Showing papers in "Advanced Robotics in 2010"
TL;DR: The capacity of model predictive control to generate stable walking motions without the use of predefined footsteps is demonstrated and an online walking motion generator that can track a given reference speed of the robot and decide automatically the footstep placement is proposed.
Abstract: The goal of this paper is to demonstrate the capacity of Model Predictive Control to generate stable walking motions without the use of predefined foot steps. Building up on well-known Model Predictive Control schemes for walking motion generation, we show that a minimal modification of these schemes allows designing an online walking motion generator which can track a given reference speed of the robot and decide automatically the foot step placement. Simulation results are proposed on the HRP-2 humanoid robot, showing a significant improvement over previous approaches.
348 citations
TL;DR: The experimental results indicate that the proposed algorithms could support the sit-to-stand and stand- to-sit transfers of the complete paraplegic patient safely and conveniently by keeping his stability and by reflecting his intentions.
Abstract: Physical support of lower limbs during sit-to-stand and stand-to-sit transfers is important for an independent life of paraplegic patients. The purpose of this study is, therefore, to realize the control method of complete paraplegic patients during sit-to-stand and stand-to-sit transfers by using a 'robot suit HAL'. It is the most challenging issue because the HAL should start supporting the wearer's motions synchronizing his/her intention. Our proposed algorithm infers the intention based on a preliminary motion that is observed just before a desired motion so the patient could start the sit-to-stand or stand-to-sit transfers without any operation. When the HAL detects the intention to stand up and sit down, the HAL starts to support the wearer's weight and to control their body posture for stability during their transfer. The proposed algorithms embedded in the HAL were applied to a complete spinal cord injury patient in a clinical trial to confirm the effectiveness. The experimental results indicate t...
239 citations
TL;DR: The design and implementation of the HARK robot audition software system consisting of sound source localization modules, sound source separation modules and automatic speech recognition modules of separated speech signals that works on any robot with any microphone configuration are presented.
Abstract: This paper presents the design and implementation of the HARK robot audition software system consisting of sound source localization modules, sound source separation modules and automatic speech re...
209 citations
TL;DR: A distributed market-based algorithm, called S + T, has been developed to solve the multi-robot task allocation problem in applications that require cooperation among the robots to accomplish all the tasks.
Abstract: This paper presents a system for the coordination of aerial and ground robots for applications such as surveillance and intervention in emergency management. The overall system architecture is described. An important part for the coordination between robots is the task allocation strategy. A distributed market-based algorithm, called S + T, has been developed to solve the multi-robot task allocation problem in applications that require cooperation among the robots to accomplish all the tasks. Using this algorithm, robots can provide transport and communication relay services dynamically to other robots during the missions. Moreover, the paper presents a demonstration with a team of heterogeneous robots (aerial and ground) cooperating in a mission of fire detection and extinguishing.
85 citations
TL;DR: Simulation and experimental studies shown here demonstrate the validity of the approach and allow linear optimal control theory to be used to control the robots and minimize structural vibrations.
Abstract: The construction of future space structures in Earth orbit such as solar power stations and space telescopes will require coordinated teams of autonomous space robots. These robot teams can excite ...
76 citations
TL;DR: This paper describes a slave manipulator, which has 7 d.o.f. and is driven by pneumatic actuators, newly designed and developed for use in minimally invasive surgery and applies a different impedance control for each manipulator.
Abstract: In minimally invasive telesurgical systems, displaying the forces measured at the slave side is an important issue. The ability to accurately feel the force being applied at the slave side is impor...
58 citations
TL;DR: A high force artificial muscle of 40 mm in diameter that generates 28-kN contracting force has been developed successfully using ultra-high-strength p-phenylene-2,6-benzobisoxazole fiber sleeves to McKibben artificial muscles.
