自适应模糊算法优化的足球机器人轨迹跟踪

为了提高足球机器人在运动控制过程中的轨迹跟踪性能和稳定性,将自适应模糊PID算法用于机器人运动控制环节中,对PID参数进行实时调整。建立足球机器人在场地上的控制系统模型,分析机器人在轨迹跟踪中由驱动方向、角度等时变因素导致的实际轨迹发生偏移的问题,分别在MATLAB-Simulink和SimRobot仿真平台对优化算法的性能进行仿真,同时与传统的PID控制进行对比。实验结果表明,自适应模糊PID算法相比传统的PID控制器在最大跟踪误差和平均跟踪误差方面分别减少20.18%和29.34%,同时提升了系统的稳定性。该控制算法提升了足球机器人的轨迹跟踪性能,满足机器人在运动过程中的动力学和控制要求,易于在工程中应用。     

基于模型预测控制的排爆机器人轨迹跟踪算法研究EI北大核心CSCD

排爆机器人在复杂、危险环境下代替人作业拥有非常重要的地位。排爆机器人对期望轨迹的跟踪是避免发生危险最重要的环节。基于模型预测控制算法提出了排爆机器人末端轨迹跟踪算法。给出了机械臂状态空间的离散模型,已知当前时刻位置状态和下一时刻位置输入状态,预测未来某时域内的输出状态;然后根据给定性能指标和约束条件,求解未来一段时域内的输入序列,对实际输出进行反馈校正;最后,采用实验仿真对比测试,验证了该算法的有效实时性,结果表明,基于模型预测控制的机器人末端轨迹跟踪算法具有良好的动态实时跟踪能力,实现了目标轨迹的有效跟踪。     

并联机器人轨迹跟踪离散变结构鲁棒控制器设计

本文根据并联机器人支撑杆教学模型参数摄动较大和时变的特点,设计了一种用于并联机器人轨迹跟踪的离散滑模变结构鲁棒控制器,通过引入变速趋近律,控制系统响应速度快,对参数摄动和外界干扰具有较强的鲁棒性,仿真研究结果表明,本文的控制方案能实现较高精度的快速轨迹跟踪,同时可削弱或避免通常变结构控制中不可避免的抖振。     

机器人负载惯性参数的快速辨识

机器人的惯性参数辨识是基于动力学模型控制器设计的基础,除了需要辨识机器人自身的惯性参数外,还需要快速准确地辨识负载的惯性参数。针对需要更换负载的工作场景,提出了一种快速辨识负载的激励轨迹,该轨迹不需要经过优化,即可在短时间内覆盖更多的机器人运动状态,从而获得更为全面的采样参数集,提高了辨识效率的同时增强了辨识模型的泛化能力。实验表明,辨识的结果与负载模型的CAD参数符合,机器人关节理论力矩能较好地拟合实际驱动力矩,验证了负载参数的正确性。     

机器人操作手轨迹跟踪的一种仿人智能控制

机械手的轨迹跟踪是机器人控制系统中的一个难点,文中将仿人智能控制应用于自行设计的机器人操作手上,实验证明,方法行之有效。     

遥控挖掘机器人轨迹跟踪的电液比例控制系统

为实现自动挖掘，在挖掘机器人的轨迹规划器给出铲斗期望的运动轨迹的情况下，需要挖掘机的控制系统能够控制其工作装置实现对给定轨迹的准确跟踪。电液比例阀兼有开关控制和伺服控制的优点。能实现对液压系统流量和方向的比例控制。该文提出了一种对常规挖掘机的液压回路进行简单的改造后，在挖掘机上既能实现常规手柄操作控制，又能实现电液比例遥控轨迹跟踪的液压回路。在建立系统数学模型的基础上，该文提出了一种PID参数自适应的控制策略，并利用仿真实验对其性能进行验证。     

柔性机器人轨迹跟踪的逆动力学分析

基于绝对坐标,以期望轨迹而不是名义刚性位置作为机器人末端点的边界条件,建立了具有柔性关节和柔性杆的机器人的逆动力学模型,此方法可使柔性机器人非常准确地跟踪期望轨迹。最后,提出了求解此类非线性方程的数值算法。通过对３Ｒ机器人进行仿真,表明本方法优于通常的方法。     

