轮腿式复合机器人设计及运动实现

通过机械结构和控制系统设计,研制了轮式和腿式独立运动的轮腿式复合机器人。应用PWM对机器人的关节控制进行了研究。分析了其腿式运动、轮式运动和轮腿变形的过程,并进行了实验验证。结果表明,研制的机器人具有结构简单、易于控制的特点,解决了现有轮腿式机器人运动时与地面摩擦力不够的问题,具有很好的应用前景。     

一种新型轮腿配合式管道机器人设计

本文提出一种新型轮腿配合式管道机器人的设计思想。这种机器人通过轮式驱动和腿式驱动二者的相互配合,兼有轮式机器人移动速度快及腿式机器人环境适应能力强等优点。文章对整体方案进行设计,针对腿式驱动系统,做了步态协调与机器人行进分析,设计的凸轮机构及重心偏移系统,实现了机器人腿式行进时的平稳行走,设计有一定创新性。     

Learning gait of quadruped robot without prior knowledge of the environment

Walking is the basic skill of a legged robot, and one of the promising ways to improve the walking performance and its adaptation to environment changes is to let the robot learn its walking by itself. Currently, most of the walking learning methods are based on robot vision system or some external sensing equipment to estimate the walking performance of certain walking parameters, and therefore are usually only applicable under laboratory condition, where environment can be pre-defined. Inspired by the rhythmic swing movement during walking of legged animals and the behavior of their adjusting their walking gait on different walking surfaces, a concept of walking rhythmic pattern(WRP) is proposed to evaluate the walking specialty of legged robot, which is just based on the walking dynamics of the robot. Based on the onboard acceleration sensor data, a method to calculate WRP using power spectrum in frequency domain and diverse smooth filters is also presented. Since the evaluation of WRP is only based on the walking dynamics data of the robot’s body, the proposed method doesn’t require prior knowledge of environment and thus can be applied in unknown environment. A gait learning approach of legged robots based on WRP and evolution algorithm(EA) is introduced. By using the proposed approach, a quadruped robot can learn its locomotion by its onboard sensing in an unknown environment, where the robot has no prior knowledge about this place. The experimental result proves proportional relationship exits between WRP match score and walking performance of legged robot, which can be used to evaluate the walking performance in walking optimization under unknown environment.     

五足步行机攀登不等距桁架运动分析

对五足步行机攀登桁架运动进行了详细的分析,提出了一种实用攀登步态;在此基础上,针对不等间距杵架,建立了其攀登运动模型及相应的算法。该方法不仅可直接应用于五足步行机在不等间距桁架上的攀登运动规划,而且还可作为五足步行机攀登杵架的运动条件,对于步行在具有不连续落足区的非结构地形下的运动研究也具有普遍指标意义。     

一种足式移动机器人的混合视觉伺服控制方法

针对一种配有单目相机的足式移动机器人,提出一种基于图像单应性的混合视觉伺服方法,利用单应性矩阵中的元素构造状态变量估计估计机器人相对位姿,使机器人在缺乏深度信息的情况下可准确到达目标位姿。相较于轮式移动机器人,在足式机器人移动过程中,足式机构的间歇性运动直接影响机器人视觉反馈过程和伺服控制系统的准确性和稳定性。为解决这一问题,通过分析足式机构运动学并建立足式机器人移动速度与电机转速的映射关系,使控制器可以更准确地调整机器人运动速度。考虑到足式机构运动对视觉反馈环节的影响,提出一种改进型自适应中值滤波算法提高位姿估计精度。伺服环节设计了滑模控制器,并采用李雅普诺夫方法证明了控制系统的稳定性。最后,利用CoppeliaSim软件搭建足式移动机器人虚拟模型,通过仿真验证了所提出控制方案的可行性与有效性。     

