How about using pneumatic knee joint for Low Limb Prosthesis?
According to movement and stability, there are single axis,pneumatic 4-link knee joint, pneumatic 5-link knee joint, etc. according to the cylinder, there are single cylinder and double cylinder. General prosthetics are modular, a set of products including the receiving cavity, knee joint, connector, connecting rod, foot plate, outer packaging, etc. For the patients with Low Limb Prosthesis, it has always been a difficult problem to choose the pneumatic joint or the hydraulic joint.
Whether hydraulic or pneumatic knee joint is a passive prosthesis, walking is realized by the leg swing driven by the thigh stump. According to the changes of external conditions, the knee joint damping moment of the thigh prosthesis can be adjusted to achieve gait adjustment. Because the control mode is relatively simple, the difficulty of implementation is relatively small, and the energy consumption is relatively low, it has been widely used. The intelligent thigh prosthesis belongs to the active prosthesis, which mainly uses the motor as the power source, which can provide the moment instead of the leg muscle, and make the knee joint bend and stretch actively.
According to the structure, knee prosthesis can be divided into single axis prosthesis and multi link prosthesis. The single axis knee joint has only a single rotation axis, so it has high flexibility in the swing period, but it is not stable in the support period. Most of the multi axis knee joints are multi link knee joints (four, five or six). The design of multi link mechanism enables the rotation center to move in a certain trajectory, which is more in line with the change of the knee joint rotation center during normal walking of human body. The rotation instantaneous center can be larger than the rotation axis during stretching, and it can quickly descend to the vicinity of the rotation axis during bending, so that it can stretch flexibly and support at the same time It's also stable. The single axis pneumatic knee joint is suitable for the patients with long stumps. It is characterized by the flexibility of the joint body, and the disadvantage is that it is not easy to control. The air pressure knee joint with four-bar linkage has many suitable types of residual limbs, and its characteristics are relatively stable.
Pneumatic knee joint: high flexibility, small motion damping, low requirement for force, gentle and gentle swing, low requirement for temperature (basically not affected by temperature), light weight of gas. Disadvantages: because the air compression rate is slightly larger (in place) and the accuracy is slightly worse than the hydraulic pressure (but people's weight is generally within 150 kg, so the compression rate is very small, so the impact is not significant).
At present, the multi axis pneumatic knee joint is more loved by the prosthetic patients. Compared with the single axis pneumatic joint, the multi axis joint is better in safety, more stable in practical performance, and more beautiful in walking gait. For example, AOSUO's AS2906 five-link joint has a unique cylinder design that acts as a powerful booster during walking, making it easier and more natural for the patient to walk. It can make the joints produce 0-10 knees when walking, achieve effective natural cushioning, aeroelastic safety function, prevent knees, maintain normal and stable gait, and absorb the reaction force generated by the prosthesis landing, let the wearer walk Natural and gait is easy.
AOSUO'sAS30 Knee joint is a polycentric knee joint with pneumatic swing control that is best suited to be used by moderate to K3 level activity and with higher degree of safety. The frame construction is made of aluminum alloy and the 4-bar linkage is made of aircraft alloy(AA7075). All axes have built-in bearing which allow ultra smooth walking movement. The proximal attachment has A-P slide and rotating adjustment. Optional adapters are pyramid adapter(for AK) and lotus adapter(for KD). This product has a 1 year warranty.