This paper is devoted to the permanence of the concept of Zero-Moment Point, widelyknown by the acronym ZMP. Thirty-five years have elapsed since its implicit presentation (actually before being named ZMP) to the scientific community and thirty-three years since it was explicitly introduced and clearly elaborated, initially in the leading journals published in English. Its first practical demonstration took place in Japan in 1984, at Waseda University, Laboratory of Ichiro Kato, in the first dynamically balanced robot WL-10RD of the robotic family WABOT. The paper gives an in-depth discussion of source results concerning ZMP, paying particular attention to some delicate issues that may lead to confusion if this method is applied in a mechanistic manner onto irregular cases of artificial gait, i.e. in the case of loss of dynamic balance of a humanoid robot. After a short survey of the history of the origin of ZMP a very detailed elaboration of ZMP notion is given, with a special review concerning “boundary cases” when the ZMP is close to the edge of the support polygon and “fictious cases” when the ZMP should be outside the support polygon. In addition, the difference between ZMP and the center of pressure is pointed out. Finally, some unresolved or insufficiently treated phenomena that may yield a significant improvement in robot performance are considered.

https://www.techfak.uni-bielefeld.de/~rhaschke/lehre/WS04/humanoids/papers/zmp-review.pdf

Zero-moment point — thirty five years of its life

This study emphasizes the need for standardized measurement tools for human robot interaction (HRI). If we are to make progress in this field then we must be able to compare the results from different studies. A literature review has been performed on the measurements of five key concepts in HRI: anthropomorphism, animacy, likeability, perceived intelligence, and perceived safety. The results have been distilled into five consistent questionnaires using semantic differential scales. We report reliability and validity indicators based on several empirical studies that used these questionnaires. It is our hope that these questionnaires can be used by robot developers to monitor their progress. Psychologists are invited to further develop the questionnaires by adding new concepts, and to conduct further validations where it appears necessary.

/pdf/measurement-instruments-for-the-anthropomorphism-animacy-55eaghvgd4.pdf

Measurement instruments for the anthropomorphism, animacy, likeability, perceived intelligence, and perceived safety of robots

In the nearly six decades since researchers began to explore methods of creating them, exoskeletons have progressed from the stuff of science fiction to nearly commercialized products. While there are still many challenges associated with exoskeleton development that have yet to be perfected, the advances in the field have been enormous. In this paper, we review the history and discuss the state-of-the-art of lower limb exoskeletons and active orthoses. We provide a design overview of hardware, actuation, sensory, and control systems for most of the devices that have been described in the literature, and end with a discussion of the major advances that have been made and hurdles yet to be overcome.

Lower Extremity Exoskeletons and Active Orthoses: Challenges and State-of-the-Art

For measuring machines and machine tools, geometrical accuracy is a key performance criterion. While numerical compensation is well established for CMMs, it is increasingly used on machine tools in addition to mechanical accuracy. This paper is an update on the CIRP keynote paper by Sartori and Zhang from 1995 [Sartori S, Zhang GX (1995) Geometric error measurement and compensation of machines, Annals of the CIRP 44(2):599–609]. Since then, numerical error compensation has gained immense importance for precision machining. This paper reviews the fundamentals of numerical error compensation and the available methods for measuring the geometrical errors of a machine. It discusses the uncertainties involved in different mapping methods and their application characteristics. Furthermore, the challenges for the use of numerical compensation for manufacturing machines are specified. Based on technology and market development, this work aims at giving a perspective for the role of numerical compensation in the future.

Geometric error measurement and compensation of machines : an update

Robot navigation in the presence of humans raises new issues for motion planning and control when the humans must be taken explicitly into account. We claim that a human aware motion planner (HAMP) must not only provide safe robot paths, but also synthesize good, socially acceptable and legible paths. This paper focuses on a motion planner that takes explicitly into account its human partners by reasoning about their accessibility, their vision field and their preferences in terms of relative human-robot placement and motions in realistic environments. This planner is part of a human-aware motion and manipulation planning and control system that we aim to develop in order to achieve motion and manipulation tasks in the presence or in synergy with humans.

