외란 및 토크 대역폭 제한을 고려한 토크 기반의 작업 공간 제어

학위논문(박사) -- 서울대학교대학원 : 융합과학기술대학원 융합과학부(지능형융합시스템전공), 2021.8. 박재흥.The thesis aims to improve the control performance of the torque-based operational space controller under disturbance and torque bandwidth limitation. Torque-based robot controllers command the desired torque as an input signal to the actuator. Since the torque is at force-level, the torque-controlled robot is more compliant to external forces from the environment or people than the position-controlled robot. Therefore, it can be used effectively for the tasks involving contact such as legged locomotion or human-robot interaction. Operational space control strengthens this advantage for redundant robots due to the inherent compliance in the null space of given tasks. However, high-level torque-based controllers have not been widely used for transitional robots such as industrial manipulators due to the low performance of precise control. One of the reasons is the uncertainty or disturbance in the kinematic and dynamic properties of the robot model. It leads to the inaccurate computation of the desired torque, deteriorating the control stability and performance. To estimate and compensate the disturbance using only proprioceptive sensors, the disturbance observer has been developed using inverse dynamics. It requires the joint acceleration information, which is noisy due to the numerical error in the second-order derivative of the joint position. In this work, a contact-consistent disturbance observer for a floating-base robot is proposed. The method uses the fixed contact position of the supporting foot as the kinematic constraints to estimate the joint acceleration error. It is incorporated into the dynamics model to reduce its effect on the disturbance torque solution, by which the observer becomes less dependent on the low-pass filter design. Another reason for the low performance of precise control is torque bandwidth limitation. Torque bandwidth is determined by the relationship between the input torque commanded to the actuator and the torque actually transmitted into the link. It can be regulated by various factors such as inner torque feedback loop, actuator dynamics, and joint elasticity, which deteriorates the control stability and performance. Operational space control is especially prone to this problem, since the limited bandwidth of a single actuator can reduce the performance of all related tasks simultaneously. In this work, an intuitive way to penalize low performance actuators is proposed for the operational space controller. The basic concept is to add joint torques only to high performance actuators recursively, which has the physical meaning of the joint-weighted torque solution considering each actuator performance. By penalizing the low performance actuators, the torque transmission error is reduced and the task performance is significantly improved. In addition, the joint trajectory is not required, which allows compliance in redundancy. The results of the thesis were verified by experiments using the 12-DOF biped robot DYROS-RED and the 7-DOF robot manipulator Franka Emika Panda.본 학위 논문은 외란과 토크 대역폭 제한이 존재할 때 토크 기반 작업 공간 제어기의 제어 성능을 높이는 것을 목표로 한다. 토크 기반의 로봇 제어기는 목표 토크를 입력 신호로서 구동기에 전달한다. 토크는 힘 레벨이기 때문에, 토크 제어 로봇은 위치 제어 로봇에 비해 외부 환경이나 사람으로부터 가해지는 외력에 더 유연하게 대응할 수 있다. 그러므로 토크 제어는 보행이나 인간-로봇 상호작용과 같은 접촉을 포함하는 작업을 위해 효과적으로 사용될 수 있다. 작업 공간 제어는 이러한 토크 제어의 장점을 더 강화시킬 수 있는데, 로봇이 여유 자유도가 있을 때 작업의 영공간에서 존재하는 모션들이 내재적으로 유연하기 때문이다. 그러나 이러한 장점에도 불구하고 토크 기반의 로봇 제어기는 정밀 제어 성능이 떨어지기 때문에 산업용 로봇 팔과 같은 전통적인 로봇에는 널리 사용되지 못했다. 그 이유 중 한 가지는 로봇 모델의 기구학 및 동역학 물성치에 존재하는 외란이다. 모델 오차는 목표 토크를 계산할 때 오차를 유발하며, 이것이 제어 안정성과 성능을 약화시키게 된다. 