| Master-slave vascular interventional surgical robot has become a research hotspot in the field of robotics in recent years.In this paper,the robot is improved from the perspectives of transparency,safety and instantaneity.Firstly,the place tracking between the master side and the slave side of vascular interventional surgical robot can only be realized,but the speed tracking cannot be realized.In order to solve this problem,a new control system was designed in this paper.The idea of integral equivalence was used to divide the movement into several segments,and then the speed tracking was achieved by tracking the speed of small segments.The transparency of the vascular interventional surgical robot was guaranteed by the new control system.Secondly,long-time and stressful vascular interventional surgery are likely to cause tremors,this paper proposes a tremor elimination strategy,which classifies the tremor and filters out the tremor according to the law of physiological tremor.According to the known safe contact force between the guide wire/ the catheter and the vessel wall,the impulse theorem is used to obtain the safe rate of speed change,and the stress tremor is identified by comparing the movement speed of the hands with the safe rate of change,and the self-locking function is added to ensure the safety of the system.Then,since the vascular interventional sugical robot is the master-slave system and the control logic itself is hysteresis,the sampling interval of the master manipulator in the process of collecting doctors’ actions will become the time delay of the vascular interventional surgical robot system.Faced with this problem,a time delay error predictive control method is proposed in this paper.The predictive model is used to carry out feed-forward control for vascular interventional surgical robot system,and a double-closed-loop control structure is proposed to overcome the instability problem of feed-forward control method.The time delay error predictive control method ensures the instantaneity of vascular interventional surgical robot.Finally,experiments are carried out to verify the effectiveness of the tremor elimination strategy and time-delay error predictive control method.First,the verification experiment of tremor elimination strategy was carried out,and the average success rate was 92.85%.Secondly,to test the effect of time delay error predictive control method,two groups of master-slave tracking experiment was carried out,first experiment simulated the process of continuously pushing the guide wire and catheter manipulator into the vertical blood vessel,and monitored by the NDI optical tracking system.The experimental results were as follows: the average error of catheter manipulator is 0.41 mm,the average error of guide wire manipulator is 0.386 mm.The second experiment was to simulate the process of the catheter and guide wire entering the complex vascular environment: push the catheter and guide wire to move a distance and stop,twist the operation to adjust the direction and then continue moving.The NDI optical tracking system was used for monitoring.The experimental results were as follows: the average error of the catheter manipulator was 0.402 mm,and the average error of the guide wire manipulator was 0.36 mm.To sum up,the tremor elimination strategy and time delay error predictive control method proposed in this paper ensure the security,instantaneity and transparency. |
