Lucas Industries Public Limited Company

Lucas Industries Limited

Trw Lucasvarity Electric Steering Limited

John M Ironside

Russell Wilson-Jones

Steven John Horton

Peter M Fox

Alistair M McQueen

David R Price

Michael Appleyard

Mark Anthony Wilkes

David G Williams

Anthony Walter Burton

Andrew James Stephen Williams

Andrew James Williams

Clive R Sainsbury

Russell Wilson Jones

Michael Holmes

Anthony C Wakeman

Duncan Barry Hodgson

Peter G Scotson

Brian Graham Nicholson

Paul Weston

David K Bryers

Russel Wilson-Jones

Christopher H Bramwell

Nigel A Deller

Simon C Barnard

David A Willcocks

A method of calculating the position of the rotor of a motor ( ) in for example an electrical power assisted steering assembly is disclosed. The method comprises the steps of measuring the output shaft ( ) (i.e. steering column) position, and scaling the measured value to produce an estimated motor rotor position value. This estimated value will be relative to an arbitrary datum point, and so the method further includes steps of adding an offset value derived from low resolution measurements of rotor position obtained using Hall effect sensors provided on the motor. Offsets for compensating for backlash and (in a second embodiment) compliance can also be included. Thus, the method allows high resolution information from an output shaft sensor (e.g. a torque sensor with a position dependent output) to be combined with the low resolution output from the Hall effect sensors to produce a high resolution rotor position signal. A correction is also made to allow for &ldquo;staleness&rdquo; in the Hall effect sensor output when calculating the offsets by monitoring rotor speed.

Position sensing in brushless motor systems

A motor control strategy for use in combination with an electric motor ( ) having a number of phase windings ( ) is disclosed, the motor ( ) being adapted to produce an output torque in response to current in the windings comprising the steps of during normal operation generating a motor torque demand signal indicative of the output torque required from the motor ( ), applying a first set of currents to the windings of the motor in response to the motor torque demand signal to produce a first output torque from the motor and during a test operation to enable diagnostics to be performed generating a motor current demand signal indicative of the total current required in the motor windings ( ) and adjusting the currents applied to one or more of the windings in response to both the torque demand signal and the motor current demand signal, whereby the adjusted currents produced in the windings are substantially equal to the total current demanded by the motor current demand signal regardless of the value of the motor torque demand signal and the motor ( ) produces a second output torque substantially equal to the first output torque produced during normal operation.

Method of controlling an electric motor having a number of phase windings

A circuit is provided for testing a drive stage of an actuator, such as a motor of an EPAS system. A power supply circuit comprises a contact for supplying normal drive stage current and a resistor for supplying reduced drive stage current before the normal current is supplied. A measuring circuit measures a drive stage electrical parameter such as supply voltage and a comparator compares this with an acceptable value. If the measured parameter corresponds to a current through the drive stage which is different from an expected value, a fault is signaled and the contact is prevented from closing.

Method of and circuit for testing an electrical actuator drive stage

An electrical power-assisted steering system is disclosed comprising a brushless electric motor (,) which has a plurality of phase windings connected at a start point and in which a switching means (,) such as a relay is provided in at least one phase of the motor, the switching means being movable between a closed position in which current is able to flow in the phase winding and an open position which prevents current flowing in the respective phase in the event of a fault. Also disclosed is a substantially rigid connector assembly (,) onto which is mounted the switching means (,), conductors (,) for connecting the motor phase windings and a motor position sensor (,) to an associated motor control means (,), the connector acting as a support for the motor stator, which simplifies the steps involved in assembly. In another aspect of the invention, the electrical power-assisted steering system includes a one-piece casing (,) which acts as a housing for the gearset, torque sensor, control means and at least part of the motor.

Electrical power-assisted steering systems

An electrical power-assisted steering system comprising a brushless electric motor which has a plurality of phase windings connected at a star point and in which a switching device such as a relay is provided in at least one phase of the motor, the switching device being movable between a closed position in which current is able to flow in the phase winding and an open position which prevents current flowing in the respective phase in the event of a fault.

