A versatile locomotion mechanism for amphibious robots: eccentric paddle mechanism

Abstract

Most of recently developed rescue robots can only be deployed to limited attacked regions after tsunami and the floods, due to their limited mobility on complex amphibious terrains. To access such amphibious environments with improved mobility, we propose a novel eccentric paddle mechanism (ePaddle) which has a set of paddles eccentrically placed in a wheel to perform multiple terrestrial, aquatic, and amphibious gaits. One of the advantages of our proposed ePaddle mechanism is its unique locomotion versatility introduced by the eccentric distance between the paddle shaft and the wheel center. We demonstrate this versatility by proposing five typical gaits for traveling on different terrains. For instance, wheeled rolling gait is used to achieve high-speed locomotion on even terrain. Legged gait is applied to travel on the rough terrains. To access the soft terrains where wheels slip and legs sink, a wheel-leg-integrated gait is performed by digging the paddle into the ground. To swim in the water, rotational paddling and oscillating paddling gaits are proposed. For each of these gaits, standard gait sequence is defined and joint parameters are calculated based on kinematics. An ePaddle prototype is then built and tested with the proposed gait sequences. Experimental results verify the design of the ePaddle mechanism as well as its versatile gaits.

Optimized non-reciprocating tripod gait for a hexapod robot with epicyclic-gear-based eccentric paddle mechanism

“…Hence, the relational expression of F Sx , F Sy and F H about θ W and β can be obtained by solving (8). Inspiried by optimal study for traditional legged gait in [13], [14] and [15], we define the optimal state of the supporting paddle as the one that has minimum quadratic sum of F Sx , F Sy and F H expressed in (10).…”

“…Instead of focusing on the design of propulsive mechanism for simple environment, we have proposed a novel hybrid-mechanism-based amphibious propulsive mechanism in our previous works [8]. The latest prototype of this mechanism, called ePaddle-EGM (Eccentric Paddle Mechanism based on the epicyclic gear train) [9] [10], consists of an eccentric paddle and an epicyclic gear train.…”

Design of a high-mobility multi-terrain robot based on eccentric paddle mechanism

“…Based on this idea, concept of the eccentric paddle mechanism (ePaddle), as shown in Fig. 1 , has been proposed firstly in [ 30 ]. The ePaddle mechanism consists of a wheeled shell, a set of rigid paddles, a paddle-shaft, paddle-hinges, and wheel-rim-hinges.…”

“…Five locomotion gaits (as shown in Fig. 2 ) have been proposed in our previous work, three of which are terrestrial gaits, namely the wheeled rolling gait [ 30 ], the legged walking gait [ 31 , 32 ], and the legged-wheeled hybrid gait [ 33 , 34 ]; and two of which are aquatic gaits, named the rotational paddling gait [ 35 ] and the oscillating paddling gait [ 36 , 37 ]. The ability to generate thrusts for underwater propulsion has been observed as well [ 36 , 37 ].…”

“…2 Multi-terrain locomotion modes. An ePaddle-based robot is capable of performing versatile gaits in complex environments [ 30 ] …”