외란을 내재 센서만을 이용하여 추정 및 보상하기 위해 역동역학 기반의 외란 관측기가 개발되어 왔다. 외란 관측기는 역동역학 계산을 위해 관절 각가속도 정보가 필요한데, 이 값이 관절 위치를 두 번 미분한 값이기 때문에 수치적인 오차로 노이즈해지는 문제가 있었다. 본 연구에서는 부유형 기저 로봇을 위한 접촉 조건이 고려된 외란 관측기가 제안되었다. 제안된 방법은 로봇의 고정된 접촉 지점에 대한 기구학적인 구속 조건을 이용하여 관절 각가속도 오차를 추정한다. 추정된 오차를 동역학 모델에 반영하여 외란 토크를 계산함으로써 저역 통과 필터 성능에 대한 의존도를 줄일 수 있다. 토크 기반 제어의 정밀 제어 성능이 떨어지는 또 다른 이유 중 하나는 토크 대역폭 제한이다. 토크 대역폭은 구동기에 전달되는 입력 토크와 실제 링크에 전달되는 토크와의 관계로 결정된다. 토크 대역폭은 구동기 내부의 토크 피드백 루프, 구동기 동역학, 관절 탄성 등의 요인들에 의해 제한될 수 있는데 이것이 제어 안정성 및 성능을 감소시킨다. 작업 공간 제어는 특히 이 문제에 취약한데, 대역폭이 제한된 구동기 하나가 그와 연관된 모든 작업 공간의 제어 성능을 감소시킬 수 있기 때문이다. 본 연구에서는 작업 공간 제어기에서 성능이 낮은 구동기의 사용을 제한하기 위한 직관적인 전략이 제안되었다. 기본 컨셉은 작업 제어를 위한 토크 솔루션에 성능이 좋은 관절에만 추가적으로 토크 솔루션을 더해나가는 것으로, 이것은 각 관절의 가중치가 고려된 토크 솔루션이 되는 것을 의미한다. 성능이 낮은 구동기의 사용을 제한함으로써 토크 전달 오차가 줄어들고 작업 성능이 크게 향상될 수 있다. 본 학위 논문의 연구 결과들은 12자유도 이족 보행 로봇 DYROS-RED와 7자유도 로봇 팔 Franka Emika Panda를 이용한 실험을 통해 검증되었다.1 INTRODUCTION 1 1.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Contributions of Thesis . . . . . . . . . . . . . . . . . . . . . . . 4 1.3 Overview of Thesis . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2 BACKGROUNDS 6 2.1 Operational Space Control . . . . . . . . . . . . . . . . . . . . . . 6 2.2 Dynamics Formulation . . . . . . . . . . . . . . . . . . . . . . . . 9 2.2.1 Fixed-Base Dynamics . . . . . . . . . . . . . . . . . . . . 9 2.2.1.1 Joint Space Formulation . . . . . . . . . . . . . 9 2.2.1.2 Operational Space Formulation . . . . . . . . . . 11 2.2.2 Floating-Base Dynamics . . . . . . . . . . . . . . . . . . . 12 2.2.2.1 Joint Space Formulation . . . . . . . . . . . . . 12 2.2.2.2 Operational Space Formulation . . . . . . . . . . 14 2.3 Position Tracking via PD Control . . . . . . . . . . . . . . . . . . 17 2.3.1 Torque Solution . . . . . . . . . . . . . . . . . . . . . . . 17 2.3.2 Orientation Control . . . . . . . . . . . . . . . . . . . . . 19 3 CONTACT-CONSISTENT DISTURBANCE OBSERVER FOR FLOATING-BASE ROBOTS 22 3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 3.2 Momentum-Based Disturbance Observer . . . . . . . . . . . . . . 24 3.3 The Proposed Method . . . . . . . . . . . . . . . . . . . . . . . . 25 3.4 Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 3.4.1 Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 3.4.2 External Force Estimation . . . . . . . . . . . . . . . . . . 33 3.4.3 Internal Disturbance Rejection . . . . . . . . . . . . . . . 35 3.5 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 4 OPERATIONAL SPACE CONTROL UNDER ACTUATOR BANDWIDTH LIMITATION 40 4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 4.2 The Proposed Method . . . . . . . . . . . . . . . . . . . . . . . . 43 4.2.1 General Concepts . . . . . . . . . . . . . . . . . . . . . . . 43 4.2.2 OSF-Based Torque Solution . . . . . . . . . . . . . . . . . 45 4.2.3 Comparison With a Typical Method . . . . . . . . . . . . 47 4.3 Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 4.3.1 Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 4.3.2 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 4.4 Comparison With Other Approaches . . . . . . . . . . . . . . . . 61 4.4.1 Controller Formulation . . . . . . . . . . . . . . . . . . . . 62 4.4.1.1 The Proposed Method . . . . . . . . . . . . . . . 62 4.4.1.2 The OSF Controller . . . . . . . . . . . . . . . . 62 4.4.1.3 The OSF-Filter Controller . . . . . . . . . . . . 62 4.4.1.4 The OSF-Joint Controller . . . . . . . . . . . . . 67 4.4.1.5 The Joint Controller . . . . . . . . . . . . . . . . 68 4.4.2 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 4.5 Frequency Response of Joint Torque . . . . . . . . . . . . . . . . 72 4.6 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 5 CONCLUSION 85 Abstract (In Korean) 100박

