mobility performance evaluation of planetary rover with simi(6)

时间：2026-01-22

月球车珍贵资料——来自美国

difficult to produce the model with an exact size, because of 1/6 Model is extremely small and light weight. Thus, we proposed to use 1/3 Model, which is easy to produce and to treat relatively. We carried out low-gravity flight experiment with 1/3 Model to fill similarity laws. In this time, assuming that similarity law is realized under every gravity environment, we have made relative evaluation on a degree of mobility by the difference of mobility systems. PEGASUS has high mobility, with very simple mechanism, and PEGASUS is able to successfully move better than 4WD by similarity model experiment under 1/2G gravity. Although a part of result in the mobility performance is opposite between PEGASUS and 4WD, we think it's due to the character of the low-gravity flight experiment and the mechanical problems of the models. In the case of running on the sandy slope, we guess that the horizontal power on the basis of sandy slope increases as the gradient becomes large, and it causes increase of the slip ratio. In the result, the experimental model must have reached to be stacked.

On the other hand, we could check a variety of influence on the degree of mobility, which the difference of gravitational acceleration does. For example, the model bob up and down at the moment its front wheels get in touch with the step to climb over in microgravity, and the slip ratio of the wheel changes by the size of gravitational acceleration, etc. As far as the slip ratio concerned, we guess that the slip ratio increases as a gravitational acceleration increases, because the experimental model gains weight in the same gradient as a gravitational acceleration increases.

We have checked that there was a difference in a degree of mobility between PEGASUS and 4WD in the experiment under 1/2G gravity. But we don't know whether similarity law is realized also under other various gravities. In the future, we'll carry out an experiment under 1G gravity with another 1/6 model rover. We'll reconfirm that PEGASUS was high degree of mobility in comparing with low-gravity flight experiment and look into similarity law. Also, we'll develop the new mobility system by carrying out the experiment with the model of various patterns.

Acknowledgments Mr. Hiroshi Kanamori of NASDA taught in using a simi-larity law. A soil called "simulant" for an experiment was contributed from Mr. Shigeru Aoki of NASDA. Brushless DC motor driver was contributed from Advanced Circuit Technologies (ACT) Inc. We have carried out a flight

experiment by collaboration with Diamond Air Service (DAS) Inc.

Reference

[1] C.R.Weisbin, very, G.Rodriguez: "Robotics Technology for Planetary

Missions into 21st Century", Proc. of International Symposium on Artificial Intelligence, Robotics and Automation for Space (i-SAIRAS'97), July, 1997.

[2] James D. Burke: "Past US Studies and Development for Planetary Rovers",

Proc. of International Symposium on Planetary Mobile Vehicles, Toulouse, 1992.

[3] A.L. Kemurdajian: "PLANET ROVER AS AN OBJECT OF THE

ENGINEERING DESIGN WORK", Proc. of the IEEE Int. Conf. on Robotics and Automation, pp.140-145, 1998.

[4] R.Simmons, L.Henricksen, L.Chrisman and G.Whelan: "Obstacle

Avoidance and Safeguarding for a Lunar Rover", Pro. of AIAA Forum on Advanced Developments in Space Robotics, 1996.

[5] T.Kubota, Y.Kuroda, Y.Kunii, I.Nakatani: "Micro Planetary Rover

'Micro5'", Proc. of i-SAIRAS'99, June, 1999.

[6] Richard Volpe, J. Balaram, Timothy Ohm, and Robert Ivlev: "The Rocky7

Mars Rover Prototype", Proc. of IEEE/RSJ International Conference on Intelligent Robots and Systems, November, 1996.

[7] Samad Hayati, Richard Volpe, Paul Backes, J. Balaram, Richard Welch,

Robert Ivlev, Gregory Tharp, Steve Peters, Tim Ohm, Richard Petras, and Sharon Laubach: "The Rocky7 Rover: A Mars Sciencecraft Prototype", Proc. of IEEE ICRA'97, THAI2-2, 1997

[8] L.Matthies, E. Gat, R.Harrison, B. Wilcox, R. Volpe, and T. Litwin: "Mars

Microrover Navigation: Performance Evaluation and Enhancement", Autonomous Robotics Journal, vol.2, no.4, 1995.

[9] Henry W. Stone: "Mars Pathfinder Microrover-a Small, Low-Cost, Low-Power Spacecraft", Proc. of AIAA Forum on Advanced Developments in Space Robotics, 1996.

[10] T.Kubota: "Mars Pathfinder", Proc. of Journal of the Robotics Society of

Japan (JRSJ), vol.15, no.7, pp.986-992, 1997. (in Japanese)

[11] I.Nakatani, T.Kubota, H.Katoh, Y.Kuroda, T.Adachi, H.Saito, T.Iijima,

T.Takano: "A Long Distance Moving Test for Planetary Rover", Proc. of Intelligent Robots and System (IROS'97), September, 1997.

[12] T.Kubota, I.Nakatani: "Autonomous Behavior Control Scheme for Lunar

or Planetary Rover", Proc. of 5th Workshop on Astrodynamics and Flight Mechanics, pp.334-339, 1995.

[13] W.Whittaker, D.Bapna, Mark W.Maimone, E.Rollins: "Atacama Desert

Trek: A Planetary Analog Field Experiment", Proc. of i-SAIRAS'97, July, 1997.

[14] D.Wettergreen, D.Bapna, M.Maimone and H.Thomas: "Developing

Nomad for Robotics Exploration of the Atacama Desert", Robotics and Autonomous Systems, vol.26, no.2-3, pp.127-148, 1999

[15] Y.Kuroda, K.Kondo, K,Miyazawa, T.Kubota, I.Nakatani: "Development

of a Combination of Mother/Daugther Planetary Rovers", Proc. of ROBOMEC'97, pp.357-358, 1997. (in Japanese)