Structural Design and Crawling Pattern Generator of a Planar Quadruped Robot for High-Payload Locomotion

Abstract

Load capacity is an important index to reflect the practicability of legged robots. Existing research into quadruped robots has not analyzed their load performance in terms of their structural design and control method from a systematic point of view. This paper proposes a structural design method and crawling pattern generator for a planar quadruped robot that can realize high-payload locomotion. First, the functions required to evaluate the leg’s load capacity are established, and quantitative comparative analyses of the candidates are performed to select the leg structure with the best load capacity. We also propose a highly integrated design method for a driver module to improve the robot’s load capacity. Second, in order to realize stable load locomotion, a novel crawling pattern generator based on trunk swaying is proposed which can realize lateral center of mass (CoM) movement by adjusting the leg lengths on both sides to change the CoM projection in the trunk width direction. Finally, loaded crawling simulations and experiments performed with our self-developed quadruped robot show that stable crawling with load ratios exceeding 66% can be realized, thus verifying the effectiveness and superiority of the proposed method.

Controllable Height Hopping of a Parallel Legged Robot

“…The details of the structure comparison and jumping simulation results are shown in Figures 3 and 4. More comparative analyses of parallel and serial structure of legged robot are presented in another paper [26]. Previous research has shown that the ideal mass ratio of the leg involves a large trunk mass and a lower leg mass [27].…”

Frequency Spectra Analysis of Drawbar Pulls Generated by Special Driving Wheels Improving Tractive Performance

“…The design of the spike tires (Figure 2) was proposed with four spike elements (9), which consist of a support rod (1) and two spikes (2). Each element is placed in the tire groove (6) made in the tire tread pattern.…”

“…The drawbar pulls of the test tractor with standard tires, spike tires, and blade wheels with low and high loads are shown in Figure 6. The RMS drawbar pull values of the tractor with different driving wheels with low and high loads, calculated according to Equation (2), are presented in Table 2. The levels of the drawbar RMS values are shown as straight lines in Figure 5.…”

“…Fast Fourier transformation (FFT) is widely used for signal analysis for many applications in engineering, science, mathematics, etc. Several mechanical features of rotary mechanisms change with speed [ 2 , 3 ]. The FFT analysis of the frequency spectrum helps to identify the characteristic frequency components because no obvious peaks appear in the spectrum.…”

Suboptimal Omnidirectional Wheel Design and Implementation

“…On the one hand, the automatic development of such cooperative tasks requires the use of human compatible devices in order to avoid collisions or actions that can harm people, mainly using laser range sensors [ 1 , 2 ], depth cameras [ 3 , 4 ], or surveillance systems [ 5 ]. On the other hand, the automatic development of cooperative tasks requires the use of human compatible devices moving like people in common spaces designed for people, mainly using legs [ 6 ], omnidirectional wheels [ 7 ], or hybrid legs [ 8 , 9 ].…”