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This paper investigates the high precision way-point tracking control problems for dynamic unicycles. Firstly, a simplified electrical motor is used to provide the torques in unicycle’s dynamic model. Then, in order to improve the tracking precision, a kinematic controller and a dynamic controller are proposed to drive the unicycle to its given way-points, respectively. A group of parameter conditions is developed for the tracking system to avoid the singularity. Comparing with the other tracking methods, our proposed tracking controllers can effectively drive the dynamic unicycle to its targets with high precision. The stability and performance of proposed tracking method are strictly analyzed in both kinematic and dynamic levels. In final, numerical simulations are provided to verify the effectiveness and advantages of proposed approaches. 相似文献
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在三轴曲面加工中,曲面加工质量与刀位轨迹的质量有紧密联系。在使用当前的计算机辅助设计(CAD)/计算机辅助制造(CAM)集成软件生成刀位轨迹时,若仅采用通常的0.01mm公差,在加工时有可能出现表面凹坑、光洁度较差等缺点。为解决上述问题,提出一种基于网格均匀化的刀位轨迹优化方法,在Cimatron生成的加工刀位轨迹基础上,通过建立主导轮廓线并对不规则的点进行修正来降低相邻刀路倾斜度变化的程度;然后对同一条刀路上的刀位点进行光滑连续直线段的识别;再采用分段3次样条进行拟合,以提高同一刀路上的曲线光滑程度。仿真实验与实际加工实验表明,本方法可以消除原来存在的表面凹坑,有效地提高最终的表面加工质量。 相似文献
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《Journal of The Franklin Institute》2022,359(16):8713-8741
In this paper, the optimal driving torques of four wheels in an electric vehicle (EV) are obtained by minimizing the losses of four in-wheel motors. In order to slightly change these optimal torques for vehicle stability recovery, a new constrained active front steering (AFS) system is analytically designed and integrated with the torque vectoring (TV) system in a novel decentralized structure. In the proposed structure, the required external yaw moment is applied by the TV controller only when the constrained AFS is filled to capacity determined by a stability index extracted from the nonlinear phase plane analysis. As a result of this integration strategy, the external yaw moment is used as low as possible. Consequently, the torques in electrical motors are used near the optimal values consistent with optimal energy consumption. Comparative simulation studies with the standalone TV are conducted in the CarSim software environment to show the efficiency of the proposed decentralized control structure in terms of energy consumption and stability. Moreover, the suitability of the constrained control method used in the integration structure is shown in comparison with the well-known nonlinear model predictive control method in terms of practical implementation. 相似文献
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《Journal of The Franklin Institute》2019,356(14):7611-7625
In this paper we investigate an inerter equipped with a prototype continuously variable transmission (CVT) designed for the novel tuned mass damper. Inerter enables stepless changes of inertance via varying transmission ratio of the CVT. The main difference from classical inerter is addition of CVT, hence we present its design and properties in details. Motion of the proposed CVT is oscillatory and we test it for the actual working conditions. We derive the mathematical model of the system that include dissipation via dry friction. We analyse the actual transmission ratio, internal motion resistances and identify the inertia of CVT components using energy conservation method and validate further. Finally, we apply actual working conditions and compare the experimental and numerical exciting torques of the CVT. We obtain good agreement between them, hence the proposed model is robust and gives reliable results. 相似文献
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In this paper an adaptive second order terminal sliding mode (SOTSM) controller is proposed for controlling robotic manipulators. Instead of the normal control input, its time derivative is used in the proposed controller. The discontinuous sign function is contained in the derivative control and the actual control obtained after integration is continuous and hence chatterless. An adaptive tuning method is utilized to deal with the system uncertainties whose upper bounds are not required to be known in advance. The performance of the proposed control strategy is evaluated through the control of a two-link rigid robotic manipulator. Simulation results demonstrate the effectiveness of the proposed control method. 相似文献