Abstract: Small and lightweight actuators that generate high force and high energy are strongly required for realizing powerful robots and tools. By applying ultra-high-strength p-phenylene-2,6-benzobisoxazole fiber sleeves to McKibben artificial muscles, new hydraulic artificial muscles have been developed. While conventional McKibben muscles are driven by a maximum pneumatic pressure of 0.7 MPa, the newly developed muscles are driven by a maximum water hydraulic of pressure of 4 MPa, resulting in very high force capability. This paper presents the materials and structure of the new artificial muscle and the experimental results. The developed muscles are evaluated by four parameters — force density per volume (FDV), force density per mass (FDM), energy density per volume (EDV) and energy density per mass (EDM) — for comparisons with other conventional linear actuators. The prototype artificial muscle, which is 40 mm in diameter and 700 mm in length, can achieve a maximum contracting force of 28 kN, FDV of 32.3 × ...
56 citations
TL;DR: This study has developed a compact magnetorheological fluid clutch (CMRFC) for human-friendly actuators and discusses experimental results on the basic characteristics of these devices.
Abstract: (2011). Development of a Compact Magnetorheological Fluid Clutch for Human-Friendly Actuator. Advanced Robotics: Vol. 25, No. 9-10, pp. 1362-1362.
55 citations
TL;DR: With the proposed direct teaching algorithm, the reference trajectory of a manipulator can be directly taught even when the manipulator comes into contact with the workpiece and the contact has to be maintained with small contact force while under the teaching process.
Abstract: This paper proposes a direct teaching algorithm to teach a manipulator in a constraint condition by the teaching force and moment of an operator. Most of the previous research supposes that an oper...
44 citations
TL;DR: A compensation method is proposed that realizes the desired energy consumption at a collision, which is represented by the coefficient of restitution in the hybrid simulation.
Abstract: A hybrid simulation, which is also referred to as a hardware-in-the-loop (HIL) simulation, includes a hardware experiment within a numerical simulation loop. The hybrid simulation is an effective method to test space robotic operations providing a virtual microgravity environment on the ground. However, hybrid simulation generally suffers from the problem of energy increase when two hardwares in the loop collide with each other because of delay times. This paper presents a compensation method for the energy increase problem. A dead time model that represents various delay times of the system is introduced and it is clarified how the energy of the system is increased by the dead time. Based upon the dead time model, a compensation for the dead time is proposed. This compensation method realizes the desired energy consumption at a collision, which is represented by the coefficient of restitution in the hybrid simulation. Experiments of uniaxial collision are conducted to validate the proposed compensation.
44 citations
TL;DR: This paper presents the vertical takeoff, landing and transition between level flight and hovering of a tail-sitter vertical takeoff and landing (VTOL) aerial robot, suitable for micro aerial vehicles because it does not need any extra equipment for the VTOL maneuver.
Abstract: This paper presents the vertical takeoff, landing and transition between level flight and hovering of a tail-sitter vertical takeoff and landing (VTOL) aerial robot. The tail-sitter is suitable for micro aerial vehicles because it does not need any extra equipment for the VTOL maneuver. The developed tail-sitter aerial robot is equipped with four actuators for controlling ailerons, an elevator, a rudder and a propeller. A micro computer, various sensors and a battery are mounted on the aerial robot for autonomous flight without any support from a ground system. A transition flight strategy is constructed so that the transition finishes in the shortest time restricting an altitude change. In order to achieve the transition strategy, the reference trajectory of the pitch angle is computed offline by using an optimization technique. In the transition flight control system, a PID feedback controller is applied to attitude control, while a feedforward controller is applied to altitude control. The gain schedul...
TL;DR: The problem of trajectory tracking control of an underactuated autonomous underwater robot (AUR) in a three-dimensional (3-D) space is investigated and the proposed hybrid control law is developed by combining sliding mode control and classical proportional–integral–derivative (PID) control methods to reduce the tracking errors arising out of disturbances.
