Programmable Motion Research Articles

2820 力制御を利用したプログラマブルCPMの開発(S60-1 健康・福祉機器の開発(1),S60 健康・福祉機器の開発)

We have developed the programmable Continuous Passive Motion device (CPM) to achieve the treatment with effective load reduction by following to the position of the knee rotation center axis and load sensor feedback to the motion. In order to raise a healing effect more, we produced the new CPM. In this paper, we describe the constitution of new CPM and the comparison results between the single axis control and the five axis control.

Validation of the path integration of 4D dose distributions with 4D phantom measurements

4D treatment planning generates a series of 3D dose distributions to represent the motion properties of the patient and/or radiation delivery system. The purpose of this study is to validate with 4D phantom measurements the use of the 3D optical flow method algorithm for the numerical path integration of 4D dose distribution data into a single 3D dose distribution. The Radiological Physics Center (RPC) thoracic phantom was placed on a programmable motion table to simulate respiratory motion. 4D CT imaging was performed on a multi-slice CT scanner (Philips Medical Systems, Anhover, MA). The CT data was binned into eight phases. The CT images were sent to a Pinnacle workstation (version 6.2b, Phillips Medical Systems, Anhover, MA) where a treatment plan was designed on the end expiration image set. The treatment plan was transposed onto the other respiratory phases and a 4D dose data set generated. The plan was delivered using a Varian 2100 linear accelerator (Varian Medical System, Palo Alto, CA). The dose delivered to the RPC thoracic phantom was recorded using radiographic film and thermoluminescent dosimeters for calibration. The 3D optical flow method (3D OFM) algorithm is a deformable image registration algorithm we have implemented. 3D OFM was used to calculate the displacement fields between the respiratory phases. The displacement fields were used to map the dose distributions from the multiple respiratory phases onto the end expiration phase. The resulting dose distributions were summed with equal weighting, performing numerical path integration. The calculated and measured dose distributions were compared with the static plan. The attached figure illustrates the dose distributions. A coronal section through the static treatment plan is shown in figure A.u1/2pick;3197f1;0;11 The 3D OFM algorithm was applied and numerical path integration performed on the 4D dose distribution data resulting in a single 3D dose distribution. The corresponding coronal section is shown in figure B. A coronal section through the measured dose distribution is shown in figure C. The delivered dose distribution had a peak width at 90% maximum of 38.5 mm. The corresponding value for the path integrated 4D plan and the end expiration static plan were 42.6 mm and 47.0 mm. The 50% isodose line was displaced 0.5 mm when compared with the path integrated 4D plan and 8.6 mm when compared with the end expiration static plan. The 3D OFM algorithm provides the displacement field necessary for numerical path integration to map a 4D dose distribution data set into a single 3D dose distribution accurately. The resulting dose distribution was found to more closely represent the delivered dose versus the static plan for a moving phantom.

Programmable motion and patterning of molecules on solid surfaces.

Adsorbed on a solid surface, a molecule can migrate and carry an electric dipole moment. A nonuniform electric field can direct the motion of the molecule. A collection of the same molecules may aggregate into a monolayer island on the solid surface. Place such molecules on a dielectric substrate surface, beneath which an array of electrodes is buried. By varying the voltages of the electrodes individually, it is possible to program molecular patterning, direct an island to move in a desired trajectory, or merge several islands into a larger one. The dexterity may lead to new technologies, such as reconfigurable molecular patterning and programmable molecular cars. This paper develops a phase field model to simulate the molecular motion and patterning under the combined actions of dipole moments, intermolecular forces, entropy, and electrodes.

Zugkraftmessungen beim knöchernen Segmenttransport – in vivo Untersuchungen am Menschen / Tractive Force Measurement in Bone Transport – an in vivo Investigation in Humans

Bone transport applying the principle of distraction osteogenesis makes it possible to reconstruct long bone defects caused by trauma or resection of bone tumors. The method employing a central cable, developed in Munich, is especially suitable for such applications. The main bone fragments are stabilized by an external fixateur, and bone transport is effected with a single central cable fixed to the tip of the segment, and driven by an external, programmable motor. In 15 patients the tractive forces during the entire bone transport were measured with a strain gauge incorporated within the cable. On the basis of the force profiles characteristics normal bone transport (forces between 150 - 250 N) can be distinguished from a critical transport (forces > 250 N) with the risk of premature consolidation. There is some evidence that at a very high level of force, just before premature consolidation a very effective form of bone transport with good bone neoformation can be achieved. Transport systems employing a central cable allow this special form of distraction osteogenesis, since there is continuous force monitoring, and there is the option of employing the traction force as a control factor in a loop.

