The applications of robotic fish require high propulsive efficiency mechanism to prolong the mission time. Though many methods were applied, robotic fish still suffers from low efficiency. To improve the efficiency of...The applications of robotic fish require high propulsive efficiency mechanism to prolong the mission time. Though many methods were applied, robotic fish still suffers from low efficiency. To improve the efficiency of robotic fish, this paper proposes a variable stiffness mechanism which is based on the negative work. The live fish adjusts its body stiffness to save energy when the muscles do negative work. Inspired by the live fish, a control mechanism based on negative work is proposed to change the stiffness of the robotic fish for higher efficiency. Changing the stiffness of the robotic fish is to change the joint-stiffness. A fuzzy controller is introduced to mimic the variable stiffness mechanism of the fish and depicts the relationship between the stiffness and the negative work. To evaluate the performance of this controller, a two-joint robotic fish model is established based on its kinematic model and hydrodynamic model. The evaluation results show that the robotic fish reduces the energy consumption and improves the propulsion efficiency when introducing the variable stiffness mechanism. Different environments with the control mechanism impact differently on propulsive efficiency. This mechanism may provide a high efficient propulsion control method for the robotic fish.展开更多
Photosensitive polyimide precursor containing glycol monocinnamate group was synthesized by a new method. The photoresist, made from the above polyimide precursor, was spin coated onto silicon wafers, prebaked...Photosensitive polyimide precursor containing glycol monocinnamate group was synthesized by a new method. The photoresist, made from the above polyimide precursor, was spin coated onto silicon wafers, prebaked and then exposed to UV light. The appropriate conditions of the photolithographic procedures were determined. This photosensitive polyimide precursor showed good light sensitivity and the polyimide which was obtained by heating the polyimide precursor had a high thermal stability.展开更多
基金Acknowledgment This work is supported by National Natural Science Foundation of China （under Grant Nos.： 61203353 and 61573038）.
文摘The applications of robotic fish require high propulsive efficiency mechanism to prolong the mission time. Though many methods were applied, robotic fish still suffers from low efficiency. To improve the efficiency of robotic fish, this paper proposes a variable stiffness mechanism which is based on the negative work. The live fish adjusts its body stiffness to save energy when the muscles do negative work. Inspired by the live fish, a control mechanism based on negative work is proposed to change the stiffness of the robotic fish for higher efficiency. Changing the stiffness of the robotic fish is to change the joint-stiffness. A fuzzy controller is introduced to mimic the variable stiffness mechanism of the fish and depicts the relationship between the stiffness and the negative work. To evaluate the performance of this controller, a two-joint robotic fish model is established based on its kinematic model and hydrodynamic model. The evaluation results show that the robotic fish reduces the energy consumption and improves the propulsion efficiency when introducing the variable stiffness mechanism. Different environments with the control mechanism impact differently on propulsive efficiency. This mechanism may provide a high efficient propulsion control method for the robotic fish.
文摘Photosensitive polyimide precursor containing glycol monocinnamate group was synthesized by a new method. The photoresist, made from the above polyimide precursor, was spin coated onto silicon wafers, prebaked and then exposed to UV light. The appropriate conditions of the photolithographic procedures were determined. This photosensitive polyimide precursor showed good light sensitivity and the polyimide which was obtained by heating the polyimide precursor had a high thermal stability.
