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Surgical procedures with navigation or robot system support usually require pre-operative planning data. This data can be acquired with imaging techniques such as computed tomography (CT), the current gold standard due to its high precision. With such imaging data, access trajectories, implant positions, individual milling paths, etc. can be computed. We present a novel ultrasound-based method to...
A task-oriented robot-assisted therapy environment to support activities of daily living tasks was developed with the goals of addressing some of the shortcomings of current robotic therapy systems. An important aspect of making these environments work is the implementation of trajectory planning algorithms that support the naturally curving wrist movement seen in real life functional tasks. We explore...
We propose a framework for skill synthesis for robots that exploits the human capacity to learn novel control tasks. The conceptual idea is to incorporate the target robotic platform into the experimenter's body schema so that it can be controlled effortlessly as if the robot were a part of the body. Once this stage is achieved, the dexterity on a task exhibited with the new external limb -the robot-...
In this paper we present a robot that is able to perform daily manipulation tasks in a home environment, such as opening doors and drawers. Taking as input a simplified object model and the task to perform, the robot automatically finds a grasp suitable for the task and performs it. For this, we identify a set of hand preshapes and classify them according to the grasp wrench space they generate. Given...
This paper presents aspects related to the generation and tracking of closed trajectories over an arbitrary surface of unknown geometry. Such a capacity is required in some of the most important industrial robotic tasks, like the cutting or welding of commercial plates. Previous work has shown how a calibration-free, vision-based method can be combined with an optimal geodesic-mapping approach, in...
In the teleoperated minimally invasive surgery systems, measurement and display of sense of force to the operator is a problem. In this paper, a manipulator for supporting forceps has been developed which has 3-DOFs actuated by pneumatic cylinders. We also developed a master manipulator using a delta mechanism and a gimbal mechanism with a force sensor and motors with reduction gears. In the developed...
In this paper, we present a new hybrid visual servoing algorithm for robot arm positioning task. Hybrid methods in visual servoing partially combine the 2D and 3D visual information to improve the performance of the traditional image-based and position-based visual servoing. Our algorithm is superior to the state of the art hybrid methods. The objective function has been designed to include the full...
A safe robot arm can be achieved by either passive or active compliance. The passive compliance systems composed of purely mechanical elements often provide faster and more reliable responses for dynamic collision than the active ones involving sensors and actuators. Since both positioning accuracy and collision safety are important, a robot arm should exhibit very low stiffness when subjected to...
The problem of object caging is defined as a problem of designing a formation of fingers to restrict an object within a bounded space. Assuming two pointed fingers and a rigid polygonal or polyhedral object, this paper addresses the problem of two-finger squeezing caging, i.e., to characterize all possible formations of the fingers that are capable of caging the object via limiting their separation...
A new method for calculating the collision free areas of a manipulator's configuration space (C-space) is demonstrated in this paper. Rather than mapping a point obstacle to an n-dimensional surface in the C-space, the dual problem is considered. That is, regions of the C-space that are guaranteed to be collision free are determined. Whilst some configurations that are collision free are not captured...
Kikuuwe and Fujimoto have introduced proxy-based sliding mode control. It combines responsive and accurate tracking during normal operation with smooth, slow recovery from large position errors that can sometimes occur after abnormal events. The method can be seen as an extension to both conventional PID control and sliding mode control. In this paper, proxy-based sliding mode control is used to control...
This paper reports on the position and force control of pneumatic artificial muscles reinforced by straight glass fibers. This type of artificial muscle has a greater contraction ratio and power and a longer lifetime than conventional McKibben types. However, these muscles are highly non-linear; hence, it is difficult to use them in a mechanical system. Furthermore, this actuator has a high compliance...
The control of humanoid manipulators is very challenging due to the large number of degrees of freedom and the resulting redundancy. Using joint-level control complex planning algorithms are needed to accomplish tasks. For intuitive operation and hence short development times of applications high-level control interfaces are needed. Furthermore, for many tasks it is desirable to define an impedance...
Calibration is an essential issue to use a robot to accomplish some tasks with high accuracy requirements. An important part of calibration process is measuring the actual pose of some parts of the robot. Many sensors have been used for measuring, for some of them, extra objects need installing on the robot, so it's possible to implement extra accuracy problems. While choosing coordinate measure machine...
The payload oscillation inherent to all cranes makes it challenging for human operators to manipulate pay-loads quickly, accurately, and safely. Under certain conditions, the problem is compounded when the payload creates a double-pendulum effect. This paper presents an input-shaping control method for suppressing double-pendulum payload oscillations. Local and teleoperation experiments performed...
This paper describes the design of a new telepresence vision system developed to realize a higher immersive feeling for telemanipulation tasks. A new measure of 'permissible visual errors' was defined. Making use of this new measure, a minimal vision system is designed, containing only the strictly necessary DOF's (degrees of freedom) while keeping the vision errors below an experimentally obtained...
In this paper, we apply a general framework for building complex whole-body control for highly redundant robot, and we propose to implement it for visually-guided grasping while walking on a humanoid robot. The key idea is to divide the control into several sensor-based control tasks that are simultaneously executed by a general structure called stack of tasks. This structure enables a very simple...
This paper presents an approach for producing virtual fixture based on simulated plasticity, which can be used for assisting precise manual manipulations performed by human users through haptic interfaces. The fixture acts as a guide to help path-tracing tasks and as a wall for preventing a tool from entering a specified region, but the user can move against the fixture by intentionally producing...
Hip joint surgeries are commonplace in our aging society. Robotic hip joint surgery is performed to cut bone precisely and is expected to be performed as minimally invasive treatment. Minimally invasive hip joint surgery needs operating space between muscle tissues and the bone around hip joint. In this paper a prototype of an articulated muscle-retracting robot for minimally invasive RAO (rotational...
This paper presents the resolve spatial constraints (RSC) algorithm for manipulation planning in a domain with movable obstacles. Empirically we show that our algorithm quickly generates plans for simulated articulated robots in a highly nonlinear search space of exponential dimension. RSC is a reverse-time search that samples future robot actions and constrains the space of prior object displacements...
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