scholarly journals CONTROL OF BODY HEIGHT IN A STICK INSECT WALKING ON A TREADWHEEL

1993 ◽  
Vol 181 (1) ◽  
pp. 141-155 ◽  
Author(s):  
H. Cruse ◽  
J. Schmitz ◽  
U. Braun ◽  
A. Schweins
Keyword(s):  
Control System ◽  
Linear Relationship ◽  
Closed Loop ◽  
Dynamic Behaviour ◽  
Dynamic Properties ◽  
Body Height ◽  
Stick Insect ◽  
Open Loop ◽  
Carausius Morosus ◽  
Height Control

The properties of the system that controls the distance between body and ground was investigated in the stick insect Carausius morosus. The insect walked on a lightweight double treadwheel under open-loop or closed-loop conditions. The open-loop investigations show that the dynamic behaviour of the height-control system in the walking animal can be described in terms of a simple proportional system with negligible dynamic properties, and it is therefore much simpler than the height-control system in the standing animal. Under open-loop conditions, we found no coupling between contralateral or ipsilateral legs. This agrees with the findings on standing animals. The force- height characteristic shows two ranges, in each of which the system exhibits a linear relationship but a different slope. Under closed-loop conditions, the force-height characteristic shows the same two linear ranges, but the slopes are greater than under open-loop conditions. Because the height controller of each leg can be considered to act like a spring, this result means that under closed-loop conditions the controller is stiffer than it is under open-loop conditions.

A Biological Feedback Control System with Electronic Input: The Artificially Closed Femur-Tibia Control System of Stick Insects

1986 ◽  
Vol 120 (1) ◽  
pp. 369-385 ◽  
Author(s):  
G. WEILAND ◽  
U. BÄSSLER ◽  
M. BRUNNER
Keyword(s):  
Control System ◽  
Feedback Control ◽  
Closed Loop ◽  
Stick Insect ◽  
Open Loop ◽  
Loop System ◽  
Chordotonal Organ ◽  
Closed Loop System ◽  
Open Loop System ◽  
Stick Insects

An experimental arrangement was constructed which is based on the open-loop femur-tibia control system of two stick insect species (Carausius morosus and Cuniculina impigra). It could be artificially closed in the following way: the position of the tibia was measured by an optical device and this value was used to drive a penmotor which moved the receptor apodeme of the femoral chordotonal organ in the same way as in intact animals. This arrangement allows direct comparison of the behaviour of the open-loop and the closed-loop system as well as introducing an additional delay. The Carausius system has a phase reserve of only 30°-50° and the factor of feedback control approaches 1 between 1 and 2 Hz. This agrees with the observation that an additional delay of 70–200 ms produces long-lasting oscillations of 1–2 Hz. The Cuniculina system has a larger phase reserve and consequently a delay of 200 ms produced no oscillations. All experiments show that extrapolation from the open-loop system to the closed-loop system is valid, despite the non-linear characteristics of the loop. Consequences for servo-mechanisms during walking and rocking movements are discussed.

Tangible Programming for Basic Control System New Frameworks to Engineering Education for Children

2014 ◽  
Vol 931-932 ◽  
pp. 1298-1302
Author(s):  
Thiang Meadthaisong ◽  
Siwaporn Meadthaisong ◽  
Sarawut Chaowaskoo
Keyword(s):  
Control System ◽  
Engineering Education ◽  
Control Systems ◽  
Primary Schools ◽  
Closed Loop ◽  
Open Loop ◽  
Closed Loop Control ◽  
College Level ◽  
Loop Control ◽  
Tangible Programming

Programming control in industrial design is by its nature expert upon an example being Programmable Logic Controller (PLC). Such programmes are unsuitable for children or novices as they cannot understand how to use the programme. This research seeks to present tangible programming for a basic control system in new frameworks in engineering education for children. Such programmes could be for use in kindergartens, primary schools or general teaching where knowledge about basic control is required. Normally open-loop and closed-loop control system programming is taught at university and college level. This may be late as far as acquiring knowledge of basic control systems is concerned. Using tangible programming without a computer but instructions and interface, relay and motor could result in children in kindergartens and primary schools being able to programme open-looped control systems which mix chemicals or closed-loop control systems which control conveyor belts. However, the children would not be able to undertake programming using programmable control in a similar scenario.

