Posture control of a three-segmented tracked robot with torque minimization during step climbing

Abstract

In this paper, we present a posture control scheme for step climbing by an in-house developed three-segmented tracked robot, miniUGV. The posture control scheme results in minimum torque at the actuated joints of the segments. Non-linear optimization is carried out offline for progressively decreasing distance of the robot from the step with torque minimization as objective function and force balance, motor torque limits, slippage avoidance and interference avoidance constraints. The resulting angles of the joints are fitted to a third degree polynomial as a function of the robot distance from the step and the step height. It is shown that a single set of polynomial functions is sufficient for climbing steps of all permissible heights and angles of attack of the front segment. The methodology has been verified through simulation followed by implementation on the real robot. As a consequence of this optimization we find that the average current reduced by more than thirty percent, reducing power consumption and confirming the efficacy of the optimization framework.

Geometry‐based flipper motion planning for articulated tracked robots traversing rough terrain in real‐time

“…Among them, Yuan et al (2019Yuan et al ( , 2020 divided the process of crossing a single step into multiple stages, where each stage was modeled, and the control law was designed based on geometric relationships. On the other hand, Singh et al (2014) derived the robot flipper action law that minimizes the flipper torque directly by modeling the kinematics and dynamics of the robot overturning a single-step process. This method can get the optimal process of crossing a particular obstacle, but its limitations are also obvious in that it cannot be adapted to irregular and complex terrain in real environments.…”

Research on Joint Torque Optimization Method of Redundant Space Manipulators with Vibration Suppression

“…At the same time, the expression forms of the generalized coordinates of the system kinetic energy and potential energy have been obtained through the transformation of the corresponding matrix. Then, the dynamic equations of a single flexible body can be obtained and its matrix form is shown as follows: (8) So far, dynamic differential equation has been established. We can draw a conclusion from the derivation of the equations that on account of considering the elastic deformation, the dynamic equations of flexible body become a nonlinear strong coupling differential equation set.…”

“…The research at the present stage mainly focuses on two aspects: on the premise of meeting mission requirements, scientists often take action to minimize joint torque and reduce system energy consumption [5][6][7]. The method proposed by Hollerbach et al [8] and by Osumi et al [9] is typical method of joint torque local optimization and global optimization for redundant manipulator. The former may lead to local optimal solution, while when the dynamic performance is optimized in global method; the control equation will be so complex that the optimization process is very complicated.…”