Research On Steering Resisting Torque And Turning Radius Of Crawler Crane

Steering resisting torque and turning radius are key technical parameters of crawler cranes. In traditional arithmetic, the force which generates steering resisting torque is simplified as forces with equal value or with linear relationship, resulting in an inaccurate calculation result of steering resisting torque. The impact of track block sliding on track velocity is not taken into account according to traditional arithmetic of turning radius, resulting in an inaccurate calculation result of turning radius. Therefore, proposing an accurate calculating method of steering resisting torque of crawler cranes, figuring out the relationship between turning radius and driving speed, is of great significance for guiding type selection of traveling mechanism and improving the controlling and operating performance of crawler cranes.In the paper, a moving coordinate stationary relative to the chassis is set up based on the analysis of velocity of arbitrary point on the track block. By coordinate transformation, it derived a velocity equation of arbitrary point on the track block. The direction of friction caused between the ground and the contacting point on the track block is opposite to the direction of velocity, so as to determine the value and direction of the friction which causes the steering resisting torque. Derived the calculating equations of traction force, steering resisting torque and turning Radius under three different stable steering modes where the unknown variable are expressed with the steering angular velocity. These three steering styles are differential, unilateral brake and bilateral reverse brake. Steering kinematics equations are set up and solved to get the steering angular velocity. Steering angular velocity, turning Radius, steering resisting torque calculated by methods of this paper are compared with traditional arithmetic. A simulation of these three different steering modes is conducted based on virtual prototyping technology.The result of research indicates that the longitudinal component force of the fraction caused between ground and track block provides the steering driving force, while lateral component force acting as the steering resisting force. Steering driving force equals to steering resisting force during the process of stable steering. Steering resisting torque has nothing to do with the velocity of driving force, and the calculated steering angular velocities are 75% of the traditional calculation results. As to the differential mode, different driving speeds determine different steering angular velocities and turning Radius. The turning Radius is 1.3 times as large as traditional calculation results. As to the unilateral brake mode, turning Radius has nothing to do with velocity of driving force, the steering resisting torque is 90% of traditional calculation results; Turning Radius keeps at zero in the bilateral reverse brake mode, the steering resisting torque is 1.3 times as large as traditional calculation results. Calculating method proposed in this paper is more accurate than traditional ones.