Showing papers in "Advanced Robotics in 2012"
TL;DR: The prototype of a robot arm has been built based on an artificial muscular hydroStat inspired to the muscular hydrostat of the Octopus vulgaris, which emerges as a good model for embodied intelligence and for soft robotics.
Abstract: The octopus is a marine animal whose body has no rigid structures. It has eight arms composed of a peculiar muscular structure, named a muscular hydrostat. The octopus arms provide it with both locomotion and grasping capabilities, thanks to the fact that their stiffness can change over a wide range and can be controlled through combined contractions of the muscles. The muscular hydrostat can better be seen as a modifiable skeleton. Furthermore, the morphology the arms and the mechanical characteristics of their tissues are such that the interaction with the environment (i.e., water) is exploited to simplify control. Thanks to this effective mechanism of embodied intelligence, the octopus can control a very high number of degrees of freedom, with relatively limited computing resources. From these considerations, the octopus emerges as a good model for embodied intelligence and for soft robotics. The prototype of a robot arm has been built based on an artificial muscular hydrostat inspired to the muscular ...
772 citations
TL;DR: The state-of-the-art of the main research advances in lower-limbs human assistance is presented and the seamless integration of wearable robots in ambient intelligence spaces appears as one of the major challenges for ubiquitous environments and ambient assisted living.
Abstract: Recent technological advances made necessary the use of robots in various types of applications. Unlike traditional robot-like scenarios dedicated to industrial applications with repetitive tasks, the current focus of attention is on applications that require close human interactions. One of the main fields of such applications concerns assisting and rehabilitating of dependent/elderly persons. In this study, the state-of-the-art of the main research advances in lower-limbs human assistance is presented. This includes a review on research covering mainly lower-limb actuated exoskeletons. Some case studies related to full-limb exoskeletons are presented as well. Lower-limb movement restoration using functional electrical stimulation and treadmill-based rehabilitation devices is also investigated. In addition, the seamless integration of wearable robots in ambient intelligence spaces appears as one of the major challenges for ubiquitous environments and ambient assisted living. Some open issues related to t...
105 citations
TL;DR: The central component of the planning framework is a best-first algorithm that performs a search of the contacts to be added or removed at each step, following an input collision-free guide path, and making calls to an optimization-based inverse kinematics solver under static equilibrium constraints.
Abstract: We aim at planning multi-contact sequences of stances and postures for humanoid robots. The output sequence defines the contact transitions that allow our robot to realize different kind of tasks, ranging from biped locomotion to dexterous manipulation. The central component of the planning framework is a best-first algorithm that performs a search of the contacts to be added or removed at each step, following an input collision-free guide path, and making calls to an optimization-based inverse kinematics solver under static equilibrium constraints. The planner can handle systems made of multiple robots and/or manipulated objects through a centralized multi-agent approach, opening the way for multi-robot collaborative locomotion and manipulation planning. Results are presented in virtual environments, with discussion on execution on the real robot HRP-2 in an example situation.
103 citations
TL;DR: The third generation of Pleated Pneumatic Artificial Muscles (PPAM), which has been developed to simplify the production over the first and second prototype, presents better force-to-mass and energy to mass ratios than Festo models.
Abstract: This paper introduces the third generation of Pleated Pneumatic Artificial Muscles (PPAM), which has been developed to simplify the production over the first and second prototype. This type of artificial muscle was developed to overcome dry friction and material deformation, which is present in the widely used McKibben muscle. The essence of the PPAM is its pleated membrane structure which enables the muscle to work at low pressures and at large contractions. In order to validate the new PPAM generation, it has been compared with the mathematical model and the previous generation. The new production process and the use of new materials introduce improvements such as 55% reduction in the actuator’s weight, a higher reliability, a 75% reduction in the production time and PPAMs can now be produced in all sizes from 4 to 50 cm. This opens the possibility to commercialize this type of muscles so others can implement it. Furthermore, a comparison with experiments between PPAM and Festo McKibben muscles...