Open Loop and Closed Loop Performance of Solid Oxide Fuel Cell Turbine Hybrid Systems During Fuel Composition Changes

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Nor Farida Harun ◽  
David Tucker ◽  
Thomas A. Adams
Keyword(s):  
Control System ◽  
Fuel Cell ◽  
Closed Loop ◽  
Open Loop ◽  
Solid Oxide ◽  
Fuel Composition ◽  
Oxide Fuel ◽  
Thermal Effluent ◽  
Turbine Speed ◽  
Composition Changes

The dynamic behavior of a solid oxide fuel cell gas turbine hybrid system (SOFC/GT) from both open and closed loop transients in response to sudden changes in fuel composition was experimentally investigated. A pilot-scale (200–700 kW) hybrid facility available at the U.S. Department of Energy, National Energy Technology Laboratory was used to perform the experiments using a combination of numerical models and actual equipment. In the open loop configuration, the turbine speed was driven by the thermal effluent fed into the gas turbine system, where the thermal effluent was determined by the feedforward fuel cell control system. However, in the closed loop configuration, a load-based speed control system was used to maintain the turbine speed constant at 40,500 rpm by adjusting the load on the turbine, in addition to the implementation of the fuel cell system control. The open loop transient response showed that the impacts of fuel composition changes on key process variables, such as fuel cell thermal effluent, turbine speed, and cathode feed stream conditions, in the SOFC/GT systems were propagated over the course of the test, except for the cathode inlet temperature. The trajectories of the aforementioned variables are discussed in this paper to better understand the resulting mitigation/propagation behaviors. This will help lead to the development of novel control strategies to mitigate the negative impacts experienced during fuel composition transients of SOFC/GT systems.

Control System Synthesis Based on Plant Test Data

1995 ◽  
Vol 117 (4) ◽  
pp. 484-489
Author(s):  
Jenq-Tzong H. Chan
Keyword(s):  
Control System ◽  
Test Data ◽  
Closed Loop ◽  
Explicit Knowledge ◽  
Linear Time ◽  
Open Loop ◽  
Loop System ◽  
Closed Loop System ◽  
System Synthesis ◽  
Control System Synthesis

A correlation equation is established between open-loop test data and the desired closed-loop system characteristics permitting control system synthesis to be done on the basis of a numerical approach using experimental data. The method is applicable when the system is linear-time-invariant and open-loop stable. The major merits of the algorithm are two-fold: 1) Arbitrary placement of the closed-loop system equation is possible, and 2) explicit knowledge of an open-loop system model is not needed for the controller synthesis.

Experimental Study of Landing Gear Simulation Test-Bed

2014 ◽  
Vol 1030-1032 ◽  
pp. 1181-1184
Author(s):  
Miao Shang ◽  
Guo Min Lin ◽  
Wen Guang Zhang ◽  
Fei Zhou
Keyword(s):  
Control System ◽  
Closed Loop ◽  
Test System ◽  
Open Loop ◽  
Landing Gear ◽  
Test Bed ◽  
Simulation Test ◽  
Loop Control ◽  
System Experiment ◽  
Loop Control System

The basic composition of the landing gear simulator test-bed is discussed; The open loop control system experiment, closed-loop light control system experiment, the closed loop load control system are completed for the test system; The reliability and stability of test-bed system are validated by the experiment; The technical indexes of the landing gear simulation test-bed and the design requirement of electric control system are validated.

scholarly journals Fundamental Limits in Combine Harvester Header Height Control

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Yangmin Xie ◽  
Andrew G. Alleyne ◽  
Ashley Greer ◽  
Dustin Deneault
Keyword(s):  
Closed Loop ◽  
Open Loop ◽  
The Other ◽  
Specific System ◽  
Fundamental Limits ◽  
Height Control ◽  
Sensor Actuator ◽  
Loop Transfer Function ◽  
Loop Bandwidth ◽  
Combine Harvester

This paper investigates fundamental performance limitations in the control of a combine harvester's header height control system. There are two primary subsystem characteristics that influence the achievable bandwidth by affecting the open loop transfer function. The first subsystem is the mechanical configuration of the combine and header while the second subsystem is the electrohydraulic actuation for the header. The mechanical combine + header subsystem results in an input–output representation that is underactuated and has a noncollocated sensor/actuator pair. The electrohydraulic subsystem introduces a significant time delay. In combination, they each reinforce the effect of the other thereby exacerbating the overall system limitation of the closed loop bandwidth. Experimental results are provided to validate the model and existence of the closed loop bandwidth limitations that stem from specific system design configurations.

scholarly journals The Control System of the Femur-Tibia Joint in the Standing Leg of a Walking Stick Insect Carausius Morosus

1983 ◽  
Vol 102 (1) ◽  
pp. 175-185 ◽  
Author(s):  
H. CRUSE ◽  
J. SCHMITZ
Keyword(s):  
Control System ◽  
Stick Insect ◽  
The State ◽  
Alternative States ◽  
Carausius Morosus ◽  
Generalized System ◽  
System Changes ◽  
Walking Stick

The control system of the femur-tibia joint of the stick insect (Carausius tnorosus) shows different properties depending on whether the animal is standing or walking. The properties of the system were examined when the animal was walking on a treadwheel and when the examined leg rested on a platform fixed beside the wheel. The results show that the properties of the system in the standing leg of a walking animal are similar to those of a walking animal rather than those of the standing animal. This indicates that the state of the leg (standing or walking) does not seem to be controlled by the neural subsystem of the leg itself but by a more generalized system, which differs in its properties depending upon whether the whole animal is standing or walking. Furthermore the results show how the behaviour of the system changes for the two alternative states.

