Locomotive Robotics

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Design of Locomotive Robots

A. Cheetaroid-I series
Cheetaroid-I series

Cheetaroid-I Carrier, which has been developed for load-carrying applications.
B. Cheetaroid-II series
For the easiness in control and the minimal weight of the overall robot system, all the four legs of Cheetaroid-II robots are connected by mechanical links and actuated by only one actuator. In addition to the actuated leg joints, the proposed robot also has compliant feet for enhancing gait efficiency. The parameters of the mechanical link system are selected by an optimization process such that the simulated link motion is close to the leg motions of the animal. The actuator, however, is subjected to large disturbance forces due to the whole body actuation. Therefore, a set of a worm-gear and a worm-wheel is used as a transmission system for improved mechanical impedance and disturbance rejection performance.

Control of Locomotive Robots

A. Gait pattern generation and locomotion control
B. Vibration suppression of a robotic leg

Landing without vibration suppression

Landing with vibration suppression
C. Realization of Spring Loaded Inverted Pendulum Dynamics with a Two-link Manipulator Based on the Bio-inspired Coordinate System
Robotic manipulators, such as SCARA robots, have been designed with mechanical frames connected by joint actuators, and their functionality has mainly been imposed by the intelligence of control algorithms. The musculoskeletal structure of animals including humans, however, is different from these mechanical frames of robots. In this research, the kinematics, statics and dynamics of a two-link manipulator are analyzed with a biarticular actuation mechanism, which is inspired from the musculoskeletal structure of animals and is utilized in the controller design. It is proved that the biarticular actuation mechanism makes the control of the end-effector easier, more robust, and more intuitive than typical actuation mechanisms. For the most effective and convenient expression of the equation of motion, the rotating coordinate system is adopted while most of the robotic manipulators are analyzed in the fixed coordinate system. Based on the derived equation of motion of a robotic manipulator in the rotating coordinate system, a disturbance-observer-based controller is proposed for realization of the Spring Loaded Inverted Pendulum (SLIP) model, which is a common model of human lower extremities but has seldom been realized in practice.

 Experimental setup with a biarticular actuation system