Hua Zhong

Bio: Hua Zhong is an academic researcher from Shenyang Institute of Automation. The author has contributed to research in topics: Humanoid robot & Control system. The author has an hindex of 4, co-authored 5 publications receiving 26 citations.

Dynamic Stability Analyses Based on ZMP of a Wheel-based Humanoid Robot

Abstract: For wheel-based humanoid robot, the dynamic stability is also an important question just like for biped robot. This paper unites the new recursive Newton-Euler method for dynamic modeling and the ZMP concept and then obtains the ZMP model of the robot. The merit of this model is that it is a function of the position, velocity and acceleration of joints in joint space and easier to realize realtime control due to less calculation. Calculation and simulation show that the waist motion takes the main effect on the dynamic stability of the robot. Using the compensation of motion of the waist, the robot can realize dynamic motion. This paper also presents the concepts of the valid stable region and stable degree for the wheel-based robot.

Design and realization of control system of humanoid robot

Abstract: Aimed at structure of humanoid robot and requirements for control performance, this paper designs and realizes joint controller based on CAN bus, and structures an effective credible control system by connecting all joint controllers, force sensors, task management computer and upper limbs control computer together; and realizes the transmission of audio and video information by wireless LAN; constitutes whole control system of humanoid robot. Characteristics of the system are simple structure, high reliability, good real-time, and friendly human-machine interface. This paper includes mainly: overall structure of the humanoid robot, design and implement of controller, topology of control system, and bring forward some imaginations to enhance performance of the control system

Design and Implementation of Humanoid Robot Controller Based on CAN

Abstract: Aiming at humanoid robot structure and requirement for control performance, this paper designs and realizes joint controller based on CAN, and structures an effective credible control system by connecting controllers, force sensors and harmonious level computer together. This paper includes mainly: overall structure of the system, design and implementation of hardware and software, topology of control system, and bring forward some imaginations to enhance performance of the system

Control and simulation on the waist mechanism of a humanoid robot based on dynamic model

Abstract: The wheel-based humanoid robots with waist mechanism have large workspace and high agility. The humanoid robot in this paper has a waist mechanism with two parallel driving motors. The waist mechanism connects the vehicle with the trunk of the humanoid robot. The dynamic characteristic of the waist mechanism is affected by the dynamic characteristic of arms and vehicle and the external forces or torques, as well as by the motion of its own. This paper firstly built the whole dynamic model of the humanoid robot using the effective Newton-Euler Algorithm and then built the dynamic model of the waist mechanism through simplifying the whole dynamic model without consideration of coupling motion of the joints. The simplified dynamic model expresses the dynamic relation among the vehicle, waist and arms of the humanoid robot, minimizes the calculation and is convenient for realizing the control algorithm based on the dynamic model. This paper presented the PD control and the calculated torques method for compensating the torque disturb as the control strategy of the waist mechanism based on its dynamic model. The simulation shows the control algorithm remarkably improves the position tracing precision of the waist mechanism and improves the work precision of the humanoid robot.

Role of Osmotic Regulation and Cryoprotectant Substances in the Freezing Tolerance of Alfalfa in Cold, Dry Conditions

Abstract: Background: Freezing temperatures are a limiting factor hindering the survival of alfalfa (Medicago sativa L.) through winter. Soil drought also damages alfalfa crowns and can affect their regeneration. Therefore, it is important to determine the effects of cold, dry conditions on alfalfa to develop effective water management strategies in winter. Methods: Cold, dry conditions were established in the laboratory and the freezing tolerance of crowns was compared between the alfalfa cultivars ‘WL440HQ’ and ‘ZhaoDong’. The degree of freezing tolerance was estimated on the basis of relative electrolyte leakage and semi-lethal temperature. The effects of cold, dry conditions on alfalfa crowns were determined by investigating the rate of water loss and the concentrations of soluble sugars (which function as cryoprotectants) and betaine and proline (which function as osmoregulation substances). Result: Compared with crowns of ‘ZhaoDong’, those of ‘WL440HQ’ showed a higher water loss rate in cold, dry conditions and were irreversibly damaged and their freezing tolerance was severely affected. In comparison, crowns from ‘ZhaoDong’ showed a lower water loss rate and lower relative electrolyte leakage under cold, dry conditions and their freezing tolerance was not significantly affected. The higher water loss rate and lower freezing tolerance were the direct causes of death of ‘WL440HQ’, the cultivar with a higher fall dormancy score. In cold, dry conditions, the content of proline, an osmotic regulation substance, increased in response to soil water deficit and may have improved the ability to withstand freezing temperatures by preventing rapid water loss. In addition, sucrose, fructose, galactose and stachyose contents in the crown increased under cold, dry conditions and may have enhanced freezing tolerance because of their function as cryoprotectants. The results of this study indicate that maintaining soil moisture within the range suitable for the growth of crowns is important for the successful overwintering of alfalfa.

Linear model predictive control of the locomotion of Pepper, a humanoid robot with omnidirectional wheels

Abstract: The goal of this paper is to present a new realtime controller based on linear model predictive control for an omnidirectionnal wheeled humanoid robot. It is able to control both the mobile base of the robot and its body, while taking into account dynamical constraints. It makes it possible to have high velocity and acceleration motions by predicting the dynamic behavior of the robot in the future. Experimental results are proposed on the robot Pepper made by Aldebaran, showing good performance in terms of robustness and tracking control, efficiently managing kinematic and dynamical constraints.

Design of an embedded networking infrastructure for whole-body tactile sensing in humanoid robots

Abstract: Whole-body tactile sensing, especially when aimed at implementing tactile-based motion control, requires well-defined infrastructures. Requirements related to Real-Time operation, bandwidth and robustness must be carefully addressed. With respect to a tactile technology described in [2], this paper discusses a number of infrastructural solutions based on a Ethernet Real-Time protocol. Associated benefits and drawbacks are discussed. The identified models and solutions are compared both analytically and with extensive numerical simulations.

Omnidirectional wheeled humanoid robot based on a linear predictive position and velocity controller

Abstract: A humanoid robot with a body joined to an omnidirectional mobile ground base, equipped with: a body position sensor, a base position sensor and an angular velocity sensor to provide measures, actuators comprising at least 3 wheels located in the omnidirectional mobile base, extractors for converting sensored measures into useful data, a supervisor to calculate position, velocity and acceleration commands from the useful data, means for converting commands into instructions for the actuators, wherein the supervisor comprises: a no-tilt state controller, a tilt state controller and a landing state controller, each controller comprising means for calculating, position, velocity and acceleration commands based on a double point-mass robot model with tilt motion and on a linear model predictive control law, expressed as a quadratic optimization formulation with a weighted sum of objectives, and a set of predefined linear constraints.

Dynamic modeling of an anthropomimetic robot in contact tasks

Abstract: Considerations of energy efficiency and safe human-robot interaction have led to an increase in the exploitation of compliance in robotics, and much of this work has been inspired by biological systems As a consequence, new analytical tools are now required in order to enable the dynamic analysis of these novel compliant robots, especially in their interactions with the environment This paper extends the ‘Flier’ approach to show how it could be applied to the dynamic analysis of contact tasks involving a highly compliant biologically inspired robot – in this case an anthropomimetic robot, a humanoid with a human-like skeleton and artificial muscles, in which the joints are actuated by DC motors acting via compliant tendon transmissions First, a computer-based model of the robot’s dynamics is developed Various constraints are then introduced to describe the contacts (including impacts) with the ground, and with objects in the environment Simulation results are presented for two types of interactions w