垂直气动人工肌肉系统的模型参考自适应逆补偿控制

与传统刚性驱动系统相比, 气动人工肌肉系统具有质量轻、人机交互友好等优势, 近年来在生产生活中受到广泛关注. 然而, 该类系统的运动呈现出复杂的迟滞特性, 这给针对该类系统的跟踪控制研究带来了挑战. 本文针对垂直气动人工肌肉系统, 提出一种模型参考自适应逆补偿控制策略, 可有效克服迟滞特性以及控制过程中外界扰动和参数摄动等不确定因素对系统运动状态的影响, 实现系统高精度跟踪控制. 具体而言, 本文首先对系统的运动特性以及影响系统控制精度的不确定因素进行分析; 然后, 基于分析结果建立一个描述系统运动特性的参考模型; 进而采用逆补偿思想, 通过对所建立的参考模型求逆来构造一个逆补偿控制器, 克服迟滞特性对系统运动状态产生的影响; 随后, 基于最小均方误差算法设计自适应律, 在线辨识参考模型的权值, 同时估计逆补偿控制器的设计参数, 克服外界扰动和参数摄动等不确定因素对系统运动状态的影响; 最后, 通过实验验证所提控制策略的有效性.     

采用扰动估计的气动人工肌肉系统非线性控制

气动人工肌肉系统凭借其材质轻便、输出力大及柔顺性好等优势, 其运动控制研究近年来逐渐成为热点问题. 然而, 气动人工肌肉(pneumatic artificial muscle, PAM)系统所固有的特性(如迟滞、蠕变、非线性时变等), 为其控制方法设计与实现带来了挑战. 考虑到实际工作过程中, 系统往往遭受未知干扰的影响, 本文针对气动人工肌肉系统, 提出了一种基于干扰估计的非线性控制策略, 可在系统存在持续不确定干扰的情况下, 在线进行扰动抑制, 实现精确的跟踪控制. 具体而言, 本文先通过模型变换, 将系统不确定性、未建模动态、外部扰动等处理成集总扰动的形式. 随后, 结合自适应更新律及正则化最小二乘算法, 在线估计未知系统参数及扰动; 在精确扰动代数估计的基础上, 通过所提基于干扰估计的非线性控制器, 消除未知扰动对系统造成的影响, 并确保跟踪误差收敛至零. 此外, 经稳定性分析证明了跟踪误差的渐近收敛性. 最后, 通过硬件实验验证了本文方法的有效性及鲁棒性.     

基于DSP的传感器数据采集嵌入式系统设计

平流层飞艇传感数据测量设备用于采集平流层飞艇艇囊的内外压差、飞艇所在环境的大气压和设备供电电池的电压,并将数据处理打包后发送给飞控计算机,为飞艇的安全飞行提供关键参数,同时能够在线记录和存储数据,用于飞艇飞行后数据分析和回放。现基于TMS320F2812和分立器件,自行设计了嵌入式系统,并完成样机的研制。在设计中同时进行了冗余设计,提高数据采集和通信的可靠度。样机实验结果表明其压差数据测量精度为±5 Pa,大气压数据测量精度为±80 Pa,电池电压数据测量精度为±0. 03 V。该设计提高了传感测量的集成度和数据精度,为平流层飞艇的飞行控制提供重要依据。     

基于ARM的嵌入式网络传感器系统的设计

文章首先概述了嵌入式系统的定义和网络传感器的概念及其工作原理。在此基础上详细介绍了基于ARM处理器和CS8900网络接口芯片的嵌入式网络传感器系统的硬件设计和软件结构,以及嵌入式TCP/IP的实现。最后举例说明嵌入式网络传感器的应用前景。     

Nonlinear model-based control of pneumatic artificial muscle servo systems

This paper proposes a control methodology of the pneumatic artificial muscle (PAM) actuated servo systems. The four major processes in such systems, including the flow dynamics, pressure dynamics, force dynamics, and load dynamics, are studied to develop a full nonlinear model that encompasses all the major nonlinearities. The developed single-input-single-output model takes the valve command as the input and calculates the third-order derivative of the load position as the output. Since this model is expressed in the control canonical form, nonlinear control approaches can be easily applied. Based on this model, a sliding model controller is developed to obtain robust control in the existence of model uncertainties and disturbances. The controller is implemented on an experimental system, and the effectiveness of the proposed approach demonstrated by step response and sinusoidal tracking at different frequencies.     

Switching model predictive control of a pneumatic artificial muscle

In this article, a switching Model Predictive Controller (sMPC) scheme for the position control of a Pneumatic Artificial Muscle (PAM) is being presented. The control scheme is based on a constrained linear and PieceWise Affine (PWA) system model approximation that is able to capture the high nonlinearities of the PAM and improve the overall model accuracy, and is composed of: a) a feed-forward term regulating control input at specific reference set-points, and b) a switching Model Predictive Controller handling any deviations from the system’s equilibrium points. Extended simulation studies were utilized in order to investigate and evaluate the efficacy of the suggested controller in the positioning problem of a PAM.     

