Search

This paper describes a vacuum suction-type end effector for depalletizing robots in distribution centers. The developed end effector has multiple suction pad units to which a bellows pneumatic actuator is applied as the support mechanism. Load-bearing capacity is improved due to a high-strength wire provided inside the bellows, and the contraction force is improved due to ring members placed inside of the ridges of the rubber bellows. The developed end effector is attached to the arm of a linear motion-type depalletizing robot, and its real-world performance is verified. Verification results confirm that the suction pad units tolerate cardboard box inclination and differences in box height by a simple lowering motion of the arm, and multiple cardboard boxes can be simultaneously unloaded. Moreover, as compared with conventional end effectors, the developed end effector achieves large expansion and contraction in a thin structure. The developed end effector is expected to broaden applications for depalletizing robots.

Deep learning has been widely used for inferring robust grasps. Although human-labeled RGB-D datasets were initially used to learn grasp configurations, preparation of this kind of large dataset is expensive. To address this problem, images were generated by a physical simulator, and a physically inspired model (e.g., a contact model between a suction vacuum cup and object) was used as a grasp quality evaluation metric to annotate the synthesized images. However, this kind of contact model is complicated and requires parameter identification by experiments to ensure real world performance. In addition, previous studies have not considered manipulator reachability such as when a grasp configuration with high grasp quality is unable to reach the target due to collisions or the physical limitations of the robot. In this study, we propose an intuitive geometric analytic-based grasp quality evaluation metric. We further incorporate a reachability evaluation metric. We annotate the pixel-wise grasp quality and reachability by the proposed evaluation metric on synthesized images in a simulator to train an auto-encoder--decoder called suction graspability U-Net++ (SG-U-Net++). Experiment results show that our intuitive grasp quality evaluation metric is competitive with a physically-inspired metric. Learning the reachability helps to reduce motion planning computation time by removing obviously unreachable candidates. The system achieves an overall picking speed of 560 PPH (pieces per hour)., Comment: 18 pages, 2 tables, 7 figures

Bin-picking of small parcels and other textureless planar-faced objects is a common task at warehouses. A general color image&ndash, based vision-guided robot picking system requires feature extraction and goal image preparation of various objects. However, feature extraction for goal image matching is difficult for textureless objects. Further, prior preparation of huge numbers of goal images is impractical at a warehouse. In this paper, we propose a novel depth image&ndash, based vision-guided robot bin-picking system for textureless planar-faced objects. Our method uses a deep convolutional neural network (DCNN) model that is trained on 15,000 annotated depth images synthetically generated in a physics simulator to directly predict grasp points without object segmentation. Unlike previous studies that predicted grasp points for a robot suction hand with only one vacuum cup, our DCNN also predicts optimal grasp patterns for a hand with two vacuum cups (left cup on, right cup on, or both cups on). Further, we propose a surface feature descriptor to extract surface features (center position and normal) and refine the predicted grasp point position, removing the need for texture features for vision-guided robot control and sim-to-real modification for DCNN model training. Experimental results demonstrate the efficiency of our system, namely that a robot with 7 degrees of freedom can pick randomly posed textureless boxes in a cluttered environment with a 97.5% success rate at speeds exceeding 1000 pieces per hour.

Transverse-flux motors basically have coils wound in the rotational direction and armature cores surrounding them. This configuration allows the motors to be designed for multipole structures with the simple coil geometry independent of the pole number. Therefore, they have an advantage on high-torque generation over most motors having windings wound around teeth and put in slots. However, transverse-flux motors still have a production problem for their multipole rotor due to the assembly of the small and numerous permanent magnets. Thus, we have designed a consequent-pole transverse-flux motor, having a half amount of magnets on the rotor compared with the conventional surface-mounted magnet rotors, and capable of generating almost the same torque under the same size and excitation conditions. However, this motor also has large cogging torque due to the consequent poles, having deformed magnetomotive-force distribution. Thus, we propose a new skewed core structure for reducing the cogging torque, compatible to axially non-uniform structure of this motor. The Finite Element Method analysis result indicates the peak-to-peak value of the cogging torque that can reduce by 82% with this proposed skewed structure.

