Automated Bucket Stabiliser for Hydraulic Mobile Machine

A small general-purpose teleoperated hydraulic mobile machine is studied at the Institute of Hydraulics and Automation at the Tampere University of Technology. The boom and the bucket of the machine are normally controlled with a joystick. Horizontal movement of the joystick controls the bucket and vertical movement controls the boom. An angle of the bucket, compared to the horizontal level changes while the boom is moved up and down, unless the change of a boom angle is compensated by controlling the bucket manually at the same time. However, compensation is difficult during the driving. This paper describes a bucket stabilizer system which compensates the change of the boom angle automatically and makes so controlling of the machine easier for an operator.

A mechanical structure of the machine causes some limitations for the bucket stabilizer system. For instance, the angle of the bucket can not be maintained while the boom is moved if the bucket is already in the extreme position. These special situations are considered and error conditions are prevented.

The angle of the boom and the bucket compared to the horizontal level are measured with help of accelerometer sensors. The calculation operations are distributed. On this account, the system is independent from existing control electronics of the machine. Communication between the control electronics of the machine and the bucket stabilizer system is carried out with CAN bus. The structure of the electronics of the system is introduced in this paper. Also the design and implementation of the control algorithm are introduced. The measured results of the automated bucket stabilizer system are shown. Simulated results are compared to measured values. User experiences are also enclosed.