Multi-finger prehension: control of a redundant mechanical system.

The human hand has been a fascinating object of study for researchers in both biomechanics and motor control. Studies of human prehension have contributed significantly to the progress in addressing the famous problem of motor redundancy. After a brief review of the hand mechanics, we present results of recent studies that support a general view that the apparently redundant design of the hand is not a source of computational problems but a rich apparatus that allows performing a variety of tasks in a reliable and flexible way (the principle of abundance). Multi-digit synergies have been analyzed at two levels of a hypothetical hierarchy involved in the control of prehensile actions. At the upper level, forces and moments produced by the thumb and virtual finger (an imagined finger with a mechanical action equal to the combined mechanical action of all four fingers of the hand) co-vary to stabilize the gripping action and the orientation of the hand-held object. These results support the principle of superposition suggested earlier in robotics with respect to the control of artificial grippers. At the lower level of the hierarchy, forces and moments produced by individual fingers co-vary to stabilize the magnitude and direction of the force vector and the moment of force produced by the virtual finger. Adjustments to changes in task constraints (such as, for example, friction under individual digits) may be local and synergic. The latter reflect multi-digit prehension synergies and may be analyzed with the so-called chain effects: Sequences of relatively straightforward cause-effect links directly related to mechanical constraints leading to non-trivial strong co-variation between pairs of elemental variables. Analysis of grip force adjustments during motion of hand-held objects suggests that the central nervous system adjusts to gravitational and inertial loads differently. The human hand is a gold mine for researchers interested in the control of natural human movements.

[1]  Todd C. Pataky,et al.  Finger interaction during maximal radial and ulnar deviation efforts: experimental data and linear neural network modeling , 2007, Experimental Brain Research.

[2]  K. Newell,et al.  The scaling of human grip configurations. , 1999, Journal of experimental psychology. Human perception and performance.

[3]  Jae Kun Shim,et al.  Rotational equilibrium during multi-digit pressing and prehension. , 2004, Motor control.

[4]  W. Rymer,et al.  Strategies for muscle activation during isometric torque generation at the human elbow. , 1989, Journal of neurophysiology.

[5]  M. Latash,et al.  Finger synergies during multi-finger cyclic production of moment of force , 2007, Experimental Brain Research.

[6]  M. Latash,et al.  Effects of friction at the digit-object interface on the digit forces in multi-finger prehension , 2006, Experimental Brain Research.

[7]  M. Arbib.  Coordinated control programs for movements of the hand , 1985 .

[8]  K. J. Cole,et al.  Kinematic and electromyographic responses to perturbation of a rapid grasp. , 1987, Journal of neurophysiology.

[9]  Moshe Hershkovitz,et al.  Toeard a formulation of the human grasping quality sense , 1995, J. Field Robotics.

[10]  Todd C. Pataky,et al.  Prehension synergies during nonvertical grasping, I: experimental observations , 2004, Biological Cybernetics.

[11]  S. Gandevia,et al.  Limited independent flexion of the thumb and fingers in human subjects. , 1994, The Journal of physiology.

[12]  Vladimir M. Zatsiorsky,et al.  Force and torque production in static multifinger prehension: biomechanics and control. I. Biomechanics , 2002, Biological Cybernetics.

[13]  Vladimir M. Zatsiorsky,et al.  A central back-coupling hypothesis on the organization of motor synergies: a physical metaphor and a neural model , 2005, Biological Cybernetics.

[14]  F. Zajac,et al.  Large index-fingertip forces are produced by subject-independent patterns of muscle excitation. , 1998, Journal of biomechanics.

[15]  W. Rymer,et al.  Characteristics of synergic relations during isometric contractions of human elbow muscles. , 1986, Journal of neurophysiology.

[16]  Mark L Latash,et al.  Viscoelastic response of the finger pad to incremental tangential displacements. , 2005, Journal of biomechanics.

[17]  R. Johansson,et al.  Factors influencing the force control during precision grip , 2004, Experimental Brain Research.

[18]  Wen-Han Qian,et al.  A general dynamic force distribution algorithm for multifingered grasping , 2000, IEEE Trans. Syst. Man Cybern. Part B.

[19]  Bernard Roth,et al.  Analysis of Multifingered Hands , 1986 .

[20]  F. Lacquaniti,et al.  Coordination of Locomotion with Voluntary Movements in Humans , 2005, The Journal of Neuroscience.

[21]  Karl M Newell,et al.  Inter-digit individuation and force variability in the precision grip of young, elderly, and Parkinson's disease participants. , 2002, Motor control.

[22]  T D Sanger,et al.  Human Arm Movements Described by a Low-Dimensional Superposition of Principal Components , 2000, The Journal of Neuroscience.

[23]  M. Latash,et al.  Prehension synergies: trial-to-trial variability and principle of superposition during static prehension in three dimensions. , 2005, Journal of neurophysiology.

