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Wheeled mobile robots are prone to wheel slippage on soft and complex terrains, which affects trajectory tracking accuracy. To improve the trajectory tracking accuracy of robots under such conditions, an adaptive slip compensation controller (ASCC) based on fault‑tolerant control (FTC) is proposed. Firstly, a kinematic model of a four‑wheeled mobile robot (4 WMR) is established by considering wheel slippage rates, and the corresponding trajectory tracking error model is constructed. Then, based on the FTC method, a slippage compensation term is designed. The stability of the ASCC is proven using Lyapunov stability theory, achieving accurate compensation for the velocity error caused by wheel slippage. Finally, experiments under two working conditions are conducted on the 4 WMR. The results show that the designed controller enables the mobile robot to track the desired path under unknown wheel slippage rates, and it exhibits stronger robustness and higher tracking accuracy compared to the conventional controllers. [ABSTRACT FROM AUTHOR]

Ａｃｃｏｒｄｉｎｇ ｔｏ ｔｈｅ ｐｒｉｎｃｉｐｌｅ ｏｆ ａｄａｐｔｉｖｅ ＭＰＣ(ｍｏｄｅｌ ｐｒｅｄｉｃｔｉｖｅ ｃｏｎｔｒｏｌ)ꎬ ａ ｔｒａｊｅｃｔｏｒｙ ｔｒａｃｋｉｎｇ ｃｏｎｔｒｏｌ ｓｔｒａｔｅｇｙ ｆｏｒ ｕｎｍａｎｎｅｄ ｖｅｈｉｃｌｅｓ ｉｓ ｄｅｓｉｇｎｅｄ. Ｂａｓｅｄ ｏｎ ｔｈｅ ｖｅｈｉｃｌｅ ｄｙｎａｍｉｃｓ ｍｏｄｅｌꎬ ｔｈｅ ｔｒａｊｅｃｔｏｒｙ ｔｒａｃｋｉｎｇ ｃｏｎｔｒｏｌｌｅｒ ｉｓ ｅｓｔａｂｌｉｓｈｅｄꎬ ａｎｄ ｔｈｅ ｏｂｊｅｃｔｉｖｅ ｆｕｎｃｔｉｏｎ ａｎｄ ｒｅｌａｔｅｄ ｃｏｎｓｔｒａｉｎｔｓ ａｒｅ ｄｅｓｉｇｎｅｄ. Ｔｈｅ ａｄａｐｔｉｖｅ ＭＰＣ ｃｏｎｔｒｏｌ ａｌｇｏｒｉｔｈｍ ｉｓ ｕｓｅｄ ｆｏｒ ｓｏｌｕｔｉｏｎ. Ａｔ ｅａｃｈ ｃｏｎｔｒｏｌ ｐｏｉｎｔ ｏｆ ｏｐｅｒａｔｉｏｎꎬ ｔｈｅ Ｋａｌｍａｎ ｓｔａｔｅ ｅｓｔｉｍａｔｏｒ ｃｏｒｒｅｌａｔｉｏｎ ｇａｉｎ ｃｏｅｆｆｉｃｉｅｎｔ ｍａｔｒｉｘ ａｎｄ ｔｈｅ ｓｔａｔｅ ｏｆ ｔｈｅ ｃｏｎｔｒｏｌｌｅｒ ａｒｅ ｃｏｎｔｉｎｕｏｕｓｌｙ ｕｐｄａｔｅｄ ｔｏ ａｄａｐｔ ｔｏ ｔｈｅ ｃｕｒｒｅｎｔ ｗｏｒｋｉｎｇ ｅｎｖｉｒｏｎｍｅｎｔ ｏｆ ｔｈｅ ｕｎｍａｎｎｅｄ ｖｅｈｉｃｌｅꎬ ｔｈｅｒｅｂｙ ｃｏｍｐｅｎｓａｔｉｎｇ ｆｏｒ ｔｈｅ ｎｏｎｌｉｎｅａｒｉｔｙ ｏｆ ｔｈｅ ｖｅｈｉｃｌｅ ａｎｄ ｔｈｅ ｅｆｆｅｃｔ ｏｆ ｓｔａｔｅ ｍｅａｓｕｒｅｍｅｎｔ ｎｏｉｓｅ. Ｔｈｅ ｓｉｍｕｌａｔｉｏｎ ｍｏｄｅｌ ｉｓ ｂｕｉｌｔ ｉｎ ＭＡＴＬＡＢ ａｎｄ ｖｅｒｉｆｉｅｄ ｂｙ ｓｉｍｕｌａｔｉｏｎ. Ｉｔ ｉｓ ｃｏｎｃｌｕｄｅｄ ｔｈａｔ ｔｈｅ ａｄａｐｔｉｖｅ ＭＰＣ ｈａｓ ｂｅｔｔｅｒ ｃｏｎｔｒｏｌ ｐｒｅｃｉｓｉｏｎ ａｎｄ ｒｏｂｕｓｔｎｅｓｓ ｆｏｒ ｔｈｅ ｔｒａｊｅｃｔｏｒｙ ｔｒａｃｋｉｎｇ ｏｆ ｕｎｍａｎｎｅｄ ｖｅｈｉｃｌｅｓ. Ｔｈｅ ｅｆｆｅｃｔｉｖｅｎｅｓｓ ｏｆ ｔｈｅ ａｌｇｏｒｉｔｈｍ ｉｎ ｔｈｅ ｔｒａｊｅｃｔｏｒｙ ｔｒａｃｋｉｎｇ ｃｏｎｔｒｏｌ ｌａｙｅｒ ｉｓ ｖｅｒｉｆｉｅｄ. Ｉｎ ａｄｄｉｔｉｏｎꎬ ｉｔ ｐｒｏｖｉｄｅｓ ａ ｒｅｆｅｒｅｎｃｅ ｆｏｒ ｔｈｅ ｒｅｓｅａｒｃｈ ｏｆ ｆｕｔｕｒｅ ｔｒａｊｅｃｔｏｒｙ ｔｒａｃｋｉｎｇ ｃｏｎｔｒｏｌ. [ABSTRACT FROM AUTHOR]

