Motion mechanism and gait planning of a wheeled micro robot

Based on a novel shape memory alloy （SMA） actuator, a micro worming robot is presented. The robot adopts a wheeled moving mechanism. The principle of the robot＇s enlarged pace is introduced, and the structure and motion mechanism of the SMA actuator and the wheeled moving mechanism are discussed. The gait about the robot＇s rectilinear movement and turning movement is also planned. Under the effect of the eccentric wheel self-locking mechanisms and changing-direction mechanisms, the robot can move forward and backward, and turn actively, which overcomes the disadvantages of the traditional SMA micro robots to a certain extent. Furthermore, some experiments on the heating current of the SMA actuator and the robot＇s motion capability are carded out.

A gait planning method applied to hexapod biomimetic robot locomotion

In order to fulfill the goal of autonomous walking on rough terrain,a distributed gait planningmethod applied to hexapod biomimetic robot locomotion is proposed based on the research effort of gait co-ordination mechanism of stick insect.The mathematical relation of walking velocity and gait pattern wasdepicted,a set of local rules operating between adjacent legs were put forward,and a distributed networkof local rules for gait control was constructed.With the interaction of adjacent legs,adaptive adjustmentof phase sequence fluctuation of walking legs resulting from change of terrain conditions or variety of walk-ing speed was implemented to generate statically stable gait.In the simulation experiments,adaptive ad-justment of inter-leg phase sequence and smooth transition of velocity and gait pattern were realized,andstatic stableness was ensured simultaneously,which provided the hexapod robot with the capability ofwalking on rough terrain stably and expeditiously.

Novel algorithm of gait planning of hydraulic quadruped robot to avoid foot slidingand reduce impingement

In order to solve kinematic redundancy problems of a hydraulic quadruped walking robot,which include leg dragging,sliding,impingement against the ground,an improved gait planning algorithm for this robot is proposed in this paper.First,the foot trajectory is designated as the improved composite cycloid foot trajectory.Second,the landing angle of each leg of the robot is controlled to satisfy friction cone to improve the stability performance of the robot.Then with the controllable landing angle of quadruped robot and a geometry method,the kinematic equation is derived in this paper.Finally,agait planning method of quadruped robot is proposed,a dynamic co-simulation is done with ADAMS and MATLAB,and practical experiments are conducted.The validity of the proposed algorithm is confirmed through the co-simulation and experimentation.The results show that the robot can avoid sliding,reduce impingement,and trot stably in trot gait.

Gait planning and intelligent control for a quadruped robot

We present a method for designing free gaits for a structurally symmetrical quadruped robot capable of performing statically stable, omnidirectional walking on irregular terrain. The robot＇s virtual model is constructed and a control algorithm is proposed by applying virtual components at some strategic locations. The deliberative-based controller can generate flexible sequences of leg transferences while maintaining walking speed, and choose optimum foothold for moving leg based on integration data of exteroceptive terrain profile. Simulation results are presented to show the gait＇s efficiency and system＇s stability in adapting to an uncertain terrain.

Study on Gait Planning of Dynamic Walking of Biped Robots Based on Optimization Theory

In this paper, two important problems in the gait planning of dynamic walking of biped robot, i.e., finding inverse kinematic solution and constructing joint trajectories, are studied in detail by adopting complex optimization theory. The optimization algorithm for finding the inverse kinematic solution is developed, the construction method of joint trajectories is given, and the gait planning method of dynamic walking of biped robots is proposed.

A Humanoid Robot Gait Planning and Its Stability Validation

Gait planning based on linear inverted pendulum (LIPM) on structured road surface can be quickly generated because of the simple model and definite physical meaning. However, over-simplifi- cation of the model and discontents of zero velocity and acceleration boundary conditions when robot starts and stops walking lead to obvious difference between the model and the real robot. In this paper, parameterized gait is planned and trajectories’ smoothness of each joint angle and centroid are ensured using the 3-D LIPM theory. Static walking method is used to satisfy zero velocity and acceleration boundary conditions. Besides, a multi-link model is built to validate the stability. Simulation experiments show that: despite of some deviation from the theoretical solution, the actual zero-moment point (ZMP) is still within the support polygon, and the robot walks steadily. In consequence, the rationality and validity of model simplification of LIPM is demonstrated.