轮腿式爬楼梯移动机器人的设计及运动特性分析

针对非结构化复杂环境对移动机器人的运动要求,结合轮式和腿式移动机构的优点,设计了一种高效、稳定的轮腿式爬楼梯移动机器人。设计了机器人的主要结构,分析了机器人的稳定性及转向性能。平地行走、转向、越障、上下楼梯等实验结果表明:设计的轮腿式爬楼梯移动机器人结构简单,运动灵活,控制方便,控制精度高,不需对运行步态进行预先规划,它不仅可以在崎岖不平的环境中实现快速行驶,而且实现了快速稳定的爬楼梯功能,具有很强的越障能力和环境适应能力。     

液压驱动单元基于力的阻抗控制系统前馈抗扰控制研究

液压驱动单元(Hydraulic drive unit,HDU)是液压驱动型足式机器人常用的关节驱动器,具有集成度高、功率密度大等特性。机器人顶层规划后,需依靠其完成具体动作,实现机器人的行走、对角小跑、奔跑等步态。HDU所受外负载会随机器人腾空相和着地相频繁大幅变化,严重影响系统性能。若HDU具备高性能基于力的阻抗控制,则可有效减小机器人在运动过程中足地接触时的碰撞力,保证机器人运动的平稳性。为提高基于力的阻抗控制系统的抗外扰动能力,研究一种前馈抗扰控制(Feedforward disturbance rejection control,FDRC)。介绍HDU基于力的阻抗控制系统及其数学模型,推导其非线性状态空间表达式。针对系统的外扰动推导等价输入矩阵,设计前馈抗扰控制器,并估算伺服阀流量系数。利用HDU性能测试试验台,针对不同工况和典型信号进行试验。试验结果表明,FDRC可大幅提高HDU基于力的阻抗控制系统的抗外扰动能力,且工况适应性良好。该控制方法可降低外扰动对液压驱动型机器人的影响,提高机器人的适应性。     

Footholds optimization for legged robots walking on complex terrain

This paper proposes a novel continuous footholds optimization method for legged robots to expand their walking ability on complex terrains. The algorithm can efficiently run onboard and online by using terrain perception information to protect the robot against slipping or tripping on the edge of obstacles, and to improve its stability and safety when walking on complex terrain. By relying on the depth camera installed on the robot and obtaining the terrain heightmap, the algorithm converts the discrete grid heightmap into a continuous costmap. Then, it constructs an optimization function combined with the robot’s state information to select the next footholds and generate the motion trajectory to control the robot’s locomotion. Compared with most existing footholds selection algorithms that rely on discrete enumeration search, as far as we know, the proposed algorithm is the first to use a continuous optimization method. We successfully implemented the algorithm on a hexapod robot, and verified its feasibility in a walking experiment on a complex terrain.     

双半转腿式机器人运动稳定性分析

提出一种新型的双半转腿式机器人,主要由车体支架、两条轮腿及其轮腿支架组成.根据双半转腿式机器人的步行运动特点,将机器人的一个完整步行周期分为4腿支撑阶段和双腿支撑阶段.针对双腿支撑阶段的稳定性问题,提出3点假设,将机器人的跨步过程简化成一个支点不变、摆长不断变化的倒立摆模型.以机器人平地行走为例,分别建立机器人各杆件的质心坐标方程,并推导出机器人的质心运动方程.根据机器人倒立摆模型,分析影响其运动稳定性的因素.以此为基础,利用MATLAB软件对机器人平地行走时的质心姿态、质心速度以及后跨步杆端部位姿进行仿真,仿真结果表明,双半转腿式机器人的平地运动是稳定的.     

QW-Ⅰ型全方位四足步行机器人的设计及实验研究

本文介绍了QW-Ⅰ型四足步行机的设计特点及其层次式控制系统结构,着重研究了以规则步态实现全方位行走问题,提出通过侧行步态的切换及触地腿的局部调整来实现沿给定路线运动的方案。完成了样机研制,进行了实验研究。     

六足步行机的稳定性监控系统

本文综合了各种地形条件下的六足步行机的静态稳定性方法,详细讨论了能量稳定法,并用这种方法分析了六足步行机的越野能力,研究了六足机转向时的步态选择及其稳定性,给出了六足机总体结构尺寸的一种CAD方法,设计了一个适于各种地形条件的六足步行机的稳定性监控系统。     

