Abstract: When a longitudinal straight traveling mode position A, an oblique traveling mode position B, a transverse traveling mode position C, or spin turning mode position D is selected by a traveling mode changeover switch 21, a signal corresponding to the selection is input to a controller 27. The controller outputs signals to turning actuators 15a and 15b for orienting driving wheels 11a and 11b toward the selected position. With this signal, the turning actuators 15a and 15b cause turning of the driving wheels 11a and 11b. At the same time, turning angle detection sensors 16a and 16b input signal indicative of turning angle of the driving wheels. When the turning angle becomes coincident with a preliminarily set angle, a signal for terminating turning is output to the turning actuators 15a and 15b. By this control, turning action of the turning actuators 15a and 15b is terminated with setting the driving wheels 11a and 11b at the position of the selected orientation.

Abstract: When a longitudinal straight traveling mode position A, an oblique traveling mode position B, a transverse traveling mode position C, or spin turning mode position D is selected by a traveling mode changeover switch 21, a signal corresponding to the selection is input to a controller 27. The controller outputs signals to turning actuators 15a and 15b for orienting driving wheels 11a and 11b toward the selected position. With this signal, the turning actuators 15a and 15b causes turning of the driving wheels 11a and 11b. At the same time, turning angle detection sensors 16a and 16b input signals indicative of turning angle of the driving wheels. When the turning angle becomes coincident with a preliminarily set angle, a signal for terminating turning is output to the turning actuators 15a and 15b. By this control, turning action of the turning actuators 15a and 15b is terminated with setting the driving wheels 11a and 11b at the position of the selected orientation.