Design and dynamic analysis of jumping wheel-legged robot in complex terrain environment

Abstract

Wheel-legged robots have fast and stable motion characteristics on flat roads, but there are the problems of poor balance ability and low movement level in special terrains such as rough roads. In this paper, a new type of wheel-legged robot with parallel four-bar mechanism is proposed, and the linear quadratic regulator (LQR) controller and fuzzy proportion differentiation (PD) jumping controller are designed and developed to achieve stable motion so that the robot has the ability to jump over obstacles and adapt to rough terrain. The amount of energy released by the parallel four-bar linkage mechanism changes with the change of the link angle, and the height of the jump trajectory changes accordingly, which improves the robot’s ability to overcome obstacles facing vertical obstacles. Simulations and real scene tests are performed in different terrain environments to verify obstacle crossing capabilities. The simulation results show that, in the pothole terrain, the maximum height error of the two hip joint motors is 2 mm for the obstacle surmounting method of the adaptive retractable wheel-legs; in the process of single leg obstacle surmounting, the maximum height error of the hip joint motors is only 6.6 mm. The comparison of simulation data and real scene experimental results shows that the robot has better robustness in moving under complex terrains.

Evolution, Design, and Future Trajectories on Bipedal Wheel-legged Robot: A Comprehensive Review

“…Moreover, they are deployed by military forces to conduct reconnaissance in rugged landscapes such as reported in [33]. On the other hand, in manufacturing industries, wheel-legged robot agility has been leveraged to efficiently manage the materials within intricate industrial settings such as reported in [34]. At the forefront of this groundbreaking field stands Swiss-Mile, a creation of ETH Zurich's Robotic Systems Lab.…”

“…BWL robots, which combine the agility of legged robots with the mobility of wheeled counterparts, are reshaping the landscape of mobile assistive systems. These robots feature three primary locomotion modes: bipedal walking, bipedal skiing, and rolling, enabling both stable walking and rapid rolling [4]- [7]. Their ability to seamlessly switch between these modes is crucial for adapting to diverse environments [6].…”

“…In contrast to traditional wheeled robots, these robotic systems have a relatively high center of gravity, making them susceptible to balance disruptions, especially when navigating uneven terrains. These tendencies can result in undesired outcomes like tilting or toppling [7], [10], [11]. Transition phases, where the robot transitions from wheeled to legged motion and vice versa, are exceptionally delicate junctures.…”

“…Therefore, ensuring flawless coordination between the robot's limbs and wheel mechanisms during these transitions is imperative [12]. Although they exhibit commendable performance on flat landscapes, their design sometimes hinders unhindered movement on more challenging terrains [7]. Tailoring control strategies to enable seamless mode transitions based on terrain intricacies is crucial [13].…”

A Fuzzy LQR PID Control for a Two-Legged Wheel Robot with Uncertainties and Variant Height

“…In [42], a cascade PID controller was proposed for a bipedal leg-wheeled robot to guarantee the stabilization and driving. In [49], LQR controller and fuzzy PD controller were investigated on a new type of wheel legged robot with parallel four-bar mechanism for stable movement and jumping over obstacles.…”