%0 Journal Article %1 Gribble2000 %A Gribble, Paul L %A Ostry, David J %D 2000 %J Experimental Brain Research %K Arm Equilibrium Human Mathematical Motor learning model movement point · %P 474–482 %R 10.1007/s002210000547 %T Compensation for loads during arm movements using equilibrium-point control %V 135 %X A significant problem in motor control is how information about movement error is used to modify control signals to achieve desired performance. A potential source of movement error and one that is readily controllable experimentally relates to limb dynamics and associated movement-dependent loads. In this paper, we have used a position control model to examine changes to control signals for arm movements in the context of movement- dependent loads. In the model, based on the equilibrium- point hypothesis, equilibrium shifts are adjusted directly in proportion to the positional error between desired and actual movements. The model is used to simulate multi-joint movements in the presence of both “internal” loads due to joint interaction torques, and externally applied loads resulting from velocity-dependent force fields. In both cases it is shown that the model can achieve close correspondence to empirical data using a simple linear adaptation procedure. An important feature of the model is that it achieves compensation for loads during movement without the need for either coordinate transformations between positional error and associated corrective forces, or inverse dynamics calculations.

@article{Gribble2000, abstract = {A significant problem in motor control is how information about movement error is used to modify control signals to achieve desired performance. A potential source of movement error and one that is readily controllable experimentally relates to limb dynamics and associated movement-dependent loads. In this paper, we have used a position control model to examine changes to control signals for arm movements in the context of movement- dependent loads. In the model, based on the equilibrium- point hypothesis, equilibrium shifts are adjusted directly in proportion to the positional error between desired and actual movements. The model is used to simulate multi-joint movements in the presence of both “internal” loads due to joint interaction torques, and externally applied loads resulting from velocity-dependent force fields. In both cases it is shown that the model can achieve close correspondence to empirical data using a simple linear adaptation procedure. An important feature of the model is that it achieves compensation for loads during movement without the need for either coordinate transformations between positional error and associated corrective forces, or inverse dynamics calculations.}, added-at = {2009-06-26T15:25:19.000+0200}, author = {Gribble, Paul L and Ostry, David J}, biburl = {https://www.bibsonomy.org/bibtex/261b0d480d68e9520bfb8fa3d79ed4113/butz}, description = {diverse cognitive systems bib}, doi = {10.1007/s002210000547}, interhash = {b1c687331bceb174f5c1ca4291fac72a}, intrahash = {61b0d480d68e9520bfb8fa3d79ed4113}, journal = {Experimental Brain Research}, keywords = {Arm Equilibrium Human Mathematical Motor learning model movement point ·}, owner = {martin}, pages = {474–482}, review = {A method to adjust EP control signals is proposed. EP is characterised by monothonic shifts between postures in EP state. However, due to internal or external loads, the desired trajectory may deviate from the EP trajectory. In this paper, a learning approach is modeled based on EP control. Thereby, the deviation of desired and actual trajectory is added (after timeshifting) to the EP trajectory. This is possible, because according to the EP theory, the Error Signal and the EP Signal are in the same modality and no conversion between modalities is necessary. This allows the formation of nonmonothonic EP trajectories and fast adjustment of movements due to internal (interaction torques) or external loads. However, as noted in Gribble (1998) or Kalveram (2005), this approach may be insufficient, because EP signal do not necessarily have the same value as the resulting msucle length signals. Additionally, no method of generalization or organization of the changed trajectories is considered.}, timestamp = {2009-06-26T15:25:32.000+0200}, title = {Compensation for loads during arm movements using equilibrium-point control}, volume = 135, year = 2000 }