This paper compares the control performance of a distributed control system with variable sampling to actuation delay when using two different control solutions. The first one is a pole-placement controller with a fuzzy delay compensator and the second one an adaptive pole-placement with fractional dead-time modelling. The delay compensator is added to an existing controller that does not take ...

A key component of switch-mode hydraulic circuits is a highspeed two-position three-way valve with a variable duty cycle. This paper presents a new valve architecture that consists of two valve spools that are axially driven by crank-slider mechanisms. By phase shifting the two crank links, which are on a common crankshaft, the duty cycle of the valve is adjusted. The two spools split and re-co...

In this paper, a new multiobjective genetic algorithm is employed to support the design of a hydraulic actuation system. First, the proposed method is tested using benchmarks problems gathered from the literature. The method performs well and it is capable of identifying multiple Pareto frontiers in multimodal function spaces. Secondly, the method is applied to a mixed variable design problem w...

In this paper, the modeling and the control of a variable stiffness joint actuated by a couple of twisted string actuators in antagonistic configuration is reported. The twisted string actuation system is particularly suitable for very compact and light-weight robotic devices, like artificial hands and arms, and renders a very low apparent inertia at the load side, allowing the implementation o...

The effort–motion method, which describes the dynamics of openand closed-chain topologies of rigid bodies interconnected with revolute and prismatic pairs, is interpreted geometrically. Systems are identified for which the simultaneous control of forces and velocities is desirable, and a representative open-chain system is selected for use in the ensuing analysis. Gauge invariant transformation...

A passive biomimic PDMS valve applied in thermopneumatic micropump is firstly designed and realized. Unlike the conventional peristaltic pumping configuration, the micropump consists of two stacking layers of PDMS on a glass slide. This sandwich-type structure builds up two chambers. A thermopneumatic actuation chamber consists of a 57 ohm heater on the glass slide; the other fluid chamber is c...

This paper describes a microfluidic multi-injector (MMI) that can generate temporal and spatial concentration gradients of soluble molecules. Compared to conventional glass micropipette-based methods that generate a single gradient, the MMI exploits microfluidic integration and actuation of multiple pulsatile injectors to generate arbitrary overlapping gradients that have not previously been po...

This work evaluates proposed methods to correct engine power output as a function of atmospheric conditions. The analysis was made through experiments carried out in a vehicle on the road, under different temperature, pressure and air humidity conditions. The vehicle had a four-cylinder gasoline-fuelled engine, with multi-point fuel injection system, variable intake pipe length and variable int...