助力机器腿仿真研究

助力机器腿是为腿部受过轻度损伤，或者因为偏瘫和脑瘫，不能稳定行走的患者设计的一种辅助行走的机器人。建立了基于广义坐标的助力机器腿逆运动学模型，采用三次样条插值规划人体的髋关节和踝关节运动轨迹，结合人体运动的几何约束和运动约束，推导出人体腿部参数化步态模型。采用图像分析方法，得到了人体行走过程中髋关节和踝关节的轨迹，通过比较分析，验证了理论分析的正确性。在Matlab／Simulink，SimMechanics下，进行了机械腿仿真分析，并给出了仿真结果。     

Underlying control strategy of human leg posture and movement

While a great number of studies on human motor control have provided a wide variety of viewpoints concerning the strategy of the central nervous system (CNS) in controlling limb movement, none were able to reveal the exact methods how the movement command from CNS is mapped onto the neuromuscular activity. As a preliminary study of human-machine interface design, the characteristics of human leg motion and its underlying motor control scheme are studied through experiments and simulations in this paper. The findings in this study suggest a simple open-loop motor control scheme in leg motion. As a possible candidate, an equilibrium point control model appears consistent in recreating the experimental data in numerical simulations. Based on the general leg motion analysis, the braking motion by the driver’s leg is modeled.     

基于康复训练中力信号的人体参与度建模

设计一种基于人机接触力的人体主动参与程度评估模型,用于康复机器人应用中的主动康复训练。通过人体的肌电信号得到肌肉活跃度,确定肌电信号与人体参与度的关系。分析这一过程中人机接触力的变化,将腿部力信号平均值以及腰部力信号方差作为模型输入,对基于肌电信号的参与度模型进行拟合,得到基于力信号的参与度模型,使用肌电信号参与度模型对力信号参与度模型进行验证,证明了该模型的有效性。该方法避免了肌电信号采集时干扰较大且准备工作繁琐等缺点,具有良好的实用性。     

Optimal locomotion trajectory for biped robot ‘D<Superscript>2</Superscript>’ with knees stretched,heel-contact landings,and toe-off liftoffs

Most of the current biped robots with active revolute joints walk with their knees bent while a human walks without bending his or her knees in “natural” gaits. This paper proposes a method to generate natural locomotion trajectory for biped robots without bending knees based on a 2-DOF model of an inverted pendulum. In addition to the natural leg motion, this paper proposes a foot trajectory that has heel-contact landing and toe-off liftoff phases similar to the human foot. The trajectory is parameterized and optimized with a genetic algorithm based on energy consumption. In simulation of locomotion of biped robot, D², which has a double deck structure of parallel mechanisms, the resulting trajectory looks natural and requires approximately 28% less energy than the one generated by the LIPM method. In addition to proposing the method to generate trajectory for a biped robot, this paper introduces the mechanism of serially linked parallel-mechanism for a biped robot with knees.     

Design of a novel side-mounted leg mechanism with high flexibility for a multi-mission quadruped earth rover BJTUBOT

Earth rover is a class of emerging wheeled-leg robots for nature exploration. At present, few methods for these robots’ leg design utilize a side-mounted spatial parallel mechanism. Thus, this paper presents a complete design process of a novel 5-degree-of-freedom (5-DOF) hybrid leg mechanism for our quadruped earth rover BJTUBOT. First, a general approach is proposed for constructing the novel leg mechanism. Subsequently, by evaluating the basic locomotion task (LT) of the rover based on screw theory, we determine the desired motion characteristic of the side-mounted leg and carry out its two feasible configurations. With regard to the synthesis method of the parallel mechanism, a family of concise hybrid leg mechanisms using the 6-DOF limbs and an L_1F1C limb (which can provide a constraint force and a couple) is designed. In verifying the motion characteristics of this kind of leg, we select a typical (3-UPRU&RRRR)&R mechanism and then analyze its kinematic model, singularities, velocity mapping, workspace, dexterity, statics, and kinetostatic performance. Furthermore, the virtual quadruped rover equipped with this innovative leg mechanism is built. Various basic and specific LTs of the rover are demonstrated by simulation, which indicates that the flexibility of the legs can help the rover achieve multitasking.     

一种仿蛙单足弹跳机器人弹跳设计与动力学分析

当前，弹跳机器人有着广泛的应用前景，提高其弹跳性能是一个值得探讨的课题。设计并分析了一种仿青蛙跳跃的弹跳腿。将其简化为双质量弹簧模型，得出了其跳起的必要条件及在空中运动状态的动力学方程。仿真结果表明，该弹跳腿的设计是可行的。     

CAE在生物力学中的应用

阐述了CAE技术在生物力学中的应用,并以人腿骨为例,采用有限元分析手段探讨了人腿骨骼固定器与治疗恢复中受伤腿骨的作用机理.     

