Pneumatic Bellows Research Articles

Damage inspection of the first mercury target vessel of JSNS

The liquid mercury target system for the Japan Spallation Neutron Source (JSNS) began operating in May 2008. A mercury target vessel composed of type 316L stainless steel suffers radiation damage in the proton and neutron environment. In addition to this damage, the inner wall of the target vessel in contact with mercury is damaged by cavitation-induced erosion, which is caused by rarefied pressure waves. The target vessel was replaced with a new target in November 2011, because the pneumatic bellow type flange was damaged during the Great East Japan Earthquake, that occurred on March 11, 2011. Before replacing the target, 50mm diameter disk specimens were cut from the beam window of the target vessel in order to investigate the cavitation damage inside the target vessel and to evaluate the change in the mechanical properties due to radiation damage. A video camera was used to inspect the inside of the target vessel and no flow induced erosion damage was detected on the flow guide by visual inspection. Cavitation damage from the proton pulse was concentrated at the center and approximately 15mm from the center of the beam window. In addition, the depth of the cavitation damage was quantitatively measured using a laser profilometer and a metallurgical surface replica. Based on the detailed measurements, it was concluded that the eroded damage depth of the beam window was 250μm after 475MWh of operation.

Distribution of lung tissue hysteresis during free breathing

To characterize and quantify free breathing lung tissue motion distributions. Forty seven patient data sets were acquired using a 4DCT protocol consisting of 25 ciné scans at abutting couch positions on a 16-slice scanner. The tidal volume of each scan was measured by simultaneously acquiring spirometry and an abdominal pneumatic bellows. The concept of a characteristic breath was developed to manage otherwise natural breathing pattern variations. The characteristic breath was found by first dividing the breathing traces into individual breaths, from maximum exhalation to maximum exhalation. A linear breathing drift model was assumed and the drift removed for each breath. Breaths that exceeded one standard deviation in period or amplitude were removed from further analysis. A characteristic breath was defined by normalizing each breath to a common amplitude, aligning the peak inhalation times for all of the breaths, and determining the average time at each tidal volume, keeping inhalation and exhalation separate. Breathing motion trajectories were computed using a previously published five-dimensional lung tissue trajectory model which expresses the position of internal lung tissue, X, as: X(v,f:X0)=X0+α(X0)v+β(X0)f, where X0 is the internal lung tissue position at zero tidal volume and zero airflow, the scalar values v and f are the measured tidal volume and airflow, respectively, and the vectors α and β are fitted free parameters. In order to characterize the motion patterns, the trajectory elongations were examined throughout the subject's lungs. Elongation was defined here by generating a rectangular bounding box with one side parallel to the α vector and the box oriented in the plane defined by the α and β motion vectors. Hysteresis motion was defined as the ratio of the box dimensions aligned orthogonal to and parallel to the α vector. The 15th and 85th percentile of the elongation were used to characterize tissue trajectory hysteresis. The 15th and 85th percentile bounding box elongations were 0.090 ± 0.005 and 0.083 ± 0.013 in the upper left lung and 0.187 ± 0.037 and 0.203 ± 0.053, in the lower left lung. The 15th and 85th percentiles for the upper right lung were 0.092 ± 0.006 and 0.085 ± 0.013, and 0.184 ± 0.038, and 0.196 ± 0.043 in the lower right lung. Both percentiles were calculated for tidal volume displacements between 5 and 15 mm. In the left lung, the average elongations in the upper and lower lung were ζ=0.120 ± 0.064 and ζ=0.090 ± 0.055, respectively. The average elongations in the upper and lower right lung were ζ=0.107 ± 0.060 and ζ=0.082 ± 0.048, respectively. The elongation varied smoothly throughout the lungs. The hysteresis motion was relatively small compared to the volume-filling motion, contributing between 8% and 20% of the overall motion. Statistically significant differences were observed in the range of hysteresis contribution for upper and lower lung regions. The characteristic breath process provided an excellent method for defining an average breath. The characteristic breath had continuous tidal volume and airflow characteristics when the breath was continuously repeated,useful for generating patterns representative of realistic motion for breathing motion studies.

