パラレルリンク機構を用いた5自由度HEM<sup>2</sup>の開発

This paper is the first in a two-part series analyzing human arm and hand motion during a wide range of unstructured tasks. The wide variety of motions performed by the human arm during daily tasks makes it desirable to find representative subsets to reduce the dimensionality of these movements for a variety of applications, including the design and control of robotic and prosthetic devices. This paper presents a novel method and the results of an extensive human subjects study to obtain representative arm joint angle trajectories that span naturalistic motions during Activities of Daily Living (ADLs). In particular, we seek to identify sets of useful motion trajectories of the upper limb that are functions of a single variable, allowing, for instance, an entire prosthetic or robotic arm to be controlled with a single input from a user, along with a means to select between motions for different tasks. Data driven approaches are used to discover clusters and representative motion averages for the wrist 3 degree of freedom (DOF), elbow-wrist 4 DOF, and full-arm 7 DOF motions. The proposed method makes use of well-known techniques such as dynamic time warping (DTW) to obtain a divergence measure between motion segments, Ward's distance criterion to build hierarchical trees, and functional principal component analysis (fPCA) to evaluate cluster variability. The emerging clusters associate various recorded motions into primarily hand start and end location for the full-arm system, motion direction for the wrist-only system, and an intermediate between the two qualities for the elbow-wrist system.

Torque control of a spherical machine combining three degrees of freedom in motion is presented. This drive can be used for machine tools and robots to replace conventional rotating or linear machines which are connected in series or parallel. The proposed motor consists of a rotor sphere with permanent magnets and an outer stator core casing with 96 stator poles and windings. The currents of the coils have to be controlled individually because the pole pitch varies during operation. A unique solution to calculate all 96 current commands to produce one desired torque does not exist. Different control algorithms are presented on how to choose the individual phase currents to reach the required torque vector. Simulation showed satisfactory results which are confirmed by experiments. In addition, the controllability of three dimensional motion is demonstrated.

We synthesized two kinds of poly(9,9-diochtylfluorene) (PDOF) with different molecular weight distribution. One is PDOF with low weight molecular component (PDOF-l) and the other is PDOF with high molecular component (PDOF-h). The latter showed twice higher PL efficiency than the former. We investigated PL spectra and EL properties of the blended specimens of two PDOFs. The increase in PDOF-l content reduced PL intensity, conduction current at a constant voltage, and EL efficiency. We suggested the model due to excimer formation caused by the degree of freedom in motion of edge groups.

The planar motor and the spherical motor presented in this paper possess three degrees of freedom in motion. For this type of motor, special drive components and new control algorithms have to be developed because the machine operates with a variable pole pitch. The implemented control uses nonlinear force characteristics to control force and torque. It is proven that position control can be very accurate, despite the fact that the calculated and measured force characteristics contain uncertainties and errors. Simulations and experiments show that the spherical motor offers a high force and torque generation capability combined with a very precise position control. A planar motor based on the same working principle was built first to test the components and control strategies.

DragonFlex – Smart Steerable Laparoscopic Instrument

Autonomous underwater vehicles (AUVs) are poised to become an indispensable tool for ocean exploration, underwater research and development, and military activities. One of the key elements of these vehicles is dependability; there must be some form of fault recovery/fault tolerance in the control system. In this work, we use an approach involving synthesis of motions in degrees of freedom (DOF) that are unactuated, by combining motions in DOF that are actuated. The objective is to determine the usefulness of the method for a typical streamlined vehicle which is controlled by control surfaces rather than thrusters. We find that the method has difficulties in its present form because of the righting moment designed into the vehicle, but it is functional on a modified model of the vehicle.

Surgical robots have been studied and developed to assist surgeons. Master-slave flexible forceps robots that are components of a flexible endoscopic surgical robot are useful to realize novel minimally invasive surgical procedures that are difficult for conventional rigid medical devices. Although driving force for the tip portion of a flexible forceps robot is mechanically transmitted by wires through the flexible portion, friction and backlash changed by the posture of the flexible portion make it difficult to realize precise end effector control. Furthermore, transmission of haptic sensation is necessary to realize safer operation. In this study, a multi degrees-of-freedom (DoF) haptic forceps robot with three fingers is presented as an end effector of a flexible forceps robot. Transmission of driving force in flexible structure that causes performance deterioration is eliminated by arranging motors near the end effector. To transmit haptic sensation to operators, bilateral control is implemented to a master-slave system composed of the haptic forceps robot and a multi DoF input device. Additionally, control on modal space is implemented to verify finger dexterity. The utility of the haptic forceps robot is experimentally validated.

