OBJECTIVE: To design an electronically controlled hydraulic damper cylinder as a key part of the computer-controlled intelligent knee joint.METHODS: According to the characteristics of hydraulic fluids and processing technology, new type of micro-structure of the digital throttle and unique structure of the two-cylinder piston had been applied to the damper. It could control extension and flexion of the knee joint in two-way automatically, which improved the gait symmetry of artificial limb. Finally, a special self-made testing device was used to evaluate the performance of the hydraulic damper. The damping force adjustment was simulated in test by controlling the two needle valves with micro-computer. The kinematics speed was detected under different state of simulating the driving moment of hip joint and the damping moment of knee joint. The testing results indirectly built the dynamics relationship among the inertial force, damping force and the swing speed of the knee joint. RESULTS: When the position value X of the needle valve was reduced by the step motor driving, the resistance of the hydraulic cylinder was increased which resulted in faster speed of the cylinder rod. The sensitivity of the speed to the driving force decreased with the opening of needle valve increasing. When the stepping motor controlled the needle valve closer, the damping moment increased which led to a faster swing speed.CONCLUSION: The design of hydraulic damper cylinder meets the requirements of prosthetic knee dynamics control.

Complicated characteristic of facial modality acquisition and measurement is commonly needed in clinical environment.Two different methods were compared, one method was acquisition two-dimensional character based on the principle of machine vision with a charge-coupled device (CCD) capturing image, and another method was acquisition three-dimensional character based on the technology of Reverse Engineering with laser scanning capturing image. The principle, composition of the system, calibration and characteristics of different method are analyzed. Two-dimensional and three-dimensional facial data of thirty undergraduates was used to compare different methods. The application and restriction of different methods are concluded. The conclusion of this paper provided a reference for face plastic surgery, facial paralysis, facial surgical evaluation and rehabilitation design.