A method for haptic motion abstraction and display based on action force directionality

Robots working in an unknown environment or a human environment have been investigated for years in the field of motion control. For the next‐generation robots, human and robot interaction technologies are needed. In particular, abstractions of human motion and motion display technologies are important. This paper proposes a method for haptic motion abstraction based on action force directionality. The action force is measured by using a master–slave robot hand system which is bilaterally controlled. Human motion is abstracted as action modes and action ratios, which are calculated from the action force directionality. Action modes express action force directionality, and action ratios express the amplitude of each action mode. Action modes are valid for motion preservation, identification of humans, and motion display systems. Thus, as one of the application of action modes, a method for motion display is also proposed. A motion display control system is designed based on action modes and action ratios. This control system presents the desired action force directionality as a velocity response depending on the human action force. The validity of the proposed method is shown by the experimental results. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 176(2): 62–70, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21126     

Robotics‐based telepresence using multi‐modal interaction for individuals with visual impairments

Although many assistive devices have been developed and utilized to aid in daily living, the most general assistive means for individuals with visual impairments are the walking cane and guide dogs. These assistive means are effective in assisting the user in navigating within an environment; however, the navigation space is limited to the proximal environment of the user. Thus, in this paper, we discuss a method to increase the range of accessibility to a remote environment through robotic embodiment that enables teleoperation and teleperception through multi‐modal feedback. In order to transform remote spatial information into a non‐visual modality, we present a framework for utilizing an RGB‐D‐based depth camera, a mobile robot, and a haptic interface for 3D haptic rendering to accomplish the goal of haptic exploration of a remote environment. Experiments with three different control methods for robot interaction are designed for users with and without visual impairments. Several hypothesis are built to study the correlation between control/feedback modality and performance in telerobotic operations. Results show that users performed best when combining semi‐autonomous navigation with 3D haptic exploration and also rated their experience with our system as fairly good. Copyright © 2014 John Wiley & Sons, Ltd.     

Advanced motion control by multi‐sensor‐based disturbance observer

Motion control has been widely used in industry applications. One of the key technologies of motion control is a disturbance observer, which quarries a disturbance torque of a motion system and realizes a robust acceleration control. The disturbance observer can observe and suppress the disturbance torque within its bandwidth. Recent motion systems have begun to spread in society and are required to have the ability to make contact with the unknown environment. Such a haptic motion requires a much wider bandwidth. However, since the conventional disturbance observer attains the acceleration response by the second‐order derivative of position response, the bandwidth is limited because of the derivative noise. This paper proposes a novel structure of a disturbance observer. The proposed disturbance observer uses an acceleration sensor for enlargement of bandwidth. Generally, the bandwidth of an acceleration sensor is from 1 Hz to more than 1 kHz. To cover the DC range, the conventional position sensor‐based disturbance observer is integrated. Thus, the performance of the proposed multisensor based disturbance observer (MSDO) is superior to the conventional one. The MSDO is applied to position control (infinity stiffness) and force control (zero stiffness). The experimental results show the viability of the method proposed. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Performance Evaluation of an Image‐Space Observer‐Based Visual Servoing System

In recent years, robots have come to be required to operate in various environments and situations. Therefore, robots have to recognize the environment they are in and adapt to any situations that present themselves. The purpose of this research is to increase the tracking speed and robustness of a visual servoing system. A 3‐link planar manipulator provided with a CCD camera is used to track the target. In order to track the target, an image‐based tracking method, suitable for high‐speed tracking, is used. This paper proposes an image‐space observer (IOB), which compensates disturbances in the image space. A zero‐order hold is introduced to the IOB to enhance the performance of the visual servoing system. The validity of the proposed method is confirmed through experiments.     

