing robot with scanning type suction cups is developed and rested. This robot has two vacuum pumps on it. The robot is connected to the equipment on the ground only through the electric power cables and information cables. From the experimental results, the robot can walk around on walls, clear steps, and stick on cracks and gaps. The walking speed attains 138 cm/min, which is 59% faster than the wall climbing robot I with tubes connected to the external vacuum pump on the ground. These experimental results show higher possibility towards the development of a complete self-contained wall climbing robot by putting a battery and a CPU on the robot.

Basic characteristics of the small spherical stepping motor

A small spherical stepping motor with two degrees of freedom is developed. The motor is composed of two sub stepping motors. Each submotor is the two-phase permanent-magnet bipolar linear stepping type and the shape is semi-circle. The rotational axes of two submotors cross at the same point, and this structure enables the developed motor to move in any direction. The size of the motor is 75/spl times/75/spl times/68 mm. The positioning resolutions of the inner and the outer submotors are 0.01deg and 0.03deg respectively and the holding torques of the inner and outer submotors are 0.2Nm and 0.03Nm respectively. The feature of the small torque and the high positioning resolution of the motor are suitable to apply it to the robotics eyes with small CCD camera.

Basic characteristics of the developed spherical stepping motor

The positioning accuracy, output torque, and the trajectory tracing property of the developed spherical stepping motor are tested. The motor is composed of two arc-shaped stepping submotors and a rotational stepping submotor. The rotational center of each submotor is identical. The following characteristics are derived from the experimental results. The positioning resolutions of the inner, middle, and outer submotors are 0.00781[deg], 0.00586[deg] and 0.00586[deg] respectively. The holding torques of the inner, middle, and outer submotors are 0.093[Nm], 0.38[Nm] and 2.06[Nm] respectively. It can trace along the circle and the radiation trajectory within 0.2[deg] error, and the star trajectory within 0.4[deg] error. In comparison with a spherical synchronous motor, the positioning resolution is better but the torque/diameter ratio is smaller.

Development of a spherical stepping motor rotating around six axes

Spherical motors have an advantageous feature that they can rotate around multiple axes. From the advantage, spherical motors are expected to be applied to driving mechanisms of holonomic mobile robots, joints of robots, and so on. This study develops a spherical motor called 14–12 spherical stepping motor that can rotate around 6 axes. This paper describes the structure of the motor, rotation principle by five-phase ACs (Alternative Currents), a five-phase AC power supply, and rotation experiments to confirm the applicability of the motor.

Basic Characteristics of a Multi-pole Spherical Synchronous Motor

A multi pole spherical synchronous motor is developed and tested. The developed motor has a rotor supported by a gymbal mechanism and a stator with two pairs of armature poles. 260 Small permanent magnets are attached on the rotor surface so that the North poles and the South poles appear on the concentric circles alternatively. Four armature winding units are positioned on the stator. Each armature winding unit has three windings. The pitch of the windings is 2/3 of the pitch of permanent magnets. Therefore, locally, the relation between the armature windings and the permanent magnets is almost the same as that of the conventional multi pole synchronous motor. The motor size is 265 times 265 times 266 [mm] and the diameter of the rotor is 130 [mm]. The target maximum output torque is 0.49 [Nm], The motor has two degrees of freedom and the working area is plusmn45 [deg] around x and y axis. The rotor can rotates around x and y axis and also moves in the direction combining two rotations simultaneously. The motor is driven by two pairs of three phase sinusoidal currents, each amplitude is calculated at the DSP board. The repeated positioning accuracy, the moving speed, and the output torque of the vertical position were tested. The maximum repeated positioning error was 0.00348 [deg]. The maximum moving speed was more than 90 [deg/sec], and the output torque is more than 0.59 [Nm]. Additional trajectory control results also showed small positioning errors.

Basic characteristics of a hexahedron-octahedron based spherical stepping motor

A spherical stepping motor with a hexahedron based rotor and an octahedron based stator is developed. The drive principle of the developed spherical motor is an expansion of the drive principle of a conventional stepping motor. The motor has three degrees of freedom. As the motor structure is spherically symmetric, the control method is same and simple in any direction. The experimental results show that the rotor moves in almost any direction by switching the connection between the three phase currents of the conventional motor driver and the armature coils. The motor speed is controlled from 0.05rpm to 180rpm and the maximum output torque is 0.013Nm. The developed motor is air-cored type without back yoke. Iron-cored, back yoked spherical motor will be an omnidirectionaly high torque spherical motor. A group of the polyhedron based spherical stepping motors is also introduced.

Multi dimensional drive system and their applications

This paper reports on the recent development and application of the multi dimensional system. At first, classify the multi dimensional drive system by the drive principle. The advantages of the multi dimensional drive systems are shown. The problems of the multi dimensional drive system are discussed. Researches of the multi dimensional drive systems are reviewed briefly. Finally, the recent and future applications of the multi dimensional drives are presented

Proposal of polyhedron based spherical stepping motors

A novel stepping motor principle based on a pair of polyhedrons are proposed. At first, I will show the goal of my study and the design concept of high torque spherical motor. Next, the principle of the conventional stepping motor is reviewed. Then, I will explain how to expand the principle of the conventional stepping motor to the three dimensional space with an example of a regular dodecahedron and a truncated octahedron based spherical stepping motor. Some polyhedrons are introduced for the candidates of making the polyhedron based spherical stepping motor. The proposed spherical stepping motors will be wide working area and high-torque.

Proposal of a truncatedoctahedron-dodecahedron based spherical stepping motor

A novel stepping motor principle based on a pair of truncatedoctahedron and dodecahedron is proposed. At first, the advantages of the spherical motor are presented. Then, the goal of the spherical motor project is shown. Next, the principle of the conventional stepping motor is reviewed. Then, expand the principle of the conventional stepping motor to the three dimensional space with an example of a truncatedoctahedron and a regular dodecahedron based spherical stepping motor. Some polyhedrons are introduced for the candidates of making another polyhedron based spherical stepping motors. The proposed spherical stepping motors will be wide working area and high-torque.

Development of a high torque spherical motor (2nd Report: Proposal of a hexahedron-octahedron based spherical stepping motor)

A novel stepping motor principle based on a pair of polyhedrons are proposed. At first, I will show the goal of my study and the design concept of high torque spherical motor. Next, the principle of the conventional stepping motor is reviewed. Then, I will explain how to expand the principle of the conventional stepping motor to the three dimensional space with an example of a regular hexahedron and a regular octahedron based spherical stepping motor. Some polyhedrons are introduced for the candidates of making the polyhedron based spherical stepping motors. The proposed spherical stepping motors will be wide working area and high-torque.