Research On Safety Tracking Control Of The Endoscopic Surgery Assisted Robot Based On Constraints

Endoscopic sinus surgery as the most effective way to solve nasal inflammation has been used by various hospitals and surgeons.Traditional operation needs doctor hold the mirror by one hand while hold surgical instrument by another hand.Because of the nerves and blood vessels around the nasal cavity,trembling of th e doctor's hand not only causes instability in the picture,but also brings potential danger.At the same time,communication problems between the doctor and his assistant can also cause delays and dangers in the operation.Scholars have proposed a variety of solutions to replace the doctor to hold the mirror,so as to improve the efficiency and safety of surgery in the two-handed mode.Based on the robot system proposed by previous scholars,this paper presents an operation solution of robot automatic servo following motion based on virtual fixture space constraints,which enables the robot to receive virtual constraints in space so as to effectively protect the human nasal cavity and achieve good human-computer interaction characteristics.Under the protection mechanism,the robot can follow the doctor's hand in real time and dynamically,which greatly improves the operation efficiency.Nowadays,the development of the nasal robots lack of safety constraints with simple control modes: most of the robots use force sensor threshold as safety protection mechanism,which has poor effect and low safety,and most of them use pneumatic or hydraulic joint locking mode.Doctors need to interrupt operation frequently.To adjust the position and posture of the robot,or adopt a simple linear joint control mode.Based on this,an innovative robot servo control scheme based on virtual fixture constraints is proposed in this paper.In order to obtain the real-time state of the current robot in the operating field,the dist ortion of the endoscopic image is corrected firstly,and the state of the current device end is obtained by image processing technology,which provides the basis for robot perception.At the same time,in order to realize the constraints of the robot in th e virtual space,a series of space key points near the nostril can be used to fit the base circle plane of the nostril.Combined with hyperboloid parameters,a flexible hyperboloid virtual fixture can be constructed,and a robot constraint algorithm is constructed based on the threshold contact force model of the nasal tissue.We use the ICP registration algorithm to realize the spatial registration of the three-dimensional infrared positioning device NDI and the robot,and put forward the following control strategy and human-computer interaction based on the pedal.The robot integrated system based on hierarchical control is developed and implemented by C++ language and QT software.The validation experiments of flexible virtual fixture and automatic follow-up control verify the validity and accuracy of follow-up control under the virtual constraints of robot,thus we can say this method can improve the efficiency and safety of operation.The innovative method proposed in this experiment has been proved to m eet the clinical requirements,but the development of nasal surgery robot still needs to solve some difficult problems,and has a long way to go.