High-pass filtered positive feedback for decentralized control of cooperation

Cruse, Holk; Bartling, Christian; Kindermann, Thomas A.

doi:10.1007/3-540-59496-5_334

Cited by 16 publications

(5 citation statements)

References 24 publications

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“…To solve the particular problem at hand, WALKNET employs a strategy that is likely to be used by walking animals, in that it uses the distributed control in the form of local positive displacement feedback (Cruse et al 1995c). A related form of positive feedback, but one that monitors force rather than a joint movement, is currently attracting much interest in the study of vertebrate motor control (e.g.…”

Section: Controlling Propulsion: Coordination Of Multiple Legs During Stance (A ) Central Processing Can Hardly Account For Required Adapmentioning

confidence: 99%

Insect walking is based on a decentralized architecture revealing a simple and robust controller

Cruse

Dürr

Schmitz

2006

Phil. Trans. R. Soc. A.

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Control of walking in rugged terrain requires one to incorporate different issues, such as the mechanical properties of legs and muscles, the neuronal control structures for the single leg, the mechanics and neuronal control structures for the coordination between legs, as well as central decisions that are based on external information and on internal states. Walking in predictable environments and fast running, to a large degree, rely on muscle mechanics. Conversely, slow walking in unpredictable terrain, e.g. climbing in rugged structures, has to rely on neuronal systems that monitor and intelligently react to specific properties of the environment. An arthropod model system that shows the latter abilities is the stick insect, based on which this review will be focused. An insect, when moving its six legs, has to control 18 joints, three per leg, and therefore has to control 18 degrees of freedom (d.f.). As the body position in space is determined by 6 d.f. only, there are 12 d.f. open to be selected. Therefore, a fundamental problem is as to how these extra d.f. are controlled. Based mainly on behavioural experiments and simulation studies, but also including neurophysiological results, the following control structures have been revealed. Legs act as basically independent systems. The quasi-rhythmic movement of the individual leg can be described to result from a structure that exploits mechanical coupling of the legs via the ground and the body. Furthermore, neuronally mediated influences act locally between neighbouring legs, leading to the emergence of insect-type gaits. The underlying controller can be described as a free gait controller. Cooperation of the legs being in stance mode is assumed to be based on mechanical coupling plus local positive feedback controllers. These controllers, acting on individual leg joints, transform a passive displacement of a joint into an active movement, generating synergistic assistance reflexes in all mechanically coupled joints. This architecture is summarized in the form of the artificial neural network, Walknet, that is heavily dependent on sensory feedback at the proprioceptive level. Exteroceptive feedback is exploited for global decisions, such as the walking direction and velocity.

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Section: Controlling Propulsion: Coordination Of Multiple Legs During Stance (A ) Central Processing Can Hardly Account For Required Adapmentioning

confidence: 99%

Insect walking is based on a decentralized architecture revealing a simple and robust controller

Cruse

Dürr

Schmitz

2006

Phil. Trans. R. Soc. A.

Self Cite

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“…To solve this problem in a distributed way, we propose to replace a central controller with distributed control in the form of local "high-pass filtered positive feedback" at the joint level (Cruse, Bartling, & Kindermann, 1995). According to this principle the desired angular position of a single joint (i.e., the reference value of a subsequent negative feedback loop on position) is calculated in each time step by feeding back the actual angular velocity of that single joint (Figure 3).…”

Section: High-pass Filtered Positive Feedbackmentioning

confidence: 99%

Behavior and Adaptability of a Six-Legged Walking System with Highly Distributed Control

Kindermann

2001

Adaptive Behavior

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A situated, moderately complex kinematic system-here an 18-degree-of-freedom six-legged walking system-can show a variety of behaviors, even when controlled by a relatively simple controller. Therefore, a detailed quantitative study of the behavior of such a system is necessary to achieve an understanding of its properties. This "artificial ethology" is applied to a controller with a decentralized structure that uses essential design characteristics of its biological model, the stick insect. The system takes advantage of recurrent connections that establish a loop through the environment. Despite its completely reactive nature, the system can adapt to unpredictable external conditions with no need for specific reprogramming. Leg trajectories are always adapted such that mechanical stress is reduced. This even holds true for special situations like, for example, walking over obstacles, stumbling, or walking with partially or totally amputated legs. Similarities and important discrepancies between the model's behavior and the walking behavior of stick insects are discussed.

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“…In contrast, nature has invented local control strategies based on positive feedback (also called reflex reversal) that could be used for the generation of compliant motions for example in legs during the stance phase of walking (Bässler 1976;Schmitz et al 1995;Cruse et al 1995;Kindermann 2002). Based on this biological paragon, local positive velocity feedback (LPVF) controllers have been developed (Schneider et al 2005a,b).…”

Section: Discussionmentioning

confidence: 96%

Winching up heavy loads with a compliant arm: a new local joint controller

2008

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A closed kinematic chain, like an arm that operates a crank, has a constrained movement space. A meaningful movement of the chain's endpoint is only possible along the free movement directions which are given implicitly by the contour of the object that confines the movement of the chain. Many technical solutions for such a movement task, in particular those used in robotics, use central controllers and force-torque sensors in the arm's wrist or a leg's ankle to construct a coordinate system (task frame formalism) at the local point of contact the axes of which coincide with the free and constrained movement directions. Motivated by examples from biology, we introduce a new control system that solves a constrained movement task. The control system is inspired by the control architecture that is found in stick insects like Carausius morosus. It consists of decentral joint controllers that work on elastic joints (compliant manipulator). The decentral controllers are based on local positive velocity feedback (LPVF). It has been shown earlier that LPVF enables contour following of a limb in a compliant motion task without a central controller. In this paper we extend LPVF in such a way that it is even able to follow a contour if a considerable counter force drags the limb away along the contour in a direction opposite to the desired. The controller extension is based on the measurement of the local mechanical power generated in the elastic joint and is called power-controlled relaxation LPVF. The new control approach has the following advantages. First, it still uses local joint controllers without knowledge of the kinematics. Second, it does not need a force or torque measurement at the end of the limb. In this paper we test power-controlled relaxation LPVF on a crank turning task in which a weight has to be winched up by a two-joint compliant manipulator.

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High-pass filtered positive feedback for decentralized control of cooperation

Cited by 16 publications

References 24 publications

Insect walking is based on a decentralized architecture revealing a simple and robust controller

Insect walking is based on a decentralized architecture revealing a simple and robust controller

Behavior and Adaptability of a Six-Legged Walking System with Highly Distributed Control

Winching up heavy loads with a compliant arm: a new local joint controller

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