New actuators and their applications: from nano actuators to mega actuators

The present report describes R&#38;D activities on new actuators undertaken at our laboratory at Okayama University for the past three years. These activities include various types of actuators, such as electromagnetic, electrostatic, piezoelectric, pneumatic, and hydraulic actuators, ranging in size and force from the nano to the mega range. These actuators are described in four categories: microactuators, power, intelligence, and novel principle.</p

Development of intelligent McKibben actuator

The aim of this study is to develop an intelligent McKibben actuator with an integrated soft displacement sensor inside, so that displacement of this actuator can be controlled without having any extra devices attached. In addition, the high compliance which is a positive feature of the McKibben actuator is still conserved. This paper consists of four main parts. First of all, different types of soft displacement sensors made out of rubber were composed, and tested for their functional characteristics. Secondly, the intelligent McKibben actuator was developed with the soft displacement sensor incorporated within. Then, experiments of the position servo control with a single intelligent McKibben actuator were carried out. At last a robot arm mechanism was designed with two intelligent McKibben actuators, and those experimental results showed a great potential for its future applications.</p

A miniature inspection robot negotiating pipes of widely varying diameter

The purpose of this research is to realize a small robot which can negotiate pipes whose diameter varies widely during the robot's course. A new in-pipe locomotion mechanism named &#34;snaking drive&#34; is proposed in this paper and its potential and fundamental characteristics are shown with experimental data of the prototype model. First, in the sections 2 to 5, the basic traveling characteristics of the snaking drive mechanism are discussed: a theoretical formula of the fundamental characteristics and control algorithm are derived, the motions of the robot are simulated on a PC, and the prototype model was designed, developed, and tested. Next, in the sections 6 and 7, additional control algorithms for the front link are derived. They are necessary for steering at T-branches and L-bends of pipes, and also for camera view stabilization. Their performances are also shown by software simulation and experiments. The prototype robots moved in pipes whose diameter varies between 55 mm to 331 mm with the maximum speed of 22 mm/s. The paper also shows that the prototype negotiates T-branches and L-bends of pipes with inspection capability through a camera mounted on the robot.</p

Development of intelligent McKibben actuator with built-in soft conductive rubber sensor

This study aims at the development of an intelligent McKibben actuator, in which a soft rubber displacement sensor is integrated. Recently, the McKibben actuator has attracted engineers because of light weight, high output power and high compliance. But in the case of using it for servo control at present, the systems need encoders or potentiometers, therefore the systems tend to grow in size and take away from compliance which is an important advantage for a safe and secure mechanism. We have developed a soft displacement sensor and incorporated it in a McKibben actuator, named it the intelligent McKibben actuator, and proved its potential.</p

Nutation motor : a new direct-drive stepping motor for robots

A new type of stepping motor, named nutation motor was developed. This motor has a reduction mechanism consisting of a pair of bevel gears, realizing high torque and high resolution stepping motion. Three prototypes, two pneumatic nutation motors and an electric nutation motor, were designed, developed, and tested. We show the basic driving principle and the experimental results in this paper.</p

Pneumatic direct-drive stepping motor for robots

A new type of pneumatic stepping motor, named pneumatic nutation motor, was developed. This motor achieves stepping positioning of 720 steps/rotation without any electrical devices or sensors mounted on the servo mechanisms. This makes the motor possible to be used under hazardous conditions such as in water and in strong magnetic fields where conventional electromagnetic motors cannot be used. The motor torque is so big that the motor can be used as a direct motor. In this report, the driving principle and design of this motor are presented. Its characteristics are analyzed experimentally and theoretically. The motors were applied to a parallel linkage mechanism with six degrees of freedom. The mechanism shows that the pneumatic nutation motors can be used as a direct servo motor for robot mechanisms.</p

A cylindrical micro ultrasonic motor using micro-machined piezoelectric vibrator

A micro ultrasonic motor using a micro-machined cylindrical bulk piezoelectric vibrator is introduced. This motor consists of the vibrator, a glass case and a rotor. The diameter of the piezoelectric vibrator is 0.8 mm and that of the motor case is 1.8 mm. Since the stator transducer is fixed at the end of the cylinder, it is easy to support the vibrator and the structure of the motor is not complicated. In addition, the vibrator and rotor are supported by the glass case. This is important for the micro ultrasonic motor because it is difficult to support the vibrator when the vibrator is miniaturized. We have fabricated and evaluated the cylindrical shaped traveling type micro ultrasonic motor using this vibrator.</p

A miniature inspection robot negotiating pipes of widely varying diameter

Abstract The purpose of this research is to realize a small robot which can negotiate pipes whose diameter varies widely during the robot&apos;s course. A new in-pipe locomotion mechanism named &quot;snaking drive&quot; is proposed in this paper and its potential and fundamental characteristics are shown with experimental data of the prototype model. First, in the sections 2 to 5, the basic traveling characteristics of the snaking drive mechanism are discussed: a theoretical formula of the fundamental characteristics and control algorithm are derived, the motions of the robot are simulated on a PC, and the prototype model was designed, developed, and tested. Next, in the sections 6 and 7, additional control algorithms for the front link are derived. They are necessary for steering at T-branches and L-bends of pipes, and also for camera view stabilization. Their performances are also shown by software simulation and experiments. The prototype robots moved in pipes whose diameter varies between 5 5 m m to 331mm with the maximum speed of 22 d s . The paper also shows that the prototype negotiates T-branches and L-bends of pipes with inspection capability through a camera mounted on the robot

Design of a variable-stiffness robotic hand using pneumatic soft rubber actuators

In recent years, Japanese society has been ageing, engendering a labor shortage of young workers. Robots are therefore expected to be useful in performing tasks such as day-to-day support for elderly people. In particular, robots that are intended for use in the field of medical care and welfare are expected to be safe when operating in a human environment because they often come into contact with people. Furthermore, robots must perform various tasks such as regrasping, grasping of soft objects, and tasks using frictional force. Given these demands and circumstances, a tendon-driven robot hand with a stiffness changing finger has been developed. The finger surface stiffness can be altered by adjusting the input pressure depending on the task. Additionally, the coefficient of static friction can be altered by changing the surface stiffness merely by adjusting the input air pressure. This report describes the basic structure, driving mechanism, and basic properties of the proposed robot hand