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Purpose To determine whether children and adults with unilateral congenital upper limb amputation can control myoelectric prostheses with multiple degrees of freedom (DOF) using pattern recognition (PR) technology. Methods Seven participants (age 9–62 years) with unilateral congenital transradial amputation were tested on both their residual and sound side limbs to determine proficiency in controlling a virtual prosthesis using electromyographic signals captured by an array of surface electrodes that were processed using PR technology. Proficiency was measured through a virtual environment game called the target achievement control test, in which the testing protocol asked participants to match increasingly complex prosthesis postures with 1, 2, and 3 DOF. Results All the participants successfully created a PR calibration at 1, 2, and 3 DOF with their residual limb during testing, and no differences in calibration accuracy were observed when comparing the residual versus sound upper limbs. No differences were noted in the mean completion rate on the target achievement control test between the residual and sound limbs. Conclusions Participants with a congenital upper limb amputation achieved PR control calibration of multi-DOF prostheses with proficiency and quality results of PR calibration that were comparable to those of their sound limb. This capability was observed in children as well as in adults. This demonstrates the potential for children and adults with a unilateral congenital transradial amputation to benefit from myoelectric prostheses with PR control. Clinical relevance The results from this study highlight the potential for patients in this population to benefit from myoelectric prostheses with PR control. Persons with unilateral congenital upper limb amputations can be considered for provision of this technology and enrollment in future research activities.

Objectives The aim of the present study was to examine whether movement contingent sensory effects could be used to prime and facilitate motor performance on a ball-tossing task. Design The ball-tossing task was performed across two consecutive days, and consisted of an acquisition phase and a test phase. During the acquisition phase, participants ( N = 30) practiced an underhanded ball tossing task to a near and far target ( N = 360 total, n = 180 each distance). Tosses that landed near the target immediately produced an auditory feedback tone upon landing, with unique tones for both the near and far target. In the test phase, the auditory tones preceded the toss and served as imperative stimuli for the tossing task. Method The test phase consisted of three tossing conditions (corresponding, non-corresponding, and control) in which the participants responded to the tones by tossing the ball to either the corresponding or non-corresponding target associated with the tones during learning. Results Findings indicated that both accuracy and consistency of ball tossing improved when the toss was preceded by the corresponding auditory feedback associated with the successful execution of the action during learning. Conclusions The present study extends previous research by showing that complex actions consisting of multiple degrees of freedom can be primed via movement contingent sensory effects. Furthermore, this study demonstrates that movement-effect priming can impact distal measures of motor performance (e.g., accuracy of tossing), as opposed to the features of movement production (e.g., response selection, initiation, and execution).

Inspired by common patterns of biological movement, a series of near-infrared (NIR) laser-driven bionic intelligent hydrogel actuators were successfully fabricated via the combination of infiltration method (entirety infiltration and locality infiltration), structure design and material characteristics. The controllable distribution of graphene oxide (GO) particles in a hydrogel matrix resulting from the infiltration method led to abundant bionic deformations with multiple degrees of freedom and flexibility. In addition to the highest response speed of 187.7°/s, the hydrogel actuators underwent accurate and repeatable static deformations and efficient and stabilized dynamic locomotion, demonstrated, for example, through the assembly of origami, the deformation of fingers and palm, the closing and blooming of a chrysanthemum and the crawling of an inchworm. This study opens a new path for practical bionic applications of NIR-triggered hydrogel actuators in self-assembly biosensor, targeted drug delivery and minimally invasive surgery.

Origami, also known as paper folding, has shown its potential to construct 3D structures from designed crease patterns on a flat sheet. This paper proposes a method to design axisymmetric 3D origami with generic six-crease bases. Inspired by the conventional six-crease bases, i.e., waterbomb base or Yoshimura base, where six regular crease lines meet at an interior vertex, we generalize the generic base so that the lengths of the crease lines can be regular or irregular. This method is based on designing the crease patterns. First, we interactively generate a crease pattern consisting of such generic bases. Then, our method analytically calculates the 3D origami shape with an axisymmetric structure. We demonstrate various configurations, i.e., sets of input parameters, to explore the variations of the calculated 3D origami. The 3D origami can have multiple degrees of freedom, but by continually changing one parameter we present a motion that can axisymmetrically deploy or flatten the shape. The method for designing 3D origami has potential applications ranging from self-folding tessellations to deployable architectures.

Humans perform a variety of feedback adjustments to maintain balance during walking. These include lateral footfall placement, and center of pressure adjustment under the stance foot, to stabilize lateral balance. A less appreciated possibility would be to steer for balance like a bicycle, whose front wheel may be turned toward the direction of a lean to capture the center of mass. Humans could potentially combine steering with other strategies to distribute balance adjustments across multiple degrees of freedom. We tested whether human balance can theoretically benefit from steering, and experimentally tested for evidence of steering for balance. We first developed a simple dynamic walking model, which shows that bipedal walking may indeed be stabilized through steering—externally rotating the foot about vertical toward the direction of lateral lean for each footfall—governed by linear feedback control. Moreover, least effort (mean-square control torque) is required if steering is combined with lateral foot placement. If humans use such control, footfall variability should show a statistical coupling between external rotation with lateral placement. We therefore examined the spontaneous fluctuations of hundreds of strides of normal overground walking in healthy adults (N = 26). We found significant coupling (P = 9·10−8), of 0.54 rad of external rotation per meter of lateral foot deviation. Successive footfalls showed a weaker, negative correlation with each other, similar to how a bicycle’s steering adjustment made for balance must be followed by gradual corrections to resume the original travel direction. Steering may be one of multiple strategies to stabilize balance during walking.

