Doğrusal mantık uslamlamasının sürekli kısıtlar varlığında kullanımı ile dinamik robotlarda otonom davranış progralaması

TÜBİTAK EEEAG Proje01.03.201

Küresel tekerlekli mobil robotlarda denge, yörünge kontrolü ve yol planlaması

Geleneksel tekerlekli mobil robotların insanların varolduğu ortamlarda rahat ve kıvrak bir şekilde hareketleri, ağır yapıları ve hızlı davranışlarda denge kaybı yaşama olasılıkları sebebiyle zorluklar içermektedir. Bu kapsamdaki problemleri çözebilmek için yakın geçmişte yeni bir hareketlilik biçimi olarak küresel bir tekerlek üzerinde kendilerini dengeleyen Ballbot robot platformları öne sürülmüştür. Bu platformlar holonomik olmayan dinamikleri ve tamamı doğrudan kontrol edilemeyen serbestlik dereceleri sebebiyle bünyelerinde çözülmemiş birçok bilimsel problemi barındırmaktadır. Bu proje kapsamında bu tür platformların üç boyutta yeterli hassasiyette modelleri geliştirilecek, tasarlanıp yapılacak olan deneysel bir platform üzerinde bu modelin doğrulamasına başlanılarak model tabanlı hassas hareket ve kontrol planlama algoritmaları için gerekli zemin hazırlanacaktır. Proje sonucunda çalışır bir Ballbot platformu vebuna uygulanabilecek bir modelin ortaya çıkması beklenmektedir

Hybrid sol-gel conducting polymer synthetised by electrochemical insertion: tailoring the capacitance of polyaniline

The templated growth of polyaniline through porous sol–gel films on ITO substrates has been performed. The polyaniline–silica composites have been synthesized by electrochemical reactive insertion in potentiodynamic and potentiostatic conditions. When the polymer is synthesized by potential step experiments, the shape of the chronoamperograms indicates two regimes for the electrochemical polymerization of PANI. Electropolymerization happens faster within the silica pores than on bare ITO electrodes due to confinement effects of oligomeric species formed upon oxidation. The electrochemical capacitance of the silica–PANI hybrids is several time higher than the capacitance of ITO/PANI synthesized under the same conditions. The silica matrix avoids the electric collapse between vicinal conducting fibres in ITO/silica–PANI but allows the diffusion of ionic species that are in contact with the conjugated polymer, increasing therefore the conducting surface exposed to the electrolytic solution.This work was financed by the following projects: MAT2007-60621 of the Spanish Ministerio de Ciencia e Innovación and GVPRE/2008/249 of the Generalitat Valenciana

Estimation of Ground Reaction Forces Using Low-Cost Instrumented Forearm Crutches

Instrumented crutches are useful for many rehabilitation tasks, including monitoring the correctness of crutch use, analyzing gait properties for patients with lower-limb impairments, as well as providing sensory data for controlling lower-body robotic orthoses. In this paper, we describe the design and analysis of an instrumented crutch system equipped with low-cost accelerometer and pressure sensors to estimate all components of the ground reaction force (GRF), providing a well-defined and physically meaningful sensory output for practical applications. We propose an angle-dependent quadratic model to map pressure and inclination data to force components, which we identify using least-squares methods. Through systematic characterization experiments, we first show that our model can predict GRF vectors with less than 7% rms errors in all axes for fixed crutch angles used for training. Subsequently, we generalize the model to crutch angles other than those used for training, showing that rms estimation errors remain below 7% for all axes. Finally, we assess measurement accuracy and performance under dynamic loading conditions with time-varying crutch angles, showing that errors still remain below 8% under realistic conditions

Control of Planar Spring-Mass Running Through Virtual Tuning of Radial Leg Damping