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《Journal of The Franklin Institute》2022,359(4):1427-1456
The energy regulation of fully actuated torque–driven robot manipulators in joint space is addressed in this paper. The proposed controller is designed via an energy shaping plus damping injection approach. The contribution is the proposal of an energy regulator with partial damping injection capable of inducing oscillations in the undamped joints of robot manipulators, with an user specified desired frequency and amplitude, by adding only damping in the rest of the joints, which may require less control effort than a trajectory tracking controller with full damping injection. Although viscous friction is considered in all joints of robot manipulator, it has been compensated via the proposed energy regulator. Moreover, the controlled periodic motion oscillates around a desired joint position as reference, and this provides a nice feature in the robot, mainly when there is not interest in the undamped joint to follow an specified time-varying sinusoidal function, but generating an oscillatory motion of constant amplitude and frequency. Instrumental in stability analysis is the Lyapunov’s theory and LaSalle’s theorem, which allows concluding that the closed-loop trajectories approach an invariant set that could include a unique equilibrium or periodic orbits. Numerical simulations on a manipulator arm model of two degrees of freedom illustrate the main results. 相似文献
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《Journal of The Franklin Institute》2023,360(6):4399-4426
Unmanned surface vehicles (USVs) are a promising marine robotic platform for numerous potential applications in ocean space due to their small size, low cost, and high autonomy. Modelling and control of USVs is a challenging task due to their intrinsic nonlinearities, strong couplings, high uncertainty, under-actuation, and multiple constraints. Well designed motion controllers may not be effective when exposed in the complex and dynamic sea environment. The paper presents a fully data-driven learning-based motion control method for an USV based on model-based deep reinforcement learning. Specifically, we first train a data-driven prediction model based on a deep network for the USV by using recorded input and output data. Based on the learned prediction model, model predictive motion controllers are presented for achieving trajectory tracking and path following tasks. It is shown that after learning with random data collected from the USV, the proposed data-driven motion controller is able to follow trajectories or parameterized paths accurately with excellent sample efficiency. Simulation results are given to illustrate the proposed deep reinforcement learning scheme for fully data-driven motion control without any a priori model information of the USV. 相似文献
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《Journal of The Franklin Institute》2023,360(11):7105-7127
Space robots play a more and more important role in on-orbit service missions. It is essential for a space robot to stabilize its attitude rapidly after capturing an unknown target, because of its residual momentum. Regarding uncertainties in inertial parameters of the target, process and measurement, and insufficient measurements, this paper first presents extended Kalman filter (EKF) enhanced model predictive control (MPC) strategy for rapid attitude stabilization of space robots with bounded control torque of the actuator and the manipulator in postcapture, in which motion of the manipulator is planned to make up for the limitation of the actuator. Thanks to the Jacobian matrix, which is required for EKF, the linear varying time-MPC is applied to handle the constraints of the drive torque, which can be solved by the online active set method effectively and efficiently. Simulation has been done for the 2D and the 3D models, and the results show that the whole system, including the base and the manipulator can be stabilized, and inertial parameters of the target can converge to their ideal values with the constraints. In addition, robustness of the presented method has been verified by Monte Carlo simulation. 相似文献
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为弥补缺乏从行业附加值视角研究碳排放强度和部门生产环节碳排放结构的不足,以更好地分析碳排放变动情况,基于消费者视角,同时考虑附加值对碳排放的影响,将引起碳排放的因素分解为能源结构效应、能源强度效应、附加值效应、投入结构效应和最终需求效应并构建研究模型,以广东为例,利用其2007年、2012年和2017年投入产出表数据,采用结构分解分析（SDA）法和结构路径分析（SPA）法对广东及其部分行业碳排放情况进行分析。结果表明：对于广东而言,能源强度效应是碳排放减少的主要因素,最终需求效应是碳排放增加的主要因素;直接碳强度和完全碳强度增加的部门主要是能源部门,其碳排放呈现增加状态,其中直接消耗引起的碳排放比例增加,间接消耗引起的碳排放集中在第1和第2层生产环节上;能源强度效应是非能源部门直接碳排放和完全碳强度降低的关键因素。最后,从应对最终需求高碳化对碳排放的影响、能源消费结构和产业结构优化调整以及政府调控手段等方面对促进广东碳减排提出有关对策建议。 相似文献