Design and Control of an Anthropomorphic Robotic Finger with Multi-point Tactile Sensation

The goal of this research is to develop the prototype of a tactile sensing platform for anthropomorphic manipulation research. We investigate this problem through the fabrication and simple control of a planar 2-DOF robotic finger inspired by anatomic consistency, self-containment, and adaptability. The robot is equipped with a tactile sensor array based on optical transducer technology whereby localized changes in light intensity within an illuminated foam substrate correspond to the distribution and magnitude of forces applied to the sensor surface plane. The integration of tactile perception is a key component in realizing robotic systems which organically interact with the world. Such natural behavior is characterized by compliant performance that can initiate internal, and respond to external, force application in a dynamic environment. However, most of the current manipulators that support some form of haptic feedback either solely derive proprioceptive sensation or only limit tactile sensors to the mechanical fingertips. These constraints are due to the technological challenges involved in high resolution, multi-point tactile perception. In this work, however, we take the opposite approach, emphasizing the role of full-finger tactile feedback in the refinement of manual capabilities. To this end, we propose and implement a control framework for sensorimotor coordination analogous to infant-level grasping and fixturing reflexes. This thesis details the mechanisms used to achieve these sensory, actuation, and control objectives, along with the design philosophies and biological influences behind them. The results of behavioral experiments with a simple tactilely-modulated control scheme are also described. The hope is to integrate the modular finger into an %engineered analog of the human hand with a complete haptic system

Anthropomorphic robot finger with multi-point tactile sensation

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2001.Includes bibliographical references (p. 84-95).The goal of this research is to develop the prototype of a tactile sensing platform for anthropomorphic manipulation research. We investigate this problem through the fabrication and simple control of a planar 2-DOF robotic finger inspired by anatomic consistency, self-containment, and adaptability. The robot is equipped with a tactile sensor array based on optical transducer technology whereby localized changes in light intensity within an illuminated foam substrate correspond to the distribution and magnitude of forces applied to the sensor surface plane [58]. The integration of tactile perception is a key component in realizing robotic systems which organically interact with the world. Such natural behavior is characterized by compliant performance that can initiate internal, and respond to external, force application in a dynamic environment. However, most of the current manipulators that support some form of haptic feedback, either solely derive proprioceptive sensation or only limit tactile sensors to the mechanical fingertips. These constraints are due to the technological challenges involved in high resolution, multi-point tactile perception. In this work, however, we take the opposite approach, emphasizing the role of full-finger tactile feedback in the refinement of manual capabilities. To this end, we propose and implement a control framework for sensorimotor coordination analogous to infant-level grasping and fixturing reflexes. This thesis details the mechanisms used to achieve these sensory, actuation, and control objectives, along with the design philosophies and biological influences behind them. The results of behavioral experiments with the tactilely-modulated control scheme are also described. The hope is to integrate the modular finger into an engineered analog of the human hand with a complete haptic system.by Jessica Lauren Banks.S.M