Design,Mobility Analysis and Gait Planning of a Leech-like Soft Crawling Robot with Stretching and Bending Deformation

Soft climbing/crawling robots have been attracting increasing attention in the soft robotics community,and many prototypes with basic locomotion have been implemented.Most existing soft robots achieve locomotion by planar bending deformation and lack sufficient mobility.Enhancing the mobility of soft climbing/crawling robots is still an open and challenging issue.To this end,we present a novel pneumatic leech-like soft robot,Leechbot,with both bending and stretching deformation for locomotion.With a morphological structure,the robot consists of a three-chambered actuator in the middle for the main motion,two chamber-net actuators that act as ankles,and two suckers at the ends for anchoring on surfaces.The peristaltic motion for locomotion is implemented by body stretching,and direction changing is achieved by body bending.Due to the novel design and two deformation modes,the robot can make turns and transit between different surfaces;the robot,hence,has excellent mobility.The development of the robot prototype is presented in detail in this paper.To control its motion,tests were carried out to determine the relationship between step length and air pressure as well as the relationship between motion speed and periodic delay time.A kinematic model was established,and the kinematic mobility and surface transitionability were analyzed.Gait planning based on the inflating sequence of the actuating chambers is presented for straight crawling,turn making,and transiting between surfaces and was verified by a series of experiments with the prototype.The results show that a high mobility in soft climbing/crawling robots can be achieved by a novel design and by proper gait planning.

Minimum-Time and Minimum-Jerk Gait Planning in Joint Space for Assistive Lower Limb Exoskeleton

Assistive lower limb exoskeleton robot has been developed to help paraplegic patients walk again.A gait planning method of this robot must be able to plan a gait based on gait parameters,which can be changed during the stride according to human intention or walking conditions.The gait is usually planned in cartesian space,which has shortcomings such as singularities that may occur in inverse kinematics equations,and the angular velocity of the joints cannot be entered into the calculations.Therefore,it is vital to have a gait planning method in the joint space.In this paper,a minimum-time and minimum-jerk planner is proposed for the robot joints.To do so,a third-order system is defined,and the cost function is introduced to minimize the jerk of the joints throughout the stride.The minimum time required is calculated to keep the angular velocity trajectory within the range specified by the motor’s maximum speed.Boundary conditions of the joints are determined to secure backward balance and fulfill gait parameters.Finally,the proposed gait planning method is tested by its implementation on the Exoped®exoskeleton.

Energy-efficient Bio-inspired Gait Planning and Control for Biped Robot Based on Human Locomotion Analysis

In this paper an experiment of human locomotion was carried out using a motion capture system to extract the human gait features. The modifiable key gait parameters affecting the dominant performance of biped robot walking were obtained from the extracted human gait features. Based on the modifiable key gait parameters and the Allowable Zero Moment Point （ZMP） Variation Region （AZR）, we proposed an effective Bio-inspired Gait Planning （BGP） and control scheme for biped robot to- wards a given travel distance D. First, we construct an on-line Bio-inspired Gait Synthesis algorithm （BGSN） to generate a complete walking gait motion using the modifiable key gait parameters. Second, a Bio-inspired Gait Parameters Optimization algorithm （BGPO） is established to minimize the energy consumption of all actuators and guarantee biped robot walking with certain walking stability margin. Third, the necessary controllers for biped robot were introduced in briefly. Simulation and experiment results demonstrated the effectiveness of the proposed method, and the gait control system was implemented on DRC-XT humanoid robot.

Design of bionic goat quadruped robot mechanism and walking gait planning

In order to improve the walking stability and obstacle jumping ability of the robot on the slope,the goat was taken as the bionic prototype,a kind of bionic goat quadruped robot has been designed.By the bionic principle,the mechanical structure of the quadruped robot was designed,and the Denavit-Hartenberg(D-H)method was used to build the kinematic model,through which the forward and inverse kinematics of the robot was calculated,thus the equations of velocity and acceleration of the joint angle change were obtained during the quadruped robot motion,providing control theory foundation for robots.During walk gait planning,a low contact compact foot trajectory planning method using a high order polynomial curve was used to carry out the foot trajectory planning of the robot for the swing phase and stance phase.Through MATLAB software simulation,the simulation results of MATLAB software showed that the trajectory of the foot of the quadruped robot was semi-elliptic in a gait cycle,which were basically consistent with the foot trajectory obtained from the previous goat slope walking test.Therefore,the simulation results by MATLAB software showed that the foot trajectory was reasonable.Based on this,a gait plan was carried out,and the sequence of the lift leg steps of the robot was obtained.The test platform for the whole machine was built.The results showed that the height of the leg of the quadruped robot was 7.37 cm,and the length of the gait was 28.40 cm.Compared with the planned average gait length S=30 cm and average step height H=7 cm,the error of the leg height and the gait length was 5.28%and 5.33%,respectively.The designed gait planning achieved the expected results.The knee joint angle varied from 126.3°to 156.1°,and the hip joint angle varied from 103.9°to 138.4°.The changes in the joint angle of the quadruped robot could prove the correctness of the foot motion trajectory planning,which will provide a theoretical basis for the structural design and gait planning of the quadruped robot.