考虑关节柔性误差的机器人参数辨识方法研究

考虑到工业机器人绝对定位精度较低,无法满足高精度加工的需要,故提出了一种综合型误差补偿方法。以改进的D-H模型为基础,建立机器人末端工具中心点的距离误差模型,同时对主要受力关节2和3由于自重或者外加负载产生的柔性变形误差进行了研究,建立了柔性误差模型,最后以激光跟踪仪作为测量设备,利用最小二乘法对模型进行求解,通过修正控制器参数补偿误差提高机器人定位精度。经过补偿,自主研发的机器人定位精度有明显的提高,从之前的3.548 mm降至0.939 mm。     

基于参数自适应神经动力力学的轮式机器人轨迹跟踪控制

轮式机器人具有复杂多变的非线性、强耦合以及时变的动力学特点,采用传统的机器人轨迹跟踪控制容易产生较大的速度突变,导致机器人在控制过程中产生抖振现象,为此提出了一种基于参数自适应神经动力力学的轮式机器人轨迹跟踪控制方法。通过运动学分析并建立轮式机器人的位姿误差模型,采用神经动力学设计机器人轨迹跟踪控制器;分析比较不同参数取值与控制量之间的关系,设计了一种参数自适应方法进一步提高轨迹跟踪控制器的性能;最后,通过对所设计的控制方法进行了仿真实验。实验结果表明,所设计的控制方法能够保证机器人拥有较小的速度突变,在出现误差情况下能够以较快速度收敛,在轨迹跟踪上拥有较高的精度。     

离合器从动盘测试机控制系统建模及其参数估计

提出了一种离合器从动盘测试机位置控制系统模型参数估计方法.通过分析系统各个环节建立了系统简化数学模型;采用最小二乘法对模型参数进行估计.经仿真实验验证,辨识参数模型能较好的反映了系统开环特性;应用复合形法求解该优化问题,提高了求解速度.     

Adaptive output-feedback control with prescribed performance for trajectory tracking of underactuated surface vessels

In this paper, we address the problem of trajectory tracking control of underactuated surface vessels in a quantitative method with only position and attitude available. Combined with high-gain observer, parameter compression algorithm and performance function, an adaptive control scheme with prescribed performance is proposed. The high-gain observer is constructed to estimate the velocities, and the parameter compression algorithm is adopted to address persistent perturbations and model uncertainties in a more concise way. By prescribed performance function, the controller can be designed with prescribed performance. The results about system stability is given and proved by using the Lyapunov direct method. The signals concerning with all the errors converge to a bounded set. Compared with the existing methods, the developed scheme can reduce the number of tuning parameters, and guarantee the tracking errors bounded within the prescribed performance constraints in the transformed coordinate, which means the steady errors, convergence rates and maximum overshoots can be guaranteed by the performance function. Comparison and numerical simulations are given to demonstrate the effectiveness of the proposed scheme.     

Measuring the velocity of fluorescently labelled red blood cells with a keyhole tracking algorithm

In this paper we propose a tracking algorithm to measure the velocity of fluorescently labelled red blood cells travelling through microvessels of tumours, growing in dorsal skin flap window chambers, implanted on mice. Preprocessing removed noise and artefacts from the images and then segmented cells from background. The tracking algorithm is based on a ‘keyhole’ model that describes the probable movement of a segmented cell between contiguous frames of a video sequence. When a history of cell movement exists, past, present and a predicted landing position of the cells will define two regions of probability that resemble the shape of a keyhole. This keyhole model was used to determine if cells in contiguous frames should be linked to form tracks and also as a postprocessing tool to join split tracks and discard links that could have been formed due to noise or uncertainty. When there was no history, a circular region around the centroid of the parent cell was used as a region of probability. Outliers were removed based on the distribution of the average velocities of the tracks. Since the position and time of each cell is recorded, a wealth of statistical measures can be obtained from the tracks. The algorithm was tested on two sets of experiments. First, the vasculatures of eight tumours with different geometries were analyzed; average velocities ranged from 86 to 372 μm s^?1, with minimum and maximum track velocities 7 and 1212 μm s^?1, respectively. Second, a longitudinal study of velocities was performed after administering a vascular disrupting agent to two tumours and the time behaviour was analyzed over 24 h. In one of the tumours there is a complete shutdown of the vasculature whereas in the other there is a clear decrease of velocity at 30 min, with subsequent recovery by 6 h. The tracking algorithm enabled the simultaneous measurement of red blood cell velocity in multiple vessels within an intravital video sequence, enabling analysis of heterogeneity of flow and response to treatment in mouse models of cancer.     

