Torque Range Research Articles

Fatigability And Steadiness Of The Trunk Flexor Muscles In Young, Healthy Adults

The abdominal muscles are the prime movers for flexion of the trunk and are essential to several functional tasks, such as lifting. Improper function of the abdominal muscles has been linked with multiple impairments, including low back pain, incontinence and breathing dysfunction; however, measurements of fatigability and steadiness for this muscle group have not been reported. PURPOSE: To determine fatigability and torque fluctuations (steadiness) across a range of torques during isometric trunk flexion contractions in young, healthy adults. METHODS: Men (n=3) and women (n=8) (18-45 yrs) performed isometric trunk flexion tasks in a back flexion/extension attachment. Fatigability was assessed in upright sitting with an intermittent isometric protocol using 6 s contractions at 50% of maximal voluntary contraction (MVC), each followed by a 4 s rest period until task failure. MVCs were performed every 60 s. Task failure was defined as an inability to maintain the 50% submaximal contraction for 3 of 6 s or MVC ≤ 50% initial MVC. In a separate testing session, participants performed two trials of a 6 s isometric trunk flexion contraction at 5%, 10%, 20%, and 70% MVC. Steadiness was quantified as the amplitude of torque fluctuations and calculated as the standard deviation (SD) of torque and coefficient of variation (CV) for each contraction. RESULTS: Time to task failure for the trunk flexion intermittent submaximal fatigue task was 17.0 min. The SD of torque increased as contraction intensity increased. CV of torque declined with contraction intensity and was highest for the low intensity contractions (14.5% and 11.1% for 5% and 10% MVC, respectively) and lowest for the high intensity contractions (6.3% for 20% MVC and 3.3% for 70% MVC). CONCLUSIONS: The abdominal muscles demonstrated greater CV of torques than typically observed for the upper and lower limb (Jesunathadas et al, J Appl Physiol 112: 1897-1905, 2012) but the pattern of change with increased intensity was similar. Fatigability for an intermittent submaximal fatiguing trunk flexion contraction was similar to that for the elbow flexor muscles (Hunter et al, J Appl Physiol 96: 2125 - 2132, 2004) but less than for handgrip muscles (Hunter et al, Muscle Nerve 39: 42-53, 2009) in young, healthy adults.

Variable Recruitment of Parallel Elastic Elements: Series–Parallel Elastic Actuators (SPEA) With Dephased Mutilated Gears

The development and control of variable stiffness actuators (VSAs) led to the capability of embodying physical principles of safety and energy-efficiency compared to traditional stiff servomotors. However, the output torque range and efficiency of servomotors and VSAs are still insufficient which hinders the development of machines with performances comparable to a human. We have developed a novel compliant actuation concept, series-parallel elastic actuation (SPEA), that addresses these problems. The novelty being the variable recruitment of parallel elastic elements and adaptive load cancellation. In this paper, we propose the use of multiple dephased mutilated gears with locking ring and plate, as intermittent mechanisms, linked in parallel to the motor. As a result, the motor torque requirements can be lowered, as such the motor can be downscaled and the efficiency can be drastically increased. After an abstract description of the SPEA concept and an outline of the biological basis, we present the first unidirectional SPEA proof of concept (PoC) setup. Experiments on this PoC setup endorse the feasibility of the SPEA concept. The results match the modeled trend of a lowered motor torque and increased energy efficiency.

Comparison of an induction machine with both conventionally distributed and fractional-slot concentrated stator windings

The desired high energy conversion efficiencies over a complete operating torque and speed range combined with the recent increase in cost of rare-earth magnets have brought forth a renewed interest in the induction machine (IM) as a possible alternative to the rare-earth permanent magnet (PM) machine. Fractional-slot concentrated windings (FSCWs) allow significant cost reduction of a machine by reducing copper volume and manufacturing time. However, this type of winding is generally discussed in the context of brushless PM machines. The higher harmonic content of FSCWs is generally understood to be a significant drawback for such designs. We aim to substantiate this understanding by comparing the performances of a baseline IM with a conventional, distributed winding to machines with FSCWs.