This paper addresses determination of Degrees of Freedom (DOF) in any planar, spatial, or a combined planar-spatial mechanism. The mechanisms under study may have multiple planar and/or spatial closed loops, open chains with links in series, and/or a combination of the two. It is seen that equations available in the literature to calculate the DOF of such general mechanisms with special joint arrangements such as adjacent joints with parallel and/or intersecting axes over-predict the “true” mobility of links. To overcome this difficulty, new concepts as the Degrees of Freedom of Motion (DOFM) and Degrees of Freedom of Workspace (DOFW) have been introduced. The new definition of Degrees of Freedom of Motion yields a tight upper bound on the connectivity between any two links of a mechanism containing neighboring joints with parallel and/or intersecting joint axes.

Augmented robotic device for EVA hand manoeuvres

This paper presents the design, fabricate and evaluation of a Magnetic Resonance compatible finger rehabilitation device, which could not only be used as a finger rehabilitation training tool after stroke, but also to study the brain's recovery process during the rehabilitation therapy (ReT). The mechanics of this device are designed to be adjustable to different persons' finger phalanges, and also the gap between one finger to another can be easily changed. By using an ultrasonic motor as its actuator, the device has been designed to be portable, with a high torque output. In addition, the mechanical has been developed into two working models (passive and active) in order to overcome the intrinsic shortage of non-back drivability in ultrasonic motor. The result system enables the client to do extension and flexion rehabilitation exercises in two degrees of freedom (DOF) for each finger as well as one DOF motion on the thumb. Finally, experiment has been carried out to evaluate the performance of the device.

It is a challenging idea to measure and to analyse a person's handwriting dynamics in order to detect diseases at an early stage, to control medication, or to extend available therapies. This article makes an important move towards those biomedical applications of biometrics by showing that low temperature, physical strain, or writing with the non-preferred hand (mostly left) have a bearing on human hand movement. This is measurable even for very simple kinds of hand movement, e.g., when drawing repeated backslashes. The handwriting dynamics are measured by means of a pen equipped with force and tilt sensors. Then, the parameterized script generator model proposed by Hollerbach is used in order to extract characteristic features from the measured signals, e.g., features describing deviations of measured time series from predicted model time series. The features are then used as inputs of support vector machines that classify whether the handwriting has been influenced or not. In particular for a cooled hand this can be performed with a very high accuracy

The purpose of this research is to simulate high degree of freedom motions with low degree of freedom motions. It breaks the rule of using high degree of freedom to simulate high degree of freedom motions. Besides, except for using expensive servo slider, the study uses cables to control the simulator to reach the purpose of simulating unlimited space with limited space of the simulator and it also reach the demands of low cost. In the research, the operator’s tactile sense in body is simulated; the “visual helmet” is also added. Compared with the traditional infrared transmission, it is faster and the changes of the produced environments are more immediate. This makes the operator feels more realistic in the variation of the virtual scenes. The combination of the cable controlled simulator and the visual helmet with the software of virtual reality games makes the operator obtain more actual simulating effects in visual, audio feedback and tactile, motion feedback. It makes operator feel as if s/he is in the real world.

In this paper, a precise small 5-DOF (degree of freedom) force sensor is proposed for use in a strong EMF (electromagnetic field) environment. Detecting modules using CFPs (carbon fiber plates) and transducing modules using the optical modulation principle are adopted in order not to be affected by the EMF. For miniaturization of the multi-DOF force sensor, a 2-DOF transducing module using a spherical mirror and a 3-DOF transducing module using a plane mirror were designed and integrated. The design parameters of highly sensitive transducing modules were investigated and determined experimentally. To combine with these transducing modules, a 2-DOF detecting module using CFP single leaf springs and a 3-DOF detecting module using a CFP tripod spring were also designed. Considering the easy calibration process and convenient design change, the elastic detecting modules were designed so that they deform independently according to each input force component. A calibration test confirmed that the detecting modules deform linearly and independently of the input force. The results of the evaluation tests showed that the range and resolution of forces were ±4 N and 0.94–7.1 mN and the range and resolution of moments were ±120 N mm and 0.023–0.034 N mm, respectively. The high sensitivity and the linearity of the measuring results were also verified.

