Dynamical Modeling and Control of Modular Snake Robots With Series Elastic Actuators for Pedal Wave Locomotion on Uneven Terrain

Abstract

This paper introduces the equations of motion of modular 2D snake robots moving in vertical plane employing Series Elastic Actuators (SEAs). The kinematics of such 2D modular snake robot is presented in an efficient matrix form and Euler–Lagrange equations are constructed to model the robot. Moreover, using a spring-damper contact model, external contact forces, necessary for modeling pedal wave motion (undulation in the vertical plane) are taken into account, which unlike existing methods can be used to model the effect of multiple contact points. Using such a contact model, pedal wave motion of the robot is simulated and the torque signal measured by the elastic element from the simulation and experimentation are used to show the validity of the model. Moreover, pedal wave locomotion of such robot on uneven terrain is also modeled and an adaptive controller based on torque feedback in gait parameter's space with optimized control gain is proposed. The simulation and experimentation results showed the efficacy of the proposed controller as the robot successfully climbed over a stair-type obstacle without any prior knowledge about its location with at least 24.8% higher speed compared with non-adaptive motion.

Dynamic Modeling Method of Multibody System of 6-DOF Robot Based on Screw Theory

“…The proposed algorithm can be programmed with symbolic and inertial parameters. Koopaee et al [4] developed a two-dimensional modular snake-like robot, established the dynamic model of the robot by the Euler-Lagrange equation, and proposed an adaptive controller based on torque feedback in the gait parameter space and optimized the control gain. The effectiveness of the model and controller is verified by simulation and experiment.…”

A Survey on Snake Robot Locomotion

“…The Newton-Euler formula is the most appropriate method to obtain the torque required for the desired motion. At the same time, the Lagrangian formula describes the time evolution of the system's generalized coordinates [48]. Newton-Euler formula was used in conjunction with the set-valued force law for deriving a non-smooth 2D model [7], [49], [50].…”

A differentiable actuator extends potential configurations of modular robots

“…Bionic approaches are widely used in the design of modular robots, including footed robots [1][2][3][4][5], continuous robots [6][7][8][9][10][11][12][13][14][15][16][17], which mimic biological macrostructures, and particle robots [18][19][20][21][22][23][24]. The functionality of the modular robot depends on its configuration and size.…”