Koichi Suzumori

Development of flexible microactuator and its applications to robotic mechanisms

A flexible microactuator (FMA) driven by an electropneumatic (or electrohydraulic) system has been developed. The FMA has three degrees of freedom, pitch, yaw, and stretch, and these are suitable movements for miniature robotic mechanisms such as fingers, arms, or legs. The construction is of fiber-reinforced rubber, and the mechanism is very simple. Gentle miniature robots with no conventional links can be designed using this design. The FMAs basic characteristics and its applications to certain robot mechanisms are presented. Serially connected FMAs act as a miniature robot manipulator. The kinematics and control algorithm for this type of robot are presented. FMAs combined in parallel act as a multifingered robot hand, with each FMA representing a finger. An algorithm for the cooperative control of such FMAs, the stable region for holding, and its performance are presented.<<ETX>>

Applying a flexible microactuator to robotic mechanisms

A flexible microactuator (FMA) driven by an electropneumatic (or electrohydraulic) system has been developed. It has three degrees of freedom-pitch, yaw, and stretch-making it suitable for robotic mechanisms such as fingers, arms, or legs. It is made of fiber-reinforced rubber, and the mechanism is very simple, enabling miniature robots without conventional link mechanisms to be designed. Serially connected FMAs act as a miniature robot manipulator. The kinematics and control algorithm for this type of robot are presented. FMAs combined in parallel act as a multifingered robot hand, with each FMA representing a finger. An algorithm for the cooperative control for such FMAs, the stable region for holding, and its performance have been developed.<<ETX>>

Micro inspection robot for 1-in pipes

A micro inspection robot for 1-in pipes has been developed. The robot is 23 mm in diameter and 110 mm in length and is equipped with a high-quality micro charge-coupled device (CCD) camera and a dual hand for manipulating small objects in pipes. It can travel through both vertical pipes and curved sections, making possible inspections that would be difficult with conventional endoscopes. Its rate of travel is 6 mm/s and it has a load-pulling power of 1 N. To realize this microrobot, the authors have specially designed and developed several micro devices and micromechanisms: a novel micromechanism called a planetary wheel mechanism for robot drive; a micro electromagnetic motor with a micro planetary reduction gear to drive the planetary wheel mechanism; a micro pneumatic rubber actuator that acts as a hand; a micro CCD camera with high resolution; and a pneumatic wobble motor for rotating the camera and hands. In the paper, the design and performance of these micro devices are reported, the performance of the robot as a whole is described, and an application example is given.

A Bending Pneumatic Rubber Actuator Realizing Soft-bodied Manta Swimming Robot

This paper shows a new design and prototyping method for a bending pneumatic rubber actuator and its application to a soft-bodied manta swimming robot. The design is based on optimal design using non-linear finite element method, in which geometrical and material non-linearity are considered and fabrication process is based on a rapid and efficient prototyping system using a CAD/CAM based rubber molding process. In this paper, the characteristics of several possible actuators are analyzed and evaluated to lead to an optimal actuator design. The actuator works very well with smooth and soft motion. The manta swimming robot in which the developed actuators are embedded is also designed based on non-linear finite element method. The developed manta swimming robot is made only of rubber and it swims in water smoothly as if it was a living fish. The experimental results of the manta robot motion show that good agreement with those of analytical results.

Flexible microactuator for miniature robots

A new type of flexible microactuator (FMA) has been developed for use in miniature robots. They are constructed using fiber-reinforced rubber and are actuated by an electropneumatic or electrohydraulic system. These microactuators have many degrees of freedom (including pitch, yaw, and stretch), making them suitable for robotic mechanisms such as arms, legs, or fingers. Pliant miniature robots can be created by combining FMAs. One example is a robot arm a few millimeters in diameter with seven degrees of freedom. The basic characteristics of the FMAs have been analyzed theoretically and experimentally. It is noted that, since the statistics and dynamics are predicted easily, FMAs can be designed efficiently.<<ETX>>

Elastic materials producing compliant robots

Abstract A lot of research has been conducted on producing compliant robots by applying software algorithms such as force controls and compliance controls, while little research has been done in applying soft materials to robot mechanical designs. The author believes that the use of soft materials has great potential for producing compliant robots which are cheap and reliable. This paper reports on a new pneumatic rubber actuator and its applications to robot mechanisms. This actuator is made of silicone rubber and is called a flexible microactuator, an FMA. It has good compliance properties resulting from the elasticity of the materials and the compressibility of air.

