Sensor design and signal processing for an advanced sonar ring

A conventional sonar ring measures the range to objects based on the first echo and is widely used in indoor mobile robots. In contrast, advanced sonar sensing can produce accurate range and bearing (incidence angle) measurements to multiple targets using multiple receivers and multiple echoes per each receiver at the expense of intensive computation. This paper presents an advanced sonar ring that employs a low receiver sample rate to achieve processing of 48 receiver channels at near real time repetition rates of 11.5 Hz. The sonar ring sensing covers 360 degrees around the robot for specular targets for ranges up to six metres, with simultaneously firing of all its 24 transmitters. Digital Signal Processing (DSP) techniques and interference rejection ideas are applied in this sensor to produce a fast and accurate sonar ring. Seven custom designed DSP boards process the receivers sampled at 250 kHz to maximize the speed of processing and to limit memory requirements. This paper presents the new sensor design, the hardware structure, the software architecture, and signal processing of the advanced sonar ring. Repeatability and accuracy of the measurements are tested to characterize the proposed sensor. Due to the low sample rate of 250 kHz, a problem called cycle hopping can occur. The paper presents a solution to cycle hopping and a new transmit coding based on pulse duration to differentiate neighbouring transmitters in the ring. Experimental data show the effectiveness of the designed sensor in indoor environments.

[1]  Aiguo Ming,et al.  A new method to improve obstacle detection accuracy using simultaneous firing of sonar ring sensors , 1999 .

[2]  Klaus-Werner Jörg,et al.  Mobile robot sonar sensing with pseudo-random codes , 1998, Proceedings. 1998 IEEE International Conference on Robotics and Automation (Cat. No.98CH36146).

[3]  Aiguo Ming,et al.  Fast Mobile Robot Obstacle Detection Using Simultaneous Firing of Sonar Ring Sensors , 1998 .

[4]  A. Ohya,et al.  A fast and accurate sonar-ring sensor for a mobile robot , 1999, Proceedings 1999 IEEE International Conference on Robotics and Automation (Cat. No.99CH36288C).

[5]  Shin'ichi Yuta,et al.  Fast-Bearing Measurement with a Single Ultrasonic Transducer , 1998, Int. J. Robotics Res..

[6]  Lindsay Kleeman,et al.  A sonar sensor for accurate 3D target localisation and classification , 1995, Proceedings of 1995 IEEE International Conference on Robotics and Automation.

[7]  Philip M. Woodward,et al.  Probability and Information Theory with Applications to Radar , 1954 .

[8]  Lindsay Kleeman,et al.  A low sample rate real time advanced sonar ring , 2004 .

[9]  Lindsay Kleeman,et al.  A real time advanced sonar ring with simultaneous firing , 2004, 2004 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) (IEEE Cat. No.04CH37566).

[10]  Maria L. Gini,et al.  Why is it so difficult for a robot to pass through a doorway using ultrasonic sensors? , 1994, Proceedings of the 1994 IEEE International Conference on Robotics and Automation.

[11]  Lindsay Kleeman,et al.  Feature-Based Mapping in Real, Large Scale Environments Using an Ultrasonic Array , 1999, Int. J. Robotics Res..

[12]  Lindsay Kleeman.  Fast and accurate sonar trackers using double pulse coding , 1999, Proceedings 1999 IEEE/RSJ International Conference on Intelligent Robots and Systems. Human and Environment Friendly Robots with High Intelligence and Emotional Quotients (Cat. No.99CH36289).

[13]  Takashi Tsubouchi.  Nowadays trends in map generation for mobile robots , 1996, Proceedings of IEEE/RSJ International Conference on Intelligent Robots and Systems. IROS '96.

[14]  Lindsay Kleeman,et al.  An optimal sonar array for target localization and classification , 1994, Proceedings of the 1994 IEEE International Conference on Robotics and Automation.

[15]  Roman Kuc,et al.  Physically Based Simulation Model for Acoustic Sensor Robot Navigation , 1987, IEEE Transactions on Pattern Analysis and Machine Intelligence.

[16]  Shin'ichi Yuta,et al.  Using one bit wave memory for mobile robots' new sonar-ring sensors , 2000, Smc 2000 conference proceedings. 2000 ieee international conference on systems, man and cybernetics. 'cybernetics evolving to systems, humans, organizations, and their complex interactions' (cat. no.0.

[17]  P. Woodward,et al.  Probability and information theory , 2004 .

[18]  Lindsay Kleeman,et al.  A real time DSP sonar echo processor , 2000, Proceedings. 2000 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2000) (Cat. No.00CH37113).

[19]  Herbert Peremans,et al.  A high-resolution sensor based on tri-aural perception , 1993, IEEE Trans. Robotics Autom..

[20]  Lindsay Kleeman,et al.  Mobile Robot Sonar for Target Localization and Classification , 1995, Int. J. Robotics Res..

[21]  Lindsay Kleeman,et al.  Mobile-Robot Map Building from an Advanced Sonar Array and Accurate Odometry , 1999, Int. J. Robotics Res..

[22]  Yoram Koren,et al.  Error eliminating rapid ultrasonic firing for mobile robot obstacle avoidance , 1995, IEEE Trans. Robotics Autom..