In hydraulic drive systems for commercial vehicles, such as excavators and cranes, solenoid valves are used for power distribution. These are usually subject to manufacturing tolerances and thus to large parameter variations.
Adaptive control aims to achieve high control quality even with fluctuating, uncertain or unknown system parameters. In addition, adaptive control allows the same controller to be used in a class of structurally comparable systems. Due to the adaptive method, no manual adjustment of the controller parameters is required.
The researchers around Tobias Glück and Andreas Kugi (both Center for Vision, Automation & Control) present an adaptive and high-performance current control method for solenoid valves. It consists of an adaptive model-based feedforward and feedback controller, The system parameters are estimated using a tailored recursive least squares method.
The proposed solution differs from existing approaches in the adaptive feedforward control and the way parameter estimation is performed. The control concept is tested on three solenoid valves from different applications, which differ in their design and key parameters. The experimental results show high control performance and fast parameter convergence despite the nonlinear dependence of the inductance on current and position. The experimental results were also compared with two control schemes known from the literature. Both were outperformed by the proposed control scheme.
View the paper:
M. Schwegel, T. Glück, V. Shaferman, L. Zaccarian and A. Kugi, "Adaptive Two-Degrees-of-Freedom Current Control for Solenoids: Theoretical Investigation and Practical Application," in IEEE Transactions on Control Systems Technology, 2022, pp. 1-14.