Abstract: The problem of trajectory tracking control of an underactuated autonomous underwater robot (AUR) in a three-dimensional (3-D) space is investigated in this paper. The control of an underactuated robot is different from fully actuated robots in many aspects. In particular, these robot systems do not satisfy Brockett's necessary condition for feedback stabilization and no continuous time-invariant state feedback control law exists that makes a specified equilibrium of the closed-loop system asymptotically stable. The uncertainty of hydrodynamic parameters, along with the coupled, nonlinear dynamics of the underwater robot, also makes the navigation and tracking control a difficult task. The proposed hybrid control law is developed by combining sliding mode control (SMC) and classical proportional–integral–derivative (PID) control methods to reduce the tracking errors arising out of disturbances, as well as variations in vehicle parameters like buoyancy. Here, a trajectory planner computes the body-fixed lin...
TL;DR: A novel method based on visually observing the traces produced by the wheels of a robot on soft, deformable terrain to estimate the angle of inclination of the wheel trace with respect to the vehicle reference frame, based on an integrated longitudinal and lateral wheel–terrain slip model.
Abstract: This paper introduces a novel method for slip angle estimation based on visually observing the traces produced by the wheels of a robot on soft, deformable terrain. The proposed algorithm uses a robust Hough transform enhanced by fuzzy reasoning to estimate the angle of inclination of the wheel trace with respect to the vehicle reference frame. Any deviation of the wheel track from the planned path of the robot suggests occurrence of sideslip that can be detected and, more interestingly, measured. In turn, the knowledge of the slip angle allows encoder readings affected by wheel slip to be adjusted and the accuracy of the position estimation system to be improved, based on an integrated longitudinal and lateral wheel–terrain slip model. The description of the visual algorithm and the odometry correction method is presented, and a comprehensive set of experimental results is included to validate this approach.
TL;DR: The proposed adaptive control methods overcome two inherent difficulties in the adaptive control design of space robotic systems, such as nonlinear parameterization of the dynamic equation and uncertainties in coordinate mapping from Cartesian space to joint space.
Abstract: This paper proposes adaptive control methods based on reaction dynamics for different types of space robotic systems. Reaction dynamics feature the dynamic coupling between an actively operated part and a passively moving part in a multibody robotic system. The reaction dynamics have been used to develop trajectory tracking control of a free-floating space robot or vibration suppression control of a flexible-structure-based manipulator system. However, the presence of dynamic parameter uncertainties degrades the control performance of the above-mentioned methods, since the methods require accurate values of both kinematic and dynamic parameters. To resolve such parameter uncertainties, practical adaptive control methods are proposed in this study. The proposed methods overcome two inherent difficulties in the adaptive control design of space robotic systems, such as nonlinear parameterization of the dynamic equation and uncertainties in coordinate mapping from Cartesian space to joint space. To confirm th...
TL;DR: The findings demonstrate the feasibility of the prototype system to safely perform assembly operations and the design and development of a safety strategy for a human–robot collaboration system.
Abstract: Our research aims to design and develop a safety strategy for a human–robot collaboration system. Although robotic assistance in a cellular manufacturing system is promising, safety is the uppermost consideration before it can be materialized. Five main safety designs are developed in this work. (i) Safe working areas for humans and robots. (ii) To control the behavior of the robot based on the collaboration requirements, light curtains defined safe collaborative working zones. (iii) Additionally, the robot system was developed using safe mechanical design and Dual Check Safety control strategies in terms of robot speed and travel area to minimize collaboration risks. (iv) A vision system using IP cameras was developed to monitor operator safety conditions by measuring the body posture and position of the operator. (v) The operation control system coordinated the collaborative flow between the operator and robot system. Apart from these developments, risk assessments were conducted to evaluate the safety ...
TL;DR: A fast and robust method to fit planar surface patches into the data is presented and the usefulness of the approach is demonstrated in two different sets of experiments.