Performance analysis of two-degree of freedom fractional order PID controllers for robotic manipulator with payload

The robotic manipulators are multi-input multi-output (MIMO), coupled and highly nonlinear systems. The presence of external disturbances and time-varying parameters adversely affects the performance of these systems. Therefore, the controller designed for these systems should effectively deal with such complexities, and it is an intriguing task for control engineers. This paper presents two-degree of freedom fractional order proportional-integral-derivative (2-DOF FOPID) controller scheme for a two-link planar rigid robotic manipulator with payload for trajectory tracking task. The tuning of all controller parameters is done using cuckoo search algorithm (CSA). The performance of proposed 2-DOF FOPID controllers is compared with those of their integer order designs, i.e., 2-DOF PID controllers, and with the traditional PID controllers. In order to show effectiveness of proposed scheme, the robustness testing is carried out for model uncertainties, payload variations with time, external disturbance and random noise. Numerical simulation results indicate that the 2-DOF FOPID controllers are superior to their integer order counterparts and the traditional PID controllers.     

A fast iterative recursive least squares algorithm for Wiener model identification of highly nonlinear systems

In this paper, an online identification algorithm is presented for nonlinear systems in the presence of output colored noise. The proposed method is based on extended recursive least squares (ERLS) algorithm, where the identified system is in polynomial Wiener form. To this end, an unknown intermediate signal is estimated by using an inner iterative algorithm. The iterative recursive algorithm adaptively modifies the vector of parameters of the presented Wiener model when the system parameters vary. In addition, to increase the robustness of the proposed method against variations, a robust RLS algorithm is applied to the model. Simulation results are provided to show the effectiveness of the proposed approach. Results confirm that the proposed method has fast convergence rate with robust characteristics, which increases the efficiency of the proposed model and identification approach. For instance, the FIT criterion will be achieved 92% in CSTR process where about 400 data is used.     

3自由度气动串联机械手的关节控制

3自由度气动机械手属关节串联式机器人,机械手在运动过程中,转动惯量、重力矩及关节间的耦合力矩等参数都会发生较大变化,影响了机械手末端的运动精度。针对这些问题,利用拉格朗日方程对机械手3关节进行动力学分析,得到多关节联动时单关节力矩方程。以腰部关节为例,通过对关节动力机构的数学模型线性化处理,采用状态反馈极点配置方法进行控制器设计,试验表明具有一定鲁棒性,但存在一定静态误差。分析产生误差的原因主要是干扰力矩的影响,根据单关节规划路径通过动力学模型得到补偿力矩,利用输入前馈对关节实施动态补偿。试验验证了方法的有效性,从结果可以看出,该组合控制策略抑制了扰动,提高了轨迹跟踪精度。     

A recursive algorithm for generating the equations of motion of spatial mechanical systems with application to the five-point suspension

In this paper, a recursive formulation for generating the equations of motion of spatial mechanical systems is presented. The rigid bodies are replaced by a dynamically equivalent constrained system of particles which avoids introducing any rotational coordinates. For the open-chain system, the equations of motion are generated recursively along the serial chains using the concepts of linear and angular momenta. Closed-chain systems are transformed to open-chain systems by cutting suitable kinematic joints and introducing cut-joint constraints. The formulation is used to carry out the dynamic analysis of multi-link five-point suspension. The results of the simulation demonstrate the generality and simplicity of the proposed dynamic formulation.     

CVT轻度混合动力系统电动机和发动机联合工作模式下的系统效率优化

进行无级变速器(Continuously variable transmission, CVT)轻度混合动力电动汽车关键部件效率的试验数值建模,基于效率数值模型和系统的纵向动力学方程,分析推导出混合动力电动汽车驱动工况不同工作模式下的系统效率计算公式,得到了系统效率优化模型,利用序列二次规划算法对CVT轻度混合动力电动汽车驱动工况的系统效率进行优化计算,从而确定了驱动工况不同工作模式下的最佳电动机/发电机输出功率和最佳CVT速比,为驱动工况下CVT轻度混合动力汽车系统效率的提高和控制策略的优化提供了方法和依据。