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International audience; The generalized rigid registration problem in high-dimensional Euclidean spaces is studied. The loss function is minimized with an equivalent error formulation by the Cayley formula. The closed-form linear least-square solution to such a problem is derived which generates the registration covariances, i.e., uncertainty information of rotation and translation, providing quite accurate probabilistic descriptions. Simulation results indicate the correctness of the proposed method and also present its efficiency on computation-time consumption, compared with previous algorithms using singular value decomposition (SVD) and linear matrix inequality (LMI). The proposed scheme is then applied to an interpolation problem on the special Euclidean group SE(n) with covariance-preserving functionality. Finally, experiments on covariance-aided Lidar mapping show practical superiority in robotic navigation.

The problem of calibrating extrinsic parameter between camera and inertial measurement unit (IMU) using an industrial robotic manipulator has been studied. This generates a result of hand-eye/robot-world/camera-IMU calibration in a simultaneous fashion. The developed method is free of inertial integration over time and thus is robust to uncertain IMU biases. It is derived that the problem can be solved via a simultaneous optimization of hand-eye/robot-world/camera-IMU transformations. The resulted optimization is highly non-convex on the special Euclidean group and we give globally optimal solutions. Experiments verify that the proposed method is capable of estimating accurate calibration parameters. Comparative studies between representatives show the global optimality of the proposed method. The new simultaneous method is capable of conducting calibration of a robot/camera/IMU combination. The designed method guarantees the global optimality thus the accuracy is ensured. The developed globally optimal solutions will also be computationally efcient on modern industrial computers. Finally, we show that the proposed method can give accurate calibration results for a stereo/IMU sensor combination.

This paper deals with the simultaneous estimation of the attitude, position and linear velocity for vision-aided inertial navigation systems. We propose a nonlinear observer on $SO(3)\times \mathbb{R}^{15}$ relying on body-frame acceleration, angular velocity and (stereo or monocular) bearing measurements of some landmarks that are constant and known in the inertial frame. Unlike the existing local Kalman-type observers, our proposed nonlinear observer guarantees almost global asymptotic stability and local exponential stability. A detailed uniform observability analysis has been conducted and sufficient conditions are derived. Moreover, a hybrid version of the proposed observer is provided to handle the intermittent nature of the measurements in practical applications. Simulation and experimental results are provided to illustrate the effectiveness of the proposed state observer., Accepted for publication in IEEE Transaction on Automatic Control. 16 pages, 6 figures

We report an improved air spacer (AS) integration scheme to overcome problems with the conventional AS process. The new scheme is fully compatible with other emerging CMOS technology elements such as self-aligned contact (SAC) and contact over active gate (COAG). Using a fan-out3 (FO3) ring oscillator (RO) on a 10-nm FinFET platform, we experimentally demonstrate that the new AS provides 15% reduction in the effective capacitance ( ${C}_{{\text {eff}}}{)}$ . Such a ${C}_{{\text {eff}}}$ reduction translates to 21% performance gain at the constant power (iso-power) or 36% power reduction at the constant performance (iso-speed). The benefits provided by AS exceed the benefits of a full CMOS node scaling from 7 to 5 nm. Clearly, AS is a viable technological element for continuing CMOS scaling.

Conventional methods formulate the calibration problem between a robot hand and a camera, also known as hand–eye-calibration problem, as AX = XB . However, in practice, these methods have limited accuracy, as will be shown in our experimental results. In this article, we formulated the hand–eye calibration problem as a point-set-matching problem and proposed a new approach to solve this problem. The proposed approach is particularly suitable for robotic applications and offers good accuracy. We obtain a solution for the said problem using the gradient-descent (GD) technique on the special Euclidean group SE(3). We call this approach GD-SE(3). To prove the validity of the proposed approach and to demonstrate its advantages, experimental results are provided, where we compare the performance of GD-SE(3) with both conventional solutions for the hand–eye calibration problem as well as those based on point-set matching. The results show that the accuracy of GD-SE(3) is comparable with those based on other point-set-matching algorithms. Yet, it outperforms conventional formulations based on AX = XB while offering a more suitable approach for the hand–eye calibration problem of robot manipulators.