Miniature large range multi-axis force-torque sensor for biomechanical applications

A miniature force sensor for the measurement of forces and moments at a human fingertip is designed and realized. Thin silicon pillars inside the sensor provide in-plane guidance for shear force measurement and provide the spring constant in normal direction. A corrugated silicon ring around the force sensitive area provides the spring constant in shear direction and seals the interior of the sensor. To detect all load components, capacitive read-out is used. A novel electrode pattern results in a large shear force sensitivity. The fingertip force sensor has a wide force range of up to 60 N in normal direction, ± 30 N in shear direction and a torque range of ± 25 N mm.

2P1-K09 油圧式4脚ロボットRL-R1の機構設計と脚部の試作

This paper reports on a hydraulic quadruped walking robot, which is designed for the prototype of leg wheel type robot RL-R1. The legs are operated by hydraulic cylinders and rotary actuators. The range of motion and joint torque are set aiming at forest operations or disaster response. We achieved lightweight and high strength leg by using carbon fiber reinforced plastic. This paper shows some preliminary experimental results including squat motion under 165 kg payloads and swing motion at maximum speed. As a result, the developed legs are confirmed to have sufficient torque and strength for our mission.

Effect of high-intensity pulse irradiation with linear polarized near-infrared rays on muscle tone in patients with cerebrovascular disease: a randomized controlled trial.

[Purpose] This study evaluated effects of a high-intensity linear polarized near-infrared ray irradiation for mitigation of muscle hypertonia. [Subjects] The subjects were 20 patients with cerebrovascular disease. [Methods] Subjects were randomly allocated to an intervention or control group. The intervention group received irradiation of the triceps surae. Passive range of motion and passive resistive joint torque of ankle dorsiflexion were measured before and after the intervention in knee extended and flexed positions. [Results] In the knee extended position, the mean changes in passive range of motion were 2.70° and −0.50° in the intervention and control groups, respectively, and the mean changes in passive resistive joint torque were −1.42 and −0.26 N·m in the intervention and control groups, respectively. In the knee flexed position, the mean changes in passive range of motion were 3.70° and 0.70° in the intervention and control groups, respectively, and the mean changes in passive resistive joint torque were −2.38 and −0.31 N·m in the intervention and control groups, respectively. In both knee positions, the mean changes in the two indices were greater in the intervention group than in the control group. [Conclusion] High-intensity linear polarized near-infrared ray irradiation increases passive range of motion and decreases passive resistive joint torque.

출력분기 기반 플러그인 하이브리드 전기자동차의 동력전달 시스템 특성 분석

Abstract : In this paper, powertrain of output split type plug-in hybrid electric vehicle is analyzed for the operation range of speed, torque, and power. First, it is assumed that the efficiency of motor is 100%. And, the speed and torque equations are derived based on the lever analogy. With the above equations, the simulations are performed for the powertrain of output split type plug-in hybrid electric vehicle. From the simulation results, it is found that the output torques of EV1 and series modes are larger than the EV2 and power split modes’ ones. It means the EV1 and series modes can be used for the rapid acceleration. But the EV1 and series modes can be used only the velocity of under the 120 km/h. It is because the motor reaches its maximum speed when the velocity is over the 120 km/h for the EV1 and series modes. When the engine is turned on, the engine power is transmitted through the two motors. But, the power split mode shows the power split of engine at the output shaft, and it has the point of zero motor power. Thus, the transmission efficiency of the power split mode can be higher than the series mode’s one, it the motor efficiency is considered.

Acute effects of static stretching on peak and end-range hamstring-to-quadriceps functional ratios.