Existing research on dynamically capable legged robots, particularly those based on spring-mass models, generally considers improving in isolation either the stability and control accuracy on the rough terrain, or the energetic efficiency in steady state. In this paper, we propose a new method to address both, based on the hierarchical embedding of a simple spring-loaded inverted pendulum (SLIP) template model with a tunable radial damping coefficient into a realistic leg structure with series-elastic actuation. Our approach allows using the entire stance phase to inject/remove energy both for transient steps and in steady state, decreasing the maximum necessary actuator power while eliminating wasteful sources of the negative work. In doing so, we preserve the validity of the existing analytic approximations to the underlying SLIP model, propose improvements to increase the predictive accuracy, and construct accurate, model-based controllers that use the tunable damping coefficient of the template model. We provide extensive comparative simulations to establish the energy and power efficiency advantages of our approach, together with the accuracy of model-based gait control methods

Reactive Planning and Control of Planar Spring-Mass Running on Rough Terrain

An important motivation for work on legged robots has always been their potential for high-performance locomotion on rough terrain. Nevertheless, most existing control algorithms for such robots either make rigid assumptions about their environments or rely on kinematic planning at low speeds. Moreover, the traditional separation of planning from control often has negative impact on the robustness of the system. In this paper, we introduce a new method for dynamic, fully reactive footstep planning for a planar spring-mass hopper, based on a careful characterization of the model dynamics and the design of an associated deadbeat controller, used within a sequential composition framework. This yields a purely reactive controller with a large domain of attraction that requires no explicit replanning during execution. We show in simulation that plans constructed for a simplified dynamic model can successfully control locomotion of a more complete model across rough terrain. We also characterize the performance of the planner over rough terrain and show that it is robust against both model uncertainty and measurement noise without replanning

Quadrupedal Bounding with an Actuated Spinal Joint

Most legged vertebrates use flexible spines and supporting muscles to provide auxiliary power and dexterity for dynamic behaviors, resulting in higher speeds and additional maneuverability during locomotion. However, most existing legged robots capable of dynamic locomotion incorporate only a single rigid trunk with actuation limited to legs and associated joints. In this paper, we investigate how quadrupedal bounding can be achieved in the presence of an actuated spinal joint and characterize associated performance improvements compared to bounding with a rigid robot body. In the context of both a new controller structure for bounding with a body joint and existing bounding controllers for the rigid trunk, we use optimization methods to identify the highest performance gait parameters and establish that the spinal joint allows increased forward speeds and hopping heights

Robotic task planning using a backchaining theorem prover for multiplicative exponential first-order linear logic

In this paper, we propose an exponential multiplicative fragment of linear logic to encode and solve planning problems efficiently in STRIPS domain, that we call the Linear Planning Logic (LPL). Linear logic is a resource aware logic treating resources as single use assumptions, therefore enabling encoding and reasoning of domains with dynamic state. One of the most important examples of dynamic state domains is robotic task planning, since informational or physical states of a robot include non-monotonic characteristics. Our novel theorem prover is using the backchaining method which is suitable for logic languages like Lolli and Prolog. Additionally, we extend LPL to be able to encode non-atomic conclusions in program formulae. Following the introduction of the language, our theorem prover and its implementation, we present associated algorithmic properties through small but informative examples. Subsequently, we also present a navigation domain using the hexapod robot RHex to show LPL's operation on a real robotic planning problem. Finally, we provide comparisons of LPL with two existing linear logic theorem provers, llprover and linTAP. We show that LPL outperforms these theorem provers for planning domains.Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) (114E277)Publisher's Versio

Template based control of hexapedal running

In this paper, we introduce a hexapedal locomotion controller that simulation evidence suggests will be capable of driving our RHex robot at speeds exceeding five body lengths per second with reliable stability and rapid maneuverability. We use a low dimensional passively compliant biped as a "template"-a control target for the alternating tripod gait of the physical machine. We impose upon the physical machine an approximate inverse dynamics within-stride controller designed to force the true high dimensional system dynamics down onto the lower dimensional subspace corresponding to the template. Numerical simulations suggest the presence of asymptotically stable running gaits with large basins of attraction. Moreover, this controller improves substantially the maneuverability and dynamic range of RHex's running behaviors relative to the initial prototype open-loop algorithms