We give a universal analytical solution to the hand-eye calibration problem ${AX} = {XB}$ with known matrices ${A}$ and ${B}$ and unknown variable ${X}$ , all in the set of special Euclidean group SE(3). The developed method relies on the 4-D Procrustes analysis. A unit-octonion representation is proposed for the first time to solve such a Procrustes problem through which an optimal closed-form eigendecomposition solution is derived. By virtue of such a solution, the uncertainty description of ${X}$ , being a sophisticated problem previously, can be solved in a simpler manner. The proposed approach is then verified using simulations and real-world experimentations on an industrial robotic arm. The results indicate that it owns better accuracy and better description of uncertainty and consumes much less computation time.

This paper deals with the design of globally exponentially stable invariant observers on the Special Euclidian group $SE(3)$ . First, we propose a generic hybrid estimation scheme (depending on a generic potential function) evolving on $SE(3)\times \mathbb {R}^6$ for pose (orientation and position) and velocity-bias estimation. Thereafter, the proposed estimation scheme is formulated explicitly in terms of inertial vectors and landmark measurements. Interestingly, the proposed estimation scheme leads to a decoupled rotational error dynamics from the translational dynamics, which is an interesting feature in practical applications with noisy measurements and disturbances.

Yield uncertainty widely exists in manufacturing industries. Because of the particularities of the recovery and production processes, remanufacturing is seriously affected by the uncertainty of the production process, which also affects the remanufacturing choice of enterprises. In this paper, we focus on the case where a make-to-order type manufacturer is confronted with the strategic option of obtaining core materials by self-remanufacturing or outsourcing new cores. Through a stochastic modelling approach, a two-echelon closed-loop supply chain is constructed to capture the manufacturer's sourcing strategy and production planning by considering yield uncertainty in both the remanufacturing and production stages. We first examine the case of a deterministic recovery rate. The results show that regardless of whether the firm chooses to remanufacture or buy new core materials, the expected profit of the (re)manufacturer is always concave. Then, in the case of a random recovery rate, we show that the distribution bounds are important and play key roles in deciding the strategic option of self-remanufacturing or outsourcing. By comparing the upper and lower bounds of the recovery rate with the procurement cost of new raw material and used product, three production/sourcing strategies, namely, using remanufactured cores only, outsourcing new material only and jointly using the two materials, are investigated. The optimal procurement quantity and the optimal production input are derived to maximize the (re)manufacturer's expected profits under the three scenarios. Finally, we perform sensitivity analysis of the impact of yield uncertainty on the optimal results. The results show that when the shortage cost increases, the collection quantity increases faster than the production input, which implies that a “bullwhip effect” exists in the proposed two-period collection and production system. The conclusions of this paper can be applied to remanufacturing in related enterprises to provide production and procurement decision support for managers and to promote the efficiency of closed-loop supply chains.

An ultrafast (10- $\mu \text{s}$ delay) measurement technique is used to characterize the negative bias temperature instability-induced threshold voltage shift ( $\Delta {V}_{T}$ ) in replacement metal gate-based high-K metal gate Si and SiGe p-FinFETs. The dc stress-recovery $\Delta {V}_{T}$ time kinetics, voltage acceleration factor (VAF), and temperature activation energy ( ${E}_{A}$ ) are compared for different germanium percentages (Ge%) in the channel and nitrogen percentages (N%) in the gate-stack. A comprehensive physical model framework based on uncorrelated contributions from the generation of interface ( $\Delta {V}_{\mathrm {IT}}$ ) and bulk oxide ( $\Delta {V}_{\mathrm {OT}}$ ) traps and hole trapping in preexisting defects ( $\Delta {V}_{\mathrm {HT}}$ ) is used to explain the measured data. The impact of Ge% and N% on $\Delta {V}_{T}$ , VAF, ${E}_{A}$ , temperature (T) dependence of VAF, and stress bias ( ${V}_{\mathrm {GSTR}}$ ) dependence of ${E}_{A}$ are quantified. The interface trap generation component is independently verified by direct-current ${I}$ – ${V}$ (DCIV) measurements.