Two‐Degree‐of‐Freedom Robust Temperature Control of Peltier Device Based on Heat Disturbance Observer

Recently, the Peltier device has been attracting attention as a haptic device that can transfer heat, because it has relatively fast response characteristics among thermal devices. To transmit thermal sensation, temperature control is considered to be important. However, it is difficult to design a controller because of factors such as parameter variations, nonlinear characteristics of the device, and heat that flows from an external object. Furthermore, it is preferable that the tracking performance and disturbance suppression characteristics be designed independently. To address these factors, this paper proposes a heat disturbance observer, which is constructed by using the disturbance observer commonly used in the field of motion control. When the observer is used, the thermal system becomes robust to the above‐mentioned factors. In addition, it is possible to design the tracking performance independently of the disturbance suppression characteristics. The validity of the proposal is confirmed by experimental results. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 184(1): 66–74, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22282     

Variable Dynamic Threshold of Jerk Signal for Contact Detection in Industrial Robots without Force Sensor

This study proposes a variable dynamic threshold for a jerk signal for achieving contact detection in industrial robots. Sensorless force control is useful in applications in advanced industrial robots. The external torque of each joint is estimated accurately by using a disturbance observer and by inverse dynamics calculations. However, the phase lag of the disturbance observer and the dynamic parameter error create force estimation errors. These errors hamper quick and reliable contact detection in industrial robots. Therefore, this study proposes a useful approach to contact detection that uses a variable dynamic threshold for a jerk signal. The proposed variable dynamic threshold reduces contact detection failures caused by force estimation errors during the free motion of a robot. The proposed threshold is suitable for robot motion and improves the speed of contact detection. Numerical simulation results show that the proposed method is valid for the parameter variations in an actual industrial robot. In addition, experimental results show that the dynamic threshold is a useful technique for application to general robot systems as well. The dynamic threshold is useful in applications for any industrial sensorless force control system.     

A literature review: robots in medicine

Robotic systems employed in the laboratory, in rehabilitation, and in surgery are reviewed. The advantages of using a robot system over manual procedures in the laboratory to prepare samples is discussed, and some of the obstacles are noted. A typical laboratory robot is described. Rehabilitative applications in the major research areas of tactile sensors, assistive devices for the blind, prosthetics, and orthotics are examined. Manipulators that can help a disabled individual with important everyday tasks and other assistive robotic systems in rehabilitation are described. A variety of robots that assist or perform surgery is surveyed. These applications include positioning in stereotactic neurosurgery, patient manipulation, an in vivo spinal kinematic instrument, and robotic radial keratotomy, among others.     

一种基于功放幅频特性的信号源设计方法

As unmanned electric wheeled mobile robots have been increasingly applied to high-speed operations in unknown environments, the wheel slip becomes a problem when the robot is either accelerating, decelerating, or turning at high speed. Ignoring the effect of wheel slip may cause the mobile robot to deviate from the desired path. In this paper a recently proposed method is implemented to estimate the surface conditions encountered by an unmanned wheeled mobile robot, without using extra sensors. The method is simple, economical and needs less processing power than for other methods. A reaction torque observer is used to obtain the rolling resistance torque and it is applied to a wheeled mobile robot to obtain the surface condition in real-time for each wheel. The slip information is observed by comparing the reaction torque of each wheel. The obtained slip information is then used to control the torque of both wheels using a torque controller. Wheel slip is minimized by controlling the torque of each wheel. Minimizing the slip improves the ability of the unmanned electric wheeled mobile robot to navigate in the desired path in an unknown environment, regardless of the nature of the surface.     