An innovative, programmable architecture for ultra-low power motion estimation in reduced memory MPEG-4 encoder

This paper describes an ultra-low power, cache based, and programmable motion estimator with memory reduction for MPEG-4 video encoding. It exploits a low complexity motion estimation algorithm, achieving a quality comparable or superior to the full search approach with only 1% of the computation and the power consumption.

Drive-Control System for the TACTIC Gamma-Ray Telescope

A PC-based drive-control system has been developed for the altitude-azimuth mounted TACTIC γ-ray telescope to control the speed and direction of motion of its 2-axes. Details of various hardware components chosen for the telescope, including hybrid-stepper motor, 16-bit absolute encoder and CAMAC-based programmable stepper motor controller, are discussed in this paper. The telescope-control strategy, based on the position-loop with a proportional type control for the source-seek mode and the on/off type control for the tracking mode, is explained in detail. Some important performance features of the telescope, including its blind-spot size, drive-system backlash and encoder-error compensation, are also presented. The drive system has been extensively field-tested and has been operating satisfactorily during observation campaigns carried out since March 1997 with the TACTIC Imaging Element. A tracking accuracy of ±3 arc-minutes has been achieved. A test report of its performance, with regard to its tracking accuracy on the basis of successful detection of TeV γ-rays from the active galaxy Markarian 501 in April–May 1997, is also presented.

A system to simulate gas exchange in humans to control quality of metabolic measurements.

We have developed a gas exchange simulation system (GESS) to assess the quality control in measurements of metabolic gas exchange. The GESS simulates human breathing from rest to maximal exercise. It approximates breath-by-breath waveforms, ventilatory output, gas concentrations, temperature and humidity during inspiration and expiration. A programmable motion control driving two syringes allows the ventilation to be set at any tidal volume (VT), respiratory frequency (f), flow waveform and period of inspiration and expiration. The GESS was tested at various combinations of VT (0.5-2.51) and f(10-60 stroke x min(-1)) and at various fractional concentrations of expired oxygen (0.1294-0.1795); and carbon dioxide (0.0210-0.0690) for a pre-set flow waveform and for expired gases at the same temperature and humidity as room air. Expired gases were collected in a polyethylene bag for measurement of volume and gas concentrations. Accuracy was assessed by calculating the absolute and relative errors on parameters (error=measured-predicted). The overall error in the gas exchange values averaged less than 2% for oxygen uptake and carbon dioxide output, which is within the accuracy of the Douglas bag method.

Improved system for sonographic imaging and biometry of the cornea.

We developed a programmable motion system for high-frequency (50 MHz) ultrasonographic imaging of the cornea. The system permits a variety of scanning modes, including arc scans matched to the approximate radius of curvature of the cornea. This approach allows high-precision biometry (+ or - 2 microm) over a much larger region of the cornea than the 3 mm central zone obtainable with conventional rectilinear scanning. Using 60 degree wide meridional arc scans covering each clock-hour of a rabbit cornea, we obtained data over an 8 mm wide central zone and produced maps representing the thickness of the corneal epithelium.

A 14-Gops programmable motion estimator for H.26X video coding

A 14 Giga operations per second (Gops) programmable motion estimator chip is developed to support multiple algorithms and video coding standards. The chip performs multisurvivor motion estimation in the subsampled scan and the cluster search mode. The chip uses a dual-addressing single-port memory and a pel-rotating processing element array to implement synchronous self-aligned block difference computation. The chip is implemented in 0.5-/spl mu/m CMOS achieving 86.4 Million operations per second (Mops)/KXtr and 21 mW/Gop. The chip delivers full search quality for H.26X coding at CIF 30 f/s, near full search quality at NTSC level, and a wide range of other video quality and resolution tradeoffs.

