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1 – 10 of 18Junlin Cheng, Peiyu Ma, Qiang Ruan, Yezhuo Li and Qianqian Zhang
The purpose of this paper is to propose an overall deformation rolling mechanism based on double four-link mechanism. The double quadrilateral mobile mechanism (DQMM) has two…
Abstract
Purpose
The purpose of this paper is to propose an overall deformation rolling mechanism based on double four-link mechanism. The double quadrilateral mobile mechanism (DQMM) has two switchable working modes which can be used to traverse different terrains or climb over obstacles.
Design/methodology/approach
The main body of the DQMM is composed of a double four-link mechanism which sharing a public link and two symmetrical steering platforms which placed at both ends of the four-link mechanism. The steering platforms give the DQMM not only steering ability but also reconnaissance ability which can be achieved by carrying sensors such as cameras on steering platforms. By controlling the deformation of the DQMM, it can switch between two working modes (tracked rolling mode and obstacle-climbing mode) to achieve the functions of rolling and obstacle-climbing. Dynamic simulation model was established to verify the feasibility.
Findings
Based on the kinematics analysis and simulation results of the DQMM, its moving function is realized by the tracked rolling mode, and the obstacle-climbing mode is used to climb over obstacles in structured terrains such as continuous stairs. The feasibility of the two working modes is verified on a physical prototype.
Originality/value
The work of this paper is a new exploration of applying “overall closed moving linkages mechanism” to the area of small mobile mechanisms. The adaptability of different terrains and the ability of obstacle-climbing are improved by the combination of multi-modes.
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Zhu Hongbiao, Yueming Liu, Weidong Wang and Zhijiang Du
This paper aims to present a new method to analyze the robot’s obstacle negotiation based on the terramechanics, where the terrain physical parameters, the sinkage and the…
Abstract
Purpose
This paper aims to present a new method to analyze the robot’s obstacle negotiation based on the terramechanics, where the terrain physical parameters, the sinkage and the slippage of the robot are taken into account, to enhance the robot’s trafficability.
Design/methodology/approach
In this paper, terramechanics is used in motion planning for all-terrain obstacle negotiation. First, wheel/track-terrain interaction models are established and used to analyze traction performances in different locomotion modes of the reconfigurable robot. Next, several key steps of obstacle-climbing are reanalyzed and the sinkage, the slippage and the drawbar pull are obtained by the models in these steps. In addition, an obstacle negotiation analysis method on loose soil is proposed. Finally, experiments in different locomotion modes are conducted and the results demonstrate that the model is more suitable for practical applications than the center of gravity (CoG) kinematic model.
Findings
Using the traction performance experimental platform, the relationships between the drawbar pull and the slippage in different locomotion modes are obtained, and then the traction performances are obtained. The experimental results show that the relationships obtained by the models are in good agreement with the measured. The obstacle-climbing experiments are carried out to confirm the availability of the method, and the experimental results demonstrate that the model is more suitable for practical applications than the CoG kinematic model.
Originality/value
Comparing with the results without considering Terramechanics, obstacle-negotiation analysis based on the proposed track-terrain interaction model considering Terramechanics is much more accurate than without considering Terramechanics.
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Jumping robots with coordinated multiple legs have been a hot research subject during the past years because of their excellent abilities in fast moving and obstacle-climbing…
Abstract
Purpose
Jumping robots with coordinated multiple legs have been a hot research subject during the past years because of their excellent abilities in fast moving and obstacle-climbing. However, dynamics of jumping process of these coordinated legged robots are complex because of collisions between coordinated legs and the ground. This paper aims to analyze features of jumping process and to present the kinematic and dynamic models of a novel sole-type quadruped jumping robot with variable coordinated joints.
Design/methodology/approach
A complete jumping period of is divided into several subphases according to contact status of different coordinated legs to the ground. Continuous dynamics and discrete dynamics are established in different subphases. Simulations are performed in MATLAB software and ADAMS environment.
Findings
Comparison between two-set simulated results acquired from ADAMS and MATLAB demonstrates the validity of kinematic and dynamic equations.
Originality/value
The established dynamics establish the foundation of further research in motion planning and controller design of coordinated multiple legs.
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Yangyang Dong, Tongle Zhang, Shaojie Han, Yipan Guo, Bo Zeng, Yongbin Wang and Zijian Zhang
Spherical robot plays an essential role in the field of mobile robot because of its unique shape and omni-directional mobility, especially in the application of planet detection…
Abstract
Purpose
Spherical robot plays an essential role in the field of mobile robot because of its unique shape and omni-directional mobility, especially in the application of planet detection. Although spherical robot has many advantages over leg robot, its obstacle climbing performance is still not satisfactory, that is exactly the motivation of this paper. The purpose of this paper is to propose a high-performance hopping mechanism for spherical robot, which can adapt to different terrain and effectively cross obstacles.
Design/methodology/approach
The hopping system uses torque spring as part of the energy storage mechanism, and converts the kinetic energy of rotation into elastic potential energy with a particularly designed turntable. Moreover, the track of the turntable, based on the Archimedes spiral principle, has the attributes of equidistance and equivelocity that enable better stability of energy storage process.