To evaluate if static stretching influences peak and end-range functional hamstring-to-quadriceps (H/Q) strength ratios in elite women athletes. Eleven healthy female athletes in an elite competitive level participated to the study. All the participants fulfilled the static stretching or non-stretching (control) intervention protocol in a randomized design on different days. Two static unassisted stretching exercises, one in standing and one in sitting position, were used to stretch both the hamstring and quadriceps muscles during these protocols. The total time for the static stretching was 6 ± 1 min. The isokinetic peak torque measurements for the hamstring and quadriceps muscles in eccentric and concentric modes and the calculations for the functional H/Q strength ratios at angular velocities of 60°/s and 180°/s were made before (pre) and after (post) the control or stretching intervention. The strength measurements and functional strength ratio calculations were based during the entire- and end-range of knee extension. The pre-test scores for quadriceps and hamstring peak torque and end range values were not significantly different between the groups (P > 0.05). Subsequently, although the control group did not exhibit significant changes in quadriceps and hamstring muscle strength (P > 0.05), static stretching decreased eccentric and concentric quadriceps muscle strength at both the 60°/s and 180°/s test speeds (P < 0.01). Similarly, static stretching also decreased eccentric and concentric hamstring muscle strength at both the 60°/s and 180°/s test speeds (P < 0.01). On the other hand, when the functional H/Q strength ratios were taken into consideration, the pre-intervention values were not significant different between the groups both during the entire and end range of knee extension (P > 0.05). Furthermore, the functional H/Q strength ratios exhibited no significant alterations during the entire and end ranges of knee extension both in the static stretching or the control intervention (P > 0.05). According to our results, static stretching routine does not influence functional H/Q ratio. Athletes can confidently perform static stretching during their warm-up routines.

Multiphase starter generator for 48V mini-hybrid powertrain: design and testing

This paper focuses on the design and experimental test results of a belt-driven starter generator for 48-V mini-hybrid powertrains. The functionalities required of the system are engine startup, launch assistant torque, regenerative braking, battery charging, and early fuel cutoff. The cost-effective electrical machine must provide high starting torque and wide constant power speed range, both in motor and generator modes. The authors outline the motivations of the electrical machine topology selection in relation to the specifications and constraints. In particular, a double three-phase induction machine has been selected as a suitable candidate. The aim of this paper is to summarize the design challenges of such kind of electrical machines, mainly subordinated to electromechanical and thermal issues imposed by the considered hybridization solution. Details of the machine design are presented, including a study on multilayer bar stator windings and on rotor slot design. Finally, predicted and measured performances of the prototype are reported and discussed for validation purposes.

SiC-MOSFETスイッチトリラクタンスモータ駆動回路の検討

This paper presents 10 kW SiC-MOSFET converter for driving SRMs. We proposed gate driver which can reduce switching losses and switching delay at the same time. The SRM converter with the proposed gate driver has higher efficient drive capability compared to silicon IGBT. Because of this high efficient drive advantage, we can apply higher switching frequency to reduce current ripple, or add more switching devices to improve converter performances. We improved current control characteristics with 80 kHz switching frequency, and also add some switching devices and boost capacitor to expand output torque range of SRMs.

Efectos a corto plazo del entrenamiento de la marcha en una órtesis robótica (Lokomat®) con retroalimentación auditiva en pacientes con lesión medular incompleta crónica

IntroductionGait training on a robotic orthosis has shown good results in patients with chronic incomplete spinal cord injury (SCI). Auditory feedback in these patients can replace the information normally given by the sensory pathways. ObjectiveTo evaluate the effects of gait training on a robotic orthosis with auditory feedback in patients with chronic SCI. Material and methodsWe studied 31 patients with chronic incomplete SCI, who were randomized to 2 groups. Control group was trained on a robotic orthosis and experimental group received auditory feedback added to robotic orthosis training. Auditory feedback consisted on a metronome whose frequency was equal to gait cadence. The variables measured were spatiotemporal gait (by an instrumented mat), torque, spasticity, and range of motion in the hips and knees (by a robotic orthosis) before and after the assigned treatment. Calculation of variance, covariance and bivariate correlation were conducted for the analysis of results. ResultsWe found a statistically significant improvement in gait speed and cadence, range of motion, torque and spasticity in the experimental group and a positive and significant change in the use of assistive devices for walking. ConclusionsThe proposed program improved gait pattern in patients with chronic SCI. Further studies are needed to assess the persistence of these changes in the long-term, as well as the use of auditory feedback in other disorders.

