Papers by Keyword: Biped Robot

Abstract: Unlike human beings, a robot will fall without a sufficient walking foot-ground clearance, which is essential to a success walking. However, to obtain less calculating time and simpler analysis, foot scuffing is ignored in most studies during numerical simulations of passive dynamic walkers which can walk down a gentle slope and are actuated only by their own gravity. So this paper initials a study on the effects of a passive dynamic walker’s mechanical parameters on foot-ground clearance and the results can be used to make a further parameters optimization based on walking stability analysis. A passive dynamic walking model with a hip joint, knee joints, ankle joints and an upper body and a prototype were built and numerical simulations were implemented to analyze the effects of mechanical parameters on foot-ground clearance. Finally, the results were validated in prototype experiments.

Abstract: The foot robot has a good adaptability to terrain and hydraulic drive has a great power to weight ratio compared with other drivers, therefore, a hydraulically actuated biped robot is proposed to meet the need for the high flexibility and high load capability, and each leg has four degrees of freedom. According to the proportion of human leg, the leg mechanism of biped robot is designed .A kind of simplified structure of the hydraulic biped robot is put forward based on the analysis of the structure. The model of the leg is established by Lagrange equation to obtain the corresponding dynamic model; the model of the hydraulic system is established according to the hydraulic control theory; the whole model of the leg is obtained combined with the two models. The variable structure control is suitable for the complex high-order control system, keeps invariant for external disturbance and parameter changes, and easily implements the control algorithm on-line, so the variable structure control is used to study on the motion control of the robot. The simulation is executed in Matlab software, which verifies that the mechanical structure is reasonable and the control algorithm is effective.

Abstract: Programming a biped robot to walk is a challenging issue in robotics. For a stable gait, prior knowledge of the robot’s physical parameters and sophisticated control algorithms are required. Robot walking by imitating a human gait becomes new challenging issues. Using a human motion data to the robot’s walk is convenient even though direct usage of the data usually results in dynamically unstable motion. The purpose of this paper is to develop a new type of encoder and foot sensor for biped imitation control system, which is direct and real-time sensor system. Characteristics of the sensor system are discussed. Finally, the operator’s joint motion can be imitated to the robot by using the new type of wearable encoder sensor. CoP through the developed foot sensor can be obtained and utilized to walk.

Abstract: The study of biped robot has long history and continuation. One of important moving processes is walking procedure. The walking posture is an important research field that always adapts and implements in the biped robot. The walking research field is very interesting because the walking posture of humans is flexible and stable. Additionally, the force that affect on the humans foot is also investigated. This research addresses the walking simulation of small biped robots that have tiptoe and bigtoe. The study based on the assumption that the bigtoe size affects on the walking posture and walking distance. The gait generation method, for finding the proper size of bigtoe, is utilized by varying the bigtoe size. There are two requirements of robot design: go straight and stay within setting conditions. The simulation results of all small biped robot models which have the different bigtoe sizes can walk within setting conditions. There is only one model its bigtoe width per foot width ratio equals 0.28 (or 28% of foot width) has the longest walking distance. Moreover, this ratio is equal to the ratio of humans foot.

Abstract: In this paper, a method to generate the humanoid robots gait intelligently is put forward to solve the problem of poor performance of robot walking. The key idea in this proposed method is to adapt the transmutative humans gait to robot walking. Firstly, the character of the humans gait is acquired by researching a mass of gait data. Then, the typical gait signal is obtained which can be used to generate various gait signals. Finally, this method is proved to be effective by comparing the nature signals and the signal which is obtained by this method.

Abstract: During the design of biped robot HEUBR_1, a new structure of tandem and parallel connection is used in lower-limbs, adding toe-joints to feet. In order to make sure the rationality of humanoid structure design and feasibility of the humanoid gait planning, we built the simulating model of biped robot HEUBR_1 by using software ADAMS. The simulating model of biped robot HEUBR_1 walked stably with toe-joints in fictitious surrounding, which used the motion data exported by humanoid gait planning. During humanoid gait simulation, the biped robot kinematic and dynamical characteristics were achieved. Simulation indicates that the structure of tandem and parallel connection is rational and the method of humanoid gait planning is feasible. Humanoid walking with toe-joints has the characteristic: balanced motion, lower energy and small impact on feet. Simulated data of steady walking will be used as reference for biped robot HEUBR_1 walking experiments.

Abstract: Abstract: Purpose：By investigating the variation of the human walking gait kinematics with respect to the foot deformation constraint, prove that bionic design of feet are the necessity for biped robots to imitate human walking better in terms of flexibility, stability and efficiency. The results will be significant for future research and development of biped robots. Methods: A human being was assumed as a perfect biped robot which had ideal motion drive and control. The walking gait parameters of two healthy men with foot deformation unconstrained and constrained were tested respectively by the inertia motion capture suit, and then they were processed by programming and analyzed by comparison. Results: The data analysis showed that when subjects walked with foot deformation constrained, their angular displacements of lower limb joints generally increased, the curves of angular velocity and accelerations fluctuated in certain walking phases, the walking pace and stride length decreased obviously, the single support phase shortened while the double support phase lengthened. At the same time, subjects felt subjectively that their body motion was less flexible, the walking posture was difficult to control, and the walking stability was more strenuous to keep. Conclusion: Combining the logical analogies with the detailed experimentation results, it is inferred that biped robots with rigid feet will have to suffer awkward and unstable walking gait, heavier and strenuous steps, and lower energy efficiency while walking. The paper concludes the necessity of bionic design of the robot feet for improving the walking quality of the biped robots. The conclusion and the experiment data will be of significant value for future work of robot design and evaluation.

Abstract: Walking robot has complicate structure and strong ability to adapt ground conditions, and it is difficult to control. To realize dynamic walking of the humanoid robot, we have to establish robot dynamic models, design the control algorithm for gait and the stability postures. In this paper, study dynamic model and control system of a 7-links biped robot, build parameterized simulation model of biped walking robot, proceed gait planning and simulation experiments in the simulation surrounding, and get some experiment results. Compare the experiment data with the theoretic stable region and confirm that the biped walking robot as leg mechanism has good stability of static walking, and provide theoretic and data information for further work.

Abstract: With human characteristics of the structure of lower limb joints and simplify them, 12 degrees of freedom was equipped with for the lower extremities of biped walking robot. motion model is established and used to elaborate the movement characteristics in sagittal and lateral plane according to a particular mechanism of robot. The stability of robot in two or there dimensions is analyzed through ZMP principles and the calculation formula and measuring methods of corresponding ZMP are also concluded, Gait design data will be taken into the virtual prototype and make motion Simulation for gait, then get the simulation animation of walking straight, static turning and moves upstairs, This paper expounds the possibility of generating smooth walking trajectory with cubic interpolation. Using the dynamics simulation software to simulate the robot, the results show that the robot has the theory of stable gait, The control accuracy of joints position and the realization of desired purposes of the robot system.

Abstract: To realizing the imitation control of the biped humanoid robot, synchronous question is the core problem. Falling time of the robot and reflecting time of the operator both are the components which to real-time control of the robot. If the robot can walk well in limited time, between the two parts time questions, communication time need us to analyze. Based on the imitation control structure of our robot control system, characters of control model and communication system were studied and conclusions show that synchronous control for a robot by a human is difficult to realize and some other stable control methods need to add in the research.