A method for performing modal analysis of undamped active flexible multibody systems with collocated sensors and actuators in a finite element environment was recently developed by the authors. In this paper, the theory is further expanded to include systems with non-collocated sensors and actuators, damping and steady-state error elimination. The closed-loop eigenvalue problem for active flexible multibody systems with multiple-input multiple-output proportional-integral-derivative (PID) feedback type controllers and multiple degrees of freedom finite element models is solved.

A new cascade control of multiple degrees of freedom program based on modified internal model control is proposed for chemical and industrial cascade processes. Because the set-point tracking and disturbance rejection in the secondary control loop exercise influence on performance of primary loop simultaneously, they are decoupled completely and can be adjusted independently. A disturbance observer is added in the primary loop which realizes the decoupling control between set-point tracking and disturbance rejection, and there is no tradeoff any more. Simple and effective analytical method is adopted to devise the controllers. Finally, simulations example demonstrates the validity of the proposed control scheme.

This paper proposes a novel approach for nonlinearity detection in vibrating systems. The approach is developed based on a new concept recently proposed by the author known as nonlinear output frequency response functions (NOFRFs) and the properties of the NOFRFs for nonlinear systems with multiple degrees of freedom (mdof). The results of numerical simulation studies verify the effectiveness of the approach. Nonlinear components often represent faults in practical mdof systems including beams. The proposed approach therefore has significant potential in the fault diagnosis of practical mdof engineering systems and structures.

In this paper, we report a prototype of a new pivot bearing having three degrees of freedom. The idea of the pivot bearing is based on a constant velocity joint (CVJ). In the first report, two types of pivot bearing were designed and produced. Then, the static performance was examined. In this second paper, we have achieved three degrees of freedom by adding a ball bearing mechanism. However, this bearing with three degrees of freedom was larger than the bearing with two degrees of freedom. Then, in order to improve the internal structure, a full complement ball bearing was applied. Thus, the size of the bearing with three degrees of freedom was conformed to the bearing with two degrees of freedom. Furthermore, process accuracy was evaluated.

This paper deals with the examination of specifications to improve the performance of a pivot bearing with two degrees of freedom by finite element method (FEM). As the target of estimation for performance of the bearing, we evaluated the contact pressure and the stiffness. As the results of FEM considering the number of grooves and the contact angle of the planetary ball, a large effect was obtained in the case that the number of rows of planetary balls was 2. The effect was confirmed by measuring axial displacement.

In a previous article (Ref. [R. Glowinski, L.J. Shiau, Y.M. Kuo, G. Nasser, The numerical simulation of friction constrained motions (I): One degree of freedom models, Applied Mathematics Letters 17 (2004) 801–807]) the authors discussed the application of operator-splitting methods to the time-discretization of those mathematical relations describing the behavior of elasto-dynamical systems with friction, focusing on one-degree of freedom models. The main goal of the present article is to generalize the methodology discussed in Ref. [R. Glowinski, L.J. Shiau, Y.M. Kuo, G. Nasser, The numerical simulation of friction constrained motions (I): One degree of freedom models, Applied Mathematics Letters 17 (2004) 801–807]; there are no conceptual difficulties in doing so, the main issue being the computation of a vector-valued multiplier modeling the friction forces (or part of them). An iterative method allowing the computation of this multiplier will be discussed and the results of numerical experiments will be presented.

A new microassembly technique has been developed to combine polymer micro-objects fabricated by stereophotolithography with shape memory alloy (SMA) wires. This technique is based on a local laser-aided potymerization allowing SMA wires to be associated with polymer structures. Since stereophotolithography allows the fabrication of real three-dimensional objects, different mechanical structures have been designed and manufactured to develop miniaturized mechanical devices (in the centimetre range) with multiple degrees of freedom actuated by SMA wires (diameter 120 µm). The actuation principle has been successfully tested. Experimental measurement procedure and results are presented and discussed. Further developments and improvements of the actuators are proposed.

A method to estimate the standard deviation of eigenvalue and eigenvector of random multiple degrees of freedom (MDOF) systems is presented. This method can be applied not only to the MDOF systems with distinct eigenvalues, but also to the systems with multiple eigenvalue. Results for a beam and a truss are presented.

A heretofore neglected application of Markov theory to define a general formalism for the analysis of NMR relaxation data on systems with multiple internal motions is proposed. It is noted that the theory predicts a modified lorentzian line shape for systems not at equilibrium.

A general numerical integration procedure for the calculation of dynamic response to impulsive loads is presented. The procedure is completely developed for a single-degree-of-freedom system and extended to systems with multiple degrees of freedom. Numerical examples are given in which a comparison is made between approximate and exact solutions. The accuracy obtained is well within acceptable limits for most applications.