Zhangguo Yu

Zhangguo Yu
Beijing Institute of Technology | BIT · School of Mechanical Engineering

Professor

About

151
Publications
25,758
Reads
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915
Citations
Citations since 2016
88 Research Items
706 Citations
2016201720182019202020212022020406080100120140
2016201720182019202020212022020406080100120140
2016201720182019202020212022020406080100120140
2016201720182019202020212022020406080100120140
Introduction

Publications

Publications (151)
Article
Biped robots with dynamic motion control have shown strong robustness in complex environments. However, many motion planning methods rely on models, which have difficulty dynamically modifying the walking cycle, height, and other gait parameters to cope with environmental changes. In this study, a heuristic model-free gait template planning method...
Article
Compliance control is important for the realization of disturbance absorption in biped robots. However, under a sustained disturbance, compliance control causes the robot’s balance to deteriorate because of its floating base nature. Humans address this problem by resisting external disturbance. When pushed, a human will reconcile their posture with...
Article
Full-text available
To face the challenge of adapting to complex terrains and environments, we develop a novel wheel-legged robot that can switch motion modes to adapt to different environments. The robot can perform efficient and stable upright balanced locomotion on flat roads and flexible crawling in low and narrow passages. For passing through low and narrow passa...
Chapter
In order to improve the dynamic motion ability of the biped robot, a joint with high torque output and high backdrivability is required. In this paper, a new leg mechanism using a joint with continuously variable reduction ratio inspired by human joint structure is proposed. This mechanism possesses high actuation capability and high impact resista...
Article
Stability control for humanoid robots based on zero moment point (ZMP) control and impedance control are widespread. However, uncertain changes in the center of mass (CoM) height for ZMP control and specific regulation of the variable stiffness of impedance control have been challenging issues in previous studies. In this article, these two problem...
Article
Full-text available
The biped robot adjusts stepping variables (i.e., stride length and stepping duration) to achieve robust walking under perturbations. A novel method of integrating center of mass (CoM) stabilization control into the optimization of stepping variables was proposed in this article. The method contains offline and online procedures. In the offline pro...
Article
Full-text available
Biped robots are expected to be able to work in complex environments. However, these robots will inevitably fall at times and such falls may cause injury to the robot itself or to people nearby. Therefore, it is necessary to detect that the robot is falling to be able to warn the robot in sufficient time when it is about to fall and to switch its c...
Article
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Aiming at highly dynamic locomotion and impact mitigation, this paper proposes the design and implementation of a symmetric legged robot. Based on the analysis of the three-leg topology in terms of force sensitivity, force production, and impact mitigation, the symmetric leg was designed and equipped with a high torque density actuator, which was a...
Article
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This paper first introduces the guide-weight criterion into the topology optimization problems for maximization of the fundamental eigenfrequency of vibrating continuum structures. The traditional solid isotropic material with penalization model is modified to eliminate the artificial localized modes. Based on this modified model, the iteration for...
Article
Full-text available
The jumping motion of legged robots is an effective way to overcome obstacles in the rugged microgravity planetary exploration environment. At the same time, a quadruped robot with a manipulator can achieve operational tasks during movement, which is more practical. However, the additional manipulator will restrict the jumping ability of the quadru...
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To accelerate the convergence rate and obtain robust optimal results with clear profiles of structural topologies, this paper proposes a hybrid multi-population genetic algorithm (MPGA) and bi-directional evolutionary structural optimization (BESO) method for structural topology optimization. Each element in the design domain is treated as an indiv...
Article
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Knee-stretched walking is considered to be a human-like and energy-efficient gait. The strategy of extending legs to obtain vertical center of mass trajectory is commonly used to avoid the problem of singularities in knee-stretched gait generation. However, knee-stretched gait generation utilizing this strategy with toe-off and heel-strike has kine...
Article
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Jumping capability of humanoid robots can be considered as one of the cruxes to improve the performance of future humanoid robot applications. This paper presents an optimization method on a three-linkage system to achieve a jumping behavior, which is followed by the clarification of the mathematical modeling and motor-joint model with practical fa...
Article
The humanoid robot, one of the ideal unmanned systems, has the potential to perform tasks currently carried out by human workers in industry, manufacturing, service, and disaster response. In such complicated environments with unknown disturbances, compliance is important for a humanoid robot, especially a position-controlled one, to maintain balan...
Article
Full-text available
Legged robots imitating animals have become versatile and applicable in more application scenarios recent years. Most of their functions rely on powerful athletic abilities, which require the robots to have remarkable actuator capacities and controllable dynamic performance. In most experimental demonstrations, continuous hopping at a desired heigh...
Article
Full-text available
A method for the force-free control of humanoid robot joints is presented that meets human–machine cooperation functions of a humanoid robot. To ensure accurate torque control, the current loop of the permanent magnet synchronous motor was initially optimised and its dynamic response improved with a compensating back electromotive force. The motor...
Article
Full-text available
Load capacity is an important index to reflect the practicability of legged robots. Existing research into quadruped robots has not analyzed their load performance in terms of their structural design and control method from a systematic point of view. This paper proposes a structural design method and crawling pattern generator for a planar quadrup...
Conference Paper