Open Loop and Closed Loop Performance of Solid Oxide Fuel Cell Turbine Hybrid Systems During Fuel Composition Changes

2015 ◽  
Author(s):  
Nor Farida Harun ◽  
David Tucker ◽  
Thomas A. Adams
Keyword(s):  
Control System ◽  
Fuel Cell ◽  
Closed Loop ◽  
Open Loop ◽  
Solid Oxide ◽  
Fuel Composition ◽  
Oxide Fuel ◽  
Thermal Effluent ◽  
Turbine Speed ◽  
Composition Changes

The dynamic behavior of a solid oxide fuel cell gas turbine hybrid system (SOFC/GT) from both open and closed loop transients in response to sudden changes in fuel composition was experimentally investigated. A pilot-scale (200kW – 700kW) hybrid facility available at the U.S. Department of Energy, National Energy Technology Laboratory was used to perform the experiments using a combination of numerical models and actual equipment. In the open loop configuration, the turbine speed was driven by the thermal effluent fed into the gas turbine system, where the thermal effluent was determined by the feedforward fuel cell control system. However, in the closed loop configuration, a load-based speed control system was used to maintain the turbine speed constant at 40,500rpm by adjusting the load on the turbine, in addition to the implementation of the fuel cell system control. The open loop transient response showed that the impacts of fuel composition changes on key process variables, such as fuel cell thermal effluent, turbine speed and cathode feed stream conditions in the SOFC/GT systems were propagated over the course of the test, except for the cathode inlet temperature. The trajectories of the aforementioned variables are discussed in this paper to better understand the resulting mitigation/propagation behaviors. This will help lead to the development of novel control strategies to mitigate the negative impacts experienced during fuel composition transients of SOFC/GT systems.

Correlation between muscle structure and filter characteristics of the muscle-joint system in three orthopteran insect species

1996 ◽  
Vol 199 (10) ◽  
pp. 2169-2183 ◽  
Author(s):  
D Bässler ◽  
A Büschges ◽  
S Meditz ◽  
U Bässler
Keyword(s):  
Control System ◽  
Locusta Migratoria ◽  
Open Loop ◽  
Corner Frequency ◽  
Joint Control ◽  
Muscle Fibres ◽  
Joint System ◽  
Carausius Morosus ◽  
Muscle Structure ◽  
Stimulation Of

In orthopteran insects, neural networks for joint control exhibit different characteristics due to behavioural specializations. We investigated whether these differences are generated purely by the neuronal networks, or whether characteristics of the muscles or joint architecture (muscle­joint system) are also involved in these behavioural specializations. We compared the properties of the muscle system moving the femur­tibia joint of the middle and hindleg of three species, Carausius morosus, Cuniculina impigra and Locusta migratoria. Four aspects were analysed for the tibial extensor muscle: (i) the frequency-dependence of motoneuronal activity in response to sinusoidal stimulation of the femoral chordotonal organ (fCO), (ii) the muscle structure, (iii) the innervation pattern of the muscle and (iv) the histochemical properties of the muscle fibres. These aspects were compared with the filter characteristics of the open-loop femur­tibia control system and of the muscle­joint system involved. Whereas in both phasmid species (Carausius morosus and Cuniculina impigra) the motoneuronal activity steadily increases with sinusoidal stimulation of the fCO in the frequency range 0.01­5 Hz, in Locusta migratoria there is a decrease in motoneuronal activity between 0.01 and 0.3 Hz. The muscle structure is basically similar in all three species, as the number of singly innervated muscle fibres (supplied by the fast extensor tibiae motor neurone, FETi) decreases from proximal to distal. The number of triply innervated fibres supplied by the FETi, the slow extensor tibiae (SETi) and the common inhibitor 1 (CI1) is maximal in the middle of the muscle, and the number of dually innervated fibres (supplied by SETi, CI1) increases from proximal to distal. Differences between the locust and the two phasmid species exist in the distal portion of the muscle. The phasmid extensor tibiae muscle contains a morphologically distinct bundle of muscle fibres, not present in the locust, which is mostly dually innervated and which is larger in Cuniculina impigra. Similar results were obtained for the histochemical characterisation of the muscle fibres as revealed from their staining for myofibrillar ATPase activity. The number of histochemically identified fast fibres decreased from proximal to distal, while the number of slow fibres increased. In Carausius morosus and Locusta migratoria, the percentage of slow fibres increased by up to 60­70 % at the distal end, while this increase was to almost 100 % in Cuniculina impigra. Apparently, the larger this distal region and the higher the percentage of slow, dually innervated fibres in it, the lower is the upper corner frequency (the stimulus frequency at which the joint control system produces a movement with 70 % of its maximal response amplitude) of the muscle­joint system. In summary, it appears that the upper corner frequency of the open-loop system in Locusta migratoria (<0.05 Hz) results at least in part from properties of the neuronal joint control network, but in Carausius morosus (0.5­1.0 Hz) and Cuniculina impigra (0.1­0.2 Hz) it results from the upper corner frequency of the muscle­joint system.

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