93 citations
TL;DR: A musculoskeletal robot with elastic blade feet controlled by feedforward motor command is used as a tool to investigate how animals control their complex body and shows that acceleration causes anterior inclination after the first step.
Abstract: In this study, a musculoskeletal robot is used as a tool to investigate how animals control their complex body. Sprinting is a challenging task that requires maximizing the potential resources of a musculoskeletal structure. Our approach to robotic sprinting is the Athlete Robot — a musculoskeletal robot with elastic blade feet controlled by feedforward motor command. We use a catapult launcher to provide a stable start to a sprint, and then examine the relation between the initial velocity imparted by the launcher and the change in orientation of the robot. We also investigate the influence of the change in elasticity of the blade foot. The results show that acceleration causes anterior inclination after the first step. The elasticity of the foot dominates the duration of the support phase. The musculoskeletal system of the Athlete Robot is modified to suit catapulted running. Based on the results from real robot experiments, we can provide a consistent propelling force using the catapult launcher. We de...
58 citations
TL;DR: A novel collision detection algorithm is proposed which can distinguish intended contacts and unexpected collisions and, in most cases, the external force during a collision shows a noticeably faster rate of change than that during an intended contact, and using this difference, the proposed observer can distinguish one from the other.
Abstract: Industrial and service robots often physically interact with humans, and thus, human safety during these interactions becomes significantly important. Several solutions have been proposed to guarantee human safety, and one of the most practical, efficient solutions is the collision detection using generalized momentum and joint torque sensors. This method allows a robot to detect a collision and react to it as soon as possible to minimize the impact. However, the conventional collision detection methods cannot distinguish between intended contacts and unexpected collisions, and thus they cannot be used during certain tasks such as teaching and playback or force control. In this paper, we propose a novel collision detection algorithm which can distinguish intended contacts and unexpected collisions. In most cases, the external force during a collision shows a noticeably faster rate of change than that during an intended contact, and using this difference, the proposed observer can distinguish one ...
48 citations
TL;DR: An approach to simultaneously estimate a map of the environment, the position of the on-board sensors of the robot, and its kinematic parameters and it is able to adapt to non-stationary changes of the configuration.
Abstract: The calibration parameters of a mobile robot play a substantial role in navigation tasks. Often these parameters are subject to variations that depend either on changes in the environment or on the load of the robot. In this paper, we propose an approach to simultaneously estimate a map of the environment, the position of the on-board sensors of the robot, and its kinematic parameters. Our method requires no prior knowledge about the environment and relies only on a rough initial guess of the parameters of the platform. The proposed approach estimates the parameters online and it is able to adapt to non-stationary changes of the configuration. We tested our approach in simulated environments and on a wide range of real-world data using different types of robotic platforms.
42 citations
TL;DR: A sliding mode filter for removing noise that effectively removes impulsive noise and highfrequency noise, producing a smaller phase lag than linear filters and is less prone to overshoot than previous sliding mode filters.
Abstract: This paper presents a sliding mode filter for removing noise. It effectively removes impulsive noise and highfrequency noise, producing a smaller phase lag than linear filters. In addition, it is less prone to overshoot than previous sliding mode filters and it does not produce chattering. It is computationally inexpensive and thus suitable for real-time applications. The proposed sliding mode filter employs a quadratic surface as its sliding surface, which is designed so that the output converges to the input in finite time when the input value is constant. Its algorithm is derived by using the backward Euler discretization, which can be used to prevent chattering. The effectiveness of the filter was shown by experiments using an ultrasonic sensor and an optical encoder.
41 citations
TL;DR: A soft active connection mechanism based on electroadhesion that uses electrostatic forces to connect modules is proposed and is suitable as a connection principle for lightweight modules when efficiency over a wide range of softness, tolerance to alignment and easy detachment are desired.