A Smooth and Efficient Gait Planning for Humanoids Based on Human ZMP

Based on the ZMP(zero moment point)trajectory and the walking data of human,a new method is proposed to improve the robot walking smoothness as well as to save energy.Firstly,a measurement system is designed to measure the data of humans including the ZMP trajectory and the waist trajectory.Secondly,a new gait planning method which includes presetting the allowable ZMP region is proposed through analyzing human data.Thirdly,the new planning method is applied to the multi-link model based gait planning method.Finally,the feasibility of the proposed method is verified by simulation and experiments.

Research on Biologically Inspired Hexapod Robot's Gait and Path Planning

Realistically there are many robot joints in the biologically inspired hexapod robot, so they will generate many complexities in the calculations of the gait and the path planning and the control variables. The software Solidworks and MSC. ADAMS are adopted to simulate and analyze the prototype model of the robot. By the simulations used in our design, the applicability of the tripod gait is validated, and the scheme which uses cubic spline curve as the endpoint of foot＇s path is feasible. The principles, methods, and processes of the simulation of hexapod robot are illustrated. A methodology is proposed to get the robot inverse solution in ADAMS, and to simplify the theoretical calculation, and further more to improve the efficiency of the design.

Undulatory gait planning method of multi-legged robot with passive-spine

In this paper,we propose a new gait planning method for a multi-legged robot which has only 1 degree-of-freedom in each leg and has a passive body joint between two body segments.We firstly introduce the Finite State Machine(FSM)to the undulatory gait planning method of the 2n-legged robot.Then,the undulatory gait sequence for straight line motion is achieved by undulations motion.The idea that legged locomotion is achievable by less actuation of 2n-legged robot as well as the gait planning methods are verified finally by simulations and experiments.

Inverted Modelling:An Effective Way to Support Motion Planning of Legged Mobile Robots

This paper presents an effective way to support motion planning of legged mobile robots—Inverted Modelling,based on the equivalent metamorphic mechanism concept.The difference from the previous research is that we herein invert the equivalent parallel mechanism.Assuming the leg mechanisms are hybrid links,the body of robot being considered as fixed platform,and ground as moving platform.The motion performance is transformed and measured in the body frame.Terrain and joint limits are used as input parameters to the model,resulting in the representation which is independent of terrains and particular poses in Inverted Modelling.Hence,it can universally be applied to any kind of legged robots as global motion performance framework.Several performance measurements using Inverted Modelling are presented and used in motion performance evaluation.According to the requirements of actual work like motion continuity and stability,motion planning of legged robot can be achieved using different measurements on different terrains.Two cases studies present the simulations of quadruped and hexapod robots walking on rugged roads.The results verify the correctness and effectiveness of the proposed method.

面向桁架攀爬的三分支机器人步态规划方法

为解决载荷大范围在轨平稳搬运问题,设计三分支机器人面向桁架攀爬的步态规划方法,使其能够平稳搬运载荷运动到部署位置完成大型航天器组装任务。以21自由度三分支机器人为研究对象,结合桁架结构划分多种攀爬步态单元;针对每种步态单元规划了单元周期内2条攀爬分支的交替夹持顺序以及末端的夹持位姿;针对大范围桁架搬运任务,基于可夹持区域构建表征桁架表面任意两杆间可过渡性的邻接矩阵,并利用Floyd算法生成距离矩阵与路径矩阵,规划出任意两杆间的最短攀爬路径,并将路径中的桁架杆件节点序列映射为机器人可执行的步态单元序列;基于三次B样条曲线对每种步态单元周期内2条攀爬分支的末端轨迹进行规划,实现攀爬分支末端在两夹持点间的攀爬过渡。仿真实验表明:所设计的步态规划方法能够使机器人实现在不同位置关系的桁架杆件之间的过渡,从而具备到达桁架表面任意位置的能力。

Research on Gait Trajectory Planning of Wall-Climbing Robot Based on Improved PSO Algorithm

In order to reduce the labor intensity of high-altitude workers and realize the cleaning and maintenance of high-rise building exteriors,this paper proposes a design for a 4-DOF bipedal wall-climbing bionic robot inspired by the inchworm’s movement.The robot utilizes vacuum adsorption for vertical wall attachment and legged movement for locomotion.To enhance the robot’s movement efficiency and reduce wear on the adsorption device,a gait mimicking an inchworm’s movement is planned,and foot trajectory planning is performed using a quintic polynomial function.Under velocity constraints,foot trajectory optimization is achieved using an improved Particle Swarm Optimization(PSO)algorithm,determining the quintic polynomial function with the best fitness through simulation.Finally,through comparative experiments,the climbing time of the robot closely matches the simulation results,validating the trajectory planning method’s accuracy.