嵌入式彩色图像传感器重构系统的设计与实现

为了获取高品质的彩色图像,实现特殊作业现场的图像采集,提出了一种嵌入式彩色CCD图像传感器重构系统的设计方法.通过对图像边界方向的有效判断来完善图像高频区和低频区边界的质量,同时增加三原色之间的耦合性来提高图像清晰度,并且完成了系统的嵌入式底层实现.测试证明:该系统色彩还原效果良好,重构处理时间为34ms,稳定性好,实...     

Second generation pleated pneumatic artificial muscle and its robotic applications

This paper reports on the second generation of the pleated pneumatic artificial muscle (PPAM) which has been developed to extend the lifespan of its first prototype. This type of artificial muscle was developed to overcome dry friction and material deformation which is present in the widely used McKibben muscle. The essence of the PPAM is its pleated membrane structure which enables the muscle to work at low pressures and at large contractions. There is growing interest in this kind of actuation for robotics applications due to its high power to weight ratio and adaptable compliance, especially for legged locomotion and robot applications in direct contact with a human. This paper describes the design of the second-generation PPAM, for which specifically the membrane layout has been changed. In terms of this new layout the mathematical model, developed for the first prototype, has been reformulated. This paper gives an elaborate discussion on this mathematical model that represents the force generation and enclosed muscle volume. Static load tests on some real muscles, which have been carried out in order to validate the mathematical model, are then discussed. Furthermore, two robotic applications are given which successfully use these pneumatic artificial muscles. One is the biped Lucy and the another one is a manipulator application which works in direct contact with an operator.     

Discrete-time sliding mode control with power rate exponential reaching law of a pneumatic artificial muscle system

This paper develops a discrete-time sliding mode controller with a power rate exponential reaching law approach to enhance the performance of a pneumatic artificial muscle system in both reaching time and chattering reduction. The proposed method dynamically adapts to the variation of the switching function, which is based on an exponential term and a power rate term of the sliding surface. Thus, the controlled system can achieve high tracking performance while still obtain chattering-free control. Moreover, the effectiveness of the proposed method is validated through multiple experimental tests, focused on a dual pneumatic artificial muscle system. Finally, experimental results show the effectiveness of the proposed approach in this paper.     

嵌入式智能排泄系统的设计

介绍了一种基于AT89C52单片机嵌入式智能人工肛门的设计方案.这种智能人工肛门主要包括单片机控制模块、压力检测模块、超声检测模块和报警模块四部分.压力检测模块不断检测人工肛门肠腔内部的压力变化,并将信号传递给单片机.单片机处理来自压力检测模块的压力信号,当压力超出一定数值时,单片机启动超声检测模块.超声波发射模块发射超声波,并被肠壁另一侧的超声接收模块接收.超声波穿过肠腔内容物,将会产生一定的衰减,速度会发生变化.通过测量超声波经过肠腔内容物的时间,能够得到超声波通过肠腔内容物的平均速度,而超声波通过不同物体的速度是不同的,从而大致判断肠腔内容物的物理性质,为患者提供不同级别的警告信息.     

Development of insertion-type peristalsis pump using pneumatic artificial muscles

This study aims to develop a new type of peristaltic pump that transports high-viscosity and solid–liquid mixture fluids. Pumps capable of transporting such fluids are essential in various situations such as factory transportation, outdoors, and emergencies. These fluids are conventionally transported by positive-displacement and rotodynamic pumps. However, solid–liquid fluids could collide with the impeller of the rotodynamic pump and thereby damage the pump, whereas the positive-displacement pump must be sufficiently large to apply high pressure to the transported fluid. A small pump that can transport these fluids would save factory space and enable outdoor applications such as dredging operations. Thus, we adopted earthworm peristalsis as a model mechanism of fluid transport within a standard plumbing infrastructure. The insertion-type peristaltic pump developed in this study uses an artificial rubber muscle to achieve an earthworm-like mechanism. The capability and energy efficiency of the mechanism is evaluated in water transportation experiments.     

嵌入式公路健康监测传感器系统设计

针对公路健康监测系统监测参数多、监测范围广、实时性要求高及有线监测布线困难且易损坏等特点,设计了一种无线传输的嵌入式公路健康监测系统.该系统采用三层式结构设计,由数据采集节点、中继节点及监测中心组成;利用多传感器集成技术、单片机智能控制技术及组态王控制系统开发技术等进行软硬件构建,通过无线射频技术和数据传输装置(DTU)模块进行层间通信,最终实现对路基内部温度、湿度、压力、应变及加速度信息的实时采集与处理.初步实验结果表明:系统在4km范围内工作稳定可靠,可以满足中远距离公路监测传输需要.     

Active disturbance rejection tracking control for a nonlinear pneumatic muscle system

International Journal of Control, Automation and Systems - This paper presents active disturbance rejection tracking control for a nonlinear pneumatic muscle system. Unmodeled dynamics, varying...     