/pdf/a-human-aware-mobile-robot-motion-planner-1miap4wyrt.pdf

A Human Aware Mobile Robot Motion Planner

When robots coexisting with humans are designed, it is important to evaluate the influence of the shape and size of the robots and their motions on human sense of security. For this purpose, an evaluation system of human sense of security for coexisting robots using virtual reality is discussed. Virtual robots are visually presented to a human subject through a head mounted display; the subject and the robots coexist in the virtual world. Some kinds of physiological indices of the subject are measured, he answers the questionnaire about his impression of the robots, and his sense of security is evaluated. Because of using virtual reality technique, the shape and size of the robots and their motions can be easily changed and tested. In the present report, pick and place motion of humanoid robots is evaluated. As a result of analyzing the questionnaire, it is found that turning the body coordinating with the arm gives good impression on humans.

Evaluation of human sense of security for coexisting robots using virtual reality. 1st report: evaluation of pick and place motion of humanoid robots

This paper discusses pushing a heavy object by a humanoid robot. We modify the whole body motion considering the hand reflecting forces for the walking pattern of a humanoid robot. By assuming that linear and angular momentum of a humanoid robot are calculated, we define the projection of the Center of the Mass(CoM) as” Dynamically Complemental Zero Moment Point(DCZMP)”, when external forces act to the end-effectors. We propose a new method using the DCZMP for the modification control of CoM position with balancing control. The robot can keep the dynamical balance considering the DCZMP and the walking velocity in both single and double support phase. In addition, for controlling pushing force, we implement an impedance controller with the manipulation and walking velocity controller. The effectiveness of the proposed method is confirmed by simulations and experiments.

Pushing an Object Considering the Hand Reflect Forces by Humanoid Robot in Dynamic Walking

A real-time control method for a humanoid in mobile manipulation, doing tasks with its arms while moving, is proposed. The arm tips always follow their desired position with external force applied by impedance control, for carrying out a given task with the arms. An evaluation function consisting of not only stability but also arm manipulability-both are important for mobile manipulation-is defined; the humanoid controls its body and legs so that this evaluation may be optimal. As a result, the humanoid autonomously steps or keeps standing, coordinating with the arm tips motion. The effectiveness and usefulness of the proposed method are ascertained by computer simulations on a humanoid of human-size and experiments using a small experimental robot.

Mobile manipulation of humanoids-real-time control based on manipulability and stability

In order to develop a high performance working robot, we design and develop a new robot based on the concept of "limb mechanism " for integration of legged locomotion and arm manipulation. The robot developed has six limbs which can be used for both locomotion and manipulation. The six limbs are set on vertices of regular hexagonal body so that this robot can have omnidirectional manipulability and mobility. We evaluate the stroke and the stability margin in all walking directions on six-legged and four-legged locomotion. As a result, this robot has higher omnidirectional mobility than conventional mechanisms.

Development of multi-limb robot with omnidirectional manipulability and mobility

A control method for humanoid robots of mobile manipulation is proposed. A robot autonomously steps or controls its body pose while performing various manipulation tasks with its hands; that enables dexterous and stable manipulation. Two hands always move along their desired trajectories by impedance control for carrying out a given task. Coordinating with this motion of the hands, the robot controls its body and legs so that arm manipulability and robot stability may increase. It determines the next foothold by evaluating manipulabilities of both arms, shape of stable region and moving direction. An evaluation function consisting of manipulabilities of both arms and static stability of the robot is defined, and the robot steps if the new double support state is better than the current one. Both in double and single support states, the robot controls its body pose using the support leg(s) so that this evaluation may be optimal. Various motions of a humanoid robot by the proposed method are simulated.

Kenji Inoue

Papers

Evaluation of human sense of security for coexisting robots using virtual reality. 1st report: evaluation of pick and place motion of humanoid robots

Pushing an Object Considering the Hand Reflect Forces by Humanoid Robot in Dynamic Walking

Mobile manipulation of humanoids-real-time control based on manipulability and stability

Development of multi-limb robot with omnidirectional manipulability and mobility

Mobile manipulation of humanoid robots-body and leg control for dual arm manipulation