共查询到19条相似文献,搜索用时 406 毫秒
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刘文倩单梁王志强吴志强戚志东李军 《控制工程》2023,(11):2100-2107
针对机械臂逆解求取过程中存在大量矩阵变换、计算成本高的问题,采用位姿分离法对逆运动学求解过程进行改进,并提出基于自适应步长的RRT-connect路径规划算法。首先建立六自由度机械臂连杆坐标系模型,采用Standard Denavit-Hartenberg(D-H)方法对机械臂进行正运动学分析,得到机械臂末端执行器位姿相对于基座的齐次变换矩阵。然后引入位姿分离法改进了机械臂的逆运动学求解方法,将机械臂运动学逆解分为位置逆解和姿态逆解两部分,分别用几何法和解析法进行求解,减少了整体计算量。再者提出基于自适应步长的改进RRT-connect路径规划算法,解决了扩展速度慢的问题。最后通过仿真验证所提出方法的正确性和有效性。 相似文献
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三分支机器人协调操作及关节力矩优化 总被引:3,自引:0,他引:3
针对三分支机器人协调运动,采用分离影响系数法分离各个分支的雅可比矩阵和惯性矩阵,再重新组合成整个系统的雅可比矩阵和惯性矩阵,建立三分支机器人运动学和动力学方程.应用乘子罚函数方法,对三分支机器人基于最小关节驱动力矩优化设计,避免矩阵的奇异值分解,提高计算的稳定性,应用迭代方法,简化了问题的求解. 相似文献
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为了提高6自由度并联机构运动学正解的求解效率,增强求解方法的通用性,提出了一种6-UPS(universal-prismatic-spherical)机构的运动学正解算法.首先在6-UPS机构任意分支虎克铰处添加2个角度传感器,测量了虎克铰2个方位的旋转角度.再基于旋转矩阵构建12个方程,通过代数消元对其进行降次处理得到简易的一元二次方程组.最后,求得6-UPS机构的运动学正解.并通过具体数值算例验证所提方法,求出了确定的位置正解.该方法不仅降低了数据处理的难度,且能求得正解的唯一解,避免了并联机构正解存在多解的问题. 相似文献
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本文以七自由度双臂带电作业机器人为研究对象,针对七自由度逆运动学求解计算复杂,实时控制困难的问题,在分析机器人的机械结构及建立正向运动学模型的基础上,采用位姿分解法与代数迭代法相结合的方式求解运动学逆解,将七自由度逆运动学求解转化为四自由度位置冗余问题,并设计了具体的程序流程图,经过仿真验证,该算法减小了逆运动学求解的计算量,提高了机器人控制的实时性。 相似文献
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We study the problem of converting a trajectory tracking controller to a path tracking controller for a nonlinear non-minimum phase longitudinal aircraft model. The solution of the trajectory tracking problem is based on the requirement that the aircraft follows a given time parameterized trajectory in inertial frame. In this paper we introduce an alternative nonlinear control design approach called path tracking control. The path tracking approach is based on designing a nonlinear state feedback controller that maintains a desired speed along a desired path with closed loop stability. This design approach is different from the trajectory tracking approach where aircraft speed and position are regulated along the desired path. The path tracking controller regulates the position errors transverse to the desired path but it does not regulate the position error along the desired path. First, a trajectory tracking controller, consisting of feedforward and static state feedback, is designed to guarantee uniform asymptotic trajectory tracking. The feedforward is determined by solving a stable noncausal inversion problem. Constant feedback gains are determined based on LQR with singular perturbation approach. A path tracking controller is then obtained from the trajectory tracking controller by introducing a suitable state projection. 相似文献
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This letter gives an efficient algorithm for tracking the solution curve of sparse logistic regression with respect to the regularization parameter. The algorithm is based on approximating the logistic regression loss by a piecewise quadratic function, using Rosset and Zhu's path tracking algorithm on the approximate problem, and then applying a correction to get to the true path. Application of the algorithm to text classification and sparse kernel logistic regression shows that the algorithm is efficient. 相似文献
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Ryo Watada Makoto Ohsaki Yoshihiro Kanno 《Structural and Multidisciplinary Optimization》2011,43(4):459-471
Uniqueness and symmetry of solution are investigated for topology optimization of a symmetric continuum structure subjected
to symmetrically distributed loads. The structure is discretized into finite elements, and the compliance is minimized under
constraint on the structural volume. The design variables are the densities of materials of elements, and intermediate densities
are penalized to prevent convergence to a gray solution. A path of solution satisfying conditions for local optimality is
traced using the continuation method with respect to the penalization parameter. It is shown that the rate form of the solution
path can be formulated from the optimality conditions, and the uniqueness and bifurcation of the path are related to eigenvalues
and eigenvectors of the Jacobian of the governing equations. This way, local uniqueness and symmetry breaking process of the
solution are rigorously investigated through the bifurcation of a solution path. 相似文献