C25 空気圧ベローズを用いた多自由度微動ステージのためのアクチュエータユニットとその位置決め特性(M-OS5-1 空気圧制御の高度化,M-OS5 フルードパワーの基礎と応用,「海を越え,国を越え,世代を超えて!」)

The demand for ultra precise positioning of nanometer-order is increasing with the progress of nanotechnology in semiconductor industry. Previously we developed the one axis stage driven by pneumatic bellows for such a demand, and realized ultra precise positioning and long stroke. However, not only a one axis stage, but also a stage with multiple degrees of freedom is often demanded in semiconductor industry. In this paper, we proposed the actuator unit composed a bellows and elastic hinge guide, and show the fine movement stage with 3 degree of freedom applying proposed actuator units. The characteristics of the pneumatic bellows actuator unit are also evaluated and the positioning accuracy of the actuator unit is 50 [nm] or less, which is same level with the accuracy of one axis stage. It is found that the actuator unit can also realizes ultra precise positioning and long stroke though we must improve the control of the stage to eliminate the small vibration in the transient response.

Fluid-Power Harvesting by Under-Foot Bellows During Human Gait

Pneumatic and hydraulic bellows were investigated for under-foot power harvesting during human walking. Placement under the heel allows the bellow to be compressed during the heel strike of the gait cycle, whereas placement under the metatarsal allows compression during the mid-stance and toe-off phases. In either case, body weight is used as the power source for a self-contained fluid power circuit. Once unweighted, air is drawn into the bellow through a one-way valve allowing the bellow to recharge as it expands during the swing phase of the gait cycle. A collapsible spring was placed inside the bellow to ensure full opened conditions for this phase. To evaluate this concept, experimental studies were conducted on two circular bellows with outside diameters of 4.13 cm and 6.35 cm placed under the heel or the metatarsal of the foot, on a person walking on a treadmill. These pressure profiles were then reproduced on a compression testing machine to investigate the power generated per cycle. During normal walking, the pneumatic bellows generated peak power levels of 20–25 W and maximum pressures of 450 kPa. The average power available over a single cycle was 1.5 and 4.5 W for the small and large bellows, respectively. This novel use of bellows demonstrates the ability to use these devices for regenerative fluid power harvesting capabilities during walking.

A robotic colonoscope with long stroke and reliable leg clamping

Previously developed robotic colonoscopes have shown low locomotion performance since they have not had reliable clamping modules or a long stroke. Therefore, a clamping module consisting of six legs and two triggers is installed on the front and rear of the robot, enabling the robot to clamp effectively onto the colon. Locomotion capability is then improved via the on-time folding and unfolding of the legs according to the elongation and contraction of the bellows of the robot body. In addition, one pneumatic line based locomotive mechanism, which had been developed previously for in-pipe inspection, is adopted to reduce the friction force between the pneumatic lines and the locomotion environment. In order to evaluate locomotion performance, the robot and robot control system are constructed and are tested in an acrylic pipe and under condition of in-vitro. The robot can move regardless of slope in the case that the locomotion path has more than 25 mm of radius. In straight and vertical paths, it travels 33 mm/s and 12.1 mm/s, respectively. Next, a locomotion test under in-vivo condition is carried out with the optimized configuration and maneuvering parameters. Conclusively, a pneumatic bellows based locomotive mechanism with a dependable clamping module shows the reliable locomotion performance of about 8.5 mm/sec under in-vivo condition.

