Local on-line planning in biped robot locomotion amongst unknown obstacles

Robotica ◽  
2000 ◽  
Vol 18 (4) ◽  
pp. 389-402 ◽  
Author(s):  
M. Yagi ◽  
V. Lumelsky
Keyword(s):  
Center Of Mass ◽  
Biped Robot ◽  
Line Planning ◽  
Robot Locomotion ◽  
Stable Motion ◽  
Walking Pattern ◽  
Wide Range ◽  
Decision Making System ◽  
On Line ◽  
Zero Moment

The focus of this work is on sensor-based motion planning for a biped robot operating in a scene with unknown obstacles. Using on-line sensor information about its surroundings, the robot negotiates obstacles on its way. Depending on the obstacle's shape, size, and location, the decision-making system chooses an appropriate walking pattern. The robot then negotiates the obstacle and resumes stable motion. The walking pattern is chosen from a small number of precomputed patterns that together cover a reasonably wide range of possible situations. The overall control strategy is based on the concept of Zero Moment Point. Each precomputed pattern guarantees dynamically stable motion; its stability is obtained by adjusting the swing leg center of mass and hip position trajectories. The approach is fast enough for real-time implementation. Simulation experiments demonstrate stability of motion when negotiating various obstacles.

scholarly journals Stable walking of biped robot based on center of mass trajectory control

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 328-337
Author(s):  
Chenglin Jing ◽  
Jiajia Zheng
Keyword(s):  
Control System ◽  
Predictive Control ◽  
Simulation Experiment ◽  
Center Of Mass ◽  
Biped Robot ◽  
Human Walking ◽  
Walking Pattern ◽  
Adaptive Adjustment ◽  
Zero Moment ◽  
Robot Modeling

AbstractThe effect of center of mass (CoM) trajectory on stable walking of biped robot was studied in this study. The method of predictive control by controlling CoM trajectory to generate stable walking patterns was discussed, which simulated the principle of adjusting center of gravity in advance during human walking to adapt to the change of road conditions. As for uncertainty of robot modeling and the influence of environment, adding variable zero moment point for variable predictive control system can achieve self-adaptive adjustment of CoM trajectory to generate stable walking patterns. The simulation experiment results indicated that walking stability of biped robot was sensitive to the change of CoM trajectory. As long as CoM trajectory was adjusted well, stable walking of biped robot can be controlled even in the presence of disturbances. It is proved that the method of predictive control by controlling CoM motion to generate stable walking pattern is consistent with reality.

PLANNING OF SAGITTAL GAIT OF BIPED ROBOTS BASED ON MINIMUM MOTION ENERGY

2010 ◽  
Vol 07 (04) ◽  
pp. 635-667 ◽  
Author(s):  
KUO-YANG TU ◽  
MI-SHIN LIU
Keyword(s):  
Lower Limb ◽  
Optimal Trajectory ◽  
Biped Robot ◽  
Inverse Kinematic ◽  
Biped Robots ◽  
Motion Energy ◽  
Walking Pattern ◽  
Acceleration And Deceleration ◽  
Zero Moment ◽  
Kinetic And Potential Energies

Traditional planning of biped robot walking patterns solves optimal trajectory for minimizing energy consumption. However, a diversity of biped robot walking functions lead to a variety of walking types. The walking patterns to implement a variety of biped robot objectives should have enough parameters to cope with their functions. In this article, walking patterns based on two 4-3-4 polynomials for the trajectories of biped robot waist and lower limb are proposed. The main advantage of the walking pattern is that 4-3-4 polynomials containing the parameters of acceleration and deceleration for biped walking make the implementation of a variety of walking types possible. In the study, the prototype mechanism of a biped robot is designed. After that, the direct and inverse kinematic equations of the biped robot are derived. For studying motion energy of biped robots, kinetic and potential energies are also defined. Based on these definitions, the parameters of the biped robot trajectories for minimum motion energy are solved. The solution is summarized by a development procedure. In addition, the study of zero moment point (ZMP) during the biped robot in walking is included.

Heel-Contact Toe-Off Walking Pattern Generator Based on the Linear Inverted Pendulum

2016 ◽  
Vol 13 (01) ◽  
pp. 1650002 ◽  
Author(s):  
Yukitoshi Minami Shiguematsu ◽  
Przemyslaw Kryczka ◽  
Kenji Hashimoto ◽  
Hun-Ok Lim ◽  
Atsuo Takanishi
Keyword(s):  
Simple Model ◽  
Humanoid Robot ◽  
Inverted Pendulum ◽  
Center Of Mass ◽  
Pattern Generator ◽  
Walking Pattern ◽  
Heel Contact ◽  
Zero Moment ◽  
Two Stages ◽  
Multibody Dynamics Model

We propose a novel heel-contact toe-off walking pattern generator for a biped humanoid robot. It is divided in two stages: a simple model stage where a Linear Inverted Pendulum (LIP) based heel-contact toe-off walking model based on the so-called functional rockers of the foot (heel, ankle and forefoot rockers) is used to calculate step positions and timings, and the Center of Mass (CoM) trajectory taking step lengths as inputs, and a multibody dynamics model stage, where the final pattern to implement on the humanoid robot is obtained from the output of the first simple model stage. The final pattern comprises the Zero Moment Point (ZMP) reference, the joint angle references and the end effector references. The generated patterns were implemented on our robotic platform, WABIAN-2R to evaluate the generated walking patterns.