Deficiencies in Pitching Biomechanics in Baseball Players With a History of Superior Labrum Anterior-Posterior Repair

Background: Baseball pitchers who undergo superior labrum anterior-posterior (SLAP) repair often have trouble returning to their previous level of performance. While the reason is often assumed to be diminished shoulder range of motion or other mechanical changes, differences in pitching biomechanics between baseball pitchers with a history of SLAP repair and pitchers with no injury history have not been studied previously. Hypothesis: The primary hypothesis was that compared with the control group, the SLAP group would exhibit compromised shoulder range of motion (external rotation and horizontal abduction) and internal rotation torque during pitching. Study Design: Controlled laboratory study. Methods: Pitching biomechanics were compared retrospectively between a group of 13 collegiate and professional pitchers with a history of a SLAP tear and a control group of 52 pitchers with no history of surgery; groups were matched by age, height, weight, and pitch velocity. Data were collected with an automated 3-dimensional motion analysis system while participants threw fastballs from the windup. Biomechanics of the shoulder (horizontal abduction and external rotation), elbow (flexion, extension velocity, and flexion torque), and body (stride length, shoulder horizontal adduction, and forward trunk tilt) were compared between the 2 groups. For each variable, a Student t test was used at an α level of .05. Results: Pitchers in the SLAP group exhibited significantly less shoulder horizontal abduction (10.0° ± 13.2° vs 21.0° ± 11.7°, respectively; P = .013) and shoulder external rotation (168.3° ± 12.7° vs 178.3° ± 7.3°, respectively; P = .016) than those in the control group. In addition, players in the SLAP group pitched with a more upright trunk, demonstrated by a less forward trunk tilt at the instant of ball release (30.2° ± 6.3° vs 34.4° ± 6.6°, respectively; P = .048). Conclusion: Pitchers with a history of SLAP repair produce less shoulder horizontal abduction, shoulder external rotation, and forward trunk tilt during pitching than do pitchers with no history of injury. Clinical Relevance: To facilitate normal pitching mechanics, shoulder external rotation and horizontal abduction at 90° should be primary objectives in surgical repair and rehabilitation after SLAP repair. In addition, pitchers should work with their pitching coaches to ensure proper forward trunk tilt.

Wide speed range for traction motor in braking force of electric braking control system

A vehicle stopping method using an electric brake until a traction motor is stopped is studied. At the moment of vehicle stop, electric brake is changed to control mode where torque is reduced at a low speed. Gradient is controlled by estimating the load torque of motor, thereby traction motor is not rotated after stop. In addition, coasting operation and brake test are performed from normal-opposite operation and start using a small-scale model comprising the inertial load equipment and the power converter. Further, traction motor is made to be equipped with a suspension torque. Pure electric braking that makes traction motor stop by an air brake at the time of stop is also implemented. Constant torque range and constant power range are expanded during braking so that braking force is secured with the electric brakes even in high speed region. Therefore, vehicle reduction effect can be expected by reducing parts related with an air brake which is not used frequently by using a pure electric brake in the M car in wide speed region. Further, maintenance of brake system can be reduced. Besides, ride comfort of passenger in the electric rail car, energy efficiency improvement, and noise reduction effect can be additionally expected. Further, an improved brake method that uses only an electric brake till motor stop is proposed by comparing those in the blending brake that uses an air brake while reducing brake torque at vehicle stop.

Isokinetic performance, functionality, and pain level before and after lumbar and pelvic estabilization exercise in individuals with chronic low back pain