An ultrafast (10- $\mu \text{s}$ delay) measurement technique is used to characterize ac negative-bias temperature instability-induced threshold voltage shift ( $\Delta \text {V}_\text {T}$ ) in replacement metal-gate-based high-K metal gate Si and SiGe p-FinFETs. Time kinetics of stress and recovery, voltage acceleration factor, temperature activation energy ( $\text {E}_\text {A}$ ), frequency (f), and pulse duty cycle (PDC) dependence are shown for different germanium percentages (Ge%) in the channel and nitrogen percentages (N%) in the gate insulator. A comprehensive physical model framework based on uncorrelated contributions from interface ( $\Delta \text {V}_\text {IT}$ ) and bulk oxide ( $\Delta \text {V}_\text {OT}$ ) trap generation and hole trapping in preexisting defects ( $\Delta \text {V}_\text {HT}$ ) is used to explain the measured data at different stress biases ( $\text {V}_\text {GSTR}$ ), temperatures (T), f, and PDCs. Direct-current I–V measurements are used to independently verify the interface-trap generation component for ac stress. End-of-life degradation for different processes under dc and ac conditions is estimated by using the calibrated model and compared to predictions from conventional analytical methods.

Spectral and polarimetric contents of the light reflected from an object contain useful information on material type and surface characteristics of the object. Jointly exploiting spatial, spectral, and polarimetric information helps detect camouflage targets. Motivated by the vision mechanism of some known aquatic insects, we construct a bioinspired multiband polarimetric imaging system using a camera array, which simultaneously captures multiple images of different spectral bands and polarimetric angles. But the disparity between the fixed positions of each component camera leads to the loss of information in the boundary region and a reduction in the field of view (FOV). In order to overcome the limits, this paper presents a deep learning method for FOV expansion, incorporating the gradient prior of the image into a nine-dimensional convolutional neural network's framework to learn end-to-end mapping between the incomplete images and the FOV-expanded images. With FOV expansion, the proposed model recovers significant missing information. For the problem of insufficient training data, we construct the training dataset and propose the corresponding training methods to achieve good convergence of the network. We also provide some experimental results to validate its state-of-the-art performance of FOV expansion.

Several special reliability features for Hf-based high-/spl kappa/ gate dielectrics are highlighted, including: 1) trapping-induced threshold voltage (V/sub th/) shift is much more of a concern than TDDB in determining the operating lifetime; 2) n-channel MOSFETs (nMOSFETs) are more vulnerable than p-channel MOSFETs (pMOSFETs); and 3) MOSFETs with polySi gates are more vulnerable than those with metal gates. These will be discussed in the context of existing electron/hole traps and trap generation by high-field stress. A novel technique to probe traps in ultrathin gate dielectrics, inelastic electron tunneling spectroscopy (IETS), will be shown to be capable of revealing the energies and locations of traps in high-/spl kappa/ gate dielectrics.

FinFETs provide a path for continued pitch and voltage scaling because of their excellent electrostatic short channel control. The key to design and optimization of FinFET technologies is to understand the differences of their reliability characteristics from those of planar devices. In this letter, we elucidate the differences in positive-bias temperature instability (PBTI) reliability between silicon-on-insulator nFinFETs and planar-bulk nFETs through experiments and TCAD modeling. We show that significantly improved PBTI for FinFET over planar-bulk at a given operating voltage arises from reduced vertical field. Furthermore, we show that the reduced field in FinFETs stems from less depletion charge in strong inversion associated with a fully depleted structure.

We demonstrate the device performance benefit of Cu contact over W contact using high-κ/metal gate CMOS devices. The ring oscillator (RO) device of Cu contact showed reduction in external resistance, which resulted in an increase in drive current by 5% for both nFET and pFET devices. The delay on the gate-cap-loaded RO improved by 5%-7% with Cu contact. We evaluated device reliability tests for gate dielectric breakdown, positive-bias temperature instability, negative-bias temperature instability, and hot carrier injection on 32- and 22-nm-node devices with Cu contact. The reliability results for the Cu contacts with the reliable barrier layer and good gap fill are comparable to those of W contacts.