The partial response and maximum likelihood (PRML) detection method is promising as a detection scheme for next-generation optical disk systems. For application of the PRML detection, a new value is required in order to evaluate signal quality instead of jitter, which is used in current optical disk systems. For this requirement, we developed a new evaluation method that is based on the principle of the PRML detection. This evaluation value is defined as the occurrence probability of miss-detection in the PRML detection. We evaluated the proposed method using a simulated waveform and an experimental waveform for two systems. Each system consists of a phase change disk with cover layer thickness of 0.6 mm and 0.1 mm, a blue laser with wavelength of 409 nm and 407 nm and an objective lens with numerical aperture of 0.65 and 0.85, respectively. As a result, we confirmed the validity of the proposed method for each system.

The partial response and maximum likelihood (PRML) signal processing method is effective for fabricating high-density optical disks because it allows inter-symbol interference in decoding. However, some deterioration factors, namely impulse response fluctuations and signal level fluctuations, still exist even though PRML signal processing is adopted. A combined adaptive controlled PRML signal processing method is proposed to surmount the problem of these two deterioration factors simultaneously. The key points of the combined adaptive controlled PRML signal processing are that the gain of the Viterbi decoder is unity and the expected signal takes into account the reference levels controlled in the adaptive controlled Viterbi decoder. The effectiveness of such processing is confirmed using simulated reproduced signals and actual reproduced signals. The characteristics in terms of the tangential tilt of the disk and the signal asymmetry are ameliorated by adopting the combined adaptive controlled PRML signal processing method.

We attempted to improve phase change media to achieve larger capacity for systems with blue lasers using numerical apertures (NA) of both 0.85 and 0.65. It was found that the Bi-added GeTe-rich pseudo-binary composition promised high erase ratio even when we did not use any interface layers on a recording layer. The use of an absorption control layer (ACL) was also attempted to suppress the cross erase (XE). It was found that the ACL was very effective in suppressing the XE. The advanced phase change media that used the above novel technologies showed good analog performance. The advanced media also showed bER of less than 1.0×10-4, promising 18 GB capacity for an NA of 0.65 and 30 GB capacity for an NA of 0.85.

A new write shift compensation method is proposed in this paper. The method is suitable for an optical disk system which adopts partial response maximum likelihood (PRML) detection, and it can optimize adaptive controlled writing pulses even under severe inter-symbol interference (ISI) conditions to reduce detection errors. This advantage is attributable to the use of the Euclidean distance as the estimation index of the mark edge shift error. The effect is confirmed by the experimental results for blue laser systems.

A novel holographic data storage (HDS) system with dual-reference beam is proposed. Several servo techniques that construct a read and write procedure of the HDS system are introduced and experimentally confirmed.

We have developed phase change media of 20GB capacity for the system with the numerical aperture of 0.65 and light incidence on 0.6 mm-thick substrate.

The combined adaptive controlled PRML signal processing was newly developed. The new method is a combination of the adaptive controlled FIR filter and the adaptive controlled Viterbi decoder. The adaptive controlled Viterbi decoder was operated under the condition that the Viterbi decoder is controlled such that the unity gain is kept. We report the simulation results, which are evaluated using signal asymmetry margin and tangential tilt margin to verify the effectiveness of this method expanding the margins. The combined adaptive controlled PRML signal processor is effective for these signal tolerances. Furthermore, the experimental results confirm the simulated effectiveness for expanding the tangential tilt margin. Consequently, a new method of combined adaptive controlled PRML signal processing is effective in reducing the deteriorations of data detection for high-density optical disk.

Advanced phase change medium of over 30GB data capacity has been proposed and the recording characteristics of the medium have been described. The medium has L-H polarity, Bi-substituted GeTe-rich pseudo-binary alloy film as the recording layer, and thin metal absorption control layer. The recording measurement was carried out by using a blue laser light source with the wavelength of 405nm and an objective lens with NA of 0.85. Both CNR and ER have been improved by the use of the Bi-substituted GeTe-rich composition. XE has been reduced by the use of the absorption control layer. The bER measurement demonstrated its capability for over 30GB data capacity.

