ISSN:
1432-0770
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
,
Informatik
,
Physik
Notizen:
Abstract - The main purpose of this paper is to demonstrate that the walking cycle with all of its complexity as the major coordinating cues can be modelled by a purely kinematic approach. - The behavioural results and locomotor rules described in the previous paper (I) form a basis for constructing a computer model able to simulate walking sequences. - The spatial and temporal parameters of an isolated stepping leg are computed (Fig. 1) by using simple recursive methods adapted from first order auto-regressive algorithms. This single leg model attempts to simulate the control of leg position during walking, as it appears to be carried out when a real appendage operates its return stroke (Fig. 2). - A more complete model is then designed to establish a valid coordinated state within an arbitrary pair of legs, either ipsi- or contralateral (Fig. 3). The interactions are reproduced by three adjustable coefficients simulating the concepts of coupling, hierarchy and strategy defined in the first paper. - The precise functioning of the model is described by analyzing some theoretical simulated sequences where extreme and non-physiological values were assigned to the stepping parameters (Figs. 4, 5, and 6). - The model reliability is then examined by comparing its performances in the simulation of real and rather complex walking sequences (Figs. 7 and 8). The results obtained are discussed in order to justify our hypothesis, and to confirm the validity of the coordinating mechanisms proposed. lobster treadmill walking) could be summarized in a set of a few parameters, despite its apparent complexity. Our purpose is now to integrate these results in a “simple” computer model which can be easily simulated. The desired model attempts to fit any leg pair and must satisfy two goals: (i) It must generate simulated walking sequences by creating successive step cycles analogous to the ones really performed by the rock lobster's legs. (ii) It must also produce different coordinated states depending upon boththe characteristics of the particular leg pair, and the experimental conditions. If these conditions are fulfilled, such a model would be very useful to test the validity of our hypothesis, and also to predict some of the behavioural reactions expected under unusual constraints. The model was designed in two successive stages: 1- Single leg stepping; 2- Relationships between two legs. The calculation program, written in BASIC, is run on a minicomputer (MINC 11/23, Digital Equipments) and the graphic representation of stepping sequences is performed using a numeric plotter (Tekronix 4662).
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00341932
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