Minimally Invasive Surgery (MIS) is one of the most successful applications of surgical robots. Although the introduction of robotic technology has brought a number of benefits, further advancements in MIS are limited by the size and bending radius of instruments. In this paper, we present a compliant four degree-of-freedom manipulator that consists of elastic elements with partly thinner structures. The proposed mechanism allows the elastic element to deform locally, thus minimizing its bending radius while the low number of mechanical parts greatly contributes to its compactness. This paper describes the design strategy, optimization method using FEA, prototype implementation, and evaluations. The evaluations reveal high accuracy and repeat accuracy, which are key elements for robotic instruments in MIS. Further, the prototype is able to exert sufficient force and it is possible to perform a simulated needle insertion task using the manipulator, demonstrating the feasibility of the proposed mechanism.

The Rubber Hand Illusion is a well known multisensory illusion in which the participant feels their own unseen hand become a rubber hand that is placed at the position where their hand is supposedly placed, triggered by synchronized haptic stimuli on their hand and the rubber hand. Our previous study showed that a robotized 1-degree-of-freedom rubber hand in the form of a master-slave system significantly enhanced the illusion compared with the classic rubber hand illusion. The illusion gives the sense that the part of body becomes part of the robot - it is thus assumed that this multisensory illusion is a potentially effective way to increase intuitiveness, and therefore increase the operability of a multi-degrees-of-freedom master-slave system. To further investigate the concept, we built a multisensory illusion inducible microsurgical robotic system based on the findings of the previous study and conducted a series of psychophysical experiments. The experimental results reveal that the multisensory illusion and operability is significantly correlated.

In this paper, a new hand exoskeleton device using a three-layered sliding spring mechanism is presented. In contrast to state of the art hand exoskeleton mechanisms (typically link, wire or pneumatically driven), the proposed mechanism is driven through large deformations of the compliant mechanism body. The mechanism can be made compact and lightweight by adequately positioning the compliant elements. In addition, the mechanism is designed to distribute 1-DOF actuated linear motion into three rotational motions of the finger joints, which translate into natural finger flexion/extension. The primary application of the proposed mechanism is to provide robotic support during physical therapy at the hospital (e.g. Continuous Passive Motion). However, thanks to its light and wearable structure, the proposed device could also be used at home as an assistive/therapeutic device to support activities of daily living. We introduce the mechanical structure of the three-layered sliding spring mechanism, present a prototype implementation as a hand exoskeleton device, and provide a preliminary evaluation.

In this paper, a compliant parallel mechanism with high precision and a wide working area is presented. A compliant parallel mechanism is a parallel mechanism in which all of the joints are deformable elastic joints. The presented mechanism is composed of circular compliant joints that have been inspired by Drakaea, which is an orchidaceous species. From our analytical and experimental tests, it was revealed that these circular compliant joints have desirable characteristics for composing a compliant parallel mechanism. Based on these primary experimental results, we developed a 3-DOF compliant parallel mechanism for an optic component positioning machine. The prototype evaluation tests revealed the mechanism's advantageous characteristics.

In this paper, we introduce a further optimization of morphology of compliant joint based on FEM analysis for a compliant-parallel mechanism with a wide working area and a high accuracy. Compliant-parallel mechanism is the mechanism that all joints are composed by compliant joints in a parallel structure. In the integration of compliant and parallel mechanism, the motion of compliant joints can be guided by mechanical constraints from the parallel structure; thus the mechanism can be precisely driven. However, since compliant joints generally have a limited working area due to limitation in their structural deformation, the working area is commonly limited in micrometer-scale. Designing the compliant joints within a wide range of working area presents us a new challenge: the joints should be elastic for the desired direction, but also rigid for non-desired direction to be deformed. From these requirements, the morphology of the compliant joint was optimized by FEM analysis, and newly serially layered-flat spring compliant joint was developed. The developed compliant joint was implemented on a parallel mechanism as a high precision micro-assembly system for optical components. The prototype enabled 50×50×5 mm of working area within 0.71 mm of repeatable accuracy. From these results, the effectiveness of the morphological optimization for compliant joint was shown.

Robotics has been supplemented by the growing body of techniques associated with formal languages. One remaining challenge for bottom-up formal methods is to provide effective abstractions to their top-down counterparts in order to achieve a seamless integration. This paper describes our efforts to tackle this challenge in the domain of spatial behavior. Our general goal is to understand principles involved in the formation of hierarchic representations that can greatly simplify the control and planning tasks. We propose that this hierarchy be built from the bottom-up according to formal language principles, while incorporating principles from dynamical systems theory. The general idea is that relevant interactions between the agent's dynamics, task and environment are manifested as patterns. Compared to other approaches these patterns are not based on abstract, high-level constructs but convey a form of meaning that inherently ties the system's dynamics, environment and task characteristics. Understanding the natural principles underlying hierarchic organization of behavior is a fundamental step toward developing formal languages dealing with dynamical systems. It can be applied to help understand spatial intelligence and eventually help design more versatile and adaptive agents.

