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For tasks in robotic assembly, a basic requirement is the capability of the robotic system to detect contacts with the environment. While this information can readily be obtained from dedicated force-torque sensors, it might either be technically difficult to mount such sensors or too expensive to do so. In this paper, an alternative approach is presented which reconstructs the external forces and...
The estimation of mutual information between graphs has been an elusive problem until the formulation of graph matching in terms of manifold alignment. Then, graphs are mapped to multi-dimensional sets of points through structural preserving embeddings. Point-wise alignment algorithms can be exploited in this context to re-cast graph matching in terms of point matching. Unfortunately, the potentially...
In order for a prosthesis to restore power generation during cycling, it must supply torque in a manner that is coordinated with the motion of the bicycle crank. This paper outlines an algorithm for the real time estimation of the angular position of a bicycle crankshaft using only measurements internal to an intelligent knee and ankle prosthesis. The algorithm assumes that the rider/prosthesis/bicycle...
This paper describes a preliminary study of using four inertial measurement units (IMUs) attached to the heel and pelvis to estimate the joint angles of normal subjects during walking. The IMU, consisting of a 3-D accelerometer and gyroscope, is used to estimate the planar displacement of the heel and pelvis and the angular change of heel in one gait cycle. We then model the gait as a planar 3R serial...
This paper presents a novel estimation method for extracting the activation rate of the human leg muscles using the recursive least squares algorithm. It is shown that the output force of each leg muscle group can be simply estimated from the reconstructed real measurement data. The estimation result turned out to be fairly comparable to those from electromyography, yet much simpler and faster. Considering...
A novel instrumentation is proposed to estimate hand and finger movements. Current dataglove systems often measure a reduced set of joint angles and lack a position and orientation measure of the hand with respect to the trunk. Our proposed system, based on inertial and magnetic sensing, is fully ambulatory, light weighted, has a low energy consumption and is therefore suitable to assess kinematics...
Within this manuscript a novel technique for joint Digital Elevation Model (DEM) reconstruction and deformation estimation is presented. In particular, a Maximum A Posteriori (MAP) estimator that makes use of Gaussian Markov Random Fields (MRF) is proposed. The advantage of the approach, with respect to classical Permanent Scatterers (PS) based techniques, consists of its ability to evaluate the height...
This paper presents an adaptive scheme in overcoming signal distortion, caused by I/Q imbalance and multipath propagation, in an OFDM receiver. Estimation of I/Q imbalance and channel parameters is performed in the frequency domain with the aid of pilot tones. These estimated values are then used to adjust the gain and phase to reduce the distortion caused by I/Q imbalance. The resulting less distorted...
In this research, we propose a methodology for getting joint angles by Kinect sensor for rehabilitation evaluation support. We measure the motion of the arm of a patient with hemiplegia before and after the rehabilitation, and estimate the range of the motion by using genetic algorithm and neural network. The range after the rehabilitation is bigger than before the rehabilitation. Based on this result,...
A novel vectorized method for the estimation of direction of arrival (DOA) and frequency of arrival (FOA) is presented in this paper for the uniform linear array (ULA). Firstly, a vectorized data form is employed to estimate the DOAs and FOAs at the same time. Then, based on the subspace methodology, the DOAs and FOAs can be matched quickly. By using orthogonal projection, the accuracy of the parameters...
Representing the reception condition directly, both Signal-to-noise ratio (SNR) and Doppler shift are important parameters in mobile channels, and therefore are widely used in system performance evaluations and adaptive applications. Accordingly, this paper investigates a frequency domain iterative estimator for SNR and Doppler shift in mobile communications, where the discrete cosine transform (DCT)...
In this paper, we propose a high-precision digital framework to compensate for non-ideal effects in the analog front-end circuits for wireless communication systems. The IQ imbalance and the carrier frequency offset (CFO) are jointly estimated with a band-selective mechanism of the orthogonal frequency division multiplexing (OFDM) system. The compensable CFO range is four times wider than prior schemes...
This paper presents a nonlinear estimation algorithm which utilizes a low-degree of freedom model of functional electrical stimulation (FES) and orthosis-based walking to estimate lower-limb angles. The estimated lower limb angles can be used to decide when the FES signal should be applied to the leg during the different phases of walking. To this end, we use measurements from inertial measurement...
We present an approach for the joint probabilistic estimation of pedestrian head and body orientation in the context of intelligent vehicles. For both, head and body, we convert the output of a set of orientation-specific detectors into a full (continuous) probability density function. The parts are localized with a pictorial structure approach which balances part-based detector output with spatial...
In this paper we propose an adaptive controller based on sliding mode and backstepping approaches. The system to be controlled is an exoskeleton used for the rehabilitation of the knee joint. The person wearing the exoskeleton is healthy, sitting and performs movements of flexion/extension. This kind of movement is usually applied by the doctor. The parameters of the dynamic model of the overall system...
Cooperative communication systems employ cooperation among nodes in a wireless network to increase data throughput and robustness to signal fading. However, such advantages are only possible if there exist perfect synchronization among all nodes. Impairments like channel multipath, time varying phase noise (PHN) and carrier frequency offset (CFO) result in the loss of synchronization and diversity...
For the emerging 60GHz millimeter-wave communications, the nonlinearity is usually inevitable due to RF power amplifiers operating in the ultra-high frequency and enormous bandwidth, which, in collusion with frequency-selective propagations, poses great challenges to signal detections. In contrast to classical schemes calibrating nonlinear distortions in transmitters, a blind detection algorithm is...
We present a method for real-time bare hand tracking that utilizes natural hand synergies to reduce the complexity and improve the plausibility of the hand posture estimation. The hand pose and posture are estimated by fitting a virtual hand model to the 3D point cloud obtained from a Kinect camera using an inverse kinematics approach. We use real human hand movements captured with a Vicon motion...
Wearable motion tracking systems represent a breakthrough in ecological motion tracking. Their effectiveness has been proved in many fields, from performance assessment to human-robot interaction. Most of the approaches are based on the exploitation of optimal probabilistic filtering of inertial motion units (IMUs) signals, ranging from linear Kalman Filters (KF) to Particle filters (PF). Since most...
This paper addresses ego-motion noise suppression for a robot. Many methods use motion information such as position, velocity and acceleration of each joint to infer ego-motion noise. However, such inference is not reliable since motion information and ego-motion noise are not at all times correlated. We propose a new framework for ego-motion noise suppression based on single channel processing without...
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