Abdul Muis

Eye-to-hand approach on eye-in-hand configuration within real-time visual servoing

This paper presents a framework of hand-eye relation for visual servoing with more precision, mobility, and global view. Mainly, there are two types of camera utilization for visual servoing: eye-in-hand and eye-to-hand configurations. Both have own merits and drawbacks regarding to precision and view limit that oppose each other. Based on both behaviors, this paper employs a mobile manipulator as the second robot to hold the camera. Here, the camera architecture is eye-to-hand configuration for the main robot, but mainly behaves as eye-in-hand configuration for the second robot. Having this framework, the drawback of each configuration is resolved by the benefit of the other. Here, the camera becomes mobile with more precision and global view. In addition, since there is no additional camera, the vision algorithm can be kept simple. In order to gain real-time visual servoing, this paper also addresses real-time constraints on vision system and data communication between robot and vision. Here, a hexagon pattern of artificial marker with a simplified image processing is developed. A grasp positioning problem is considered with position-based dynamic look and move visual control through object pose estimation. The system performance is validated by the experimental result.

Teleoperation with soft sensation based on Transformer and Gyrator Theorems

Ideally, a bilateral teleoperation would be completely transparent, so the operators feel that they are directly interacting with the remote task, However, the delay presence in interconnection between both systems, degrade system performance. There have been two major approaches to this problem. The one who concerns on interaction safety and stability, considers teleoperation as a passive system. The rest considers delay manipulation to attain robust performance with limited stability. Obviously, bilateral system is a two-port system just like transformer and gyrator in electrical circuit. There has been tremendous effort to apply gyration for stabilization. However, this paper in different way proposes bilateral teleoperation based on combination of transformer and gyrator analogies. Although with less transparency, this method provides soft sensation on delayed teleoperation. The validity of this method is confirmed through experimental results.

Sensorless cooperation between human and mobile manipulator

This paper presents sensorless cooperation between human and mobile manipulator. In the past, research on cooperation between human and mobile manipulator used force sensor to sense human force. This research aims to develop sensorless cooperation by reaction torque observer instead of force sensor. Utilization of disturbance torque estimation on manipulator and task limitation due to mounted force sensor are considered in this research. Kinematics and dynamical model of mobile manipulator are estimated with Newton-Euler method. Robust acceleration control is established with disturbance observer, reaction torque is estimated from disturbance torque and dynamical model. Cooperative control method based on human force estimation is proposed using impedance control on virtual workspace. Finally, the model and the proposed methods are confirmed through experiment

An iterative approach in pose measurement through hand-eye calibration

Traditionally, the initial pose of a robot manipulator has been done manually. The process must be repeated for each operations and each time a robot is replaced. Hence, pose measurement is needed. In this paper, a camera mounted on the end-effector is employed. Firstly, the position and orientation of camera with respect to the end-effector is solved through AX = XB composition, which is known as hand-eye calibration. However, this paper proposed a modification with an alteration of notation for A and B in prior. An iterative approach is utilized to obtain X. Afterward, multi-stage and one-stage iterative approaches are proposed in pose measurement to eliminate angle displacements on each joint. The first one uses composition as in hand-eye calibration for each joint from the end-effector to robot base. The second one uses one iterative process to solve the entire angle displacements. Simulated data is presented for both results.

Cooperative Mobile Manipulator with Dual Compliance Controllers based on Estimated Torque and Visual Force

This paper proposes dual compliance controllers based on estimated torque and visual force on mobile manipulator to provide cooperativeness. A compliance control provides robot with affinity and adaptability to work in open environment. Generally, compliance control is a control system with trajectory compensation so that an external force may be followed. However, this paper compensates not only external force of physical sensation, but also virtual force of non-physical sensation based on visual information. Here, the robot has compliance with wider sensation. The visual information is provided by highspeed vision sensor. The target object is attached with hexagon pattern of artificial markers to reduce the required image processing time. The distance approximation between the object and the camera is used as visual force not as position or speed reference that commonly used in visual servoing. Later, the visual force adjusts the mobile manipulator command reference. Finally, the experimental result shows the validity of the proposed method

Localizing multiple odor sources in dynamic environment using ranged subgroup PSO with flow of wind based on open dynamic engine library

A new algorithm based on Modified Particle Swarm Optimization (MPSO) which follows a local gradient of the chemical concentration within a plume and follow direction of the wind velocity is investigated. Moreover, the niche or parallel search characteristic is adopted on MPSO to solve the multi-peak and multi-source problem. When using parallel MPSO, subgroup of robot is introduced then each subgroup can locate the odor source. Unfortunately, there is a possibility that more that one subgroup locates one odor sources. This is inefficient because other subgroups locate other source, then we proposed a ranged subgroup method for coping for that problem, then the searching performance will increase. Then ODE (Open Dynamics Engine) library is used for physical modeling of the robot like friction, balancing moment and others. Finally the statistical analysis shows that the new approach is technically sounds.

High-Speed Visual Tracking Based on Artificial Marker and Hexagon Pattern

Tracking a specific object based on visual information, refers to visual tracking. Here, the vision system should be able to distinguish the target object from other objects, especially in complex environment. Obviously, the more complex environment and information required, the more time needed especially for the one with depth and pose extraction. Generally, the hardware delay and the required image processing cause significant problem. Thus, this paper considers high-speed camera utilization within 4ms sampling time. Nevertheless, the hardware should be followed by robust and efficient image processing. Unfortunately, neither edge detection nor geometry extraction is able to be done less than 4ms. Here, having a target object that is commonly certain (specific) object, the artificial marker is introduced. A dark-round marker within adaptive threshold is utilized, so that the system can work in natural environment. In addition, the hexagon pattern is introduced to distinguish the target object from others. This pattern is not only used to resolve object identity, but can also be used to extract the depth and the pose information with total time less than 2.5ms. On the other hand, most visual tracking researches use conditioned environment to attain short delay on vision system with simple image extraction. Finally, the visual tracking based on artificial marker and hexagon pattern is evaluated through 2DOF servo system. The system performance is shown by the experimental results.

Implementation of landmark-based localization on wall-based environment for mobile robot with limited sensor resources

Localization is a well-known main problem in autonomous mobile robot. Here, Extended Kalman Filter (EKF) has received tremendous interest to solve this problem. Solving localization problem using EKF is usually done using numerous sensors, whereas using limited sensor resource with EKF for localization problem remains challenging. Here, this paper proposes EKF implementation for mobile robot localization with limited sensor resource. In order to observe the environment with limited sensors, the feature of the environment is partitioned into several segments which act as landmark. Experimental result shown that the localization results have a small error and are consistent