Control using joint torque sensor of robot arm with two‐inertia resonance: Comparison with control using state‐estimation observer

Most industrial robots are driven through reduction gears such as Harmonic Drives and RV gears. Due to the flexibility of the drive system, vibratory behavior occurs during operation. When flexibility is considered, the drive system of the robot joint can be modeled as a resonant mechanical system called a two‐inertia system. Conventionally, studies of two‐inertia system have discussed semiclosed‐loop control using only motor information and a state observer. On the other hand, joint torque sensing of robots has been studied in the harmonic drives that are widely used in robot joints. The joint torque sensor is becoming available with higher performance. In this paper, we consider the control of a robot arm having two‐inertia resonance by using the joint torque sensor. The performance of the torque sensor and that of the observer are compared. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 156(2): 75–84, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20226     

Integrated reproduction of human motion components by motion copying system

Currently, the development of leading‐edge technology for recording and loading human motion on the basis of haptic information is required in the fields of manufacturing and human support. Human movement is an assembly of motion components. Since human movements should be supported by a robot in real time, it is necessary to integrate the motion components that were saved earlier. Once such motion integration is realized, future technology for use in daily human life can be developed. This paper proposes the integrated reproduction of the decomposed components of human motion by using a motion copying system. This system is the key technology for the realization of the acquisition, saving, and reproduction of real‐world haptic information. By using the proposed method, it is possible not only to achieve expert skill acquisition, skill transfer to robots, and power assist for each motion component, but also to open up new areas of applications. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 181(1): 28–35, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21263     

Tracking control for industrial robot using notch filtering system with little phase error

This paper proposes a new method for generation of a position reference that has both vibration suppression performance and fast tracking performance for industrial robots. It is important for industrial robots to drive at high speed and with high accuracy. In such cases, vibration is generated. Conventionally, the notch filter is used in order to reduce vibration. It is able to eliminate the natural frequency component, but a reference phase error is generated. The reference phase error causes locus error in the robot. Therefore, the accuracy of the robot is degraded by using a notch filter. The proposed method overcomes this problem by using the compensation gain. The proposed compensation gain is used in order to calculate the reference phase error. Compensation of the reference phase error is attained by feedforward input. Numerical and the experimental results confirm that the proposed method is valid for reducing vibration phenomena and that it decreases the phase error. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 175(1): 53–63, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.20931     

Autonomous Variable‐Resolution Map Building for Mobile Robots in Unknown Environments

This paper presents a method that allows simultaneous map building and path planning for mobile robots in unknown environments. A graphical representation of a workspace in variable resolutions is constructed using measurement data obtained by omnidirectional distance sensors. At the same time, a search for a feasible path to the target destination is executed using the constructed graph map. The proposed method is evaluated by performing simulations and experiments using an omnidirectional mobile robot equipped with laser range finders. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 186(4): 59–69, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22493     

Multi‐target detection and grasping control for humanoid robot NAO

Graspirng objects is an important capability for humanoid robots. Due to complexity of environmental and diversity of objects, it is difficult for the robot to accurately recognize and grasp multiple objects. In response to this problem, we propose a robotic grasping method that uses the deep learning method You Only Look Once v3 for multi‐target detection and the auxiliary signs to obtain target location. The method can control the movement of the robot and plan the grasping trajectory based on visual feedback information. It is verified by experiments that this method can make the humanoid robot NAO grasp the object effectively, and the success rate of grasping can reach 80% in the experimental environment.     

A control method based on modal transformation for biped robots to climb unknown steps

This paper proposes a control method based on a modal transformation for biped robots to climb unknown steps. The method is able to control the foot position of the biped robot and the ground reaction force acting in the vertical direction when the biped robot climbs unknown steps in a double support phase. The effectiveness of the proposed method is confirmed by the results of simulations and experiments. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 181(3): 59‐69, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21265     

Position Control of a Wheeled Mobile Robot Including Tire Behavior

Advanced driver assistance systems are increasingly available on road vehicles. These systems require a thorough development procedure, an important part of which consists of hardware-in-the-loop experiments in a controlled environment. To this end, a facility called vehicle hardware-in-the-loop (VeHIL) is operated, aiming at testing the entire road vehicle in an artificial environment. In VeHIL, the test vehicle is placed on a roller bench, whereas other traffic participants, i.e., vehicles in the direct neighborhood of the test vehicle, are simulated using wheeled mobile robots (WMRs). To achieve a high degree of experiment reproducibility, focus is put on the design of an accurate position control system for the robots. Due to the required types of maneuvers, these robots have independently driven and steered wheels. Consequently, the robot is overactuated. Furthermore, since the robot is capable of high-dynamic maneuvers, slip effects caused by the tires can play an important role. A position controller based on feedback linearization is presented, using the so-called multicycle approach, which regards the robot as a set of identical unicycles. As a result, the WMR is position controlled, whereas each unicycle is controlled, taking weight transfer and longitudinal and lateral tire slip into account.     

