FIR Systems Identification Under Quantized Output Observations and a Large Class of Persistently Exciting Quantized Inputs

This paper investigates the FIR systems identification with quantized output observations and a large class of quantized inputs. The limit inferior of the regressors' frequencies of occurrences is employed to characterize the input's persistent excitation, under which the strong convergence and the convergence rate of the two-step estimation algorithm are given. As for the asymptotical efficiency,with a suitable selection of the weighting matrix in the algorithm, even though the limit of the product of the Cram′er-Rao(CR) lower bound and the data length does not exist as the data length goes to infinity, the estimates still can be asymptotically efficient in the sense of CR lower bound. A numerical example is given to demonstrate the effectiveness and the asymptotic efficiency of the algorithm.

Robust Adaptive Attitude Control for Non-rigid Spacecraft With Quantized Control Input

In this paper,an adaptive backstepping control scheme is proposed for attitude tracking of non-rigid spacecraft in the presence of input quantization,inertial uncertainty and external disturbance.TThe control signal for each actuator is quantized by sector-bounded quantizers,including the logarithmic quantizer and the hysteresis quantizer.By describing the impact of quantization in a new affine model and introducing a smooth function and a novel form of the control signal,the influence caused by input quantization and external disturbance is properly compensated for.Moreover,with the aid of the adaptive control technique,our approach can achieve attitude tracking without the explicit knowledge of inertial parameters.Unlike existing attitude control schemes for spacecraft,in this paper,the quantization parameters can be unknown,and the bounds of inertial parameters and disturbance are also not needed.In addition to proving the stability of the closed-loop system,the relationship between the control performance and design parameters is analyzed.Simulation results are presented to illustrate the effectiveness of the proposed scheme.

Quantized Formation Control of Heterogeneous Nonlinear Multi-Agent Systems with Switching Topology

This paper studies the formation control problem for the second-order heterogeneous nonlinear multi-agent systems(MASs)with switching topology and quantized control inputs.Compared with formation control under the fixed topology,under the switching topology inherent nonlinear dynamics of the agent and the connectivity change of the communication topology are considered.Moreover,to avoid the chattering phenomenon caused by unknown input disturbances,the hysteretic quantizers are incorporated to quantize the input signals.By using the Lyapunov stability theory and leader-follower formation approach,the proposed formation control scheme ensures that all signals of the MASs are semi-globally uniformly ultimately bounded(SGUUB).Finally,the efficiency of the theoretical results is proved by a simulation example.