Design and Experimental Evaluation of a Single-Actuator Continuous Hopping Robot Using the Geared Symmetric Multi-Bar Mechanism

A Small-Scale Hopper Design Using a Power Spring-Based Linear Actuator

Hopping locomotion has the potential to enable small-scale robots to maneuver lands quickly while overcoming obstacles bigger than themselves. To make this possible, in this paper, we propose a novel design of a high-power linear actuator for a small-scale hopper. The key design principle of the linear actuator is to use a power spring and an active clutch. The power spring provides a near constant torque along the wide range of output displacement. The active clutch controls the moving direction and operation timing of the linear actuator, which enables the hopper to take off at the right timing. As a result, the hopper has a size of 143 mm, a mass of 45.9 g, and hops up to 0.58 m.

CLOVER Robot: A Minimally Actuated Jumping Robotic Platform

Robots have been critical instruments to exploration of extreme environments by providing access to environments beyond human limitations. Jumping robot concepts are attractive solutions to negotiate complex and cluttered terrain. However, among the engineering challenges that need to be addressed to enable sustained operation of jumping robot concepts in extreme environments, the reduction of mechanical failure modes is one of the most fundamental. This study sets out to develop a jumping robot design, with a focus on a minimal actuation to support reduced mechanism maintenance and thus limit the number of mechanical failure modes. We present the synthesis of a Sarrus-style linkage to constrain the system to a single translational degree of freedom thus removing the need for synchronising gears, which exhibit high failure rates in dusty environments. We have restricted the present research to vertical solid jumps to assess the performance of the fundamental main-drive linkage. A laboratory demonstrator assists the transfer of theoretical concepts and approaches to practical implementation. The laboratory demonstrator performs jumps with 63% potential-to-kinetic energy conversion efficiency, with a theoretical maximum of 73%. Satisfactory operation opens up design optimisation and directional jump capability towards the development of a jumping robotic platform for extreme environments exploration.

Dynamic Modeling and Control of a Novel One-Legged Hopping Robot

In this article, a novel mechanism for planar one-legged hopping robots is proposed. The robot consists of a flat foot which is pinned to the leg and a reciprocating mass which is connected to the leg via a prismatic joint. The proposed mechanism performs the hopping by transferring linear momentum between the reciprocating mass and its main body. The nonlinear equations of the motion of the robot are derived using the Euler–Lagrange equations. To accomplish a stable jump, appropriate trajectories have been planned. To guarantee a stable response for this nonlinear system, a sliding-mode controller is implemented. The performance of the hopping robot is investigated through numerical simulations. The results confirm the stability of the hopping robot through the jump cycle on a flat surface and in climbing up and down ramp and stairs.