Curved Type Pneumatic Artificial Rubber Muscle Using Shape-Memory Polymer

A novel pneumatic artificial muscle actuator is presented which is based on the design of a conventional curved type pneumatic bellows actuator. By inhibiting the extension of one side with fiber reinforcement, bending motion can be induced when air is supplied to the internal bladder. In this study, we developed a new actuator by replacing the fiber reinforcement with a Shape-Memory Polymer (SMP). The SMP can be deformed above its glass transition temperature (Tg) and maintains a rigid shape after it is cooled below Tg. When next heated above Tg, it returns to its initial shape. When only part of our actuator is warmed above Tg, only that portion of the SMP is soft and can actuate. Therefore, the direction of the motion can be controlled by heating. Moreover, our actuator can be deformed by an external force above Tg and fixed by cooling it below Tg.

J113031 空気圧ベローズを用いた静圧案内微動ステージの超精密位置決め

The demand for ultra precise positioning of nanometer-order is increasing with the progress of nanotechnology in biotechnology industry and especially semiconductor industry. Previously we developed the elastic hinge guide stage driven by pneumatic bellows for such a demand, and realized ultra precise positioning with accuracy of 0.02±3.9 [nm]. Then, positioning accuracy was limited by the vibration from a floor with the resonance frequency which is decided by the mass of a stage and the spring of elastic hinges. On the other hand, the measurement of exact stage position by the laser interferometer is difficult because fluctuation of air influences to the measurement. In this research, guide was changed into the air bearing from the elastic hinge, and positioning measurement was changed into the laser scale from the laser interferometer in order to solve these problems. The purpose of this research is investigated the positioning accuracy the changed stage. As a result, the positioning accuracy is improved to 0.01 ±0.9 [nm] with the positioning resolution of l [nm] and the good positioning repeatability.

Ultra Precise Positioning of a Stage Driven by Pneumatic Bellows

Ultra precise positioning techniques that support nanotechnologies led by the semiconductor industry mainly require precision of nanometer order. Currently, it is piezoelectric elements that are most often used for positioning control of this order. Piezoelectric elements, however, are deficient in strokes and durability. In this research, we propose to use for ultra precise positioning control pneumatic bellows instead of piezoelectric elements, because the durability of pneumatic bellows is well proven. Specifically, we manufacture an elastic-hinge-guided, fine-motion stage which is driven by pneumatic bellows. In addition, we have developed a mathematical model for this fine-motion stage as well as its dynamic characteristics. We review feedback control to achieve ultra precise positioning, using the developed stage and mathematical model. As a result, we have succeeded in developing a fine-motion stage with longer strokes than ones driven by piezoelectric elements, though it is inferior in response. Positioning accuracy of the pneumatic-bellowdriven stage is ±5 [nm], which is tantamount to that achieved by piezoelectric elements.

Special Issue on Pneumatics for Innovative Machine Design

Pneumatics has greatly progressed as convenient multifunctional automation technology. One typical application is in compact light-weight highperformance pneumatic actuators. The introduction of control theory has also enabled useful pneumatic servosystems. New actuators include pneumatic artificial rubber muscles, which are small, light-weight, and soft. These are used for applications in the medical, welfare, and nursing fields. This special issue focuses on actuator development in drive-circuit analysis and design. Issues in these areas include pneumatic actuators, pneumatic rubber muscles, pneumatic circuit analysis and design, energy-saving, pneumatic servocontrol, advanced control systems, industrial applications, automation, vehicles, entertainment, medical, welfare and nursing applications, and education. This special 13-article issue is divided into (i) control design and pneumatic cylinder and bellows applications and (ii) the development and applications of soft pneumatic actuators. Some types of soft pneumatic actuators use artificial rubber muscles for welfare and rehabilitation equipment. This special issue should prove useful in understanding state-of-the-art of pneumatic technology applicable to analysis, design, control, and application in innovative machine design. I would like to express my sincere appreciation to all of the authors and reviewers for their invaluable effort.

TH-E-220-06: Selection of External Surrogate for 4DCT Sorting: Does It Impact Target Delineation?

