The kip is a fundamental gymnastic movement performed on a variety of gymnastic apparatus at all levels of competition. We analyze the kip with a reduced model approach consisting of a pendulum and 3-link system. Our simulations have shown that a variable length pendulum is sufficient for modeling the dynamics of an expert gymnast's center-of-mass without considering the complex parameters of the 3-link system. The optimized pendulum model can generate kip pattern variations which are evaluated based on the center-of-mass and 3-link system's total energy. A comparison of the performances of robot, simulator and human expert identifies (1) body arching during the forward swing, (2) a quick piking movement, and (3) grip adjustment during the backward swing as characteristics common to success. These results suggest a guideline for performing the kip successfully.

The authors present a system for coaching novice gymnasts in performing the kip based on detailed body information. They study the kip using a pendulum and kinematically redundant 3-link model. Their simulations have shown that a variable length pendulum model is sufficient for modeling the dynamics of an expert gymnast's center-of-mass without considering the complex parameters of the 3-link model. The authors optimize the dynamics equations of the pendulum using boundary conditions obtained from an expert gymnast's center-of-mass trajectory. By varying these conditions they discover target and timing regions of success and other finds of basic coaching information. The authors input this information to the 3-link model to obtain detailed coaching information such as center-of-mass trajectories matched to the user's body characteristics and corresponding torque data. This system improves on current coaching techniques for the kip.

Most work on compliance or force control schemes in doing precision assembly has been insufficient to provide satisfactory performance, and therefore applications to manufacturing have been few. The remote centre compliance (RCC) device is the most famous of the passively compliant devices and has been already used in some operations. However, it is well known that the RCC has some limitations in flexible precision assembly automation: its characteristics (such as the position of remote compliance center and compliance at the point) are not variable. The device has not in fact been improved since its invention 20 years ago. To confer more flexibility to a robotic assembly line, we developed a cost-effective, compact, and lightweight variable RCC (VRCC). The invention of a simple but unique mechanism enabled the fabrication of the variable RCC. The device eliminates the need for an additional complex electrical control system or theory to cope with variation. Moreover, we have verified that a single VRCC duplicates the performance of a wide range of commercially available fixed-type RCCs.

The mechanical behaviour of RCC devices using elastomer shear pads is influenced by the number of rubber-metal layers, thickness and radius of the rubber and metal, and axial and lateral stiffness of the rubber (elastomer). These parameters have to be considered for a complete analysis or design of the RCCs. We present a useful method of analyzing the behaviour of RCC based on the basic knowledge of the mechanics of materials. This makes it easy to design a new RCC for a specific purpose. Simulation and experimental results are also presented.