This paper deals with the trajectory tracking control problem of a planar underactuated tendon-driven truss-like manipulator (UTTM) by using fuzzy logic control methods, including type-1 fuzzy and interval type-2 fuzzy approaches. The UTTM is a novel designed underactuated robot that excels in manipulating in harsh environments due to its tendon-driven parallelogram structure. This unique structure, however, poses challenges for UTTM's trajectory tracking controller design, including underactuation, excessive nonlinearity, parameter uncertainty, and so on. To solve these problems, a fuzzy logic-based approach is proposed. First, the dynamic model of UTTM is transformed into a partially linearized form. Then a type-1 fuzzy controller is designed according to a linear quadratic regulator controller for the linearized system. Then by blurring the membership functions of type-1 fuzzy controllers, an interval type-2 fuzzy logic controller is designed, aiming at dealing with uncertainties. The proposed type-1 and interval type-2 fuzzy logic controllers are validated through simulations, and made comparisons with each other, especially when the system is involved with uncertainties. Simulation results show that the interval type-2 fuzzy-based trajectory tracking controller provides better performance than the type-1 counterpart in terms of tracking accuracy and capacity against uncertainties.

This paper deals with a tracked robot that consists of the proposed crawler module, in which a planetary gear reducer is used as the power transmission device to give two different outputs with just one actuator. This under-actuated system could perform posture control through the interaction between the front and rear modules. On occasion, the posture that the front module is lifted up can make the robot overcome obstacles actively and easily. To find out the controllable postures, the static analysis of the robot has been conducted. In this paper, we provide the control strategy for performing the posture control, and propose the control methods including direct, indirect, and cooperative control to conduct the posture control. Experimental tests show the effectiveness of the control methods.

A two-wheeled robotic rover has advantages to planetary explorations because of its small size and lightweight. Several such rovers can form a cooperating group or combine to be a big multi-wheeled rover or a stable platform by a docking mechanism. This paper presents a novel small robotic rover with two parallel cylinder-conical wheels, which is designed with passive anti-overturn ability and combinability. Mobility system of the robotic rover is introduced, and its ability of passive anti-overturn is discussed based on quasi statics analysis. By dynamical modeling and locomotion simulation, controllability of the rover is studied. Simulation results show its locomotive characteristic