Bio-Inspired Robotics

Modern robotic technologies have enabled robots to operate in a variety of unstructured and dynamically-changing environments, in addition to traditional structured environments. Robots have, thus, become an important element in our everyday lives. One key approach to develop such intelligent and autonomous robots is to draw inspiration from biological systems. Biological structure, mechanisms, and underlying principles have the potential to provide new ideas to support the improvement of conventional robotic designs and control. Such biological principles usually originate from animal or even plant models, for robots, which can sense, think, walk, swim, crawl, jump or even fly. Thus, it is believed that these bio-inspired methods are becoming increasingly important in the face of complex applications. Bio-inspired robotics is leading to the study of innovative structures and computing with sensory–motor coordination and learning to achieve intelligence, flexibility, stability, and adaptation for emergent robotic applications, such as manipulation, learning, and control. This Special Issue invites original papers of innovative ideas and concepts, new discoveries and improvements, and novel applications and business models relevant to the selected topics of ``Bio-Inspired Robotics''. Bio-Inspired Robotics is a broad topic and an ongoing expanding field. This Special Issue collates 30 papers that address some of the important challenges and opportunities in this broad and expanding field

Unified Motion Planner for Walking, Running, and Jumping Using the Three-Dimensional Divergent Component of Motion

Running and jumping are locomotion modes that allow legged robots to rapidly traverse great distances and overcome difficult terrain. In this article, we show that the 3-D divergent component of motion (3D-DCM) framework, which was successfully used for generating walking trajectories in previous works, retains its validity and coherence during flight phases, and, therefore, can be used for planning running and jumping motions. We propose a highly efficient motion planner that generates stable center-of-mass (CoM) trajectories for running and jumping with arbitrary contact sequences and time parametrizations. The proposed planner constructs the complete motion plan as a sequence of motion phases that can be of different types: stance, flight, transition phases, etc. We introduce a unified formulation of the CoM and DCM waypoints at the start and end of each motion phase, which makes the framework extensible and enables the efficient waypoint computation in matrix and algorithmic form. The feasibility of the generated reference trajectories is demonstrated by extensive whole-body simulations with the humanoid robot TORO

Hierarchical neural control of human postural balance and bipedal walking in sagittal plane

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 177-192).The cerebrocerebellar system has been known to be a central part in human motion control and execution. However, engineering descriptions of the system, especially in relation to lower body motion, have been very limited. This thesis proposes an integrated hierarchical neural model of sagittal planar human postural balance and biped walking to 1) investigate an explicit mechanism of the cerebrocerebellar and other related neural systems, 2) explain the principles of human postural balancing and biped walking control in terms of the central nervous systems, and 3) provide a biologically inspired framework for the design of humanoid or other biomorphic robot locomotion. The modeling was designed to confirm neurophysiological plausibility and achieve practical simplicity as well. The combination of scheduled long-loop proprioceptive and force feedback represents the cerebrocerebellar system to implement postural balance strategies despite the presence of signal transmission delays and phase lags. The model demonstrates that the postural control can be substantially linear within regions of the kinematic state-space with switching driven by sensed variables.(cont.) A improved and simplified version of the cerebrocerebellar system is combined with the spinal pattern generation to account for human nominal walking and various robustness tasks. The synergy organization of the spinal pattern generation simplifies control of joint actuation. The substantial decoupling of the various neural circuits facilitates generation of modulated behaviors. This thesis suggests that kinematic control with no explicit internal model of body dynamics may be sufficient for those lower body motion tasks and play a common role in postural balance and walking. All simulated performances are evaluated with respect to actual observations of kinematics, electromyogram, etc.by Sungho JoPh.D