The grasp of the moving capability of a robot is crucial to the motion planning and control of the robot. The moving capability of a hexapod robot which is used over rugged terrains is thus analyzed. First, the hexapod robot platform as well as the system design is introduced.Then, the kinematic models of the hexapod robot leg and the parallel mechanism consisting of the robot torso and each support leg are built respectively. Their workspaces are also analyzed.Finally, the hexapod robot simulation platform with a rugged terrain is built based on Adams and Matlab, and the motion simulation with the hexapod robot is performed. Results show that, through reasonable motion planning that takes account of both the moving capability and terrain profiles, it is possible to effectively enhance the mobility of a hexapod robot over rugged terrains. [ABSTRACT FROM AUTHOR]

Manned lunar rover is handled by an astronaut on the soft lunar terrain. To be familiar with the dynamic properties of manned lunar rover, the astronaut has to be trained and do the imitation experi¬ments on the earth. However, if an imitation vehicle on the earth is used to replicate the linear accelera¬tion running of manned lunar rover on the moon, same driving torques for each vehicle may cause differ¬ent linear accelerations due to the difference between the earth and moon gravities. In terms of above is¬sue , a linear acceleration model of manned lunar rover is established based on the terramechanics and forced-slip theory, and the traction force conditions for the linear acceleration imitation are analyzed. Then an imitation algorithm of driving torque for the wheels of the imitation vehicle is derived to replicate the linear acceleration of the manned lunar rover. The imitation algorithm is verified by using two differ¬ent imitation vehicles with same mass and vertical load as the manned lunar rover on the moon. The cal¬culated results show that the imitation vehicles on the earth driven by the imitation algorithm can produce the same linear acceleration as the manned lunar rover moving on the moon, but the imitation vehicles without using the imitation algorithm cannot produce the same linear acceleration. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

For analyzing the handling deviations of the lunar roving vehicle (LRV) when the astronauts driving it under the earth and lunar gravities, the inverse dynamical system of the LRV was established using the linear quadratic optimal theory, and the trajectory functions with the continuous curvature were deduced under the traditional condition. Then, when the astronauts drove the LRV in the same path under the different gravities, the handling inputs could be solved using the inverse system and trajectory functions. The calculation results show that, for moving in the same path under the different gravities, the astronauts when driving an LRV on the lunar surface need much faster handling speed, bigger handling amplitude, and more frequently handling conversion than driving on the earth. Therefore, it illustrates that the LRV on the moon is much more difficult to handle. [ABSTRACT FROM AUTHOR]