Purpose: To evaluate differences observed between two different external surrogate acquisition systems: Varianˈs Real-Time Position Management (RPM) and Philips Medical Systems pneumatic bellows, in the context of 4DCT sorting and tumor delineation. Methods: Eight patient displacement curves from RPM data were inputted into the motion platform with a variety of amplitudes (0.5 to 3 cm). Simultaneous 4DCT acquisition was performed with both bellows and RPM block placed on the platform. The bellows signal was used for on-line retrospective phase-based sorting, while raw 4DCT data was reconstructed off-line using RPM signal on a research version of the Extended Brilliance Workspace (Philips Healthcare). Curves were resampled, normalized, and analyzed to determine the association between different external surrogates, amplitude differences, and latency between systems. 4DCT data was imported into Eclipse, and a lung window/level was used for all contouring. The volumes and centroids were compared among techniques. Results: Pearson r correlations between the RPM and bellows-acquired breathing traces were 0.987– 0.999. Slight discrepancies were observed with low amplitude displacement, where bellows were not as sensitive as RPM to slight variations in motion platform position. Target volumes were 200.27 +/− 12 cc and 199.96 +/− 13.3 cc for RPM and bellows targets, respectively, which was not significantly different (t(7) = 0.33, p = 0.75). Small centroid variations were observed between bellows and RPM contoured MIP targets: 0.025 +/− 0.05 mm, 0.013 +/− 0.04 mm, and 0.25 +/− 0.32 mm in lateral, anterior-posterior, and superior- inferior directions, respectively. Largest volume difference was observed for an RPM target 2.5 cc (1%) less than bellows target, which showed the largest difference in centroid displacement (0.9 mm). Overall, RPM data lagged behind the bellows data ∼126 ms. Conclusions: We have demonstrated comparable results between Philips bellows and Varianˈs RPM system, particularly in the management of 4D treatment planning. Acknowledgment: This work is supported in part by Philips Healthcare Conflict of interest: Henry Ford Health Systems holds a research agreement with Philips Healthcare.

WE‐D‐204B‐04: Distribution of Lung Tissue Motion during Free Breathing

Purpose: To characterize and quantify free breathing lung tissue motion diction. Method and Materials: 50 patient data sets were acquired using a 4DCT protocol consisting of 25 ciné scans at abutting couch positions on a 16 slice scanner. The tidal volume of each scan was measured by simultaneously acquiring spirometry and an abdominal pneumatic bellows. Because of the natural variation in breathing patterns, we elected to develop the concept of a representative breath. The representative breath was defined by first dividing the breathing traces into individual breaths, from exhalation to exhalation. A linear breathing drift model was assumed and the drift removed for each breath. Breaths that exceeded one standard deviation in period and amplitude were removed from the analysis. A representative breath was defined as the average time from peak inhalation to a normalized tidal volume. Airflow was determined using a sliding polynomial fit to the representative breath profile. The trajectories were computed using an existing 5D lung tissue trajectory model: X = Xo+αngr+βf where α and β were previously determined. In order to characterize the motion patterns, the elongation of the trajectories were examined throughout the subject's lungs. Elongation was defined here by generating a bounding box with one side parallel to the α vector and the box lying in the plane defined by the α and β vectors. Results: The representative breath process provided an excellent method for defining an average breath that had continuous tidal volume and airflow characteristics when the breath was continuously repeated. The elongation varied smoothly throughout the lungs. Left lung elongation was 0.10±0.05 and right lung elongation was 0.09±0.04 in a central coronal lung slice. Conclusion: As expected, motion elongations were relatively small indicating for many tumor sites, hysteresis motion could be ignored. This work supported in part by NIHR01CA116712 and NIHR01CA96679.