Abstract: Good situational awareness is an absolute must when operating mobile robots for planetary exploration. Three-dimensional (3-D) sensing and modeling data gathered by the robot are, hence, crucial for the operator. However, standard methods based on stereo vision have their limitations, especially in scenarios where there is no or only very limited visibility, e.g., due to extreme light conditions. Three-dimensional laser range finders (3-D-LRFs) provide an interesting alternative, especially as they can provide very accurate, high-resolution data at very high sampling rates. However, the more 3-D range data are acquired, the harder it becomes to transmit the data to the operator station. Here, a fast and robust method to fit planar surface patches into the data is presented. The usefulness of the approach is demonstrated in two different sets of experiments. The first set is based on data from our participation at the European Space Agency Lunar Robotics Challenge 2008. The second one is based on data from...
TL;DR: This study is a successful demonstration how expressive robot heads with rather technical design can benefit from additional expressive features, e.g., animal-like or fictionally designed, which are not based on FACS, in order to improve emotion expression.
Abstract: This paper investigates the influence of animal-like features (ears of a dragon lizard and comb of a cockatoo) and their pose variations on the quality of emotion expression of the robot head EDDIE. User studies are conducted presenting emotional expressions composed of the six basic emotions (based on Facial Action Coding Units (FACS) action units) in combination with the animal-like features under various inclination angles to human participants in randomized order. The results show that (i) the animal-like features have a significant influence on emotion expression, (ii) the expressed emotions are shifted in affective space dependent on the inclination angles of the animal-like features, (iii) these shifts are not uniform and differ in orientation for each of the expressed emotions, and (iv) for some emotions ground truth is matched better with the animal-like features in addition to FACS action units. The animal-like features, thus, help to improve the emotion expression of EDDIE, which is particularl...
TL;DR: An action planning algorithm is presented for a reconfigurable hybrid leg–wheel mobile robot that selects the appropriate locomotion mode along an optimal path toward a point of scientific interest for planetary exploration.
Abstract: In this paper, an action planning algorithm is presented for a reconfigurable hybrid leg–wheel mobile robot. Hybrid leg–wheel robots have recently receiving growing interest from the space community to explore planets, as they offer a solution to improve speed and mobility on uneven terrain. One critical issue connected with them is the study of an appropriate strategy to define when to use one over the other locomotion mode, depending on the soil properties and topology. Although this step is crucial to reach the full hybrid mechanism's potential, little attention has been devoted to this topic. Given an elevation map of the environment, we developed an action planner that selects the appropriate locomotion mode along an optimal path toward a point of scientific interest. This tool is helpful for the space mission team to decide the next move of the robot during the exploration. First, a candidate path is generated based on topology and specifications' criteria functions. Then, switching actions are defi...
TL;DR: This paper addresses the kinematics modeling and control of a novel nonholonomic wheel-based pole climbing robot called UT-PCR and it is shown that three orientations of the robot cannot be controlled independently.
Abstract: This paper addresses the kinematics modeling and control of a novel nonholonomic wheel-based pole climbing robot called UT-PCR. This robot belongs to a challenging and less-studied class of wheel-based mobile robots in which the relative position of the wheels changes in a complex manner and the robot is constrained to maneuver on a closed geometric surface. The problem is formulated in terms of the kinematic model of the robot, which is derived using non-holonomic constraints imposed by the wheels on the motion. This model is an underactuated driftless nonlinear state space (control system) which is linear in its inputs. Feasibility of complex maneuvering is then proved by an analysis of controllability for this nonlinear system. It is shown that three orientations of the robot cannot be controlled independently. Therefore, three basic movements are introduced as the fundamental elements of the kinematic control strategy and stable controllers are designed to create those basic movements. Simulation and ...
TL;DR: A leg-shaped robot (Leg-Robot) with a compact magnetorheological fluid clutch with a control method to demonstrate haptics of the ankle clonus is proposed and its effectiveness for learning of the test skill is confirmed.
Abstract: In this study, we propose a leg-shaped robot (Leg-Robot) with a compact magnetorheological fluid clutch to demonstrate several kinds of haptic control of abnormal movements of brain-injured patient...
