Kinematics analysis and trajectory planning for a breast intervention robot under MRI environment

Breast cancer is one of the most common cancers and the principal cause of cancer death among women in the worldwide. Breast biopsy is a way to obtain tissue samples to determine if people suffer from breast cancer. Magnetic Resonance Imaging (MRI) can present the better performance in breast imaging than ultrasound or computed tomography, therefore a breast intervention robot for MRI guided biopsy of the breast was proposed in this paper. The structure of robot is nonmagnetic and thus the robot can operate safely within MRI scanner. Based on the study of the structure of the robot, the forward kinematics and inverse kinematics model of the robot was set up. According to the kinematics analysis and modeling, quintic polynomial interpolation methods were used in the trajectory planning of robot motion. Then the kinematics was also calculated by simulations. The simulation results showed that it can guarantee the continuous displacement, velocity and acceleration of joints. The smooth movement of the robot is vital to the physician, patient and robot itself, which helps to improve the safety of patient and the security of robot. Finally, the robot model was established and an experiment was carried out to prove that the robot runs smoothly and position accurately.