Innovative technologies for the actuation of space manipulators

In this work, innovative technologies for the actuation of space robotic systems are investigated as possible alternative to traditional motors. The research activity focused on double-cone Dielectric Elastomer Actuators (DEAs). The most notable results achieved are predictive models for the static and dynamic performances estimation of the mentioned devices and experimental validation of both single actuators and a robotic arm prototype. The general objective of the thesis is to evaluate innovative actuation technologies for space robotics; the main expected output of the research is the feasibility proof of a robotic space system based on low-TRL (Technology Readiness Level) devices. This objective is achieved by fulfilling two secondary goals: - development of models to predict the actuator performances and validation of ready-to-use design tools; - experimental evaluation of a multi-body manipulator prototype in laboratory environment. The motivation on which this work is based, comes from the wide interest on robotics that recently grew among the space community. A large variety of space missions can benefit from the implementation of automated systems reducing risks, costs, delays and errors deriving from human interaction (i.e. astronauts or ground operators) with space vehicles and structures. On-Orbit Servicing (OOS) missions, in particular, are based on robotic servicing vehicles that perform complex tasks on client objects enabling unprecedented scenarios of improved accessibility to space. Future effective and efficient exploitation of space is strongly dependent on the development of key technologies to support existing and planned orbital assets, aiming to extend spacecraft operational life and to boost mission flexibility. Investigation on innovative actuation technologies is critical to improve space robotics performances and enable new applications. The TRL advancement of young technologies is at the basis of the development of new systems. To date, a considerable number of relevant applications of robotics have been operated in space; main tasks include assembly of complex structures, manipulation of client vehicles and support to astronauts activities. Five human operated manipulators have equipped the Space Shuttle or the International Space Station (ISS), along with a variety of other experimental demonstrators; three examples of humanoid robotic astronauts have been tested and reached different levels of development; a wide range of autonomous demonstrative OOS missions have been conceived and designed, are currently under development or, in some cases, have been flown with success; several planetary probes and (partially) autonomous rovers have been operated on the surface of extraterrestrial bodies like the Moon or Mars. These missions and others constitute the solid background on which this work is based and consolidate the motivation behind the research. The past and present trend in the space sector is to seek improved capabilities, flexibility and autonomy of vehicles, assigning a prominent role to robotics as a key enabling technology. By far the most common actuators in space systems are conventional DC drives like stepper motors and brushless motors: the first are used in robotic arms for control simplicity and positioning accuracy, the second are the standard option in reaction wheels. In some cases brushed DC motors (in sealed or planetary environment) and, less often, voice coil motors have been used. Innovative technologies, like smart materials, are rarely adopted mainly due to reliability and heritage reasons. In general, the space community is very conservative and new technologies have to be proven fail safe and robust, and, for this reason, well-known solutions are often preferred. Nevertheless, implementation examples of smart technologies in space exist and they performed particularly well in off-nominal conditions, where traditional solutions show limitations. It is worth mentioning the most notable: piezo-electric actuators and motors, used in micro-positioning and precision pointing; shape memory devices, employed in release mechanisms; bimetallic actuators, implemented in single-shot systems and thermal control; Electro-Active Polymers (EAPs). The latter have not been extensively employed in space systems yet, although interest is growing around them on the basis of the appealing capabilities proved in many laboratory tests. A wide choice of alternative EAP materials and configurations have been proposed, with ample performance ranges. Dielectric Elastomer Actuators are a promising branch of EAPs family, whose space TRL is currently 2-3. Dielectric Elastomers are arguably the best performing EAPs and, for this reason, very appealing. DEAs have been selected to be investigated in this work for three main reasons: - good compromise performances in terms of stroke/deformation, force/torque and time response; - interesting characteristics like low mass and low power consumption, possibility to improve performances through design flexibility and modularity, multi-DoF configurations, simple manufacturing process, low costs, solid state actuation (no friction), self-sensing capability; - highly innovative technology with low TRL. Double-cone actuators are selected for their flexibility and multi-DoF architecture. An example mission