Daqing Zhang

Power system control strategy for hybrid excavator based on equivalent fuel consumption

In order to enhance fuel economy of hybrid excavator system, a control strategy based on equivalent fuel consumption is introduced. Efficiency of motor and ultra-capacitor is converted to fuel consumption of engine, which is used to establish the equivalent fuel consumption function of the whole system and further to optimize the power distribution. A compensation function is introduced to ensure the ultra-capacitor working in the safe state of charge (SOC) by the way of modifying the result of optimization. A simulation is performed and the results show that the control strategy based on equivalent fuel consumption can effectively optimize the power distribution and improve fuel economy while the SOC of ultra-capacitor is maintained at reasonable range.

Adaptive control of hydraulic excavator manipulator

The retrofitted electro-hydraulic system and hardware architecture of control system for hydraulic robotic excavator was introduced; the model of electro-hydraulic system was derived according to the principle of LUDV system. on the base of the above and results of experiments, the model was simplified, and the reference model for control was given; An adaptive controller (AC) and the adaptive control law were developed from the local parameter optimum. The test experiment on the trajectory tracking control of the excavator bucket tip was carried out, The result of tracking objective line for the AC and PID controller were present respectively. Form these results, the errors between the tested data and the target data for PID controller are more than 110mm when the level tracking velocity of the bucket speed was 107mm/s; for AC in this paper are less than 100mm at the speed of 135mm/s, the maximal nonlinearity is reduced to 3.8% from 4.8%. It shows that the proposed AC in this paper is valid and feasible.