仿生机器蟹单足惯性参数在线识别神经网络模型

机器人惯性参数识别是机器人精确建模以及机器人控制和仿真的关键问题之一。足端力传感器的接入会影响机器蟹系统的动力学特性,同时力传感器的输出也真实地反映了机器蟹的力作用和机器蟹足端的动力学特性。文中基于足端力传感器的输出信号,对在线识别仿生机器蟹单足末端惯性参数进行了分析和研究,并建立了惯性参数在线识别的神经网络模型,网络学习后其权值即为辨识的惯性参数。     

Development of a Leg Mechanism for Soft Landing Based on Biological Motion

With jumping mechanisms,soft landing motion is important to protect loads and the mechanisms.This study proposes a leg mechanism for soft landing based on biological motion.Human jumping motion with a load suggests a unique motion for soft landing.The landing model consists of two periods.Jerk is minimized in the first period and force is minimized in the second period.In comparison with other landing models,this model is specialized for soft landing motion protecting an objective part.Given all mechanisms ...     

双足仿人机器人的设计与步态分析

设计了一个双足仿人机器人,建立了机构的三维模型,对机器人腿部进行了运动学分析及步态规划,并运用ADAMS进行了仿真。结果表明结构设计及步态规划合理正确,为物理样机的制造提供了重要依据。     

基于并联机构的六分量并联天平及其力雅可比矩阵研究

为了由感测力导出被测模型受力 ,必须研究基于Stewart平台六维力传感器的力变换关系。本文将并联机构引入风洞天平 ,提出了并联天平的概念 ,应用并联机构学理论 ,对并联天平实现的关键理论问题即天平感测力与被测模型上所受的六维力的转化关系进行了研究 ,得到了二者转化的力雅可比矩阵 ,同时推导出基于 5个基本结构参数的雅可比矩阵条件数 ,并用数值算例加以验证。为该类天平的优化和设计奠定了理论基础     

Design of a robust self-excited biped walking mechanism

A self-excited biped walking mechanism consisting of two legs that are connected in a series at the hip joint through a servomotor is studied to determine range of stability. A torque proportional to angle between the shank and the vertical is seen to sustain a gait. Each leg has a thigh and a shank connected at a passive knee joint that has a knee stopper restricting the forward motion like the human knee. While a torque proportional to the angle between the shank and the vertical stabilises, the optimum proportionality constant is to be determined. A mathematical model for the dynamics of the system including the impact equations is used to analyze the stability of the system through examination of phase plane plots. For a specified proportionality constant, the range of physical parameters like leg-length and mass of leg for which the system is stable is determined. Using the stability data, a robust design has been made.     

Computer-aided design of a leg for an energy efficient walking machineLa conception assitee par ordinateur d'une jambe pour une machine marchante energetiquement efficace

Vehicles with legs instead of wheels have been studied for a number of years. One of the reasons for interest in such vehicles is that animals use only 10% as much energy as wheeled or tracked vehicles when traveling over rough terrain. The leg geometry is the most crucial aspect of the design since it strongly influences the efficiency of the vehicle. The legs should be simple in structure, and when the motion of the body is on a horizontal straight line, only one actuator per leg should be active in order to have good energy efficiency. The design of an energy efficient walking machine leg is described in this paper. In the design procedure, the motion of the leg is considered first, and a very simple leg developed from a 4-bar linkage and designed using a computer-aided interactive program is described. Second, the forces on this leg during a typical motion cycle are discussed. The leg is driven by a primary actuator for straight line walking and two secondary actuators which vary working height and change direction. A prototype of the leg is being built in The Department of Mechanical Engineering at The Ohio State University.     

Analysis on the performance of the SLIP runner with nonlinear spring leg

The spring-loaded inverted pendulum(SLIP) has been widely studied in both animals and robots.Generally,the majority of the relevant theoretical studies deal with elastic leg,the linear leg length-force relationship of which is obviously conflict with the biological observations.A planar spring-mass model with a nonlinear spring leg is presented to explore the intrinsic mechanism of legged locomotion with elastic component.The leg model is formulated via decoupling the stiffness coefficient and exponent of the leg compression in order that the unified stiffness can be scaled as convex,concave as well as linear profile.The apex return map of the SLIP runner is established to investigate dynamical behavior of the fixed point.The basin of attraction and Floquet Multiplier are introduced to evaluate the self-stability and initial state sensitivity of the SLIP model with different stiffness profiles.The numerical results show that larger stiffness exponent can increase top speed of stable running and also can enlarge the size of attraction domain of the fixed point.In addition,the parameter variation is conducted to detect the effect of parameter dependency,and demonstrates that on the fixed energy level and stiffness profile,the faster running speed with larger convergence rate of the stable fixed point under small local perturbation can be achieved via decreasing the angle of attack and increasing the stiffness coefficient.The perturbation recovery test is implemented to judge the ability of the model resisting large external disturbance.The result shows that the convex stiffness performs best in enhancing the robustness of SLIP runner negotiating irregular terrain.This research sheds light on the running performance of the SLIP runner with nonlinear leg spring from a theoretical perspective,and also guides the design and control of the bio-inspired legged robot.     