Abstract: To date, most modular robotic systems lack flexibility when increasing the number of modules due to their hard building blocks and rigid connection mechanisms. In order to improve adaptation to environmental changes, softness on the module level might be beneficial. However, coping with softness requires fundamental rethinking the way modules are built. A major challenge is to develop a connection mechanism that does not limit the softness of the modules, does not require precise alignment and allows for easy detachment. In this paper, we propose a soft active connection mechanism based on electroadhesion. The mechanism uses electrostatic forces to connect modules. The method is easy to implement and can be integrated in a wide range of soft module types. Based on our experimental results, we conclude that the mechanism is suitable as a connection principle for light-weight modules when efficiency in a wide range of softness, tolerance to alignment and easy detachment are desired. The main contributions of this article are (i) the qualitative comparison of different connector principles for soft modular robots, (ii) the integration of electroadhesion, featuring a novel electrode pattern design, into soft modules, and (iii) the demonstration and characterization of the performance of functional soft module mockups including the connection mechanism.
37 citations
TL;DR: Main bionic characteristics extracted from the cow-nosed ray are fulfilled by the prototype and verified by experiments, including the mechanical design and the control method.
Abstract: This paper aims to design a novel bionic fish propelled by oscillating paired pectoral fins. Flapping motion deformation of the nature sample, the cow-nosed ray, is realized with simple mechanical structure through optimization. Locomotion analysis of the nature sample under linear cruise swimming conditions is carried out. Simplified mathematical models of the pectoral fin are obtained to be the design foundation of the bionic fin rays and the bionic fish. The number of fin rays is decided according to the passing kinematic wave shape and number. Distance and structure parameters are optimized, and determined by the minimum area error method. A novel two-stage slide–rocker mechanism is designed to fulfill the driving requirements with only one servo motor. System design of a new bionic fish robot is presented, including the mechanical design and the control method. Main bionic characteristics extracted from the cow-nosed ray are fulfilled by the prototype and verified by experiments.
35 citations
TL;DR: This work presents a method of defining body coordinate frames that departs from the typical convention of rigidly fixing a frame to a link on the robot, and instead defines a body frame that is based on the averaged position of all of the robot’s links.
Abstract: Intuitively representing the motion of a snake robot is difficult. This is in part because the internal shape changes that the robot uses to locomote involve the entire body and no single point on the robot intuitively represents the robot’s pose at all times. To address this issue, we present a method of defining body coordinate frames that departs from the typical convention of rigidly fixing a frame to a link on the robot, and instead define a body frame that is based on the averaged position of all of the robot’s links. This averaged frame serves as a virtual chassis that effectively isolates the internal motion of the robot’s shape changes from the external motion, due to the robot’s interaction with its surroundings. This separation of motion allows much simpler models—such as those derived for wheeled vehicles—to accurately approximate the motion of the robot as it moves through the world. We demonstrate the practical advantages of using the virtual chassis body frame by estimating the pit...
TL;DR: A technique that uniformly controls a team of autonomous sensor platforms charged with the dual task of searching for and then tracking a moving target within a recursive Bayesian estimation framework that can smoothly change its control actions even during transitions between SAT.
Abstract: We present a technique that uniformly controls a team of autonomous sensor platforms charged with the dual task of searching for and then tracking a moving target within a recursive Bayesian estima...
TL;DR: The kinematic analysis of the screw drive mechanism has been conducted on the basis of the basic principle of helical motion in curved pipes to derive the optimal spring stiffness for the robot to pass through the curved pipe and to climb up in the vertical pipe.
Abstract: Various in-pipe robots used for inspection have been developed as a preventive measure against leakage. To expand the use of these robots in small pipelines, high environmental adaptability via a simple structure must be achieved. One solution, using the screw drive mechanism, has been focused on because it requires only one motor. However, the screw drive mechanism cannot achieve complex motion because of its 1-d.o.f. Therefore, existing screw drive in-pipe robots cannot pass through curved pipes with a small curvature radius. To overcome this problem, the kinematic analysis of the screw drive mechanism has been conducted on the basis of the basic principle of helical motion in curved pipes. From the analysis, the relationship among the spring stiffness, motor torque, robot length and static friction on the inner pipe wall is established for the design of stiffness of the supporting springs. The optimal spring stiffness is, thus, derived for the robot to pass through the curved pipe and to climb up in th...