Introduction Chronic low back pain with a mechanical and degenerative origin is among the most common symptoms experienced by people all over the world. Objective To analyze the effects of a protocol for lumbar and pelvic segmental stabilization with regard to isokinetic variables, functionality, and pain in patients with low back pain. Materials and methods The sample consisted of 21 subjects, 8 female and 13 male, with a mean age of 42.6 ± 12.5 years. We used tests for mobility (modified Schober index), flexibility (finger-floor distance), functionality (Roland-Morris questionnaire), pain (Visual Analog Scale of Pain), and the isokinetic variables torque peak, work, flexors/extensors ratio before and after application of a protocol for segmental stabilization in subjects with chronic low back pain with a mechanical and degenerative origin. This protocol was used for two months, being applied twice a week. The data were statistically tested by means of the software Statistica, version 8.0. Results There were significant improvements for the variables flexibility (p = 0.014), functionality (p &lt; 0.001), pain level (p &lt; 0.001), torque peak flexion (p = 0.008), torque peak range (p &lt; 0.001), torque flexion (p = 0.001), torque range (p &lt; 0.001), and flexors/extensors ratio (p = 0.001). Conclusion Even with the improved levels of trunk muscles strength, both flexors and extensors, it was not possible to rebalance the segment according to data available in the literature. It is believed that there is a need for a protocol with a longer application period, maintaining the recruitment of extensor muscles. Regarding mobility of the lumbar segment, the protocol showed no significant differences in post-treatment (p = 0.520). This may be attributed to improved muscle control, providing the increased passive stiffness required to promote stability.

Avaliação do torque passivo de flexão plantar e torque ativo de flexão dorsal em ginastas rítmicas e não atletas

O treinamento realizado por atletas de elite acarreta demandas funcionais específicas que produzem mudanças nos tendões e nas propriedades musculares. Nas atletas de ginástica rítmica (GR) há uma exigência maior de controle motor em posições extremas de flexão plantar. Esta demanda pode alterar o torque passivo dos flexores plantares bem como influenciar na amplitude de movimento (ADM) de flexão dorsal e torque dos dorsiflexores. No presente estudo foi comparada a ADM de flexão dorsal de GR e meninas não atletas (MNA), e determinada a correlação entre o torque passivo dos flexores plantares (TPFP) e o torque ativo dos flexores dorsais (TAFD). O estudo incluiu 10 GR e 10 MNA. A ADM de flexão dorsal foi medida com um goniômetro. O TPFP e TAFD foram avaliados por meio de um dinamômetro isocinético em cinco ângulos articulares (20º, 10º, 0º, -10º e -20º). O teste T para amostras independentes foi utilizado para a comparação entre os grupos (α = 0,05). O coeficiente de correlação de Pearson indicou uma correlação negativa alta e moderada entre o TPFP e TAFD para as GR e NA, respectivamente. GR apresentaram menor ADM de flexão dorsal comparadas às MNA. O TPFP foi significativamente maior nas GR comparado as MNA. Por outro lado, o TAFD foi maior nas MNA. A correlação do TPFP com o TAFD foi de r = -0,82; p &lt; 0,01 e r = -0,68; p &lt; 0,01 para GR e MNA, respectivamente. Os resultados sugerem que a alta demanda mecânica nos flexores plantares na GR aumenta o TPFP que pode influenciar negativamente na ADM dos flexores dorsais e no TAFD.

Matching Study of Hydraulic Torque Converter and Engine Based on Genetic Algorithm

According to the multiple matching principles of hydraulic torque converter and engine, a multi-objective optimization mathematical model is established. Genetic Algorithm is used to optimize the matching mathematical model, because the search process is not easy to fall into local optimum. The matching example of YJSW315 type hydraulic torque converter and WD615.67G3-28 type engine is optimized. The design variables’ optimization results are obtained and the figure of optimization results is shown. The matching evaluation indicators of automobile power performance and economy are compared before and after optimization. We can find out that maximum output of hydraulic torque converter torque, highly effective rotational speed range, highly effective torque range, average power output of full working condition range and efficient working condition range are all increased, at the same time, average fuel consumption rate of full working condition range and efficient working condition range are decreased. In accordance with the optimization results, we can see that GA can be used to optimize the matching of engine and hydraulic torque converter.

Design and control of a dual unidirectional brake hybrid actuation system for haptic devices.

Hybrid actuators combining brakes and motors have emerged as an efficient solution to achieve high performance in haptic devices. In this paper, an actuation approach using two unidirectional brakes and a DC motor is proposed. The brakes are coupled to overrunning clutches and can apply a torque in only one rotational direction. The associated control laws, that are independent of the virtual environment model, calculate the control gains in real time in order limit the energy and the stiffness delivered by the motor to ensure stability. The reference torque is respected using the combination of the motor and the brake. Finally, an user experiment has been performed to evaluate the influence of passive and active torque differences in the perception of elasticity. The proposed actuator has a torque range of 0.03 Nm to 5.5 Nm with a 17.75 kNm (-2) torque density.