大型17R“加藤一郎”机器人仿人行走控制研究

针对大型17R"加藤一郎"结构双足机器人仿人行走控制问题,从仿人机器人的机械结构、控制系统、步态仿真、动力学参数等方面对机器人的影响进行了研究,采用仿生学原理,参考了人体上、下半身比例特点,对机器人的机械结构进行了设计;对机器人控制系统进行了设计,提出了一种基于DSP+FPGA的主控系统,将多CPU协同工作、分布式远程控制技术应用到仿人机器人行走控制中;利用人类行走过程中各关节的转动参数为输入的控制方法,在ADAMS上进行了步态行走试验,分析了动力学参数对机器人步态的影响。研究结果表明,以人类行走方式控制机器人步态行走,机器人行走步态稳定可行,可应用于大型双足步行机器人步态行走控制。     

Biped walking robot based on a 2-UPU+2-UU parallel mechanism

Existing biped robots mainly fall into two categories： robots with left and right feet and robots with upper and lower feet. The load carrying capability of a biped robot is quite limited since the two feet of a walking robot supports the robot alternatively during walking. To improve the load carrying capability, a novel biped walking robot is proposed based on a 2-UPU＋2-UU parallel mechanism. The biped walking robot is composed of two identical platforms（feet） and four limbs, including two UPU（universal-prismatic-universal serial chain） limbs and two UU limbs. To enhance its terrain adaptability like articulated vehicles, the two feet of the biped walking robot are designed as two vehicles in detail. The conditions that the geometric parameters of the feet must satisfy are discussed. The degrees-of-freedom of the mechanism is analyzed by using screw theory. Gait analysis, kinematic analysis and stability analysis of the mechanism are carried out to verify the structural design parameters. The simulation results validate the feasibility of walking on rugged terrain. Experiments with a physical prototype show that the novel biped walking robot can walk stably on smooth terrain. Due to its unique feet design and high stiffness, the biped walking robot may adapt to rugged terrain and is suitable for load-carrying.     

步行康复机器人轨迹控制方法研究

为了满足神经受损患者步行康复训练需要,设计了以外骨骼助行腿为核心的步行康复机器人,其重要的要求是保证机器人的运动轨迹符合患者康复训练要求。为使机器人能模拟步态为患者提供康复训练,在合理的步态规划后对轨迹的控制方法进行了研究,在控制系统软、硬件平台上完成了步行康复机器人助行腿的两种轨迹控制方式(位置控制和速度控制)。通过实验验证了控制方式的可行性,满足了患者步态训练需要。同时实验结果表明,速度控制方式比位置控制方式更加适合步行康复机器人。     

考虑足地作用的足式机器人环境表征与路径规划

足式机器人在行走过程中,足端与地面之间的相互作用影响机器人的地面通过情况。足地作用与地表的几何形状和地面的物理特性息息相关,因此仅基于几何特性地图进行路径规划难以满足野外环境下规避松软沙土等非几何危险的需求。针对该问题,考虑足地作用力学提出包含几何与物理特性的环境模型进行足式机器人路径规划。通过简化和统一软硬地面下的足地作用模型,提出表征地面法向松软特性和切向摩擦特性的参数化指标,结合几何特性构建更全面的环境模型。综合考虑影响机器人通过性的地面几何与物理特征,重构路径规划的优化目标,通过图搜索算法实现最优路径规划。以六足机器人Elspider为对象进行仿真和试验,验证了所提出的方法能够有效规避非几何危险,实现了更安全、通过性更强的路径规划。     

基于模糊ＰＩ的管道清淤机器人控制系统研究

为了精确控制一款新型管道清淤机器人的运动状态，保证该机器人能在管道的恶劣环境中稳定工作，设计了整机的运动控制系统并对轮式行走单元的驱动系统进行模糊 ＰＩ算法研究；然后在３组行走单元的控制系统之间设计了速度补偿器，使它们具有耦合关系，以保证３组行走单元的同步性。利用Ｓｉｍｕｌｉｎｋ对以上控制方法进行了模拟仿真和实验。实验结果表明，基于模糊 ＰＩ算法的控制系统可实现对机器人运行状态的精确控制，令该系统具有良好的可控性和抗干扰性；通过速度补偿器建立３组行走单元之间的耦合关系，实现了它们的同步协调运转，并增强了该机器人的运动平稳性，能够满足清淤机器人的设计要求。     

