Robotic horseback-riding simulators have been successfully used as a substitute for real horses in areas of therapy, riding lessons, fitness, and entertainment, and several have been developed. However, recent research has illuminated significant differences in motion, response, and feel between a real horse and a simulator, which may result in incorrect posture and muscle memory for the rider. In this study, we developed a hybrid kinematic structure horseback-riding simulator to provide more realistic motion than currently available ones. The basic system has 4 degrees of freedom and provides a base motion platform. An additional revolving system with 2 degrees of freedom is mounted on the base platform. Real horse motion data were captured, normalized, filtered, and fitted to provide the motion trajectory. Furthermore, active neck, saddle, and tail mechanisms were implemented to provide realistic simulation. For interactive horse riding, bridle and beat sensors were included to control the simulator motion and a large screen was installed for virtual reality effect. Expert tests were conducted to evaluate the developed horseback-riding system, the results of which indicated that the developed simulator was considered sufficient for riding lessons and therapeutic use.

This paper deals with the kinematics and analysis of a new parallel mechanism with a suspended platform. The proposed mechanism has a unique appearance in that the 6 chains originating from a circular ring are connected to the both ends of a suspended platform. After introducing the kinematics, the architecture singularity problem is analyzed. Then, the kinematic characteristics of this mechanism are analyzed with respect to the workspace and the isotropic index. Kinematic optimization of this mechanism was also performed. Finally, the proposed robot was employed as an automatic device for otologic surgery.

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The human body can be modeled as a kinematically redundant manipulator which exploits "redundant degrees of freedom" to execute various motions in a suitable fashion. Differently from the typical kinematically redundant robots that are attached to the fixed ground, the zero moment point (ZMP) condition should be taken into account not to fall down. Thus, this paper investigates a motion planning algorithm for kinematically redundant manipulator standing on the ground. For this, a geometric constraint equation is derived from the existing ZMP equation. This constraint equation is formed like a second-order kinematic equation, which enables one to plan the ZMP trajectory in a feedforward fashion. This constraint equation and the kinematic equation of the manipulator model are solved together. Then, the solution of this composite equation guarantees both the desired operational motion and the ZMP trajectory. The feasibility of the proposed algorithms is verified by simulating and experimenting several motions though a planar 3-DOF manipulator model.

The results show that the strategy allows for well controlled robotic end-effectors inside a predefined virtual wall by the robot itself and an operator through the signal and force feedback.