Design and implementation of a two-wheel and hopping robot with a linkage mechanism ABSTRACT Wheeled robots exhibit fast and stable motion on a flat road but lack the ability to overcome obstacles and rough terrains. To address this shortage, a two-wheel hopping robot is proposed by combining wheel locomotion and bounce movement. A gear train and a four-bar linkage are employed for jumping. In particular, the take-off angle is dependent on the link length of the four-bar linkage, thus providing versatile flight trajectories. Therefore, the dependency of the hopping performance on the four-bar linkage can be maximized. A four-bar linkage with the same length is used for the specific trajectory and balance control of the inverted pendulum model of the prototype. Dynamics analyses and simulations have been conducted to verify the robot design and its parameters. By jumping tests, the hopping performance is compared with other robots in a quantitative manner. The experimental results show that the wheeled hopping robot has the advantages of light mass and jumping height efficiency. EXISTING SYSTEM : Many researchers implemented a number of wheeled climbing robots, such as the Whegs robot, which can climb obstacles 175% of its wheel radius due to a cockroach-like nominal tripod gait , and IMPASS, which can walk on various terrains, cross over obstacles, and climb up steps by intelligently extending and retracting its spokes. When robots are moving in the uneven terrains, legged locomotion is an ideal alternative to wheels since it allows the use of isolated footholds, the ability to step over obstacles, and the ability to decouple the path of the body from that of the leg . For instance, the self-adaptive robotic leg can passively change its transmission and shape to cross several big obstacles . However, a legged or wheeled robot is not an effective solution to the problem of overcoming high obstacles. PROPOSED SYSTEM : Wheeled robots exhibit fast and stable motion on a flat road but lack the ability to overcome obstacles and rough terrains. To address this shortage, a two-wheel hopping robot is proposed by combining wheel locomotion and bounce movement. A gear train and a four-bar linkage are employed for jumping. In particular, the take-off angle is dependent on the link length of the four-bar linkage, thus providing versatile flight trajectories. Therefore, the dependency of the hopping performance on the four-bar linkage can be maximized. A four-bar linkage with the same length is used for the specific trajectory and balance control of the inverted pendulum model of the prototype. Dynamics analyses and simulations have been conducted to verify the robot design and its parameters. By jumping tests, the hopping performance is compared with other robots in a quantitative manner. Taking advantage of the great deformation of the four-bar linkage, the minimum jumping height of the robot is greater than 117 mm. Compared to “Handle,” which can jump up to 61% of its own height, our robot can jump up to 83% of its height, which is 14 cm. Moreover, the realization of continuous jumping is another highlight, which allows the robot overcome continuous obstacles on the road, thus ensuring the integrity of the entire motion driven by wheels. During the jumping process, the pose of the robot must be maintained in a stable range during landing. CONCLUSION : A novel two-wheeled and hopping robot is proposed. The robot combines the wheel and hopping mechanisms and thus provides a new design idea for the MSR mission in a small-scale area. A four-bar linkage is employed in the robot to generate a hopping motion, and the stable movement of the robot on the road is obtained by wheels. The elastic energy is released by a specially designed gear train. The release process is simulated, and the simulated results indicate that the torsional spring is fully released at the time when the robot takes off. Taking advantage of the great deformation of the four-bar linkage, the minimum jumping height of the robot is greater than 117 mm. Compared to “Handle,” which can jump up to 61% of its own height, our robot can jump up to 83% of its height, which is 14 cm. Moreover, the realization of continuous jumping is another highlight, which allows the robot overcome continuous obstacles on the road, thus ensuring the integrity of the entire motion driven by wheels. During the jumping process, the pose of the robot must be maintained in a stable range during landing. In our future work, to further improve the jumping height of the wheeled hopping robot, other bar linkages will be designed to increase energy efficiency. The second point is to optimize the control algorithm to obtain better robustness and balance performance while jumping and landing.

by | Oct 17, 2018 | ieee project

  Design and implementation of a two-wheel and hopping robot with a linkage mechanism   ABSTRACT Wheeled robots exhibit fast and stable motion on a flat road but lack the ability to overcome obstacles and rough terrains. To address this shortage, a two-wheel...