Experimental Study of PD Controller for Engagement Control of an Electro-Mechanical Friction Clutch (EMFC) System M. S. CHE KOB, M. HUSSEIN, B. SUPRIYO, K. B. TAWI, M. Z. MD ZAIN AND S. ARIYONO * Faculty of Mechanical Engineering, Universiti Technologi Malaysia 81310 UTM Skudai, Johor, MALAYSIA *Faculty of Mechanical Engineering, Universiti Malaysia Pahang 26600, Pekan, Pahang, MALAYSIA e-mail: salman_qlte@yahoo.com.my Abstract: - Nowadays, most of the clutches used in continuously variable transmission (CVT) applications are based on electro-hydraulic and electro-magnetic actuations. The designs of these clutches cause some energy losses due to the actuated clutches need continuous power to supply force to engage the clutches. This continuous energy consumption becomes one of the major losses in CVT’s clutches system as it can reduce the transmission efficiency. Therefore, this paper attempts to introduce a novel electro-mechanical friction clutch (EMFC) system as a viable solution for reducing the power loss in CVT applications. This EMFC consists of mechanical actuator, a standard dry friction clutch, clutch linkages and a DC motor. The DC motor is used to power the mechanical actuator via power screw mechanism. This paper proposes proportional differential (PD) controller to control the DC motor such that the mechanical actuator satisfy the desired engagement and disengagement processes of EMFC system. The initial values of the PD gains are derived using Astrom and Hagglund tuning method and Ziegler-Nichols formula. Then, these gains are manually fine tuned to improve the performance of the clutch engagement control until satisfying the predetermined optimal global criterion. Experimental results are presented to demonstrate the effectiveness of the proposed controller and discussed with considering different operating conditions and the dynamic behaviours of the clutch. Key-Words: - Electromechanical Friction Clutch, Clutch Engagement Control, PD Controller. 1 Introduction With the current trend for the theorised threat of global warming and pollution control, it is important for car manufactures to minimise fuel consumption and exhaust emissions. Parallel with the demand for driving comfort which has become a priority at all levels in the market and increasingly competition from other manufactures a way to reduce costs is highly needed. Thus, the trend towards more highly automated transmissions will play important role in future automotive systems. Different approaches, such as automatic transmission (AT), automated manual transmission (AMT) and continuously variable transmission (CVT) are exploiting the availability of reliable drive-by-wire technologies. These transmissions represent the key elements for the improvement of vehicle safety, comfort, reliability and driving performances as well as the reduction of fuel consumption and emissions [1]. For example, vehicle with AMT is generally constituted by a dry friction clutch-by-wire system as means of easing the driver’s task and thus, enhancing driving satisfaction [2]. Clutch- by-wire gives the possibility to handle high torques form the engine without needing too high pedal force at the clutch pedal. With respect to manual transmission, the AMT allows to improve driving comfort and shift quality by controlling the dry clutch engagement process. The engagement of dry friction clutch is a very important process both to ensure small friction wear and good power-train performance [3-5]. Currently, most of the clutches used in CVT applications are based on hydraulic and electro-magnetic actuations. These clutches are selected because they can be controlled electronically [5]. Relating to this technology, a novel electro-mechanical friction clutch (EMFC) system for a novel electro-mechanical dual acting pulley (EMDAP) CVT applications have been developed by Vehicle Powertrain Research Group (VPRG) in Universiti Teknologi Malaysia (UTM) as the future generation transmission. The EMFC consists of mechanical actuator, a typical dry friction clutch, clutch linkages and a DC motor. The DC motor system is used as an actuator to actuate power screw mechanism for Recent Researches in Computational Techniques, Non-Linear Systems and Control ISBN: 978-1-61804-011-4 27