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Exploration of Hardware/Softw are Design Space through a Codesign of Robot Arm Controller: (1996)This paper deals with exploration of hardware/softw are design space. The analysis is illustrated using a design of robot arm controller. The controller makes use of an adaptive speed control in real-time. Several architectural solutions will be discussed with regard to their performance and cost. The goal is to select the best solution that satisfies the real-time constraints and minimizes the cost.M Abid, A Changuel, A Jerraya

Source: (1996)
Parallel computations for controlling an arm.: J Mot Behav, Vol. 16, No. 2. (June 1984), pp. 171-194.In order to control a reaching movement of the arm and body, several different computational problems must be solved. Some parallel methods that could be implemented in networks of neuron-like processors are described. Each method solves a different part of the overall task. First, a method is described for finding the torques necessary to follow a desired trajectory. The methods is more economical and more versatile than table look-up and requires very few sequential steps. Then a way of generating an internal representation of a desired trajectory is described. This method shows the trajectory one piece at a time by applying a large set of heuristic rules to a "motion blackboard" that represents the static and dynamic parameters of the state of the body at the current point in the trajectory. The computations are simplified by expressing the positions, orientations, and motions of parts of the body in terms of a single, non-accelerati ng, world-based frame of reference, rather than in terms of the joint-angles or an egocentric frame based on the body itself.G Hinton

Source: J Mot Behav, Vol. 16, No. 2. (June 1984), pp. 171-194.
Profile guided selection of ARM and thumb instructions: (2002), pp. 56-64.Arvind Krishnaswamy, Rajiv Gupta

Source: (2002), pp. 56-64.
Robots can teach people how to move their arm: Robotics and Automation, 2000. Proceedings. ICRA '00. IEEE International Conference on, Vol. 1 (2000), pp. 300-305 vol.1.Describe s a new theoretical framework for robot-aided training of arm movements. This framework is based on recent studies of motor adaptation in human subjects and on general considerations about adaptive control of artificial and biological systems. The authors propose to take advantage of the adaptive processes through which subjects, when exposed to a perturbing field, develop an internal model of the field as a relation between experienced limb states and forces. The problem of teaching new movements is then reduced to the problem of designing force fields capable of inducing the desired movements as after-effects of the adaptation triggered by prolonged exposure to the fields. This approach is an alternative to more standard training methods based on the explicit specification of the desired movement to the learner. Unlike these methods, the adaptive process does not require explicit awareness of the desired movement as adaptation is uniquely concerned with restoring a preexisting kinematic pattern after a change in dynamical environmentFA Mussa-Ivaldi, JL Patton

Source: Robotics and Automation, 2000. Proceedings. ICRA '00. IEEE International Conference on, Vol. 1 (2000), pp. 300-305 vol.1.
Jerk-cost modulations during the practice of rapid arm movements: Biological Cybernetics, Vol. 60, No. 3. (1 January 1989), pp. 221-230.We examined how hand-trajector y smoothness changed during the practice of a motor task where smoothness was quantified by jerk-cost. Four human subjects each moved his nondominant arm between an upper target and a lower target, while circumnavigati ng a barrier that extended outward from the vertical plane of the targets. The two targets and the barrier placed boundary constraints on hand trajectories, but the motion was not restrained in any other way. Arm movements were recorded on high-speed ciné film, and linear and angular kinematical data were obtained for all arm segments. In each of 100 practice trials, subjects attempted to minimize movement time. After the practice trials, subjects repeated the same motor task but at movement times corresponding to the slowest, mid-range and fastest motion that had occurred during practice. Thus, jerk-cost could be compared for movements of different speeds during practice and after practice. Because the movement task contained several changes in hand-path direction, the changes in the vector characteristic s of the hand accelerations were expected to be important for explaining the modulations in jerk-cost with practice. Total jerk-cost, therefore, was calculated as well as the separate magnitudinal and directional jerk-cost components. During practice, total movement time decreased, hand paths became more parabolic in shape, and significant changes occurred in hand acceleration magnitude, direction, and timing. Total jerk-cost and the magnitudinal and directional jerk-cost components were significantly less when slowest hand movements were compared after practice versus during practice. The decrease in jerk-cost indicated an increased smoothness of the practiced movements.K Schneider, RF Zernicke

Source: Biological Cybernetics, Vol. 60, No. 3. (1 January 1989), pp. 221-230.
The coordination of arm movements: an experimentally confirmed mathematical model.: J Neurosci, Vol. 5, No. 7. (July 1985), pp. 1688-1703.This paper presents studies of the coordination of voluntary human arm movements. A mathematical model is formulated which is shown to predict both the qualitative features and the quantitative details observed experimentally in planar, multijoint arm movements. Coordination is modeled mathematically by defining an objective function, a measure of performance for any possible movement. The unique trajectory which yields the best performance is determined using dynamic optimization theory. In the work presented here, the objective function is the square of the magnitude of jerk (rate of change of acceleration) of the hand integrated over the entire movement. This is equivalent to assuming that a major goal of motor coordination is the production of the smoothest possible movement of the hand. Experimental observations of human subjects performing voluntary unconstrained movements in a horizontal plane are presented. They confirm the following predictions of the mathematical model: unconstrained point-to-point motions are approximately straight with bell-shaped tangential velocity profiles; curved motions (through an intermediate point or around an obstacle) have portions of low curvature joined by portions of high curvature; at points of high curvature, the tangential velocity is reduced; the durations of the low-curvature portions are approximately equal. The theoretical analysis is based solely on the kinematics of movement independent of the dynamics of the musculoskeleta l system and is successful only when formulated in terms of the motion of the hand in extracorporal space. The implications with respect to movement organization are discussed.T Flash, N Hogan