Hybrid control of a pneumatic artificial muscle (PAM) robot arm using an inverse NARX fuzzy model

We investigated the possibility of applying a hybrid feed-forward inverse nonlinear autoregressive with exogenous input (NARX) fuzzy model-PID controller to a nonlinear pneumatic artificial muscle (PAM) robot arm to improve its joint angle position output performance. The proposed hybrid inverse NARX fuzzy-PID controller is implemented to control a PAM robot arm that is subjected to nonlinear systematic features and load variations in real time. First the inverse NARX fuzzy model is modeled and identified by a modified genetic algorithm (MGA) based on input/output training data gathered experimentally from the PAM system. Second the performance of the optimized inverse NARX fuzzy model is experimentally demonstrated in a novel hybrid inverse NARX fuzzy-PID position controller of the PAM robot arm. The results of these experiments demonstrate the feasibility and benefits of the proposed control approach compared to traditional PID control strategies. Consequently, the good performance of the MGA-based inverse NARX fuzzy model in the proposed hybrid inverse NARX fuzzy-PID position control of the PAM robot arm is demonstrated. These results are also applied to model and to control other highly nonlinear systems.     

Capacitive depression sensor for microfluidic pneumatic networks

This paper reports a capacitive depression sensor intended to make measurements in-line in microfluidics pneumatic networks which works with negative pressures in the order of hundreds of millibars. The principle of operation of the sensor is neither thermal nor magnetic, but purely mechanical, and does not need a servomechanism. The proposed device is composed by two circular membranes linked by a column. This structure presents a particular behavior when exerting negative pressures between the membranes, named negative behavior. The behavior is confirmed prior to fabrication using numerical simulations. The materials used are the negative epoxy photoresist SU-8, printed circuit board (PCB) and sputtered gold. The device has been experimentally tested in the laboratory with successful results, providing an increment of capacitance from 1.7 to 3 pF for applied depressions from 0 to 500 mbar and presenting good agreement with the electromechanical FEM simulations.     

Micromachined infrared pneumatic detector for gas sensor

We present a micromachined IR detector based on the principle of a pneumatic cell and suited as an IR detector in a miniaturised gas sensor. The detector basically consists of a sealed cavity, in which the heat generated by absorbed IR light results in an increased gas pressure. This pressure rise is detected capacitively. The theoretical performance of a 1 mm² micromachined device is calculated, and it is shown that a detectivity of 3.6·10⁹ cm. Hz^1/2/W can be expected. Moreover, a pneumatic gas leak is proposed to avoid thermal drift. Using conventional Silicon micromachining techniques, a prototype was fabricated which confirmed the principle of operation., The experimental results are compared to the theory.     

Architecture for an artificial immune system

An artificial immune system (ARTIS) is described which incorporates many properties of natural immune systems, including diversity, distributed computation, error tolerance, dynamic learning and adaptation, and self-monitoring. ARTIS is a general framework for a distributed adaptive system and could, in principle, be applied to many domains. In this paper, ARTIS is applied to computer security in the form of a network intrusion detection system called LISYS. LISYS is described and shown to be effective at detecting intrusions, while maintaining low false positive rates. Finally, similarities and differences between ARTIS and Holland's classifier systems are discussed.     

嵌入DeviceNet总线接口的智能差压传感器系统

介绍了一种具有DeviceNet现场总线通信功能的智能差压传感器的设计,探讨了传感器输入输出特性曲线的非线性校正方法。通过内嵌的总线控制器(SJA1000)、报文收发器(82C251)和P89C668单片机等,该传感器可直接作为一个DeviceNet从节点工作;对传感器的输入输出特性曲线进行了建模,以软件手段实现高精度的非线性自校正功能。测试结果表明:该智能差压传感器不但具有DeviceNet现场总线输出功能,且经过多项式或神经网络建模的传感器非线性误差分别可达0.04%FS和0.02%FS。这为高精度传感器的制作提供了一种可行的方法。     

基于刮擦式传感器的嵌入式指纹识别系统设计

刮擦式指纹传感器具有体积小、功耗低的优点,适合于构建嵌入式自动指纹识别系统.介绍了一种基于Windows CE 操作系统和AES2510刮擦式指纹传感器的嵌入式自动指纹识别系统,着重阐述了基于流接口驱动模型的指纹传感器驱动程序的实现,以及基于像素灰度级变化统计信息的滑动指纹序列拼接算法.测试结果表明,系统运行效率高,占用处理器资源小.     

QFT control design for an approximately linearized pneumatic positioning system

A block‐oriented approximate feedback linearization for control of a pneumatic cylinder positioning system is introduced and a rather detailed discussion is presented on the uncertain linearization residual characterization. It is shown that making use of the characterized gain–phase information of the linearized system leads to a more reasonable trade‐off between performance and stability in the QFT control design and thus results in high control performance. Simulation and experimental results are shown. Copyright © 2003 John Wiley & Sons, Ltd.