Journal Article•
TL;DR: In this article, a fast and robust method to fit planar surface patches into the data is presented, based on a Velodyne 3D-LRF in a high fidelity simulation with ground truth data from Mars.
Abstract: Good situation awareness is an absolute must when operating mobile robots for planetary exploration. 3D sensing and modeling data gathered by the robot are hence crucial for the operator. But standard methods based on stereo vision have their limitations, especially in scenarios where there is no or only very limited visibility, e.g., due to extreme light conditions. 3D Laser Range Finders (3D-LRF) provide an interesting alternative, especially as they can provide very accurate, high resolution data at very high sampling rates. But the more 3D range data is acquired, the harder it becomes to transmit the data to the operator station. Here, a fast and robust method to fit planar surface patches into the data is presented. The usefulness of the approach is demonstrated in two different sets of experiments. The first set is based on data from our participation at the ESA Lunar Robotics Challenge 2008. The second one is based on data from a Velodyne 3D-LRF in a high fidelity simulation with ground truth data from Mars. keywords: space robotics, planetary exploration, 3D mapping, surface representation, plane fitting published in: Advanced Robotics, Vol. 24, Iss. 8-9, Brill, 2010
TL;DR: A novel two-stage approach to address the problem of multi-d.o.f. robot path planning in high-dimensional configuration space with narrow corridors that keeps a fine balance between global heuristics and local connection, resulting in high performance over the previous RRTs-based path planning methods.
Abstract: Although Rapidly-exploring Random Trees (RRTs) have been successfully applied in path planning of robots with many degrees of freedom under non-holonomic and differential constraints, rapidly identifying and passing through narrow passages in a robot's configuration space remains a challenge for RRTs-based planners. This paper presents a novel two-stage approach to address the problem of multi-d.o.f. robot path planning in high-dimensional configuration space with narrow corridors. The first stage introduces an efficient sampling algorithm called Bridge Test to find a global roadmap that identifies the critical region. The second stage presents two varieties of RRTs, called Triple-RRTs, to search for a local connection under the guidance of the global landmark. The two-stage strategy keeps a fine balance between global heuristics and local connection, resulting in high performance over the previous RRTs-based path planning methods. We have implemented the Triple-RRTs planners for both rigid and articulate...
TL;DR: An Intelligent Chair Tool is developed — a new chair-type human and machine interaction seating system powered by 36 intelligent pneumatic actuators that can be used to facilitate investigation of chair shapes from spring and damping effects of seating and backrest surfaces.
Abstract: This paper develops an Intelligent Chair Tool (ICT) - a new chair-type human and machine interaction seating system powered by 36 intelligent pneumatic actuators. This tool can be used to facilitate investigation of chair shapes from spring and damping effects of seating and backrest surfaces. Each actuator used consists of five extensive elements of encoder, laser strip rod, pressure sensor, valves and PSoC microcontroller incorporated in a single device. By using the ICT, different shapes, spring and damping characteristics can be obtained to aid the design of chairs from the control inputs, i.e., position x, stiffness k(s) and viscous coefficient c. Several control algorithms are presented to realize the communication and control system, and to obtain all data in real-time. The control methodology presented contains an inner force loop and an outer position loop implemented using a unified control system. The specification, development design and experimental evaluation of the ICT control system and actuator used are presented and discussed.
TL;DR: A framework for designing active and human-compliant navigation behaviors is proposed, in which a set of safety strategies is put forward to guarantee human physical safety and mental comfort and incorporate social conventions into robot navigational behaviors.
Abstract: The human-symbiotic service robot raises new safety issues for autonomous navigation in the presence of people. Traditional obstacle-avoidance algorithms that do not differentiate between people and other objects in the environment may fail to secure human safety in both physical and mental aspects. In this paper, a framework for designing active and human-compliant navigation behaviors is proposed, in which a set of safety strategies is put forward to guarantee human physical safety and mental comfort. Based on a questionnaire study, several important pre-collision safety criteria are selected according to the subjects' interpretation in terms of social acceptability. These criteria are characterized quantitively and computed before being integrated into a unified cost grid for safe motion control. These safety strategies not only explore collision-free paths, but also incorporate social conventions into robot navigational behaviors, which will significantly improves humans' safety feeling, regarding the...
