Takao Kakizaki

Dynamic Parameter Identification Of An Industrial Robot And Its Application To Trajectory Controls

An experimental study is presented on the dynamic parameter identification of a typical industrial robotic manipulator, PUMA260. First, parameter coef- ficient equations are derived from a linearized equation of the robot to clarify its base parameters and a mo- tion planning strategy is proposed for accurate identifi- cation. Next, the effects of manipulator configuration, angular velocity and angular acceleration on the iden- tification are experimentally investigated and desirable motion conditions are determined. Moreover, the fea- sibility of a reduced dynamic model consisting of pa- rameters that dominantly contribute to joint torques is studied. Finally, the proposed parameter identification technique is validated by manipulator trajectory control experiments.

A multimodal teaching advisor for sensor-enhanced robotic systems in manufacturing

Abstract A multimodal teaching advisor (MTA) has been developed for sensor-enhanced robotic systems used in manufacturing. The MTA utilizes the work-site operator’s know-how and robotic-systems information, including that from sensors, in a complementary manner. This system integrates information from various sources to carry out robotic tasks and presents this information through user interfaces that are easily understood by the operator. That is, the system integrates task specifications including tolerances, system constraints, sensory information, and operator- and robot-related information. The synthesized information is then presented in realtime to the operator at the work-site through a mobile multimodal interface. Experimental results show that this system can significantly improve total robotic system performance by ensuring a high-quality teaching task.

Task world reality for human and robot system. A multimodal teaching advisor and its implementation

The concept of task world reality (TWR) for a sensor-based robot system and human operator at the work-site is proposed. Based on the TWR concept, a multimodal teaching advisor (MTA) which utilizes the work-site human operators know-how and sensory information in a complementary manner has been developed. This system integrates task specifications, system constraints including their tolerances, sensing information, and operator- and robot-related information. MTA provides both graphical and audio user interfaces using a spatial human trader in order to support an advanced teaching environment for a work-site operator. A complicated spatial path tracking task is taken as a typical case study. Experimental results show that not only the human operators teaching load but also the task quality are greatly improved by MTA.

A multi-modal teaching-advisory system using complementary operator and sensor information

A multimodal teaching-advisory system for sensor-based robot systems is presented that uses complementary information obtained from the operator and sensors. We propose a new framework for on-site robot teaching systems that takes account of the characteristics of humans and sensors. This framework enables the teaching system to integrate a variety of robot task constraints, task specifications, their tolerances as defined by the operator, and sensing information acquired by the sensors in a complementary manner. The system synthesizes all of this information into a form that is easily understood by the operator. Finally, the synthesized information is presented to the operator as multimodal information. By combining this advisory information with the operators own information, the desired robot teaching commands can be generated. This system can significantly improve total robot system performance by ensuring high-quality teaching.

Post-Tsunami Evacuation Simulation Using 3D Kinematic Digital Human Models and Experimental Verification

A post-tsunami evacuation simulation using 3D kinematic digital human models (KDHs) and its experimental verification are addressed in the present study. Methods for carrying or assisting (transporting) injured people were experimentally investigated and the results were used for KDH data calibration to increase the accuracy of the simulations. It was found that, on flat ground, both the transit speed and the amount of time spent on intermittent rests were strongly affected by the load on the transporters. During ascent of stairways, the transit speed depended on the type of carry method being used, and decreased in the order saddleback carry, two-person arm carry and slightly injured walking. Several KDH evacuee motion primitives were developed for stairway ascent to a tsunami evacuation tower. The simulation results show that the evacuation time was affected by the number of evacuees and the congestion due to the transportation of injured people. The developed simulation techniques can be effectively utilized in the planning of tsunami tower evacuation and predicting related crowd behavior.Copyright

Evaluating User Interface of Multimodal Teaching Advisor Implemented on a Wearable Personal Computer

A multimodal teaching advisor (MTA) that utilizes the work-site operators know-how and robotic-system information, including that obtained from sensors, in a complementary manner has been enhanced and implemented on a wearable personal computer (WPC) for use with sensor-enhanced robotic systems used in manufacturing. The MTAs software was enhanced to acquire and monitor sensory and robot-motion data. The MTA presents support information to the operator via graphical and speech user interfaces in the WPC. Experimental results for a spatial-path-tracking task performed using a laser range finder showed that the MTAs operation was greatly improved. In particular, the simultaneous provision of support information via both the graphical and speech interfaces shortened the time taken for the operator to teach a robot using a teaching pendant.

