Adaptive load feedback robustly signals force dynamics in robotic model of Carausius morosus stepping

Animals utilize a number of neuronal systems to produce locomotion. One type of sensory organ that contributes in insects is the campaniform sensillum (CS) that measures the load on their legs. Groups of the receptors are found on high stress regions of the leg exoskeleton and they have significant effects in adapting walking behavior. Recording from these sensors in freely moving animals is limited by technical constraints. To better understand the load feedback signaled by CS to the nervous system, we have constructed a dynamically scaled robotic model of the Carausius morosus stick insect middle leg. The leg steps on a treadmill and supports weight during stance to simulate body weight. Strain gauges were mounted in the same positions and orientations as four key CS groups (Groups 3, 4, 6B, and 6A). Continuous data from the strain gauges were processed through a previously published dynamic computational model of CS discharge. Our experiments suggest that under different stepping conditions (e.g., changing “body” weight, phasic load stimuli, slipping foot), the CS sensory discharge robustly signals increases in force, such as at the beginning of stance, and decreases in force, such as at the end of stance or when the foot slips. Such signals would be crucial for an insect or robot to maintain intra- and inter-leg coordination while walking over extreme terrain

Neurobiology: Reconstructing the Neural Control of Leg Coordination

SummaryWalking is adaptable because the timing of movements of individual legs can be varied while maintaining leg coordination. Recent work in stick insects shows that leg coordination set by interactions of pattern generating circuits can be overridden by sensory feedback

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Biological systems can provide useful insights into principles of design and control of locomotion that can be applied to legged robots. In this paper we review our work on cockroaches using finite element analysis to model how loads are sensed and regulated in walking and climbing. A number of biological studies have shown that sensors that detect forces in the legs of insects are of particular importance in controlling walking and adapting locomotion to non-horizontal terrains. Our analysis strongly suggests that (i) the system can detect specific force vectors (body load versus propulsion) via sensors located in the leg in positions close to the body and (ii) the system uses this information in positive load feedback to regulate walking movements. These principles and design elements provide examples that can be applied in legged locomotion in walking machines. KEY WORDS—strain sensors, control, cockroaches, campaniform sensilla, finite element analysi

Encoding of force increases and decreases by tibial campaniform sensilla in the stick insect, Carausius morosus

Zill SN, Büschges A, Schmitz J. Encoding of force increases and decreases by tibial campaniform sensilla in the stick insect, Carausius morosus. Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology. 2011;197(8):851-867

Incorporating sensory signals of substrate grip/adherence in force control

Zill S, Chaudry S, Büschges A, Schmitz J. Incorporating sensory signals of substrate grip/adherence in force control. In: Proceedings of the 43th annual meeting Society for Neuroscience. 2013

Detecting forces in a reference frame: responses of stick insect campaniform sensilla to muscle forces and loads

Zill S, Büschges A, Chaudhry S, Schmitz J. Detecting forces in a reference frame: responses of stick insect campaniform sensilla to muscle forces and loads. In: Proceedings of the 42nd annual meeting of the Society for Neuroscience. Society for Neuroscience; 2012

Responses of stick insect tibial campaniform sensilla to muscle forces and loads and their relation to the plane of leg movement

Schmitz J, Büschges A, Chaudhry S, Zill S. Responses of stick insect tibial campaniform sensilla to muscle forces and loads and their relation to the plane of leg movement. In: Proceedings of the 42nd annual meeting of the Society for Neuroscience. Society for Neuroscience; 2012

Discrete sensory encoding of force increases or decreases in the stick insect leg

Zill S, Chaudhry S, Büschges A, Schmitz J. Discrete sensory encoding of force increases or decreases in the stick insect leg. Presented at the Society for Neuroscience, Washington