This paper presents a novel approach to increase the amount of visual stimuli in sensor measurements using saliency maps. A saliency map is a combination of normalized feature maps in different channels (i.e. color, intensity) to represent the relative strength of visual stimuli in an image. The total saliency is higher when the camera is looking at a scene with more interesting things in the field of view and vise versa. We employ methods of extremum seeking control to find a camera position that corresponds to local maximum saliency value. We combine the global properties of simplex optimization methods with the local search properties and dynamic response of extremum seeking control to create a novel algorithm that is more likely to find a global maximum than conventional extremum seeking control. Simulations and experiments are presented to show the strength of this approach.

We propose a method for shape classification in rotation manipulation by a multi-fingered robotic hand. The robotic hand has five fingers equipped with tactile sensors. Each tactile sensor can measure the pressure distribution once every 10(ms). Our proposed classification method consists of the following processes: A kurtosis is calculated from the pressure distribution, and it quantifies shape of the current contact surface. By rotating an object and measuring a time-series pressure distribution, the hand obtains a kurtosis pattern. Finally, a degree of similarity is calculated between the kurtosis pattern and a reference pattern through a dynamic programming (DP) matching scheme. This classifies the contact surface shape using thresholds. Laboratory experiments confirm that this method can classify three objects with a high degree of accuracy.

Since a biped robot tends to tip over easily, stable and reliable biped walking is a very important achievement. In this paper, we propose a balance control method based on an off-line planned walking pattern with real-time modification. First, a method of generating a highly stable, smooth walking pattern is presented. Then, a method of real-time modification consisting of body posture control, actual zero moment point control and landing time control based sensor information is proposed. By combining the proposed off-line walking pattern with real-time modification, the biped robot can walk smoothly and adapt to unknown environments. The effectiveness of the proposed method is confirmed by dynamic simulator such as walking on unexpected irregular rough terrain, soft ground and in environments in the presence of disturbances.

Robust implementations of impedance control against modelling errors and disturbances are proposed. Deviation between desired impedance and actual impedance in Cartesian space is defined and modelled as impedance error. Two type robust controllers are designed based on either a high gain feedback eliminating the impedance error or a compensator of the impedance error estimated by disturbance observer. The effectiveness of the proposed controllers is confirmed by numerical simulation and realized on a 2 degree-of-freedom planer direct drive manipulator. estimated by the disturbance observer. Proposed controllers deal with Cartesian space impedance error directly and compensate for this using the usual feedback control, less computational power is needed compared with that based on joint space or the complex control techniques. The effectiveness of the proposed controllers is confirmed by numerical simulation and realized on a 2 degree-of-freedom planer direct drive manipulator.

This paper discusses a design for a robotic finger with the capability of joint torque sensing. The finger joint torque around a drive pulley is proportional to the tension difference on both ends of the pulley. Using a coupling mechanism between tendons, this tension difference can be measured directly, without sensing individual tendon-tensions. The tension differential type torque sensor (TDT sensor) is based on this idea. With a single body of small size and fewer signal lines, the TDT sensor has several advantages in comparison with the conventional approach that obtains the torque by attaching tension sensors at both ends of the drive pulley and feeding sensor signals to a differential circuit.>

A seven degrees of freedom manipulator actuated by a tendon drive system has been developed. In order to reduce the weight and volume of the manipulator, each motor was installed on the base frame and the motor torque was transmitted to each joint through a tendon-pulley system. For the tendon drive mechanism, a coupled drive mechanism was introduced, which actuates the manipulator mechanism by controlling the tension of each tendon in the tendon networks designed with coupled tendon structures. Eight direct-drive motors and tendon-pulleys are for a seven degrees of freedom manipulator. The structure of the manipulator developed is first explained then the tendon tension based control method for the coupled drive manipulator is formulated. Finally, through simple experiments using the manipulator in which the control system was installed, the effectiveness of the proposed structure and the control method are demonstrated.>