仿生六足机器人虚拟模型控制

论文针对仿生六足机器人运动问题,提出了一种基于虚拟模型控制(Virtual Model Control,VMC)的简单直观的运动控制方法。在VMC框架中,一系列虚拟原件安装在机器人关节上,以产生相应的虚拟力。将机器人腿的运动模式分为站立相和摆动相两个阶段。站立相中,VMC被用于控制机器人躯干姿态,包括躯干高度和欧拉角;摆动相中,VMC为摆动腿提供控制,使其遵循期望的轨迹。通过状态机实现机器人腿状态切换和运动配合。仿真结果表明,设计的控制器可以实现六足机器人三角步态稳定行走。

TTE网络测试系统设计与实现

TTE网络协议增强了传统以太网传输的网络确定性,时间同步以及非阻塞等网络性能,可将不同时间关键程度的业务集中在同一网络。根据TTE网络协议,实现了一种混合业务传输的网络系统,针对该系统的特性,开展了符合协议验证技术的研究,设计了一套平台测试系统架构,从同步机制、数据传输、错误帧识别三个关键方面提出此混合业务TTE网络平台的测试用例,并给出了详细的测试方法。此测试系统的设计对TTE自动化网络测试设备的研究设计提供了有力的支撑。

以石墨烯气凝胶为导电相的压电阻尼复合材料

阻尼材料在减振降噪领域有着极其重要的应用,而压电阻尼复合材料能够在普通阻尼材料摩擦损耗基础之上进一步引入力-电-热损耗,从而提高基体材料的阻尼性能,使其在主动和被动减震方面备受青睐。但是通常为了达到导电渗流阈值,需要添加大量的导电相。采用模板辅助氧化石墨烯自组装的方式制备了三维石墨烯气凝胶,以此作为导电相,以聚氨酯/聚甲基丙烯酸丁酯/聚甲基丙烯酸甲酯IPN共聚物作为基体,锆钛酸铅压电陶瓷作为压电相,制备了压电阻尼复合材料。三维石墨烯气凝胶的使用,由于其本身三维导电网络的存在,使得制备的压电阻尼复合材料可以在很低的导电相含量下达到导电渗流阈值,将压电陶瓷产生的电能转化为热能损耗掉,有效拓宽了基体材料的阻尼温域和提高了材料室温下的阻尼性能。

混合制冷剂对于冰箱节能和冷量优化的影响

冰箱作为家庭常用且持续运行的家用电器之一,在居民生活用电占有很大的比例。在中国2030年实现碳达峰,2060年实现碳中和背景下,冰箱节能具有重要的意义。同时,人们对于食品保鲜的要求也越来越高,冷冻储藏温度越来越低。为满足更加低温、更大冷量、更低电量的需求,对比了R600a、R290及其混合制冷剂的冷量、消耗功率、COP,发现在R600a中引入合适比例的R290可以优化系统的整体COP,增大冷量,更好地满足用户需求。

运载火箭动力着陆段制导控制方法综述与展望

可重复使用运载火箭能够大幅降低进入空间的成本,是下一代航天运输系统的重要组成部分,而动力着陆段是实现可重复使用运载火箭回收的关键。对现有运载火箭动力着陆段的制导控制方法进行了综述,在对现有方法进行分析的基础上提出了一种模块化协作设计,并对人工智能方法在制导控制中的应用进行了展望。首先建立了运载火箭动力着陆段制导控制的整体模型,归纳了常用指标及约束集合,并分析了制导控制设计需解决的问题。然后,对现有的主要制导控制方法,即解析制导方法、轨迹优化制导方法、基于机器学习的制导方法、姿态控制方法及制导控制协作方法等进行了综述,通过分析所考虑的运动方程模型、约束及性能指标等对主要方法进行了较全面的比较,并进一步针对不确定模型及干扰下的制导控制综合目标优化问题提出了一种模块化智能协作方法。最后,对动力着陆段制导控制方法的发展趋势进行了总结,并对人工智能方法与动力着陆段制导控制方法的结合进行了展望。

On distributed Kalman filter based state estimation algorithm over a bearings-only sensor network

This paper studies the distributed state estimation problem for a class of discrete-time linear time-varying systems over a bearingsonly sensor network.A novel fusion estimation algorithm of the distance between the target and each sensor is constructed with the mean square error matrix of corresponding estimation being timely provided.Then,the refined estimation of distance is presented by minimizing the mean square error matrix.Furthermore,the distributed Kalman filter based state estimation algorithm is proposed based on the refined distance estimation.It is rigorously proven that the proposed method has the consistency and stability.Finally,numerical simulation results show the effectiveness of our methods.

