# Real-Time Tracking and Position Control of an Elastic Cable-Driven Winch System
###### Abstract  
This study explores the sliding mode control (SMC) strategy to address challenges such as nonlinear dynamics, steady-state errors, and torque fluctuations in elastic cable-driven winch systems. While traditional Proportional-Derivative (PD) control is sufficient for linear systems, it struggles with instability and accuracy issues in flexible systems. SMC provides robustness against uncertainties but can cause mechanical wear and performance degradation due to its chattering effect. To mitigate this, a continuous control signal-based SMC approach was adopted, reducing chattering and improving system stability. This study focuses on tracking and position control, as well as managing motor torque fluctuations during position control, emphasizing controller parameter optimization. Experimental results demonstrate that SMC outperforms PD control in tracking, position control, and torque management. elastic cable-driven system; sliding mode control; real-time control; torque ripple 20251546202  
the rope is often assumed to be non-extensible. Research on elevator systems has focused on longitudinal vibrations, and the equations of motion have been derived using [PERSON]'s principle and subsequently converted into ordinary differential equations through the Galerkin method. Methods such as Lyapunov control have dissipated vibrational energy in these models [11]. [PERSON] et al. [12] demonstrated that the rope parameters, such as time-varying stiffness, damping constant, and rope mass, evolve. Therefore, measuring the load position is crucial for load position control during vertical movements. Furthermore, [PERSON] et al. developed a simple mathematical model for a nonlinear elastic cable winch system. They applied input-output feedback linearization theory to control winch movement without requiring load position information [13]. The sliding mode control (SMC) method has emerged as a preferred control strategy for such nonlinear systems due to its robustness against varying parameters and external disturbances [14]. To mitigate the phenomenon known as \"chattering,\" which manifests as high-frequency oscillations in the control signal, the Equivalent Sliding Mode Control (ESMC) method has been employed, ensuring system stability against external effects [15; 16; 17]. For instance, the dynamics of nonlinear plants have been analyzed using ESMC, demonstrating simplified stability proofs [18]. Additionally, integrating SMC with the equivalent input disturbance approach has enhanced disturbance rejection capabilities in Stewart platform control systems [19]. In the study conducted by [PERSON] et al., the Global Equivalent Sliding Mode Control (GESMC) method was shown through simulations to provide faster and more stable performance with less chattering compared to conventional sliding mode control (SMC) and PID control in bridge crane systems [20]. Similarly, [PERSON] et al. applied a Disturbance Evaluating Sliding Mode Control (DESMC) method to a four-degree-of-freedom tower crane system, incorporating the beneficial aspects of disturbance effects into the control design, thereby achieving superior control performance as demonstrated in simulations [21]. In this context, the present study advances beyond the simulation studies in [20; 21] by analyzing the real-time performance of SMC approaches. The study by [PERSON] and [PERSON] implemented a super-twisting algorithm-based SMC approach in tower cranes, achieving vibration suppression and precise control while offering high robustness against external disturbances [22]. Likewise, [PERSON] et al. designed a variable structure sliding mode controller for bridge cranes to suppress load oscillations and achieve precise positioning, effectively reducing chattering in the control input [23]. Furthermore, the work by [PERSON] et al. introduced a hybrid integral sliding mode control scheme for cable-driven parallel robots, improving tracking accuracy and mitigating vibration issues [24].