Structurally decoupled control for vibration suppression and bandwidth enhancement in flexible ball screw feed drive systems

Most existing control strategies for flexible ball screw feed drive systems (BSFDS) either rely on complex structures and extensive parameter adjustments to achieve vibration suppression and enhanced bandwidth, or maintain the conventional proportional–proportional–integral (P–PI) framework while grappling with significant parameter coupling between auxiliary compensators and the baseline controller. This study develops a structurally decoupled control approach for BSFDS operating within a P–PI full closed-loop architecture, aiming to suppress vibration and improve bandwidth performance by mathematically decoupling the velocity and position loop transfer functions. The analysis identifies that vibration mode and bandwidth limitations primarily stem from the flexibility in the velocity loop, while the flexibility-induced residual response in the position loop further restricts achievable bandwidth. Based on these findings, a shaping controller is integrated into the PI-controlled velocity loop. This controller employs structurally decoupled parameterization, with its parameters uniquely determined by the system’s anti-resonance frequency and damping ratio. These settings are independent of the PI gains, effectively transforming the velocity loop into an equivalent second-order system with adjustable bandwidth characteristics. Building on this foundation, a position difference-based residual flexible-response compensation controller has been incorporated into the position loop to further extend the achievable bandwidth. Experimental results demonstrate the validity and effectiveness of the proposed approach.