On Hierarchical Compensation Based Active Disturbance Rejection Control for ACMM Problem of Spacecraft

The attitude control and momentum management(ACMM)problem is quite fundamental for many spacecrafts including space stations,sky laboratories and etc.Instead of single attitude control problem,ACMM problem has to take account of both disturbance rejection and energy optimization.This paper studies the ACMM problem for general spacecraft.A practical active disturbance rejection control architecture is proposed with hierarchical compensation to different kinds of uncertain dynamics or disturbances.In particular,by integrating RLS into ESO,the constant and sinusoidal disturbance terms to be compensated are reconstructed.Also,the LQR law is implemented to achieve the desired performance of control systems after disturbance compensation.Furthermore,quantitative performances of the generalized ESO,the RLS algorithm and the closed-loop tracking system are rigorously analyzed.Finally,the results under 9-DOF semi-physical test environment show the effectiveness of our control method.

On Designing Consistent Extended Kalman Filter

This paper studies the consistency of the extended Kalman filter(EKF) for a kind of nonlinear systems. Based on the EKF algorithm, the authors propose the quasi-consistent EKF(QCEKF)as well as the tuning law for its parameters. The quasi-consistency of the proposed algorithm is proved.Finally, the feasibility of the algorithm is illustrated by the numerical simulation on an orbit determination example.

Tuning of Sampled-Data ADRC for Nonlinear Uncertain Systems

This paper concerns with the parameters tuning of active disturbance rejection control(ADRC) for a class of nonlinear systems with sampling rate not fast enough. The theoretical results show the quantitative relationship between the sampling rate, the parameters of ADRC, the size of uncertainties in system and the properties of the closed-loop system. Furthermore, the capability of the sampled-data ADRC under given sampling rate is quantitatively discussed.

Radar Target Recognition Algorithm Based on RCS Observation Sequence——Set-Valued Identification Method

This paper studies the problem of radar target recognition based on radar cross section(RCS)observation sequence.First,the authors compute the discrete wavelet transform of RCS observation sequence and extract a valid statistical feature vector containing five components.These five components represent five different features of the radar target.Second,the authors establish a set-valued model to represent the relation between the feature vector and the authenticity of the radar target.By set-valued identification method,the authors can estimate the system parameter,based on which the recognition criteria is given.In order to illustrate the efficiency of the proposed recognition method,extensive simulations are given finally assuming that the true target is a cone frustum and the RCS of the false target is normally distributed.The results show that the set-valued identification method has a higher recognition rate than the traditional fuzzy classification method and evidential reasoning method.

Active Disturbance Rejection Control for PMLM Servo System in CNC Machining

Uncertain friction is a key factor that influences the accuracy of servo system in CNC machine.In this paper,based on the principle of Active Disturbance Rejection Control(ADRC),a control method is proposed,where both the extended state observer(ESO) and the reduced order extended state observer(RESO) are used to estimate and compensate for the disturbance.The authors prove that both approaches ensure high accuracy in theory,and give the criterion for parameters selection.The authors also prove that ADRC with RESO performs better than that with ESO both in disturbance estimation and tracking error.The simulation results on CNC machine show the effectiveness and feasibility of our control approaches.

Longitudinal Control for Balloon-Borne Launched Solar Powered UAVs in Near-Space

Aiming to improve the pull-up control performance in the process of releasing balloonborne solar powered UAVs(Unmanned Aerial Vehicles),this paper establishes the full flight mechanics equations with flexible modes,and proposes the control method suitable for engineering application.To be specific,the authors first calculate the real aerodynamic force on horizontal stabilizer by comparing the fuselage deformation in ballooning test with that in static loading test.Furthermore,considering fuselage elastic deformation,the pitching moment coefficient is obtained and the influence of airspeed and elevator angle on pitching moment coefficient and control surface efficiency are analysed.Second,the authors establish a complete flight mechanics model,including elastic structural dynamic model and rigid flight dynamic model,by comprehensively considering the aerodynamic data,the relationship between fuselage deformation and load,as well as the ballooning test.Third,the authors perform the numerical simulation and comparison study on control performance between rigid model and flexible model.Moreover,the authors implement model modification based on the low altitude flight test and steady-state point analysing.Finally,a scaled UAV is used to complete the balloon-borne launching test.The results show that the longitudinal control method can analyse the longitudinal aerodynamics and control characteristics accurately,and could be effectively utilized in the pull-up control of the balloon-borne solar powered UAV.