SU‐GG‐J‐90: Quantification of the Thorax‐To‐Abdomen Breathing Ratio for Breathing Motion Modeling

Purpose: To develop a methodology to quantitatively measure the thorax‐to‐abdomen breathing ratio for breathing motion modeling and breathing motion studies. Method and Materials: The breathing ratio was quantified by measuring the rate of body volume increase throughout the thorax and abdomen as a function of tidal volume. 15 16‐slice 4DCT patient image data sets from the neck through the pelvis were acquired during quiet respiration using a protocol that acquired 25 ciné scans at each couch position. Tidal volume was used as the breathing‐cycle surrogate, measured using a spirometer and abdominal pneumatic bellows. The volume within the skin contour at each CT slice was compared against the tidal volume, exhibiting a nearly linear relationship. A linear regression analysis was used to determine η(i), defined as the amount of expansion at each slice i per unit tidal volume. The sum Ση(i) throughout all slices was predicted to be the ratio of room air density to internal air density; 1.11. The boundary between the thorax and abdomen was determined by examining the patient anatomy and setting the boundary at the Xiphoid process. The thorax and abdomen regions were individually analyzed to determine the thorax‐to‐abdomen breathing ratios. Results: The average Ση(i) for all data sets was found to be 1.23±0.20, close to the expected value of 1.11. The thorax‐to‐abdomen breathing ratios were 0.22±0.19. The average Ση(i) was 0.20±0.13 in the thorax and 1.04±0.26 in the abdomen. The boundary between the thorax and abdomen was localized using a 50th tidal volume percentile reconstructed CT image. Conclusion: A method to quantify the relationship between abdomen and thoracic breathing was developed and validated. This work supported in part by NIHR01CA116712 and NIHR01CA96679.

Development of coarse/fine dual stage using pneumatically driven bellows actuator and cylinder with air bearings

Abstract In this paper, a coarse/fine dual positioning stage for single degree of freedom using pneumatic actuators is developed. The coarse movement utilizes a pneumatic cylinder with air bearings. The fine movement utilizes an actuator driven by pneumatic bellows. A high-performance pneumatic servo valve, we have developed, having high dynamics up to 300 Hz is used to control the coarse stage. The fine stage is controlled with a nozzle-flapper type servo valve. The fine stage is mounted on the coarse stage. As the proposed coarse/fine dual stage is pneumatically driven, the stage has advantages of low heat generation and non-magnetic those are suitable for ultra precise positioning. The control method of the dual stage is proposed. The experimental results demonstrated that the steady state error is less than 5 μm for 100 mm stroke with the coarse stage and it is minimize to 20 nm with the fine stage.

SU-FF-J-104: Feasibility of Utilizing Pneumatic Abdominal Bellows for Quantitative 4DCT

Purpose: To determine if a breathing surrogate can be utilized in place of a spirometer for quantifying 4DCT. Method and Materials: Using an established four dimensional computed tomography (4DCT) protocol, forty one patient data sets were acquired while measuring the breathing cycle using both spirometry and a pneumatic abdominal bellows. The image datasets were segmented to find the total lung volume (air content) and the bellows internal pressure signal was normalized into tidal volume for the entire scan session by correlating against the spirometry data subdivided into sequential 18.75 s periods. A threshold tolerance of 2% in the correlation of each 18.75s period was applied to ignore times where the spirometry apparatus leaked or failed to record meaningful data. This threshold provided a conservative criterion in identifying regions of abnormal spirometry response. The tidal volume was compared against the air content to validate the normalized bellows signal. Results: The 2% threshold correlation excluded the time period where the spirometry signal was unreliable. Overall, 86% of the time periods are within the 2% threshold, providing sufficient data to determine the relationship between tidal volume and air content. The measured ratio of air content to tidal volume was 1.11±0.08 for all patients. The theoretical value is 1.11 based on the air density differences between room air and air inside the lungs.Conclusion: The bellows and spirometry data correlated well when the spirometry apparatus was functioning properly. The ratio of air content to spirometry‐measured tidal volume was exactly that expected using the ratio of air densities inside and outside the lungs. These data support the use of a non‐spirometry method of breathing gating such as the pneumatic bellows as long as the entire lungs are scanned to provide the air content data. This work supported in part by NIHR01CA116712 and NIHR01CA96679.