Source: J Neurosci, Vol. 5, No. 7. (July 1985), pp. 1688-1703.
Harvest Scheduling Subject to Maximum Area Restrictions: Exploring Exact Approaches: Oper. Res., Vol. 53, No. 3. (May 2005), pp. 490-500.Marcos Goycoolea, Alan Murray, Francisco Barahona, Rafael Epstein, Andrés Weintraub

Source: Oper. Res., Vol. 53, No. 3. (May 2005), pp. 490-500.
A statistical investigation of the in vivo biomechanical properties of the human shoulder complex: Mathematical and Computer Modelling, Vol. 12, No. 12. (1989), pp. 1569-1582.Util ization of the multi-segmente d total-human-bo dy models in the simulation of human response to external forces provides an essential input for the injury prediction criteria as well as subsequent design and development of crash protection systems. The effectiveness of these models to accurately predict live-human response depends heavily on the proper biomechanical description of the major articulating joints. In a research effort to obtain in vivo joint property data, the senior author and his associates have developed a data collection methodology by means of sonic emitters. This paper presents a statistical investigation on the kinematics of and passive resistive properties beyond the maximal voluntary sinus of the human shoulder complex for the male population of ages 18-32. Ten subjects were randomly chosen to form the sample. Furthermore, to the knowledge of the authors this paper, for the first time, deals with the subtle arguments related to the choice of a subject-based local joint axis system or a statistically determined sample mean joint axis system to present the data in the most appropriate fashion. The statistical results are obtained in a compact manner so that the results can be easily incorporated into existing mathematical multi-segmente d models of the total human body. Finally, the ultimate overall performance of the data acquisition system and efficacy of the associated data analysis technique are manifested by the good repeatability of the sample means and sample standard deviations from three kinematic test runs made on the same sample.AE Engin, SM Chen

Source: Mathematical and Computer Modelling, Vol. 12, No. 12. (1989), pp. 1569-1582.
Biomechanical characterizati on of the stretch reflex activity as an approach to spasticity measurement and modeling-a pilot study: Engineering in Medicine and Biology Society, 2003. Proceedings of the 25th Annual International Conference of the IEEE, Vol. 2 (2003), pp. 1491-1494 Vol.2.Spastici ty is a clinical condition that may develop in people with central nervous system injuries. It is believed that spasticity results from changes in the excitability of the stretch reflex pathways manifesting clinically as a velocity dependent increase in resistance to passive movement (RTPM) and exaggerated tendon jerks. A biomechanical device was designed to provide a 90 ms torque controlled stretch to the biceps brachii. The stretch reflex response was recorded using surface electromyograp hy and angular displacement with a potentiometer. A pilot study was carried out in four stroke and one non-impaired volunteers. Four different magnitudes of torque were applied to the elbow. Stretch reflex characterisati on was done on EMG data collected 150 ms before and to complete 450 ms after the perturbation. The outcome measures were the range of movement, the amplitude of the rectified reflex response and, the latency, rise time and duration of the smoothed reflex response. The reflex in the stroke patients was not significantly different from normals (p>0.10). The mechanical model developed suggest that changes in reflex excitability may not necessarily contribute to joint stiffness (r/sup 2/>0.9).J Salazar-Torres , AD Pandyan, CIM Price, RI Davidson, MP Barnes, GR Johnson

Source: Engineering in Medicine and Biology Society, 2003. Proceedings of the 25th Annual International Conference of the IEEE, Vol. 2 (2003), pp. 1491-1494 Vol.2.
Viscoelastic properties of human skin and processed dermis: Skin Research and Technology, No. 7. (February 2001), pp. 18-23.Backgrou nd/aims: The purpose of this work is to attempt to determine the elastic spring constant for collagen and elastic fibers (elastin) in skin and to detemine if the values of these elastic constants are similar to those reported for other tissues.Method s: We studied the viscoelastic mechanical properties of human skin and dermis by measuring the incremental stress-strain behavior. Elastic stress-strain curves were used to obtain the elastic spring constant of elastin and collagen while the collagen fibril length was obtained from the slope of viscous stress-strain curves.Results : Our results suggest that the elastic spring constant for elastin is about 4.0 MPa while that for collagen is about 4.4 GPa. The former value is similar to that calculated for ligamentum nuchae while the latter value is about 70% of the value found for tendon and self-assembled type I collagen fibers. The differences between the elastic constants for collagen molecules in tendon and skin is hypothesized to reflect the higher molecular tilt angle and lower D period found in skin compared to tendon as well as a shorter fibril length.Conclus ion: The differences in the collagen types present in skin and tendon may influence collagen self-assembly and the resulting viscoelastic properties.FH Silver, JW Freeman, D Devore

Source: Skin Research and Technology, No. 7. (February 2001), pp. 18-23.

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