轮腿式机器人步态生成的拓扑矩阵方法

为实现机器人在核电救灾等非结构化环境中的步态规划和自适应行走,以六足轮腿式机器人为研究对象提出基于当前地形的机器人自适应在线生成步态的规划策略,通过全局地形环境中机器人对前进方向局部地形的实时识别,确定其基本地形类型,产生相应的基本步态,动态生成机器人的步态序列。定义机器人触地状态及其列矢量表达,给出机器人步态因子的分类及其拓扑矩阵;定义基本地形及相应的基本步态,给出基本步态的拓扑矩阵;在此基础上,提出基于地形识别的步态拓扑规划策略和步态拓扑矩阵生成流程,通过矩阵递推算法实现机器人步态拓扑的动态生成。     

Energetic walking gaits studied by a simple actuated inverted pendulum model

The mechanical structure and the joint torques configuration are the important parts in the biped robot design. Meanwhile, different walking speed and step length should be chosen to achieve efficient gait according to different need of walking environment. Therefore, this paper investigates the energetic walking gaits using a simple actuated inverted pendulum model. Joint torques and push-off impulse are both added in the model. The walking gaits with different joint torques configuration and with different combination of walking speeds and step lengths are analyzed. The results show that hip velocity direction is changed by the push-off impulse just before the heelstrike, which reduces the energy consumption of each step. The walking gait with minimal energy consumption is the walking pattern only with push-off, the energy cost of which is 1/4 of the walking pattern only with joint torque during the swing phase. The cost of transport (COT) and the push-off impulse of the walking gait is increasing with the increase of walking speed and step length. Using same value of push-off impulse, the walking with long step length and slow speed is more efficient. The paper can provide suggestions for designing advanced legged robot systems with high energy efficiency and various gaits. For example, the consideration of push-off mechanism can be used in the biped robots design.

     

Computer-aided geometric design of legs for a walking vehicle

A legged vehicle is potentially more energy efficient and mobile than conventional vehicles in rough terrain. The performance of such a legged vehicle is strongly dependent on the leg geometry. In general, a leg linkage which possesses three-degree-of-freedom foot motion is adequate. A preliminary design of the leg with a view to good energy efficiency resulted in a four-bar leg. This was described by S. M. Song et al. [Mech. Mach. Theory 19, 17–24 (1984)]. In the present paper, the mobility of the legged vehicle is brought into consideration in the leg design. A study of the mobility of a six-legged vehicle shows that a large walking envelope is required for each leg linkage. In order to satisfy this requirement, the original four-bar leg was modified into a seven-bar leg by mounting another four-bar linkage on the coupler of the original four-bar linkage. Also, a different type of leg linkage based on pantograph mechanism was designed. A comparison of the leg performance of both types of leg is made in this paper and the pantograph leg is found to be more effective.     

四足爬行机器人步态分析与运动控制

为了实现液压作动的四足步行机器人的稳定行走,根据运动稳定裕量原则规划四足机器人的直行步态,保证三足支撑机体时稳定裕量为100 mm;针对液压缸运动加速度突变导致机体冲击振动的问题,提出了利用S型曲线作为各自由度的运动位移控制规律的方法。按照JQRI00型四足步行机器人原理样机的结构建立了虚拟样机模型,应用仿真软件对所设计步态进行了仿真,分析了步态的运动学、动力学特征和位移控制方法的运动特征;在四足步行机器人原理样机上进行了试验,并将试验与仿真结果进行了比较。研究结果表明,所设计的机器人步态可行,保证了机器人具有较好的行走稳定性;将S型曲线用于位移控制,消除了液压缸运动加速度的突变,进一步提高了机体运行的平稳性。