[24]  Joseph D. Towles,et al.  Quantification of fingertip force reduction in the forefinger following simulated paralysis of extensor and intrinsic muscles. , 2000, Journal of biomechanics.

[25]  Sensitivity analysis for a class of robotic grasping quality functionals , 1998, Robotica.

[26]  Umberto Castiello,et al.  Insights into the reach to grasp movement , 1994 .

[27]  J. F. Soechting,et al.  Force synergies for multifingered grasping , 2000, Experimental Brain Research.

[28]  K. J. Cole,et al.  Grip force adjustments evoked by load force perturbations of a grasped object. , 1988, Journal of neurophysiology.

[29]  Michael I. Jordan,et al.  Optimal feedback control as a theory of motor coordination , 2002, Nature Neuroscience.

[30]  U. Castiello.  The neuroscience of grasping , 2005, Nature Reviews Neuroscience.

[31]  Tomoko Aoki,et al.  Adjustments to Local Friction in Multifinger Prehension , 2007, Journal of motor behavior.

[32]  T. Nichols.  A biomechanical perspective on spinal mechanisms of coordinated muscular action: an architecture principle. , 1994, Acta anatomica.

[33]  J. Kenneth Salisbury,et al.  Articulated Hands , 1982 .

[34]  R. Johansson,et al.  Independent control of human finger‐tip forces at individual digits during precision lifting. , 1992, The Journal of physiology.

[35]  Kelly J. Cole,et al.  Distributing vertical forces between the digits during gripping and lifting: the effects of rotating the hand versus rotating the object , 2004, Experimental Brain Research.

[36]  Thea Iberall,et al.  Dextrous robot hands , 1990 .

[37]  R. S. Johansson,et al.  Roles of glabrous skin receptors and sensorimotor memory in automatic control of precision grip when lifting rougher or more slippery objects , 2004, Experimental Brain Research.

[38]  M. Latash,et al.  Enslaving effects in multi-finger force production , 2000, Experimental Brain Research.

[39]  Gregor Schöner,et al.  Understanding finger coordination through analysis of the structure of force variability , 2002, Biological Cybernetics.

[40]  M. Schieber,et al.  Differential impairment of individuated finger movements in humans after damage to the motor cortex or the corticospinal tract. , 2003, Journal of neurophysiology.

[41]  A. Goodwin,et al.  Hand function and the neocortex , 1985 .

[42]  Gregor Schöner,et al.  A mode hypothesis for finger interaction during multi-finger force-production tasks , 2003, Biological Cybernetics.

[43]  M. Latash,et al.  Muscle synergies during shifts of the center of pressure by standing persons , 2003, Experimental Brain Research.

[44]  G. E. Loeb,et al.  A hierarchical foundation for models of sensorimotor control , 1999, Experimental Brain Research.

[45]  Marc H Schieber,et al.  Hand function: peripheral and central constraints on performance. , 2004, Journal of applied physiology.

[46]  M. Latash,et al.  Finger coordination during discrete and oscillatory force production tasks , 2002, Experimental Brain Research.

[47]  Todd C. Pataky,et al.  Prehension synergies during nonvertical grasping, II: Modeling and optimization , 2004, Biological Cybernetics.

[48]  Suguru Arimoto,et al.  Principles of superposition for controlling pinch motions by means of robot fingers with soft tips , 2001, Robotica.

[49]  Vladimir M. Zatsiorsky,et al.  Multi-digit maximum voluntary torque production on a circular object , 2007, Ergonomics.

[50]  N. A. Bernshteĭn.  The co-ordination and regulation of movements , 1967 .

[51]  Fan Gao,et al.  The principle of superposition in human prehension , 2004, Robotica.

[52]  Fan Gao,et al.  Internal forces during object manipulation , 2005, Experimental Brain Research.

[53]  Hikaru Inooka,et al.  Characteristics of human fingertips in the shearing direction , 2000, Biological Cybernetics.

[54]  Jae Kun Shim,et al.  Prehension synergies in three dimensions. , 2005, Journal of neurophysiology.

[55]  E. Robertson,et al.  Neural features of the reach and grasp. , 2000, Motor control.

[56]  E. Bizzi,et al.  Muscle synergies encoded within the spinal cord: evidence from focal intraspinal NMDA iontophoresis in the frog. , 2001, Journal of neurophysiology.

[57]  Lena H Ting,et al.  A limited set of muscle synergies for force control during a postural task. , 2005, Journal of neurophysiology.

[58]  Albert Einstein,et al.  The evolution of physics : from the early concepts to relativity and quanta , 1967 .

[59]  Andrea d'Avella,et al.  Matrix factorization algorithms for the identification of muscle synergies: evaluation on simulated and experimental data sets. , 2006, Journal of neurophysiology.

[60]  B I Prilutsky,et al.  Coordination of two- and one-joint muscles: functional consequences and implications for motor control. , 2000, Motor control.