TL;DR: An anthropomorphic muscular–skeletal robotic upper limb is described and expected to have comparable anisotropic compliance to that of a human, which can be utilized for realization of human-like adaptive behavior.
Abstract: In this paper, we describe an anthropomorphic muscular–skeletal robotic upper limb and focus on its soft interaction with the environment. Two experiments are conducted to demonstrate the ability of the system: object recognition by dynamic touch and adaptive door opening. The first experiment shows that the compliant robot is advantageous for categorizing an object by shaking and the second experiment shows that the human-comparable compliant robot can open a door without precise control. The robot is expected to have comparable anisotropic compliance to that of a human, which can be utilized for realization of human-like adaptive behavior.
TL;DR: To operate the system with the user, human walking analysis and intention signal acquisition methods for actuating the proposed system are developed and a sensing data estimation strategy is applied to synchronize the exoskeleton system with a user correctly.
Abstract: This study proposes an under-actuated wearable exoskeleton system to carry a heavy load. To synchronize that system with a user, a feasible modular-type wearable system and its corresponding sensor systems are proposed. The design process of the modular-type exoskeleton for lower extremities is presented based on the considered requirements. To operate the system with the user, human walking analysis and intention signal acquisition methods for actuating the proposed system are developed. In particular, a sensing data estimation strategy is applied to synchronize the exoskeleton system with a user correctly. Finally, several experiments were performed to evaluate the performance of the proposed exoskeleton system by measuring the electromyography signal of the wearer's muscles while walking on level ground and climbing up stairs with 20- to 40-kg loads, respectively.
TL;DR: This work shows how the challenge of playing minigolf can be efficiently tackled by first learning a basic hitting motion model, and then learning to adapt it to different situations, and demonstrates the generalization ability of the model in various situations.
Abstract: A current trend in robotics is to define robot motions so that they can be easily adopted to situations beyond those for which the motion was originally designed. In this work, we show how the challenging task of playing minigolf can be efficiently tackled by first learning a basic hitting motion model, and then learning to adapt it to different situations. We model the basic hitting motion with an autonomous dynamical systems, and solve the problem of learning the parameters of the model from a set of demonstrations through a constrained optimization. To hit the ball with the appropriate hitting angle and speed, a nonlinear model of the hitting parameters is estimated based on a set of examples of good hitting parameters. We compare two statistical methods, Gaussian Process Regression and Gaussian Mixture Regression in the context of inferring the hitting parameters for the minigolf task. We demonstrate the generalization ability of the model in various situations. We validate our approach on the 7 Degre...
TL;DR: Results from several computer simulations with real sound wave recording from a human experimenter show that the robot could successfully achieve being imitated by the proposed method even if interacting with a caregiver who would seldomly imitate its utterances.
Abstract: Regardless of interaction with less frequent imitative caregivers, infants can obtain the vowels of the caregivers' mother tongues by finding the correspondence between their own vowels and the caregivers' vowels. This paper proposes a learning method based on auto-mirroring bias (AMB) with a self-evaluation mechanism to find such correspondence. AMB is the robot's anticipation of being imitated by its caregiver and has a role of narrowing the candidates for the correspondence. The self-evaluation mechanism biased by AMB works as outlier (incorrect mapping) rejection, expecting that the outliers appear less consistently than the correct mappings do in the interaction. Results from several computer simulations with real sound wave recording from a human experimenter show that the robot could successfully achieve being imitated by the proposed method even if interacting with a caregiver who would seldomly imitate its utterances.
TL;DR: A cable mechanism that realizes a nonlinear rotational spring from a linear translational spring that is pulled by a cable wound around a non-circular spool that synthesizes a prescribed torque–angle relationship.
