Design And Implementation Of Six Degree Of Freedom Chewing Machine

The human chewing system is mainly driven by mandibular movement of masticatory muscles,upper and lower jaw,teeth,temporomandibular joint and other components.The mandibular as a rigid body in the space with 6 degrees of freedom in the completion of the chewing movement process in the smaller work space need to output a larger chewing force.Chewing machine is based on the characteristics of human jaw masticatory movement,simulation of human mandibular chewing process,and applied to food chewing characteristics of experimental and denture material characteristics of the experimental equipment.In this paper,the characteristics of mandibular structure and its chewing movement are analyzed.Based on the degree of freedom and advantages and disadvantages of 6RSS parallel mechanism,the mechanical structure of chewing machine based on 6RSS parallel mechanism is selected and designed.The chewing machine uses six bus actuators mounted in the same fixed plane as actuators to drive the mandibular movement platform through a given chewing trajectory through six RSS sports chains.Through the analysis of the mandibular motor trajectory and the biomechanical characteristics,the mandibular movement pattern is simplified,and the human mandibular chewing movement is divided into three types.According to the different types of mandibular chewing movement,the corresponding parameter equation is established,which is the chewing machine The design of the trajectory of the mandibular canal is provided.At the same time,the position inverse solution,velocity Jacobian matrix and static Jacobi matrix are solved for the 6RSS parallel mechanism,which provides the theoretical basis for the motion control of the chewing machine.Modeling of the mandibular movement platform in SolidWorks,and imported into ADAMS to establish the virtual prototype design,the complete trajectory of masticatory mandibular,inverse kinematics simulation by transformation curve input angle,angular velocity and angular acceleration in ADAMS,to verify the correctness of the inverse position.Taking the result of inverse solution as input,the virtual prototype is simulated with positive dynamics.The change of input torque is obtained,and the angle curve of spherical hinge is analyzed to see whether the maximum rotation angle is exceeded.The given masticatory trajectory satisfies the geometric constraint condition of the mandibular motion platform.The type selection and controller selection of the chewing machine are carried out.The bus servo system is selected as the driver and the STM32F4 chip is used as the controller.The hardware circuit of the smallest core system of the master chip is designed and made.Use Labview write PC chewing machine,adopting off-line inverse method by the host computer to send the steering angle,and the preparation of actuator motion hypogynous machine control program,pressure acquisition program,attitude acquisition program,OLED driver.The master chip collects the attitude of the MPU6050 through the IIC bus,and the collected attitude and acceleration information can be printed to the third party host computer for real-time display and storage.The film pressure sensor is used to collect the pressure changes at the teeth,and then the pressure signals are displayed on the OLED through the SPI bus.