The relationship between clinically measured hip rotational motion and shoulder biomechanics during the pitching motion.

To examine how clinically measured hip motion is related to shoulder biomechanics during the pitching motion. Cross-sectional. Bilateral hip rotational range of motion was measured clinically among 34 collegiate baseball pitchers. External rotation torque and maximum horizontal adduction range of motion of the throwing shoulder were measured using a three-dimensional, high speed video capture system. Separate standard multiple regression analyses showed that the total hip rotational range of motion of the lead leg had a significant relationship with shoulder external rotation torque during the throwing motion (r=0.56, P=0.003). Both lead leg hip external rotation range of motion (r=-0.39, P=0.02) and internal rotation range of motion (r=0.42, P=0.009) made significant contributions to this dependent variable. Lead leg external rotation range of motion also had a significant negative relationship with shoulder horizontal adduction range of motion (r=-0.36, P=0.04). The total rotational range of motion of the trail leg had a significant relationship with shoulder horizontal adduction range of motion (r=0.43, P=0.04). However, trail leg external rotation range of motion was the only significant contributor to this relationship (r=-0.35, P=0.04). No other significant relationships were noted (r<0.37, P>0.11). Our results demonstrate that altered hip rotational range of motion, measured clinically, has a direct effect on the amount of external rotation torque and horizontal adduction range of motion of the shoulder during the throwing motion.

Monolithic IPMC Fins for Propulsion and Maneuvering in Bioinspired Underwater Robotics

Emerging bioinspired underwater systems, such as autonomous ocean mapping and surveillance vehicles, that maneuver through their environment by mimicking the swimming motion of aquatic animals, can benefit from soft monolithic actuators and control surfaces capable of undergoing complex deformations. Herein, an electrically driven ionic polymer-metal composite (IPMC) artificial muscle with uniquely patterned electrodes for creating complex deformations is presented. The surface electrode pattern on the IPMC is created using a simple surface machining process. By selectively activating specific regions of the IPMC, bending, twisting, flapping, and other bioinspired locomotive behavior can be achieved. For instance, the bending and twisting response of an example 50 mm × 25 mm × 0.5 mm patterned IPMC actuator is characterized to determine its range of motion, output force and torque, as well as its effectiveness as a fish-fin-like propulsor. The experimental results show that the twisting angle exceeds 8 °; the blocking tip force and torque can be as high as 16.5 mN (at 3 V) and 0.83 N·mm (at 4 V), respectively (driven at 0.05 Hz); and an average thrust force of approximately 0.4 mN (driven by 4-V sinusoidal input at 1 Hz) can be generated. These newly developed IPMC fins can be exploited to create novel and efficient propulsors for next-generation underwater robotic vehicles. An example bioinspired robotic fish is presented which exploits the capabilities of the patterned IPMCs for propulsion and maneuvering, where an average maximum swimming speed of approximately 28 mm/s is reported.

Pleated Pneumatic Artificial Muscle-Based Actuator System as a Torque Source for Compliant Lower Limb Exoskeletons

Powered lower limb exoskeletons require high-performance actuator systems, capable of producing zero to high-assistive torque and at the same time yielding to human interaction torques. Such variable impedance can be achieved by the means of compliant actuators. Because of their intrinsic compliance and high force-to-weight ratio pneumatic muscles are a viable option. However, previous pneumatic muscle powered exoskeleton designs either used them as a position source or failed to meet the high-dynamic torque requirements when using them as a torque source. This paper contributes to the improvement of pneumatic muscle-based actuator systems as a torque source for exoskeleton-type robots. The use of pleated pneumatic artificial muscles in a novel actuator system design allows for a higher torque range in a larger range of motion. Performance evaluation results are given for a 1 DOF test setup and a powered knee exoskeleton. The proposed torque controller achieves the dynamic torques required for zero to full assistance at moderate walking speeds.