关键词: 运载火箭, 姿态控制, 减载控制, 弹性振动, 干扰抑制, 自抗扰控制, 飞行实验

Abstract: The load relief control of launch vehicles reduces aerodynamic loads by decreasing the angle of attack. However, ex-isting active disturbance rejection control (ADRC) methods for load relief do not fully account for elastic effects, which may lead to reduced disturbance estimation accuracy and even compromise system stability. To address this, this paper analyzes the impact of elastic vibration on disturbance estimation and observer gain, and proposes an im-provement to suppress elastic vibration. By isolating elastic motion from rigid-body motion, the measured input of the extended state observer (ESO) is made to match the observation model, thereby reducing the influence of elasticity on disturbance estimation. Based on this, the open-loop transfer function of the active disturbance rejection load relief control system considering elastic vibration is derived, and a set of parameter tuning rules is provided. By properly configuring the bandwidths of the load relief feedback control and the ESO, the tuning process is simplified while ensuring sufficient stability margins. Simulation and experimental results demonstrate that this method enhances system stability while achieving effective disturbance suppression and load relief. Finally, the algorithm's feasibility was vali-dated through hardware-in-the-loop simulations and flight tests on a rocket.

Key words: launch vehicle, attitude control, load relief control, elastic vibration, disturbance rejection, active disturbance rejection control, flight experiment.