Model-based evaluation of railway pneumatic suspensions

On classical passenger trains, the secondary suspension is commonly ensured by airsprings which are integrated in a pneumatic circuit. In addition to the pneumatic bellows, the circuit contains various pneumatic components such as tanks, pipes, orifices, levelling valves, etc., the purpose of the latter being to maintain a constant height between the carbody and the bogie. These elements can be connected in several ways leading to many existing suspension topologies. This paper deals with the multidisciplinary modelling of a vehicle equipped with such a suspension taking into account both multibody and pneumatic aspects. First, it depicts in more detail the various elements of a pneumatic suspension. Then, many criteria that influence the suspension morphology are presented: the kind of bogie, the use of an auxiliary tank, the position of this tank relative to the bellows, the kind of levelling system, the use of an additional anti-roll bar, the use of an additional hydraulic damper, etc. The description of the complete pneumatic circuit implies the use of thermodynamic models which take into account the airflow through the pipes and the valves, the pressure in the bellows, etc. Several pipe models are presented, the choice depending on the length of the pipe: an algebraic model is sufficient for short pipes, while a differential model is needed to take into account the dynamics of longer pipes. The pneumatic model is then coupled with a SIMPACK multibody model in order to analyse the behaviour of the complete vehicle. Two-point and four-point configurations are compared for Δ Q/Q and curve entry tests.

SU-GG-J-18: A Surface-Based Respiratory Surrogate for 4D Imaging

Purpose: Real‐time acquisition of three‐dimensional surface tracking has potential as an external surrogate for respiratory correlated CTimaging and radiation therapy. This study assesses the GateCT surfacetracking system (VisionRT, UK) by comparing real patient tracking and phantom imaging output to current surrogate systems.Method and Materials: Absolute tracking accuracy was tested using a 4D motion platform (Washington University, St. Louis) programmed with real‐patient respiratory trajectories. A cylindrical object was attached to the 4D phantom arm as a GateCT tracking surface. The optical RPM camerasystem (Varian Medical) and pneumatic bellows device were attached to the phantom arm for simultaneous monitoring of phantom motion. Respiratory traces from each of the three systems were compared against actual phantom motion. Next, a small sphere was placed on the phantom arm and the experiment was repeated while imaging in helical retrospective 4D mode. Three scans were acquired, each using a different surrogate system for reconstruction. All phases were reconstructed and the 0% and 50% phases were contoured. The centroid of each contoured volume was compared to the true phantom position. Finally, real patient respiratory tracking was performed simultaneously with the three systems on two volunteers. Respiratory traces from the three systems were compared for each volunteer to assess relative agreement between the waveforms. Results: Error for the three surrogate systems was < 0.5mm for phantom tracking. The GateCT system produced a root‐mean‐squared error of 0.6mm when tracking a moving surface during imaging. Additionally, the position of the contoured sphere on reconstructed 0% and 50% GateCT scans differed by < 0.3mm from scans performed with the other surrogate devices. Respiratory traces from human subjects closely correlated. Conclusion: The GateCT system produces comparable results to other surrogate devices and may offer additional advantages with its topography based acquisition method.

The OmniTread OT‐4 serpentine robot—design and performance

AbstractSerpentine robots are slender, multi‐segmented vehicles designed to provide greater mobility than conventional mobile robots. Serpentine robots are ideally suited for urban search and rescue, military intelligence gathering, and inspection tasks in hazardous or inaccessible environments. One such serpentine robot, developed at the University of Michigan, is the “OmniTread OT‐4.” The OT‐4 comprises seven segments, which are linked to each other by six joints. The OT‐4 can climb over obstacles that are much higher than the robot itself, propel itself inside pipes of different diameters, and traverse difficult terrain, such as rocks or the rubble of a collapsed structure. The foremost and unique design characteristic of the OT‐4 is the use of pneumatic bellows to actuate the joints. The pneumatic bellows allow the simultaneous control of position and stiffness for each joint. Controllable stiffness is important in serpentine robots, which require stiff joints to cross gaps and compliant joints to conform to rough terrain for effective propulsion. Another unique feature of the OmniTread design is the coverage of all four sides of each segment with drive tracks. This design makes the robot indifferent to rollovers, which are bound to happen when the slender bodies of serpentine robots travel over rugged terrain. This paper describes the OmniTread concept and some of its technical features in some detail. In the Experiment Results Section, photographs of successful obstacle traverses illustrate the abilities of the OT‐4. © 2007 Wiley Periodicals, Inc.