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对传统的导弹制导系统进行改进设计,改善导弹的路径跟踪效果。首先引入Dubins曲线对导弹进行航迹规划进行,并基于滑模控制进行导弹制导策略的设计,自动驾驶仪系统采用级联比例积分控制器。Dubins曲线能为导弹创建更平滑的参考轨迹,减少导弹的超冲运动与振荡现象。滑模控制通过计算导弹与参考轨迹的相对距离,获得参考方位角,进而实现对参考轨迹的跟踪,能够提高制导系统响应速度、抗干扰能力。对导弹跟踪路径效果进行仿真,对比引入dubins曲线前后导弹的跟踪轨迹的误差与振荡现象,证明了引入dubins曲线对于导弹的路径规划工作具有显著帮助,并对结果中的一些现象进行了讨论。并已dubins曲线作为仿真路径,对传统比例制导策略和改进型滑模控制制导策略的仿真结果进行对比,证明了改进型制导系统设计的可行性,并对其路径跟踪表现的特点进行了讨论。 相似文献
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针对传统几何轨迹跟踪算法切向角获取依赖高精度惯导设备的问题,提出了基于三次B样条曲线拟合的轨迹跟踪算法。首先,通过对先验地图中的离散轨迹点进行拟合生成平滑轨迹线;然后,根据轨迹方程通过插值法重新生成离散路点,并计算各个路点处的切向角,从而实现了对多传感器融合轨迹的优化与跟踪。在真实的智能车实验平台上,用所提算法对20km/h低速绕圈和60km/h较高速度直道两种典型场景进行了在真实道路下的跟踪测试。在低速大曲率和较高速度直道两种典型场景下,所提算法轨迹跟踪的最大横向误差均保持在0.3m以内。实验结果表明,该算法有效解决了传统几何轨迹跟踪算法对惯导设备依赖的问题,同时保持了较好的跟踪性能。 相似文献
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Roland Lenain Mathieu Deremetz Jean-Baptiste Braconnier Benoit Thuilot Vincent Rousseau 《Advanced Robotics》2017,31(9):453-467
This paper proposes a control strategy to achieve high accurate path tracking in off-road conditions. The approach is based on adaptive and predictive techniques to account for sliding effects and actuator properties. An extended kinematic model is designed using sideslip angles definition. An observer is proposed to estimate online these variables, independently from the reference path and robot velocity. Thanks to the proposed approach, high accurate path tracking can then be achieved whatever the shape of the reference path and the task to be achieved (practical stabilization or moving object tracking). 相似文献
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In order to avoid wheel slippage or mechanical damage during the mobile robot navigation, it is necessary tosmoothly change driving velocity or direction of the mobile robot. This means that dynamic constraints of the mobile robotshould be considered in the design of path tracking algorithm. In the study, a path tracking problem is formulated asfollowing a virtual target vehicle which is assumed to move exactly along the path with specified velocity. The drivingvelocity control law is designed basing on bang-bang control considering the acceleration bounds of driving wheels. Thesteering control law is designed by combining the bang-bang control with an intermediate path called the landing curve whichguides the robot to smoothly land on the virtual target's tangential line. The curvature and convergence analyses providesufficient stability conditions for the proposed path tracking controller. A series of path tracking simulations and experimentsconducted for a two-wheel driven mobile robot show the validity of the proposed algorithm. 相似文献
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Ehsan Hashemi Maani Ghaffari Jadidi Navid Ghaffari JadidiAuthor vitae 《Robotics and Autonomous Systems》2011,59(11):930-942
The purpose of this study is to suggest and examine a PI–fuzzy path planner and associated low-level control system for a linear discrete dynamic model of omni-directional mobile robots to obtain optimal inputs for drivers. Velocity and acceleration filtering is also implemented in the path planner to satisfy planning prerequisites and prevent slippage. Regulated drivers’ rotational velocities and torques greatly affect the ability of these robots to perform trajectory planner tasks. These regulated values are examined in this research by setting up an optimal controller. Introducing optimal controllers such as linear quadratic tracking for multi-input–multi-output control systems in acceleration and deceleration is one of the essential subjects for motion control of omni-directional mobile robots. The main topics presented and discussed in this article are improvements in the presented discrete-time linear quadratic tracking approach such as the low-level controller and combined PI–fuzzy path planner with appropriate speed monitoring algorithm such as the high-level one in conditions both with and without external disturbance. The low-level tracking controller presented in this article provides an optimal solution to minimize the differences between the reference trajectory and the system output. The efficiency of this approach is also compared with that of previous PID controllers which employ kinematic modeling. Utilizing the new approach in trajectory-planning controller design results in more precise and appropriate outputs for the motion of four-wheeled omni-directional mobile robots, and the modeling and experimental results confirm this issue. 相似文献