Disturbance rejection by online ZMP compensation

Robotica ◽  
2008 ◽  
Vol 26 (1) ◽  
pp. 9-17 ◽  
Author(s):  
Vadakkepat Prahlad ◽  
Goswami Dip ◽  
Chia Meng-Hwee

SUMMARYA novel method of Zero-Moment-Point (ZMP) compensation is proposed to improve the stability of locomotion of a biped, which is subjected to disturbances. A compensating torque is injected into the ankle-joint of the foot of the robot to improve stability. The value of the compensating torque is computed from the reading of the force sensors located at the four corners of each foot. The effectiveness of the method is verified on a humanoid robot, MANUS-I. With the compensation technique, the robot successfully rejected disturbances in different forms. It carried an additional weight of 390 gm (17% of body weight) while walking. Also, it walked up a 10° slope and walked down a 3° slope.

2012 ◽  
Vol 197 ◽  
pp. 415-422 ◽  
Author(s):  
Hong Liu ◽  
Qing Sun

It is a great challenge to plan motion for humanoid robots in complex environments especially when the terrain is cluttered and discrete. To address this problem, a novel method is proposed in this paper by planning the gait according to the stance sequence and ZMP (Zero Moment Point) reference. It consists of two components: an adaptive footstep planner and a walking pattern generator. The adaptive footstep planner can generate the stance path according to the walking rules and adjust the orientation of body relevantly. As the footstep locations are determined, Linear Inverted Pendulum Model (LIPM) is used to generate the walking pattern with a moving ZMP reference. As demonstrated in experiments on the humanoid robot HOAP-2, our method can successfully plan footstep trajectories as well as generate the stable and natural-looking gait in typical cluttered and discrete environments.


2019 ◽  
Vol 6 ◽  
pp. 83-94
Author(s):  
Jesus E. Fierro P. ◽  
J. Alfonso Pamanes G. ◽  
Victor De-Leon-Gomez

The commercial Nao humanoid robot has 11 DOF in legs. Even if these legs include 12 revolute joints, only 11 actuators are employed to control the walking of the robot. Under such conditions, the mobility of the pelvis and that of the oscillating foot are mutually constrained at each step. Besides, the original gait provided by the manufacturer company of the Nao employs only single support phases during the walking. Because of both issues, the reduced mobility in legs and the use of only single support phases, the stability of the walking is affected. To contribute to improving such stability, in this paper an approach is proposed that incorporates a double support phase and a gait based on cycloidal time functions for motions of the pelvis and those of the oscillating foot. To assess the stability of the walking an index is applied, which is based on the notion of zero-moment point (ZMP) of the static foot at each step. Results of experimental tests show that the proposed gait enhances the stability of the robot during the walking.


2011 ◽  
Vol 201-203 ◽  
pp. 1978-1982
Author(s):  
Tie Jun Zhao

This research is aimed at dynamically stable motion and safety of mobile humanoid robots expected to work in a human living space. The mechanism of the mobile humanoid robot YIREN is described. A highly flexible anthropomorphic 7-DOF robotic arm and a new waist configuration with parallel driving motor are developed. Because the dynamitic behavior of manipulator and waist has an effect on the stability of mobile humanoid robots, the dynamitic model is built. By using the zero moment point, dynamic effect of the waist is obtained. A basic control method of whole body cooperative dynamic moving is proposed that uses waist cooperative motion to compensate for moment generated by the trajectory of the arms and the correctness of analysis is verified by experiments.


2013 ◽  
Vol 373-375 ◽  
pp. 242-245 ◽  
Author(s):  
Yunn Lin Hwang ◽  
Chien Hsin Chen ◽  
Shen Jenn Hwang ◽  
Nguyen Xuan Mai

The main objective of this paper is to simulate the mobility of humanoid robot. Simulation method implemented by using RecurDyn, one can analyze the kinematics and dynamics of BIOLOID humanoid robot. Moreover, the analysis of mobility will be discussed. In this paper, the Zero-Moment Point and Forward Dynamics methods are also introduced to the dynamic analysis of humanoid robot. Finally, the simulation results show that the algorithms developed in this paper can efficiently enhance the stability of the humanoid robot.


Author(s):  
Seungmoon Song ◽  
Young-Jae Ryoo ◽  
Dennis W. Hong

In this paper, we propose and demonstrate an omnidirectional walking engine that achieves stable walking using feedback from an inertial measurement unit (IMU). The 3D linear inverted pendulum model (3D-LIPM) is used as a simplified model of the robot, the zero moment point (ZMP) criterion is used as the stability criterion, and only the feedback from the IMU is utilized for stabilization. The proposed walking engine consists of two parts; the omnidirectional gait generator, and the stability controller. ZMP equations, derived based on the 3D-LIPM, are used in the omnidirectional gait generator. The solutions of the differential equations are directly used which reduces the computation cost compare to other existing methods. Two kinds of feedback controllers are implemented for the stability controller; one is the indirect reference ZMP controller, and the other is the indirect joint controller. The walking engine is tested on a lightweight, full-sized, 21-degree-of-freedom (DOF) humanoid robot CHARLI-L (Cognitive Humanoid Autonomous Robot with Learning Intelligence, version Lightweight) which stands 141 cm tall and weighs only 12.7 kg. The design goals of CHARLI-L are low development cost, lightweight, and simple design, which all match well with the proposed walking engine. The results of the experiments present the efficacy of our approach.


