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.

This paper presents a 5-DoF articulated robot manipulator and proposes a strategy for solving its inverse kinematics. The Denavit – Hartenberg (D-H) parameterization has been used to model the kinematics of the manipulator. As degree of freedom of manipulator increases, the geometrical solution for inverse kinematics becomes difficult; hence an analytical method for the same is presented. Novelty in the method presented is that no approximations of trigonometric functions are used resulting in a theoretical positional accuracy of 10-10mm of the end-effector. The articulated robotic manipulator developed makes use of integrated actuators and rapid prototyping technology enabling easy replication for educational purposes. The robot arm has been used for manipulation tasks in its workspace successfully.

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