Walking Pattern Filter for Dynamic Biped Robot With SMA Actuators

Aerospace ◽  
2006 ◽  
Author(s):  
E. Tarkesh Esfahani ◽  
Mohammad Elahinia
Keyword(s):  
Biped Robot ◽  
Human Motion ◽  
Main Criterion ◽  
Biped Robots ◽  
Sma Actuators ◽  
Walking Pattern ◽  
Delay Times ◽  
Zero Moment ◽  
The Stability ◽  
The Given

In this paper we present a walking pattern filter for Shape Memory Alloy (SMA) actuated biped robots. SMAs are known for their slow response. The actuation speed limitation can potentially lead to stability problems for biped robots. This filter adapts the human motion for a SMA biped in order to have a stable walking pattern. The Zero Moment Point (ZMP) is used as a main criterion of the filter to guarantee the stability of the motion. The SMA actuators are designed based on the dynamic and kinematics data of the motion. The response time of each SMA actuator is modeled in order to estimate the behavior of the actuator in realizing the given trajectory. After applying the delay times to the motion new trajectories are generated and checked by the ZMP criterion. The output of the filter can generate smooth trajectories for the SMA biped robots. The filter furthermore guarantees the stability while mimicking the human motion. The filter provides a practical way to create stable walking patterns using SMA actuators.

Tip over avoidance control for biped robot

Robotica ◽  
2009 ◽  
Vol 27 (6) ◽  
pp. 883-889 ◽  
Author(s):  
Tang Qing ◽  
Xiong Rong ◽  
Chu Jian
Keyword(s):  
Inverted Pendulum ◽  
Biped Robot ◽  
Point Of View ◽  
Experimental Results ◽  
Stabilization Problem ◽  
Point Energy ◽  
Energy Point ◽  
Walking Pattern ◽  
Avoidance Control ◽  
Zero Moment

SUMMARYThis paper analyzes the stabilization problem from the energy point of view. Perturbations are detected by the gyros and categorized according to the constraints on the zero-moment point, energy, and walking pattern. Ankle torque is exerted to extend the linear inverted pendulum mode (LIPM). Compensation movement is computed according to the analysis on the energy of LIPM and the influence of disturbance to the energy. The experimental results from both the simulation and the physical robot not only proved effective but also explain various human reactions to disturbance in locomotion.

scholarly journals A Simple Yet Effective Whole-Body Locomotion Framework for Quadruped Robots

2020 ◽  
Vol 7 ◽  
Author(s):  
Gennaro Raiola ◽  
Enrico Mingo Hoffman ◽  
Michele Focchi ◽  
Nikos Tsagarakis ◽  
Claudio Semini
Keyword(s):  
Center Of Mass ◽  
Whole Body ◽  
Control Approach ◽  
Planning Strategy ◽  
Robot Locomotion ◽  
Quadruped Robots ◽  
Floating Base ◽  
Walking Pattern ◽  
Different Types ◽  
Postural Task

In the context of legged robotics, many criteria based on the control of the Center of Mass (CoM) have been developed to ensure a stable and safe robot locomotion. Defining a whole-body framework with the control of the CoM requires a planning strategy, often based on a specific type of gait and a reliable state-estimation. In a whole-body control approach, if the CoM task is not specified, the consequent redundancy can still be resolved by specifying a postural task that set references for all the joints. Therefore, the postural task can be exploited to keep a well-behaved, stable kinematic configuration. In this work, we propose a generic locomotion framework which is able to generate different kind of gaits, ranging from very dynamic gaits, such as the trot, to more static gaits like the crawl, without the need to plan the CoM trajectory. Consequently, the whole-body controller becomes planner-free and it does not require the estimation of the floating base state, which is often prone to drift. The framework is composed of a priority-based whole-body controller that works in synergy with a walking pattern generator. We show the effectiveness of the framework by presenting simulations on different types of simulated terrains, including rough terrain, using different quadruped platforms.