The Effects of Groundwater Flow on Vertical-Borehole Ground Source Heat Pump Systems

Heat advection by groundwater flow is known to improve the performance of ground heat exchangers (GHEs), but the effect of groundwater advection on performance is not yet fully understood. This study examined how parameters related to groundwater flow, such as aquifer thickness, porosity, lithology, and groundwater flow velocity, affect the performance of a borehole GHE. Under the thin-aquifer condition (10 m, or 10% of the entire GHE length in this study), groundwater flow velocity had the greatest effect on heat flux. With a groundwater flow velocity of at least 10−4 m/s through a low-porosity aquifer filled with gravel with high thermal conductivity, the heat flux of a GHE was as much as 60% higher than that of a non-aquifer GHE. If the aquifer is as thick as 50 m (50% of the entire GHE length), the high thermal conductivity of gravel doubled the heat flux of the GHE with a groundwater flow velocity of at least 10−5 m/s. Thus, not only groundwater flow velocity, but also aquifer thickness and thermal conductivity were important factors. However, groundwater seldom flows at such high velocities, and porosity, gravel size, and aquifer thickness vary regionally. Thus, in the design of ground source heat pump systems, it is not appropriate to assume a large groundwater effect.Copyright

Numerical Solution of a Ground Source Heat Pump System Using Foundation Piles

A ground source heat pump (GSHP) system has higher cooling and heating performances than an air source heat pump system, so the GSHP system has attracted attention in the cold regions. Particularly after the 2011 earthquake off the Pacific coast of Tohoku, which damaged nuclear power plants, the GSHP utilizing renewable energy, has become attractive in heating system in the Tohoku region. However, it is necessary to install wells to collect ground source heat, and so, together with the cost of the heat pump itself, the installation cost is a barrier to widespread adoption of this technology in Japan.On the other hand, due to poor subsoil, foundation piles are often required in the construction of buildings in Japan. By using foundation piles as heat exchangers, which are commonly used in residential construction, the cost of using GSHP systems in houses may be reduced. However, since the placement of the piles depends on the floor layout of the residence, that is arbitrary sequence. Moreover, an arbitrary floor layout requires a complicated multi-dimensional numerical analysis to design the GSHP, and the analysis is burdensome for general designers. Therefore, the use of the model unit of the two-dimensional cylindrical heat exchange well is proposed. The use of this model, which includes an unused volume of soil, reduces the analysis burden for general design tools.On experience, the arrangement rate is 4 m2 per pile, and the well separation is narrow. And the foundation piles will form a group. So thermal interference between heat exchanger wells might be working hard. In addition, the foundation piles are very short, compared to the traditional borehole depth of 50 to 100 m. Therefore, the thermal performance of the well may degrade compared to that of the traditional GSHP system, although the initial costs are less. Therefore, we examined a GSHP system with heat exchanger piles by using the heat exchange well unit model for residences in the Tohoku region.As a result, the two-dimensional analysis and more is needed to predict the thermal performances of the heat exchanger piles so that the effect of the pitch of the heat exchange wells on the heat transfer in the axial direction will be large. In cold climates, the heating demand is large and, in the summer, the amount of waste heat to the ground is small, so a large amount of heat penetration into the ground from the atmospheric air is important for continuous GSHP operation in the Tohoku region, and in Fukushima Prefecture in particular.Copyright

Sensor-enhanced robotic cell collaboration using shared task error information

A multiple-sensor-enhanced robot collaboration system has been developed for manufacturing applications, The system consists of basic robot modules, such as for locating and trading. These modules have laser range finders and perform hybrid manufacturing tasks by working together as an advanced robotic cell. A hybrid task with uncertainties can be described by the task velocity and task error derived from the sensory and motion information on the robot modules. The modules send their bask error and waiting time to each other via a collaboration network. They also modify their given motion sets in real time based on fuzzy rules in order to improve the accuracy and efficiency of the system. An experimental study of multi-station welding showed that this collaboration results in a satisfactory trade-off between accuracy and efficiency.

A spatial position tracker for work-site teaching of sensor-enhanced robotic systems

A spatial position tracker (SPT) for the human operator that performs robotic teaching at a work-site coexisting with a sensor-enhanced robot system is presented. The SPT measures the operators position in real time by stereo processing of images from two CCD cameras with infrared filters and the operators orientation, using a three-dimensional gyro. It enables the work-site operator to utilize augmented reality to understand the necessary task world information, including the sensor and end-effectors relative position and orientation without any special skills. In this paper, we describe the system configuration, discuss the detection accuracy, and present results for applying it to a multimodal teaching advisor currently being developed.