A gearbox monitoring apparatus is disclosed for use in combination with a gearbox (,) which provides a connection between an input shaft (,) driven by a motor (,) and an output shaft (,), said gearbox monitoring apparatus comprising a first position sensing means (,) and a second position sensing means (,), said first and second position sensing means generating a respective first and second output signal, said first output signal being representative of the angular position of the input shaft and said second output signal being representative of the angular position of the output shaft, a torque signal generating means (,) which generates a third output signal representative of the torque carried by the gearbox (,), and signal processing means (,) adapted to receive said output signals and to process said output signals to produce one or more modified output signals representative of the wear in the gearbox.

Gearboxes

A control system comprises a controller for controlling an actuator, for instance of an electrically power assisted vehicle steering system. An unstable circuit, such as first and second cascade connected integrators has an input connected to the controller and an output connected to a detector, which signals an error when the output signal of the unstable circuit is outside an acceptable range. During normal operation, the controller supplies a signal to the unstable circuit such that its output signal remains within the acceptable range. The error signal may be used to disable the actuator, for instance so as to remove power assistance from steering system.

Control system

A torque sensor, or relative angular movement sensor, capable of measuring the angular displacement of a component in a power-assisted steering system, comprises an input member coupled to one end of a torsion bar, an output member coupled to another end of the torsion bar, LED light sources, a pair of photodetector units adapted to receive light from the LED light sources, and signal processing means adapted to receive output signals from the photodetector units, the output signals of the photodetector units being dependent upon the light signals which they receive, and wherein the signal processing means is adapted to produce a modified output signal which closely matches and is representative of the angular position of a chosen portion of the torsion bar. The signal processing comprises various stages in which the output signals from the photodetector units are processed to generate possible estimates of the instantaneous position of the chosen portion of the torsion bar and the best estimate is calculated and processed to provide a complete position estimate representing the angular position of the chosen portion relative to an arbitrarily chosen zero position.

Enhanced position signals in optical torque sensors

An engine control system generates a manifold pressure demand signal from an engine output demand signal provided by an accelerator pedal position transducer or a cruise control. The manifold pressure demand signal is compared with the actual inlet manifold pressure and the difference used to control an engine throttle and a turbocharger by means of a waste gate.

Turbocharged engine control system

An engine throttle control system comprises a control unit for controlling the position of a throttle by means of a motor in response to a position transducer actuated by an accelerator pedal. A detector detects when a signal produced by the control system is outside a range of acceptable values and, for instance, shuts down the engine. In one embodiment, the detector detects whether power supplied to the motor is less than a value expected on the basis of the position and speed of movement derived from the output of a throttle position sensor.

Engine throttle control system

An engine throttle control system comprises a control unit for controlling the position of a throttle by means of a motor in response to a position transducer actuated by an accelerator pedal. A detector detects when a signal produced by the control system is outside a range of acceptable values and, for instance, shuts down the engine. In one embodiment, the detector detects whether stress in an accelerator pedal return spring is less than a value expected.

An adaptive control system is provided for an internal combustion engine having at least two control inputs which affect an engine output. The system involves establishing a first base value for a first control input as a function of engine operating conditions and establishing a second base value for a second control input as a function of engine operating conditions. Corrections are applied in accordance with a predetermined control strategy to the first base value and the second base value to obtain a first corrected value for the first control input and a second corrected value for the second control input. A particular control input is periodically perturbed, and the engine output is monitored. The actual slope or differential of the engine output with respect to the particular control input is determined. The control strategy is predetermined to cause the actual slope to correspond to a desired value and to allow corrections to be applied to the first and second base values after corrections have become stabilized.

Adaptive control system for an engine

An engine throttle control system comprises a control unit for controlling the position of a throttle by means of a motor in response to a position transducer actuated by an accelerator pedal. A detector detects when a signal produced by the control system is outside a range of acceptable values and, for instance, shuts down the engine. In one embodiment, the detector detects whether power supplied to the motor is less then a value expected on the basis of the position and speed of movement derived from the output of a throttle position sensor.

An engine throttle control system actuates a throttle by means of a motor. In order to overcome static friction, a differentiator differentiates a throttle position demand signal and adds the differentiated signal to the demand signal. This composite signal is used by a control unit to drive the motor.

Growing community of inventors

Birmingham, United Kingdom

John M Ironside