Active Magnetic Bearings (AMB) are mechatronic systems that support a rotating shaft using magnetic levitation. The standard AMB architecture includes two radial actuators and one for the axial direction. An alternative geometry with cone-shaped magnetic cores allows for a more compact layout without a dedicated axial actuator. However, this configuration reduces the axial force generation capability and requires a more complex control architecture due to the inherent coupling of the axial and radial control actions. When using decentralized control, effective handling of the coil current limitations together with the axial disturbance rejection is difficult to achieve. In this context, the present paper demonstrates the benefits of applying Offset-Free Model Predictive Control (OF-MPC) for a cone-shaped AMB system. A procedure for the overall design is presented and supported by the experimental work conducted in a scaled machine that reproduces an on-board turbo-compressor unit for an aircraft. The modeling of the system is described together with the design of the OF-MPC in all its parts: general control architecture, disturbance model and observer design, target calculation and control problem formulation. An OF-MPC variant with reduced control horizon is proposed and implemented in real time. Experimental results demonstrate that the prototype is compliant with application-specific stability requirements from the ISO 14839-3:2006 standard. In addition, experiments show that OF-MPC outperforms decentralized PID controllers in terms of axial disturbance rejection. OF-MPC yields a favorable constrained optimal control technique for cone-shaped AMBs because intrinsic coupling and current saturation are optimally handled by the controller.

主动磁轴承 (AMB) 是一种机电系统，它使用磁悬浮支撑旋转轴。标准 AMB 架构包括两个径向致动器和一个用于轴向方向。具有锥形磁芯的替代几何结构允许在没有专用轴向执行器的情况下实现更紧凑的布局。然而，由于轴向和径向控制动作的固有耦合，这种配置降低了轴向力生成能力，并且需要更复杂的控制架构。使用分散控制时，难以有效处理线圈电流限制和轴向干扰抑制。在此背景下，本文展示了将无偏移模型预测控制 (OF-MPC) 应用于锥形 AMB 系统的好处。整体设计的程序被提出并得到了在缩放机器中进行的实验工作的支持，该机器再现了飞机的机载涡轮压缩机单元。系统的建模与 OF-MPC 的所有部分的设计一起描述：一般控制架构、干扰模型和观测器设计、目标计算和控制问题公式化。提出并实时实施了一种具有减少控制范围的 OF-MPC 变体。实验结果表明，该原型符合 ISO 14839-3:2006 标准中针对特定应用的稳定性要求。此外，实验表明 OF-MPC 在轴向干扰抑制方面优于分散 PID 控制器。