Advanced Robotics

Takuma, Takashi; Takamine, Ken; Masuda, Tatsuya

doi: 10.1080/01691864.2014.908741pmid: N/A

Active sensing, in which a robot pushes an object and senses the reaction force or joint angle by means of the force sensor at the point of the contact or on the joint, is one of the effective approaches to estimate the physical properties of an object, such as its compliance. A compliant joint driven by elastic actuators has an advantage over a rigid joint driven by a motor with a high gear ratio in that it absorbs the reaction force, and thus avoids any joint damage during active sensing. However, this approach is not suitable for either rigid joint or a compliant joint because the sensors attached to the contact point and the joint tend to break, owing to iterative contact or an excessive force. Here, this paper adopts a one-degree-of-freedom joint mechanism driven by elastic pneumatic actuators, and focuses on the passivity of the elastic pneumatic actuator, in which the pressure is changed when force is applied, after which it is deformed. By utilizing the passivity of the actuators under a number of conditions, this paper derives multiple regression models of the force and the angle, using the pressures before and after force is applied to the joint mechanism. Experimental results present that the contact information can be estimated from the pressure values and that the joint mechanism can detect the elasticity of an object using the regression models. We also observe the range of the elasticity of the object by tuning the joint compliance. This approach provides a robot hand that can estimate the contact information, including the force and joint displacement, avoiding the failure of the sensors.

Guyonneau, Rémy; Lagrange, Sébastien; Hardouin, Laurent; Lucidarme, Philippe

doi: 10.1080/01691864.2014.908742pmid: N/A

This paper presents a set membership method (named Interval Analysis Localization (IAL)) to deal with the global localization problem of mobile robots. By using a LIDAR (LIght Detection And Ranging) range sensor, the odometry and a discrete map of an indoor environment, a robot has to determine its pose (position and orientation) in the map without any knowledge of its initial pose. In a bounded error context, the IAL algorithm searches a set of boxes (interval vector), with a cardinality as small as possible that includes the robot’s pose. The localization process is based on constraint propagation and interval analysis tools, such as bisection and relaxed intersection. The proposed method is validated using real data recorded during the CAROTTE challenge, organized by the French ANR (National Research Agency) and the French DGA (General Delegation of Armament). IAL is then compared with the well-known Monte Carlo Localization showing weaknesses and strengths of both algorithms. As it is shown in this paper with the IAL algorithm, interval analysis can be an efficient tool to solve the global localization problem.

Asano, S.; Okamoto, S.; Matsuura, Y.; Yamada, Y.

doi: 10.1080/01691864.2014.913502pmid: N/A

For industrial purposes such as product design, texture displays should deliver a quality sense of touch to users. We have developed a vibrotactile texture display that uses real materials such as fabric, wood, and leather to enable the presentation of quality textures to users. By applying two types of vibrotactile stimuli to users’ finger pads through the materials, their fine and macro roughness sensations can be selectively modified while maintaining their original perceptual characteristics. This approach is effective for different types of textures such as paper, wood, leather, and cloth unless they possess strong damping properties that may attenuate the vibratory stimuli applied through them.

Penning, Ryan S.; Zinn, Michael R.

doi: 10.1080/01691864.2014.913503pmid: N/A

Continuum manipulators continue to gain popularity due to their ability to operate within difficult to reach environments, and their inherent safety characteristics. However, their flexible nature makes them prone to both steady-state positioning errors and undesirable vibrations. We propose a combined control system incorporating both a tracking position controller to reduce steady-state error, and a modal-space controller to improve the dynamic properties of the manipulator. To this end, we develop a lumped parameter model for use as a modal-space observer. Simulation results based on a planar two-segment manipulator and experimental results from a single-segment manipulator both show marked improvement using our combined approach. The improvements observed in both simulation and experimental results include reduced settling time, higher bandwidth trajectory control capability, and an improved response to external disturbances.

Kim, Yonghyun; Mohan, Santhakumar; Kim, Jinwhan

doi: 10.1080/01691864.2014.913504pmid: N/A

For an underwater vehicle-manipulator system, which consists of an underwater vehicle equipped with a manipulator, it is important to regulate the position of the manipulator’s end-effector with respect to a given target position in many interactive operations. This paper presents a task space-based approach for designing a controller that ensures that the end-effector of an underwater vehicle-manipulator system maintains its position in the presence of unknown ocean currents and uncertainties without the explicit use of a disturbance observer. A feedback linearizing control in task coordinates is used, and an extended Kalman filter (EKF) is employed as a state observer. The proposed approach can also be applied to dynamic positioning or controlled weathervaning of a surface ship whose motion is affected by environmental disturbances. To demonstrate the validity and effectiveness of the proposed approach, numerical simulations and experimental tests were carried out and their results are shown.

Lu, Y.; Li, X.P.

doi: 10.1080/01691864.2014.908743pmid: N/A

A novel 6-DoF parallel manipulator I with three planar limbs is proposed and its dynamics is analyzed systematically. First, its characteristics and DoF are analyzed and calculated. Second, the formulae for solving kinematics of the moving platform and the planar limbs are derived. Third, the formulae for solving the inertial wrench applied on the planar limbs and the moving platform are derived, and dynamics formula is derived for solving dynamic active forces applied onto the planar limbs. Fourth, a singularity of the proposed parallel manipulator is determined and analyzed. Fifth, an analytic example is given for solving the kinetostatics and dynamics of the proposed parallel manipulator, and the solved results are analyzed and verified by the simulation mechanism. Finally, a workspace is constructed and analyzed by comparing with an existing 6-DoF parallel manipulator.