An Adaptive Approach to Decomposing Patient-Motion Tracking Data Acquired During Cardiac SPECT Imaging

Patient motion during cardiac SPECT imaging can cause diagnostic imaging artifacts. We have implemented a Neural Network (NN) approach to decompose monitored patient motion data, gathered during cardiac SPECT imaging, using the Polaris stereo-IR real-time motion-tracking system. Herein, we show the successful decomposition of Polaris motion data into rigid body motion (RBM) and respiratory motion (RM). The motivation for separating RM from RBM is that each is corrected using different methods. The NN requires the input of a RBM threshold sensitivity limit, as well as the median filter window width. A two step approach can be used in setting the median filter width. In the 1(st) NN run the median filter window width is initially set to a "fixed" width typical of the respiration period. This 1(st) NN run does an initial decomposition of the data into RM and RBM. The RM is then fed into an FFT algorithm to produce a respiratory period output file for use during a 2(nd) NN run, where the median filter width can "adapt" to the patient respiratory rate at each time point. Implementation of the NN was in the UNIX environment with Interactive Data Language (IDL). Decomposition of simulated "signals known exactly" RBM and RM resulted in average value errors less than 0.11 mm for RBM steps, and an overall root mean square error of only 0.3 mm for RM or RBM. Volunteer RBM and RM Polaris data were successfully decomposed by the NN with RBM steps resolved with an average difference of only 0.8 mm as compared to values displayed on the SPECT gantry console which are only to the nearest mm. A plot of the NN RM trace and the synchronized trace from a pneumatic bellows shows virtually identical characteristics. Anthropomorphic phantom RBM and RM were decomposed and used to correct motion in SPECT images during reconstruction. The motion corrected slices looked visually identical to slices acquired without motion, and comparison of slice count profiles further confirmed the correction.

Inchworm-Like Colonoscopic Robot with Hollow Body and Steering Device

Unskillful operation and rough handling of conventional colonoscope, especially at the sigmoid colon, may lead to perforation or splitting the colon wall. Thus, it is crucial to develop autonomous or semi-autonomous colonoscopes that do not require physical force by the doctors for their motions. In this paper, we report the design and development of a colonoscopic robot system that has a locomotive function based on inchworm-like motion, with a hollow body and a steering system that consists of three pneumatic bellows of 7mm diameter, each located 120 ◦ apart from the others at the head part. The steering device can bend up to approximately 90 ◦ . In order to evaluatethe performance of the colonoscopic robot, in-vitro tests and in-vivo tests were carried out. The experimental results show the feasibility of the prototype colonoscopic robot being used for diagnosis and treatments in colon.

Integrated Joint Actuator for Serpentine Robots

Serpentine also sometimes called snake robots, are slender, multisegmented vehicles designed to provide greater mobility than conventional wheeled or tracked robots. Serpentine robots are typically comprised of three or more rigid segments connected by two or three degrees of freedom joints. The segments typically have powered wheels, tracks, or legs to propel the vehicle forward; the joints may be powered or unpowered. We have developed a joint actuator system that is highly optimized for use in serpentine robots. This article first presents an analysis of the particular requirements for joint actuators in serpentine robots. We then compare existing actuators against those requirements and show that pneumatic bellows are ideally suited for this application. Following this analysis, this paper introduces our fully functional, pneumatically operated actuation system that is efficiently in the space occupied by a joint. This system, which we call an integrated joint actuator, also allows simultaneous proportional control of position and stiffness of the joint. The key advantages of our design over other joint actuation methods are its great strength combined with controllable compliance and minimal space requirements.