TL;DR: From the experimental results, it is confirmed that the Waseda Saxophonist Robot no. 1 is capable of producing a saxophone sound nearly similar in terms of pitch and volume to the performance of a human player.
Abstract: The research on the Waseda Flutist Robot, since 1990, is an approach to understand human motor control from an engineering point of view, as well as introducing novel ways of musical teaching. More recently, the authors have proposed as a long-term goal the aim to enable musical performance robots to interact with musical partners. For this purpose, we present two research approaches: implementing more advanced cognitive capabilities on the Waseda Flutist Robot no. 4 Refined IV (WF-4RIV) (i.e., visual/aural processing) and developing a new musical performance robot (i.e., duet performance). In this paper, we have focused our research on developing an anthropomorphic saxophonist robot as a benchmark to better understand how the interaction with musical partners can be facilitated. As a result, we have developed the Waseda Saxophonist Robot no. 1 (WAS-1) with 15 d.o.f. that mechanically simulates the organs involved during saxophone playing. In this paper, we present the details of the mechanical design of ...
TL;DR: A three-dimensional (3-D) odometry system for wheeled robots on loose soil in an application of planetary exploration is described and the results of experiments in indoor (sandbox) and outdoor (seashore) environments are introduced.
Abstract: In this paper, the development of a three-dimensional (3-D) odometry system for wheeled robots on loose soil in an application of planetary exploration is described. When a wheeled robot operates i...
TL;DR: This paper demonstrates an automatic fabrication method of bucky gel devices based on a printing method and investigates the printing of complicated shapes and three-dimensional electrode patterns through experiments.
Abstract: A bucky gel actuator is a novel electro-active polymer (EAP), which is a low-voltage-driven dry soft actuator. In addition, the bucky gel device generates electromotive force when bending and then ...
TL;DR: This work presents, for the first time, a formal justification for a control strategy based on velocity and current inner loops driven by proportional controllers.
Abstract: In this note we are concerned with the control of a non-holonomic mobile robot, including the kinematic and the mechanical models of the robot as well as the electrical dynamics of the brushed DC motors used as actuators. We present, for the first time, a formal justification for a control strategy based on velocity and current inner loops driven by proportional controllers. Although this strategy is well known and very common in practice, a formal stability analysis supporting these ideas had not been presented until now.
TL;DR: This paper introduces a new approach to developing a fast gait for a quadruped robot using genetic programming (GP), and proposes a seemingly more efficient approach that optimizes joint trajectories instead of locus-related parameters in Cartesian space, using GP.
Abstract: This paper introduces a new approach to developing a fast gait for a quadruped robot using genetic programming (GP). Planning gaits for legged robots is a challenging task that requires optimizing parameters in a highly irregular and multi-dimensional space. Several recent approaches have focused on using genetic algorithms (GAs) to generate gaits automatically and have shown significant improvement over previous gait optimization results. Most current GA-based approaches optimize only a small, pre-selected set of parameters, but it is difficult to decide which parameters should be included in the optimization to get the best results. Moreover, the number of pre-selected parameters is at least 10, so it can be relatively difficult to optimize them, given their high degree of interdependence. To overcome these problems of the typical GA-based approach, we have proposed a seemingly more efficient approach that optimizes joint trajectories instead of locus-related parameters in Cartesian space, using GP. Our...
TL;DR: Experimental results show that the feature detection method proposed in this paper can autonomously detect features in unknown environments reasonably well.
Abstract: For successful simultaneous localization and mapping (SLAM), perception of the environment is important. This paper proposes a scheme to autonomously detect visual features that can be used as natu...