Tool exchange is inevitable in laparoscopic surgery. Manual tool exchange is time consuming and may cause trauma. To overcome this issue, we have developed an electro-hydraulic manipulator that is capable of carrying 4 different surgical instruments. This manipulator is small enough (OD:14 mm, length: 55 mm) to be inserted inside body from natural orifices such as mouth.

Previous designs used miniature electric motors to change and actuate instruments. With electric motors there is always a trade-off between size and robotic capabilities (speed, torque, force). As a result, previous designs are bulky, slow, expensive, not disposable, with the risk of producing heat and leaking electricity. In our design we used a master-slave system. The master system with all electronics would be place ex-vivo, whereas the manipulator with no electronics would work in-vivo. This electro-hydraulic multi-instrument manipulator is much faster and smaller than the previous electric versions.