Munsang Kim

Energy-Based Control of a Haptic Device Using Brakes

This paper proposes an energy-based control method of a haptic device with electric brakes. Unsmooth motion is frequently observed in a haptic system using brakes during a wall-following task. Since it is generally known that a haptic system using brakes is passive due to brakes characteristics, its energy behavior has seldom been investigated. However, force distribution at the end effector reveals that the unsmooth motion of a haptic system using brakes represents active behavior of the system in the specific direction. A force control scheme is proposed that computes the gain for smooth motion by considering the energy behavior of a system. Experiments show that smooth wall following is possible with a proposed force control scheme

Visual tracking manipulator with redundancy and its application to robotic wheel assembly

A new wheel assembly automation system is proposed which assembles a wheel into a hub on a car body on a moving hanger in the car manufacturing line. A vision system is used to track the position of the hub on the moving hanger A macro-micro structure is applied to increase a system bandwidth and accuracy to meet an insertion tolerance. The redundancy problem is solved without complicated calculations by assigning different functions that the macro manipulator tracks a velocity error and the micro regulates the position error. Experimental results show that the proposed system can be applied to the wheel assembly task on a moving hanger in the car manufacturing line.

Optimal Design of a New Wheeled Mobile Robot by Kinetic Analysis for the Stair-Climbing States

Many mobile robots have been developed in the various application fields, such as building inspection and security, military reconnaissance, space and undersea exploration, and warehouse services (Muir & Neuman, 1987). Mobile robots are designed with the specific locomotive mechanisms according to the environment of the application field. The various locomotive mechanisms used in mobile robots can be classified into three types: wheeled, tracked, and legged type (Kim, 1999) (Lee et al, 2000). Each locomotion type has its inherent advantages and disadvantages as described below. The wheeled mobile robots (WMRs) weigh less than robots of the other locomotive types and have other inherent advantages, such as high energy efficiency, low noise level, etc (Muir & Neuman, 1987). In comparison with legged mobile robots, the WMRs have a simpler driving part and a plain control strategy, but they have the poor adaptability to the terrain. Tracked mobile robots have the merit of easy off-road travelling. However, they usually have a heavier driving part and need more power for turning motions, in comparison with mobile robots with other locomotive types. Additionally, tracked mobile robots are usually too noisy to be utilized for in-door applications. Legged mobile robots can easily adapt to the unstructured environments, such as off-road environments, but require more actuators to stabilize themselves than mobile robots in the other two categories. As the locomotion mechanisms are complex and need more complicated control algorithms, legged mobile robots have poor mobility on the plane surfaces. Various types of mobile robots that are capable of climbing up stairs have been developed but, until now, most of the mobile robots developed have tracked-type locomotive mechanisms (Kohler et al., 1976) (Maeda et al., 1985) (Yoneda et al., 1997) (Iwamoto & Yamamoto, 1985) (Iwamoto & Yamamoto, 1990). For the purpose of developing a robot capable of traversing the stairs, Estier (Estier et al., 2000) proposed a WMR with three 4-bar linkage mechanisms, by applying the concept of the instantaneous centre of rotation. To explore Mars, Volpe (Volpe et al., 1997) developed a WMR named Rockey 7, which is capable of climbing up steps about 1.5 times as large as the wheel diameter. O pe n A cc es s D at ab as e w w w .ite ch on lin e. co m

Reliable Detection of Sound's Direction for Active Audition

In this paper, we propose reliable detection of sound’s direction for human robot interaction. Compared with previous researches, this system comprises simpler algorithm and a proposed nonlinear amplifier which has advantages to increase a detectible distance of sound signal in spite of simple circuits. Moreover, we propose the new performance index using cross-correlation to make reliable detection of sound’s direction. Also, since this system include a function to detect a period of voice signals, the robot can know when to start finding sound’s direction and performing speech recognition automatically. In order to verify our systems performances, we install the proposed audition system to the prototype robot, called IROBAA (Intelligent ROBot for Active Audition), and describe the experimental results.