A number of haptic devices have recently become available on the commercial market, and these devices are becoming common not only in research but in consumer use as well. In this paper, a new parallel mechanism, referred to herein as DELTA-R (meaning DELTA-Redundant, formerly referred to as DELTA-4) is proposed for a new haptic device having high-quality force display capability and operability. DELTA-R allows three-degree-of-freedom (DOF) translational motions. The key features of DELTA-R, as compared with conventional parallel mechanisms, are redundant actuation, a smaller footprint, a larger working area, and improved access to the end effector. The prototype is equipped with a 3-DOF rotation mechanism, the center of motion of which is located on the wrist position of the operator. An evaluation test of the force display was conducted using a prototype of the proposed mechanism. This paper describes the kinematic design, kinematic modeling, kinematic analysis, prototype implementation, and evaluations.

In recent years, robotic technology has been introduced to medical fields and many surgical robots have been presented not only in academic fields but also as commercialized products. In this paper, an outer shell type 2 DOF bending manipulator using a spring-link mechanism is presented. The mechanism was developed for a surgical robot, which can implement various surgical treatment devices inside of the manipulator. The spring-link mechanism is a simple combination of a flat spring and a rigid link with a passive joint connection. The outer shell type 2 DOF bending manipulator is composed by four spring-link mechanisms. The most unique feature of the manipulator is that these four springs are interconnected in the kinematics. Therefore, it is possible to realize a robust and backlash-free motion by taking into account the interconnections of springs such as an internal stress of the structure. In addition, by locating four spring-link mechanisms around the manipulator, it is possible to place medical devices inside of the manipulator.

In this paper, we investigate the position control of spherical ultrasonic motor (SUSM). The generated torque of SUSM is influenced by the phase difference and the driving frequency of applied AC voltages. Therefore, the control strategy is classified into three types: (a) variable phase and fixed frequency, (b) fixed phase and variable frequency, and (c) variable phase and frequency. We formulate the position control rules for SUSM based on the above three types of control variables, and investigate the performances experimentally.

Nowadays, several haptic devices are commercialized and becoming common not only in research fields but also in consumer use. In this paper, a new parallel link mechanism “DELTA-4” is proposed for a new haptic device within high quality force display capability and operability. DELTA-4 consists of 3 DOF of translational motions. The key features of DELTA-4 comparing with conventional parallel link mechanisms are: a redundant actuation, a wide working area and a small footprint. The prototype is equipped with a 3 DOF of rotation mechanism, which its center of motions is located on the wrist position of an operator. An evaluation test of force display was conducted on a prototype of DELTA-4 mechanism.

Remote surgery is one of the most desired applications in the context of recent advanced medical technologies. For a future expansion of remote surgery, it is important to use conventional network infrastructures such as Internet. However, using such conventional network infrastructures, we are confronting time-delay problems of data transmission. In this paper, a remote surgery experiment between Japan and Thailand using a research and development Internet is presented. In the experiment, the image and audio information was transmitted by a newly developed low latency CODEC system to shorten the time-delay. By introducing the low latency CODEC system, the time-delay was shortened compared with the past remote surgery experiments despite the longer distance. We also conducted several network measurements such as a comparison between TCP/IP and UDP/IP about the control signal transmission.

Several robotic surgical systems have been developed for MIS (minimally invasive surgery) including commercialized products such as da Vinci and ZEUS. We have developed a minimally invasive surgical system, which have carried out remote surgery experiments for five times at the writing time. In this paper, a remote surgery experiment, which was conducted between Japan and Korea by using the developed minimally invasive surgical system is described. Research & Development (R & D) Internet testbet, APII (Asia-Pacific Information Infrastructure), which consists of an optical submarine cable network KJCN (Korea-Japan Cable Network), was used. In the experiment, a laparoscopic cholecystectomy was successfully carried out on a pig. The network time-delays of control signal and images were 6.5 msec and 435.5 msec respectively. A comparison of remote surgery experiments using ISDN and the Internet was studied

Several robotic surgical systems have been developed for minimally-invasive surgery including commercialized products such as da Vinci and ZEUS. We have developed a minimally-invasive surgical system, which had performed remote surgery experiments for four times until now (performed on pigs over 150 km in Japan). In this paper, two approaches that extend the system from the perspective of extensions of surgeon's dexterity are described. The first approach is a development of complex robotic forceps, which have multiple d.o.f. on their tip. A complex rigid link mechanism has been applied to the robotic forceps to realize 3 d.o.f. motions in a patient's abdominal cavity. With the rigid link mechanism, surgeons have no longer need to be concerned a cable cutting problem, which often can be happened on conventional cable driven systems. The second approach is a force feedback capability. The developed rigid link mechanism is preferable for an implementation of a force feedback capability. The force feedback capability is important not only for extending surgeon's dexterity but also for preventing unexpected damage on internal organs. An evaluation experiment of the force feedback capability on a simulated surgical procedure was conducted. An augmented force presentation method was developed that displays contact information between forceps and soft tissues. In an evaluation experiment, the load applied to soft organ tissues was reduced by approximately 30% compared with a conventional force feedback method.

This paper describes a tele-endoscopic surgical system with force feedback capability. The system consists of multi-media cockpit, surgical site and communication link. The multimedia cockpit is equipped with force feedback type master manipulators, visual and auditory information presentation apparatuses, and foot switches. A slave manipulator with 3 arms is located at the surgical site; the left and right arms hold forceps or a radio knife and the center arm holds an endoscope. The slave manipulator has a special safety mechanism. Vital signs can be also transmitted to the cockpit. In the experiment, a cholecystectomy was successfully performed on a pig at the distance of 150 km.