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A human-inspired hand-over control strategy is proposed for the haptic interaction of two dual-fingered hands for the planar case. It is based on a grasp controller for an unknown object which achieves, via fingertip rolling, a stable grasp and a real object mass estimation. Object load transfer is receiver initiated, follows human evidence and involves awareness of the other hand's state based solely...
Robust fingertip force detection from fingernail image is a critical strategy that can be applied in many areas. However, prior research fixed many variables that influence the finger color change. This paper analyzes the effect of the finger joint on the force detection in order to deal with the constrained finger position setting. A force estimator method is designed: a model to predict the fingertip...
A novel Kalman filter to estimate the center of mass (COM) of a Humanoid robot is proposed. In the conventional works, COM was estimated by some methods. First one is the kinematics computation based on the mass property of the robot and the global position and attitude of the body frame, but those errors degrade the estimation accuracy. Second is the double integral of COM acceleration computed by...
Lack of dexterous control over the position of a catheter's distal tip and not having any feedback from the quality of tip - tissue contact are among the factors that make the conventional catheter-based method of performing cardiac ablation very challenging. To resolve these issues, in this paper, we present a robotic catheter manipulation system that accommodates a conventional ablation catheter,...
Surface electromyography (sEMG) signals have been extensively studied in the area of intention detection, force estimation and control of rehabilitation devices. Studies regarding sEMG based jaw muscle force estimation are necessary towards building intuitive neural-controlled soft oral rehabilitation robot (SORR). This paper presents a force estimation algorithm based on masseter muscle sEMG signals...
This work presents a novel haptic device to study human grasp, which integrates different technological solutions thus enabling, for the first time, to achieve: (i) a complete grasp characterization in terms of contact forces and moments; (ii) an estimation of contact point location for varying-orientation contact surfaces; (iii) a compensation of force/torque offsets and estimation of the mass and...
In this study, a novel method for estimating wrist forces from surface electromyogram (EMG) measured from the upper limb is proposed, which can be applied for unilateral transradial amputees. Three degrees of freedom (DoFs) of wrist including flexion-extension, abduction-adduction, and pronation-supination were used. We first classify feature vectors extracted from the EMG signals into three classes...
Vehicle yaw moment of inertia is an important parameter for many vehicle dynamic models and control systems yet it is usually difficult to estimate. A methodology in estimating the vehicle yaw moment of inertia is presented in this article by studying the linear relationship between vehicle lateral acceleration, yaw acceleration, and rear wheel lateral tire forces. This linear relationship is derived...
In this paper, individual muscular forces of the lower limb are estimated in real-time by inverse dynamics-based static optimization with a wearable sensor system. The wearable sensor system consists of inertial measurement units (IMUs) and manually developed ground reaction force (GRF) sensors. Joint torques of the lower limb during walking are calculated in real-time by applying inverse dynamics...
In this paper, the analysis of sensor failure and corresponding fault tolerant control method for mechanical electric parking brake system was proposed, the estimation model for tilt sensor was built. The simulation model and PID controller was constructed based on Matlab. The hardware in the loop simulation platform was built with the AutoBox as a system control unit. The system control strategy...
In this paper, the conception and optimization of a new dual-stage haptic device is described. A particular attention is given to the choice of encoder. Compact, consumer grade, but low resolution encoders are particularly used. An issue arising from this particularity is the deterioration of the velocity measurement when Finite Difference method is used. Moreover, when encoders resolution decreases,...
Parameter estimation plays a key role in describing a dynamical system behavior accurately. Thus, the inverse problems to identify the parameter values which characterize the dynamical system have attracted much attention from the engineering field in recent years. The Lankarani-Nikravesh (L-N) contact force model, which is proven to be more consistent with the physics of contact, is employed to describe...
Inverse dynamics analysis, which enables the information about joint force/torque of human body from the measured motion data, is a traditional tool in biomechanical studies. Conventionally, measurements of body motion are obtained by motion capture cameras, of which the bulkiness and high cost make it hard to capture some movements that need broad range of space. As an alternative, inertial motion...
This paper presents a novel integrated optimal dynamics control of 4WS4WD electric vehicles via hierarchical control methodology. In the higher-level design, an LQR controller is proposed to obtain the generalized longitudinal force, lateral force and yaw moment, according to their respective reference values. In the lower-level design, the control signals from the higher-level controller are allocated...
The aim of this work is to improve the safety and control robustness of robots interacting physically with humans by enhancing their contact perception. More specifically in the abdominal area, respiratory motions are clearly influencing the contact dynamics but have not yet been accounted for in the estimation of the contact impedance. We propose here a combined mechanical-respiratory model of impedance...
Power factor in mechanical system is a new concept to express characteristic in mechanical system. It defines dynamic behavior of the impedance characteristic in the motion. However, conventional derivation method requires short-time Fourier transformation in order to consider random input in mechanical system as a combination of sinusoidal waves. This paper proposes a novel method to obtain power...
This paper reports the results of the UNIZG-FER team in the third European Robotics Challenge (EuRoC). More precisely, the results of the 1st qualifying stage of the challenge where a micro aerial vehicle (MAV) is tested in realistic simulation scenarios. The paper presents the entire controller setup, starting from the power distribution level, low level cascade controllers with wind disturbance...
Perceptually adaptive sampling based on Weber's law has been used to reduce the haptic packet rate for efficient haptic data transmission over Internet. In a teleoperation, perceptually significant force samples are transmitted from a robot to a human operator. If the time spacing between two consecutive perceptually sampled kinesthetic force stimuli is less than the minimum time spacing (temporal...
We present a new edge-preserving image smoothing approach by incorporating local features into a holistic optimization framework. Our method embodies a gradient constraint to enforce detail eliminating and an intensity constraint to achieve shape maintaining. The gradients of high-contrast details are suppressed to a lower magnitude, subsequent to which structural edges can be located. The intensities...
The computation of skin forces and deformations for tactile rendering requires an accurate model of the extremely nonlinear behavior of the skin. In this work, we investigate the characterization of finger mechanics with the goal of designing accurate nonlinear models for tactile rendering. First, we describe a measurement setup that enables the acquisition of contact force and contact area in the...
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