Combining extremum seeking control and tracking control for high-performance CVT operation

Abstract—The control design for the variator in a pushbelt continuously variable transmission (CVT) is investigated. The variator enables a stepless variation of the transmission ratio within a finite range. A conventional variator control design is typically obtained by the use of a variator model, which is highly uncertain and, therefore, limits the variator efficiency. In this paper, a variator control design is proposed, which simultaneously satisfies the variator control objectives: 1) track-ing a transmission ratio reference, 2) optimizing the variator efficiency. Furthermore, the variator control design, which con-sists of a combination of extremum seeking control (ESC) and tracking control (TC), only uses measurements from sensors that are standard. Experiments illustrate that the variator control design achieves the variator control objectives and show that a conventional variator control design is outperformed. I

Improving pushbelt continuously variable transmission efficiency via extremum seeking control

Abstract onl

Improving pushbelt continuously variable transmission efficiency via extremum seeking control

The control design for the variator in a pushbelt continuously variable transmission (CVT) is investigated. The variator enables a stepless variation of the transmission ratio within a finite range. A conventional control design for the variator is typically obtained by the use of a variator model, which incorporates large uncertainties and, therefore, limits the variator efficiency. In this paper, a control design for the variator is discussed, which improves the variator efficiency and limits the number of sensors. The relation between inputs and outputs of the variator is investigated, from which one input-output map is identified, which exhibits a maximum. This maximum indicates performance in terms of the variator efficiency. For this reason, this input-output map is maximized by means of extremum seeking control (ESC), which omits the use of a variator model. Experiments illustrate that the approach is feasible and show that a conventional control design for the variator is outperformed