Road Bump Detection Using LiDAR sensor for Semi-Active Control of Front Axle Suspension in an Agricultural Tractor

Abstract

The front axle suspension system of an agricultural tractor plays a major role in both increasing its traction force and reducing its front vibration. Since agricultural tractors are easily exposed to severe road conditions, it is necessary to effectively control the damping characteristics of the front suspension in response to the varying ground conditions. This paper describes the development of a method that detects road surface obstacles using a LiDAR sensor to predict a change in the ground condition in advance. The roughness of the road surface was quantified by comparing the difference of averaged distances value between each of locations measured with the LiDAR sensor in region of interests. Use of the LiDAR sensor mounted in front of the tractor enabled both the roughness condition of road surface and the presence of bump to be detected in a typical range of traveling speeds of tractors when using threshold values suitable for distinguishing between a bump and other objects. It was found that the developed road surface detection system could be employed in a preview semi-active control system that can vary the damping characteristics of the front axle suspension according to road conditions due to the ability to detect the road bump with an accuracy of 78.6% and at 5.0m before the bump was reached. Results of field tests showed the vertical acceleration of the vehicle body was reduced by 54%, when passing the bump at 5 km/h and axle displacement was reduced by 51% when travelling an even road at 5 km/h, as compared to those obtained with the tractor without the road bump detection system.