Abstract: In this paper we present a cable mechanism that realizes a nonlinear rotational spring from a linear translational spring. The spring is pulled by a cable wound around a non-circular spool, which is rigidly attached to the joint. The non-circular shape of the spool induces a nonlinear relationship between its angular position and the torque created by the tension of the cable. Depending on the shape of the spool, various torque–angle relationships can be realized. We show that for a given nonlinear torque–angle relationship, there is an explicit expression (closed-form solution) of the shape of the spool that synthesizes this function. First, we present the geometry of the problem. Then, we derive the methodology to calculate the shape of the spool to synthesize a prescribed torque–angle relationship. Finally, we verify the design methodology by experiments with three different spools realizing a constant force spring, an exponential softening spring and a cubic polynomial spring. We discuss the possible ...
TL;DR: For multimodal concept formation, multimodals latent Dirichlet allocation using Gibbs sampling is extended to an online version and makes it possible for the robot to learn object concepts naturally in everyday operation in conjunction with a small amount of linguistic information from human users.
Abstract: In this paper, we propose a robot that acquires multimodal information, i.e. visual, auditory, and haptic information, fully autonomously using its embodiment. We also propose batch and online algorithms for multimodal categorization based on the acquired multimodal information and partial words given by human users. To obtain multimodal information, the robot detects an object on a flat surface. Then, the robot grasps and shakes it to obtain haptic and auditory information. For obtaining visual information, the robot uses a small hand-held observation table with an XBee wireless controller to control the viewpoints for observing the object. In this paper, for multimodal concept formation, multimodal latent Dirichlet allocation using Gibbs sampling is extended to an online version. This framework makes it possible for the robot to learn object concepts naturally in everyday operation in conjunction with a small amount of linguistic information from human users. The proposed algorithms are impleme...
TL;DR: This paper proposes a robot that imitates the peristaltic crawling of an earthworm and uses an artificial rubber muscle as an actuator and shows that it had the ability to move the endoscope.
Abstract: The number of large intestine cancer patients has been increasing steadily. An endoscope can be used to diagnose as well as to treat the diseased part of the intestine. A large intestine endoscope is used mainly to examine cancer of the large intestine. However, many doctors have problems handling an endoscope. To resolve this issue, there is demand for a robotic application to assist in inserting the endoscope and straightening the slack from the intestine. We propose a robot that imitates the peristaltic crawling of an earthworm and uses an artificial rubber muscle as an actuator. By attaching the robot to an existing endoscope, it will be possible to move the endoscope forward and pull up the intestine simultaneously, while retaining the functions of the existing endoscope. In this paper, we test the forward and pulling movements of a sliding-air-tube robot in a large intestine of model to evaluate its performance. From these experiments, the robot equipped with the endoscope of 11 mm in the d...
TL;DR: A resonant-type SIDM actuator driven with hard-type PZTs to realize high-speed and powerful operation and to generate a high-power ultrasonic output.
Abstract: A smooth impact drive mechanism (SIDM) is a unique piezoelectric actuator that is widely used as a camera focusing mechanism, cell phone lens movement mechanism, etc. This principle enables a compact driving mechanism; however, it cannot generate high-speed movement because a soft-type multilayered piezoelectric transducer (PZT) is utilized at off-resonant movement. This paper proposes a resonant-type SIDM actuator driven with hard-type PZTs to realize high-speed and powerful operation. The fundamental principle is also based on the conventional SIDM; therefore, a saw-shaped movement is required. To generate a high-power ultrasonic output, two Langevin transducers are adopted instead of a soft-type multilayered PZT. One Langevin transducer was a stator and the other was slider whose tip was adhered to a carbon fiber reinforced plastic (CFRP) rod. The CFRP rod was connected to the stator transducer with the frictional force. To obtain quasi-saw-shaped vibration, the longitudinal vibration for each Langevin...
TL;DR: It is shown that wheeled locomotion has an 8-times higher energy efficiency than the ordinary crawl gait, and the specific resistance of Roller-Walker is compared with other walking robots described in the literature.
