Simulation of Upward Jump Control for One-Legged Robot Based on QP Optimization.

An optimization framework for upward jumping motion based on quadratic programming (QP) is proposed in this paper, which can simultaneously consider constraints such as the zero moment point (ZMP), limitation of angular accelerations, and anti-slippage. Our approach comprises two parts: the trajectory generation and real-time control. In the trajectory generation for the launch phase, we discretize the continuous trajectories and assume that the accelerations between the two sampling intervals are constant and transcribe the problem into a nonlinear optimization problem. In the real-time control of the stance phase, the over-constrained control objectives such as the tracking of the center of moment (CoM), angle, and angular momentum, and constraints such as the anti-slippage, ZMP, and limitation of joint acceleration are unified within a framework based on QP optimization. Input angles of the actuated joints are thus obtained through a simple iteration. The simulation result reveals that a successful upward jump to a height of 16.4 cm was achieved, which confirms that the controller fully satisfies all constraints and achieves the control objectives.

Structural improvement and analysis of a novel endoscopic succession closing device / 医用生物力学

By developing a novel endoscopic succession closing device to overcome the shortcomings of existing devices that cannot deploy several clips at a time, to perform structural analysis on different clamp structures and to validate their performances in tissue closure through finite element analysis. Methods Comparative analyses of three clamp structures, namely, the aligning tooth structure (original, clamp A), the staggered tooth structure (clamp B), a combination structure with page break angle and staggered tooth (clamp C), were performed to analyze pressure and its distribution on tissues when clamping the stomach wall. Displacement of 7.5 mm was then applied on the clamps to simulate the effect of the operating procedures of the device and tissue kick-back. Results The maximum stresses of the clamp A and B were located on the first pair of teeth which was closest to the rotating shaft, with the stress being 10.39 kPa and 10.11 kPa, respectively. The maximum stress (11.35 kPa) of the clamp C was located on the second pair of teeth. For clamp A and B, the longer the distance to shaft, the larger pressure on stomach tissues. While for clamp C, the pressure on device-tissue interface showed little change along the path. Under tensile displacement, clamp A and B slipped off from the tissue when displacements reached to 5 mm and 6.5 mm, respectively, while clamp C did not. Conclusions　Clamp with page break angle and staggered tooth can exert the uniform max pressure to tissues and provide a larger contact area away from the rotating shaft, thus improving anti-slippage and performance of the novel endoscopic closing device.

Structural improvement and analysis of a novel endoscopic succession closing device / 医用生物力学

Objective By developing a novel endoscopic succession closing device to overcome the shortcomings of existing devices that cannot deploy several clips at one time,to perform structural analysis on different clamp structures and to validate their performances in tissue closure through finite element analysis.Metbods Comparative analyses of 3 clamp structures,namely,the aligning tooth structure (original,clamp A),the staggered tooth structure (clamp B),a combination structure with page break angle and staggered tooth (clamp C),were performed to analyze pressure and its distribution on tissues when clamping the stomach wall.Displacement of 7.5 mm was then applied on the clamps to simulate the effect from operating procedures of the device and tissue kick-back.Results The maximum stresses of the clamp A and B were located on the first pair of teeth which was closest to the rotating shaft,with the stress of 10.39 kPa and 10.11 kPa,respectively.The maximum stress (11.35 kPa) of the clamp C was located on the second pair of teeth.For clamp A and B,the longer the distance to shaft,the larger pressure on stomach tissues.While for clamp C,the pressure on device-tissue interface showed little change along the path.Under tensile displacement,clamp A and B slipped off from the tissue when displacements reached to 5.0 mm and 6.5 mm,respectively,while clamp C did not slip off.Conclusions Clamp with page break angle and staggered tooth can exert the uniform maximum pressure to tissues and provide a larger contact area away from the rotating shaft,thus improving the anti-slippage and performance of the novel endoscopic closing device.

Structural improvement and analysis of a novel endoscopic succession closing device / 医用生物力学

Objective By developing a novel endoscopic succession closing device to overcome the shortcomings of existing devices that cannot deploy several clips at one time,to perform structural analysis on different clamp structures and to validate their performances in tissue closure through finite element analysis.Metbods Comparative analyses of 3 clamp structures,namely,the aligning tooth structure (original,clamp A),the staggered tooth structure (clamp B),a combination structure with page break angle and staggered tooth (clamp C),were performed to analyze pressure and its distribution on tissues when clamping the stomach wall.Displacement of 7.5 mm was then applied on the clamps to simulate the effect from operating procedures of the device and tissue kick-back.Results The maximum stresses of the clamp A and B were located on the first pair of teeth which was closest to the rotating shaft,with the stress of 10.39 kPa and 10.11 kPa,respectively.The maximum stress (11.35 kPa) of the clamp C was located on the second pair of teeth.For clamp A and B,the longer the distance to shaft,the larger pressure on stomach tissues.While for clamp C,the pressure on device-tissue interface showed little change along the path.Under tensile displacement,clamp A and B slipped off from the tissue when displacements reached to 5.0 mm and 6.5 mm,respectively,while clamp C did not slip off.Conclusions Clamp with page break angle and staggered tooth can exert the uniform maximum pressure to tissues and provide a larger contact area away from the rotating shaft,thus improving the anti-slippage and performance of the novel endoscopic closing device.

Structural improvement and analysis of a novel endoscopic succession closing device / 医用生物力学

Objective By developing a novel endoscopic succession closing device to overcome the shortcomings of existing devices that cannot deploy several clips at one time,to perform structural analysis on different clamp structures and to validate their performances in tissue closure through finite element analysis.Metbods Comparative analyses of 3 clamp structures,namely,the aligning tooth structure (original,clamp A),the staggered tooth structure (clamp B),a combination structure with page break angle and staggered tooth (clamp C),were performed to analyze pressure and its distribution on tissues when clamping the stomach wall.Displacement of 7.5 mm was then applied on the clamps to simulate the effect from operating procedures of the device and tissue kick-back.Results The maximum stresses of the clamp A and B were located on the first pair of teeth which was closest to the rotating shaft,with the stress of 10.39 kPa and 10.11 kPa,respectively.The maximum stress (11.35 kPa) of the clamp C was located on the second pair of teeth.For clamp A and B,the longer the distance to shaft,the larger pressure on stomach tissues.While for clamp C,the pressure on device-tissue interface showed little change along the path.Under tensile displacement,clamp A and B slipped off from the tissue when displacements reached to 5.0 mm and 6.5 mm,respectively,while clamp C did not slip off.Conclusions Clamp with page break angle and staggered tooth can exert the uniform maximum pressure to tissues and provide a larger contact area away from the rotating shaft,thus improving the anti-slippage and performance of the novel endoscopic closing device.