Active fixturing: literature review and future research directions

Fixtures are used to fixate, position and support workpieces and represent a crucial tool in manufacturing. Their performance determines the result of the whole manufacturing process of a product. There is a vast amount of research done on automatic fixture layout synthesis and optimisation and fixture design verification. Most of this work considers fixture mechanics to be static and the fixture elements to be passive. However, a new generation of fixtures has emerged that has actuated fixture elements for active control of the part–fixture system during manufacturing operations to increase the end product quality. This paper analyses the latest studies in the field of active fixture design and its relationship with flexible and reconfigurable fixturing systems. First, a brief introduction is given on the importance of research of fixturing systems. Secondly, the basics of workholding and fixture design are visited, after which the state-of-the-art in active fixturing and related concepts is presented. Fourthly, part–fixture dynamics and design strategies which take these into account are discussed. Fifthly, the control strategies used in active fixturing systems are examined. Finally, some final conclusions and prospective future research directions are presented

Active decoupler hydraulic engine mount design with application to variable displacement engine

In automotive industry, engine vibration isolation has been a challenging task, and given the emergence of new vehicles with more stringent performance characteristics, engine vibration isolation has become an even more demanding issue. Most engine mounts are passive — that is, their parameter values and characteristics are fixed — and as a result, they may not properly attenuate the complicated vibration transmitted from the engine. In this paper, the development of a new active mount is described. This paper describes modeling, development, and experimental analysis of an active engine mount, which is specifically designed to address the Variable Displacement Engine (VDE) isolation problem. An electromechanical actuator is fabricated and retrofitted inside the inertia track plate of a hydraulic engine mount. The plunger of the electromechanical actuator moves upon receiving the signal from the controller, and it changes the dynamic performance of the mount accordingly based on frequency, amplitude, and phase of the activation signal. Experimental results are presented for different control signals. Simulated and experimental results are compared to validate the mathematical model. The experimental results demonstrate the performance of the designed active engine mount to deal with complicated vibration patterns, specifically those created by VDEs. </jats:p