Findings
Experiments show that the proposed hopping mechanism can make a 250 g spherical robot jump up to 58 cm with the take-off angle of 60°. Finally, the influence of friction and take-off angle on the hopping height and distance of the robot is also analyzed, which provides a prior guidance for optimizing its jumping process.
Originality/value
This paper shows how to easily design a lightweight, compact and embedded spring hopping structure so that a spherical hopping robot with detection ability can be developed.
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Luca Bruzzone and Pietro Fanghella
The aim of the research is the development of a small-scale ground mobile robot for surveillance and inspection; the main design goals are mobility in indoor environments with…
Abstract
Purpose
The aim of the research is the development of a small-scale ground mobile robot for surveillance and inspection; the main design goals are mobility in indoor environments with step climbing ability, pivoting around a vertical axis and without oscillations for stable vision, mobility in unstructured environments, low mechanical and control complexity.
Design/methodology/approach
The proposed hybrid leg-wheel robot is characterized by a main body equipped with two actuated wheels and two praying Mantis rotating legs; a rear frame with two idle wheels is connected to the main body by a vertical revolute joint for steering; a second revolute joint allows the rear axle to roll. The geometrical synthesis of the robot has been performed using a nondimensional approach for generality's sake.
Findings
The experimental campaign on the first prototype confirms the fulfilment of the design objectives; the robot can efficiently walk in unstructured environments realizing a mixed wheeled-legged locomotion.
Practical implications
Thanks to the operative flexibility of Mantis in indoor and outdoor environments, the range of potential applications is wide: surveillance, inspection, monitoring of dangerous locations, intervention in case of terroristic attacks, military tasks.
Originality/value
Different from other robots of similar size, Mantis combines high speed and energetic efficiency, stable vision, capability of climbing over high steps, obstacles and unevenness.
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Giuseppe Quaglia, Luca Bruzzone, Giorgio Bozzini, Riccardo Oderio and Roberto P. Razzoli
The purpose of this paper is to describe the development of a robot for surveillance able to move in structured and unstructured environments and able to overcome obstacles with…
Abstract
Purpose
The purpose of this paper is to describe the development of a robot for surveillance able to move in structured and unstructured environments and able to overcome obstacles with high energetic efficiency.
Design/methodology/approach
The proposed Epi.q‐TG hybrid robot combines wheeled and legged locomotion. It is equipped with four three‐wheeled locomotion units; traction is generated by the two forecarriage units, while the two rear ones have same geometry but are idle. Each front unit is actuated by a single motor with the interposition of an epicyclical gearing, accurately designed in order to suitably switch between wheeled and legged motion. The robot changes locomotion mode from rolling on wheels (advancing mode) to stepping on legs (automatic climbing mode) according to local friction and dynamic conditions.
Findings
The experimental results confirm the design objectives. In advancing mode, the robot behaves like a four‐wheeled vehicle, with high speed and energetic efficiency. In automatic climbing mode, the robot can walk on uneven and soft terrains and overcome steps with remarkable height with respect to its dimensions (up to 84 per cent of the locomotion unit height).
Practical implications
Besides surveillance, Epi.q‐TG can be successfully used in many tasks in which it is useful to combine the advantages of wheeled and legged locomotion, e.g. unmanned inspection of nuclear and chemical sites, minesweeping, and intervention in disaster zones.
Originality/value
The core of the project is the epicyclical mechanism of the locomotion unit, which switches between advancing mode and automatic climbing mode without control action. This solution limits the control and actuation complexity and consequently the robot cost, widening the range of possible applications.
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Antonio Gonzalez Rodriguez, Angel Gonzalez Rodriguez and Pierluigi Rea
The paper aims to present a new mechanical scheme for a leg to be included in legged vehicles that simplifies the control actuations along the stride.
Abstract
Purpose
The paper aims to present a new mechanical scheme for a leg to be included in legged vehicles that simplifies the control actuations along the stride.
Design/methodology/approach
The scheme includes three four‐bar links grouped in two mechanisms. The first one decouples the vertical and horizontal foot movements. The second one produces a constant horizontal foot velocity when the corresponding motor is given a constant speed. A hybrid robot with wheels at the end of the hind legs has been simulated and constructed to validate the leg performance.
Findings
The gait control requires only five commands for the electronic cards to control the leg. Decoupling vertical and horizontal movements allows a more adequate selection of actuators, a reduction of energy consumption, and higher load capacity and robot velocity. Additional mechanical benefits, such as improved robustness and lower inertia, are obtained. The hind legs can also be articulated, allowing the robot to overcome an obstacle and to climb up and down stairs.
Research limitations/implications
A hybrid robot offers greater stability with respect to a legged robot. This way the lateral movement is not a concern, and therefore it has not been tested yet during the walking cycle.
Originality/value
This new scheme obtains a quasi‐Cartesian behaviour for the foot movement that drastically simplifies the control of the walking cycle. Although the decoupling between movements has already been obtained in previous configurations, these follow a pantograph structure and suffer from blocking problems when they are subject to lateral forces. These schemes were suitable for crab‐like gaits. The proposed leg moves according to a mammal‐like gait.
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Chenguang Yang, Lianqing Liu, Zhaojie Ju and Xiaofeng Liu