scenario is conceived and simulated in order to determine preliminary requirements for the robotic system and the single actuator. An Active Debris Removal (ADR) mission is selected as a key OOS application of robotic systems. In the considered scenario a large piece of debris (1400 kg) is captured by a small spacecraft by means of a multi-DoF manipulator. The debris is spinning with respect to the servicing spacecraft which is equipped with a robotic arm composed by a variable number of joints (1-3). The capture interface is rigid and guarantees the mechanical connection between the manipulator and the client object. Several simulations are performed with different initial conditions and capture strategies, including the options of a rigidly controlled or free flying spacecraft. The requirements have been defined in terms of forces/torques and rotations at the robot joints. The maximum angular deflection required to the entire robotic arm is 90 deg; torque and forces are strongly dependent on the initial debris (relative) angular momentum, thus it is possible to relax the joint requirement imposing stricter constraints to the target selection or relative navigation system of the servicer. The double-cone DE actuator is based on two circular, pre-stretched membranes of elastomer coated with compliant electrodes on both sides. By applying high voltage to the electrodes, electrostatic forces squeeze the membrane reducing its thickness and, consequently, expanding the material in the plane. Such material deformation is exploited to displace the actuator shaft. Multiple DoF are obtained by selecting a proper electrode layout; a 2-DoF (one rotational and one translational) configuration is selected in view of the proposed robotic application. On the basis of the results available in literature, the commercial polyacrylic elastomer called 3M VHB 49XX is chosen. Proper electromechanical models are identified for the mentioned polymer. Once a set of geometrical and manufacturing parameters are defined, numerical simulations based on literature as well as newly developed FEM models are performed in order to collect a large number of performance data. Interpolating relations are obtained from the collected data and allow to estimate the steady-state performances of the actuator. Torque/force and rotation/stroke are proportional to the squared value of applied high-voltage. The mentioned relations allow to compute the gain to which squared voltage has to be multiplied to estimate the desired quantity. The mean error on estimations is 6.1% for angular rotation, 10.6% for torque, 22.5% for linear stroke and 11.8% for force. A different approach is adopted to model the dynamic behavior of DEAs: transfer function (TF) based models are developed from time dependent data collected through long term tests. The elastomeric material adopted in the device manufacturing shows a relevant viscoelastic behavior that considerably affects the time response of actuators. The TF approach is chosen to simplify the estimation of the transient behavior of DEAs and to provide a practical design tool for robotic applications. The prediction capabilities of TF models are evaluated by comparison with experimental step response. The mean error on the 70% rise time is 15% for angular rotation, 9.5% for torque, 14% for linear stroke and 14% for force; the mean error on amplitude for t > t_r is 4% for angular rotation, 4% for torque, 9% for linear stroke and 11% for force. The developed models, both static and dynamic, are suitable for the implementation of control algorithms and, consequently, for robotic applications. The capability to control the actuator is experimentally proven by testing Single Input / Single Output compensators to actuate both DoF independently. Laboratory tests are conducted in order to evaluate the step response of double-cone actuators. Good accordance is obtained between the simulated and the experimentally measured time response with errors compatible with the prediction inaccuracies of the mentioned models. Finally, a multi-body application of double-cone actuators is designed, manufactured and tested along with a proper control algorithm. The robotic arm is composed by two double-cone DEAs mounted in series. Each actuator has two DoFs and the manipulator moves in the horizontal plane. Two degrees of kinematic redundancy are achieved in the manipulator by controlling only the in-plane position of the end-effector. The arm prototype is suspended by an inextensible cable that reduces the effects of gravity on the motion. The experimental task is the tracking of simple linear and arc trajectories. A vision system monitors the position of the end-effector (optical marker) and feeds the position information to a control computer that commands the voltage actuation to the joints through a properly designed control algorithm. The kinematic redundancy is exploited by the controller to optimize the end-effector trajectory to achieve a given objective: several control schemes with alternative optimization functions are designed and simulated numerically in order to select the best performing option. The chosen control algorithm aims at the minimization of joint variables in order to reduce the risk of actuators saturation. The system performs well and the maximum position error norm is 6.4% of total path length for linear trajectory and 6.8% for arc trajectory