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《Journal of The Franklin Institute》2019,356(13):7112-7143
This paper addresses the problem of robust integrated fault estimation (FE) and fault-tolerant control (FTC) for a class of discrete-time networked Takagi–Sugeno (T–S) fuzzy systems with two-channel event-triggered schemes, input quantization and incomplete measurements. The incomplete information under consideration includes randomly occurring sensor saturation and randomly occurring quantization. In order to save the limited networked resources, this paper firstly proposed a novel dynamic event-triggered scheme on the sensor side and a static one on the controller side. Secondly, an event-triggered FE observer for the T–S fuzzy model is designed to estimate actuator faults and system states, simultaneously. Then, a specified discrete sliding surface in the state-estimation space is constructed. By using time-delay analysis technique and considering the effects of event-triggered scheme, quantization, networked conditions, actuator fault and external disturbance, the sliding mode dynamics and error dynamics are unified into a new networked time-delay model. Based on this model, sufficient conditions are established such that the resulting augmented fuzzy system is stochastically stable with a prescribed H∞ performance level with a single-step linear matrix inequality (LMI) formulation. Furthermore, an observer-based sliding mode controller for reaching motion is synthesized to guarantee the reachability of the sliding surface. Finally, a single-link flexible manipulator example is present to illustrate the effectiveness of the proposed method. 相似文献
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文章以摇杆滑块机构滑块沿任意曲线做匀速运动为目标,首先建立相应的矢量方程式并进行求解,接着又用Pro/E软件建立简单骨架模型进行仿真分析,研究方法及获得结果为进一步研究机构铰链处驱动电机的控制方法提供了一定的依据。 相似文献
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《Journal of The Franklin Institute》2018,355(18):9127-9149
This paper proposes a dual terminal sliding mode control scheme for tracking tasks of rigid robotic manipulators. As a significant novelty, the presented design technique integrates the individual sliding mode surfaces to achieve the finite time convergence of tracking errors utilizing specially designed construct, and accordingly the convergence time is easily obtained due to the integral design. The underactuated issue and input limitation are specially considered in this paper, i.e., the underactuated issue is solved by introducing the hierarchical methodology into the basic dual sliding mode controller. The proposed method can easily combine with the adaptive technique to eliminate the negative effect caused by the input limitation in the rigorous stability analysis. These newly proposed methods also have the characteristics of nonsingularity and chattering suppression, and the effectiveness and high efficiency are verified by stabilizing the motions of the overhead crane and the tracking tasks of the rigid robotic manipulator. Simulation results validate the theoretical analyses about the proposed method. 相似文献
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《Journal of The Franklin Institute》2021,358(16):8356-8376
In this paper, the tracking control problem of uncertain Euler–Lagrange systems under control input saturation is studied. To handle system uncertainties, a leakage-type (LT) adaptive law is introduced to update the control gains to approach the disturbance variations without knowing the uncertainty upper bound a priori. In addition, an auxiliary dynamics is designed to deal with the saturation nonlinearity by introducing the auxiliary variables in the controller design. Lyapunov analysis verifies that based on the proposed method, the tracking error will be asymptotically bounded by a neighborhood around the origin. To demonstrate the proposed method, simulations are finally carried out on a two-link robot manipulator. Simulation results show that in the presence of actuator saturation, the proposed method induces less chattering signal in the control input compared to conventional sliding mode controllers. 相似文献
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《Journal of The Franklin Institute》2022,359(15):7913-7935