Compliance is important for humanoid robots, especially a position-controlled one, to perform tasks in complicated environments where unexpected or sudden contacts will result in large impacts which may cause instability or destroy the hardware of robots. This paper presents a compliance control method based on viscoelastic model for humanoid robot...
Conference Paper
State estimation is an important part of biped robot control, but unreliable foot contact estimation would lead to inaccurate state estimation result. In this paper, to reduce the state estimation error caused by the inaccurate contact estimation, we propose a novel simplified contact probability estimator based on the force/torque sensor mounted o...
Article
Background: Leg muscle fatigue is the most important factor that affects walking endurance. Considering the legs act as actuators in alternate contact with the ground during walking, the ground reaction force (GRF) of each leg can indirectly reflect the strength of leg muscles. However, it is not clear how the elastically-suspended backpack (ESB)...
Chapter
In this paper, a jumping control method is proposed as based on Virtual Model Control (VMC). The virtual force and torque acting on the trunk are used to control the jumping height, speed, and posture. VMC is used to calculate the driving torque of joints to exert the desired virtual force and torque. Each jumping cycle is divided into three states...
Article
Full-text available
Sports robots have become a popular research topic in recent years. For table-tennis robots, ball tracking and trajectory prediction are the most important technologies. Several methods were developed in previous research efforts, and they can be divided into two categories: physical models and machine learning. The former use algorithms that consi...
Article
Full-text available
Most existing motion control methods for humanoids aim at avoiding falling. However, the humanoid is generally an unstable system that cannot completely avoid falling and it is difficult to cope with the sudden fall of a robot. This paper designs a planning method of fall protection for humanoids according to the human falling motion. This method c...
Conference Paper
A humanoid robot operated with position control has the characteristic of high trajectory tracking accuracy. However, its ability to adapt to complex environments is insufficient during walking due to the rigidity of the joint. More complex methods of control are needed when walking on uneven ground. A humanoid robot operated using torque control h...
Chapter
In this paper, we introduce a gait transition method for a humanoid robot when the robot needs to recover after falling down. Muli-contact model is built to describe the complex interaction between the robot and environment. Valid stable region and balance control based on whole-body dynamic are used to guarantee the stability during the gait trans...
Article
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The muscles of the lower limbs directly influence leg motion, therefore, lower limb muscle exercise is important for persons living with lower limb disabilities. This paper presents a medical assistive robot with leg exoskeletons for locomotion and leg muscle exercises. It also presents a novel pedal-cycling actuation method with a crank-rocker mec...
Chapter
Humanoid robots should prevent damage during falling forwards, which will improve the ability of serving people on various occasions. In this paper, we analyze different landing positions, and propose a falling forwards protection strategy for humanoid robots. Falling forwards is divided into two phases: the knee landing phase and the chest landing...
Chapter
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This paper presents the historical development of the humanoid robots of the BHR series, ranging from the first Chinese humanoid robot BHR-1 to the current sixth generation BHR-6P. The early BIT (Beijing Institute of Technology) activities in robotics have laid a foundation for the development of the BHR series. The success of the first prototype o...
Article
Full-text available
Slip often occurs in humanoid robot walking, especially when the robot walks on a low friction floor or walks fast. Unexpected slip may cause the robot to fall and then sustain damage. In real environments, rotational and translational slip phenomena can happen during biped walking. Previous studies have mainly focused on solving these problems ind...
Article
Full-text available
The most important feature of this paper is to transform the complex motion of robot turning into a simple translational motion, thus simplifying the dynamic model. Compared with the method that generates a center of mass (COM) trajectory directly by the inverted pendulum model, this method is more precise. The non-inertial reference is introduced...
Article
In this paper, a master-slave control system is proposed and applied in an intention-actuated exoskeletal robot to assist user locomotion and lower extremity rehabilitation simultaneously. In particular, to increase users’ sense of participation, the motion of the exoskeleton and the wheelchair, which is denoted as slave motion in this study, is ac...
Conference Paper
In this paper, a falling motion planning for humanoid robots is proposed as inspired from human falling in order to decrease the impact force significantly. Firstly, motion data of human falling are obtained from a motion track system. Then, two falling motion primitives, namely, knee bending with stretching and hip bending with stretching are iden...
Article
Full-text available
The remarkable ability of humans to perform jump maneuvers greatly contributes to the improvements of the obstacle negotiation ability of humans. The paper proposes a jumping control scheme for a bipedal robot to perform a high jump. The half-body of the robot is modeled as three planar links and the motion during the launching phase is taken into...
Article
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This article presents a design of novel wheelchair with a leg exoskeleton for locomotion that can be powered by user legs through a cycling action. In addition, the control system is designed with leg-motion assistance for lower limb muscles to perform exercise during wheelchair motion, targeting elderly persons and users with partial hemiplegia. T...
Article
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In order to better adapt to human living environment for improving the ability of serving people on various occasions, humanoid robots need to prevent themselves from being severely damaged during falling backward. In this article, we have study the law of human falling motion with a motion capture system and propose a minimized falling damage meth...
Article
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...
Article
Full-text available
Human-like features, like toe-off, heel-strike, and disturbance rejection, can enhance the performance of bipedal robots. However, the required control strategies for these motions influence each other, and few studies have considered them simultaneously. Humans can walk stably with toe-off and heel-strike even after experiencing disturbances. Thus...