Vitreo-retinal surgery encompasses the surgical procedures performed on the vitreous humor and the retina. A procedure typically consists of the removal of the vitreous humor, the peeling of a membrane and/or the repair of a retinal detachment. Operations are performed with needle shaped instruments which enter the eye through surgeon made scleral openings. An instrument is moved by hand in four degrees of freedom (three rotations and one translation) through this opening. Two rotations (? and ? ) are for a lateral instrument tip movement. The other two DoFs (z and ?) are the translation and rotation along the instrument axis. Actuation of for example a forceps can be considered as a fifth DoF. Characteristically, the manipulation of delicate, micrometer range thick intraocular tissue is required. Today, eye surgery is performed with a maximum of two instruments simultaneously. The surgeon relies on visual feedback only, since instrument forces are below the human detection limit. A microscope provides the visual feedback. It forces the surgeon to work in a static and non ergonomic body posture. Although the surgeon’s proficiency improves throughout his career, hand tremor may become a problem around his mid-fifties. Robotically assisted surgery with a master-slave system enhances dexterity. The slave with instrument manipulators is placed over the eye. The surgeon controls the instrument manipulators via haptic interfaces at the master. The master and slave are connected by electronic hardware and control software. Implementation of tremor filtering in the control software and downscaling of the hand motion allow prolongation of the surgeon’s career. Furthermore, it becomes possible to do tasks like intraocular cannulation which can not be done by manually performed surgery. This thesis focusses on the master console. Eye surgery procedures are observed in the operating room of different hospitals to gain insight in the requirements for the master. The master console as designed has an adjustable frame, a 3D display and two haptic interfaces with a coarse adjustment arm each. The console is mounted at the head of the operating table and is combined with the slave. It is compact, easy to place and allows the surgeon to have a direct view on and a physical contact with the patient. Furthermore, it fits in today’s manual surgery arrangement. Each haptic interface has the same five degrees of freedom as the instrument inside the eye. Through these interfaces, the surgeon can feel the augmented instrument forces. Downscaling of the hand motion results in a more accurate instrument movement compared to manually performed surgery. Together with the visual feedback, it is like the surgeon grasps the instrument near the tip inside the eye. The similarity between hand motion and motion of the instrument tip as seen on the display results in an intuitive manipulation. Pre-adjustment of the interface is done via the coarse adjustment arm. Mode switching enables to control three or more instruments manipulators with only two interfaces. Two one degree of freedom master-slave systems with force feedback are built to derive the requirements for the haptic interface. Hardware in the loop testing provides valuable insights and shows the possibility of force feedback without the use of force sensors. Two five DoF haptic interfaces are realized for bimanual operation. Each DoF has a position encoder and a force feedback motor. A correct representation of the upscaled instrument forces is only possible if the disturbance forces are low. Actuators are therefore mounted to the fixed world or in the neighborhood of the pivoting point for a low contribution to the inertia. The use of direct drive for ' and and low geared, backdriveable transmissions for the other three DoFs gives a minimum of friction. Disturbance forces are further minimized by a proper cable layout and actuator-amplifier combinations without torque ripple. The similarity in DoFs between vitreo-retinal eye surgery and minimally invasive surgery (MIS) enables the system to be used for MIS as well. Experiments in combination with a slave robot for laparoscopic and thoracoscopic surgery show that an instrument can be manipulated in a comfortable and intuitive way. User experience of surgeons and others is utilized to improve the haptic interface further. A parallel instead of a serial actuation concept for the ' and DoFs reduces the inertia, eliminates the flexible cable connection between frame and motor and allows that the heat of the motor is transferred directly to the frame. A newly designed z-?? module combines the actuation and suspension of the hand held part of the interface and has a three times larger z range than in the first design of the haptic interface.

The family of [PP]S parallel mechanism consists of 3-PRS, 3-RPS, 3-RRS and 3-PPS parallel mechanisms, which can undergo one translational degree of freedom (DOF) and two rotational DOFs, and thus, has great potential in practical application. Parasitic motion is the motion occurring in the non-independent DOFs of a [PP]S parallel mechanism, which is a key issue affecting its application. The kinematic model of the parasitic motion of the general 3-PRS parallel mechanism is established, revealing the inherent link between the geometrical structural parameters and the parasitic motion. The sufficient and necessary structural condition for a 3-PRS parallel mechanism without parasitic motion is proved. Based on the structural condition, the 3-PRS parallel mechanism without parasitic motion can be constructed. Local mobility in the 3-PRS parallel mechanism without parasitic motion is identified. Actuation selection considering the local mobility is presented. Mobility analysis of the 3-PRS parallel mechanism without parasitic motion is performed and the two finite rotational axes of the moving platform are identified. The sufficient and necessary structural condition is applicable to all [PP]S parallel mechanisms.