Fuel ◽  
2021 ◽  
Vol 292 ◽  
pp. 120315
Author(s):  
Feifei Wang ◽  
Pengfei Li ◽  
Jianchun Mi ◽  
Ziyun Shu

2013 ◽  
Vol 846-847 ◽  
pp. 190-194
Author(s):  
Shu Jun Yin ◽  
Xue Ren Li ◽  
Ji Geng Luo

The paper designs a three-phase high voltage power supply system based on active disturbance rejection controller which make single-chip microcomputer ATmega128 as the main control chip and the system improve the stability and control precision of dust removing power. Engineering practice shows that, the DC power supply system has the advantages of convenient operation, high work efficiency, system stability.


2016 ◽  
Vol 25 (06) ◽  
pp. 1650061 ◽  
Author(s):  
Zhen Shao ◽  
Zhengrong Xiang

This paper concerns the design of an observer-based repetitive control system (RCS) to improve the periodic disturbance rejection performance. The periodic disturbance is estimated by a repetitive learning based estimator (RLE) and rejected by incorporation of the estimation into a repetitive control (RC) input. Firstly, the configuration of the observer-based RCS with the RLE is described. Then, a continuous–discrete two-dimensional (2D) model is built to describe the RCS. By choosing an appropriate Lyapunov functional, a sufficient condition is proposed to guarantee the stability of the RCS. Finally, a numerical example is given to verify the effectiveness of the proposed method.


Obesity Facts ◽  
2021 ◽  
pp. 1-7
Author(s):  
Liesbet Trenson ◽  
Sander Trenson ◽  
Falco van Nes ◽  
Carolien Moyson ◽  
Matthias Lannoo ◽  
...  

<b><i>Introduction:</i></b> Obesity is a global health challenge, and pharmacologic options are emerging. Once daily subcutaneous administration of 3 mg liraglutide, a glucagon like peptide-1 analogue, has been shown to induce weight loss in clinical trials, but real-world effectiveness data are scarce. <b><i>Methods:</i></b> It is a single-centre retrospective cohort study of patients who were prescribed liraglutide on top of lifestyle adaptations after multidisciplinary evaluation. In Belgium, liraglutide is only indicated for weight management if the BMI is &#x3e;30 kg/m<sup>2</sup> or ≥27 kg/m<sup>2</sup> with comorbidities such as dysglycaemia, dyslipidaemia, hypertension, or obstructive sleep apnoea. No indication is covered by the compulsory health care insurance. Liraglutide was started at 0.6 mg/day and uptitrated weekly until 3 mg/day or the maximum tolerated dose. Treatment status and body weight were evaluated at the 4-month routine visit. <b><i>Results:</i></b> Between June 2016 and January 2020, liraglutide was prescribed to 115 patients (77% female), with a median age of 47 (IQR 37.7–54.0) years, a median body weight of 98.4 (IQR 90.0–112.2) kg, a BMI of 34.8 (IQR 32.2–37.4) kg/m<sup>2</sup>, and an HbA1c level of 5.6%. Five (4%) patients did not actually initiate treatment, 9 (8%) stopped treatment, and 8 (7%) were lost to follow-up. At the 4-month visit, the median body weight had decreased significantly by 9.2% to 90.8 (IQR 82.0–103.5) kg (<i>p</i> &#x3c; 0.001). Patients using 3.0 mg/day (<i>n</i> = 60) had lost 8.0 (IQR 5.8–10.4) kg. The weight loss was similar (<i>p</i> = 0.9622) in patients that used a lower daily dose because of intolerance: 7.4 (IQR 6.2–9.6) kg for 1.2 mg (<i>n</i> = 3), 7.8 (IQR 4.1–7.8) kg for 1.8 mg (<i>n</i> = 16), and 9.0 (IQR 4.8–10.7) kg for 2.4 mg/day (<i>n</i> = 14). Weight loss was minimal if liraglutide treatment was not started or stopped prematurely (median 3.0 [IQR 0.3–4.8] kg, <i>p</i> &#x3c; 0.001, vs. on treatment). Further analysis showed an additional weight reduction of 1.8 kg in the patients that had started metformin &#x3c;3 months before the start of liraglutide (<i>p</i> &#x3c; 0.001). The main reasons for liraglutide discontinuation were gastrointestinal complaints (<i>n</i> = 5/9) and drug cost (<i>n</i> = 2/9). <b><i>Conclusion:</i></b> In this selected group of patients, the majority complied with liraglutide treatment over the initial 4-month period and achieved a significant weight loss, irrespective of the maximally tolerated maintenance dose. Addition of metformin induced a small but significant additional weight loss.


Sign in / Sign up

Export Citation Format

Share Document