Simeon Nedelchev


    Nedelchev S., Kozlov L., Khusainov R. R., Gaponov I.
    Adaptive control and parameter estimation have been widely employed in robotics to deal with parametric uncertainty. However, these techniques may suffer from parameter drift, dependence on acceleration estimates and conservative requirements for system excitation. To overcome these limitations, composite adaptation laws can be used. In this paper, we propose an enhanced composite adaptive control approach for robotic systems that exploits the accelerationfree momentum dynamics and regressor extensions to offer faster parameter and tracking convergence while relaxing excitation conditions and providing a clear physical interpretation. The effectiveness of the proposed approach is validated through experimental evaluation on a 3-DoF robotic leg.
    Keywords: adaptive control, parameter estimation, motion control
    Citation: Nedelchev S., Kozlov L., Khusainov R. R., Gaponov I.,  Enhanced Adaptive Control over Robotic Systems via Generalized Momentum Dynamic Extensions, Rus. J. Nonlin. Dyn., 2023, Vol. 19, no. 4, pp.  633-646
    Fam C. A., Nedelchev S.
    This paper presents a control algorithm designed to compensate for unknown parameters in mechanical systems, addressing parametric uncertainty in a comprehensive manner. The control optimization process involves two key stages. Firstly, it estimates the narrow uncertainty bounds that satisfy parameter constraints, providing a robust foundation. Subsequently, the algorithm identifies a control strategy that not only ensures uniform boundedness of tracking error but also adheres to drive constraints, effectively minimizing chattering. The proposed control scheme is demonstrated through the modeling of a single rigid body with parameter uncertainties. The algorithm possesses notable strengths such as maximal compensation for parametric uncertainty, chattering reduction, and consideration of control input constraints. However, it is applicable for continuous systems and does not explicitly account for uncertainty in the control input.
    Keywords: optimization, sliding mode control, parametric uncertainty, stability
    Citation: Fam C. A., Nedelchev S.,  Optimization Driven Robust Control of Mechanical Systems with Parametric Uncertainties, Rus. J. Nonlin. Dyn., 2023, Vol. 19, no. 4, pp.  585-597

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