基于改进 SSI 法的加工机器人工作模态在线辨识

为提高串联式机器人的加工能力,提出一种基于改进SSI 法的加工机器人工作模态在线辨识方法,该方法首先在传统 SSI法的基础上进行改进,利用NExT 法、模态置信因子及模态保证准则3种手段来提高加工机器人工作模态参数辨识精度。 其次,利用加工机器人铣削加工振动数据对其走刀路径上关键点位出的模态频率和阻尼比进行在线辨识。最终,通过机器人 切削加工实验验证该方法,实验结果表明,相比于锤击实验结果,改进 SSI 法模态参数辨识误差在7%以内,且相比于传统 SSI 法,改进 SSI 法模态参数辨识精度更高。因此,若仅关心模态频率及阻尼比,该方法可实现加工机器人走刀过程中模态参数的 在线辨识,可为后续机器人进行工艺规划和优化提供输入条件。     

Task learning of a task robot in real space by using a learning system in virtual space

Reinforced learning by which a robot acquires control rules by trial and error has attracted considerable attention. However, it is quite difficult for robots to acquire control rules by reinforcement learning in the real space because many learning trials are needed to arrive at the control rules; the robot itself may lose control, or there may be safety problems with the control objects. In this paper we propose a method in which a robot in the real space learns a virtual task, after which the task is transferred from the virtual to the real space. The robot eventually acquires the task in a real environment. We show that a real robot can acquire a task in a virtual space with an input device, using the example of an inverted pendulum. Next, we verify that the acquired task in the virtual space can be applied to a real‐world task. We emphasize the utilization of the virtual space to effectively obtain the real‐world task. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 172(1): 38–47, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20968     

融合行人运动信息的室内移动机器人动态避障方法

为了提高移动机器人在室内人机共融环境下的运动安全和交互性,提出了一种融合行人运动信息的室内移动机器人动 态避障方法,同时考虑任务约束和社会规则。 首先,利用 YOLO v3 算法和 Deep Sort 算法分别对室内环境中的行人进行实时检 测与目标跟踪,计算行人在过去时刻的历史轨迹。 然后,利用 Social-GAN 算法构建行人交互模型,实现轨迹预测。 在此基础上, 将行人的运动状态融合进机器人避障算法之中,根据社会规则设计评价函数,对机器人采样速度样本进行评估,使移动机器人 能够以安全和舒适的方式绕过行人,确保室内人机共融环境下移动机器人的社会接受性。 通过实验对比分析,与传统 DWA 方 法相比,本文方法不仅可以提高机器人导航避障效率,在相同室内场景下导航避障时间由 23. 56 s 提高到 19. 38 s,而且可以有 效降低与行人发生碰撞的风险,保证机器人导航的安全和社交性。     

Movement Control of Accompanying Robot Based on Artificial Potential Field Adapted to Dynamic Environments

This paper focuses on mobile robots that can accompany a person, that is, it addresses how to control the position of the robot relative to the accompanied person according to the dynamic environment. The robot is expected to move side by side with the person in a normal situation, but a position in front or behind the person might be better if there are obstacles. The shape of the artificial potential field of the accompanied person is devised to smoothly control the robot position in a unified way. The Laplace potential method is also used subsidiarily to cope with extremely cluttered environments. Simulations and experiments in real space show the usefulness of the proposed method.