Robotics 2010

Without a doubt, robotics has made an incredible progress over the last decades. The vision of developing, designing and creating technical systems that help humans to achieve hard and complex tasks, has intelligently led to an incredible variety of solutions. There are barely technical fields that could exhibit more interdisciplinary interconnections like robotics. This fact is generated by highly complex challenges imposed by robotic systems, especially the requirement on intelligent and autonomous operation. This book tries to give an insight into the evolutionary process that takes place in robotics. It provides articles covering a wide range of this exciting area. The progress of technical challenges and concepts may illuminate the relationship between developments that seem to be completely different at first sight. The robotics remains an exciting scientific and engineering field. The community looks optimistically ahead and also looks forward for the future challenges and new development

Robot Manipulators

Robot manipulators are developing more in the direction of industrial robots than of human workers. Recently, the applications of robot manipulators are spreading their focus, for example Da Vinci as a medical robot, ASIMO as a humanoid robot and so on. There are many research topics within the field of robot manipulators, e.g. motion planning, cooperation with a human, and fusion with external sensors like vision, haptic and force, etc. Moreover, these include both technical problems in the industry and theoretical problems in the academic fields. This book is a collection of papers presenting the latest research issues from around the world

Pedestrian accident simulation and protection technology evaluation

Pedestrian safety is an important societal issue and as one of the stakeholders, vehicle manufacturers are attempting to improve pedestrian protection by enhancing vehicle design. In order to enhance vehicle design, first it is necessary to gain an improved understanding of the interactions between a pedestrian and a vehicle during an accident. Secondly, this knowledge needs to be transformed into vehicle design and technology changes. This thesis focuses on the construction of new models and methodologies to provide an improved understanding and the application of this understanding to design, develop and evaluate a number of pedestrian protection technologies. A review of the pedestrian safety issue and different approaches to pedestrian protection research provide the background to the chosen approach. This is described in terms of an overall methodology for any pedestrian protection technology that also provides a framework for this research. The construction and evaluation of pedestrian accident simulations with a reference C class vehicle are described in detail. The influence of accident conditions and the expected ranges of various quantitative pedestrian injury and motion measures are identified. Vehicle impact velocity, pedestrian size and stance have significant influences on these measures. Therefore it is not possible to state, for instance, that under all accident conditions, one vehicle impact location is likely to cause lower injury measures than another is. There is a clear increase in pedestrian measures (e.g. head velocity, HIC, tibia acceleration, knee bending) with a large increase in impact velocity (i.e. 25 to 40 km/h). However, some measures (e.g. HIC) do not necessarily increase with a small increase in impact velocity (e.g. 25 to 30 km/h) because of the new pedestrian motion (e.g. a new head impact location). Large differences exist between the 6 year old pedestrian and adult pedestrian model measures (e.g. larger post head impact motion but smaller HIC and tibia acceleration) and pedestrian stance has a complex influence on all measures with few overall trends. Pedestrian protection headlamp, bumper system and hood system concepts are developed in biomechanical, analytical and numerical component models. These concepts are used to construct and subsequently benchmark, with pedestrian accident simulations, two modified vehicle models that incorporate different combinations of the technologies. Both the absolute measures and ranges of the measures from the reference vehicle simulations are compared. There are large differences between the pedestrian measures from the reference and modified vehicles but much smaller differences between the modified vehicles. Impacts with the modified vehicles cause the largest differences in pedestrian motion at 40 km/h, for the 6 year old pedestrian, in stance TV, in the early (up to 20 ms) and late (after 140 ms) stages of the accident simulations. Although the modified vehicles reduce pedestrian injury measures for some of the accident conditions, neither of them reduce all measures for all of the conditions. However, significant improvements in experimental sub system measures [EEVC 1998] are achieved with a prototype modified vehicle that incorporates some of the technologies. Benchmarking is hindered by complex injury measure trends and by pedestrian and vehicle model limitations. Recommendations are made with respect to all of these factors. Further recommendations include the need for optimisation of the modified vehicle technologies in accident simulations, a more complete investigation of other technology functional requirements (e.g. low speed damageability) and accident reconstruction as a means to achieve improved model validation.Ph