Digital Motion Control and Profile Planning for Pneumatic Servos

This paper considers the use of “profile-planning” to (i) improve/optimize certain performance characteristics of pneumatic servos and (ii) simplify procedures associated with their tuning. The underlying approach is to preplan the transient behavior of the system thereby generating an appropriate command profile. To assist in applying this technique to the control of air-powered servo-systems, the paper highlights important knowledge derived previously with regard to the stability and operating characteristics of pneumatic drives. Preliminary rules for conducting such planning are then proposed with reference to a series of experimental observations. This approach can be employed to significantly reduce or prevent overshoot and instability of servo-driven pneumatic actuators (cylinders in particular) which are difficult to overcome by using conventional methods. At the same time, increased operating speeds and improved positioning can be attained. The proposed control scheme has been implemented in prototype form through using a proprietary programmable motion controller which incorporates software mechanism for generating gearbox and cam-like motion profiles.

Robots: future key elements in laboratory automation

Robots as freely programmable motion and control devices are likely to become a key element in laboratory automation. An example for a successful application is PillPack, a flexible blister packaging system for clinical studies. The primary requirements when developing the system were production accuracy approaching 100% and flexibility comparable to manual packing. The solution to the problem was a handling robot with integrated vision. The vision system is used to continuously check the handling process. The application software with graphical user interface provides extensive safeguards against operator errors. It allows easy mouse-driven programming of new blister shapes and loading patterns. The resulting short set-up time makes processing small lot sizes economical.

Single chip CD decoder

A highly integrated compact disc (CD) decoder is described. The chip contains all the decoding functions, digital filtering, bit-stream stereo digital-to-analog (D/A) conversion, and analog post-filtering. The design makes use of a CMOS process that results in its having a single 5-V supply, an extended operating temperature range, and low power consumption to make the IC suitable for portable and inexpensive applications. The chip contains circuitry for CD-decoding, programmable motor control, digital filtering, microcomputer interfacing, and switch capacitor network for stereo right and left channels. The 80-pin QFP packaged IC can withstand an extended temperature range of -40 degrees C to +85 degrees C.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

LIDIA: large isotope dilution ion-probe analyses

A new analytical technique for trace element analysis has been developed based on isotope dilution and on the use of an ion probe. It allows the determination of concentrations at the ppm level with a precision of a few percent. The chemical procedure involves dissolution, spiking of the sample and separation of groups of trace elements. The samples are subsequently loaded on a silicon substrate, and a programmable motion of the sample holder in the ion probe allows a routine analysis of around 80 loads per “run”, which corresponds to 15 elemental concentrations (REE, Li, K, Rb, Sr, Ba) on 10 different samples. Various parameters influencing the precision of the technique have been tested. The precision and the swiftness of the technique have allowed us to easily test its reproducibility. From a sample of tholeiitic basalt, split in ten fractions after dissolution, the total variation of the concentrations are ±1.5% for Sr, 2% for the REE, 4% for Ba and Rb, and 10% for Li.

Wind tunnel facility for operation at very low velocity

An apparatus for conducting small-scale wind tunnel experiments is described, in which extension of the usual lower velocity range is derived from use of a reticulated metal resistance in the working section and a programmable microstepping motor.

Optimal Actuator Sizing for Robotic Manipulators Based on Local Dynamic Criteria

Robotic manipulators provide general, programmable motion paths and force functions to carry out processes of a high level of dexterity and flexibility. These systems are characterized by several degrees of freedom of controllable motion. As a consequence the resulting mechanical structure contains a very large number of design values including geometric, mass, compliance, strength, and prime mover parameters [1]. The analysis on which to base the design methods involves the multivariable mathematical relations between these design parameters and the manipulator’s force and motion states which are extraordinarily complex, nonlinear, and highly coupled. Computer-aided procedures for systems of this class become an imperative in order to establish the dynamic formulation, select rational design specifications, and to evaluate the system’s operating characteristics both locally and globally. This paper suggests some applications of optimization techniques to augment the existing analysis formulation in the literature and to create a more powerful foundation for the design of manipulator structures. This enhanced computational capability is based on position-dependent kinematic and modeling coefficients [6] which explicitly demonstrate the role of significant physical parameters in the design process. Specific examples dealing with optimal distribution of actuator load capacity are given in the paper which improves the system’s load capacity or enhances its speed and acceleration capability within the local neighborhood of a given configuration of the manipulator.