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Africa
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Terrestrial Locomotion
Published in Malcolm S. Gordon, Reinhard Blickhan, John O. Dabiri, John J. Videler, Animal Locomotion, 2017
This short review may give the reader an idea of the wide range of current developments in the area of bioinspired terrestrial robots. Taking resort to natural examples has been and will be a successful strategy. By building such machines, we are able to test our understanding of the biological systems (e.g., Long 2012). In the robots listed above, there is a trend toward system compliance. The compliance may be attributed to corresponding materials (e.g., RHex) or largely to control (e.g., BigDog). Our understanding on how such properties lead to “modes” of locomotion will improve and inspire engineers. It seems that the tuning of material properties to the task without losing versatility is one of the key issues where we still can learn from nature. Hereby, details such as geometry and arrangement will reveal their physical meaning. We only touched the issue of the muscular drive. As such, a drive incorporates compliance and damping identifying technical drives with similar properties will be an important area of future research. We are just beginning to reveal how the intelligent organization of muscle–skeletal systems facilitates control. This includes the adjusted implementation of materials such as the muscular tissue. It is highly probable that shock absorption by wobbling tissues that come for free in animals will also find its way in the construction of fast machines. And for large machines, we may admit that protecting the lightweight segments with a viscoelastic damping coat may be suitable. We will probably not copy the multipurpose muscle tissue, but use several translations to mimic the different functions. Animal joints may also serve as examples. We are able to make decent copies for joint replacement. However, there may be much more than the simple degree of freedom and load bearing to be worthwhile to transfer into robotics. Biomechanists developing forward models are aware of the significance to implement proper passive joint properties. It may well be that in future plastic skeletons and rubber drives with embedded flexible electronics may dominate machines, and technical runners may look and perform more and more like their animal model. The direction of development will strongly depend on future tasks devoted to such machines. Currently, tasks such as exploration, transport, and support seem to be within reach. With engineers becoming more familiar with the concepts, their fantasy may open realms so far unexplored by their animal precursors and spur technical evolution.
Optimal design of a stair-climbing mobile robot with flip mechanism
Published in Advanced Robotics, 2018
Pengzhan Liu, Jianzhong Wang, Xin Wang, Peng Zhao
Hybrid wheel-leg (wheg) robots include the popular RHex hexapod [5] and a number of robots with alternate wheg designs, including DEKA iBOT [6], Quattroped [7], etc. They have capability to step across barrier and can move fast, but they are can only climb stairs with low pitch angle, and they are large in size and weight.
Expanding scissor-based UGV for large obstacles climbing
Published in Mechanics Based Design of Structures and Machines, 2019
In the case of large obstacles, the control methods eliminate a broad range of climbing issues (Kim et al., 2016; Naderi et al., 2017). However, implementing some stability methods such as ZMP especially in humanoid robots can reduce the danger of overturning during obstacle or stair climbing (Jatsun et al., 2016). In the case of autonomous rovers facing medium size obstacles, the contact detection and slip reduction algorithms can solve this issue. The slip reduction algorithms estimate dynamics of UGV platforms at the current moment and calculate the appropriate torque of motors so that the slip is minimized (Xu et al., 2016; Kobayashi et al., 2018; Siravuru et al., 2017). Moreover, other methods consider the slip ratio as the base of slip control using high-resolution sensors (Enmei et al., 2017; Gao et al., 2017). Some investigations have demonstrated the influence of deep learning in the performance of slip reduction algorithms (Namba and Yamada, 2017). Notwithstanding the control-based efforts to reduce the danger of rover slip when facing medium obstacles, they have not been exploited frequently for large obstacles such as big rocks and cliffs. In this regard, a high mobility robot vehicle Go-For with wheels-on-legs configuration was developed to climb vertical steps up of height 70% of the maximum vehicle dimension (Wilcox, 1992). A big-wheel-inflatable rover was designed to overcome large rocks on Martian ground (Fiorini, 2000). Moreover, the rover platform Sojourner has been designed as a small-sized vehicle empowered by a new suspension system to overcome the small and medium size obstacles (Bickler et al., 2001). ATHLETE was fabricated as a vehicle specified for moving over extreme lands by means of six legs equipped with independent wheels (Wilcox et al., 2007). However, despite of all ATHLETE adequate abilities, its platform includes expensive limbs and various degrees of freedom besides high power consumption. As another effort to challenge rough terrains, SAFIR rover, which refers to a rescue robot designed for assistance, was another rover designed for hazardous missions (Edlinger et al., 2016). The above-mentioned efforts include mainly UGVs with fixed-geometry platforms in which their structures are not deployable and the geometric parameters are constant (Michaud et al., 2002). Some multimode mobile rovers such as Rhex, a wheeled-leg robot, (Saranli et al., 2001) and (Schwarz et al., 2016) have been developed for rough environments from 2010 through 2017. These robots are able to pass some obstacles due to additional legs and limbs. One of the disadvantages of these platforms is typically the number of degrees of freedom.