Miniature Pneumatic Curling Rubber Actuator Generating Bidirectional Motion with One Air-Supply Tube

Soft actuators driven by pneumatic pressure are promising actuators for mechanical systems in medical, biological, agriculture, welfare fields and so on, because they can ensure high safety for fragile objects from their low mechanical impedance. In this study, a new rubber pneumatic actuator made from silicone rubber was developed. Composed of one chamber and one air-supply tube, it can generate curling motion in two directions by using positive and negative pneumatic pressure. The rubber actuator, for generating bidirectional motion, was designed to achieve an efficient shape by nonlinear finite element method analysis, and was fabricated by a molding and rubber bonding process using excimer light. The fabricated actuator was able to generate curling motion in two directions successfully. The displacement and force characteristics of the actuator were measured by using a motion capture system and a load cell. As an example application of the actuator, a robotic soft hand with three actuators was constructed and its effectiveness was confirmed by experiments.

Electrostatic linear microactuator mechanism for focusing a CCD camera

A newly developed linear electrostatic microactuator mechanism employing a vibrating motion is described. In order to achieve a miniature charge coupled device (CCD) camera with autofocusing and zoom functions, we developed an electrostatic linear microactuator with a large movement range. In miniature CCD cameras, extremely thin electrostatic actuators are needed because the space available for the focusing mechanism is reduced. The moving part (slider) of this actuator is sandwiched between fixed electrodes (stator), is alternately attached and detached to these fixed electrodes, and actuates linearly on a macroscopic level. The fundamental feasibility of this vibrating motion mechanism was first confirmed in experiments. This actuator was then applied to the focusing mechanism of a miniature CCD camera. A microlens was fitted inside the slider and it was possible to adjust the focus by moving the slider (with microlens). The size of the prototype for the focusing mechanism is 3.6/spl times/4.6/spl times/8.0 mm, and a 2-mm movement range is achieved. The minimum driving voltage is 60 V and the maximum velocity is 1.0 min/s.

Miniature soft hand with curling rubber pneumatic actuators

In medical and biotechnology fields, soft devices are required because of their high safety from low mechanical impedance. FMA (Flexible Microactuator) is one of the typical soft actuators. It consists of fiber-reinforced rubber structure with multi air chambers and realizes bending motion pneumatically. It has been applied to robot hands, robot legs and so on. High potential of FMA has been confirmed by many experiments reported in several papers. However in fabrication process of the actuator, it is difficult to embed the reinforced fiber in the rubber structure. In this study, we aim at development of a fiber less FMA realizing quite large motion, which can be said curling motion, and a soft hand using the actuators. We design the actuator without fiber using nonlinear FEM (Finite Element Method) and derived efficient shape. The actuator is fabricated through micro rubber casting process including micro machining process for molds, micro vacuum rubber molding process and rubber bonding process with surface improvement by excimer light. Basic driving experiments of the actuator showed that it realized curling motion which agreed well with FEM results. And the actuator could grasp a fish egg without breaking. Additionally, we made a soft hand consisting of three curling actuators. This hand also could be manufactured by simple casting process. The developed hand works opening and closing motions well.

Fiberless flexible microactuator designed by finite-element method

The flexible microactuator (FMA) is a type of pneumatic rubber actuator with 3 degrees of freedom (DOF) developed by Suzumori (1991). It has been applied to various kinds of miniature robots. To achieve the required motion, conventional FMAs are made of a fiber-reinforced rubber, which makes the fabrication process complicated. The fabrication of FMAs from homogeneous rubber without fiber reinforcement is necessary if low-cost manufacture is to become a reality. In this paper, a new nonreinforced FMA design is developed using a nonlinear hyperelastic finite-element-method (FEM)-based sensitivity analysis. First, global analyses of FR/LA deformation are made for a wide range of design variables. This is important, to avoid falling into a local optimization. Next, precise optimization is carried out using a sensitivity analysis. Finally, a prototype of the fiberless FMA is fabricated and tested. This process demonstrates the feasibility of the new FMA design without fiber reinforcement, both theoretically and experimentally. This new design is suitable for mass fabrication of FMAs at low cost.