Abstract: Roller-Walker is a leg–wheel hybrid mobile robot using a passive wheel equipped on the tip of each leg. The passive wheel can be transformed into sole mode by rotating the ankle roll joint when Roller-Walker walks on a rough terrain. This paper discusses the energy efficiency of locomotion in wheeled mode. We define a leg trajectory to produce forward straight propulsion, and discuss the relationships between the parameters of the leg trajectory and energy efficiency of the propulsion using a dynamics simulator. We find optimum parameter sets where optimization criterion is specific resistance. The results indicate that faster locomotion achieves higher energy efficiency. We then carry out hardware experiments and empirically derive the experimental specific resistance. We show that wheeled locomotion has an 8-times higher energy efficiency than the ordinary crawl gait. Finally, we compare the specific resistance of Roller-Walker with other walking robots described in the literature.
TL;DR: This work uses edge-point-based stereo simultaneous localization and mapping to obtain simultaneously occupancy information and robot ego-motion estimation and uses two-dimensional occupancy grid maps generated from three-dimensional point clouds obtained by a stereo camera.
Abstract: We present a mobile robot localization method using only a stereo camera. Vision-based localization in outdoor environments is a challenging issue because of extreme changes in illumination. To cope with varying illumination conditions, we use two-dimensional occupancy grid maps generated from three-dimensional point clouds obtained by a stereo camera. Furthermore, we incorporate salient line segments extracted from the ground into the grid maps. The grid maps are not significantly affected by illumination conditions because occupancy information and salient line segments can be robustly obtained. On the grid maps, a robot's poses are estimated using a particle filter that combines visual odometry and map matching. We use edge-point-based stereo simultaneous localization and mapping to obtain simultaneously occupancy information and robot ego-motion estimation. We tested our method under various illumination and weather conditions, including sunny and rainy days. The experimental results showed the effect...
TL;DR: This work presents a method of simultaneous localization and mapping (SLAM) in a large indoor environment using a Rao-Blackwellized particle filter (RBPF) along with a line segment as a landmark, which provides reliable SLAM and compact map representation even in a cluttered environment.
Abstract: We present a method of simultaneous localization and mapping (SLAM) in a large indoor environment using a Rao-Blackwellized particle filter (RBPF) along with a line segment as a landmark. To represent the environment in a compact form, we use only two end points of a line segment, thus reducing computational cost in modeling line segment uncertainty. With a modified scan point clustering method, the proposed adaptive iterative end point fitting contributes to the estimation of line parameters by considering noisy scan points near end points. Thus, by line segment matching the robot is localized well in a local frame. We also introduce an online and offline method of global line merging, which provides a more compact map by removing spurious lines and merging collinear lines. Each of our approaches is efficiently integrated into the proposed RBPF-SLAM framework. In experiments with well-known data sets, the proposed method provides reliable SLAM and compact map representation even in a cluttered environment.
TL;DR: The proposed method concerns intelligent vehicle applications, where the relative distance between sensor frames can be significant, and circular calibration targets are used in order to make full use of the perception properties of both lidar and video cameras.
Abstract: This article presents a novel approach for solving the problem of 3D alignment between video and lidar sensors. The proposed method concerns intelligent vehicle applications, where the relative distance between sensor frames can be significant. Circular calibration targets are used in order to make full use of the perception properties of both lidar and video cameras, which greatly simplifies the calibration task. The method determines the relative pose in rotation and translation of the sensors, using sets of corresponding circular features acquired for several configurations of the targets. A performance analysis in simulation and an error propagation analysis are carried out. The calibration procedure is tested on different configurations, and the calibration accuracy and estimation of confidence intervals are evaluated on real data.
TL;DR: A new SLAM based on ceiling vision (cv-SLAM) is proposed, and an efficient update method called 'double update' is proposed to improve the SLAM performance.
Abstract: For simultaneous localization and mapping (SLAM) based on the extended Kalman filter, the size of the state vector is an essential factor because the feasibility depends on it. In this paper, a new SLAM based on ceiling vision (cv-SLAM) is proposed. To keep the size of the state vector compact, the boundaries between ceiling and walls are used as landmarks for visual SLAM (vSLAM). The ceiling boundaries are robust to illuminative variations and they are not as numerous as the point features. Some constraints are imposed on the features based on the characteristics of the ceiling boundaries and an efficient update method called 'double update' is proposed to improve the SLAM performance. The basic idea of the double update is to fully utilize the intersections of the boundary features. Finally, the proposed SLAM is applied to some simulations and experiment, and its effectiveness is demonstrated through them.
