Toshihiro Tsumura

A 3-D position and attitude measurement system using laser scanners and corner cubes

This work proposes a new method for measuring the position and attitude of an autonomous land vehicle navigating in a rough terrain. The measurement system proposed here provides precise information on position and heading quickly and continuously. It consists of two laser scanners mounted on the vehicle and corner cubes placed in the environment as landmarks. Each laser scanner rotates a fan-shaped laser beam for detecting the retro-reflections by the corner cubes and measures their azimuth angles. This work presents the principle of measurement and method of positional and attitude estimation. Simulation results are given to show the accuracy of the proposed method.

Path planning for space manipulators using enhanced disturbance map

The motions of the space manipulators cause dynamic disturbances to the spacecraft attitude. This paper proposes a method for planning the manipulator path that reduces such dynamic disturbances using the Enhanced Disturbance Map approach. The Disturbance Map shows the direction of joint movements in the joint space that causes zero disturbance to the spacecraft attitude as well as the magnitude of the maximum disturbance. The proposed method designs small steps of joint movements in the joint space considering hvo directions. One is the direction to realize the desired terminal joint angles and the other is to reduce the disturbances to the spacecraft attitude. The total direction of the joint movement is determined at each step depending both on the magnitude of the disturbances caused by the joint movements and on the distance from the goal. Results of numerical simulations are given for a free-flying robot having a two-link manipulator.

Two-Dimensional Position and Heading Measurement for Vehicle Using Corner Cubes

This paper proposes a method for measuring the position and heading of the vehicle by use of laser and corner cubes. The vehicle has dead reckoning system. The method uses the laser transmitter and receiver on the vehicle and retroreflecting targets on a side of the course. The on-board computer calculates the position and heading from the dead reckoning data when the laser beams hit the corner cube. Each laser beam is set with a certain angle and an offset distance. And the dead reckoning data are stored in memories when the laser beams return to the transmitter. After corner cubes are detected by retroreflected laser beam, position and heading are calculated. The measured data are used for compensating the autonomous position determination.

Measurement of the Position and Heading of a Vehicle Using Corner Cubes on a Road Side

This paper proposes a method for measuring the position and heading of a vehicle moving on a curved course. The method uses laser fan beam transmitters and photo detectors mounted on the vehicle and an array of corner cubes on the course side as retro-reflecting targets. The laser beams have different direction angles and offset distances with each other and, therefore, return to the vehicle at different time according to the position and heading of the vehicle. The on-board computer calculates the position and heading from the time data that indicate the instants of detecting the reflections from the target corner cubes. The measured data are used for correcting the dead reckoning system.

A Method of Position and Heading Measurement Using Corner Cubes on Road Side

This paper proposes a method to measure the position and heading of a vehicle on the road by use of the laser and corner cubes. The method uses the laser transmitter and receiver on the vehicle and a line of the retroreflecting targets on a side of the course. The on-board computer calculates the position and heading from the time data when the laser beams hits the corner cube. Each laser beam is set with a certain angle and an offset distance. Then, the time data when the laser beams return to the transmitter vary according to the position and heading of the moving vehicle. After corner cubes are detected by retroreflected laser beam, position and heading are calculated easily. The measured data will be used as the information for compensation of autonomous position computing system as well as for the alert of sleeping to the driver of the automobile.

PROPOSED POSITION AND HEADING MEASUREMENT SYSTEM OF AUTOMOBILE ON FREEWAY USING LASER BEAMS

This paper presents a variety of methods for obtaining position and heading of automobiles. All of them use laser beam transmitter and receiver units. The first method uses laser transmitter and receiver units on the vehicle and corner cubes set on the side of the roadway. The second method uses laser scanning fan beam units on the vehicle and the corner cubes on the upper side. The third method uses the laser beam transmitter on the side of the roadway and the receivers on the vehicle. Experimental results for three proposed methods using automobiles show that these methods can ba applicable for accurate compensation of errors caused by dead-reckoning positioning method introduced by digital differential odometry.