Abstract: The invention relates to a cryogenic system for cooling a consumer having a time-variable heat load, such as a superconducting magnet, including: a cold box in thermal contact with the consumer, supplied with heat transfer gas compressed by a feed line, and connected to a delivery line for discharging said gas at a lower pressure; and an assembly for adjusting the pressures in the feed and delivery lines, comprising a plurality of controlled valves (CV1, CV2, CV3) and a controller (MC) for controlling the opening of said valves. The invention is characterized in that the controller is a multivariable controller for generating signals (SCs1, SCs2, SCs3) for controlling the opening of said valves according to measured values (PHP, PBP) and set values (P0HP, P0BP) for the pressures in the feed and delivery lines on the basis of a mathematical model of the system that factors in a coupling between the pressure values in the feed and delivery lines by means of the above-mentioned cold box.

Abstract: A process for estimating the speed of a vehicle or of an assemblage of vehicles, based on measuring the speeds of the mechanically independent wheels, while all the wheels are slipping with respect to the rolling surface, the process includes a step using mechanical and kinematic information characteristic of the vehicle or vehicles.

Abstract: In a process for controlling a rotating machine having n phases powered by a voltage inverter defining m.sup.n states of the stator phase voltage vector the electromagnetic torque .GAMMA. and the stator flux .vertline..phi..sub.s .vertline. of the machine are servocontrolled. A calculator calculates a succession of n states of the phase voltage vector to move the torque .GAMMA. and the flux .vertline..phi..sub.s .vertline. towards the set points .GAMMA..sub.ref, .vertline..phi..sub.s .vertline..sub.ref. On each sampling, the calculator calculates the remaining application time of the current state and the updated application times of the future states of the phase vector. Asynchronously with the sampling times and the calculation times, the calculator sends SPmLL switch control signals to switch from the current state to the next state.

Abstract: In a method of regulating a rotating machine with n phases fed with alternating current by a voltage inverter including n SPmLL defining m.sup.n states V.sub.i (i.epsilon.{1, . . , m.sup.n }) of the stator phase voltage vector V.sub.s, the machine having an electromagnetic torque T.sub.em and a stator flux .phi..sub.S slaved to a commanded electromagnetic torque T.sub.emref and stator flux .phi..sub.Sref, for transient conditions in which the electromagnetic torque T.sub.em and/or the stator flux .phi..sub.S are respectively far away from the commanded electromagnetic torque T.sub.emref and/or stator flux .phi..sub.Sref, from all possible states V.sub.i of the stator phase voltage vector V.sub.s, the one is chosen which is optimal for causing the torque T.sub.em and the stator flux .phi..sub.S to converge towards the commanded torque T.sub.emref and stator flux .phi..sub.Sref ; and switching of the SPmLL corresponding to the chosen state of the phase voltage vector V.sub.s is commanded.

Abstract: A system for the control of a paper machine headbox having sensors for the measurement of the parameters of the process and actuators of the members of the process, functionally connecting at least most of the sensors to an at least equal number of actuators via a multivariable centralized control member which makes it possible to control each actuator by the taking into account and processing of the measurement information of one or more sensors, and causing the measurement information to act on each of the sensors functionally connected to the actuators on one or more members to obtain a resultant action in which only the parameter measured by this sensor is influenced while the secondary repercussions on the outer parameters are eliminated. Another characteristic, the invention permits rapid intervention taking into account the information on the substance flow rate at the headbox, eliminating the usual disturbing influences due to the hydraulic values of the process.