TL;DR: It is shown in this paper that the unified projection model proposed for central catadioptric cameras is also valid for fisheye cameras in the context of robotic applications and is shown equivalent to almost all the f isheye models.
Abstract: A wide field of view is required for many robotic vision tasks. Such an aperture may be acquired by a fisheye camera, which provides a full image compared to catadioptric visual sensors, and does not increase the size and the weakness of the imaging system with respect to perspective cameras. While a unified model exists for all central catadioptric systems, many different models, approximating the radial distortions, exist for fisheye cameras. It is shown in this paper that the unified projection model proposed for central catadioptric cameras is also valid for fisheye cameras in the context of robotic applications. This model consists of a projection onto a virtual unitary sphere followed by a perspective projection onto an image plane. This model is shown equivalent to almost all the fisheye models. Calibration with four cameras and partial Euclidean reconstruction are done using this model, and lead to persuasive results. Finally, an application to a mobile robot navigation task is proposed a...
TL;DR: A novel way to analyze parallel mechanisms with a spring spine that combines the kinematics with the statics to solve them simultaneously is proposed and it can be applied to other mechanisms with flexible spines.
Abstract: A special humanoid neck with low motion noise requirements yields a cable-driven parallel mechanism to imitate the rotational motion of a human neck. The fixed base and moving platform of the mechanism are connected by four cables and a column compression spring. The four cables are actuated separately, while the spring can support weight on the moving platform. Although similar mechanisms exist in the literature, the analysis of them is scarce because a flexible spring instead of a rigid kinematic chain is used as the spine. With the spring’s lateral buckling motion, a new approach must be adopted to solve the kinematics. In this paper, we propose a method that combines the kinematics with the statics to solve them simultaneously. The configuration of the moving platform is parameterized with four parameters, one of which is considered as parasitic motion. Using the spring’s lateral buckling equation, we can obtain the parasitic motion and solve the inverse position problem. The optimal design f...
TL;DR: This work presents a method for line-based self-localization on a soccer field that is used regularly on humanoid soccer robots, which won the RoboCup TeenSize competitions in the years 2009–2011.
Abstract: Self-localization on the field is one of the key perceptual tasks that a soccer robot, e.g. in the RoboCup competitions, must solve. This problem becomes harder, as the rules in RoboCup more and more discourage a solely color-based orientation on the field. While the field size increases, field boundary markers and goals become smaller and less colorful. For robust game play, robots, therefore, need to maintain a probabilistic pose estimate and rely on more subtle environmental clues. Field lines are particularly interesting features, because they are hardly ever completely occluded and observing them significantly reduces the number of possible poses on the field. In this work, we present a method for line-based self-localization on a soccer field. Unlike previous work, our method first recovers a line structure graph from the image. From the graph, we can then easily derive features such as lines and corners. Finally, we describe optimizations for efficient use of the derived features in a part...
TL;DR: A new robot system based on a hybrid robot that possesses the characteristic of a Cartesian coordinate robot is reported in this paper, which is used to manipulate a bone fragment for alignment and fixation purposes in femur fracture reduction surgery.
Abstract: When performing femur fracture reduction surgery, both the patient and surgeon are exposed to a great amount of radiation, which is harmful to their health. In order to reduce such radiation from the usage of an image intensifier, various robots have been proposed for femur fracture reduction surgery. Most of these robots are based on serial architecture. The low transportable load and poor accuracy are both inherent in serial robots, which makes them inappropriate for femur fracture reduction. Some parallel robots based on the 'Stewart platform' have also been developed for femur fracture reduction, but their restricted workspace limits their applicability and accessibility. To balance the accuracy, payload and workspace, a new robot system is reported in this paper. The proposed robot system consists of a 2-d.o.f. device and a 6-d.o.f. hybrid robot. The 2-d.o.f. device is used for distraction, which requires a very large force. The hybrid robot is used to manipulate a bone fragment for alignment and fix...