Slip controller design and implementation in a Continuously Variable Transmission

Continuously Variable Transmissions (CVT) can be used to operate a combustion engine in a more optimal working point. Unfortunately, due to the relatively low efficiency of modern production CVT’s the total efficiency of the driveline is not increased significantly. This low efficiency is mainly caused by losses in the hydraulic actuation system and the variator. Decreasing the clamping forces in the variator greatly improves the efficiency of the CVT. However, lower clamping forces increase the risk of excessive belt slip, which can damage the system. In this paper a method is presented to measure and control slip in a CVT in order to minimize the clamping forces while preventing destructive belt slip. To ensure robustness of the system against torque peaks, a controller is designed with optimal load disturbance response. A synthesis method for robust PI(D)-controller design is used to maximize the integral gain while making sure that the closed loop system remains stable. Experimental results prove the validity of the approach

Are national greenhouse gas emissions reports scientifically valid

While countries have recently been accused of misreporting greenhouse gas emissions for their benefit, internationally agreed procedures minimize such possibilities and allow for new scientific results to be taken into account in a stepwise manner

Slip controller design and implementation in a Continuously Variable Transmission

Continuously Variable Transmissions (CVT) can be used to operate a combustion engine in a more optimal working point. Unfortunately, due to the relatively low efficiency of modern production CVT’s the total efficiency of the driveline is not increased significantly. This low efficiency is mainly caused by losses in the hydraulic actuation system and the variator. Decreasing the clamping forces in the variator greatly improves the efficiency of the CVT. However, lower clamping forces increase the risk of excessive belt slip, which can damage the system. In this paper a method is presented to measure and control slip in a CVT in order to minimize the clamping forces while preventing destructive belt slip. To ensure robustness of the system against torque peaks, a controller is designed with optimal load disturbance response. A synthesis method for robust PI(D)-controller design is used to maximize the integral gain while making sure that the closed loop system remains stable. Experimental results prove the validity of the approach

Personalised home media centre using semantically enriched TV-anytime content

The paper presents a design and middleware implementation of a personalised home media centre. The proposed system aims to constitute the fundamentals to go beyond existing media centres and electronic programme guides, in the sense of offering a personalised experience for a single and multiple users in a connected home environment. User’s characteristics, preferences and context are used to personalise the user’s experience of viewing and interacting with multimedia content on different heterogeneous devices. The TV-Anytime specification is used as the underlying content and metadata format for handling content from IP, digital broadcast and Blu-ray disc sources. We show how semantics can enrich the TV-Anytime content classification in order to achieve intelligent personalised content search and recommendations

Performance optimisation of the push-belt CVT by variator slip control

Continuously variable transmissions (CVTs) are applied in an increasing number of vehicles. Large ratio coverage allows for reduced engine speeds, which adds to both highway driving comfort and reduced fuel consumption. It becomes increasingly important to further improve the performance in terms of efficiency, robustness and torque capacity of the CVT. This paper describes the possibilities of improving the CVT by minimising variator clamping forces. This is accomplished by using slip control technology. This technique allows for the best possible transmission efficiency, combined with improved robustness for slip damage. This paper first describes the relation between variator slip and functional transmission properties. The conditions for optimum performance regarding efficiency and robustness are identified. This leads to the development of a variator slip controller. The remaining sections describe experimental results on two test rigs and in a production vehicle. The paper concludes with an outlook into further developments