In this study, an autonomous capture framework was proposed for a tumbling target satellite with a space manipulator. First, the motion model of a tumbling target was constructed and the motion properties were analyzed. Subsequently, a predictive motion control method was introduced to compensate for the time delay owing to image processing and to predict the tumbling motion of the target. Stability analysis was conducted using a Lyapunov function. To address the problem of large position and attitude deviations of the tumbling target, different autonomous capture strategies, that is, non-fixed-point position-based capture and area-based capture, were proposed to capture different parts of the target, such as the docking ring and side surfaces, which are important for practical applications. The capture conditions were created and compared, where the non-fixed-point position capture strategy and area-based capture strategy had a larger pose tolerance than the traditional fixed-point position methods. Finally, the framework was tested using Adams/Simulink co-simulations. The results validated the autonomous capture process and proposed alternatives for practical applications. 相似文献
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Eber Jafet Ávila-Martínez Juan Gonzalo Barajas-Ramírez 《Journal of The Franklin Institute》2021,358(4):2346-2366
This paper addresses the flocking motion problem for swarms of agents with two restrictions: limited communication/detection ranges and different input constraints. In this problem, the distance between pairs of agents determines if a communication/detection link exists among them, while each agent has a different control action bound. We use the notion of proximity graph to model communication/detection between agents and provide distributed controllers designed for leaderless and leader-followers flocking motion scenarios. Our proposed designs preserve the connectivity of the proximity graph while the control effort satisfies the bound of each particular agent. Unlike previous results, our protocols take advantage of the group’s input heterogeneity to use agents with a greater capacity to compensate for neighbors that are less capable of meeting the group’s requirements. Additionally, our designs are based only on local state errors and are robust to non-modeled edge failures. To illustrate the effectiveness of our proposal, we use numerical simulations of different flocking scenarios. 相似文献
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构建包含OFDI因素的制造业集聚决定模型,运用2003~2013年间中国30个省市的面板数据进行参数估计,对中国制造业集聚的影响路径进行了详细分析.研究发现,OFDI的规模经济效应和逆向技术溢出效应对中国制造业产值区位熵和Krugman专业化系数有着显著正向影响.分区位看,东部地区OFDI能带来资本存量和研发投入增加,制造业集聚效应更为明显;分行业看,OFDI能通过增强资本禀赋以及自主创新禀赋对我国技术密集型制造业集聚程度的促进作用较为明显.最后,提出相应对策. 相似文献
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中国产业部门的能耗强度特征及节能减排的分类实现路径 总被引：6，自引：2，他引：4
产品生产过程中除了直接消耗能源之外,还有通过中间产品投入而产生的间接能源消耗。因此,仅仅依靠提高能源利用效率来进行节能减排,其作用是有限的,必须要综合考虑生产过程中对能源、物质投入的需求。本文通过投入产出方法分析了我国2002年各个产品部门单位产值的直接和间接能源消耗,发现大部分产品部门单位产值的间接能耗都大于直接能耗,即生产过程中的大量物质投入导致了大量的间接能源消耗。因此,要实现节能减排的目标,直接能耗高的部门要提高其能源利用效率,而间接能耗高的部门要提高其中间投入的利用效率,同时要推动低能耗的服务业的发展以及在全社会推进“减物质化”发展,减少物质消耗而导致的间接能源消耗,而这需要人力资本的大量积累以及服务业的发展。 相似文献
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This paper presents an adaptive robust control strategy based on a radial basis function neural network (RBFNN) and an online iterative correction method (OICM) for a planar n-link underactuated manipulator with a passive first joint to realize its position control objective. An uncertain model of the planar n-link underactuated manipulator is built, which contains the parameter perturbation and the external disturbance. The adaptive robust controllers based on the RBFNN are designed to realize the model reduction, which makes the system reduce to a planar virtual three-link underactuated manipulator (PVTUM) and simplifies the complexity of the system control. An online differential evolution (DE) algorithm is used to calculate the target angles of the PVTUM based on the nominal model parameters. The control of the PVTUM is divided into two stages, and the adaptive robust controllers are still employed to realize the control objective of each stage. Then, the OICM is used to correct the deviations of all link angles of the PVTUM caused by the parameter perturbation, which makes the end-point of the system gradually approach to its target position. Finally, simulation results of a planar four-link underactuated manipulator demonstrate the effectiveness of the proposed adaptive robust control strategy. 相似文献