受海龟爬行与山羊行走启发的四足仿生移动机器人多步态规划及动力学分析

为解决救援机器人运动速度慢、环境适应性差和步态单一等问题,参照海龟与山羊的生理结构,设计了一种四足仿生移动机器人。首先,根据海龟能在松软地面上爬行以及山羊运动能力强的特点,为机器人规划了仿海龟爬行和仿山羊行走两种步态以适应不同环境,提高了机器人的运动性能。然后,对机器人支腿进行了动力学分析,通过建立动力学模型来获取机器人关节扭矩与运动性能参数之间的定量关系。最后,通过仿真和样机实验来验证机器人步态的可行性以及机器人的环境适应能力。结果表明,所设计的机器人结构稳定,步态规划合理,可适应不同的复杂地形。研究结果可为仿生机器人的设计与开发提供重要参考。

月基装备行走运动学分析与连续步态规划

针对缓冲行走功能一体的月面探测器构型设计困难、步态分析复杂等问题,提出了一种基于相同支链构型的四足月基装备(LBE)设计分析方法与连续步态规划方案。设计复合功能着陆腿机构及整机多状态位姿;构建LBE在行走状态下的单腿运动学模型,对其进行正逆运动学求解,分析单腿与整机工作空间和运动性能;对LBE整机进行水平月面的连续步态规划,并设计单步足端轨迹,通过动力学仿真,验证LBE行走步态稳定性。仿真结果表明:LBE沿前进方向连续稳定运行,质心竖直方向浮动仅占整器高度的0.24%,俯仰角最大摆动幅度为0.34°,翻滚角最大摆动幅度为0.27°。

金属矿山井下采场六足机器人运动分析及步态规划

六足机器人因其结构特殊带来的良好越障能力成为仿生机器人研究的热点,然而,金属矿山井下采场矿石堆积、崎岖不平的特点,给这类机器人的行走稳定性、越障性带来更多的挑战。因此,为使六足机器人在井下具有更好的通过性,对其运动能力和步态规划进行了相关研究。首先仿照自然界六足生物,设计六足机器人结构,对其腿部进行运动学分析;然后规划了用于采场的直行步态,结合采场路面环境设计了一种直线—摆线复合轨迹提升越障性,同时分析了机器人爬坡稳定性,对爬坡步态进行了优选;最后对规划步态进行仿真和现场模拟试验。仿真和试验结果表明,所规划的足端轨迹能跨越抬腿高度85%的障碍物,并且对矿石堆积形成的采场路面有更好的避障能力;三角步态爬坡时在坡底和坡顶过渡阶段容易打滑,而横向步态可以实现平滑的过渡,爬坡性能更佳。

十二杆张拉整体结构动态分析及路径规划研究

张拉整体因其区别于传统结构的特点在土木和可动结构领域有广泛的发展前景,目前学者对于多步态或更复杂的球形张拉整体研究较少,且一些传统路径规划方法不适用于多面体张拉整体结构.因此,本文采用几何方法找寻了一种多步态的十二杆球形张拉整体结构(Snub-12)的合理构型,并用找形方法进行了验证.定义并分析了Snub-12的多种基本步态和各步态形成的理论路径空间,并将其与单步态的6杆球形张拉整体结构(TR-6)进行对比,明确了两种结构运动的特点和区别.对快速搜索随机树算法进行改进并利用其产生引导路径,结合Snub-12步态组合的情况,生成适合不同场景的合理运动路径,最后通过仿真分析验证了方法的可行性和有效性.分析结果表明:同等条件下,不论是路径空间中盲区占比还是独立滚动步态的翻滚步长,Snub-12均优于TR-6,更适宜开展长距离运动.基于引导策略的路径规划方法可以解决多步态张拉整体结构的路径规划问题,这丰富了球形张拉整体结构的运动理论,可以为该类球形张拉整体可动结构的实际应用提供了理论支撑.