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Extending leg length in a biped entity may improve some gait factors such as speed, worsening some others. This study is undertaken to better understand the kinetic and kinematic aspects of human gait following changes in the geometry of lower extremities. An artificial structure is built to be attached and fixed to one's leg. Using a two-sensor motion capture system practical walking data with the...
The kinematic performance optimization of a 2-PRR parallel robot based on new variance indices is given in this paper. First, the inverse kinematic equation of the 2-PRR parallel robot is derived. Then the velocity performance evaluable indices LCI and GCI, the stiffness performance evaluable indices LSI and GSI are analyzed. To consider the distribution of the LCI and LSI in the global indices, two...
Recently haptic devices are increasingly used in industry and research. As their applications become widespread, their design is needed to be more efficient. At design stage, determinant features of haptic devices such as rigidity, force bandwidth, accuracy etc. must be considered and improved. Structurally, parallel mechanisms (PMs) are appropriate candidates for haptic devices. Due to multi legged...
To acquire a better understanding of how individuals adapt to knee osteoarthritis (KOA) and assess the effect of TKA, 3D gait analysis was conducted 17 pre-TKA KOA patients, 10 post-TKA KOA patients and 12 age-matched control subjects. Principle component analysis was used to extract waveform characteristics. Improved function was observed after TKA, but the overall lower limb capacity of post-TKA...
Stroke patients have reduced kinematic characteristics in gait speed, cadence, step kinematics, and range of motion (ROM). Especially, a drop foot is a common symptom during gait after stroke due to the weakness of ankle dorsiflexor. A few robotic ankle systems have been developed to measure and train pathological ankle movements. However, the previously developed systems use orthogonal ankle axis...
The design of lever amplification mechanism plays the crucial rule in the performance of double-feet piezoelectric linear motor which is based on the lever amplification principle. The kinematic principle of double-feet piezoelectric linear motor based on the lever amplification mechanism was analyzed and the dynamic model of the lever amplification mechanism based on the flexure hinge was established...
This paper investigates the problem of employing reconfigurable robots in an underwater setting. The main results presented is the experimental validation of a modelling methodology for a system consisting of N dynamically connected robots with heterogeneous dynamics. Two distinct types of experiments are performed, a series of hydrostatic free-decay tests and a series of open-loop trajectory tests...
Lofstrand, or forearm, crutches are a common assistive mobility device for those with functional impairments. However, repeated loading of the wrist and palmar region and continual hyperextension of the wrist during Lofstrand crutch usage may cause wrist strain, pain, and secondary injuries such as carpal tunnel syndrome. In order to reduce risk of injury, a novel wrist orthosis was developed with...
Robot technology is increasingly widely applied in medical field for rehabilitation, especially for the paralysis of stroke patients. In this paper, a new design concept of upper limb rehabilitation robot has been developed. The model is expected to perform three degrees of freedom that is rotation in horizontal and vertical planes. This system is of advantages in terms of light weight, dexterity...
This paper developed a self-adaptive robotic hand with novel flexible fingers of multiple passive joints, called MPJ hand, whose main mechanism is based on the linkage-style parallel and self-adaptive finger in SARAH Hand, can perform parallel pinching grasp and self-adaptive encompassing grasping modes with relatively even force distribution. A MPJ hand is developed with three MPJ fingers and 45...
This paper reports on a conceptual design for a modular XYZ micro/nano-positioning stage by employing bridge amplified flexure mechanism and piezoelectric actuators. The mechanism design and analysis of a new terse parallel flexure stage with three translational degrees-of-freedom (DOF) is presented. The FEA simulation of dynamics analysis and fatigue analysis are conducted to reveal the capacity...
In this paper, a teleoperation approach is developed for TouchX device using wave variable technique. The control system employs the 6-DOF (degrees of freedom) Geomagic® TouchX as a master device, and a 2-DOF simulated robot manipulator as slave. The master device provides user haptic feedback such that the bilateral opreation can be achieved for the teleoperation system. To avoid singularity pose...
People with physical impairments often have asymmetric gait. To evaluate if their overall symmetry is improving during intervention, there needs to be a simple metric that can help classify gait patterns that includes multiple measures of gait asymmetry. The Combined Gait Asymmetry Metric presented here is based on the Mahalanobis distance of multiple step parameters. We tested able-bodied subjects...
Paper presents application of called factitious force method and experiments results using the real mobile skid-steering mobile platform. Due to fact that lateral slippage is needed for changing the orientation, constraints for this phenomena cannot be introduced to the system and, thus, the mobile platform is underactuated on dynamics level. Control problem can be solved by expanding relevant components...
In the article the whole process of a manipulator controller development is presented. The controller is designed for the execution of various benchmark tasks in the field of service robotics. Initially, a set of system behaviors is presented as the base of the universal controller structure. For that purpose the embodied agent theory and the System Modeling Language are utilized. The execution and...
To determine a force-closure grasp, current grasp synthesis algorithms either assume a deterministic model to compute a desired finger placement without noise, or model the end-effector position as a free-floating rigid body whose noise in pose is independent of the kinematic chain formed by the robot arm. In this work we instead explore a probabilistic approach that explicitly models noise in joint-angles...
This paper presents a systematic method to build the kinematic model and dynamic model of a nonholonomic wheeled mobile robot (WMR) with longitudinal and lateral slip, followed by the design of a control law using the input-output feedback linearization method to drive the mobile robot to track a given trajectory while longitudinal, and lateral slip exist. The asymptotical stability of the system...
The basic kinematic features of the magnetoplastic effect in the nonmagnetic crystals established on the base of experimental and theoretical studies combined with the computer simulations are presented. The dislocation motion through a random distribution of point defects under the simultaneous action of the mechanical stress and the magnetic field is discussed. It was proved that the magnetic field...
This paper presents the optimization of muscle forces in the human upper extremity for the desired trajectory. The proposed kinematic model of the human upper extremity is a force redundant mechanism, implying that number of actuators are more than number of outputs. During the trajectory, the torque is generated for each joint by antagonistic activation of muscles. The biological actuators (muscles)...
The past decade has seen great progress in the development of adaptive, low-complexity, underactuated robot hands. An advantage of these hands is that they use under-constrained mechanisms and compliance, which facilitate grasping even under significant object pose uncertainties. However, for many minimal contact grasps such as precision fingertip grasps, these hands tend to move the object after...
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