Recent Progress and Plans in Computer-Controlled High Resolution Electron Microscopy

1990 ◽  
Vol 48 (1) ◽  
pp. 154-155
Author(s):  
W.J. de Ruijter ◽  
Peter Rez ◽  
David J. Smith
Keyword(s):  
Electron Microscopy ◽  
Digital Processing ◽  
High Resolution Electron Microscopy ◽  
Objective Lens ◽  
Linear Filter ◽  
Contrast Transfer Function ◽  
Image Displacement ◽  
Spatially Resolved ◽  
Wide Range ◽  
On Line

Digital computers are becoming widely recognized as standard accessories for electron microscopy. Due to instrumental innovations the emphasis in digital processing is shifting from off-line manipulation of electron micrographs to on-line image acquisition, analysis and microscope control. An on-line computer leads to better utilization of the instrument and, moreover, the flexibility of software control creates the possibility of a wide range of novel experiments, for example, based on temporal and spatially resolved acquisition of images or microdiffraction patterns. The instrumental resolution in electron microscopy is often restricted by a combination of specimen movement, radiation damage and improper microscope adjustment (where the settings of focus, objective lens stigmatism and especially beam alignment are most critical). We are investigating the possibility of proper microscope alignment based on computer induced tilt of the electron beam. Image details corresponding to specimen spacings larger than ∼20Å are produced mainly through amplitude contrast; an analysis based on geometric optics indicates that beam tilt causes a simple image displacement. Higher resolution detail is characterized by wave propagation through the optical system of the microscope and we find that beam tilt results in a dispersive image displacement, i.e. the displacement varies with spacing. This approach is valid for weak phase objects (such as amorphous thin films), where transfer is simply described by a linear filter (phase contrast transfer function) and for crystalline materials, where imaging is described in terms of dynamical scattering and non-linear imaging theory. In both cases beam tilt introduces image artefacts.

A Wide Range Ge Gamma-Ray Spectrometer for on-Line Measurements of Reactor Cooling Water Activity

1977 ◽  
Vol 24 (1) ◽  
pp. 673-677 ◽  
Author(s):  
J. J. Lipsett ◽  
I. L. Fowler ◽  
R. J. Dinger ◽  
H. L. Malm
Keyword(s):  
Water Activity ◽  
Gamma Ray ◽  
Cooling Water ◽  
Gamma Ray Spectrometer ◽  
Wide Range ◽  
On Line

Estimation of the Thermodynamic Properties of Branched Hydrocarbons

2000 ◽  
Vol 122 (3) ◽  
pp. 147-152 ◽  
Author(s):  
Hui He ◽  
Mohamad Metghalchi ◽  
James C. Keck
Keyword(s):  
Thermodynamic Properties ◽  
Degrees Of Freedom ◽  
Statistical Thermodynamic ◽  
Motion Modes ◽  
Branched Alkanes ◽  
Branched Hydrocarbons ◽  
Wide Range ◽  
On Line ◽  
Kinetic Calculations ◽  
Good Agreement

A simple model has been developed to estimate the sensible thermodynamic properties such as Gibbs free energy, enthalpy, heat capacity, and entropy of hydrocarbons over a wide range of temperatures with special attention to the branched molecules. The model is based on statistical thermodynamic expressions incorporating translational, rotational and vibrational motions of the atoms. A method to determine the number of degrees of freedom for different motion modes (bending and torsion) has been established. Branched rotational groups, such as CH3 and OH, have been considered. A modification of the characteristic temperatures for different motion mode has been made which improves the agreement with the exact values for simple cases. The properties of branched alkanes up to 2,3,4,-trimthylpentane have been calculated and the results are in good agreement with the experimental data. A relatively small number of parameters are needed in this model to estimate the sensible thermodynamic properties of a wide range of species. The model may also be used to estimate the properties of molecules and their isomers, which have not been measured, and is simple enough to be easily programmed as a subroutine for on-line kinetic calculations. [S0195-0738(00)00902-X]

Health care Online

2000 ◽  
Vol 1 (2) ◽  
pp. 24-25
Keyword(s):  
Health Care ◽  
Health Care Policy ◽  
Central Government ◽  
Medical Profession ◽  
Medical Opinion ◽  
Proactive Approach ◽  
The United Kingdom ◽  
Wide Range ◽  
On Line ◽  
The Subject

The BMJ has always been recognised as a leading medical journal for a wide range of subjects, and has always been useful for nurses to access for up to date and current medical opinion. Recently the BMJ has diversified to take on a more political nature, with its content reflecting a more proactive approach to influencing health care policy in the United Kingdom by the medical profession. As such the BMJ has become extremely useful for identifying opinions of current ‘hot topics’ for nurses that are headline news such as nurse consultants, hospital administration and central government policy. However, one problem remains, trying to find the original copy in the library will remain difficult. After spending the best part of an hour to suddenly realise that ‘how silly you are for not realising that BMJ March 1997 is filed in the British Journal of Nursing section 1998!!’ is often a frustrating and demoralising experience - particularly if after finding the article you find it has nothing to do with the subject that you are researching. This problem is to be banished forever with the BMJ website. The full BMJ is available free on line. The excellent search engine is particularly useful and is accurate when matching target articles. All articles are available for ‘full text’ downloads free of charge.

Sign in / Sign up

Export Citation Format

Share Document