Work machine

Abstract

Detection accuracy of a device for obtaining a position of a blade is improved. A motor grader includes an antenna for reception of a satellite position determination signal arranged in a roof portion of a cab, a first IMU mounted on the cab, a second IMU mounted on a draw bar, a rotation angle sensor that detects an angle of rotation of a swing circle with respect to the draw bar, an inclination angle sensor that detects an angle of inclination of a blade with respect to the swing circle, and a controller. The controller obtains the position of the blade in a global coordinate system based on the satellite position determination signal received by the antenna and results of detection by the first IMU, the second IMU, the rotation angle sensor, and the inclination angle sensor.

1 . A work machine comprising:
 a vehicular body frame including a front frame and a rear frame pivotably coupled to the front frame;   a cab which an operator enters, the cab being mounted on the vehicular body frame;   a draw bar coupled to the front frame, the draw bar being swingable with respect to the front frame;   a swing circle supported on the draw bar, the swing circle being rotatable relatively to the draw bar;   a blade supported on the swing circle, the blade being inclined with respect to the swing circle;   an antenna for reception of a satellite position determination signal arranged in a roof portion of the cab;   a first sensor mounted on the cab, the first sensor detecting an inclination of the cab;   a second sensor that detects an angle of inclination of the draw bar with respect to the cab;   a third sensor that detects an angle of rotation of the swing circle with respect to the draw bar;   a fourth sensor that detects an angle of inclination of the blade with respect to the swing circle; and   a controller that obtains a position of the blade in a global coordinate system based on the satellite position determination signal received by the antenna and results of detection by the first sensor, the second sensor, the third sensor, and the fourth sensor.   
     
     
         2 . The work machine according to  claim 1 , wherein
 the first sensor is arranged in a ceiling portion of the cab.   
     
     
         3 . The work machine according to  claim 1 , wherein
 the first sensor is arranged directly under the antenna.   
     
     
         4 . The work machine according to  claim 1 , wherein
 the first sensor is arranged in a front edge portion of the cab.   
     
     
         5 . The work machine according to  claim 4 , wherein
 the cab includes an operator's seat where an operator takes a seat, and   the first sensor is arranged in front of the operator's seat.   
     
     
         6 . The work machine according to  claim 4 , wherein
 the cab includes a steering wheel for an operator to perform an operation for steering the work machine and a steering console on which the steering wheel is supported, and   the first sensor is arranged directly above the steering console.   
     
     
         7 . The work machine according to  claim 1 , wherein
 the cab is mounted on the front frame.   
     
     
         8 . The work machine according to  claim 7 , wherein
 the first sensor is arranged in front of a center of pivot of the front frame with respect to the rear frame.