[61]  C. D. Mote,et al.  Force response of the fingertip pulp to repeated compression--effects of loading rate, loading angle and anthropometry. , 1997, Journal of biomechanics.

[62]  Fan Gao,et al.  Prehension stability: experiments with expanding and contracting handle. , 2006, Journal of neurophysiology.

[63]  Vladimir M. Zatsiorsky,et al.  Motor control goes beyond physics: differential effects of gravity and inertia on finger forces during manipulation of hand-held objects , 2005, Experimental Brain Research.

[64]  R. Johansson,et al.  Control of grasp stability in humans under different frictional conditions during multidigit manipulation. , 1999, Journal of neurophysiology.

[65]  M. Latash,et al.  Motor Control Strategies Revealed in the Structure of Motor Variability , 2002, Exercise and sport sciences reviews.

[66]  M. Latash,et al.  Control of finger force direction in the flexion-extension plane , 2005, Experimental Brain Research.

[67]  Vladimir M. Zatsiorsky,et al.  Finger coordination during moment production on a mechanically fixed object , 2004, Experimental Brain Research.

[68]  Arthur D. Kuo,et al.  A mechanical analysis of force distribution between redundant, multiple degree-of-freedom actuators in the human: Implications for the central nervous system , 1994 .

[69]  M. Latash,et al.  Age-related changes in finger coordination in static prehension tasks. , 2004, Journal of applied physiology.

[70]  H. Kinoshita,et al.  Individual finger forces acting on a grasped object during shaking actions. , 1996, Ergonomics.

[71]  Christine L. MacKenzie,et al.  The Grasping Hand , 2011, The Grasping Hand.

[72]  M. Latash,et al.  Structure of motor variability in marginally redundant multifinger force production tasks , 2001, Experimental Brain Research.

[73]  Fan Gao,et al.  Neural network modeling supports a theory on the hierarchical control of prehension , 2004, Neural Computing & Applications.

[74]  Mark Latash,et al.  Tangential load sharing among fingers during prehension , 2004, Ergonomics.

[75]  T. Ohtsuki.  Inhibition of individual fingers during grip strength exertion. , 1981, Ergonomics.

[76]  M. Flanders,et al.  Arm muscle activation for static forces in three-dimensional space. , 1990, Journal of neurophysiology.

[77]  J. Flanagan,et al.  The stability of precision grip forces during cyclic arm movements with a hand-held load , 1990, Experimental Brain Research.

[78]  J. Massion,et al.  Axial synergies during human upper trunk bending , 1998, Experimental Brain Research.

[79]  F. Lacquaniti,et al.  Five basic muscle activation patterns account for muscle activity during human locomotion , 2004, The Journal of physiology.

[80]  M. L. Tsetlin,et al.  Models of the Structural-Functional Organization of Certain Biological Systems , 1971 .

[81]  J. F. Soechting,et al.  Modulation of grasping forces during object transport. , 2005, Journal of neurophysiology.

[82]  M. Latash,et al.  Prehension synergies: trial-to-trial variability and hierarchical organization of stable performance , 2003, Experimental Brain Research.

[83]  Gregor Schöner,et al.  The uncontrolled manifold concept: identifying control variables for a functional task , 1999, Experimental Brain Research.

[84]  B. Vereijken,et al.  Free(z)ing Degrees of Freedom in Skill Acquisition , 1992 .

[85]  Mark L. Latash,et al.  Feed-forward control of a redundant motor system , 2006, Biological Cybernetics.

[86]  J. Flanagan,et al.  Modulation of grip force with load force during point-to-point arm movements , 2004, Experimental Brain Research.

[87]  Richard M. Murray,et al.  A Mathematical Introduction to Robotic Manipulation , 1994 .

[88]  R. Howe,et al.  Human grasp choice and robotic grasp analysis , 1990 .

[89]  Sun Wook Kim,et al.  Anticipatory adjustments of multi-finger synergies in preparation for self-triggered perturbations , 2006, Experimental Brain Research.

[90]  C J Snijders,et al.  The hand of the musician: the kinematics of the bidigital finger system with anatomical restrictions. , 1993, Journal of biomechanics.

[91]  Tsuneo Yoshikawa,et al.  Manipulating and grasping forces in manipulation by multifingered robot hands , 1987, IEEE Trans. Robotics Autom..

[92]  C. D. Mote,et al.  A structural model of the forced compression of the fingertip pulp. , 1998, Journal of biomechanics.

[93]  M. Latash,et al.  Force sharing among fingers as a model of the redundancy problem , 1998, Experimental Brain Research.

[94]  M. Latash,et al.  Accurate production of time-varying patterns of the moment of force in multi-finger tasks , 2006, Experimental Brain Research.

[95]  M. Latash,et al.  Prehension synergies: Effects of object geometry and prescribed torques , 2002, Experimental Brain Research.

[96]  Karl M Newell,et al.  Task goals and change in dynamical degrees of freedom with motor learning. , 2003, Journal of experimental psychology. Human perception and performance.