英语翻译A computer controlled robotic device (Phantom Premium 1.

英语翻译
A computer controlled robotic device (Phantom Premium 1.0,Sensable Technologies,Woburn,MA,USA) was used to deliver a load to the lower jaw.The robotic device was connected to a custom made acrylic-metal dental appliance via a magnesium-titanium rotary connector that offered fully unconstrained movement of the jaw in the absence of external load.The dental appliance was attached to the buccal surface of the mandibular teeth with a dental adhesive (Iso-Dent,Ellman International,Hewlett,NY,USA).A force/torque sensor (ATI Nano-17,ATI Industrial Automation,Apex,NC,USA) was mounted at the tip of the robotic device to measure the resistive force applied by the subjects in opposition to the load.The subject’s head was restrained during the experiment by connecting a second dental appliance that was glued to the maxillary teeth to an external frame that consisted of a set of articulated metal arms.The metal arms were locked in place throughout the experimental session.
Jaw movement was recorded in three dimensions at a rate of 1 KHz and the data were digitally low-pass filtered offline at 8 Hz.The subject’s voice was recorded using a unidirectional microphone (Sennheiser,Germany).The acoustical signal was low-pass analogue filtered at 22 KHz and digitally sampled at 44 KHz.The robot applied a mechanical load to the jaw that resulted in jaw protrusion.The load varied with the absolute vertical velocity of the jaw and was governed by the following equation:F=k|v| ,where F is the load in Newtons,k is a scaling coefficient and v is jaw velocity in mm/s.The scaling coefficient was chosen to have a value of between 0.6–0.8,with a higher coefficient used for subjects who spoke more slowly and vice versa.The maximum load was however capped at 7.0 N.Jaw velocity estimates for purposes of load application were obtained in real-time by numerically differentiating jaw position values obtained from the robot encoders.The computed velocity signal was low-pass filtered using a first order Butterworth filter with a cut-off frequency 2 Hz.The smoothed velocity profile was used online to generate the protrusion load.