冗余驱动仿下颌运动机器人工作空间分析及试验验证

Workspace Analysis and Experimental Verification of a Redundantly Actuated Jaw Movement Robot

根据人类下颌系统冗余驱动的生理特性,即下颌受颞下颌关节约束且受多于本身自由度数目的下颌肌肉驱动的特点,介绍了一种采用点接触高副模拟人体颞下颌关节的6PUS-2HKP(higher kinematic pair)冗余驱动并联机构来完成下颌运动,该机构可应用于牙科义齿性能测试.首先,建立机器人的坐标系,针对机构存在点接触高副的特点,分析和推导了冗余并联机构的独立位置参数和运动学方程.然后,采用下颌运动轨迹描记仪对实验对象下颌切点边缘性运动进行了采集.通过分析各驱动机构及点接触高副的运动范围,采用数值分析的方法获得了机器人的工作空间.最后,采用实验的方法,测量了仿下颌运动机器人做最大运动时下颌切点的运动轨迹.通过对比实验对象切点边缘性运动和工作空间仿真结果可知,该仿下颌运动机器人能够满足人类下颌运动空间要求.

The mandible is constrained by temporomandibular joint （TMJ） and actuated by more numbers of muscles than its own degrees of freedom （DOF）, so the human mastication system is redundantly actuated. Based on this characteristics, a redundantly actuated parallel mechanism with point contact higher kinematic pair （6PUS-2HKP） for simulating mastication movement is introduced, which can be used for dental materials testing. Firstly, the coordinate system of the robot is established. Considering the characteristics of existing point contact higher kinematic pairs, the position parameters and the kinematics equation of the redundant parallel mechanism are analyzed and derived. The border movement of the test subjects’ mandibular incisor point is obtained by using the mandibular kinesiograph in the experiment. The workspace of the redundantly actuated robot is analyzed with numerical method through calculating the movement ranges of the driving rods and the point contact higher kinematic pairs. The trajectory of the lower incisor point of the robot is measured through experiment when the robot moves along the edge of the largest workspace. Comparing with test subjects’ border movement and the simulated workspace result, it is shown that the jaw movement robot can meet the movement space requirements of the mandible.