四点调平系统刚柔耦合建模及机液联合仿真

随着调平系统安全性和承载稳定性要求的提高,在提高调平精度的同时,提出了控制各支腿所受载荷不超过一定变化范围的要求。针对四点对称分布的调平系统,分析其数学模型,得出各支腿受力变化的影响因素,通过仿真结果和历史实验数据进行验证。首先利用Motion建立调平系统的三维动力学模型,然后在AMESim中建立液压控制系统模型,最后再对系统进行联合仿真并分析。结果表明,支腿受力大小与对角支腿高度和的差异以及负载偏心程度有关。采用的刚柔耦合模型的机液联合仿真方法,可为类似课题的研究提供借鉴作用。     

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.     

液压式人体行走能量回收装置设计与回收效果分析

人体行走时足底蕴藏着丰富的能量,该能量的有效回收可有效缓解穿戴电子产品、助力外骨骼等设备的能量供给问题。设计出一种将行走能量转化为液压能的能量回收机构,可供采用液压驱动的人工外骨骼循环利用。为弥补现有行走能量回收研究中往往忽略下肢行走动力学的不足,在分析步态特征的基础上,建立单腿行走过程的三自由度动力学模型。以正常成年人为对象研究单个步态周期内足底对地面作用力随时间和足部位姿的变化规律,得到行走过程中足地作用力及其水平和竖直方向分量,以及力和人行走方向夹角与足部动作的关系。依据行走能量分布规律,设计了液压式能量转化机构和存储系统用以收集行走过程中足地竖直方向作用力产生的能量,分析液压能量回收效果,结果表明无负重时单足能量回收装置的液压能输出平均功率高达20 W。     

Method for six-legged robot stepping on obstacles by indirect force estimation

Adaptive gaits for legged robots often requires force sensors installed on foot-tips, however impact, temperature or humidity can affect or even damage those sensors. Efforts have been made to realize indirect force estimation on the legged robots using leg structures based on planar mechanisms. Robot Octopus III is a six-legged robot using spatial parallel mechanism(UP-2UPS) legs. This paper proposed a novel method to realize indirect force estimation on walking robot based on a spatial parallel mechanism. The direct kinematics model and the inverse kinematics model are established. The force Jacobian matrix is derived based on the kinematics model. Thus, the indirect force estimation model is established. Then, the relation between the output torques of the three motors installed on one leg to the external force exerted on the foot tip is described. Furthermore, an adaptive tripod static gait is designed. The robot alters its leg trajectory to step on obstacles by using the proposed adaptive gait. Both the indirect force estimation model and the adaptive gait are implemented and optimized in a real time control system. An experiment is carried out to validate the indirect force estimation model. The adaptive gait is tested in another experiment. Experiment results show that the robot can successfully step on a 0.2 m-high obstacle. This paper proposes a novel method to overcome obstacles for the six-legged robot using spatial parallel mechanism legs and to avoid installing the electric force sensors in harsh environment of the robot’s foot tips.     

Operation analysis of a Chebyshev-Pantograph leg mechanism for a single DOF biped robot

In this paper, operation analysis of a Chebyshev-Pantograph leg mechanism is presented for a single degree of freedom (DOF) biped robot. The proposed leg mechanism is composed of a Chebyshev four-bar linkage and a pantograph mechanism. In contrast to general fully actuated anthropomorphic leg mechanisms, the proposed leg mechanism has peculiar features like compactness, low-cost, and easy-operation. Kinematic equations of the proposed leg mechanism are formulated for a computer oriented simulation. Simulation results show the operation performance of the proposed leg mechanism with suitable characteristics. A parametric study has been carried out to evaluate the operation performance as function of design parameters. A prototype of a single DOF biped robot equipped with two proposed leg mechanisms has been built at LARM (Laboratory of Robotics and Mechatronics). Experimental test shows practical feasible walking ability of the prototype, as well as drawbacks are discussed for the mechanical design.     

基于SolidWorks空间造型的下肢康复机设计

通过对人体步态的研究,根据机构学原理,提出了基于SolidWorks的新型下肢康复机的三维方案.这种新型康复机可以提供适合各类患者的康复方案.