Planning reaches by evaluating stored postures.

Abstract

This article describes a theory of the computations underlying the selection of coordinated motion patterns, especially in reaching tasks. The central idea is that when a spatial target is selected as an object to be reached, stored postures are evaluated for the contributions they can make to the task. Weights are assigned to the stored postures, and a single target posture is found by taking a weighted sum of the stored postures. Movement is achieved by reducing the distance between the starting angle and target angle of each joint. The model explains compensation for reduced joint mobility, tool use, practice effects, performance errors, and aspects of movement kinematics. Extensions of the model can account for anticipation and coarticulation effects, movement through via points, and hierarchical control of series of movements.

Posture-based or trajectory-based movement planning: a comparison of direct and indirect pointing movements

“…In their study no effect of movement veloc ity on final posture was found, which is consistent with pre dictions by the minimum-work model and by Donders' law. An effect of movement velocity on the final posture would be consistent with predictions by the knowledge model, due to the optimal movement time included in the travel cost crite rion used in the model (Rosenbaum et al, 1995). In addition to variations in the path towards the target position, in start ing position, and in movement velocity, we attached a weight to the forearm of the participant in one of the conditions.…”

“…Moreover, it shows the predictions by various mod els. In the table we included qualitative predictions of Don ders' law (Von Helmholtz, 1867), the equilibrium point hy pothesis (Feldman & Levin, 1995), the minimum angular jerk model (Wada et al, 2001), the minimum torque-change model (Uno et al, 1989), the minimum work model (Soecht ing et al, 1995), the minimum variance model (Harris & Wolpert, 1998), and the knowledge model (Rosenbaum et al, 1995).…”

“…Various models have been proposed to explain the plan ning and execution of arm movements (Feldman & Levin, 1995;Gielen, Vrijenhoek, Flash, & Neggers, 1997;Harris & Wolpert, 1998;Soechting, Buneo, Herrmann, & Flanders, 1995;Rosenbaum, Loukopoulos, Meulenbroek, Vaughan, & Engelbrecht, 1995;Rosenbaum, Meulenbroek, Jansen, & Vaughan, 2001;Uno, Kawato, & Suzuki, 1989). These mod els can be classified into two categories.…”

“…Examples of models within the trajectory-based category are the minimum-work model (Soechting et al, 1995), the minimum torque-change model (Uno et al, 1989), and the minimum-variance model (Harris & Wolpert, 1998). The knowledge model to postu late a new model to account for the cure of Rosenbaum et al, (1995Rosenbaum et al, ( , 2001) is a special case within this classification scheme. In the knowledge model a final posture is selected before movement execution, which would make the model posture-based.…”

Ingredients and a Framework of Dexterous Manipulation Skills for Robots in Human Centered Environment and HRI

“…For performing pick-and-place type manipulation task, we the human, do posture based motion planning [14] [15]. Before planning a path to reach, we first find a single target posture.…”