A new write shift compensation method modified for optical disk systems to which PRML detection is applied is developed. The compensation method achieves optimization of all writing pulses adaptively. The compensation parameters are calculated to minimize the probability of detection errors. The experimental results certify that the ch.bER is improved using this method.

The partial response and maximum likelihood (PRML) method is promising as the detection scheme for next-generation optical disk systems. PRML detection requires a new value to evaluate signal quality instead of jitter, which is used in the current optical disk systems. For this requirement, some evaluation methods have been proposed. However, any evaluation methods for practical use has not been reported. In this paper, we propose a new method to evaluate the signal quality for systems to which PRML detection is applied. We compare the evaluation value of the proposal method with measured channel bit error rate (bER), and confirmed the validity of the new method.

In an effort to achieve as high a storage capacity as possible on a disc format that is similar to conventional DVD using blue-violet laser, a number of new technologies have been implemented for the phase change rewritable media. The technologies include the ways to meet challenges in obtaining larger signal amplitude for shorter bit lengths and lowering the cross erase for narrower track pitches. Technologies developed for both the single layer and the dual layer discs are discussed.

The possibility of an optical disk capacity of 28GB/side is studied. The read-write characteristics of a phase-change optical disk are examined using a thin cover layer, a blue laser diode, high NA objective lens and the PRML method. The wide tilt margins of high-density recording are achieved.

We propose a physical address format suitable for the separated guide layer of a multilayered optical disc. Since the track format of the guide layer is different from that of conventional multilayered discs, a novel address format is required. The proposed format adopts a land-and-groove-track structure to generate a stable tracking signal. The address information for land and groove tracks is physically premastered by the wobbling and width-modulating of grooves. We fabricated a replicated disc sample with the proposed format and demonstrated a sufficiently low bit error rate by an experiment. Consequently, we considered that the format is a promising solution for the physical format for multilayered discs with a separated guide layer.

Photopolymers are widely used as media for holographic data storage because of their high dynamic range, high photosensitivity and availability. However, the most photopolymers have a large coefficient of linear thermal expansion. Therefore, it is known that the temperature changes cause deterioration of readout image under the Bragg-mismatch conditions. This paper proposes a new servo algorithm which includes both the servo error signals detection method and the automatic compensation procedures with feedback servo for the holographic data storage system. Experimental results for the proposed technique are demonstrated for temperature changes of up to +25 K successfully.

Transscaphoid perilunate fracture dislocation and perilunate dislocation are the two major patterns of carpal dislocation. Their common feature is a dislocation of the head of the capitate from the distal surface of the lunate. However, isolated dislocation of the whole capitate is rare. A review of the literature noted only one case of capitate dislocation. 1 A case of rotatory subluxation of the capitate is presented. The injury was caused by the direct force on the dorsum of the wrist. Case Report A 37-year-old factory worker sustained a crush injury of the left hand and forearm in a rolling press. On physical examination, the left wrist and forearm were grossly swollen. There was not an obvious laceration of the skin. X-rays showed both dorsal dislocation of the carpometacarpal (CMC) joint and rotational subluxation of the capitate at the lunocapitate (LC) joint (Fig. 1). The left distal radioulnar joint was dislocated, with fractures of the styloid process of both the radius and ulna. The left wrist was surgically exposed via a dorsal incision. The proximal carpal row and the radiocarpal joint were intact. The capitate was subluxed at the LC joint, and the hamate and metacarpals were dorsal to the capitate. These findings confirmed the x-ray appearance. The operative findings were con

The spot size has been measured by chopping the beam spot with a knife edge on an optical disk. Tangential and radial spot sizes are measured with different two angled knife edges: θ1-edge and θ2-edge. In this paper, the errors in the measurement of spot sizes caused by the error in the scanning angle and the scanning velocity are described. The result of the theoretical analysis gives the best combinations of the scanning angles which are θ1=0°, θ2=±45° with the radial direction. For example, if the angle error of θ1 and θ2 obtained experimentally 0.64°, then the calculated error of the radial spot size is 2.2%. The analyzed error shows a good agreement with the experimental results. It was analytically observed that the influence of the scanning velocity error on the error of the measured spot sizes can be practically ignored using this method.